Asbjørn Årøen

• Aae, Tommy Frøseth; Lian, Øystein Bjerkestrand; Årøen, Asbjørn; Engebretsen, Lars & Randsborg, Per-Henrik (2020). Compensation claims after knee cartilage surgery is rare. A registry-based study from Scandinavia from 2010 to 2015. BMC Musculoskeletal Disorders.  ISSN 1471-2474.  21 . doi: 10.1186/s12891-020-03311-4 Fulltekst i vitenarkiv. Vis sammendrag

  Background: Focal cartilage defects (FCDs) in the knee joint has a high prevalence. A broad range of treatment options exists for symptomatic patients. Knowledge of patient compensation claims following surgical treatment of FCDs is missing. The purpose of this study is to evaluate compensation claims filed to the Scandinavian registries for patient compensation following treatment of FCDs in the knee joint from 2010 to 2015 and identify possible areas of improvement. Methods: A cross-sectional study design was used to obtain all complaints following surgical treatment of FCDs from the Scandinavian registries from 2010 to 2015. Data such as age, gender, type of treatment, type of complaint, reason of verdict and amount of compensation were collected and systematically analyzed. Results: 103 patients filed a compensation claim. 43 had received debridement (41.7%), 54 microfracture (MF) (52.4%), 3 mosaicplasty (2.9%) and 3 autologous chondrocyte implantation (ACI) (2.9%). Of the 103 claims, 36 were granted (35%). 21 following debridement (58.3%), 13 after MF (36.1%), 1 following mosaicplasty (2.8%) and 1 after ACI (2.8%). The most common reason for complaint was infection (22.1%), of which 89% were granted. The average compensation was €24.457 (range €209 – €458.943). Conclusion: Compensation claims following surgical treatment of knee cartilage injuries in Scandinavia are rare. Establishing nationwide cartilage registries can add further knowledge on this troublesome disease.

• Kjennvold, Stian; Randsborg, Per-Henrik; Jakobsen, Rune Bruhn & Årøen, Asbjørn (2020). Fixation of acute chondral fractures in adolescent knees. Cartilage.  ISSN 1947-6035.  s 1- 9 . doi: 10.1177/1947603520941213
• Pollmann, Christian Thomas; Dahl, Fredrik Andreas; Røtterud, Jan H; Gjertsen, Jan Erik & Årøen, Asbjørn (2020). Surgical site infection after hip fracture – mortality and risk factors: an observational cohort study of 1,709 patients. Acta Orthopaedica.  ISSN 1745-3674.  91(3), s 347- 352 . doi: 10.1080/17453674.2020.1717841 Fulltekst i vitenarkiv. Vis sammendrag

  Background and purpose — Surgical site infection (SSI) is a devastating complication of hip fracture surgery. We studied the contribution of early deep SSI to mortality after hip fracture surgery and the risk factors for deep SSI with emphasis on the duration of surgery. Patients and methods — 1,709 patients (884 hemi­arthroplasties, 825 sliding hip screws), operated from 2012 to 2015 at a single center were included. Data were obtained from the Norwegian Hip Fracture Register, the electronic hospital records, the Norwegian Surveillance System for Antibiotic Use and Hospital-Acquired Infections, and the Central Population Register. Results — The rate of early (≤ 30 days) deep SSI was 2.2% (38/1,709). Additionally, for hemiarthroplasties 7 delayed (> 30 days, ≤ 1 year) deep SSIs were reported. In patients with early deep SSI 90-day mortality tripled (42% vs. 14%, p

• Wang, Katherine; Eftang, Cathrine N.; Jakobsen, Rune Bruhn & Årøen, Asbjørn (2020). Review of response rates over time in registry-based studies using patient-reported outcome measures. BMJ Open.  ISSN 2044-6055.  10 . doi: 10.1136/bmjopen-2019-030808 Vis sammendrag

  Objectives: Gain an overview of expected response rates (RRs) to patient-reported outcome measures (PROMs) in clinical quality registry-based studies and long-term cohorts in order to better evaluate the validity of registries and registry-based studies. Examine the trends of RRs over time and how they vary with study type, questionnaire format, and the use of reminders. Design: Literature review with systematic search. Data sources: PubMed, MEDLINE, EMBASE, kvalitetsregistre. no, kvalitetsregister. se and sundhed. dk. Eligibility criteria: Articles in all areas of medical research using registry-based data or cohort design with at least two follow-up time points collecting PROMs and reporting RRs. Annual reports of registries including PROMs that report RRs for at least two time points. Primary outcome measure: RRs to PROMs. Results: A total of 10 articles, 12 registry reports and 6 registry articles were included in the review. The overall RR at baseline was 75%±22.1 but decreased over time. Cohort studies had a markedly better RR (baseline 97%±4.7) compared with registry-based data at all time points (baseline 72%±21.8). For questionnaire formats, paper had the highest RR at 86%±19.4, a mix of electronic and paper had the second highest at 71%±15.1 and the electronic-only format had a substantially lower RR at 42%±8.7. Sending one reminder (82%±16.5) or more than one reminder (76%±20.9) to non-responders resulted in a higher RR than sending no reminders (39%±6.7). Conclusions: The large variation and downward trend of RRs to PROMs in cohort and registry-based studies are of concern and should be assessed and addressed when using registry data in both research and clinical practice.

• Pollmann, Christian Thomas; Røtterud, Jan H; Gjertsen, Jan-Erik; Dahl, Fredrik Andreas; Lenvik, Olav & Årøen, Asbjørn (2019). Fast track hip fracture care and mortality – an observational study of 2230 patients. BMC Musculoskeletal Disorders.  ISSN 1471-2474.  20 . doi: 10.1186/s12891-019-2637-6 Fulltekst i vitenarkiv. Vis sammendrag

  Background: Hip fracture patients are frail and have a high mortality. We investigated whether the introduction of fast track care reduced the 30-day mortality after hip fractures. Methods: Fast track hip fracture care was established at our institution in October 2013. Data from the Norwegian Hip Fracture Register and electronic hospital records were merged for 2230 hip fracture patients operated in our department from January 2012 through December 2015. 1090 of these patients were operated before (conventional treatment group) and 1140 patients were operated after the introduction of fast track care (fast track group). Data were analysed by univariate analysis and binary logistic regression. Results: Mortality did not differ significantly between the conventional treatment group and the fast track group at 30 days (7.9% vs. 6.5%), 90 days (13.5% vs. 12.5%) and one year (22.8% vs. 22.8%). Median admission time and time to surgery were significantly shorter in the fast track group than in the conventional treatment group (1.1 h vs. 3.9 h and 23.6 h vs. 25.7 h, both p < 0.0001). The 30-day reoperation rate was significantly lower in the fast track group compared to the conventional treatment group (odds ratio = 0.35 (95% CI: 0.15–0.84), p = 0.019). A composite 30- day outcome (reoperation, surgical site infection and/or death) was significantly less frequent in the fast track group (8.1%) than in the conventional treatment group (10.7%) in unadjusted analysis (p = 0.006), but not after adjusting for age, gender, cognitive impairment and ASA score (odds ratio = 0.85 (95% CI: 0.63–1.16), p = 0.31, 8.0% missing). Reoperations within 1 year, surgical site infections, 30-day readmissions and length of hospital stay did not differ significantly between the conventional treatment group and the fast track group. Conclusions: Fast track hip fracture care is safe. However, we observed no statistically significant change in 30-day, 90-day or 1-year mortality after the introduction of fast track hip fracture care

• Sailer, Monica Alessandra & Årøen, Asbjørn (2019). Bruk av lokal antibiotika ved rekonstruksjon av fremre korsbånd i Norge, I:  2019: Høstmøteboken - vitenskapelig program og abstrakter.  Norsk Ortopedisk Forening.  ISBN 978-82-994275-1-7.  Abstract.  s 86 - 86
• Straume-Næsheim, Truls Martin; Persson, Andreas & Årøen, Asbjørn (2019). Patellainstabilitetsregister - noe å bruke tid og ressurser på?, I:  2019: Høstmøteboken - vitenskapelig program og abstrakter.  Norsk Ortopedisk Forening.  ISBN 978-82-994275-1-7.  Abstract.  s 98 - 98
• Straume-Næsheim, Truls Martin; Randsborg, Per-Henrik; Mikaelsen, Jan Rune; Sivertsen, Einar; Devitt, Brian M.; Granan, Lars-Petter & Årøen, Asbjørn (2019). Recurrent lateral patella dislocation affects knee function as much as ACL deficiency – however patients wait five times longer for treatment. BMC Musculoskeletal Disorders.  ISSN 1471-2474.  20 . doi: 10.1186/s12891-019-2689-7 Fulltekst i vitenarkiv. Vis sammendrag

  Background: Surgical treatment of young patients with recurrent lateral patella dislocation (RLDP) is often recommended because of loss of knee function that compromises their level of activity or even their daily life functioning. This situation is comparable to young patients with an anterior cruciate ligament (ACL) rupture. The purpose of this study was therefore to explore the time from injury to surgery and the pre-operative symptoms and knee function of young RLPD patients scheduled for stabilizing surgery and compare this group to age and sex-matched ACL-deficient patients. Method: Forty-seven patients with unilateral RLPD listed for isolated medial patellofemoral ligament reconstruction were included in the study (RLPD-group). This group was compared to an age, sex and BMI matched ACL patient group obtained from the Norwegian knee ligament registry (ACL-group) for the following outcome measures: the knee injury and osteoarthritis outcome score (KOOS) assessed on the day of surgery and time from injury to surgery. Results: The RLPD-group scored significantly lower than the ACL-group for the three KOOS subscales “Pain” (73.6 vs. 79.8, p < 0.05), “Symptoms” (71.7 vs. 79.3, p < 0.05) and “ADL” (84.7 vs 89.5, p < 0.05). The lowest KOOS values were found for Sports/Recreation (53.5 vs. 51.3, p = 0.65) and Quality of life (37.6 vs. 36.7, p = 0.81). The average time from primary injury to surgery was 6 months for the ACL group and 31 months for the RLPD group. Conclusion: RLPD affected knee function as much as ACL deficiency, and was associated with more pain. Still the RLDP patients waited on average 5 times longer for surgery.

• Owesen, Christian; Røtterud, Jan H; Engebretsen, Lars & Årøen, Asbjørn (2018). Effect of Activity at Time of Injury and Concomitant Ligament Injuries on Patient- Reported Outcome After Posterior Cruciate Ligament Reconstruction. Orthopaedic Journal of Sports Medicine (OJSM).  ISSN 2325-9671.  6(12) . doi: 10.1177/2325967118817297 Fulltekst i vitenarkiv.
• Ulstein, Svend; Årøen, Asbjørn; Engebretsen, Lars; Forssblad, Magnus; Lygre, Stein Håkon Låstad & Røtterud, Jan H (2018). A Controlled Comparison of Microfracture, Debridement, and No Treatment of Concomitant Full-Thickness Cartilage Lesions in Anterior Cruciate Ligament-Reconstructed Knees: A Nationwide Prospective Cohort Study From Norway and Sweden of 368 Patients With 5-Year Follow-up. Orthopaedic Journal of Sports Medicine (OJSM).  ISSN 2325-9671.  6(8) . doi: 10.1177/2325967118787767 Fulltekst i vitenarkiv. Vis sammendrag

  Background: The effect of microfracture (MF) or surgical debridement of concomitant full-thickness cartilage lesions in anterior cruciate ligament–reconstructed knees on patient-reported outcomes remains to be determined. Purpose: To evaluate the effect of debridement or MF compared with no surgical treatment of concomitant full-thickness cartilage lesions on patient-reported outcomes 5 years after anterior cruciate ligament reconstruction (ACLR). Study Design: Cohort study; Level of evidence, 2. Methods: Included in this study were 644 patients who were registered in the Norwegian and the Swedish National Knee Ligament Registries from 2005 to 2008 as having undergone unilateral primary ACLR and having a concomitant full-thickness cartilage lesion (International Cartilage Repair Society [ICRS] grades 3-4). Of these patients, 129 were treated with debridement, 164 were treated with MF, and 351 received no surgical treatment simultaneously with ACLR. At 5-year follow-up, 368 (57%) patients completed results on the Knee injury and Osteoarthritis Outcome Score (KOOS).Multivariable linear regression was used to estimate the effect of surgical debridement or MF of concomitant full-thickness cartilage lesions on patient-reported outcomes 5 years after ACLR. Results: Compared with no surgical treatment, there were no unadjusted or adjusted effects of debridement or MF of concomitant full-thickness cartilage lesions on KOOS scores at 5-year follow-up. Conclusion: Compared with leaving concomitant full-thickness cartilage lesions untreated at the time of ACLR, debridement and MF showed no effect on patient-reported outcomes 5 years after surgery.

• Ulstein, Svend; Årøen, Asbjørn; Engebretsen, Lars; Forssblad, Magnus; Lygre, Stein Håkon Låstad & Røtterud, Jan H (2018). Effect of concomitant cartilage lesions on patient-reported outcomes after anterior cruciate ligament reconstruction. A Nationwide chohort study from Norway and Sweden of 8470 patients With 5 year follow-up. Orthopaedic Journal of Sports Medicine (OJSM).  ISSN 2325-9671.  6:2325967118786219(7), s 1- 7 . doi: 10.1177/2325967118786219 Fulltekst i vitenarkiv.
• Aae, Tommy Frøseth; Randsborg, Per-Henrik; Lurås, Hilde; Årøen, Asbjørn & Lian, Øystein Bjerkestrand (2017). Microfracture is more cost-effective than autologous chondrocyte implantation: a review of level 1 and level 2 studies with 5 year follow-up. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  26(4), s 1044- 1052 . doi: 10.1007/s00167-017-4802-5 Fulltekst i vitenarkiv.
• Engen, Cathrine Nørstad; Løken, Sverre Bertrand; Årøen, Asbjørn; Ho, Charles & Engebretsen, Lars (2017). No degeneration found in focal cartilage defects evaluated with dGEMRIC at 12-year follow-up. Acta Orthopaedica.  ISSN 1745-3674.  88(1), s 82- 89 . doi: 10.1080/17453674.2016.1255484 Vis sammendrag

  Background and purpose: The natural history of focal cartilage defects (FCDs) is still unresolved, as is the long-term cartilage quality after cartilage surgery. It has been suggested that delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a biomarker of early OA. We aimed to quantitatively evaluate the articular cartilage in knees with FCDs, 12 years after arthroscopic diagnosis. Patients and methods: We included 21 patients from a cohort of patients with knee pain who underwent arthroscopy in 1999. Patients with a full-thickness cartilage defect, stable knees, and at least 50% of both their menisci intact at baseline were eligible. 10 patients had cartilage repair performed at baseline (microfracture or autologous chondrocyte implantation), whereas 11 patients had either no additional surgery or simple debridement performed. Mean follow-up time was 12 (10–13) years. The morphology and biochemical features were evaluated with dGEMRIC and T2 mapping. Standing radiographs for Kellgren and Lawrence (K&L) classification of osteoarthritis (OA) were obtained. Knee function was assessed with VAS, Tegner, Lysholm, and KOOS. Results: The dGEMRIC showed varying results but, overall, no increased degeneration of the injured knees. Degenerative changes (K&L above 0) were, however, evident in 13 of the 21 knees. Interpretation: The natural history of untreated FCDs shows large dGEMRIC variations, as does the knee articular cartilage of surgically treated patients. In this study, radiographic OA changes did not correlate with cartilage quality, as assessed with dGEMRIC.

• Engen, Cathrine Nørstad; Årøen, Asbjørn & Engebretsen, Lars (2017). Development of a pilot cartilage surgery register. BMC Musculoskeletal Disorders.  ISSN 1471-2474.  18(282), s 1- 8 . doi: 10.1186/s12891-017-1638-6 Fulltekst i vitenarkiv. Vis sammendrag

  Background: Norway has no prospective surveillance system to monitor the outcome of knee cartilage surgery. In 2004 the Norwegian Registry of Knee Ligament (NKLR) was successfully established, and has yielded useful information on the treatment of patients with both knee ligament and combined knee injuries. Patients with focal cartilage defects (FCDs) in their knees have reduced function and the treatment is difficult. There are geographical variations in treatment, and the generalizability from randomized controlled studies is low. These patients would benefit from a standardized long-time follow-up through a cartilage surgery register. The aim of the present study was to describe the development and report baseline challenges during the setting up of a pilot of a knee cartilage surgery register. Methods: The study was designed as a prospective cohort study in the form of a register. Patients with full-thickness FCDs in the knee with International Cartilage Repair Society (ICRS) grade 3–4 on arthroscopy were included. The pilot included two hospitals; Oslo University Hospital (OUS), Ullevål and Akershus University Hospital (Ahus). Results: We registered 58 patients with isolated FCDs, whereas 16 additional patients with full-thickness FCDs were registered through the NKLR. The patient cohort of patients with isolated FCDs consisted of 65% men and had a mean age of 29.8 years. The data are incomplete and the compliance varies from 18 to 73%. The distribution of mean KOOS scores were similar to previous patient cohorts with FCDs, with low scores for the KOOS Sport/Recreation and Quality of Life subscales. Conclusion: The level of compliance demonstrated a large difference between the two participating hospitals. The compliance for the isolated FCDs were low in both locations, although it reached an acceptable level in one hospital when patients with combined injuries from the NKLR were included. The forms were incompletely filled out by the surgeons postoperatively and need to be revised prior the establishment of a nation-wide register.

• Owesen, Christian; Aas, Eline & Årøen, Asbjørn (2017). Surgical reconstruction is a cost-efficient treatment option for isolated PCL injuries. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  s 1- 6 . doi: 10.1007/s00167-017-4632-5
• Owesen, Christian; Sandven-Thrane, Stine; Lind, Martin; Forssblad, Magnus; Granan, Lars-Petter & Årøen, Asbjørn (2017). Epidemiology of surgically treated posterior cruciate ligament injuries in Scandinavia. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  25(8), s 2384- 2391 . doi: 10.1007/s00167-015-3786-2
• Aae, Tommy Frøseth; Randsborg, Per-Henrik; Breen, Anne Berg; Visnes, Håvard; Vindfeld, Søren; Sivertsen, Einar; Løken, Sverre Bertrand; Brinchmann, Jan E.; Hanvold, Heidi Andreassen & Årøen, Asbjørn (2016). Norwegian Cartilage Project - a study protocol for a double-blinded randomized controlled trail comparing arthroscopic microfracture with debridement in focal cartilage defects in the knee. BMC Musculoskeletal Disorders.  ISSN 1471-2474.  17:292 . doi: 10.1186/s12891-016-1156-y
• Randsborg, Per-Henrik; Brinchmann, Jan E.; Løken, Sverre Bertrand; Hanvold, Heidi Andreassen; Aae, Tommy Frøseth & Årøen, Asbjørn (2016). Focal cartilage defects in the knee -a randomized controlled trial comparing autologous chondrocyte implantation with arthroscopic debridement. BMC Musculoskeletal Disorders.  ISSN 1471-2474.  17(1) . doi: 10.1186/s12891-016-0969-z Vis sammendrag

  Background: Focal cartilage injuries in the knee might have devastating effect due to the predisposition of early onset osteoarthritis. Various surgical treatment options are available, however no statistically significant differences have been found between the different surgical treatments. This supports the suggestion that the improvement might be a result of the post-operative rehabilitation rather than the surgery itself. Autologous chondrocyte implantation (ACI) has become a recognized treatment option for larger cartilage lesions in the knee. Although ACI has been compared to other surgical treatment such as microfracture and mosaicplasty, it has never been directly compared to simple arthroscopic debridement and rehabilitation alone. In this study we want to increase clinical and economic knowledge about autologous chondrocyte implantation compared to arthroscopic debridement and physical rehabilitation in the short and long run. Methods/Design: We will conduct a randomized controlled trial to compare ACI with simple arthroscopic debridement (AD) and physiotherapy for the treatment of cartilage lesions in the knee. The study will include a total of 82 patients, both men and non-pregnant women, with a full thickness cartilage defect in the weight bearing area of the femoral condyles or trochlea larger than 2 cm2. The lesion must be symptomatic, with a Lysholm score less than 75. The two treatment groups will receive identical rehabilitation protocol according to a modification of Wondrasch et al., which is an active rehabilitation and education program divided into 3 phases: accommodation, rehabilitation and return to activity. The patients will be followed for 24 months, with additional late follow-ups at 5 and 10 years to monitor the potential onset of osteoarthtitis. The primary outcome measure will be the difference in the KOOS knee-related quality of life (QoL) subscore in the ACI group compared to the AD group at 2 years. A combination of self-explanatory questionnaires, clinical parameters, clinical hop tests and radiographs and Magnetic Resonance Imaging (MRI) will be used as secondary endpoints. Discussion: This is the first study with a high level of evidence to compare ACI with simple debridement and physiotherapy for the treatment of isolated symptomatic full thickness lesions of the knee.

• Røtterud, Jan H; Sivertsen, Einar; Forssblad, Magnus; Engebretsen, Lars & Årøen, Asbjørn (2016). Effect on Patient-Reported Outcomes of Debridement or Microfracture of Concomitant Full-Thickness Cartilage Lesions in Anterior Cruciate Ligament-Reconstructed Knees: A Nationwide Cohort Study from Norway and Sweden of 357 Patients with 2-Year Follow-up. American Journal of Sports Medicine.  ISSN 0363-5465.  44(2), s 337- 344 . doi: 10.1177/0363546515617468 Vis sammendrag

  Background: The treatment of concomitant cartilage lesions in anterior cruciate ligament (ACL)–injured knees is debatable. Purpose: To evaluate the effect of debridement or microfracture (MF) compared with no treatment of concomitant full-thickness (International Cartilage Repair Society [ICRS] grades 3-4) cartilage lesions on patient-reported outcomes after ACL reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: Six hundred forty-four patients who underwent primary unilateral ACL reconstruction and had a concomitant fullthickness cartilage lesion treated simultaneously by debridement (n = 129) or MF (n = 164), or underwent no treatment (n = 351) of the cartilage lesion, registered in the Norwegian and Swedish National Knee Ligament Registries from 2005 to 2008 were included. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was used to measure patient-reported outcomes. At a mean follow-up of 2.1 6 0.2 years after surgery, 357 (55%) patients completed the KOOS. Linear regression analyses were used to evaluate the effect of debridement or MF on the KOOS. Results: No significant effects of debridement were detected in the unadjusted or adjusted regression analyses on any of the KOOS subscales at 2-year follow-up. The MF treatment of the cartilage lesions had significant negative effects at 2-year follow-up on the KOOS Sport and Recreation (Sport/Rec) (regression coefficient [b] = –8.9; 95% confidence interval [CI], –15.1 to –1.5) and Knee-Related Quality of Life (QoL) (b = –8.1; 95% CI, –14.1 to –2.1) subscales in the unadjusted analyses. When adjusting for confounders, MF had significant negative effects on the same KOOS subscales of Sport/Rec (b = –8.6; 95% CI, –16.4 to –0.7) and QoL (b = –7.2; 95% CI, –13.6 to –0.8). For the remaining KOOS subscales of Pain, Symptoms, and Activities of Daily Living, there were no significant unadjusted or adjusted effects of MF. Conclusion: MF of concomitant full-thickness cartilage lesions showed adverse effects on patient-reported outcomes at 2-year follow-up after ACL reconstruction. Debridement of concomitant full-thickness cartilage lesions showed neither positive nor negative effects on patient-reported outcomes at 2-year follow-up after ACL reconstruction.

• Ulstein, Svend; Bredland, Karin; Årøen, Asbjørn; Engebretsen, Lars & Røtterud, Jan H (2016). No negative effect on patient-reported outcome of concomitant cartilage lesions 5–9 years after ACL reconstruction. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  24, s 340- 341 . doi: 10.1007/s00167-016-4163-5 Vis sammendrag

  Purpose: To compare patient-reported outcome 5–9 years after anterior cruciate ligament (ACL) reconstruction in patients with and without a concomitant full-thickness [International Cartilage Repair Society (ICRS) grade 3–4] cartilage lesion. Methods: This is a prospective follow-up of a cohort of 89 patients that were identified in the Norwegian National Knee Ligament Registry and included in the current study in 2007, consisting of 30 primary ACL-reconstructed patients with a concomitant, isolated full-thickness cartilage lesion (ICRS grade 3 and 4) and 59 matched controls without cartilage lesions (ICRS grade 1–4). At a median follow-up of 6.3 years (range 4.9–9.1) after ACL reconstruction, 74 (84 %) patients completed the Knee Injury and Osteoarthritis Outcome Score (KOOS), which was used as the main outcome measure. Secondary outcomes included radiographic evaluation according to the Kellgren– Lawrence criteria of knee osteoarthritis (OA). Results At follow-up, 5–9 years after ACL reconstruction, no statistically significant differences in KOOS were detected between patients with a concomitant full-thickness cartilage lesion and patients without concomitant cartilage lesions. Radiographic knee OA of the affected knee,defined as Kellgren and Lawrence ≥2, was significantly more frequent in subjects without a concomitant cartilage lesion (p = 0.016). Conclusion: ACL reconstruction performed in patients with an isolated concomitant full-thickness cartilage lesion restored patient-reported knee function to the same level as ACL reconstruction performed in patients without concomitant cartilage lesions, 5–9 years after surgery. This should be considered in the preoperative information given to patients with such combined injuries, in terms of the expected outcome after ACL reconstruction and in the counselling and decision-making on the subject of surgical treatment of the concomitant cartilage lesion. Level of evidence: Prognostic; prospective cohort study, Level I.

• Årøen, Asbjørn; Brøgger, Helga Marie; Røtterud, Jan H; Sivertsen, Einar Andreas; Engebretsen, Lars & Risberg, May Arna (2016). Evaluation of focal cartilage lesions of the knee using MRI T2 mapping and delayed Gadolinium Enhanced MRI of Cartilage (dGEMRIC). BMC Musculoskeletal Disorders.  ISSN 1471-2474.  17(1) . doi: 10.1186/s12891-016-0941-y
• Engen, Cathrine Nørstad; Løken, Sverre Bertrand; Årøen, Asbjørn & Engebretsen, Lars (2015). Elleve år gamle fokale bruskskader i knær, bedømt med dgermic, I: Terje Vagstad (red.),  Høstmøteboken - Vitenskapelig program og abstrakter 2015.  Norsk Ortopedisk Forening.  Høstmøteboken - vitenskapelig program og abstrakter 2015.  s 195
• Engen, Cathrine Nørstad; Årøen, Asbjørn & Engebretsen, Lars (2015). Incidence of knee cartilage surgery in Norway, 2008-2011. BMJ Open.  ISSN 2044-6055.  5(11) . doi: 10.1136/bmjopen-2015-008423 Fulltekst i vitenarkiv. Vis sammendrag

  Objective: A systematic and long-term data collection on the treatment of focal cartilage defects (FCDs) of the knee is needed. This can be achieved through the foundation of a National Knee Cartilage Defect Registry. The aim of this study was to establish the nationwide burden of knee cartilage surgery, defined as knee surgery in patients with an FCD. We also aimed to identify any geographical differences in incidence rates, patient demographics or trends within this type of surgery. Setting: A population-based study with retrospective identification of patients undergoing knee cartilage surgery in Norway through a mandatory public health database from 2008 to 2011. Participants: We identified all patients undergoing cartilage surgery, or other knee surgery in patients with an FCD. All eligible surgeries were assessed for inclusion on the basis of certain types of ICD-10 and NOMESKO Classification of Surgical Procedures codes. Primary and secondary outcome measures: The variables were diagnostic and surgical codes, geographic location of the performing hospital, age and sex of the patients. Yearly incidence and incidence rates were calculated. Age-adjusted incidences for risk ratios and ORs between geographical areas were also calculated. Results: A total of 10 830 cases of knee cartilage surgery were identified, with slight but significant decreases from 2008 to 2011 (p<0.0003). The national incidence rate was 56/100 000 inhabitants and varied between regions, counties and hospitals. More than 50% of the procedures were palliative and nearly 400 yearly procedures were reparative or restorative. Conclusions: Knee cartilage surgery is common in Norway, counting 2500 annual cases with an ageadjusted incidence rate of 68.8/100 000 inhabitants. There are significant geographical variations in incidence and trends of surgery and in trends between public and private hospitals. We suggest that a national surveillance system would be beneficial for the future evaluation of the treatment of these patients.

• Owesen, Christian; Sandven-Thrane, Stine; Lind, M; Granan, Lars-Petter & Årøen, Asbjørn (2015). Epidemiology of surgically treated posterior cruciate ligament injuries in scandinavia, In Terje Vagstad (ed.),  Høstmøteboken - Vitenskapelig program og abstrakter 2015.  Norsk Ortopedisk Forening.  Høstmøteboken - vitenskapelig program og abstrakter 2015.  s 204
• Owesen, Christian; Sivertsen, Einar Andreas; Engebretsen, Lars; Granan, Lars-Petter & Årøen, Asbjørn (2015). Patients With Isolated PCL Injuries Improve From Surgery as Much as Patients With ACL Injuries After 2 Years. Orthopaedic Journal of Sports Medicine (OJSM).  ISSN 2325-9671.  3(8) . doi: 10.1177/2325967115599539 Vis sammendrag

  Background: Reports on outcome after posterior cruciate ligament (PCL) reconstruction often contain both isolated PCL and combined knee ligament injuries. This makes it difficult to conclude on the outcome after reconstruction of isolated PCL injuries. Purpose: To investigate the outcome after PCL reconstruction in patients with an isolated PCL injury and to compare this with the outcome of patients treated with reconstruction after isolated anterior cruciate ligament (ACL) injuries. Study Design: Cohort study; Level of evidence, 3. Methods: Seventy-one patients with an isolated PCL injury that was reconstructed surgically and who had registered in the Norwegian Knee Ligament Registry between 2004 and 2010 were included in this study. Patients with isolated ACL reconstructions (n ¼ 9661) who had registered in the same period were included for comparison. Knee Injury and Osteoarthritis Outcome Score (KOOS) was used as the patient-reported outcome measure. Preoperative and 2-year postoperative KOOS scores were compared. Changes in KOOS score reported by the PCL patients were compared with changes reported by the ACL patients. Results: At the 2-year postoperative follow-up of the PCL-reconstructed patients, the patient-reported outcome was improved, measured by KOOS as follows: pain, 15.1 (95% CI, 8.5-21.8; P < .001); symptoms, 0.9 (95% CI, –6.6 to 8.3; P ¼ .82); activities of daily living, 13.2 (95% CI, 6.6-13.9; P < .001); sports, 20.7 (95% CI, 11.8-29.4; P < .001); and quality of life, 26.6 (95% CI, 18.9-34.2; P < .001). According to the KOOS, the incremental improvements were similar for PCL and ACL patients. Time from injury to surgery was longer for the PCL patients compared with ACL patients (median, 21.5 vs 8.0 months; P < .001). Conclusion: Patients undergoing PCL reconstruction can expect the same improvements in KOOS score as patients undergoing ACL reconstruction. However, PCL patients start out with an inferior score on average and consequently end up at a lower score compared with ACL patients for all KOOS subscales.

• Straume-Næsheim, Truls Martin; Mikaelsen, JR; Sivertsen, EA; Devitt, Brian M.; Brand, J; Granan, Lars-Petter & Årøen, Asbjørn (2015). Symptomer og funksjon hos pasienter med residiverende patellaluksasjon sammenlignet med pasienter med fremre korsbåndsskade., I: Terje Vagstad (red.),  Høstmøteboken - Vitenskapelig program og abstrakter 2015.  Norsk Ortopedisk Forening.  Høstmøteboken - vitenskapelig program og abstrakter 2015.  s 197
• Røtterud, Jan H; Reinholt, Finn P.; Beckstrøm, Karen Johanne; Risberg, May Arna & Årøen, Asbjørn (2014). Relationship between CTX-II and patient characteristics, patient-reported outcome, muscle strength, and rehabilitation in patients with a focal cartilage lesion of the knee: A prospective exploratory cohort study of 48 patients. BMC Musculoskeletal Disorders.  ISSN 1471-2474.  15(1) . doi: 10.1186/1471-2474-15-99 Vis sammendrag

  Background: C-telopeptide fragments of type II collagen (CTX-II) are created during articular cartilage breakdown and CTX-II is considered useful as a biomarker of osteoarthritis. The primary objective of the present study was to explore the relationship between urinary CTX-II concentration and patient characteristics, patient-reported outcome, muscle strength, and rehabilitation in patients with isolated focal knee cartilage lesions. Furthermore, the secondary objective was to examine differences in urinary CTX-II concentration between patients with focal cartilage lesions and healthy controls. Methods: 48 patients (mean age 33.4 years, standard deviation 9.0) with a focal full-thickness (International Cartilage Repair Society grade 3 or 4) cartilage lesion on the medial or lateral femoral condyle were included. After baseline assessments, the patients completed a 3-month rehabilitation program and 44 patients attended the 3 month follow-up. Baseline and follow-up assessments consisted of urinary CTX-II, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and isokinetic quadriceps and hamstring muscle strength measurements. CTX-II was also analysed in urine samples from 6 healthy individuals, serving as normal controls. Correlations were classified as very weak (correlation coefficient [r] < 0.20), weak (r = 0.20 – 0.39), moderate (r = 0.40 – 0.59), strong (r = 0.60 – 0.79), and very strong (r > 0.80). Results: Except for age and quadriceps strength, no significant correlations were found between CTX-II concentrations and baseline characteristics, KOOS, or muscle strength. Except for age, all correlations were considered as weak or very weak. The patients with a focal cartilage lesion had significantly higher mean CTX-II concentration than the healthy control individuals both at baseline (p = 0.001) and at follow-up (p = 0.001). The mean CTX-II concentration tended to decrease during rehabilitation, but the reduction was not significant (p = 0.076). Conclusions: The current exploratory study demonstrated that patients with a focal cartilage lesion of the knee had higher concentrations of urinary CTX-II than healthy individuals. In addition, CTX-II concentration tended to decrease during rehabilitation.

• Sivertsen, Einar; Wagner, LR; Lind, M; Granan, Lars-Petter; Skråmm, Inge & Årøen, Asbjørn (2014). Infeksjon etter ACL rekonstruksjon. Data fra de norske og danske korsbåndregistrene, I: Jon Olav Drogset (red.),  Høstmøteboken : vitenskapelig program og abstrakter 2014.  Norsk ortopedisk forening.  abstract.  s 2012
• Skråmm, Inge; Moen, Aina Elisabeth Fossum; Årøen, Asbjørn & Bukholm, Geir (2014). Surgical Site Infections in Orthopaedic Surgery Demonstrate Clones Similar to Those in Orthopaedic Staphylococcus aureus Nasal Carriers. Journal of Bone and Joint Surgery. American volume.  ISSN 0021-9355.  96, s 882- 888 . doi: 10.2106/JBJS.M.00919
• Smith, Sean D; LaPrade, Robert F.; Jansson, Kyle S; Årøen, Asbjørn & Wijdicks, Coen A. (2014). Functional bracing of ACL injuries: current state and futuer directions. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  22(5), s 1131- 1141 . doi: 10.1007/s00167-013-2514-z
• Ulstein, Svend; Bredland, K; Årøen, Asbjørn; Engebretsen, Lars & Røtterud, Jan H (2014). Ingen negativ effekt av fulltykkelse bruskskade hos fremre korsbånd rekonstruerte pasienter ved 5-9 års oppfølging, I: Jon Olav Drogset (red.),  Høstmøteboken : vitenskapelig program og abstrakter 2014.  Norsk ortopedisk forening.  abstract.  s 213
• Ulstein, Svend; Årøen, Asbjørn; Røtterud, Jan H; Løken, Sverre Bertrand; Engebretsen, Lars & Heir, Stig (2014). Microfracture technique versus osteochondral autologous transplantation mosaicplasty in patients with articular chondral lesions of the knee: a prospective randomized trial with long-term follow-up. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  22(6), s 1207- 1215 . doi: 10.1007/s00167-014-2843-6 Vis sammendrag

  Purpose: To compare long-term functional and radiological outcome following microfracture technique (MF) versus osteochondral autologous transplantation (OAT) mosaicplasty for treating focal chondral lesions of the knee. Methods: Twenty-five patients (mean age 32.3 years, SD 7.7) with a full-thickness (International Cartilage Repair Society grade 3 or 4) chondral lesion of the articulating surface of the femur were randomized to either MF (n = 11) or OAT mosaicplasty (n = 14). At a median follow-up of 9.8 years (range 4.9–11.4), the patients were evaluated using Lysholm score (n = 25), Knee Injury and Osteoarthritis Outcome Score (KOOS, n = 25), isokinetic quadriceps measurement and hamstring strength measurement (n = 22) and standing radiographs (n = 23). Results: There were no significant differences in Lysholm score, KOOS, isokinetic muscle strength or radiographic osteoarthritis between MF-treated patients and OAT mosaicplasty-treated patients at follow-up. Mean Lysholm score at follow-up was 69.7 [95 % confidence interval (CI), 55.1–84.4] for the MF group and 62.6 (95 % CI, 52.6–72.6) for the OAT mosaicplasty group. Conclusion: At long-term follow-up, there were no significant differences between patients treated with MF and patients treated with OAT mosaicplasty in patient-reported outcomes, muscle strength or radiological outcome. Level of evidence: Therapeutic study, Level II.

• Kennedy, Nicholas I.; Wijdicks, Coen A.; Goldsmith, Mary T; Michalski, Max P.; Devitt, Brian M.; Årøen, Asbjørn; Engebretsen, Lars & LaPrade, Robert F. (2013). Kinematic Analysis of the Posterior Cruciate Ligament, Part 1 : The Individual and Collective Function of the Anterolateral and Posteromedial Bundles. American Journal of Sports Medicine.  ISSN 0363-5465.  41(12), s 2828- 2838 . doi: 10.1177/0363546513504287
• Randsborg, Per-Henrik; Gulbrandsen, Pål; Sivertsen, Einar; Hammer, Ola-Lars; Fuglesang, Hendrik Frølich; Årøen, Asbjørn & Saltyte Benth, Jurate (2013). Fractures in children: epidemiology and activity-specific fracture rates. Journal of Bone and Joint Surgery. American volume.  ISSN 0021-9355.  95(3) . doi: 10.2106/JBJS.L.00369
• Røtterud, Jan H; Sivertsen, Einar; Forssblad, Magnus; Engebretsen, Lars & Årøen, Asbjørn (2013). Effect of Meniscal and Focal Cartilage Lesions on Patient-Reported Outcome After Anterior Cruciate Ligament Reconstruction : A Nationwide Cohort Study From Norway and Sweden of 8476 Patients With 2-Year Follow-up. American Journal of Sports Medicine.  ISSN 0363-5465.  41(3), s 535- 543 . doi: 10.1177/0363546512473571 Vis sammendrag

  Background: The effect of concomitant intra-articular injury on patient-reported outcome after anterior cruciate ligament (ACL) reconstruction is debated. Purpose: To evaluate the effect of meniscal and articular cartilage lesions on patient-reported outcome 2 years after ACL reconstruction. Study Design: Cohort study (prognosis); Level of evidence, 2. Methods: The study included all patients with primary, unilateral ACL reconstruction registered in the Norwegian and the Swedish National Knee Ligament Registry from 2005 through 2008 who had completed the Knee Injury and Osteoarthritis Outcome Score (KOOS) Knee-Related Quality of Life subscale at a 2-year follow-up (mean 6 SD, 2.1 6 0.2 years) after surgery (n = 8476). Multiple linear regression analyses were used to evaluate the associations between each KOOS subscale (Pain, Other Symptoms, Activities of Daily Living, Sport and Recreation Function, Knee-Related Quality of Life) as the measure for patient-reported outcome and meniscal and cartilage lesions. Results: A total of 3674 (43%) patients had meniscal lesion(s), 1671 (20%) had partial-thickness (International Cartilage Repair Society [ICRS] grades 1-2) cartilage lesion(s), and 551 (7%) had full-thickness (ICRS grades 3-4) cartilage lesion(s). Multiple linear regression analyses detected no significant associations between meniscal lesions or partial-thickness cartilage lesions and the scores in any of the KOOS subscales at the 2-year follow-up. Full-thickness cartilage lesions were significantly associated with decreased scores in all of the KOOS subscales. Conclusion: Patients with concomitant full-thickness cartilage lesions reported worse outcome in all of the KOOS subscales compared with patients without cartilage lesions 2 years after ACL reconstruction. Meniscal lesions and partial-thickness cartilage lesions did not impair patient-reported outcome 2 years after ACL reconstruction.

• Wijdicks, Coen A.; Kennedy, Nicholas I.; Goldsmith, Mary T; Devitt, Brian M.; Michalski, Max P.; Årøen, Asbjørn; Engebretsen, Lars & LaPrade, Robert F. (2013). Kinematic Analysis of the Posterior Cruciate Ligament, Part 2 : A Comparison of Anatomic Single- Versus Double-Bundle Reconstruction. American Journal of Sports Medicine.  ISSN 0363-5465.  41(12), s 2839- 2848 . doi: 10.1177/0363546513504384
• Wondrasch, Barbara; Årøen, Asbjørn; Røtterud, Jan H; Høysveen, Turid; Bølstad, Kristin & Risberg, May Arna (2013). The Feasibility of a 3-Month Active Rehabilitation Program for Patients With Knee Full-Thickness Articular Cartilage Lesions: The Oslo Cartilage Active Rehabilitation and Education Study. Journal of Orthopaedic and Sports Physical Therapy.  ISSN 0190-6011.  43(5), s 310- 324 . doi: 10.2519/jospt.2013.4354 Vis sammendrag

  Study Design: Case series. Objectives: To evaluate the feasibility of an active rehabilitation program for patients with knee full-thickness articular cartilage lesions. Background: No studies have yet evaluated the effect of active rehabilitation in patients with knee full-thickness articular cartilage lesions or compared the effects of active rehabilitation to those of surgical interventions. As an initial step, the feasibility of such a program needs to be described. Methods: Forty-eight patients with a knee full-thickness articular cartilage lesion and a Lysholm score below 75 participated in a 3-month active rehabilitation program consisting of cardiovascular training, knee and hip progressive resistance training, and neuromuscular training. Feasibility was determined by monitoring adherence to the program, clinical changes in knee function, load progression, and adverse events. Patients were tested before and after completing the rehabilitation program by using patient-reported outcomes (Knee injury and Osteoarthritis Outcome Score, International Knee Documentation Committee Subjective Knee Evaluation Form 2000) and isokinetic muscle strength and hop tests. To monitor adherence, load progression, and adverse events, patients responded to an online survey and kept training diaries. Results: The average adherence rate to the rehabilitation program was 83%. Four patients (9%) showed adverse events, as they could not perform the exercises due to pain and effusion. Significant and clinically meaningful improvement was found, based on changes on the International Knee Documentation Committee Subjective Knee Evaluation Form 2000, the Knee injury and Osteoarthritis Outcome Score quality of life subscale, isokinetic muscle strength, and hop performance (P<.05), with small to large effect sizes (standardized response mean, 0.3–1.22). Conclusion: The combination of a high adherence rate, clinically meaningful changes, and positive load progression and the occurrence of only a few adverse events support the potential usefulness of this program for patients with knee full-thickness cartilage lesions. This study was registered with the public trial registry Clinical Trials.gov (NCT00885729).

• Årøen, Asbjørn; Røtterud, Jan H & Sivertsen, Einar (2013). Agreement in Arthroscopic and Arthrotomy Assessment of Full-Thickness Articular Cartilage Lesions of the Knee in a Clinical Setting in 33 Consecutive Patients. Cartilage.  ISSN 1947-6035. . doi: 10.1177/1947603513483546 Vis sammendrag

  Objective: To evaluate the accuracy of arthroscopic measurement of full-thickness (International Cartilage Repair Society grades 3-4) cartilage lesions of the knee. Design: In 33 consecutive arthroscopically evaluated cartilage lesion knees the lesion size was routinely estimated. At the final treatment, a knee arthrotomy was performed, and the lesion was reestimated. The 2 estimates were then compared by paired t test and the area estimated by knee arthrotomy was used as the gold standard. Results: The mean area of the cartilage lesion estimated by arthroscopic surgery was 3.5 cm2 (standard deviation [SD] = 1.7) whereas in the open surgery the mean area was 3.2 cm2 (SD = 1.5). The mean difference was 0.3 cm2, indicating a tendency toward overestimation by the arthroscopic evaluation, but the difference was not significant (P = 0.09). Additional MRI assessment of the area demonstrated a mean area of 2.3 cm2 (SD = 1.6). This underestimated the size of the lesion by 1.2 cm2 (SD = 0.8; P = 0.015). Conclusion: Knee arthroscopic examination estimated a cartilage fullthickness lesion with an error of less than 25 % in the majority of the patients.

• Årøen, Asbjørn; Sivertsen, Einar; Owesen, Christian; Engebretsen, Lars & Granan, Lars-Petter (2013). An isolated rupture of the posterior cruciate ligament results in reduced preoperative knee function in comparison with an anterior cruciate ligament injury. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  21(5), s 1017- 1022 . doi: 10.1007/s00167-012-2132-1
• Heir, Stig; Årøen, Asbjørn; Løken, Sverre Bertrand; Holme, Ingar Morten K; Engebretsen, Lars & Reinholt, Finn P. (2012). Cartilage repair in the rabbit knee: mosaic plasty resulted in higher degree of tissue filling but affected subchondral bone more than microfracture technique : a blinded, randomized, controlled, long-term follow-up trial in 88 knees. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  20(2), s 197- 209 . doi: 10.1007/s00167-011-1596-8 Vis sammendrag

  Purpose Discrepancies and variances in outcome following different surgical techniques for cartilage repair are poorly understood. Successful repair relies on proper tissue filling without initiating degenerative processes in the cartilage–bone unit. Consequently, the objective of the current study was to compare two available techniques for cartilage repair, i.e., microfracture technique and mosaic plasty, regarding tissue filling and subchondral bone changes in an experimental model. Methods A 4-mm pure chondral defect was created in the medial femoral condyle of both knees in New Zealand rabbits, aged 22 weeks. A stereomicroscope was used to optimize the preparation of the defects. In one knee (randomized), the defect was treated with microfracture technique whereas in the other with mosaic plasty. The animals were killed at 12, 24 and 36 weeks after surgery. Defect filling, new bone formation above the level of the tidemark and the density of subchondral mineralized tissue were estimated by histomorphometry. Results Mosaic plasty resulted in a significantly 34% higher degree of tissue filling than microfracture technique at 36 weeks, SD of mean difference being 34%. Mosaic plasty resulted in significantly more new bone formation and reduced subchondral mineralized tissue density compared to microfracture technique. The differences between the two techniques were apparent mainly at the long-term follow-up. Conclusion Tissue filling is a limiting factor regarding microfracture technique when compared to mosaic plasty, whereas mosaic plasty resulted in more bone changes than microfracture technique—the implications of the latter remain to be settled. This study underlines the difficulty in predicting outcome in the single case with any of these two techniques, particularly in a long-term perspective. Level of evidence II.

Se alle arbeider i Cristin

• Birkenes, Thomas; Furnes, Ove; Årøen, Asbjørn; Solheim, Eirik; Knutsen, Gunnar; Drogset, Jon Olav; Løken, Sverre Bertrand; Engebretsen, Lars; Lygre, Stein Håkon Låstad & Visnes, Håvard (2020). Langtidsresultater etter fokal bruskskade i kne, In Ann Kristin Hansen (ed.),  Høstmøteboka 2020.  Norsk Ortopedisk Forening.  ISBN 978-82-994275-2-4.  Abstract.  s 33
• Kjennvold, Stian; Randsborg, Per-Henrik; Jakobsen, Rune Bruhn & Årøen, Asbjørn (2020). Fiksasjon av akutte chondrale frakturer i kne, I: Ann Kristin Hansen (red.),  Høstmøteboka 2020.  Norsk Ortopedisk Forening.  ISBN 978-82-994275-2-4.  Abstract.  s 31
• Årøen, Asbjørn (2020). Fixation of acute chondral fractures in adolescent knees.
• Straume-Næsheim, Truls Martin; Persson, Andreas & Årøen, Asbjørn (2019). Patellainstabilitetsregister – noe å bruke tid og resurser på?.
• Wang, Katherine; Esbensen, Qin Ying; Karlsen, Tommy Aleksander; Årøen, Asbjørn & Jakobsen, Rune Bruhn (2019). Low-input RNA-sequencing in patients with cartilage lesions, osteoarthritis, and healthy cartilage - a reference for tissue engineering.
• Årøen, Asbjørn (2019). Cartilages injuries to the knee- The ultimate challenge for the orthopedic surgeon.
• Årøen, Asbjørn; Kjennvold, Stian; Brinchmann, Jan E.; Randsborg, Per-Henrik; Reinholt, Finn P. & Engebretsen, Lars (2019). Bone marrow derived mesenchymal stem cells in a human clinical trial to repair articular cartilage defects of the knee.
• Aae, Tommy Frøseth; Lian, Øystein Bjerkestrand; Årøen, Asbjørn & Randsborg, Per-Henrik (2018). Pasienterstatning etter bruskkirurgi i kneleddet i Skandinavia fra 2010 til 2015.
• Ulstein, Svend; Årøen, Asbjørn; Forssblad, Magnus; Engebretsen, Lars & Røtterud, Jan H (2018). Effect of concomitant cartilage lesions on patient-reported outcome after ACL-reconstruction – a nationwide cohort study from Norway and Sweden of 8,470 patients with 5-Year follow-up.
• Ulstein, Svend; Årøen, Asbjørn; Forssblad, Magnus; Engebretsen, Lars & Røtterud, Jan H (2018). Effect of concomitant cartilage lesions on patient-reported outcome after ACL-reconstruction - a nationwide cohort study from Norway and Sweden of 8470 patients with 5-year follow-up. Orthopaedic Journal of Sports Medicine (OJSM).  ISSN 2325-9671.  6(7) . doi: 0.1177/2325967118S00058
• Årøen, Asbjørn (2018). OCD: an unsolved puzzle in articular cartilage problems. Osteoarthritis and Cartilage.  ISSN 1063-4584.  s 1- 2 . doi: 10.1016/j.joca.2018.09.008
• Årøen, Asbjørn & Devitt, Brian M. (2018). Penny-wise and pound-foolish. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  26(4), s 985- 988 . doi: 10.1007/s00167-018-4852-3
• Årøen, Asbjørn; Kjennvold, Stian; Brinchmann, Jan E.; Randsborg, Per-Henrik; Reinholt, Finn P. & Engebretsen, Lars (2018). Bone marrow derived mesenchymal stem cells in a human clinical trial to repair articular cartilage defects of the knee.
• Aae, Tommy Frøseth; Randsborg, Per-Henrik; Lurås, Hilde; Årøen, Asbjørn & Lian, Øystein Bjerkestrand (2017). MIKROFRAKTUR VERSUS AUTOLOG CHONDROCYTTIMPLANTASJON – EN KOSTNADSEFFEKTIV ANALYSE.
• Owesen, Christian & Årøen, Asbjørn (2017). Symptoms, diagnosis and outcomes in PCL injuries.
• Ulstein, Svend; Årøen, Asbjørn; Forssblad, Magnus; Engebretsen, Lars; Lygre, Stein Håkon Låstad & Røtterud, Jan H (2017). ACL-rekonstruksjon i knær med ledsagende bruskskade - en landsomfattende kohortestudie fra Norge og Sverige med 8470 pasienter med 5 års oppfølging.
• Ulstein, Svend; Årøen, Asbjørn; Forssblad, Magnus; Engebretsen, Lars; Lygre, Stein Håkon Låstad & Røtterud, Jan H (2017). ACL-rekonstruksjon i knær med ledsagende bruskskade - en landsomfattende kohortestudie fra Norge og Sverige med 8470 pasienter med 5-års oppfølging, In Karl-Ivar Lorentzen (ed.),  Høstmøteboken - Vitenskapelig program og abstract 2017.  Norsk ortopedisk forening.  Abstract.  s 201
• Ulstein, Svend; Årøen, Asbjørn; Forssblad, Magnus; Engebretsen, Lars; Lygre, Stein Håkon Låstad & Røtterud, Jan H (2017). Effekt av mikrofraktur eller debridement av ledsagende dyp bruskskade ved ACL-rekonstruksjon - en landsomfattende kohortestudie fra Norge og Sverige med 368 pasienter med 5-års oppfølging, I: Karl-Ivar Lorentzen (red.),  Høstmøteboken - Vitenskapelig program og abstract 2017.  Norsk ortopedisk forening.  Abstract.  s 196
• Ulstein, Svend; Årøen, Asbjørn; Forssblad, Magnus; Engebretsen, Lars; Lygre, Stein Håkon Låstad & Røtterud, Jan H (2017). Effekt av mikrofraktur eller debridement av ledsagende dyp bruskskade ved ACL-rekonstruksjon - en landsomfattende kohortestudie fra Norge og Sverige med 368 pasienter med 5-års oppfølging.
• Årøen, Asbjørn (2017). CORR Insights: High interspecimen variability in engagement of the anterolateral ligament: An in vitro cadaveric study. Clinical Orthopaedics and Related Research.  ISSN 0009-921X.  475(10), s 2445- 2446 . doi: 10.1007/s11999-017-5416-4
• Ulstein, Svend; Bredland, Karin; Årøen, Asbjørn; Engebretsen, Lars & Røtterud, Jan H (2016). No negative effect on patient-reported outcome of cartilage lesions 5-9 years after ACL-reconstruction.
• Ulstein, Svend; Bredland, Karin; Årøen, Asbjørn; Engebretsen, Lars & Røtterud, Jan H (2016). No negative effect on patient-reported outcome of cartilage lesions 5-9 years after ACL-reconstruction. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  24, s S340- S341
• Årøen, Asbjørn (2016). Utfordringer ved bruskkirurgi.
• Engen, Cathrine Nørstad; Løken, S; Årøen, Asbjørn & Engebretsen, Lars (2015). Elleve år gamle fokale bruskskader i knær, bedømt med dgemric. Vis sammendrag

  Innledning: Den naturlige utviklingen av fokale bruskskader i knærne er uavklart. Ikke-kirurgisk behandlede pasienter og pasienter som har gjennomgått bruskkirurgi har tilsvarende langtidsresultater. Resultatene fra kliniske studier innen bruskkirurgi er sprikende. For å avdekke prognostiske faktorer som fører til økt bruskdegenerasjon/artrose på sikt, trenger vi metoder for å vurdere tidlige degenerative forandringer. Prognostiske faktorer kan være etiologi, størrelse, dybde eller lokalisasjon av defekten, pasientens alder, BMI eller aktivitetsnivå eller ulike behandlingsteknikker. Det har vært en stor utvikling innen MR-teknikker de siste tiårene, og man kan nå vurdere innholdet i og kvaliteten av leddbrusk. Målet med denne studien er å evaluere bruskkvaliteten 11 år etter diagnostiserte fokale bruskdefekter i knær. Materialer og metode: Pasientene ble inkludert fra en kohorte av pasienter som ble artroskopert i 1999. Vi inkluderte pasienter med fulltykkelses fokale bruskskader som var under 50 år ved baseline, ikke hadde totalrupturerte ligamenter og minst 50 % av meniskene intakt. Vi inkluderte både pasienter som ble behandlet med avansert bruskkirurgi og pasienter som ikke gjennomgikk ikke-kirurgisk behandling. Evalueringen ble gjort med dGEMRIC, en MR-metode som kvantifiserer innholdet av glykosaminoglykaner og dermed avdekker tidlige artroseforandringer i leddbrusk. Vi registrerte subjektive scorer for vurdering av symptomer og knefunksjon, og røntgenbilder for vurdering av langtkomne artroseforandringer. Resultater: 42 pasienter matchet inklusjonskriteriene og 21 samtykket til deltagelse. Resultatene fra dGEMRIC varierte og demonstrerte både knær med normal leddbrusk og knær med etablert artrose. Vi fant en ikke-signifikant lavere score i dGEMRIC-index når den opprinnelige skaden befant seg på mediale femurkondyl. Vi fant ingen forskjell i knær som ble behandlet med kirurgi sammenlignet med ikke-kirurgi. Totalt sett var de subjektive scorene gode. Ni pasienter hadde Lysholm score over 70. Median KOOS score for sport var 45 og 56 for livskvalitet. Diskusjon: Vi fant varierende resultater i bruskkvalitet og ingen signifikant forskjell mellom kirurgi og ikke-kirurgi. Vi hadde imidlertid få pasienter og det er en sannsynlig seleksjonsbias mellom pasienter som gjennomgikk kirurgi sammenlignet med ikke-kirurgi. Noen pasienter klarer seg fint uten avansert bruskkirurgi, både vurderte med subjektive score og med dGEMRIC. Betydning: Kirurgi er kanskje ikke rett for alle pasienter, og vi må identifisere de som får best utfall med aktiv rehabilitering. Resultatene tyder på at det er behov for en mer systematisk kartlegging for å identifisere prognostiske faktorer hos pasienter med fokale bruskskader. dGEMRIC kan være et nyttig verktøy i arbeidet med å avdekke hvordan kirurgisk og ikke-kirurgisk behandling påvirker utfallet. Dette vil bidra til å skreddersy behandlingen av disse pasientene og dermed utsette, eller unngå, redusert knefunksjon og artrose.

• Engen, Cathrine Nørstad; Løken, Sverre Bertrand; Årøen, Asbjørn & Engebretsen, Lars (2015). Elleve år gamle fokale bruskskader i knær, bedømt med dgemric. Norsk idrettsmedisin.  ISSN 0806-9328.  30(3), s 43
• Engen, Cathrine Nørstad; Løken, Sverre Bertrand; Årøen, Asbjørn & Engebretsen, Lars (2015). Elleve år gamle fokale bruskskader i knær, bedømt med dgemric.
• Owesen, Christian; Sandven-Thrane, Stine; Lind, M; Forssblad, M; Granan, Lars-Petter & Årøen, Asbjørn (2015). Epidemiology surgically treated posterior cruciate ligament injuries in Scandinavia. Vis sammendrag

  Innledning: Bakre korsbånd (PCL) er kneets sterkeste ligament og hindrer i hovedsak posterior translasjon av tibia i forhold til femur, men PCL har også en sekundær stabiliserende funksjon. Det er stor variasjon i rapportert insidens av og årsak til PCL-skader. Det er også uoverensstemmelse i litteraturen når det gjelder forekomst av ledsagende skader. Hensikten med denne studien var å gi en oversikt over skademekanismer, ledsagende skader og andre epidemiologiske data for PCL-skader i de skandinaviske kneligamentregistrene. Materialer og Metoder: Totalt 1287 pasienter som gikk gjennom PCL-rekonstruksjon fra 2004-2013 i de Skandinaviske landene ble inkludert fra de nasjonale ligamentregistrene. Variablene alder, kjønn, aktivitet og graft benyttet ved rekonstruksjon ble samlet inn. Deretter ble skadene sortert basert på ledsagende skader. Til slutt ble data fra de forskjellige landene sammenliknet. Resultater: Pasientenes gjennomsnittsalder var 32.7 år. Kjønnsfordelingsratio var mann kvinne 66.7 %:33.3 %. Avhengig av definisjon var 26-37 % av de behandlede skadene isolerte skader. PCLskader var oftest forekommende i idrett med 35.4 % av det totale antallet PCL-skader. Fotball var den idretten med høyest antall skader (13.1 %). Minimum ett annet ligament var skadet hos 62.2 %. 26.1 % av PCL-skadene hadde en ledsagende bruskskade, 21.0 % hadde meniskskade. Hamstring autograft var det graftet som ble benyttet hyppigst ved rekonstruksjon. Diskusjon: Om lag 1/3 av PCL-skadene er isolerte skader, og er derfor klinisk viktig. Dette er ny informasjon når det gjelder kneligamentskader. Det er høy prevalens av ledsagende brusk- og meniskskader assosiert med PCL-skader, spesielt der minst ett annet ligament også er skadet. Dette kan muligvis forklares ut fra skademekanisme, men dette er fremdeles usikkert. Idrett er den aktivitet som oftest forårsaker PCL-skader som behandles kirurgisk. Dette er i kontrast til den tradisjonelle oppfatningen at PCL-skader forårsakes av dashboard-traume i bilulykker. Det er noen forskjeller i aktiviteter som fører til PCL-skade i de forskjellige landene, og forskjellene kan for en stor del tilskrives antallet utøvere av de forskjellige idrettene. Betydning/Relevans: Grunnleggende kunnskap mangler når det gjelder etiologien til PCL-skader og ledsagende skader. Dette gjør det vanskelig å vurdere hvor representativt materialet som publiseres i ulike ortopediske journaler i virkeligheten er. Epidemiologiske data er en nødvendig del av skadeforebygging i fremtiden. Prevalensen av ledsagende skader er avgjørende for valg av kirurgisk prosedyre og for de forventede resultatene etter kirurgi. De senere år er stadig flere PCL-skader behandlet kirurgisk. Denne studien sikter på å dekke huller i den eksisterende litteraturen ettersom de skandinaviske registrene inneholder et relativt stort antall PCL-skader. Det store antallet gjør det mulig å analysere skademekanismer og ledsagende skader.

• Owesen, Christian; Sandven-Thrane, Stine; Lind, Martin; Forssblad, Magnus; Granan, Lars-Petter & Årøen, Asbjørn (2015). Epidemiology of surgically treated posterior cruciate ligament injuries in scandinavia. Norsk idrettsmedisin.  ISSN 0806-9328.  30(3), s 43 . doi: 10.1007/s00167-015-3786-2
• Owesen, Christian; Sandven-Thrane, Stine; Lind, Martin; Forssblad, Magnus; Granan, Lars-Petter & Årøen, Asbjørn (2015). Epidemiology of surgically treated posterior cruciate ligament injuries in scandinavia.
• Owesen, Christian; Sivertsen, Einar; Engebretsen, Lars; Granan, Lars-Petter & Årøen, Asbjørn (2015). Patients With An Isolated PCL Injury Improve As Much As The ACL Patients From Surgery Measured By KOOS After 2 Years. Orthopaedic Journal of Sports Medicine (OJSM).  ISSN 2325-9671.  3(7) . doi: 10.1177/2325967115S00072
• Owesen, Christian; Sivertsen, Einar; Engebretsen, Lars; Granan, Lars-Petter & Årøen, Asbjørn (2015). Patients with an isolated PCL injury improve as much as the ACL patioens from surgery measured by KOOS after 2 years.
• Røtterud, Jan H; Sivertsen, Einar; Forssblad, M; Engebretsen, Lars & Årøen, Asbjørn (2015). Effect on patient-reported outcome of debridement or microfracture of concomitant full-thickness cartilage lesions in anterior cruciate ligament reconstructed knees: a nationwide cohort study from Norway and Sweden of 357 pasients with 2-year-follow-up..
• Røtterud, Jan H & Årøen, Asbjørn (2015). Focal cartilage lesions in anterior cruciate ligament-injured knees. Series of dissertations submitted to the Faculty of Medicine, University of Oslo. ?.
• Straume-Næsheim, Truls Martin; Mikaelsen, JR; Sivertsen, EA; Devitt, Brian M.; Brand, J; Granan, Lars-Petter & Årøen, Asbjørn (2015). Symptomer og funksjon hos pasienter med residiverende patellaluksasjon sammenlignet med pasienter med fremre korsbåndskade. Vis sammendrag

  Innledning: Patellaluksasjon er en betydelig kneskade med høyest forekomst i alderen 10-17 år. Opp mot 40 % av disse får vedvarende plager med re-dislokasjoner og vedvarende frykt for nye hendelser. Dette gjør at de ikke stoler på kneet og det er en følelse de deler med pasienter som har røket fremre korsbånd. Den siste gruppen har tradisjonelt fått mer fokus i og denne studien ønsket derfor å sammenligne symptomene hos de med residiverende patellaluksasjon med korsbåndpasienter som er satt opp til korsbåndrekonstruksjon. Materialer og metoder: Patellaluksasjonsgruppen bestod av pasienter med to eller flere unilaterale patellaluksasjoner som var søkt inn til rekonstruksjon av mediale patellofemorale ligament (MPFL) fra mai 2010 til mai 2014. Hver av disse ble matchet etter alder, kjønn, og BMI med to pasienter fra Korsbåndregisteret (ACL). Preoperativ Knee injury and Osteoarthritis Outcome Score (KOOS) ble brukt for å vurdere og funksjon for begge grupper. Gruppene ble også sammenlignet i forhold til forekomst av bruskskader og tid fra skade til operasjon. Resultater: I alt 33 pasienter (10 menn og 23 kvinner, snittalder 18,9 (SD=5,0)) ble inkludert i MPFL gruppen. Disse ble matchet med 66 ACL pasienter. MPFL-gruppen hadde signifikant lavere resultat enn ACL gruppen for de tre første underkategoriene av KOOS (MPFL/ACL); smerte; 72,1/80,7 (p=0,021), symptomer; 68,3/79,2 (p<0,01) og daglige aktiviteter; 83,3/90,3 (p<0,01). De laveste resultatene for KOOS var for underkategoriene sport; 51,4/54,5 og livskvalitet; 37,5/38,4, men her var det ingen forskjell mellom MPFL og ACL gruppen. I MPFL-gruppen hadde 36,4 % bruskskade ved operasjonstidspunktet mens tilsvarende tall for ACL-gruppen var kun 7,6 % (p<0,001). Samtidig var gjennomsnittstiden fra første skade til operasjon 32,5 måneder for MPFL-gruppa mot 6,5 måneder for ACL-gruppen. Diskusjon og klinisk relevans: Pasienter med residiverende patellaluksajsoner er like plaget funksjonelt og oppgir mer smerter enn pasienter med sviktende knefunksjon som følge av fremre korsbåndsskade. Patelaluksasjonsgruppen har også 5 ganger så hyppig bruskskade ved operasjonstidspunktet og man venter i snitt 5 ganger så lenge med operasjon fra første skadetidspunkt sammenlignet med de med korsbåndskade

• Årøen, Asbjørn (2015). Hvorfor er ACL revisjon vanskelig?.
• Årøen, Asbjørn (2015). What adjuncts can improve microfracture (stem cells, Scaffolds, PRP)?.
• LaPrade, Robert; Kennedy, Nicholas I.; Goldsmith, Mary; Michalski, Max P.; Devitt, Brian M.; Årøen, Asbjørn; Engebretsen, Lars & Wijdicks, Coen A. (2014). Kinematic analysis of the posterior cruciate ligament; the individual and collective function of the anterolateral and posteromedial bundles.
• LaPrade, Robert; Kennedy, Nicholas I.; Goldsmith, Mary; Michalski, Max P.; Devitt, Brian M.; Årøen, Asbjørn; Engebretsen, Lars & Wijdicks, Coen A. (2014). Kinematic analysis of the posterior cruciate ligament; the individual and collective function of the anterolateral and posteromedial bundles. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  22, s S88
• Sivertsen, Einar; Wagner, LR; Lind, M; Granan, Lars-Petter; Skråmm, Inge & Årøen, Asbjørn (2014). Infeksjon etter ACL rekonstruksjon. Data fra de norske og danske korsbåndregistrene.
• Ulstein, Svend; Bredland, K; Årøen, Asbjørn; Engebretsen, Lars & Røtterud, Jan H (2014). Ingen negativ effekt av fulltykkelse bruskskade hos fremre korsbånd rekonstruerte pasienter ved 5-9 års oppfølging.
• Ulstein, Svend; Årøen, Asbjørn; Røtterud, Jan H; Engebretsen, Lars & Heir, Stig (2014). Microfracture technique versus osteochondral autologous transplantation mosaicplasty in patients with articular chondral lesions of the knee. A prospective randomized trial with long-term follow-up.
• Ulstein, Svend; Årøen, Asbjørn; Røtterud, Jan H; Løken, Sverre Bertrand; Engebretsen, Lars & Heir, Stig (2014). Microfracture technique versus osteochondral autologous transplantation mosaicplasty in patients with articular chondral lesions of the knee. A prospective randomized trial with long-term follow-up. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  22, s S69- S70 . doi: 10.1007/s00167-014-2843-6
• Årøen, Asbjørn (2014). Diagnostikk, testing og operasjonsindikasjoner.
• Årøen, Asbjørn (2014). Siste nytt om bakre korsbåndskader - Singel eller double bundle kirurgi?.
• Årøen, Asbjørn (2014). The infected ACL reconstructed knee - Introduction (epidemiology, incidence).
• Årøen, Asbjørn; Brøgger, Helga Marie; Røtterud, Jan H; Sivertsen, Einar; Engebretsen, Lars & Risberg, May Arna (2014). Evaluation of surrounding articular cartilage in 28 patients knees with a focal cartilage lesion of the knee: using MRI T2 mapping and delayed gadolinium enhanced MRI of cartilage (dGEMRIC).
• Årøen, Asbjørn; Brøgger, Helga Marie; Røtterud, Jan H; Sivertsen, Einar; Engebretsen, Lars & Risberg, May Arna (2014). Evaluation of surrounding articular cartilage in 28 patients knees with a focal cartilage lesion of the knee: using MRI T2 mapping and delayed gadolinium enhanced MRI of cartilage (dGEMRIC). Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  22, s S78- S79
• Owesen, Christian & Årøen, Asbjørn (2013). Isolated PCL injuries and knee cartilage analysis.
• Ulstein, Svend & Årøen, Asbjørn (2013). Focal cartilage lesion in the knee joint. A validation of the ICRS classification system.
• Ulstein, Svend; Årøen, Asbjørn; Røtterud, Jan H; Løken, Sverre Bertrand; Engebretsen, Lars & Heir, Stig (2013). Microfracture technique vs mosaic plasty - No difference in knee scores at 5-11 years follow up in a prospective randomized clinical trial.
• Årøen, Asbjørn (2013). An approach to PCL injuries.
• Årøen, Asbjørn (2013). Epidemiology of cartilage injury and early osteoarthritis.
• Årøen, Asbjørn (2013). Stamceller eller chondrycytter.
• Årøen, Asbjørn (2013). Ulike teknikker, muligheter i fremtiden.
• Årøen, Asbjørn & Verdonk, Peter (2013). Posterior cruciate ligament, exploring the unknown. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  21(5), s 996- 997 . doi: 10.1007/s00167-013-2440-0
• Engebretsen, Lars & Årøen, Asbjørn (2012). Pillars of Esska : Interviewing Prof. Lars Engebretsen by Asbjørn Årøen. Esska Newsletter.  (May), s 10- 10
• Mikaelsen, J; Skråmm, I.; Evensen, Birte; Pedersen, Sarah; Brand, J & Årøen, Asbjørn (2012). Knee function in patients with two or more episodes of patella dislocations.
• Mikaelsen, JR; Skråmm, I.; Evensen, BV; Pedersen, S; Brand, J & Årøen, Asbjørn (2012). Knee function in patients with two or more episodes of patella dislocations. Knee Surgery, Sports Traumatology, Arthroscopy.  ISSN 0942-2056.  20, s S285- S286
• Randsborg, Per-Henrik; Gulbrandsen, Pål; Sivertsen, Einar Andreas; Hammer, Ola-Lars; Fuglesang, Hendrik Frølich & Årøen, Asbjørn (2012). Bruddrater ved fysisk aktivitet hos barn, I: Person Ukjent (red.),  Høstmøteboken 2012 - Høstmøtet Norsk ortopedisk forening.  Norsk ortopedisk forening.  Abstract.  s 190 - 190
• Randsborg, Per-Henrik; Årøen, Asbjørn & Gulbrandsen, Pål (2012). Fractures in Children. Aspects on health service, epidemiology and risk factors. Series of dissertations submitted to the Faculty of Medicine, University of Oslo. 1343.

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