Kristian Samuelsson

The Swedish National Anterior Cruciate Ligament Register A Report on Baseline Variables and Outcomes of Surgery for Almost 18,000 Patients

Background: The Swedish National Anterior Cruciate Ligament Register provides an opportunity for quality surveillance and research. Purpose: The primary objective was to recognize factors associated with a poorer outcome at an early stage. Study Design: Case series; Level of evidence, 4. Methods: Registrations are made using a web-based protocol with 2 parts: a patient-based section with self-reported outcome scores and a surgeon-based section, where factors such as cause of injury, previous surgery, time between injury and reconstruction, graft selection, fixation technique, and concomitant injuries are reported. The self-reported outcome scores are registered preoperatively and at 1, 2, and 5 years. Results: Approximately 90% of all anterior cruciate ligament (ACL) reconstructions performed annually in Sweden are reported in the register. Registrations during the period 2005-2010 were included (n = 17,794). After excluding multiligament reconstructions and reoperations, the male:female ratio was 57.5:42.5 for both primary (n = 15,387) and revision (n = 964) surgery. The cause of injury was soccer in approximately half the male patients and in one third of the female patients. All subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS) were significantly improved 1, 2, and 5 years postoperatively in patients undergoing primary reconstructions. In terms of the KOOS, revisions did significantly less well than primary reconstructions on all follow-up occasions, and smokers fared significantly less well than nonsmokers both preoperatively and at 2 years. Patients who had concomitant meniscal or chondral injuries at reconstruction did significantly less well preoperatively and at 1 year in terms of most KOOS subscales compared with patients with no such injuries. At 5 years, a significant difference was only found in terms of the sport/recreation subscale. Double-bundle reconstructions revealed no significant differences in terms of all the KOOS subscales at 2 years compared with single-bundle reconstructions (114 double-bundle vs 5109 single-bundle). During a 5-year period, 9.1% (contralateral, 5.0%; revision, 4.1%) of the patients underwent a contralateral ACL reconstruction or revision reconstruction of the index knee. The corresponding figure for 15- to 18-year-old female soccer players was 22.0%. Conclusion: Primary ACL reconstruction significantly improves all the subscales of the KOOS. Young female soccer players run a major risk of reinjuring their ACL or injuring the contralateral ACL; revision ACL reconstructions do less well than primary reconstructions, and smokers do less well than nonsmokers.

Anatomic Single- and Double-Bundle Anterior Cruciate Ligament Reconstruction, Part 2 Clinical Application of Surgical Technique

The anterior cruciate ligament has been and is of great interest to scientists and orthopaedic surgeons worldwide. Anterior cruciate ligament reconstruction was initially performed using an open approach. When the approach changed from open to arthroscopic reconstruction, a 2- and, later, 1-incision technique was applied. With time, researchers found that traditional arthroscopic single-bundle reconstruction did not fully restore rotational stability of the knee joint and a more anatomic approach to reconstruct the anterior cruciate ligament has been proposed. Anatomic anterior cruciate ligament reconstruction intends to replicate normal anatomy, restore normal kinematics, and protect long-term knee health. Although double-bundle anterior cruciate ligament reconstruction has been shown to result in better rotational stability in both biomechanical and clinical studies, it is vital to differentiate between anatomic and double-bundle anterior cruciate ligament reconstruction. The latter is merely a step closer to reproducing the native anatomy of the anterior cruciate ligament; however, it can still be done nonanatomically. To evaluate the potential benefits of reconstructing the anterior cruciate ligament in an anatomic fashion, accurate, precise, and reliable outcome measures are needed. These include, for example, T2 magnetic resonance imaging mapping of cartilage and quantification of graft healing on magnetic resonance imaging. Furthermore, there is a need for a consensus on which patient-reported outcome measures should be used to facilitate homogeneous reporting of outcomes.

Patient Predictors of Early Revision Surgery After Anterior Cruciate Ligament Reconstruction A Cohort Study of 16,930 Patients With 2-Year Follow-up

Background: Revision surgery is one of the most important endpoints during follow-up after anterior cruciate ligament (ACL) reconstruction. Purpose: To investigate if commonly known patient factors can predict revision surgery after ACL reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: This prospective cohort study was based on data from the Swedish National Knee Ligament Register during the period of January 1, 2005, through December 31, 2013. Patients who underwent primary ACL reconstruction with hamstring tendon or bone–patellar tendon–bone autografts were included. Follow-up started on the date of primary ACL reconstruction, and follow-up ended with ACL revision surgery, after 24 months of follow-up, or on December 31, 2013, whichever occurred first. The analyzed patient variables were activity at the time of injury, sex, age, height, weight, body mass index, smoking, and the use of smokeless tobacco. The primary study endpoint was revision surgery, defined as replacement of a primary ACL reconstruction. Relative risk (RR) and 95% CIs were calculated and adjusted for confounding factors using multivariate statistics. Results: A total of 16,930 patients were included (males, n = 9767 [57.7%]; females, n = 7163 [42.3%]). The 2-year revision rate was 1.82% (95% CI, 1.62%-2.02%). There was no significant difference between male and female revision rates (1.74% [95% CI, 1.48%-2.00%] vs 1.93% [95% CI, 1.61%-2.25%], P = .383). In both males and females there was a significantly increased risk of revision surgery associated with soccer playing and adolescence (age 13-19 years) (males: RR = 1.58 [95% CI, 1.12-2.23], P = .009 and RR = 2.67 [95% CI, 1.91-3.73], P < .001, respectively; females: RR = 1.43 [1.01-2.04], P = .045 and RR = 2.25 [95% CI, 1.57-3.24], P < .001, respectively). A combination of these predictors were associated with a further increased risk of revision surgery (males: RR = 2.87 [95% CI, 1.79-4.60], P < .001; females: RR = 2.59 [95% CI, 1.69-3.96], P < .001). Conclusion: Soccer players and adolescents had an increased risk of revision surgery after ACL reconstruction, with a respective factor of 1.5 and 2.5. Individuals with a combination of these 2 predictors carried an almost 3-fold higher risk of revision surgery. There were no significant associations for sex, height, weight, body mass index, or tobacco use.

Prevention of anterior cruciate ligament injuries in sports—Part I: Systematic review of risk factors in male athletes

AbstractPurpose The purpose of this study was to report a comprehensive literature review on the risk factors for anterior cruciate ligament (ACL) injuries in male athletes.Methods All abstracts were read and articles of potential interest were reviewed in detail to determine on inclusion status for systematic review. Information regarding risk factors for ACL injuries in male athletes was extracted from all included studies in systematic fashion and classified as environmental, anatomical, hormonal, neuromuscular, or biomechanical. Data extraction involved general characteristics of the included studies (type of study, characteristics of the sample, type of sport), methodological aspects (for quality assessment), and the principal results for each type of risk factor.ResultsThe principal findings of this systematic review related to the risk factors for ACL injury in male athletes are: (1) most of the evidence is related to environmental and anatomical risk factors; (2) dry weather conditions may increase the risk of non-contact ACL injuries in male athletes; (3) artificial turf may increase the risk of non-contact ACL injuries in male athletes; (4) higher posterior tibial slope of the lateral tibial plateau may increase the risk of non-contact ACL injuries in male athletes.ConclusionAnterior cruciate ligament injury in male athletes likely has a multi-factorial aetiology. There is a lack of evidence regarding neuromuscular and biomechanical risk factors for ACL injury in male athletes. Future research in male populations is warranted to provide adequate prevention strategies aimed to decrease the risk of this serious injury in these populations.Level of evidenceSystematic review on level I–IV studies, Level IV.

Surgical Predictors of Early Revision Surgery After Anterior Cruciate Ligament Reconstruction Results From the Swedish National Knee Ligament Register on 13,102 Patients

Background: An important objective of anterior cruciate ligament (ACL) registries is to detect and report early graft failure and revision surgery after ACL reconstruction. Purpose: To investigate surgical variables and identify predictors of revision surgery after ACL reconstruction. Study Design: Prospective cohort study; Level of evidence, 2. Methods: This prospective cohort study was based on data from the Swedish National Knee Ligament Register during the years 2005 through 2011. Eight surgical variables were investigated: graft selection, graft width, single-bundle or double-bundle techniques, femoral graft fixation, tibial graft fixation, injury-to-surgery interval, injuries to menisci, and injuries to cartilage. The primary endpoint was the 2-year incidence of revision surgery. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated and adjusted for confounders by use of multivariate statistics. Results: A total of 13,102 patients were included (5541 women [42%] and 7561 men [58%]; P < .001). Hamstring tendon autografts accounted for 90% (11,764 patients) of all reconstructions, of which 96% were performed with a single-bundle technique (11,339 patients). Patellar tendon autografts accounted for the remaining 10% (1338 patients). At index reconstruction, observed injuries to menisci and cartilage were common (40% and 28%, respectively). The overall 2-year incidence of revision surgery was 1.60% (women, 1.57%; men, 1.63%; P = .854). Patients with metal interference screw fixation of a semitendinosus tendon autograft on the tibia had a significantly reduced risk of early revision surgery (RR = 0.32; 95% CI, 0.12-0.90; P = .031). Conclusion: Metal interference screw fixation of a semitendinosus tendon autograft on the tibia was an independent predictor of significantly lower 2-year incidence of revision surgery. Graft selection, graft width, a single-bundle or a double-bundle technique, femoral graft fixation, the injury-to-surgery interval, and meniscus injury were not predictors of early revision surgery.

The Influence of Meniscal and Anterolateral Capsular Injury on Knee Laxity in Patients with Anterior Cruciate Ligament Injuries

Background: The role of the anterolateral capsule (ALC) as a secondary restraint to quantitative rotatory laxity of patients with an anterior cruciate ligament (ACL) injury is currently debated. Purpose/Hypothesis: The purpose was to determine the influence of concomitant ALC injuries as well as injuries to other soft tissue structures on rotatory knee laxity in patients with an ACL injury. It was hypothesized that a concomitant ALC injury would be associated with increased rotatory knee laxity as measured during a quantitative pivot-shift test. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Forty-one patients with an ACL injury (average age, 23 ± 6.9 years) were enrolled. Two blinded musculoskeletal radiologists reviewed magnetic resonance imaging (MRI) scans for the presence of ACL injuries and concomitant soft tissue injuries including the ALC, medial collateral ligament, lateral collateral ligament, posterolateral corner, medial meniscus, and lateral meniscus. A standardized pivot-shift test was performed under anesthesia, and rotatory laxity was quantified according to anterior translation of the lateral tibial compartment during the pivot-shift maneuver. The Student t test was used to analyze the data. Statistical significance was set at P < .05. Results: A complete ACL rupture was confirmed in all of the patients. MRI evidence of an ALC injury was observed in 21 (51%) of the patients. Patients with MRI evidence of an ALC injury had significantly higher rotatory knee laxity (3.6 ± 1.5 mm) compared with those without an ALC injury (2.7 ± 1.5 mm; P = .04). Lateral and medial meniscus injuries were detected in 17 (41%) and 19 (46%) patients, respectively. Patients with MRI evidence of either a medial meniscus injury or lateral meniscus injury had significantly higher rotatory knee laxity compared with patients without these injuries (medial meniscus: 3.7 ± 1.4 mm vs 2.7 ± 1.6 mm, respectively; lateral meniscus: 3.7 ± 1.7 mm vs 2.7 ± 1.3 mm, respectively) (P = .03 for both). Conclusion: MRI evidence of a concomitant injury to the ALC, medial meniscus, or lateral meniscus is associated with increased knee rotatory laxity in patients with an ACL injury. These structures may function as important secondary stabilizers in an ACL-injured knee. Careful assessment and proper treatment of injuries to these secondary stabilizers should be considered, especially in knees with a high level of the pivot shift.

Prevention of non-contact anterior cruciate ligament injuries in sports. Part II: systematic review of the effectiveness of prevention programmes in male athletes.

PurposeTo synthesize the results of systematic literature review focused on the effectiveness of anterior cruciate ligament (ACL) injury prevention programmes in male athletes.MethodsAll abstracts and articles of potential interest identified through the systematic literature search were reviewed in detail to determine on inclusion status. Information regarding prevention programmes to reduce ACL injuries or to modify risk factors for ACL injuries in male athletes was systematically extracted and included intervention and study design, characteristics of participants, sport and level of competition, characteristics of prevention programmes, results, and conclusions. All studies were evaluated for methodological quality to assess the risk of bias.ResultsThe principal findings of this systematic review are as follows: (1) most of the studies applied prevention programmes that utilized risk factors as outcomes of interest as opposed to ACL injury incidence (5 and 2 studies, respectively); (2) the effectiveness of prevention programmes to reduce ACL injuries in male athletes is equivocal (1 in favour, 1 against) and only refers to soccer players; (3) the effectiveness of prevention programmes to modify risk factors for ACL injuries in male athletes is controversial (2 in favour, 3 against) and outcome data are limited to cutting manoeuvres.ConclusionData regarding the effectiveness of prevention programmes to reduce ACL injuries or to modify risk factors for ACL injuries in male athletes are scarce and not conclusive. Future research to better determine the most effective approaches to optimize the effectiveness of prevention programmes targeted to reduce ACL injuries in male athletes is warranted.Level of evidenceSystematic review on level I–II evidence studies, Level II.

Dynamic knee laxity measurement devices

PurposeStudies have reported that knee kinematics and rotational laxity are not restored to native levels following traditional anterior cruciate ligament (ACL) reconstruction. This has led to the development of anatomic ACL reconstruction, which aims to restore native knee kinematics and long-term knee health by replicating normal anatomy as much as possible. The purpose of this review is to give an overview of current dynamic knee laxity measurement devices with the purpose of investigating the significance of dynamic laxity measurement of the knee. Gait analysis is not included.MethodsThe subject was discussed with experts in the field in order to perform a level V review. MEDLINE was searched according to the discussions for relevant articles using multiple different search terms. All found abstracts were read and scanned for relevance to the subject. The reference lists of the relevant articles were searched for additional articles related to the subject.ResultsThere are a variety of techniques reported to measure dynamic laxity of the knee. Technical development of methods is one important part toward better understanding of knee kinematics. Validation of devices has shown to be difficult due to the lack of gold standard. Different studies use various methods to examine different components of dynamic laxity, which makes comparisons between studies challenging.ConclusionSeveral devices can be used to evaluate dynamic laxity of the knee. At the present time, the devices are continuously under development. Future implementation should include primary basic research, including validation and reliability testing, as well as part of individualized surgery and clinical follow-up.Level of evidenceDiagnostic study, Level V.

Trends in Surgeon Preferences on Anterior Cruciate Ligament Reconstructive Techniques

Many surgeons intend to replicate the native anterior cruciate ligament (ACL) as much as possible, aiming at anatomic ACL reconstruction. An outline of new surgical preferences is starting to form; orthopedic surgeons have shifted their preferences in arthroscopic technique, graft type, and fixation during the past decade. The days of simple silk suturing of the native ACL stump to the femoral periosteum are over. Today, knee surgeons performing ACL reconstruction have a wide array of technical considerations, graft choices, and fixation techniques at hand that enable them to specifically tailor each reconstruction to each patients anatomy and specific needs.

Level of Evidence in Anterior Cruciate Ligament Reconstruction Research A Systematic Review

Background: There have been numerous studies on anterior cruciate ligament (ACL) reconstruction. Considering the vast number of studies, a quick assessment reveals rather few with a high level of evidence. Purpose: The primary aim was to categorize the study type and level of evidence of studies on primary ACL reconstruction by applying the level of evidence rating system proposed by the Oxford Centre for Evidence-Based Medicine. The secondary aims were to correlate the level of evidence with the impact factor of the journal, to evaluate the level of evidence over time, and to evaluate the geographic distribution of the included studies. Study Design: Systematic review. Methods: An electronic search was performed using the databases PubMed, EMBASE, and Cochrane Library. Studies published from January 1995 to August 2011 were included. Therapeutic studies written in English that report on isolated primary ACL reconstruction with clinical outcome measurements related to the reconstruction were included. Categorization and implementation of the level of evidence were performed. Correlation between the level of evidence and the impact factor of the journal was analyzed together with linear regression models to reveal any significant trends over time. Results: A total of 7154 studies were analyzed, of which 1510 were included. Analysis of the study types revealed that case series (n = 494; 32.7%) was the most frequent study type. Randomized controlled trials represented 9.2% (n = 139) of the sample, whereas meta-analyses were rare. Single-bundle studies were the most common studies (n = 1333; 88.3%), followed by double-bundle (n = 98; 6.5%) and single- versus double-bundle (n = 79; 5.2%). The journals Arthroscopy, Knee Surgery Sports Traumatology Arthroscopy (KSSTA), and American Journal of Sports Medicine (AJSM) represented 43.5% (n = 657) of the included studies. Arthroscopy had the highest number of publications in general and in level 4 and 5 studies, whereas AJSM had the lowest number of the 3. AJSM had the highest number of level 1 and 2 studies in general. The mean level of evidence calculated without level 5 studies was 3.15 for Arthroscopy, 3.20 for KSSTA, and 2.9 for AJSM. There was a significant correlation (P < .05) between the impact factor of the journal and mean level of evidence of the journal and the proportion high level of evidence studies (levels 1 and 2). There was a significant (P < .05) trend toward higher mean level of evidence over time. Conclusion: Most therapeutic studies on primary ACL reconstruction were of low level of evidence, and there was a positive correlation between the journal’s impact factor and the mean level of evidence and the proportion of high level of evidence studies. There was significant trend toward higher mean level of evidence over time.