Thomas Birkenes

Background: Concomitant medial collateral ligament (MCL) injury is common in anterior cruciate ligament (ACL) tears, but optimal management of these injury components remains controversial. Purpose: To compare patient-reported outcome measures and the risk of ACL revision surgery in patients with concomitant MCL injuries (treated operatively and nonoperatively) versus isolated ACL injuries and to assess whether MCL treatment strategy or ACL graft choice influenced outcomes. Study Design: Cohort study; Level of evidence 3. Methods: Data were obtained from the Norwegian Knee Ligament Register. Patients undergoing primary ACL reconstruction (ACLR) between 2004 and 2024 were included for graft-survival analyses, and those operated by December 31, 2022, were eligible for 2-year Knee injury and Osteoarthritis Outcome Score (KOOS) outcomes. Patients with concomitant ligament injuries other than to the MCL, ACL repairs, or those with unknown ACL graft type were excluded. Patients were stratified into isolated ACL and ACL + MCL injury groups. Kaplan-Meier survival analyses (unadjusted), multivariable Cox regression, and linear/logistic regression models were used, adjusted for descriptive data, body mass index, meniscal/cartilage injury, time to surgery, smoking, pivoting sports, graft choice, and baseline KOOS. Results: A total of 35,139 ACLRs were included (2410 ACL + MCL and 32,729 isolated ACL; mean age, 28.6 years). Concomitant MCL injury was not associated with an increased overall risk of ACL revision ( P = .5). However, ACL + MCL patients had lower 2-year KOOS Sport/Recreation (Sport/Rec) scores (−2 points, P = .04) and lower odds of achieving patient acceptable symptom state (PASS) for Sport/Rec. Within the ACL + MCL subgroup, hamstring (Hazard ratio [HR], 2.3; P = .001) and quadriceps autografts (HR, 3; P = .009) were associated with a higher revision risk compared with bone-patellar tendon-bone (BPTB) autograft, particularly when hamstring grafts were combined with nonoperative MCL treatment (HR, 2.4; P = .001). Graft choice did not influence the likelihood of achieving a minimal clinically important difference in KOOS. Conclusion: Concomitant MCL injury did not increase the risk of ACL revision but was associated with inferior KOOS Sport/Rec outcomes and lower odds of achieving PASS at 2 years. In patients with concomitant nonoperatively treated MCL injuries, BPTB autograft was associated with a significantly lower revision risk compared with hamstring and quadriceps autografts.

Purpose: There is a paucity of studies reporting patient acceptable symptom state (PASS) thresholds for patient reported outcome measures validated for patellar instability. The aim of this study was to determine the PASS threshold for the Banff Patellofemoral Instability Instrument 2.0 (BPII) following surgery for recurrent patellar instability.Methods: Patients who underwent patellar stabilisation surgery between 2013 and 2022 were included if they were ≥16 years of age and had ≥12 months of follow‐up. The participants completed the BPII and a dichotomous PASS anchor question. The PASS threshold was then calculated using both the adjusted predictive modelling method and receiver operating characteristic (ROC) analysis.Results: Complete data were available for 218 knees of 182 patients, with a median follow‐up time of 46 months. The PASS threshold was 62.4 (95% confidence interval [CI]: 58.8–65.9) using the adjusted predictive modelling method, and 66.3 (95% CI: 58.1–80.0) using ROC analysis. Overall, 173 patients (79.4%) reported satisfactory symptom states, while 72.9% and 70.6% achieved the respective PASS thresholds. The adjusted predictive modelling method yielded narrower 95% confidence intervals with minimal threshold variation across different approaches for handling bilateral cases compared to ROC analysis (1.3 vs. 8.1 points).Conclusion: The PASS threshold for BPII after patellar stabilisation surgery was 62.4 (out of 100 points). The adjusted predictive modelling method demonstrated superior precision and robustness in the PASS threshold calculation compared with the ROC analysis. This threshold provides a disease‐specific reference for clinical decision making and research in patellofemoral instability.Level of Evidence: Level III.

Background: Knee cartilage injuries can lead to significant functional limitations, pain, and diminished quality of life. Microfracture (MF) is the most common surgical procedure for smaller (2 ) cartilage lesions of the knee. However, there is no established gold-standard surgical intervention. Purpose: To compare functional and patient-reported outcomes after MF and arthroscopic debridement (AD) for symptomatic, isolated femoral cartilage injuries 2 in patients aged 18 to 50 years. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 65 patients were included, randomized to undergo either MF (n = 31) or AD (n = 34), and followed for 2 years. The primary outcome was the change in the Knee injury and Osteoarthritis Outcome Score (KOOS) Quality of Life subscore. Secondary outcomes included scores for the other KOOS subscales, Tegner activity scale, Lysholm score, and visual analog scale for pain. Results: The mean age at the time of inclusion was 33.2 ± 9.7 years. There were 44 (68%) male patients. The mean size of the lesion was 1.2 ± 0.6 cm ² . There was no statistically significant difference between the groups in the change in the KOOS Quality of Life subscore from baseline to 2 years (3.5 [95% CI, –10.0 to 16.9]; P = .61). There were 10 complications in 5 patients in the MF group and 2 complications in 2 patients in the AD group. According to a linear mixed model, there were no statistically significant differences between the groups for any of the secondary outcomes at any time point during the 2-year follow-up period. Conclusion: MF was not superior to AD when treating femoral cartilage lesions of the knee 2 .

Background: Focal cartilage lesions (FCLs) are frequently found during knee arthroscopies and may impair quality of life (QoL) significantly. Several treatment options with good short-term results are available, but the natural history without any treatment is largely unknown. The aim of this study was to evaluate patient-reported outcome measures (PROMs), the need for subsequent cartilage surgery, and the risk of treatment failure 20 years after diagnosis of an FCL in the knee. Methods: Patients undergoing any knee arthroscopy for an FCL between 1999 and 2012 in 6 major Norwegian hospitals were identified. Inclusion criteria were an arthroscopically classified FCL in the knee, patient age of ≥18 years at surgery, and any preoperative PROM. Exclusion criteria were lesions representing knee osteoarthritis or “kissing lesions” at surgery. Demographic data, later knee surgery, and PROMs were collected by questionnaire. Regression models were used to adjust for and evaluate the factors impacting the long-term PROMs and risk factors for treatment failure (defined as knee arthroplasty, osteotomy, or a Knee injury and Osteoarthritis Outcome Score-Quality of Life [KOOS QoL] subscore of 1 FCL (OR, 1.9 [CI, 1.1 to 3.3]), a full-thickness lesion (OR, 2.5 [95% CI, 1.3 to 5.0]), and a lower level of education (OR, 1.8 [95% Cl, 1.1 to 2.8]). Autologous chondrocyte implantation (ACI) was associated with significantly higher KOOS QoL, by 17.5 (95% CI, 3.2 to 31.7) points, and a lower risk of treatment failure compared with no cartilage treatment, microfracture, or mosaicplasty. Conclusions: After a mean follow-up of 19 years, patients with an FCL who did not require a subsequent knee arthroplasty had significantly higher PROM scores than preoperatively. Nonsurgical treatment of FCLs had results equal to those of the surgical FCL treatments except for ACI, which was associated with a better KOOS and lower risk of treatment failure. Full-thickness lesions, >1 FCL, a lower level of education, and a greater BMI were the main risk factors associated with poorer results. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Purpose: The hypothesis of the present study assumed that a history of focal cartilage lesions would not affect Knee Injury and Osteoarthritis Outcome scores (KOOSs) following knee arthroplasty compared to a matched national cohort of knee arthroplasty patients.Methods: Fifty‐eight knee arthroplasty patients with previous surgery for focal cartilage lesions (cartilage cohort) were compared to a matched cohort of 116 knee arthroplasty patients from the Norwegian Arthroplasty Register (control group). Age, sex, primary or revision arthroplasty, type of arthroplasty (total, unicondylar or patellofemoral), year of arthroplasty surgery and arthroplasty brand were used as matching criteria. Demographic data and KOOS were obtained through questionnaires. Regression models were employed to adjust for confounding factors.Results: Mean follow‐up post knee arthroplasty surgery was 7.6 years (range 1.2–20.3) in the cartilage cohort and 8.1 (range 1.0–20.9) in the control group. The responding patients were at the time of surgery 54.3 versus 59.0 years in the cartilage and control group, respectively. At follow‐up the control group demonstrated higher adjusted Knee Injury and Osteoarthritis Outcome subscores than the previous focal cartilage patients with a mean adjusted difference (95% confidence interval in parentheses): Symptoms 8.4 (0.3, 16.4), Pain 11.8 (2.2, 21.4), Activities of daily living (ADL) 9.3 (−1.2, 18.6), Sport and recreation 8.9 (−1.6, 19.4) and Quality of Life (QoL) 10.6 (0.2, 21.1). The control group also demonstrated higher odds of reaching the patient‐acceptable symptom state threshold for the Knee Injury and Osteoarthritis Outcome subscores with odds ratio: Symptoms 2.7 (1.2, 6.4), Pain 3.0 (1.3, 7.0), ADL 2.1 (0.9, 4.6) and QoL 2.4 (1.0, 5.5).Conclusion: Previous cartilage surgery was associated with inferior patient‐reported outcomes after knee arthroplasty. These patients also exhibited significantly lower odds of reaching the patient‐acceptable symptom state threshold for the Knee Injury and Osteoarthritis Outcome subscores.Level of Evidence: Level III.

Background: Focal cartilage lesions are common in the knee. The risk of later ipsilateral knee arthroplasty remains unknown. The purposes of the present study were to evaluate the long-term cumulative risk of knee arthroplasty after arthroscopic identification of focal cartilage lesions in the knee, to investigate the risk factors for subsequent knee arthroplasty, and to estimate the subsequent cumulative risk of knee arthroplasty compared with that in the general population. Methods: Patients who had undergone surgical treatment of focal cartilage lesions at 6 major Norwegian hospitals between 1999 and 2012 were identified. The inclusion criteria were an arthroscopically classified focal cartilage lesion in the knee, an age of ≥18 years at the time of surgery, and available preoperative patient-reported outcomes (PROMs). The exclusion criteria were osteoarthritis or “kissing lesions” at the time of surgery. Demographic data, later knee surgery, and PROMs were collected with use of a questionnaire. A Cox regression model was used to adjust for and investigate the impact of risk factors, and Kaplan-Meier analysis was performed to estimate cumulative risk. The risk of knee arthroplasty in the present cohort was compared with that in the age-matched general Norwegian population. Results: Of the 516 patients who were eligible, 322 patients (328 knees) consented to participate. The mean age at the time of the index procedure was 36.8 years, and the mean duration of follow-up was 19.8 years. The 20-year cumulative risk of knee arthroplasty in the cartilage cohort was 19.1% (95% CI, 14.6% to 23.6%). Variables that had an impact on the risk of knee arthroplasty included an ICRS grade of 3 to 4 (hazard ratio [HR], 3.1; 95% CI, 1.1 to 8.7), an age of ≥40 years at time of cartilage surgery (HR, 3.7; 95% CI, 1.8 to 7.7), a BMI of 25 to 29 kg/m² (HR, 3.9; 95% CI, 1.7 to 9.0), a BMI of ≥30 kg/m² (HR, 5.9; 95% CI, 2.4 to 14.3) at the time of follow-up, autologous chondrocyte implantation (ACI) at the time of the index procedure (HR, 3.4; 95% CI, 1.0 to 11.4), >1 focal cartilage lesion (HR, 2.1; 95% CI, 1.1 to 3.7), and a high preoperative visual analog scale (VAS) score for pain at the time of the index procedure (HR, 1.1; 95% CI, 1.0 to 1.1). The risk ratio of later knee arthroplasty in the cartilage cohort as compared with the age-matched general Norwegian population was 415.7 (95% CI, 168.8 to 1,023.5) in the 30 to 39-year age group. Conclusions: In the present study, we found that the 20-year cumulative risk of knee arthroplasty after a focal cartilage lesion in the knee was 19%. Deep lesions, higher age at the time of cartilage surgery, high BMI at the time of follow-up, ACI, and >1 cartilage lesion were associated with a higher risk of knee arthroplasty. Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.