Predictors of Revision Surgery After Anterior Cruciate Ligament Reconstruction

The effects of social determinants of health on anterior cruciate ligament injury recovery

Context

Over 200,000 anterior cruciate ligament (ACL) injuries occur in the United States each year. While many patients choose to pursue ACL reconstruction (ACLR), the impact of social determinants of health (SDOH) on outcomes is unclear.

Objective

The purpose of this study was to review and synthesize current literature to determine the impact of SDOH on outcomes following ACL reconstruction.

Data sources

A systematic search of PubMed, CINAHL, Medline, PsychINFO, and Scopus was completed.

Study selection

Articles reporting outcomes following ACLR were included if they discussed at least one SDOH and provided ACLR failure rates.

Study design

Systematic review.

Level of evidence

Level I.

Results

After screening 712 studies, 13 were found that met inclusion criteria and were analyzed. Studies commonly examined the correlations between race, income, location, education, and insurance on outcomes following ACLR. Three studies found that the ACL revision risk for Black patients compared to White patients ranged from 0.23 to 0.78, while the revision risk for Hispanic patients compared to White patients ranged from 0.7 to 0.83. One study reported finding that the odds ratio of revision for the White patients was 1.32. Another study reported no difference in revision risk based on race. Patients living in urban areas were found to have improved outcomes compared to rural areas (Mean IKDC (Urban 85.3 vs Rural 81.87) and Tegner-Lysholm (Urban 88.26 vs Rural 84.82)). Lower socioeconomic status was correlated with decreased post-operative functional scores (KOOS, Marx and IKDC).

Conclusion

Several SDOH such as White race, rural location, and low socioeconomic status may be independently correlated with worse ACLR outcomes in the form of increased revision rates or worse post-operative functional scores. However, further research is needed to better elucidate the degree of impact and interconnectedness of SDOH domains on ACLR patient outcomes.

Graft Failure and Contralateral ACL Injuries After Primary ACL Reconstruction: An Analysis of Risk Factors Using Interpretable Machine Learning

Background

Anterior cruciate ligament (ACL) reconstruction (ACLR) can be successful in restoring knee stability. However, secondary ACL injury, either through graft failure or contralateral injury, is a known complication and can significantly impact the ability of a patient to return successfully to previous activities.

Purpose

To develop and internally validate an interpretable machine learning model to quantify the risk of graft failure and contralateral ACL injury in a longitudinal cohort treated with ACLR.

Study Design

Case-control study; Level of evidence, 3.

Methods

An established geographic database of >600,000 patients was used to identify patients with a diagnosis of ACL rupture between 1990 and 2016 with a minimum 2-year follow-up. Medical records were reviewed for relevant patient information and 4 candidate machine learning algorithms were evaluated for prediction of graft failure and contralateral ACL injury in patients after ACLR as identified either on magnetic resonance imaging or via arthroscopy. Performance of the algorithms was assessed through discrimination, calibration, and decision curve analysis. Model interpretability was enhanced utilizing global variable importance plots and partial dependence curves.

Results

A total of 1497 patients met inclusion criteria. Among them, 140 (9.4%) had graft failure and 128 (8.6%) had a contralateral ACL injury after index surgery at a median follow-up of 140.7 months (interquartile range, 77.2-219.2 months). The best performing models achieved an area under the receiver operating characteristics curve of 0.70 for prediction of graft failure and 0.67 for prediction of contralateral ACL injury, outperforming a logistic regression fitted on the identical feature set. Notable predictors for increased risk of graft failure included younger age at injury, body mass index (BMI) <30, return to sports <13 months, initial time to surgery >75 days, utilization of allograft, femoral/tibial fixation with suspension/expansion devices, concomitant collateral ligament injury, and active or former smoking history. Predictors of contralateral ACL injury included greater preoperative pain, younger age at initial injury, BMI <30, active smoking history, initial time to surgery >75 days, history of contralateral knee arthroscopies, and involvement in contact sports.

Conclusion

Less than 18% of all patients who undergo ACLR should be expected to sustain either a graft failure or contralateral ACL injury. Machine learning models outperformed logistic regression and identified greater preoperative pain, younger age, BMI <30, earlier return to higher activity, and time to surgical intervention >75 days as common risk factors for both graft failure as well as contralateral ACL injury after ACLR. Surgeon-modifiable risk factors for graft failure included allograft and femoral/tibial fixation with a suspension/expansion combination.

Location and Progression of Chondral Injuries at the Time of Revision Anterior Cruciate Ligament Surgery Varies by Sex

PURPOSE

To quantify progression of chondral and meniscal injuries between primary and revision anterior cruciate ligament (ACL) surgery.

METHODS

Patients who underwent both index and revision ACL reconstruction between 2000 and 2020 at our institution were identified, and dates of injury and surgery, demographics, and clinical data were obtained from operative reports. Outerbridge grade was recorded in each compartment, along with presence and location of meniscal injury. The frequency of each injury between first and second cases was calculated. Differences in injury and progression were compared over time as well as between patient sex and age.

RESULTS

The study included 189 patients (96 female, 93 male). Age at first surgery was 31.7 ± 13.2 years. Mean time to second injury was 3.3 ± 3.0 years. In total, 116 patients had a new or previous chondral injury (odds ratio, 1.6; 95% CI, 1.2-2.1). The medial femoral condyle (31%) and the patella (21%) accounted for the highest proportion of new injury to articular surfaces, whereas new injury to menisci was comparable between the medial (25%) and lateral (23%) meniscus. At the time of revision ACL reconstruction, females had a high prevalence of chondral injuries to the lateral compartment, whereas males had a high prevalence of chondral injury to the medial femoral condyle. The prevalence of new chondral injuries was comparable between sexes, with males having a slightly higher proportion. While time between surgeries, sex, and age had graphical evidence of moderating risk, the effects were small and imprecise.

CONCLUSIONS

Revision ACL reconstruction carried a 1.6 increase in the odds for new or progressive chondral lesions in our cohort. At the time of revision, females had a relatively higher proportion of lateral-sided chondral injuries, whereas males had a relatively higher proportion of medial femoral condyle injuries. The greatest increase in the prevalence of new and progressive lesions was observed in the medial femoral condyle and trochlea. This progression appeared to be moderated by time between surgeries, patient sex, and age; however, the differences were small and imprecise.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Factors associated with increased 30-day re-operation risk in anterior cruciate ligament reconstruction

BACKGROUND

Revision surgery following isolated anterior cruciate ligament reconstruction (ACLR) has often focused on mid- to long-term revisions due to re-rupture, while short-term 30-day revision is a rare, but underappreciated entity. This study aims to characterize incidence and risk factors for reoperations following isolated ACLR.

METHODS

This is a retrospective case-control analysis of the American College of Surgeons National Surgical Quality Improvement Program Database (NSQIP) database from 2005 to 2017. Current Procedural Terminology codes were used to identify elective isolated ACLR patients. Patients undergoing reoperations were analyzed using bivariate analysis against their respective perioperative variables. Multivariate stepwise logistic regression was used to identify independent risk factors for reoperations after ACLR.

RESULTS

12,790 patients were included in the study. 37.0% of patients were female. Mean age was 32.2+/-10.7 years and mean body mass index (BMI) was 27.8+/-6.5 kg/m2, with 28.9% of patients with BMI > 30. The most frequently reported reason for reoperation based on CPT and ICD-9/10 codes was postoperative infection (0.5%). Overall reoperation rate was approximately 0.5%. Multivariate analysis identified operative time >1.5 h (OR 2.6 [95% CI; 1.5-4.4]), dependent functional status (OR 14.0 [1.4-141.6]), and adjunctive anesthesia (OR 2.4 [95% CI; 1.1-5.0]) as independent risk factors for reoperation. Female sex was a protective factor against reoperations (OR 0.6 [0.3-0.98]).

CONCLUSION

Primary, isolated ACLR is associated with extremely low rates of short-term reoperations. Operative time >1.5 h, dependent functional status, and adjunctive anesthesia were independent risk factors for reoperation and female sex was a protective factor against reoperation.

LEVEL OF EVIDENCE

Level III. Retrospective cohort study.

Difference of Knee Strength Recovery Between Revision and Primary ACL Reconstruction

Different grafting procedures are available to restore knee stability after revision anterior cruciate ligament (ACL) reconstruction. We compared knee strength recovery between ACL revision surgery and primary reconstruction. One hundred and ten patients with ACL revision surgery were matched with 110 patients with primary reconstruction based on the graft procedure. The isokinetic knee strength had been assessed for the first 9 months post-surgery. Knee laxity, function, and activity score were also evaluated. Limb symmetry index for knee extensor and flexor strength was not different at 4-, 6- and 9-months post-surgery between revision surgery and primary reconstruction. These results depended on ipsilateral or contralateral graft choice. Ipsilateral hamstring tendon (HT) and contralateral bone-patellar-tendon-bone (BPTB) graft procedures were similar for a revision of a BPTB graft failure. Contralateral HT procedure was better than ipsilateral BPTB procedure for a revision of a HT graft failure. The early recovery of isokinetic knee strength after ACL revision surgery regardless of the HT or BPTB procedures, was similar to the recovery after primary ACL reconstruction with the same graft technique. These results apparently depended on a temporary quadriceps arthrogenic muscle inhibition and on a persistent donor site morbidity, concerning the new and the previous grafts, respectively.

Anterior Cruciate Ligament Repair Using a Re-tensionable All-Suture Construct

Anterior cruciate ligament (ACL) tears are among the most common injuries to the knee. With recent improvements in imaging that allow for more precise identification of ACL tear patterns, improved techniques for repair, and advancements in biological augmentation, there has been a re-emerging interest in primary ACL repair, especially for acute proximal ACL tears. This article aims to describe a surgical technique for primary ACL repair using a re-tensionable all-suture-based construct.

Increased age and modified fragility index increases risk of short-term complications after anterior cruciate ligament reconstruction surgery

BACKGROUND

Large data analysis of anterior cruciate ligament reconstruction (ACLR) short-term complications on age will help surgeons stratify and counsel at-risk patients. The purpose of this study is to assess if older patients are at greater risk for short-term complications after ACLR.

METHODS

This retrospective cohort study included patients who underwent elective ACLR with or without concomitant meniscal procedures in the National Surgical Quality Improvement Program from 2005 to 2017. Patients were divided into age groups 16-30, 31-45, and > 45. Modified fragility index-5 (mFI-5), demographics and short-term outcomes were examined with bivariate and multivariate analysis to determine if age was a risk factor for complications.

RESULTS

A total of 23,581 patients (35.4% female) were included in this analysis. Mean age was 32.1 ± 10.8 years. Older patients had higher mFI-5 scores (p < 0.001), shorter operative times (p < 0.001), lower use of only general anesthesia (p < 0.001). The oldest patients had similar rates of complications as the two younger groups. Older age was an independent risk factor for VTE, but decreased risk of prolonged operations. A mFI-5 > 0 increased risk factors for readmission (Odds ratio 2.2, P = 0.006). Infection was the most common cause 30-day readmissions (40/135, 29.6%).

CONCLUSION

In the early postoperative period, older age is an independent risk factor for VTE and younger age is a significant factor for prolonged surgeries. Having an mFI-5 > 0 increased risk factors for readmission.

Risk Factors for Revision or Rerupture After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

The rerupture or need for revision after anterior cruciate ligament reconstruction (ACLR) is a serious complication. Preventive strategies that target the early identification of risk factors are important to reduce the incidence of additional surgery.

PURPOSE

To perform a systematic review and meta-analysis to investigate risk factors for revision or rerupture after ACLR.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

Literature searches were performed in PubMed, Embase, and Web of Science from database inception to November 2021 and updated in January 2022. Quantitative, original studies reporting potential adjusted risk factors were included. Odds ratios (ORs) were calculated for potential risk factors.

RESULTS

A total of 71 studies across 13 countries with a total sample size of 629,120 met the inclusion criteria. Fifteen factors were associated with an increase in the risk of revision or rerupture after ACLR: male sex (OR, 1.27; 95% CI, 1.14-1.41), younger age (OR, 1.07; 95% CI, 1.05-1.08), lower body mass index (BMI) (OR, 1.03; 95% CI, 1.00-1.06), family history (OR, 2.47; 95% CI, 1.50-4.08), White race (OR, 1.32; 95% CI, 1.08-1.60), higher posterolateral tibial slope (OR, 1.15; 95% CI, 1.05-1.26), preoperative high-grade anterior knee laxity (OR, 2.30; 95% CI, 1.46-3.64), higher baseline Marx activity level (OR, 1.07; 95% CI, 1.02-1.13), return to a high activity level/sport (OR, 2.03; 95% CI, 1.15-3.57), an ACLR within less than a year after injury (OR, 2.05; 95% CI, 1.81-2.32), a concomitant medial collateral ligament (MCL) injury (OR, 1.62; 95% CI, 1.31-2.00), an anteromedial portal or transportal technique (OR, 1.36; 95% CI, 1.22-1.51), hamstring tendon (HT) autografts (vs bone-patellar tendon-bone [BPTB] autografts) (OR, 1.60; 95% CI, 1.40-1.82), allografts (OR, 2.63; 95% CI, 1.65-4.19), and smaller graft diameter (OR, 1.21; 95% CI, 1.05-1.38). The other factors failed to show an association with an increased risk of revision or rerupture after ACLR.

CONCLUSION

Male sex, younger age, lower BMI, family history, White race, higher posterolateral tibial slope, preoperative high-grade anterior knee laxity, higher baseline Marx activity level, return to a high activity level/sport, an ACLR within less than a year from injury, a concomitant MCL injury, an anteromedial portal or transportal technique, HT autografts (vs BPTB autografts), allografts, and smaller graft diameter may increase the risk of revision or rerupture after ACLR. Raising awareness and implementing effective preventions/interventions for risk factors are priorities for clinical practitioners to reduce the incidence of revision or rerupture after ACLR.

Factors Affecting Graft Remodeling and Anterior Cruciate Ligament Reconstruction: MRI Study of 180 Knees

BACKGROUND

Several factors affect the retear rate after anterior cruciate ligament (ACL) reconstruction, but there are few data on which factors affect graft remodeling.

PURPOSE

To determine which factors are associated with the remodeling of an ACL graft.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A retrospective longitudinal study was conducted to investigate the relationship between various exposure factors and the occurrence of an "event": graft remodeling measured with the signal-to-noise quotient (SNQ). Data were collected prospectively and analyzed retrospectively for this study. The endpoint was the SNQ on magnetic resonance imaging at postoperative 1 year. The effect of the following parameters on SNQ was investigated: sex, smoking habits, age at surgery, body mass index, time to surgery, time to return to sports, type of sport (in-line, pivot, contact), type of graft (free semitendinosus [ST] or attached ST), and addition of lateral tenodesis.

RESULTS

An overall 180 patients were enrolled (90 with each technique). The following factors were significantly and independently associated with the SNQ: attached ST graft (β = -2.624668; P < .001), age at the time of surgery (β = -0.7948476; P = .012), and time elapsed between the injury event and surgery (β = -0.7137424; P = .046).

CONCLUSION

Leaving the ST graft attached distally, being older at the time of surgery, and having more time elapse between the injury event and ACL reconstruction surgery were significantly associated with better graft remodeling.

Incidence and risk factors for revision and contralateral anterior cruciate ligament reconstruction: A population-based retrospective cohort study

There is a limited data on epidemiology of primary and recurrent anterior cruciate ligament reconstruction (ACLR) in Canada. The objectives of this study were to examine the incidence and factors associated with recurrent ACLR (revision and contralateral ACLR) in a western Canadian province of Alberta. We conducted a retrospective cohort study with an average follow up of 5.7 years. Albertans aged 10 to 60 years with a history of primary ACLR between 2010/11 to 2015/16 were included in the study. Participants were followed up until March 2019 to observe outcomes: Ipsilateral revision ACLR and contralateral ACLR. Kaplan Meir approach was used to estimate event free survival and Cox proportional hazard regression analysis was conducted to identify associated factors. Of the total participants with a history of primary ACLR on a single knee (n = 9292), n = 359, 3.9% (95% confidence interval: 3.5-4.3) underwent a revision ACLR. A similar proportion among those having primary ACLR on either knee (n = 9676), n = 344, 3.6% (95% confidence interval: 3.2-3.9) underwent a contralateral primary ACLR. Young age (<30 years) was associated with increased risk of contralateral ACLR. Similarly, young age (<30 years), having initial primary ACLR in winter and having allograft were associated with a risk of revision ACLR. Clinicians can use these findings in their clinical practice and designing rehabilitation plans as well as to educate patients about their risk for recurrent anterior cruciate ligament tear and graft failure.

American Academy of Orthopaedic Surgeons Clinical Practice Guideline Case Study: Management of Anterior Cruciate Ligament Injuries

Considering the frequency of anterior cruciate ligament (ACL) tears, optimal management of these injuries was the subject of a 2022 clinical practice guideline update from The American Academy of Orthopaedic Surgeons (AAOS) with input from representatives from the American Orthopaedic Society for Sports Medicine, the Pediatric Orthopaedic Society of North America, the American Orthopaedic Society for Sports Medicine, the American Medical Society for Sports Medicine, the American Academy of Physical Medicine and Rehabilitation, and the American College of Emergency Physicians. The eight recommendations and seven options to guide orthopaedic surgeons and other physicians managing patients with these anterior cruciate ligament injuries are based on the best current available evidence. The cases presented in this article are examples designed to demonstrate the clinical application of these guidelines.

Return to Sports: A Risky Business? A Systematic Review with Meta-Analysis of Risk Factors for Graft Rupture Following ACL Reconstruction

BACKGROUND

The risk of sustaining a graft rupture after anterior cruciate ligament reconstruction (ACLR) is high. Contributing risk factors are, however, still not clearly identified.

OBJECTIVE

The aim of this systematic review was to identify and quantify risk factors for graft rupture after ACLR.

METHODS

A systematic review with meta-analysis (PROSPERO CRD42020140129) based on PRISMA guidelines was performed. MEDLINE, CINAHL and EMBASE were searched from inception to September 2021. Prospective and retrospective studies addressing risk factors for graft rupture after ACLR in males/females of all ages were considered. Meta-analyses using a random effect model (effect measure: odds ratio [OR] with 95% confidence interval [CI]) were performed. The GRADE tool was used to assess evidence quality.

RESULTS

Following full-text screening of 310 relevant papers, 117 were eventually included, incorporating up to 133,000 individuals in each meta-analysis. Higher Tegner activity level (≥ 7 vs < 7) at primary injury (OR 3.91, 95% CI 1.69-9.04), increased tibial slope (degrees) (OR 2.21, 95% CI 1.26-3.86), lower psychological readiness to return to sport (RTS) (OR 2.18, 95% CI 1.32-3.61), early surgery (< 12 vs ≥ 12 months) (OR 1.87, 95% CI 1.58-2.22), RTS (pre-injury level) (OR 1.87, 95% CI 1.21-2.91) and family history of ACL injury (OR 1.76, 95% CI 1.34-2.31) were all associated with increased odds of graft rupture. Higher age (OR 0.47, 95% CI 0.39-0.59), female sex (OR 0.88, 95% CI 0.79-0.98), fewer self-reported knee symptoms pre-reconstruction (OR 0.81, 95% CI 0.69-0.95) and concomitant cartilage injuries (OR 0.70, 95% CI 0.62-0.79) instead decreased the odds. Meta-analysis revealed no association between body mass index, smoking, joint laxity, RTS time, knee kinematics, muscle strength or hop performance and graft rupture.

CONCLUSION

Conspicuous risk factors for graft rupture were mainly sports and hereditary related. Few studies investigated function-related modifiable factors or included sports exposure data.

Differentiation in Posterior Tibial Slope by Sex, Age, and Race: A Cadaveric Study Utilizing 3-Dimensional Computerized Tomography

BACKGROUND

Posterior tibial slope (PTS) has recently gained increased attention for its possible role in anterior cruciate ligament and posterior cruciate ligament injury. The possible differences among age, sex, and ethnicity in PTS have not yet been reported.

PURPOSE

To describe demographic variances of proximal tibial anatomy and to detect differences in regard to ethnicity, sex, and age.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

In total, 250 cadaveric specimens with full-body computerized tomography scans from the New Mexico Descendant Imaging Database were randomly selected (inclusion/exclusion criteria: older than 18 years, complete imaging of the knee without previous surgery or arthroplasty) and reviewed by 3 independent observers measuring medial posterior tibial slope (MPTS), lateral posterior tibial slope (LPTS), and global posterior tibial slope (PTS), which was calculated as the mean of the MPTS and LPTS. Individuals were evenly divided among male and female and ethnicities/races: African American/Black, Asian American, Hispanic, Native American, and White. Intraclass correlation coefficient was calculated for interobserver reliability and analysis of variance statistical testing to determine statistical significance between groups. Fisher exact test was also used to understand PTS differences among ethnicities when looking at clinically significant values for potential ligamentous injury.

RESULTS

Measurements were obtained from 250 specimens with a mean age of 49.4 years (range, 19 to 103 years). The mean PTS was 8.92° (range, -9.4° to 14.95°). Asian Americans had a 1.7° greater mean MPTS than Whites (P = .016), and African Americans/Blacks had a 1.6° greater mean PTS than Whites (P = .022). No difference in mean PTS was seen between age and sex. When looking at clinically significant PTS, 61 (24.4%) individuals had tibial slopes <6° or >12°, 32 (12.8%) and 29 (11.6%), respectively. Statistically significant differences were seen among ethnicities with PTS <6° (P = .017) but not with PTS >12° (P = .106). No sex-based differences were seen in the percentage of specimens with a PTS of >12° or <6°.

CONCLUSION

Among ethnicities, African Americans/Blacks and Asian Americans have increased PTS in comparison with Whites. Nearly 25% of individuals have clinically significant slopes of <6° or >12°, with no difference in tibial slope among sex or age groups.

No Difference in Complication Rates or Patient-Reported Outcomes Between Bone–Patella Tendon–Bone and Quadriceps Tendon Autograft for Anterior Cruciate Ligament Reconstruction

Purpose

To compare subjective outcomes and complications of anterior cruciate ligament reconstruction (ACLR) using either bone–patellar tendon–bone (BPTB) or quadriceps tendon (QT) autograft.

Methods

A retrospective analysis of prospectively collected data identified consecutive cohorts of patients undergoing ACLR with either BPTB or QT autograft. Patients with less than 12-month follow-up and those undergoing concomitant osteotomies, cartilage restoration, and/or other ligament reconstruction procedures were excluded. Pre- and postsurgical patient-reported outcomes including International Knee Documentation Committee, Knee Injury and Osteoarthritis Outcome Score, Patient-Reported Outcomes Measurement Information System (PROMIS), Single Assessment Numeric Evaluation, Tegner, and Marx were compared between groups. Complications requiring reoperation were recorded.

Results

One hundred nineteen patients met inclusion criteria, including 39 QT autografts and 80 BPTB autografts. Demographic information was comparable between groups. Mean follow-up was comparable between groups (QT 22.4 ± 10.6 months vs BPTB 28.5 ± 18.5 months, P = .06). At minimum 12-month follow-up (range 12.0-100.8 months), patients in both groups demonstrated statistically significant improvements in International Knee Documentation Committee (QT 60.0%, P < .0001; BPTB 57.7%, P < .0001), all Knee Injury and Osteoarthritis Outcome Score domains, PROMIS Mobility T-Score (QT 27.2%, P = .0001; BPTB 23.2%, P < .0001), PROMIS Global Physical Health (QT 14.4%, P = .002; BPTB 13.4%, P = .001), PROMIS Physical Function (QT 29.6%, P < .0001; BPTB 37.1%, P < .0001), PROMIS Pain Interference (QT –16.5%, P < .0001; BPTB –20.8%, P < .0001), Single Assessment Numeric Evaluation, (QT 76.9%, P < .0001; BPTB 73.3%, P < .0001), Tegner (QT 92.9%, P = .0002; BPTB 101.4%, P < .0001), and Marx (QT –26.6%, P = .02; BPTB –32.0%, P = .0002) with no statistically significant differences between the 2 groups. Overall postoperative reoperation rate did not differ between groups (QT 12.8% vs BPTB 23.8%, P = .2). Revision ACL reconstruction rate did not differ between groups (QT 5.1% vs BPTB 7.5%, P = .6).

Conclusions

Patients undergoing autograft ACLR with either BPTB or QT demonstrated significant subjective improvements in patient-reported outcomes from preoperative values and no statistically significant differences in outcomes between the groups. Complication and revision ACLR rates were similar between the 2 groups.

Level of Evidence

III, retrospective cohort study.

Disparities in ACL Reconstruction: the Influence of Gender and Race on Incidence, Treatment, and Outcomes

PURPOSE OF REVIEW

Anterior cruciate ligament (ACL) rupture is a common injury that has important clinical and economic implications. We aimed to review the literature to identify gender, racial and ethnic disparities in incidence, treatment, and outcomes of ACL injury.

RECENT FINDINGS

Females are at increased risk for ACL injury compared to males. Intrinsic differences such as increased quadriceps angle and increased posterior tibial slope may be contributing factors. Despite lower rates of injury, males undergo ACL reconstruction (ACLR) more frequently. There is conflicting evidence regarding gender differences in graft failure and ACL revision rates, but males demonstrate higher return to sport (RTS) rates. Females report worse functional outcome scores and have worse biomechanical metrics following ACLR. Direct evidence of racial and ethnic disparities is limited, but present. White athletes have greater risk of ACL injury compared to Black athletes. Non-White and Spanish-speaking patients are less likely to undergo ACLR after ACL tear. Black and Hispanic youth have greater surgical delay to ACLR, increased risk for loss to clinical follow-up, and less physical therapy sessions, thereby leading to greater deficits in knee extensor strength during rehabilitation. Hispanic and Black patients also have greater risk for hospital admission after ACLR, though this disparity is improving. Females have higher rates of ACL injury with inconclusive evidence on anatomic predisposition and ACL failure rate differences between genders. Recent literature has suggested inferior RTS and functional outcomes following ACLR in females. Though there is limited and mixed data on incidence and outcome differences between races and ethnic groups, recent studies suggest there may be disparities in those who undergo ACLR and time to treatment.

A Systematic Review of Risk Factors for Anterior Cruciate Ligament Reconstruction Failure

Although most studies have introduced risk factors related to anterior cruciate ligament reconstruction failure, studies on combinations of high-risk factors are rare. To provide a systematic review of the risk factors of anterior cruciate ligament reconstruction failure to guide surgeons through the decision-making process, an extensive literature search was performed of the Medline, Embase and Cochrane Library databases. Studies published between January 1, 2009, and September 19, 2019, regarding the existing evidence for risk factors of anterior cruciate ligament reconstruction failure or graft failure were included in this review. Study quality was evaluated with the quality index. Ultimately, 66 articles met our criteria. There were 46 cases classified as technical factors, 21 cases as patient-related risk factors, and 14 cases as status of the knee joint. Quality assessment scores ranged from 14 to 24. This systematic review provides a comprehensive summary of the risk factors for anterior cruciate ligament reconstruction failure, including technical factors, patient-related factors, and the factors associated with the status of the knee joint. Emphasis should be placed on avoiding these high-risk combinations or correcting modifiable risk factors during preoperative planning to reduce the rate of graft rupture and anterior cruciate ligament reconstruction failure.

The Impact of Resident Involvement on Surgical Outcomes following Anterior Cruciate Ligament Reconstruction

Hands-on participation in the operating room (OR) is an integral component of surgical resident training. However, the implications of resident involvement in many orthopaedic procedures are not well defined. This study aims to assess the effect of resident involvement on short-term outcomes following anterior cruciate ligament reconstruction (ACLR). The National Surgical Quality Improvement Program (NSQIP) database was queried to identify all patients who underwent ACLR from 2005 to 2012. Demographic variables, resident participation, 30-day complications, and intraoperative time parameters were assessed for all cases. Resident and nonresident cases were matched using propensity scores. Outcomes were analyzed using univariate and multivariate regression analyses, as well as stratified by resident level of training. Univariate analysis of 1,222 resident and 1,188 nonresident cases demonstrated no difference in acute postoperative complication rates between groups. There was no significant difference in the incidence of overall complications based on resident level of training (p = 0.109). Operative time was significantly longer for cases in which a resident was involved (109.5 vs. 101.7 minutes; p < 0.001). Multivariate analysis identified no significant predictors of major postoperative complications, while patient history of chronic obstructive pulmonary disease was the only independent risk factor associated with minor complications. Resident involvement in ACLR was not associated with 30-day complications despite a slight increase in operative time. These findings provide reassurance that resident involvement in ACLR procedures is safe, although future investigations should focus on long-term postoperative outcomes.

Incorporation of Whipstitch Suture in Tibial Interference Fixation Improves Pullout in Anterior Cruciate Ligament Soft Tissue Grafts

INTRODUCTION

Interference screw fixation of soft tissue grafts is commonly used in anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to determine whether including suture material at the graft-screw interface affects ultimate fixation strength of soft tissue grafts using a tibialis anterior tendon allograft model.

MATERIALS AND METHODS

Forty fresh-frozen human tibialis anterior tendon allografts were fixed to rigid polyurethane foam simulating the tibial tunnel. Twenty grafts underwent fixation with interference screws and 20 with interference bolts. Within each group, 10 grafts had suture in contact with either the screw or bolt. A load-to-failure test was then performed at a rate of 200 mm/min.

RESULTS

The group of allografts with sutures in the tibial tunnel had significantly higher load to failure than the group without sutures. Using interference screw fixation, failure load of the grafts without sutures in the tunnel (535.2 ± 73.40 N) was significantly lower (P = .001) than with sutures in the tunnel (696.3 ± 110.0 N). Using interference bolt fixation, failure load of the grafts without sutures in the tunnel (613.0 ± 83.46 N) was significantly lower (P <.0001) than with sutures in the tunnel (845.8 ± 87.23 N).

CONCLUSIONS

In a biomechanical model, suture within the tibial tunnel enhances fixation strength with both interference screw and bolt fixation for soft tissue tibialis anterior allografts. Additionally, there was no difference in load to failure when comparing failure of a screw with suture in the tunnel with an interference bolt without suture. Due to improved biomechanical properties, incorporation of suture in the bone-graft interface should be considered when performing soft tissue ACL allograft reconstructions. Failure at the tibial bone-graft interface is a known complication of ACL reconstruction, and incorporation of suture within the interface should be considered for improved biomechanical properties.

Failed Meniscal Repairs After Anterior Cruciate Ligament Reconstruction Increases Risk of Revision Surgery

Background:

Failed anterior cruciate ligament (ACL) reconstruction (ACLR) can lead to reduced quality of life because of recurrent episodes of instability, restrictions in level of activity, and development of osteoarthritis. A profound knowledge of the causes of a failed surgery can ultimately help improve graft survival rates.

Purpose:

To investigate the patient-related risks of inferior outcomes leading to revision surgery after ACLR.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

From a prospective cohort of primary ACLRs performed at a single center, patients who required later revision surgery were matched with a control group of uneventful primary ACLRs. Patient characteristics, data from the preoperative examinations, KT-1000 arthrometer laxity testing, Tegner activity scale, International Knee Documentation Committee subjective score, Knee injury and Osteoarthritis Outcome Score, and perioperative data from the initial surgery were included.

Results:

A total of 100 revision cases and 100 matched controls, with a median follow-up time of 11 years, were included in the study. Those who had undergone revision surgery were younger at the time of reconstruction and had a shorter time from injury to surgery than their matched controls (P = .006). The control group—of uneventful ACLRs—had a higher incidence of meniscal repair at reconstruction (P = .024). Also, the revision group more frequently experienced later failure of the previous meniscal repair (P = .004). Surgeon experience was not found to affect the risk of revision ACL surgery. Those who had undergone ACL revision surgery had more frequently received a hamstring tendon graft size of <8 mm (P = .018) compared with the controls.

Conclusion:

The current study demonstrated that failed meniscal repair and a hamstring tendon graft size of <8 mm were associated with primary ACLR failure. Also, younger age at the time of surgery and shorter time from injury to surgery were found to affect the risk of undergoing revision ACL surgery.

One sixth of primary anterior cruciate ligament reconstructions may undergo reoperation due to complications or new injuries within 2 years

PURPOSE

To analyse the incidence, types and risk factors for reoperation within 2 years of primary anterior cruciate ligament reconstruction (ACLR).

METHODS

Our clinic registry was used to identify primary ACLRs, performed from 2005 to 2015, and reoperations performed on the ipsilateral knee within 2 years at our institution. Reoperations were identified using procedural codes and analysis of medical records. A logistic regression analysis was used to evaluate risk factors for reoperation.

RESULTS

A total of 6030 primary ACLRs were included. A total of 1112 (18.4%) reoperations performed on 1018 (16.9%) primary ACLRs were identified. The most common reoperations were screw removal (n = 282, 4.7%), meniscus procedures (n = 238, 3.9%), cyclops removal/notchplasty (n = 222, 3.7%) and reoperations due to graft rupture (n = 146, 2.4%), including revision ACLR. Age < 30 years (OR 1.57; 95% CI 1.37-1.80; P < 0.001), female gender (OR 1.33; 95% CI 1.17-1.51; P < 0.001), medial meniscus repair (OR 1.55; 95% CI 1.23-1.97; P < 0.001), lateral meniscus resection (OR 1.26; 95% CI 1.07-1.49; P = 0.005) and lateral meniscus repair (OR 1.38; 95% CI 1.03-1.85; P = 0.02) at primary ACLR were found to be risk factors for reoperation.

CONCLUSION

One sixth of all primary ACLRs underwent reoperation due to complications or new injuries within 2 years. The most common reoperations were screw removal, meniscus procedures, cyclops removal/notchplasty and reoperations due to graft rupture, including revision ACLR. Younger age (< 30 years), female gender, medial meniscus repair and lateral meniscus resection or repair at primary ACLR were associated with an increased risk of reoperation. This study provides clinicians with important data to inform patients about the short-term reoperation rates, the most common reoperation procedures and risk factors for reoperation after primary ACLR.

LEVEL OF EVIDENCE

III.

Primary ACL reconstruction using the LARS device is associated with a high failure rate at minimum of 6-year follow-up

PURPOSE

The Ligament Augmentation and Reconstruction System (LARS^®) is a synthetic ligament consisting of fibres made of polyethylene terephthalate. Despite the LARS being used as an anterior cruciate ligament (ACL) device for nearly 30 years and the well-documented complications from earlier synthetic ligament designs, there is a paucity of published medium- to long-term results. The aim of this study is to report the clinical and functional outcomes after ACL reconstruction using the LARS at a minimum follow-up of 6 years.

METHODS

Results of a single surgeon's entire cohort of 55 patients who underwent primary LARS ACL surgery were reviewed at a median of 7.8 years (6.0-9.4). Patient-reported outcome measures including the International Knee Documentation Committee (IKDC) score and 36-Item Short Form Health Survey (SF-36) were collected and clinical assessment consisted of range of motion (ROM) and the KT-1000 arthrometer to assess the side-side difference in the operative and non-operative knee. Mechanical failures of the graft were confirmed at revision surgery and a survivorship analysis was performed using the Kaplan-Meier method.

RESULTS

The overall mechanical failure rate was 17/51 (33.3%) with ruptures occurring at a median 3.9 years (0.6-8.8 years) following primary LARS ACL surgery. Secondary operative procedures were performed in 39.2% of patients. For intact grafts, there was no statistically significant difference is side-to-side ROM or anterior knee laxity and subjective scores revealed a median IKDC subjective score of 85.1 (26.4-100) and SF-36 physical component score of 94.1.

CONCLUSION

The rates of LARS ACL construct failure (33.3%) in this cohort are high and based on these results the LARS should not be considered as a graft option for primary ACL reconstruction.

LEVEL OF EVIDENCE

III, cohort study.

The Association Between Race/Ethnicity and Revision Following ACL Reconstruction in a Universally Insured Cohort

BACKGROUND

There have been few large studies involving multiethnic cohorts of patients treated with anterior cruciate ligament reconstruction (ACLR), and therefore, little is known about the role that race/ethnicity may play in the differential risk of undergoing revision surgery following primary ACLR. The purpose of this study was to evaluate whether differences exist by race/ethnicity in the risk of undergoing the elective procedure of aseptic revision in a universally insured cohort of patients who had undergone ACLR.

METHODS

This was a retrospective cohort study conducted using our integrated health-care system's ACLR registry and including primary ACLRs from 2008 to 2015. Race/ethnicity was categorized into the following 4 groups: non-Hispanic white, black, Hispanic, and Asian. Multivariable Cox proportional-hazard models were used to evaluate the association between race/ethnicity and revision risk while adjusting for age, sex, highest educational attainment, annual household income, graft type, and geographic region in which the ACLR was performed.

RESULTS

Of the 27,258 included patients,13,567 (49.8%) were white, 7,713 (28.3%) were Hispanic, 3,725 (13.7%) were Asian, and 2,253 (8.3%) were black. Asian patients (hazard ratio [HR] = 0.72; 95% confidence interval [CI] = 0.57 to 0.90) and Hispanic patients (HR = 0.83; 95% CI = 0.70 to 0.98) had a lower risk of undergoing revision surgery than did white patients. Within the first 3.5 years postoperatively, we did not observe a difference in revision risk when black patients were compared with white patients (HR = 0.86; 95% CI = 0.64 to 1.14); after 3.5 years postoperatively, black patients had a lower risk of undergoing revision (HR = 0.23; 95% CI = 0.08 to 0.63).

CONCLUSIONS

In a large, universally insured ACLR cohort with equal access to care, we observed Asian, Hispanic, and black patients to have a similar or lower risk of undergoing elective revision compared with white patients. These findings emphasize the need for additional investigation into barriers to equal access to care. Because of the sensitivity and complexity of race/ethnicity with surgical outcomes, continued assessment into the reasons for the differences observed, as well as any differences in other clinical outcomes, is warranted.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Rates of Adverse Outcomes and Revision Surgery After Anterior Cruciate Ligament Reconstruction: A Study of 104,255 Procedures Using the National Hospital Episode Statistics Database for England, UK

BACKGROUND

After an anterior cruciate ligament (ACL) injury, ACL reconstruction is an elective procedure, and therefore, an understanding of the attributable risk from undergoing ACL reconstruction is necessary for patients to make a fully informed treatment decision.

PURPOSE

To determine the absolute risk of adverse outcomes including reoperation after ACL reconstruction with comparison, where possible, to the rate of adverse events reported in the general population.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

National hospital data on all ACL reconstructions performed in England between April 1, 1997, and March 31, 2017, were analyzed. Revision cases, bilateral procedures within 6 months, and cases with concurrent cartilage or multiple ligament surgery were excluded. The primary outcome was the occurrence of at least 1 serious complication (myocardial infarction, stroke, pulmonary embolism, infection requiring surgery, fasciotomy, neurovascular injury, or death) within 90 days. Additionally, 5-year rates of revision ACL reconstruction, contralateral ACL reconstruction, and meniscal surgery were investigated.

RESULTS

There were 133,270 ACL reconstructions performed, of which 104,255 were eligible for analysis. Within 90 days, serious complications occurred in 675 (0.65% [95% CI, 0.60-0.70]), including 494 reoperations for infections (0.47% [95% CI, 0.43-0.52]) and 129 for pulmonary embolism (0.12% [95% CI, 0.10-0.15]). Of 54,275 procedures with at least 5 years' follow-up, 1746 (3.22% [95% CI, 3.07-3.37]) underwent revision ACL reconstruction in the same knee, 1553 underwent contralateral ACL reconstruction (2.86% [95% CI, 2.72-3.01]), and 340 underwent meniscal surgery (0.63% [95% CI, 0.56-0.70]). The overall risk of serious complications fell over time (adjusted odds ratio [OR], 0.96 per year [95% CI, 0.95-0.98]); however, older patients (adjusted OR, 1.11 per 5 years [95% CI, 1.07-1.16]) and patients with a greater modified Charlson Comorbidity Index (adjusted OR, 2.41 per 10 units [95% CI, 1.65-3.51]) were at a higher risk. For every 850 (95% CI, 720-1039) ACL reconstructions, 1 pulmonary embolism could be provoked. For every 213 (95% CI, 195-233), 1 native knee joint infection could be provoked.

CONCLUSION

The overall risk of adverse events after ACL reconstruction is low; however, some rare but serious complications, including infections or pulmonary embolism, may occur. Around 3% of patients undergo further ipsilateral or contralateral ACL reconstruction within 5 years. These data will inform shared decision making between clinicians and patients considering their treatment options.

Femoral Tunnel Drilling Method: Risk of Reoperation and Revision After Anterior Cruciate Ligament Reconstruction

BACKGROUND

The femoral tunnel in anterior cruciate ligament reconstruction (ACLR) can be created by the transtibial (TT) or tibial-independent (TI) methods. An anatomically located femoral tunnel can be more consistently achieved by TI methods, which include the anteromedial portal and lateral (outside-in, retrodrill) techniques. Nonanatomic graft placement in ACLR can result in postoperative instability and meniscal or chondral injury. An anatomically located graft is subjected to higher postoperative physiologic forces than one placed nonanatomically.

PURPOSE

To examine isolated primary ACLR and determine the risk of aseptic revision and reoperation based on femoral tunnel drilling method.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

The ACLR registry of an integrated US health care system was used to identify primary isolated unilateral ACLRs from 2009 to 2014. Multivariable Cox proportional hazard regression models were used to evaluate risk for aseptic revision for graft failure and aseptic reoperation for meniscal or chondral injury according to femoral tunnel drilling method: TI versus TT. Models included age, sex, body mass index (BMI), race, graft type, and femoral fixation type as covariates.

RESULTS

The cohort included 19,059 patients with primary ACLR. The mean age was 28.9 years (SD, 11.5), 6991 patients (36.8%) were younger than 22 years, 11,795 patients (61.9%) were male, 7648 patients (40.1%) had a BMI less than 25 kg/m², 8913 patients (46.8%) were white, and 7357 patients (38.6%) received an allograft. Median follow-up was 2.30 years (interquartile range, 1.08-3.77). TI techniques were used for 12,342 (64.8%) of the ACLRs, and the TT method was used for 6717 (35.2%). Use of TI techniques increased from 33.6% of all ACLRs in 2009 to 83.4% in 2014. After adjustment for covariates, the TI group had a higher risk for aseptic revision than the TT group (hazard ratio [HR], 1.28; 95% CI, 1.04-1.56), and this risk was 1.41 times higher in patients younger than 22 years specifically. The 5-year cumulative reoperation probability was lower in the TI group (4.50%; 95% CI, 3.78%-5.36%) compared with the TT group (5.06%; 95% CI, 4.31-5.94%). After adjustment for the covariates, no difference in risk for aseptic reoperation was observed (HR, 1.08; 95% CI, 0.85-1.39).

CONCLUSION

In the largest known study of its type examining femoral tunnel drilling method for primary ACLR, after adjustment for age, sex, BMI, race, graft type, and femoral fixation, TI techniques were found to carry higher risk of aseptic revision compared with the TT method, while no difference was observed in risk for aseptic reoperation.

Anterior Laxity at 2 Years After Anterior Cruciate Ligament Reconstruction Is Comparable When Using Adjustable-Loop Suspensory Fixation and Interference Screw Fixation

BACKGROUND

Adjustable-loop suspensory fixation (ALSF) devices are commonly used in anterior cruciate ligament reconstruction (ACLR). However, concern exists regarding the potential for lengthening under cyclical loads.

PURPOSE

To compare the residual anterior laxity of 2 methods of femoral fixation, ALSF versus interference screw fixation, in patients undergoing isolated ACLR in the absence of meniscal injuries. To determine the preoperative risk factors associated with residual postoperative anterior laxity.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective analysis was performed comparing 2 groups of patients that underwent primary ACLR using ALSF versus bioabsorbable interference screw fixation. Anterior knee laxity was assessed with Telos stress radiography, while functional outcomes were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS) and Tegner activity level scale at a minimum of 2 years postoperatively. A multivariate analysis was performed to identify factors associated with residual postoperative laxity >3 mm.

RESULTS

Of the 1136 patients who underwent ACLR during the study period, 363 met the inclusion criteria. A total of 272 patients (75%) (mean age, 31.7 ± 10.7 years) with a mean follow-up of 25.7 ± 4.6 months (range, 24-36 months) consented to participate (screw group: n = 121; ALSF group: n = 151). The 2 groups were statistically comparable in terms of age, sex ratio, time from injury to surgery, graft diameter, preoperative laxity, preoperative objective International Knee Documentation Committee (IKDC) grade, and preoperative Tegner score. The mean postoperative laxity as a continuous variable was significantly different comparing the ALSF and screw groups (1.49 ± 1.98 mm and 2.32 ± 1.97 mm, respectively; P < .001). In the screw group, 76 patients (62.8%) had normal (<3 mm), 40 (33.1%) had nearly normal (3-6 mm), and 5 (4.1%) had abnormal (≥6 mm) postoperative knee laxity according to the IKDC grade, while in the ALSF group, 112 patients (74.2%) had normal, 37 (24.5%) had nearly normal, and 2 (1.3%) had abnormal laxity ( P = .0833). No significant difference was found in KOOS or Tegner scores comparing the 2 femoral fixation methods: KOOS, 90.6 ± 7.5 (ALSF group) and 90.6 ± 7.4 (screw group) ( P = .7631), versus Tegner, 6.5 ± 1.3 (ALSF group) and 6.3 ± 1.4 (screw group) ( P = .2992). A negative correlation was found between postoperative laxity and final Tegner ( r_s = -0.303, P < .001) and KOOS scores ( r_s = -0.168, P = .005). The initial univariate analysis showed differences between groups of patients with residual knee laxity ≥3 mm and <3 mm on preoperative pivot shift, preoperative laxity, age, fixation type, and preoperative objective IKDC grade. The multivariate analysis on these factors showed that the pivot shift remained the only significant predictor for residual laxity ≥3 mm for pivot shift grade 2 compared with grade 1 (odds ratio, 4.689 [95% CI, 2.465-9.286]) and for pivot shift grade 3 compared with grade 1 (odds ratio, 58.025 [95% CI, 12.757-557.741]) ( P < .001).

CONCLUSION

For primary ACLR, the use of an ALSF device for femoral fixation is associated with noninferior postoperative anterior knee laxity results compared with interference screw fixation at a minimum 2 years' follow-up. The preoperative pivot shift is the only significant risk factor for postoperative residual anterior knee laxity >3 mm.

Increased incidence of anterior cruciate ligament revision surgery in paediatric verses adult population

PURPOSE

To evaluate the anterior cruciate ligament graft failure rate in a population of 1376 patients submitted to single-bundle anterior cruciate ligament reconstruction procedure. It was hypothesized that the younger the patient, the greater the chance of a new anterior cruciate ligament graft ligament injury.

METHODS

A retrospective chart review was performed on patients who had SB anterior cruciate ligament reconstruction between the years, 2001 and 2016, with a minimum post-operative follow-up period of 6 months. The patient population was divided into three groups, according to age: group 1-under 16 years old; group 2-between 16 and 18 years old; and group 3-older than 18 years old. Data collected included sex, laterality and graft choice data.

RESULTS

In group 1 (under 16 years old), there were 61 primary ACL surgeries performed and 15 (24.6%) revision ACL surgeries. In group 2 (between 16 and 18 years old), there was 57 primary ACL procedures, of which 10 (17.5%) were revisions. In the group 3 (older than 18 years of age), 1258 surgeries were done with 116 (9.2%) revisions.

CONCLUSION

The rate of ACL revision surgery in patients under 16 years of age was significantly higher than that found in patients older than 18 years old. When compared to the population between 16 and 18 years old, there were a higher number of failure cases, however, statistically non-significant.

LEVEL OF EVIDENCE

IV.

Anterolateral rotatory instability in vivo correlates tunnel position after anterior cruciate ligament reconstruction using bone-patellar tendon-bone graft

AIM

To quantitatively assess rotatory and anterior-posterior instability in vivo after anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BTB) autografts, and to clarify the influence of tunnel positions on the knee stability.

METHODS

Single-bundle ACL reconstruction with BTB autograft was performed on 50 patients with a mean age of 28 years using the trans-tibial (TT) (n = 20) and trans-portal (TP) (n = 30) techniques. Femoral and tibial tunnel positions were identified from the high-resolution 3D-CT bone models two weeks after surgery. Anterolateral rotatory translation was examined using a Slocum anterolateral rotatory instability test in open magnetic resonance imaging (MRI) 1.0-1.5 years after surgery, by measuring anterior tibial translation at the medial and lateral compartments on its sagittal images. Anterior-posterior stability was evaluated with a Kneelax3 arthrometer.

RESULTS

A total of 40 patients (80%) were finally followed up. Femoral tunnel positions were shallower (P < 0.01) and higher (P < 0.001), and tibial tunnel positions were more posterior (P < 0.05) in the TT group compared with the TP group. Anterolateral rotatory translations in reconstructed knees were significantly correlated with the shallow femoral tunnel positions (R = 0.42, P < 0.01), and the rotatory translations were greater in the TT group (3.2 ± 1.6 mm) than in the TP group (2.0 ± 1.8 mm) (P < 0.05). Side-to-side differences of Kneelax3 arthrometer were 1.5 ± 1.3 mm in the TT, and 1.7 ± 1.6 mm in the TP group (N.S.). Lysholm scores, KOOS subscales and re-injury rate showed no difference between the two groups.

CONCLUSION

Anterolateral rotatory instability significantly correlated shallow femoral tunnel positions after ACL reconstruction using BTB autografts. Clinical outcomes, rotatory and anterior-posterior stability were overall satisfactory in both techniques, but the TT technique located femoral tunnels in shallower and higher positions, and tibial tunnels in more posterior positions than the TP technique, thus increased the anterolateral rotation. Anatomic ACL reconstruction with BTB autografts may restore knee function and stability.

Revision surgery in anterior cruciate ligament reconstruction: a cohort study of 17,682 patients from the Swedish National Knee Ligament Register

PURPOSE

To investigate the association between surgical variables and the risk of revision surgery after ACL reconstruction in the Swedish National Knee Ligament Register.

METHODS

This cohort study was based on data from the Swedish National Knee Ligament Register. Patients who underwent primary single-bundle ACL reconstruction with hamstring tendon were included. Follow-up started with primary ACL reconstruction and ended with ACL revision surgery or on 31 December, 2014, whichever occurred first. Details on surgical technique were collected using an online questionnaire. All group comparisons were made in relation to an "anatomic" reference group, comprised of essential AARSC items, defined as utilization of accessory medial portal drilling, anatomic tunnel placement, visualization of insertion sites and pertinent landmarks. Study end-point was revision surgery.

RESULTS

A total of 108 surgeons (61.7%) replied to the questionnaire. A total of 17,682 patients were included [n = 10,013 males (56.6%) and 7669 females (43.4%)]. The overall revision rate was 3.1%. Older age as well as cartilage injury evident at index surgery was associated with a decreased risk of revision surgery. The group using transtibial drilling and non-anatomic bone tunnel placement was associated with a lower risk of revision surgery [HR 0.694 (95% CI 0.490-0.984); P = 0.041] compared with the anatomic reference group. The anatomic reference group showed no difference in risk of revision surgery compared with the transtibial drilling groups with partial anatomic [HR 0.759 (95% CI 0.548-1.051), n.s.] and anatomic tunnel placement [HR 0.944 (95% CI 0.718-1.241), n.s.]. The anatomic reference group showed a decreased risk of revision surgery compared with the transportal drilling group with anatomic placement [HR 1.310 (95% CI 1.047-1.640); P = 0.018].

CONCLUSION

Non-anatomic bone tunnel placement via transtibial drilling resulted in the lowest risk of revision surgery after ACL reconstruction. The risk of revision surgery increased when using transportal drilling. Performing anatomic ACL reconstruction utilizing eight selected essential items from the AARSC lowered the risk of revision surgery associated with transportal drilling and anatomic bone tunnel placement. Detailed knowledge of surgical technique using the AARSC predicts the risk of ACL revision surgery.

LEVEL OF EVIDENCE

III.

Management of Anterior Cruciate Ligament Injury: What's In and What's Out?

Sports medicine physicians have a keen clinical and research interest in the anterior cruciate ligament (ACL). The biomechanical, biologic, and clinical data researchers generate, help drive injury management and prevention practices globally. The current concepts in ACL injury and surgery are being shaped by technological advances, expansion in basic science research, resurging interest in ACL preservation, and expanding efforts regarding injury prevention. As new methods are being developed in this field, the primary goal of safely improving patient outcomes will be a unifying principle. With this review, we provide an overview of topics currently in controversy or debate, and we identify paradigm shifts in the understanding, management, and prevention of ACL tears.

Imaging the Anterior and Posterior Cruciate Ligaments

The anterior and posterior cruciate ligaments are important stabilizers of the knee joint function. Although they are both similar in their native appearance, they possess slightly different properties and complement each other's function. The imaging findings differ between the anterior and posterior cruciate ligaments. While MRI is the main imaging modality, radiographs and CT have a role in pre- and post-operative imaging. The aim of this review is to present pre-and post-operative imaging findings of injured cruciate ligaments. A special emphasis will be placed on the potential pitfalls in cruciate ligament imaging.