Norwegian Knee Ligament Registry Research Articles

Rates of Subjective Failure After Both Isolated and Combined Posterior Cruciate Ligament Reconstruction: A Study From the Norwegian Knee Ligament Registry 2004-2021

Background: Outcomes after posterior cruciate ligament (PCL) reconstruction (PCLR) have been reported to be inferior to those of anterior cruciate ligament reconstruction. Furthermore, combined ligament injuries have been reported to have inferior outcomes compared with isolated PCLR. Purpose/Hypothesis: The purpose of this study was to report on PCLR outcomes and failure rates and compare these outcomes between isolated PCLR and multiligament knee surgery involving the PCL. The hypothesis was that combined PCL injury reconstruction would have higher rates of subjective failure and revision relative to isolated PCLR. Study Design: Cohort study; Level of evidence, 3. Methods: Patients with primary PCLR with or without concomitant ligament injuries registered in the Norwegian Knee Ligament Registry between 2004 and 2021 were included. Knee injury and Osteoarthritis Outcome Score (KOOS) totals were collected preoperatively and at 2 years and 5 years postoperatively. The primary outcome measure was failure, defined as either a revision surgery or a KOOS Quality of Life (QoL) subscale score <44. Results: The sample included 631 primary PCLR procedures, with 185 (29%) isolated PCLR procedures and 446 (71%) combined reconstructions, with a median follow-up time of 7.3 and 7.9 years, respectively. The majority of patients had poor preoperative knee function as defined by a KOOS QoL score <44 (90.1% isolated PCLR, 85.7% combined PCL injuries; P = .24). Subjective outcomes improved significantly at 2- and 5-year follow-up compared with preoperative assessments in both groups (P < .001); however, at 2 years, 49.5% and 46.5% had subjective failure (KOOS QoL <44) for isolated PCLR and combined PCLR, respectively (P = .61). At 5 years, the subjective failure rates of isolated and combined PCLR were 46.7% and 34.2%, respectively (P = .04). No significant difference was found in revision rates between the groups at 5 years (1.9% and 4.6%, respectively; P = .07). Conclusion: Patients who underwent PCLR had improved KOOS QoL scores relative to their preoperative state. However, the subjective failure rate was high for both isolated and multiligament PCLR. Within the first 2 years after surgery, patients who undergo isolated PCLR can be expected to have similar failure rates to patients who undergo combined ligament reconstructions.

The Delaware-Oslo ACL Cohort treatment algorithm yields superior outcomes to usual care 9-12 years after anterior cruciate ligament reconstruction.

Patient-reported outcomes were compared between participants who followed the treatment algorithm of the Delaware-Oslo ACL Cohort, consisting of progressive preoperative and postoperative rehabilitation, patient education, clinical testing and shared decision-making about treatment choice, and those who followed usual care 9-12 years after anterior cruciate ligament reconstruction (ACLR). Participants with primary ACLR were included from the Norwegian arm of the Delaware-Oslo ACL Cohort and the Norwegian Knee Ligament Registry (usual care). The Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale scores and the International Knee Documentation Committee-Subjective Knee Form (IKDC-SKF) scores were compared. KOOS scores for the usual care group were converted to IKDC-SKF scores with recently published validated crosswalk. The percentages of participants with scores above predefined thresholds for patient acceptable symptom state (PASS) were also calculated. Eighty of 100 (80%) participants from the Delaware-Oslo ACL Cohort and 1588 of 3248 (49%) from the usual care group participated in the follow-up. Participants from the Delaware-Oslo ACL Cohort had higher KOOS subscale (p < 0.001) and IKDC-SKF scores (p < 0.001), and a higher percentage reached PASS (84%-96% vs. 62%-76%, p ≤ 0.002) for KOOS Pain, symptoms, activities of daily living and sports compared to the usual care group. No significant differences were found for KOOS quality of life scores (not significant [n.s.]) or PASS percentages (80% vs. 74%, n.s.). Participants with ACLR who followed the Delaware-Oslo ACL Cohort treatment algorithm had reduced knee symptoms, superior function and higher percentages of satisfactory outcomes than participants who followed usual care. Level II.

Recurrent lateral patella dislocation affects knee function as much as ACL deficiency \u2013 however patients wait five times longer for treatment

BackgroundSurgical 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.MethodForty-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.ResultsThe 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.ConclusionRLPD 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.Trial registrationThe patients with RLPD consisted of patients who were examined for possible recruitment for a concurrent prospective randomized controlled trial comparing conservative treatment and isolated surgical medial patellofemoral ligament (MPFL) reconstruction (Clinical trials no: NCT02263807, October 2014).

Re-revision Anterior Cruciate Ligament Reconstruction: An Evaluation From the Norwegian Knee Ligament Registry

To identify the rate of re-revision anterior cruciate ligament reconstruction (ACLR) to estimate the influence of patient-related factors on the risk of re-revision ACLR. The secondary aim of the study was to report the intra-articular findings and patient-related factors at the time of revision ACLR and to compare these with the findings in a matched controlled group of primary ACLR. Patients with primary ACLR without a subsequent need of revision and patients with a revision ACLR identified in the Norwegian Knee Ligament Registry from June 2004 through September 2016 were included. Using age at operation, sex, activity at injury, and year of ACLR as covariates, a propensity score matched control group of primary ACLR patients for the revision ACLR patients was identified. For the revision ACLR patients, re-revision ACLR rates at 1, 2, 5, and 8years were estimated with Kaplan-Meier analysis; the hazard ratio for a re-revision ACLR was estimated using a multivariable Cox regression model. The cumulative estimated proportion of patients undergoing a re-revision ACLR at 1, 2, 5, and 8years after the original revision ACLR was 0.4%, 3.0%, 6.5%, and 9.0% respectively. There was no significant difference between the control and revision ACLR groups regarding cartilage injury (P= .72) or associated ligament injury (P= .17). Revision ACLR patients did have fewer meniscal injuries (P < .001). There were no intraoperative findings or surgical techniques identified as a predictor for a higher risk of re-revision ACLR. Based on a review of a large ligament reconstruction registry,one can expect 9% of patients to undergo a re-revision ALCR at 8years of follow up. Revision ACLR did not have an increase in cartilage injuries or associated ligament injuries and had significantly fewer meniscal injuries compared with a primary ACLR control group. Level III, retrospective comparative study.

No effect of graft size or body mass index on risk of revision after ACL reconstruction using hamstrings autograft.

The current study investigated the distribution of hamstrings graft size and body mass index and any potential effect on the risk of revision surgery in a large prospective cohort of patients undergoing ACL reconstruction. More specifically, the aim of the study was to investigate whether larger graft size or smaller BMI would decrease the risk of revision after ACL reconstruction. A total of 4029 patients, prospectively registered in the Norwegian Knee Ligament Registry, were included in the study. Univariate Kaplan-Meier survival analyses (with log-rank tests) and the Cox proportional hazard (PH) regression model were applied to compare risk of revision between groups of patients. Mutual adjustment for gender, age, activity at the time of injury and fixation method of the graft was performed. Graft sizes spanned from 5.5 to 11.0mm and the median of 8.0mm was reported in 42% of patients in the cohort. BMI was reported from 15 to 57 with a median of 25. 46% of patients were classified as overweight (WHO standards), while 23% of patients were obese. At a median of 2.5years after surgery, 150 patients had undergone revision surgery. Although certain effects were seen in the unadjusted analyses, neither graft size (diameter) nor patient BMI did affect the risk of undergoing revision surgery in the adjusted analyses. Graft size and BMI was not found to be independent risk factors for undergoing ACL revision surgery. In contrast to other studies, graft size of 8mm or larger did not have a better outcome than smaller graft sizes. A relatively large group of overweight patients undergoing ACL surgery reflects the general increase in weight seen in Western societies. Although the current study differs from previous findings, it might indicate that graft diameter is less important than previously stated. Cohort study, II.

Effect of Activity at Time of Injury and Concomitant Ligament Injuries on Patient-Reported Outcome After Posterior Cruciate Ligament Reconstruction.

Background:The outcomes after posterior cruciate ligament reconstruction (PCLR) have been shown to be inferior to those of anterior cruciate ligament reconstruction. There is a lack of knowledge regarding prognostic factors of PCLR outcomes.Purpose:To explore the effect of injury mechanism and concomitant ligament injuries on patient-reported outcomes at 2-year follow-up after PCLR.Study Design:Cohort study; Level of evidence, 2.Methods:A total of 373 patients who underwent primary PCLR and who were registered in the Norwegian Knee Ligament Registry were included. The Knee injury and Osteoarthritis Outcome Score (KOOS) was used as the patient-reported outcome measure. At 2-year follow-up, 252 patients (68%) had completed the KOOS. Multiple regression analysis was used to evaluate the effects of injury activity and multiligament injuries on the KOOS outcomes.Results:In the adjusted and unadjusted regression analyses, patients injured during sports reported significantly better outcome at 2-year follow-up after PCLR than patients injured during other activities (P < .001) according to all KOOS subscales. Adjusted analysis was as follows for the KOOS subscales: Symptoms (regression coefficient [β], 7.0; 95% CI, 1.9-12.2), Pain (β, 13.4; 95% CI, 8.0-18.9), Activities of Daily Living (β, 12.6; 95% CI, 7.1-18.1), Sport/Recreation (β, 15.3; 95% CI, 8.0-22.5), and Quality of Life (β, 13.5; 95% CI, 7.1-20.0). In the unadjusted analysis, patients with isolated PCL injuries reported higher scores in the Sport/Recreation subscale (β, –7.9; 95% CI, –15.5 to –0.3). The difference was not significant in the adjusted analysis. No other significant differences in KOOS outcomes were found between isolated and multiligament injuries.Conclusion:Patients injured in sports reported better outcomes at 2 years after PCLR as compared with patients injured in other activities. Multiligament injuries involving the PCL do not seem to predict a worse outcome than for isolated PCL injuries.

Meaningful Change Scores in the Knee Injury and Osteoarthritis Outcome Score in Patients Undergoing Anterior Cruciate Ligament Reconstruction

Background: Meaningful change scores in the Knee injury and Osteoarthritis Outcome Score (KOOS) in patients undergoing anterior cruciate ligament (ACL) reconstruction have not yet been established. Purpose: To define the minimal important change (MIC) for the KOOS after ACL reconstruction. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: KOOS and anchor questions with 7-point scales ranging from “better, an important improvement” to “worse, an important worsening” were completed postoperatively by randomly chosen participants from the Norwegian Knee Ligament Registry. Presurgery KOOS scores were retrieved from the registry. The MIC for improvement was calculated with anchor-based approaches using the predictive modeling method adjusted for the proportion of improved patients, the mean change method, and the receiver operating characteristic (ROC) method. Results: Complete data for at least one of the KOOS subscales were obtained from 542 (45.3%) participants. Predictive modeling MIC values were 12.1 for the KOOS subscales of Sport and Recreational Function and 18.3 for Knee-Related Quality of Life. These values aid in interpreting within-group improvement over time and can be used as responder criteria when comparing groups. The corresponding and much lower values for the subscales of Pain (2.5), Symptoms (–1.2), and Activities of Daily Living (2.4) are the results from patients reporting, on average, only mild problems with these domains preoperatively. Although 4% to 10% of patients reported subscale-specific worsening, MIC deterioration calculations were not possible. The ROC MIC values were associated with high degrees of misclassification. Values obtained by the mean change method were considered less reliable because these estimates are derived from subgroups of patients. Average KOOS change scores were approximately similar for patients reporting acceptable symptoms postoperatively and patients reporting important improvements on the anchor items after surgery. Conclusion: KOOS users should apply subscale-specific cutoffs for meaningful improvement. Our results confirm using the subscales of Sport and Recreational Function and Knee-Related Quality of Life as primary patient-reported outcomes after ACL reconstruction. The predictive modeling approach gave the most robust estimates of MIC values. Our data suggest that reporting acceptable symptoms postoperatively corresponds to reporting an important improvement after ACL reconstruction.

Outcomes and Predictors of Revision Anterior Cruciate Ligament Reconstruction: An Evaluation of the Norwegian Knee Ligament Registry

Objectives:The Norwegian Ligament Registry (NKLR) provides an opportunity for quality surveillance and research. Intraoperative findings and outcome after revision anterior cruciate ligament reconstruction (RACLR) is not as well studied as after primary ACL reconstruction. There were two objectives of this study. First, to evaluate the Norwegian Knee Ligament Registry (NKLR) for the occurrence, failure rate, graft choice, patient demographic profile (gender, age, body mass index), sport at time of injury and associated pathology (cartilage injuries, meniscal tears, other ligament injuries) for revision anterior cruciate ligament reconstructions (RACLR). Second, to match compare RACLR patients to primary ACL reconstructions in order to define possible predictors for those patients who will require RACLR.Methods:All patients identified in the NKLR from June 2004 until September 2016 that did not undergo cartilage restoration, meniscal transplant nor had a documented fracture at the primary reconstruction were included in the study. Revision rates at 1, 2 and 5 years were estimated with Kaplan-Meier analysis, and the estimated risk of RACLR based upon demographic and associated pathology was estimated with Cox regression analysis.Results:784 patients with an average age of 25.6 years (25.0-26.3) met the inclusion and exclusion criteria with 53.1% being male. 62.1% of revisions were performed with bone patellar bone (BPTB) autograft while 23% used hamstring autograft. Associated injuries of the menisci, cartilage, and other ligaments and the sport at the time of injury are listed (Table 1). 12.9% of RACLR patients went on to have a Re-revision ACLR at 5 years postop (Figure 1). Match comparisons of primary ACLR patients with RACLR demonstrated no significant difference in occurrence based upon age (<20, 20-30, and >30 years), graft choice (BPTB, Hamstring, Allograft, Bone Quadriceps Tendon (BQT)), cartilage injury (No injury, ICRS 1-2, ICRS 3-4), meniscal Injury, associated ligament injury, sport at time of injury or Body Mass Index (BMI).Conclusion:Based upon review of a large ligament reconstruction registry, one can expect that less than 13% of patients undergo a Re-revision ALCR following failure of a RALCR at 5 years. Match comparison of primary ACLR versus RACLR demonstrated no significant predictor of RACLR based upon age, graft choice, cartilage injury, meniscal injury, associated ligament injury, sport or BMI.

Compensation after treatment for anterior cruciate ligament injuries: a review of compensation claims in Norway from 2005 to 2015

PurposeTo assess the most common reasons for complaints following anterior cruciate ligament (ACL) injuries reported to the Norwegian System of Patient Injury Compensation (NPE), and to view these complaints in light of the ACL reconstructions (ACL-Rs) reported to the Norwegian Knee Ligament Registry (NKLR).MethodData from the NPE and the NKLR were collected for the study period (2005–2015). The age and gender and type of complaint and reason for granted compensation were collected from the NPE, while the graft choice and total number of ACL-R were collected from the NKLR. Risk for successful grant was estimated for graft type.Results18,810 primary ACL-Rs were reported to the NKLR during the study period. A hamstring graft was used in 12,437 (66.1%) but the bone-patellar tendon-bone (BPTB) became the graft of choice at the end of the study period. 240 patients filed a complaint to the NPE, of which 101 were granted compensation. The odds ratio for a claim being granted following a hamstring graft was 2.9 compared to that of a BPTB graft (p = 0.002) The most common reason for compensation was a hospital-acquired infection in 39 patients (38.6%) followed by inadequate surgical technique (27, 26.7%) and delayed diagnosis (13, 12.9%). Of the 39 patients with infection, 27 had received a hamstring graft and six a BPTB graft (two patients were not reconstructed, data missing for three patients). Of the 27 patients who were granted compensation due to inadequate surgical technique, 24 had received a hamstring graft and three a BPTB graft.ConclusionInfection and inadequate surgical technique are the most common causes for granted compensation from the NPE following ACL injury. Hamstring grafts have a threefold risk of complication that yields compensation from the NPE compared to BPTB grafts. This information is relevant for patients and surgeons when choosing graft type. The trend of increased use of BPTB grafts is warranted based on the results from this study.Level of evidenceLevel III.

New Trauma is the Most Common Cause of Revision After Primary Anterior Cruciate Ligament Reconstruction – A Study from the Norwegian Knee Ligament Registry 2004-2015

New Trauma is the Most Common Cause of Revision After Primary Anterior Cruciate Ligament Reconstruction – A Study from the Norwegian Knee Ligament Registry 2004-2015

The Effect of Limited Perioperative Nonsteroidal Anti-inflammatory Drugs on Patients Undergoing Anterior Cruciate Ligament Reconstruction

Background: The administration of nonsteroidal anti-inflammatory drugs (NSAIDs) to patients undergoing anterior cruciate ligament reconstruction (ACLR) is controversial because it may impair tissue healing and clinical outcomes. Purpose: To assess the effect of NSAID administration on patients undergoing ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: Included patients were aged >15 years and were registered in the Norwegian Knee Ligament Registry from 2008 until 2013 after the primary ACLR. Patients with insufficient data regarding administration of NSAIDs and those with associated knee ligament injuries requiring surgical treatment were excluded from this study. Graft survival was estimated using Kaplan-Meier survival curves, and hazard ratios (HRs) for revision were evaluated using Cox regression analysis. Logistic regression analysis was used to calculate the odds ratio (OR) for a Knee Injury and Osteoarthritis Outcome Score (KOOS)–quality of life (QOL) subscale score <44 at 2-year follow-up. Results: A total of 7822 patients were included in the analysis for graft survival and assessment for risk of revision. Of these, 4144 patients were administered NSAIDs postoperatively. The mean duration of follow-up was 2.8 years (range, 0-5.9 years). Administration of NSAIDs did not influence graft survival (P = .568). Adjusted Cox regression analyses demonstrated the same finding regarding risk of revision (HR, 1.0; 95% CI, 0.8-1.3). ACLR using a bone–patellar tendon–bone autograft showed a reduced risk of revision (HR, 0.3; 95% CI, 0.1-0.8) among patients administered NSAIDs. In subgroup analyses of 3144 patients, administration of NSAIDs demonstrated a beneficial effect on the risk of a KOOS-QOL score <44 at 2-year follow-up (OR, 0.8; 95% CI, 0.6-0.9). Conclusion: Administration of NSAIDs to patients after ACLR does not have a negative effect on graft survival, risk of revision, or risk of a KOOS-QOL score <44 at 2-year follow-up. We emphasize using caution when administering NSAIDs by keeping the duration and dosage of NSAIDs as short and low as possible to ensure sufficient pain relief while limiting unwanted exposure to any known and unknown adverse effects of these drugs.

Patients With Isolated PCL Injuries Improve From Surgery as Much as Patients With ACL Injuries After 2 Years.

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 = 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 = .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.

Patients With An Isolated PCL Injury Improve As Much As The ACL Patients From Surgery Measured By KOOS After 2 Years

Objectives:Background: Isolated posterior cruciate ligament (PCL) injuries are severe knee injuries, often caused by a sports injury or a traffic accident and can be treated either conservatively (with a brace and exercises) or by reconstructive surgery. Results reported after reconstructive surgery contain a mixture of isolated and combined knee ligament injuries. Consequently the results after such surgery are not documented thoroughly. Hypothesis: Patients undergoing PCL reconstruction demonstrate the same improvements as patients treated with ACL reconstruction measured by Knee Osteoarthritis Outcome Score (KOOS) two years postoperatively.Study Design:The study is a prospective cohort study based on registry data. Evidence level II.Methods:The Norwegian Knee Ligament Registry contains data including patient reported KOOS values on 295 PCL injuries (71 isolated PCL injuries) and some 10.000 ACL injuries registered between 2004 and 2010. The changes in KOOS scores from preoperative values to two years follow up after surgery were compared by paired sample t-test in each of the two patient groups. The main outcome measure was patient reported outcome measured by changes in the KOOS quality of life (QoL) subscale. Then the changes for the PCL patients were compared to the corresponding changes for the ACL patients.Results:The delay to surgery was significantly longer for PCL patients compared to the ACL patients (median 21.5months vs 8.0 months). Most surgeries were performed using single bundle hamstring graft for both PCL and ACL reconstruction. PCL reconstructed patients had an improved patient reported knee function postoperatively measured by KOOS at two years with improvement in all KOOS subscales as follows; Pain: 15.1, CI (8.5-21.8), p<0.01. Symptoms: 0.9, CI (-6.6-8.3), p=0.82. ADL: 13.2, CI (6.6-13.9), p<0.01. Sports: 20.7, CI (11.8-29.4), p<0.01. QoL: 26.6, CI (18.9-34.2), p<0.01. The reported results for the ACL patients were; Pain: 10.5, CI (10.2-11.5), p<0.01. Symptoms: 5.1, CI (4.1-5.2), p<0.01. ADL: 8.1, CI (7.7-8.6), p<0.01. Sports: 23.0 CI (22.2-23.8), p<0.01. QoL: 31.7, CI (31.0-32.4), p<0.01. The increments in KOOS for the PCL patients are similar to those of the ACL patients. For the KOOS subscale pain the improvements was larger than for ACL treated patients but no significant difference was found.Conclusion:Patients undergoing PCL reconstruction with single bundle hamstring graft can expect the same improvements in KOOS as patients undergoing ACL reconstruction. However the PCL patients start out with an average inferior score in all subscales and consequently end up at a lower score compared to the ACL patients for all KOOS subscales.Clinical Relevance:The present study provides relevant information on what results to expect after single bundle PCL reconstruction. PCL reconstructed patients can achieve similar improvements to ACL reconstructed patients measured by KOOS. Improvements in surgical techniques might result in restoration of knee function to the same level as ACL injured knees. Candidates for PCL reconstruction, could be informed about these results during the decision making process. To our knowledge, this study comprises the largest material available on isolated PCL injuries treated with reconstructive surgery.

Outcomes after Anterior Cruciate Ligament Reconstruction using the Norwegian Knee Ligament Registry of 14,142 Patients

Objectives:While the effects of concurrent meniscal resection and anterior cruciate ligament reconstruction (ACLR) are known to decrease patient outcomes and increase the rate of osteoarthritis over the long-term, overall short-term patient functional outcomes in a large cohort of patients are not well known. Therefore, the purpose of this study is to compare the preoperative and two-year postoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale scores after ACLR with and without meniscal injury. In comparison to an isolated ACLR, we hypothesized that patients with a medial meniscal (MM) or lateral meniscal (LM) resection with an ACLR would have significantly decreased two-year postoperative KOOS outcomes, while those with an ACLR with a MM or LM repair would be indistinguishable to isolated ACLR.Methods:The Norwegian Knee Ligament Registry (NKLR) was used to evaluate outcomes for a total of 14,142 patients with primary ACLR. The KOOS scoring system was used to evaluate patients on 5 subscales (Pain, Other Symptoms, Activities of Daily Life (ADL), Sport and Recreation Function (Sport/Rec), and Quality of Life (QoL) at time of surgery and at two-year postoperative follow-up. Patients with isolated ACLR and ACLR with LM repair, LM resection, MM repair or MM resection were compared using multiple linear regression modeling.Results:Preoperatively, in comparison to isolated ACLR, patients that had an ACLR with either a MM repair or MM resection had significantly lower scores for all KOOS subscores and LM repair had significantly decreased scores on the Other Symptoms, Pain, and ADL subscales. Postoperatively, in comparison to isolated ACLR, two-year KOOS outcomes were not significantly different between patients with ACLR and either LM repair, MM resection, or LM resection; however, those with MM repair had significantly lower scores on the Other Symptoms and QoL subscales.Conclusion:For the majority of study groups, patients with meniscal repairs or resections with concomitant ACLR had postoperative KOOS scores that were not significantly different from an isolated ACLR. Patients with ACLR with meniscal resections do not exhibit decreased clinical outcomes at two years postoperatively. It is recommended that clinicians follow patients with ACLR and concurrent meniscal treatment for longer than two years postoperatively.

Proportion of Patients Reporting Acceptable Symptoms or Treatment Failure and Their Associated KOOS Values at 6 to 24 Months After Anterior Cruciate Ligament Reconstruction

Background: The proportion of patients perceiving their symptoms as either acceptable or as a failure of treatment after anterior cruciate ligament reconstruction (ACLR) is unknown. Commonly used outcome scores such as the Knee injury and Osteoarthritis Outcome Score (KOOS) suffer from poor interpretability, and little is known about which scores represent an acceptable or failed postoperative outcome. Purpose: To determine the proportion of patients reporting acceptable symptoms or treatment failure at 6 to 24 months after ACLR and to define KOOS values corresponding to the patients’ perceptions of treatment outcome. Study Design: Cross-sectional study; Level of evidence, 3. Methods: In 2012, a total of 1197 patients were randomly extracted from the Norwegian Knee Ligament Registry at 3 postoperative time points: 397 at 6 months, 400 at 12 months, and 400 at 24 months. The inclusion criterion was unilateral primary ACLR. Questions about acceptable symptoms and treatment failure and the KOOS questionnaire were sent to the patients, and those who answered “yes” to the acceptable symptoms question were considered to have acceptable symptoms. Patients who answered “no” to the same question and “yes” to the treatment failure question were considered to have treatment failure. Mean KOOS values and 95% CIs were calculated for each category. Results: A complete data set was obtained from 598 (50%) responders. Fifty-five percent of the patients perceived their symptoms as acceptable at 6-month follow-up versus 66% at 12- to 24-month follow-up. Similarly, 7% at 6-month follow-up perceived their treatment to have failed versus 12% at 12- to 24-month follow-up. Postoperative mean KOOS subscale values ranged from 72 (95% CI, 70-74) to 95 (95% CI, 94-96) for patients with acceptable symptoms and from 28 (95% CI, 22-34) to 71 (95% CI, 65-76) for patients with treatment failure. For both categories, the worst subscale values were seen in the sport and recreation and quality of life subscales and the best in the activities of daily living subscale. Conclusion: Only half of the patients at 6 months and about two-thirds at 1 to 2 years perceived their symptoms as acceptable after ACLR. For these patients, KOOS values reflected no problems to mild problems on average, while for patients reporting treatment failure, KOOS values reflected moderate to severe problems.

Registry Data Highlight Increased Revision Rates for Endobutton/Biosure HA in ACL Reconstruction With Hamstring Tendon Autograft

Background: Compared with a patellar tendon autograft (PT), a hamstring tendon autograft (HT) has an increased risk of revision after anterior cruciate ligament reconstruction (ACLR). There are no studies analyzing whether this can be explained by inferior fixation devices used in HT reconstruction or whether the revision risk of ACLR with an HT or a PT is influenced by the graft fixation. Purpose: To compare the risk of revision and the revision rates between the most commonly used combinations of fixation for HTs with PTs. Study Design: Cohort study; Level of evidence, 2. Methods: This study included all patients registered in the Norwegian Knee Ligament Registry from 2004 through 2013 who underwent primary PT or HT ACLR with no concomitant ligament injury and known graft fixation. The 2-year revision rates were calculated using the Kaplan-Meier analysis. Hazard ratios (HRs) for revision at 2 years were calculated using multivariate Cox regression models. Results: A total of 14,034 patients with primary ACLR were identified: 3806 patients with PTs and 10,228 patients with HTs; the mean follow-up time was 4.5 years. In the HT group, 5 different combinations of fixation in the femur/tibia were used in more than 500 patients: Endobutton/RCI screw (n = 2339), EZLoc/WasherLoc (n = 1352), Endobutton/Biosure HA (n = 1209), Endobutton/Intrafix (n = 687), and TransFix II/metal interference screw (MIS) (n = 620). The crude 2-year revision rate for patients with PTs was 0.7% (95% CI, 0.4%-1.0%), and for patients with HTs, it ranged between the groups from 1.5% (95% CI, 0.5%-2.4%) for TransFix II/MIS to 5.5% (95% CI, 4.0%-7.0%) for Endobutton/Biosure HA. When adjusted for detected confounding factors and compared with patients with PTs, the HR for revision at 2 years was increased for all HT combinations used in more than 500 patients, and the combinations Endobutton/Biosure HA and Endobutton/Intrafix had the highest HRs of 7.3 (95% CI, 4.4-12.1) and 5.5 (95% CI, 3.1-9.9), respectively. Conclusion: The choice of fixation after ACLR with an HT has a significant effect on a patient’s risk of revision. In this study population, none of the examined combinations of HT fixation had a revision rate as low as that for a PT.

Outcomes After Anterior Cruciate Ligament Reconstruction Using the Norwegian Knee Ligament Registry of 4691 Patients

Background: While the effects of concurrent meniscal resection and anterior cruciate ligament reconstruction (ACLR) are known to decrease patient outcomes and increase the rate of osteoarthritis over the long term, overall short-term patient functional outcomes in a large cohort of patients are not well known. Purpose/Hypothesis: The purpose of this study was to compare the preoperative and 2-year postoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale scores after ACLR with and without meniscal injury. The hypothesis was that, in comparison with an isolated ACLR, patients with a medial meniscal (MM) or lateral meniscal (LM) resection with an ACLR would have significantly decreased 2-year postoperative KOOS outcomes, while those with an ACLR with an MM or LM repair would be indistinguishable from isolated ACLR. Study Design: Cohort study; Level of evidence, 2. Methods: The Norwegian Knee Ligament Registry (NKLR) was used to evaluate outcomes for a total of 4691 patients with primary ACLR. The KOOS scoring system was used to evaluate patients on 5 subscales (Pain, Other Symptoms, Activities of Daily Life [ADL], Sport and Recreation Function, and Quality of Life [QoL]) at time of surgery and at 2-year postoperative follow-up. Patients with isolated ACLR and ACLR with LM repair, LM resection, MM repair, or MM resection were compared using multiple linear regression modeling. Results: Preoperatively, in comparison with isolated ACLR, patients who had an ACLR with either an MM repair or MM resection had significantly lower scores for all KOOS subscores, and LM repair had significantly decreased scores on the Other Symptoms, Pain, and ADL subscales. Postoperatively, in comparison with isolated ACLR, 2-year KOOS outcomes were not significantly different between patients with ACLR and LM repair, MM resection, or LM resection; however, those with MM repair had significantly lower scores on the Other Symptoms and QoL subscales. Conclusion: Patients with ACLR with meniscal resections do not exhibit decreased clinical outcomes at 2 years postoperatively. It is recommended that clinicians follow patients with ACLR and concurrent meniscal treatment for longer than 2 years postoperatively.

Associations between inadequate knee function detected by KOOS and prospective graft failure in an anterior cruciate ligament-reconstructed knee

First, to evaluate whether the 2year post-operative Knee injury and Osteoarthritis Outcome Score (KOOS) in primary anterior cruciate ligament reconstructions (ACLRs) was significantly different between patients that did not go on to have a subsequent revision after the 2year post-operative control and the ones that did. Second, to test whether the "clinically failure" value of KOOS quality of life (QoL)<44 was indicative of a clinically relevant difference in the risk of subsequent revision ACLR. ACLRs reported to the Norwegian Knee Ligament Registry between June 2004 and December 2009. 5,517 primary ACLRs with at least 2-year follow-up with KOOS QoL before revision surgery. There were clinically significant differences, adjusted and unadjusted, in both the KOOS Sport and Recreation and QoL subscales in patients with a later revision surgery compared to those that did not have a revision surgery. In adjusted models, the risk of later ACLR revision was 3.7 (95% CI 2.2-6.0) higher in patients with a 2-year KOOS QoL<44 compared to patients with a KOOS QoL≥44. For every 10-point reduction in the KOOS QoL, a 33.6% (95% CI 21.2-47.5%) higher risk for later ACLR revision was observed. This study reveals an association between inadequate knee function, as measured by KOOS, and a prospective ACL-reconstructed graft failure. Prognostic study (prospective cohort study), Level II.

Increased Risk of Revision With Hamstring Tendon Grafts Compared With Patellar Tendon Grafts After Anterior Cruciate Ligament Reconstruction

Background: The graft choice for anterior cruciate ligament reconstruction (ACLR) is controversial. Hamstring tendon (HT) autografts and patellar tendon (PT) autografts are the most common grafts used and have shown similar subjective and objective outcomes. Purpose: To compare the revision rate between HT and PT autografts used in ACLR in Norway and to estimate the influence of patient age and sex. Study Design: Cohort study; Level of evidence, 2. Methods: The study included all patients who underwent primary ACLR without concomitant ligament injuries registered in the Norwegian Knee Ligament Registry from 2004 through 2012. The cohort was stratified by age group (15-19, 20-29, and ≥30 years) and autograft type (HT or PT). Revision rates at 1, 2, and 5 years were calculated using the Kaplan-Meier analysis, and hazard ratios (HRs) for revision were calculated using multivariate Cox regression models. Results: With a mean follow-up of 4.0 years, 12,643 primary ACLRs were identified, with 3428 PT and 9215 HT grafts, among which 69 revisions with PT grafts and 362 revisions with HT grafts were performed. The overall 5-year revision rate was 4.2%. A higher revision rate was recorded for HT versus PT grafts at all follow-up times. When adjusted for sex, age, and type of graft, the HR for revision was 2.3 (95% CI, 1.8-3.0) for HT grafts compared with PT grafts. The HR for revision in the youngest age group was 4.0 (95% CI, 3.1-5.2) compared with the oldest age group. Sex had no effect on the revision rate. Conclusion: Patients with HT grafts had twice the risk of revision compared with patients with PT grafts. Younger age was the most important risk factor for revision, and no effect was seen for sex. Further studies should be conducted to identify the cause of the increased revision rate found for HT grafts.

Posterior cruciate ligament, exploring the unknown

The posterior cruciate ligament (PCL) is the strongest ligament of the knee, but it is rarely reconstructed in isolation. Although generally accepted that multi-ligamentous knee injuries involving PCL requires operative intervention, the treatment of PCL injuries in isolation is less clearcut and a point of controversy. The need for operative treatment of isolated PCL injuries has been reported to be as low as 3 % [6]. Several reasons can be put forward as to why this is in common practice; however, it is well known that some patients with this injury have significantly reduced knee function and improved knee stability after surgery [1]. On the other side, there are plenty of examples on top athletes, who have sustained PCL injuries, who have been able to return to their sports without surgical intervention [7]. The line between surgical and non-surgical approach is blurred and represents a definite challenge for the knee surgeon to provide the best advice to the individual patient. The lack of consensus on the treatment of PCL injuries would suggest that international collaboration is needed in order to make progress in this field of knee surgery. The ESSKA organization U45 committee has committed to focus on this area over the last 2 years. The U45 members agreed that anatomy, symptoms, evaluation, surgery and rehabilitation were the most pertinent issues to explore. During the ESSKA Congress in May 2012, a symposium and ICL were dedicated to discuss and highlight these matters. The U45 committee decided early in their work to publish a special issue in KSST journal to focus on subjects related to the PCL. The results from this work are found in this issue of the journal, and the committee has been fortunate to have gained from the extensive experience of Professor Robert LaPrade and his group, who have produced two very detailed review papers outlining the current evidence-based guidelines for the use of PCL braces and rehabilitation in this difficult knee injury [4, 5]. The current issue also contains two very informative papers on the surgical anatomy: the first, by Van Hoof et al. [8], describes a novel technique using 3D CT to delineate the PCL, while the second, by Hatsushika et al. [3] provides an accurate description of the individual fibres, which comprise each bundle of the PCL. As always in surgery, understanding the anatomy is the key to success, and given the published results on PCL surgery, a review of the surgical anatomy represents one of the most important key stones in continuing to make progress in this area. As surgeons, we always have to be aware of the variation in anatomy and function. Over the past 10 years, great strides have been made in furthering our understanding in the anatomy and biomechanics of the anterior cruciate ligament (ACL) and posterolateral corner, in addition to the development of better and more effective reconstruction techniques. We can be heartened that further advancements can also be made in PCL surgery. Registry data from the Norwegian Knee Ligament Registry, published in this issue of the journal, demonstrate that patients with isolated PCL injuries are significantly more disabled than those with ACL injuries; however, it takes a median of 21 months from the index injury before the decision to intervene operatively and perform a reconstruction is made [2]. A. Aroen (&) Oslo Sports Trauma Research Center and Department of Orthopedic Surgery, Akershus University Hospital, University of Oslo, 1478 Lorenskog, Norway e-mail: asben@online.no; asbjorn.aroen@medisin.uio.no