Lars-Petter Granan

The Scandinavian ACL registries 2004–2007: baseline epidemiology

Background and purpose No prospective surveillance systems have been available for monitoring the outcome of cruciate ligament surgery in Scandinavia (Denmark, Norway, and Sweden). In the present paper we describe the Scandinavian ACL registries including their main function, similarities, and preliminary baseline results. Methods The Scandinavian registries were established in 2004 (Norway) and 2005 (Denmark and Sweden). The Danish and Swedish registries were originally based on the Norwegian registry, and there is no overriding difference between the three. In Denmark, all hospitals and clinics are legally bound to report to an approved national database. In Norway and Sweden, the registries are based on voluntarily reporting by surgeons. Results The annual incidence of primary ACL reconstructions is higher in Denmark than in Norway, except in females younger than 20 years. Among Scandinavian surgeons, there is a similar approach to the patients. Differences do, however, exist regarding choice of grafts, choice of implants, and choice of treatment of simultaneous meniscal and cartilage injuries; the proportion of ACL reconstructions performed as outpatient surgery; and the use of prophylactic anticoagulation. Clinically, the preoperative KOOS scores are not significantly different between the Scandinavian registries, except that Denmark reports more symptoms both pre- and postoperatively. Interpretation The Scandinavian national ACL registries will generate new data about ACL reconstructions. They will contribute important knowledge regarding ACL epidemiology. They will be the only source of data on the performance of a wide range of different implants and techniques. In addition, they will hopefully have an impact on the selection of methods for ACL reconstructions in Scandinavia and elsewhere.

Development of a National Cruciate Ligament Surgery Registry The Norwegian National Knee Ligament Registry

Background No prospective surveillance system exists for monitoring the outcome of cruciate ligament surgery. Purpose This article is intended to describe the development and procedures of the Norwegian National Knee Ligament Registry (NKLR), including baseline results from the first 2 years of operation. Study Design Cohort study (prevalence); Level of evidence, 1. Methods The NKLR was established on June 7, 2004 to collect information prospectively on all cases of cruciate ligament reconstruction surgery in Norway. Information on the details of surgery is gathered through a registration form completed by the surgeon postoperatively, and a validated knee outcome score form is completed by the patients preoperatively and at follow-ups on all patients at 2, 5, and 10 years postoperatively. Hospital compliance was examined in 2005 and 2006. Results A total of 2793 primary cruciate ligament reconstruction surgeries were registered by 57 hospitals. This corresponds to an annual population incidence of primary anterior cruciate ligament reconstruction surgeries of 34 per 100 000 citizens (85 per 100 000 citizens in the main at-risk age group of 16–39 years). After 21 months of operation, the NKLR had an overall compliance of 97% when compared with the hospital records. Conclusions A national population-based cruciate ligament registry has been developed, implemented, and maintained in Norway. The registry will each year enroll approximately 1500 primary cruciate ligament reconstruction cases. It is expected that inadequate procedures and devices can be identified, as well as prognostic factors associated with good and poor outcomes, at least for the most frequent categories.

Timing of Anterior Cruciate Ligament Reconstructive Surgery and Risk of Cartilage Lesions and Meniscal Tears: A Cohort Study Based on the Norwegian National Knee Ligament Registry

Background There is inadequate evidence to determine when to perform surgery on anterior cruciate ligament—deficient knees. Purpose To study the association between timing of anterior cruciate ligament reconstruction and the risk of having meniscal tears and cartilage lesions. Study Design Cohort study (prognosis); Level of evidence, 2. Methods All patients registered in the Norwegian National Knee Ligament Registry who had undergone primary anterior cruciate ligament reconstruction from 2004 and throughout 2006 were reviewed. Logistic regression analyses were used to estimate the relationship between time from injury until anterior cruciate ligament surgery and the risk of meniscal tears or cartilage lesions. Results Of a total of 3475 patients, there were 909 patients (26%) with cartilage lesions, 1638 patients (47%) with meniscal tears, and 527 patients (15%) with both cartilage and meniscal lesions. The odds of a cartilage lesion in the adult knee (>16 years) increased by 1.006 (95% confidence interval, 1.003-1.010) for each month that elapsed from injury to surgery. The cartilage in young adults (17-40 years) deteriorated further with an increase in odds of 1.03 (95% confidence interval, 1.02-1.05) related to the aging in years of the patient. The odds for meniscal tears in young adults increased by 1.004 (95% confidence interval, 1.002-1.006) for each month that elapsed since injury. The presence of 1 degenerative lesion increased the odds of having the other degenerative lesion by between 1.6 and 2.0 in all patient groups. Conclusion The odds of a cartilage lesion in the adult knee increased by nearly 1% for each month that elapsed from the injury date until the surgery date and that of cartilage lesions were nearly twice as frequent if there was a meniscal tear, and vice versa.

Comparison of Community-Based ACL Reconstruction Registries in the U.S. and Norway

INTRODUCTION Joint registries have demonstrated value as a resource for the study of large numbers of patients, providing the opportunity to study rare occurrences and identify early failures of surgical procedures. Anterior cruciate ligament (ACL) reconstruction registries have been established in Norway and the U.S. In this study, we compared the preoperative characteristics of the Norwegian National Knee Ligament Registry (NKLR) and the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry (KP ACLRR) cohorts. METHODS A cross-sectional comparison of the NKLR and KP ACLRR cohorts registered between 2005 and 2010 was performed. Aggregate level data including preoperative patient characteristics, mechanisms of injury, preoperative Knee Injury and Osteoarthritis Outcome Score (KOOS), intraoperative findings, and adjusted revision rates were shared between the two registries, and a descriptive analysis was conducted. RESULTS During the study period, 10,468 primary ACL reconstructions were entered in the NKLR and 10,394, in the KP ACLRR. The age at the time of surgery was similar between the two cohorts (twenty-seven years in the NKLR versus twenty-eight years in the KP ACLRR), although the KP ACLRR had a higher proportion of males (65% versus 58%, p < 0.001). The revision rate per follow-up year was 0.9% in the NKLR and 1.5% in the KP ACLRR. Soccer was the most common mechanism of injury in both registries (40.0% in the NKLR and 26.6% in the KP ACLRR). The preoperative KOOS was statistically different, but the difference was not clinically relevant (defined as a change of >10 points). A higher prevalence of meniscal tears was seen in the KP ACLRR (61% versus 49%, p < 0.001). CONCLUSIONS Baseline findings are so congruent between the NKLR and the KP ACLRR cohorts that comparisons between these two registries will likely provide information to the orthopaedic community that can be generalized.

How does a combined preoperative and postoperative rehabilitation programme influence the outcome of ACL reconstruction 2 years after surgery? A comparison between patients in the Delaware-Oslo ACL Cohort and the Norwegian National Knee Ligament Registry

Background Preoperative knee function is associated with successful postoperative outcome after anterior cruciate ligament reconstruction (ACLR). However, there are few longer term studies of patients who underwent progressive preoperative and postoperative rehabilitation compared to usual care. Objectives To compare preoperative and 2 year postoperative patient-reported outcomes (PROs) in patients undergoing progressive preoperative and postoperative rehabilitation at a sports medicine clinic compared with usual care. Methods We included patients aged 16–40 years undergoing primary unilateral ACLR. The preoperative and 2 year postoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) of 84 patients undergoing progressive preoperative and postoperative rehabilitation at a sports medicine clinic (Norwegian Research Center for Active Rehabilitation (NAR) cohort) were compared with the scores of 2690 patients from the Norwegian National Knee Ligament Registry (NKLR). The analyses were adjusted for sex, age, months from injury to surgery and cartilage/meniscus injury at ACLR. Results The NAR cohort had significantly better preoperative KOOS in all subscales, with clinically relevant differences (>10 points) observed in KOOS Pain, activities of daily living (ADL), Sports and Quality of Life. At 2 years, the NAR cohort still had significantly better KOOS with clinically relevant differences in KOOS Symptoms, Sports and Quality of Life. At 2 years, 85.7–94% of the patients in the NAR cohort scored within the normative range of the different KOOS subscales, compared to 51.4–75.8% of the patients in the NKLR. Conclusions Patients in a prospective cohort who underwent progressive preoperative and postoperative rehabilitation at a sports medicine clinic showed superior patient-reported outcomes both preoperatively and 2 years postoperatively compared to patients in the NKLR who received usual care.

Intraoperative findings and procedures in culturally and geographically different patient and surgeon populations: An anterior cruciate ligament reconstruction registry comparison between Norway and the USA

Background and purpose Patient and implant registries are important clinical tools in monitoring and benchmarking quality of care. For comparisons amongst registries to be valid, a common data set with comparable definitions is necessary. In this study we compared the patients in the Norwegian Knee Ligament Registry (NKLR) and the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry (KP ACLRR) with regard to intraarticular findings, procedures, and graft fixation characteristics reported by the operating surgeon for both primary and revision anterior cruciate ligament reconstructions (ACLRs). Methods We performed a cross-sectional comparison of the NKLR and KP ACLRR cohorts registered between 2005 and 2010. Aggregate-level data including patient characteristics (age, sex, and laterality), meniscal and cartilage injury patterns and corresponding treatment procedures, choice of graft, and fixation characteristics (type and component material) were shared between registries. Descriptive analyses were then conducted. Results During the study period, 11,217 ACLRs were registered in the NKLR and 11,050 were registered in the KP ACLRR. In the NKLR, hamstring autograft was used more (68% vs. 30%) for primary ACLRs and allograft was used less (0.2% vs. 41%) than in the KP ACLRR. The KP ACLRR reports more meniscal tears among both primary and revision ACLRs (63% and 50% vs. 49% and 36%). The NKLR reports less use of biodegradable fixation devices. Conclusions Baseline findings between the NKLR and the KP ACLRR were congruent regarding patient characteristics and most injury patterns, adding to the evidence that comparisons and collaborations between these registries will provide generalizable information to the international orthopedic community. The variation in the treatment, including graft and implant selection and meniscus procedures, between the 2 registries provides opportunities to explore the impact of treatment choices on the outcomes of ACLRs.

Sport-Specific Injury Pattern Recorded During Anterior Cruciate Ligament Reconstruction

Background: Anterior cruciate ligament (ACL) injuries are more commonly seen with certain cutting and pivoting sports. However, injury patterns associated with these sports have not been well described. Purpose: (1) To describe the patient demographics and injury pattern at the time of ACL reconstruction (ACLR) by activities that lead to ACL injuries and (2) to estimate the association of activities at the time of injury with the odds of isolated ACL injuries as well as with meniscus, cartilage, and multiligament injuries diagnosed at the time of ACLR. Study Design: Cross-sectional study; Level of evidence, 3. Methods: This study combined 2 ACLR registry cohorts, from Norway and the United States, from 2004 to 2011. A cohort of 10,958 primary ACLRs was included. The most prevalent sports activities at the time of injury were the following: soccer, skiing, American football, basketball, and team handball. The end points were the concurrent injury patterns at the time of ACLR: isolated ACL, meniscus, cartilage, and multiligament injuries. Results: All sports were compared with the most prevalent injury mechanism: soccer. Skiing injuries were 1.13 (95% confidence interval [CI], 1.01-1.27) times more likely to result in isolated ACL tears, 2.05 (95% CI, 1.01-4.16) times more likely to result in posterior cruciate ligament tears, 1.94 (95% CI, 1.51-2.49) times more likely to result in medial collateral ligament (MCL) tears, and 1.73 (95% CI, 1.38-2.17) times more likely to result in multiligament injuries. Athletes playing American football were 2.72 (95% CI, 1.32-5.62) times more likely to have MCL tears. Those injured playing basketball were 1.28 (95% CI, 1.06-1.54) times more likely to have lateral meniscus tears, 1.23 (95% CI, 1.01-1.51) times more likely to have cartilage damage, and 1.38 (95% CI, 1.11-1.72) times more likely to have meniscus and cartilage injuries. Athletes injured playing team handball were less likely to have MCL tears (odds ratio [OR], 0.68; 95% CI, 0.46-0.99) and more likely to have lateral meniscus injuries (OR, 1.27; 95% CI, 1.10-1.48). Conclusion: Injury patterns were associated with certain sports. Compared with soccer, American football has a higher likelihood of resulting in multiligament injuries, whereas basketball has a higher likelihood of resulting in cartilage and lateral meniscus injuries. Injury patterns seen at the time of surgery may reflect the forces applied to the knee by the specific sports performed.

Patient and Surgeon Characteristics Associated With Primary Anterior Cruciate Ligament Reconstruction Graft Selection

Background: It has been suggested that a surgeon’s experience and training are the most important factors associated with graft selection, but no studies have qualified this association. Graft usage prevalence has not been described for large anterior cruciate ligament reconstruction (ACLR) populations in the United States. Purpose: To describe the prevalence of graft usage in a large community-based practice and evaluate the association of patient, surgeon, and site characteristics with choice of primary ACLR graft. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Primary ACLRs performed between February 2005 and June 2010 were selected for the study. A community-based ligament registry was used to identify cases and variables used for analysis. Graft choice (any allograft, hamstring autograft, and bone–patellar tendon–bone [BPTB] autograft) was compared by patient characteristics and surgeon and site characteristics. Associations between independent variables and graft choice were evaluated using a polychotomous regression model. Results: Of the 9849 patients included in the study, 64% were male, and overall median age was 28 years. Of these, 2796 (28.4%) received BPTB autografts, 3013 (30.6%) received hamstring autografts, and 4040 (41.0%) received allografts. The prevalence of graft source by patients’ gender, race, age, body mass index (BMI), as well as surgeons’ fellowship training status, average volume, and site volume were significantly different (all P < .001). Adjusted models showed that patients’ gender (P < .001), race (P = .018), age (P < .001), BMI (P < .001), as well as surgeons’ fellowship training status (P < .001), average volume (P < .001), and site volume (P < .001) are associated with graft selection. Older and female patients with lower BMI were more likely to receive allografts and hamstring autografts than BPTB autografts. Cases performed by non–fellowship-trained surgeons, lower volume sites, and/or lower volume surgeons were also more likely to be performed with allografts or hamstring autografts than BPTB autografts. Conclusion: Gender, age, race, as well as facility and surgeon characteristics such as volume and location are associated with ACL graft choices.

Proportion of Patients Reporting Acceptable Symptoms or Treatment Failure and Their Associated KOOS Values at 6 to 24 Months After Anterior Cruciate Ligament Reconstruction: A Study From the Norwegian Knee Ligament Registry

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.

Registration rate in the Norwegian Cruciate Ligament Register: Large-volume hospitals perform better

Background and purpose The Norwegian Cruciate Ligament Register (NCLR) was founded in 2004. The purpose of the NCLR is to provide representative and reliable data for future research. In this study we evaluated the development of the registration rate in the NCLR. Methods The Norwegian Patient Register (NPR) and the electronic patient charts (EPCs) were used as reference data for public and private hospitals, respectively. Data were retrieved for all primary and revision anterior cruciate ligament (ACL) surgery during 2008–2009 in public hospitals and during 2008 in private hospitals. The NOMESCO classification of surgical procedures was used for identification of ACL surgeries. Public hospitals were divided into subgroups according to the annual number of operations in the NPR: small hospitals (< 30 operations) and large hospitals (≥ 30 operations). Results For the 2-year data extracted from public hospitals, 2,781 and 2,393 operations met the inclusion criteria according to the NPR and the NCLR, respectively, giving an average registration rate of 86% (95% CI: 0.85–0.87). The registration rate for small public hospitals was 69% (CI: 0.65–0.73), which was significantly less than for large public hospitals (89%, CI: 0.88–0.90; p < 0.001). In 2008, private hospitals reported 548 operations to the NCLR while 637 were found in the EPCs, giving a registration rate of 86% (CI: 0.83–0.89). In that year, the registration rate for public hospitals was 86%, which was similar to that for private hospitals. Interpretation The NCLR registration rate for the period 2008–09 was similar in both 2008 and 2009, and is satisfactory for research. There is room for improvement of registration rates, particularly in hospitals with a small volume of ACL operations.