Systematic review: Annual incidence of ACL injury and surgery in various populations

Hamstring autograft versus soft-tissue allograft in anterior cruciate ligament reconstruction: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

To compare outcomes of anterior cruciate ligament (ACL) reconstruction with hamstring autograft versus soft-tissue allograft by systematic review and meta-analysis.

METHODS

A systematic review of randomized controlled studies comparing hamstring autograft with soft-tissue allograft in ACL reconstruction was performed. Studies were identified by strict inclusion and exclusion criteria. Descriptive statistics were reported. Where possible, the data were pooled and a meta-analysis was performed using RevMan software (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). Dichotomous data were reported as risk ratios, whereas continuous data were reported as standardized mean differences and 95% confidence intervals. Heterogeneity was assessed by use of I(2) for each meta-analysis. Study methodologic quality was analyzed with the Modified Coleman Methodology Score and Jadad scale.

RESULTS

Five studies with 504 combined patients (251 autograft and 253 allograft; 374 male and 130 female patients) with a mean age of 29.9 ± 2.2 years were included. The allografts used were fresh-frozen hamstring, irradiated hamstring, mixture of fresh-frozen and cryopreserved hamstring, fresh-frozen tibialis anterior, and fresh-frozen Achilles tendon grafts without bone blocks. The mean follow-up period was 47.4 ± 26.9 months, with a mean follow-up rate of 83.3% ± 8.6%. Two studies found a longer operative time with autograft than with allograft (77.1 ± 2.0 minutes v 59.9 ± 0.9 minutes, P = .008). Meta-analysis showed no statistically significant differences between autografts and allografts for any outcome measures (P > .05 for all tests). One study found significantly greater laxity for irradiated allograft than for autograft. The methodologic quality of the 5 studies was poor, with a mean Modified Coleman Methodology Score of 54.4 ± 6.9 and mean Jadad score of 1.6 ± 1.5.

CONCLUSIONS

On the basis of this systematic review and meta-analysis of 5 randomized controlled trials, there is no statistically significant difference in outcome between patients undergoing ACL reconstruction with hamstring autograft and those undergoing ACL reconstruction with soft-tissue allograft. These results may not extrapolate to younger patient populations. The methodology of the available randomized controlled trials comparing hamstring autograft and soft-tissue allograft is poor.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

Suspensory fixation versus novel transverse crosspin for femoral fixation in anterior cruciate ligament reconstruction

BACKGROUND AND AIM

There is still no gold standard technique for graft fixation during anterior cruciate ligament reconstruction. We compared the functional outcomes of patients receiving either ToggleLoc with ZipLoop technology or Translig transverse crosspin device for femoral graft fixation.

MATERIALS AND METHODS

A total of 118 patients were randomly allocated into two groups to receive either Translig(®) transverse crosspin (Translig group 1: n = 51, mean age 28.34 ± 7.83 years, age 18-40 years) or ToggleLoc with ZipLoop technology (ToggleLoc group: n = 67, mean age 26.85 ± 8.76, age 16-41 years) for femoral graft fixation. Early and 1-year assessment was made with Lysholm knee scale, International Knee Documentation Committee Scoring, Tegner Activity Level Scale, KT-1000 arthrometer and pivot shift test.

RESULTS

Preoperative vs. postoperative functional parameters showed significant improvement in both groups. Two groups were similar in terms of Lysholm knee scale, IKDC and Tegner activity scores (p > 0.05). The KT-1000 arthrometer revealed slightly less anterior sliding in Translig group than that in ToggleLoc group (p > 0.05). ToggleLoc technique allowed a radiographically more horizontal placement of the graft than Translig technique.

CONCLUSION

Two distinct techniques used in this study are likely to be suitable for femoral graft fixation during anterior cruciate ligament reconstruction with the femoral tunnel being created via anteromedial approach.

Are magnetic resonance imaging recovery and laxity improvement possible after anterior cruciate ligament rupture in nonoperative treatment?

PURPOSE

This study aimed to determine whether anterior cruciate ligament (ACL) features on magnetic resonance imaging (MRI) and knee laxity are improved 2 years after ACL rupture treated nonoperatively and to analyze the relation between changes in scores of ACL features and changes in laxity.

METHODS

One hundred fifty-four eligible patients were included in a prospective multicenter cohort study with 2-year follow-up. Inclusion criteria were (1) ACL rupture diagnosed by physical examination and MRI, (2) MRI within 6 months after trauma, and (3) age 18 to 45 years. Laxity tests and MRI were performed at baseline and at 2-year follow-up. Fifty of 143 patients, for whom all MRI data was available, were treated nonoperatively and were included for this study. Nine ACL features were scored using MRI: fiber continuity, signal intensity, slope of ACL with respect to the Blumensaat line, distance between the Blumensaat line and the ACL, tension, thickness, clear boundaries, assessment of original insertions, and assessment of the intercondylar notch. A total score was determined by summing scores for each feature.

RESULTS

Fiber continuity improved in 30 patients (60%), and the empty intercondylar notch resolved for 22 patients (44%). Improvement in other ACL features ranged from 4% to 28%. Sixteen patients (32%) improved on the Lachman test (change from soft to firm end points [n = 14]; decreased anterior translation [n = 2]), one patient (2%) showed improvement with the KT-1000 arthrometer (MEDmetric, San Diego, CA) and 4 patients (8%) improved on the pivot shift test. Improvement on the Lachman test was moderately negatively associated with the total score of ACL features at follow-up. Analyzing ACL features separately showed that only signal intensity improvement, clear boundaries, and intercondylar notch assessment were positively associated with improvement on the Lachman test.

CONCLUSIONS

Two years after ACL rupture and nonoperative management, patients experienced partial recovery on MRI, and some knee laxity improvement was present. Improvement of ACL features on MRI correlates moderately with improved laxity.

LEVEL OF EVIDENCE

Level II, Prospective comparative study.

Accuracy of clinical tests in the diagnosis of anterior cruciate ligament injury: a systematic review

BACKGROUND

Numerous clinical tests are used in the diagnosis of anterior cruciate ligament (ACL) injury but their accuracy is unclear. The purpose of this study is to evaluate the diagnostic accuracy of clinical tests for the diagnosis of ACL injury.

METHODS

STUDY DESIGN

Systematic review. The review protocol was registered through PROSPERO (CRD42012002069). Electronic databases (PubMed, MEDLINE, EMBASE, CINAHL) were searched up to 19th of June 2013 to identify diagnostic studies comparing the accuracy of clinical tests for ACL injury to an acceptable reference standard (arthroscopy, arthrotomy, or MRI). Risk of bias was appraised using the QUADAS-2 checklist. Index test accuracy was evaluated using a descriptive analysis of paired likelihood ratios and displayed as forest plots.

RESULTS

A total of 285 full-text articles were assessed for eligibility, from which 14 studies were included in this review. Included studies were deemed to be clinically and statistically heterogeneous, so a meta-analysis was not performed. Nine clinical tests from the history (popping sound at time of injury, giving way, effusion, pain, ability to continue activity) and four from physical examination (anterior draw test, Lachman's test, prone Lachman's test and pivot shift test) were investigated for diagnostic accuracy. Inspection of positive and negative likelihood ratios indicated that none of the individual tests provide useful diagnostic information in a clinical setting. Most studies were at risk of bias and reported imprecise estimates of diagnostic accuracy.

CONCLUSION

Despite being widely used and accepted in clinical practice, the results of individual history items or physical tests do not meaningfully change the probability of ACL injury. In contrast combinations of tests have higher diagnostic accuracy; however the most accurate combination of clinical tests remains an area for future research.

CLINICAL RELEVANCE

Clinicians should be aware of the limitations associated with the use of clinical tests for diagnosis of ACL injury.

Knee shape might predict clinical outcome after an anterior cruciate ligament rupture

We have investigated whether shape of the knee can predict the clinical outcome of patients after an anterior cruciate ligament rupture. We used statistical shape modelling to measure the shape of the knee joint of 182 prospectively followed patients on lateral and Rosenberg view radiographs of the knee after a rupture of the anterior cruciate ligament. Subsequently, we associated knee shape with the International Knee Documentation Committee subjective score at two years follow-up. The mean age of patients was 31 years (21 to 51), the majority were male (n = 121) and treated operatively (n = 135). We found two modes (shape variations) that were significantly associated with the subjective score at two years: one for the operatively treated group (p = 0.002) and one for the non-operatively treated group (p = 0.003). Operatively treated patients who had higher subjective scores had a smaller intercondylar notch and a smaller width of the intercondylar eminence. Non-operatively treated patients who scored higher on the subjective score had a more pyramidal intercondylar notch as opposed to one that was more dome-shaped. We conclude that the shape of the femoral notch and the intercondylar eminence is predictive of clinical outcome two years after a rupture of the anterior cruciate ligament.

Cite this article: Bone Joint J 2014;96-B:737–42.

The epidemiology of medial collateral ligament sprains in young athletes

BACKGROUND

A medial collateral ligament (MCL) knee sprain is a prevalent injury in athletic populations that may result in significant time lost to injury. Remarkably little is known of the epidemiology of this injury.

PURPOSE

To define the incidence of MCL tears and to determine the demographic and athletic risk factors.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

A longitudinal cohort study was performed to examine the epidemiology of isolated MCL sprains at the United States Military Academy (USMA) between 2005 and 2009. Charts and radiographic studies were reviewed by an independent orthopaedic surgeon to identify all new isolated MCL sprains resulting in time lost to sport and activity that occurred within the study period. Incidence rates (IRs) with 95% confidence intervals (CIs) were calculated per 1000 person-years at risk and by sex, sport, and level of competition. The IR per 1000 athlete-exposures (AEs) was also determined. Incidence rate ratios (IRRs) and respective 95% CIs were calculated between male and female students, intercollegiate and intramural athletes, and male and female intercollegiate athletes involved in selected sports. Chi-square and Poisson regression analyses were used to examine the relationship between the variables of interest and the incidence of MCL sprains, with statistical significance set at P < .05.

RESULTS

A total of 128 cadets sustained isolated MCL injuries during 17,606 student person-years from 2005 to 2009. This resulted in an IR of approximately 7.3 per 1000 person-years. Of the 128 injuries, 114 were in male athletes (89%) and 14 were in female athletes (11%). Male cadets had a 44% higher IR than did female cadets (7.60 vs 5.36, respectively), although this was not significant (P = .212). Of 5820 at-risk intercollegiate athletes, 59 (53 male, 6 female) sustained an isolated MCL sprain during 528,523 (407,475 male, 121,048 female) AEs for an overall IR of 10.14 per 1000 person-years and 0.11 per 1000 AEs. The IRR of MCL sprains of men compared with women involved in intercollegiate athletics was 2.87 (95% CI, 1.24-8.18) per 1000 person-years and 2.62 (95% CI, 1.13-7.47) per 1000 AEs. Of 21,805 at-risk intramural athletes, with quarterly participation, 16 (all male) sustained isolated MCL injuries during 225,683 AEs for an overall IR of 0.07 per 1000 AEs. The IRs of MCL injuries of intercollegiate and intramural athletes did not differ significantly. In intercollegiate sports, wrestling (0.57), judo (0.36), hockey (0.34), and rugby (men's, 0.22; women's, 0.23) had the highest IRs per 1000 AEs. When examining men's intercollegiate athletics, the IRRs of wrestling (13.41; 95% CI, 1.80-595.27) and hockey (8.12; 95% CI, 0.91-384.16) were significantly higher compared with that of lacrosse. Among women's intercollegiate sports as well as intramural sports, there were no significant differences in IRs. A median of 16 days was lost to injury, with 2407 total days lost for all injuries. Grade 1 MCL injuries lost a median of 13.5 days, while higher grade injuries lost a median of 29 days.

CONCLUSION

Medial collateral ligament injuries are relatively common in athletic cohorts. The most injurious sports are contact sports such as wrestling, hockey, judo, and rugby. Male athletes are at a greater risk than female athletes. Intercollegiate athletes are at a greater risk than intramural athletes. The average amount of time lost per injury was 23.2 days, with greater time lost with higher grade sprains than grade 1 sprains.

The effects of high-intensity versus low-intensity resistance training on leg extensor power and recovery of knee function after ACL-reconstruction

Objective. Persistent weakness is a common problem after anterior cruciate ligament- (ACL-) reconstruction. This study investigated the effects of high-intensity (HRT) versus low-intensity (LRT) resistance training on leg extensor power and recovery of knee function after ACL-reconstruction. Methods. 31 males and 19 females were randomized to HRT (n = 24) or LRT (n = 26) from week 8–20 after ACL-reconstruction. Leg extensor power, joint laxity, and self-reported knee function were measured before and 7, 14, and 20 weeks after surgery. Hop tests were assessed before and after 20 weeks. Results. Power in the injured leg was 90% (95% CI 86–94%) of the noninjured leg, decreasing to 64% (95% CI 60–69%) 7 weeks after surgery. During the resistance training phase there was a significant group by time interaction for power (P = 0.020). Power was regained more with HRT compared to LRT at week 14 (84% versus 73% of noninjured leg, resp.; P = 0.027) and at week 20 (98% versus 83% of noninjured leg, resp.; P = 0.006) without adverse effects on joint laxity. No other between-group differences were found. Conclusion. High-intensity resistance training during rehabilitation after ACL-reconstruction can improve muscle power without adverse effects on joint laxity.

A prospective study to assess the outcomes of revision anterior cruciate ligament reconstruction

PURPOSE

Continuously increasing numbers of primary anterior cruciate ligament (ACL) reconstructions invites a parallel increase in graft failures and need for revision ACL reconstruction surgery. High failure rates has previously stigmatised the revision surgery. We performed this study using multiple outcome measures together with clinical examination to offer a full assessment of the outcomes of this procedure.

METHODS

Twenty patients, with mean age of 29.4 years (17-50 years), were included in this study prior to their revision ACL reconstruction surgery. All patients were followed prospectively collecting the Knee injury and Osteoarthritis Outcome (KOOS), International Knee Documentation Committee (IKDC) and Tegner-Lysholm scores pre- and post-operatively together with clinical assessment of the antero-posterior knee laxity.

RESULTS

After a mean follow up interval of 30 months (16-60 months) significant post-operative improvement of IKDC, Tegner-Lysholm scores and knee antero-posterior laxity together with the Symptoms, Activities of Daily Living (ADL) and Quality of Life (QOL) components of the KOOS score was noticed (P < 0.05). However, there was no similar improvement in pain and sports components of the KOOS score (P > 0.05). There was no difference in the outcomes of different graft types.

CONCLUSION

Good outcomes of revision ACL reconstruction surgery are achievable. The use of different graft types did not affect the outcome of the procedure. Most of the patients opted to less aggressive sports participation after the revision procedure.

20 years of pediatric anterior cruciate ligament reconstruction in New York State

BACKGROUND

There have been no population-based studies to evaluate the rate of pediatric anterior cruciate ligament (ACL) reconstruction.

PURPOSE

The primary aim of the current study was to determine the yearly rate of ACL reconstruction over the past 20 years in New York State. Secondary aims were to determine the age distribution for ACL reconstruction and determine whether patient demographic and socioeconomic factors were associated with ACL reconstruction.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

The Statewide Planning and Research Cooperative System (SPARCS) database contains a census of all hospital admissions and ambulatory surgery in New York State. This database was used to identify pediatric ACL reconstructions between 1990 and 2009; ICD-9-CM (International Classification of Diseases, 9 Revision, Clinical Modification) and CPT-4 (Current Procedural Terminology, 4th Revision) codes were used to identify reconstructions. Patient sex, age, race, family income, education, and insurance status were assessed.

RESULTS

The rate of ACL reconstruction per 100,000 population aged 3 to 20 years has been increasing steadily over the past 20 years, from 17.6 (95% confidence interval [CI], 16.4-18.9) in 1990 to 50.9 (95% CI, 48.8-53.0) in 2009. The peak age for ACL reconstruction in 2009 was 17 years, at a rate of 176.7 (95% CI, 160.9-192.5). In 2009, the youngest age at which ACL reconstruction was performed was 9 years. The rate of ACL reconstruction in male patients was about 15% higher than in females, and ACL reconstruction was 6-fold more common in patients with private health insurance compared with those enrolled in Medicaid.

CONCLUSION

This study is the first to quantify the increasing rate of ACL reconstructions in the skeletally immature. Only ACL reconstructions were assessed, and it is possible that some ACL tears in children are not diagnosed or are treated nonoperatively. The rate of ACL tears in New York State is likely higher than the rate of reconstructions reported in this study.

SIGNIFICANCE

This study quantifies the increasing rate of ACL reconstruction in the skeletally immature and suggests that there may be some disparities in care based on insurance status.

Bone mineral density changes in the knee following anterior cruciate ligament rupture

OBJECTIVE

The pathophysiology of anterior cruciate ligament (ACL) rupture leading to knee osteoarthritis (OA) remains largely unknown. It seems that bone loss occurs after ACL rupture. The purpose of our study was to determine bone mineral density (BMD) changes in the knee after ACL rupture during 2-year follow-up period and to compare BMD changes between the injured and healthy contralateral knee.

DESIGN

Patients were included in an observational prospective follow-up study within 6 months after ACL trauma and evaluated for 2 years. Patients were treated operatively or non-operatively. At baseline and at the one- and 2-year follow-ups, BMD was measured in six regions of the tibia and femur for both knees (medial, central, lateral) using a Dual-energy X-ray Absorptiometry (DXA) scanner.

RESULTS

One hundred forty-one patients were included, with the following characteristics: 66% were male, median age at baseline was 25.3 (inter-quartile range 11.3) years, and 63% were treated operatively. After 1 year, BMD was significantly lower in all regions of the injured knee of the operatively treated patients compared to baseline. After 2 years, BMD was significantly increased, but remained lower than the baseline levels. In all regions for all measurements, the mean BMD was significantly lower in the injured knee than in the healthy contralateral knee.

CONCLUSIONS

During a 2-year follow-up period after ACL rupture, the BMD level in the injured knee was found to be lower than in the healthy contralateral knee. In operatively treated patients, the BMD decreased in the first year and increased in the second follow-up year.

Comparison of injury incidences between football teams playing in different climatic regions

Australian Football League (AFL) teams in northern (warmer) areas generally have higher rates of injury than those in southern (cooler) areas. Conversely, in soccer (football) in Europe, teams in northern (cooler) areas have higher rates of injury than those in southern (warmer) areas, with an exception being knee anterior cruciate ligament (ACL) injuries, which are more common in the southern (warmer) parts of Europe. This study examined relative injury incidence in the AFL comparing 9,477 injuries over 229,827 player-weeks from 1999–2012. There was a slightly higher injury incidence for teams from warmer parts of Australia (relative risk [RR] 1.05, 95% confidence interval [CI] 1.01–1.10) with quadriceps strains (RR 1.32, 95% CI 1.10–1.58), knee cartilage injuries (RR 1.42, 95% CI 1.16–1.74), and ankle sprains (RR 1.17, 95% CI 1.00–1.37) all being more likely in warmer region teams. Achilles injuries followed a reverse pattern, tending to be more common in cooler region teams (RR 0.70, 95% CI 0.47–1.03). In conclusion, common findings from the AFL and European soccer are that ankle sprains and ACL injuries are generally more likely in teams playing in warmer climate zones, whereas Achilles tendinopathy may be more likely in teams playing in cooler zones. These injuries may have climate or surface risk factors (possibly related to types and structure of grass and shoe-surface traction) that are universal across different football codes.

How to read post-operative radiographs and CT scans after single-bundle anterior cruciate ligament reconstruction

Reconstruction of the anterior cruciate ligament (ACL) is a well-established surgical procedure. However, post-operative imaging in the early phase is not routinely performed. The rationale for performing such imaging is to provide a baseline examination for future controls, to provide immediate feedback to surgeons regarding tunnel placement, and to assess placement of fixation devices. The purpose of this paper is to enable the reader to accurately read post-operative radiographs and CT scans after single-bundle ACL reconstruction.

Evaluation of the effectiveness of anterior cruciate ligament injury prevention programme training components: a systematic review and meta-analysis

BACKGROUND

Anterior cruciate ligament (ACL) injury prevention programmes have shown mixed results, which may be due to differing emphasis on training components. The purpose of this study was to (1) quantify the overall and relative duration of each training component encompassed within these programmes and (2) examine the effect of these durations on ACL injury rates.

METHODS

A systematic review was completed and meta-analyses performed on eligible studies to produce a pooled OR estimate of the effectiveness of these programmes. Meta-regression was used to detect any relationship that programme duration and the duration of individual training components had on ACL injury rates.

RESULTS

13 studies were included for review. Results of the meta-analyses revealed a significant reduction of injuries after preventative training programmes for all ACL injuries (pooled OR estimate of 0.612, 95% CI 0.44 to 0.85; p=0.004) and for non-contact ACL injuries (OR 0.351, 95% CI 0.23 to 0.54; p<0.001). Results of meta-regression analysis revealed that a greater duration of balance training was associated with a higher injury risk for ACL injury (p=0.04), while greater durations of static stretching was associated with a lower injury risk for non-contact ACL injuries (p=0.04).

CONCLUSIONS

While ACL prevention programmes are successful in reducing the risk of ACL injury, the ideal combination and emphasis of training components within these programmes remains unclear. Evidence indicates that greater emphases on balance training and static stretching may be associated with an increase and decrease in injury risk, respectively.

Knee injury and Osteoarthritis Outcome Score or International Knee Documentation Committee Subjective Knee Form: which questionnaire is most useful to monitor patients with an anterior cruciate ligament rupture in the short term?

PURPOSE

To evaluate which questionnaire, the Knee Injury and Osteoarthritis Outcome Score (KOOS) or the International Knee Documentation Committee Subjective Knee Form (IKDC subjective), is most useful to evaluate patients with recent anterior cruciate ligament (ACL) ruptures or those within 1 year of an ACL reconstruction.

METHODS

Patients with recent (0-6 months) ACL ruptures or those with indications for ACL reconstruction were included. All patients completed the questionnaires shortly after trauma or preoperatively and again 1 year later. The KOOS has 5 subscales, each scored separately. The IKDC subjective consists of one total score. The following measurement properties of the KOOS and IKDC subjective were assessed: content validity (n = 45), construct validity (n = 100), test-retest reliability (n = 50), and responsiveness (n = 50).

RESULTS

Regarding content validity, 2 KOOS subscales (Pain and Activities of Daily Living) were scored as nonrelevant. Two of the 18 questions on the IKDC subjective were assessed as nonrelevant. Only the KOOS subscale Sport and Recreation Function had acceptable construct validity (79% confirmation of the predefined hypotheses). None of the KOOS subscales had a sufficient score for responsiveness (<75% confirmation of the predefined hypotheses). The IKDC subjective scored acceptable for construct validity (84% confirmation of the predefined hypotheses) and responsiveness (86% confirmation of the predefined hypotheses). All KOOS subscales and the IKDC subjective had a reliability (intraclass correlation coefficient [ICC]) of 0.81 or higher.

CONCLUSIONS

The IKDC subjective is more useful than the KOOS questionnaire to evaluate both patients with recent ACL ruptures and those in the first year after ACL reconstruction.

LEVEL OF EVIDENCE

Level III, prognostic validation study.