RISK FACTORS FOR FAILURE FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION IN A PEDIATRIC POPULATION: A NOVEL PREDICTION ALGORITHM

Background: Pediatric anterior cruciate ligament (ACL) reconstruction is becoming increasingly common, however, there is limited literature on the risk factors for failure in this demographic. Hypothesis/Purpose: In the present study we sought to: 1. To determine the rate of pediatric ACL reconstruction (ACLR) failure requiring revision surgery in a nationally representative sample. 2. To determine the associated patient/injury-specific risk factors for ACLR failure. 3. To examine the differences in the rate and risks of failure between pediatric and adult patients. Methods: Patient records were drawn from Humana individual health plans and Medicare medical records. Adult and pediatric patients who underwent primary ACLR and subsequent reoperation for either ACL revision surgery or a revision meniscal procedure between 2011-2016 were identified. Multivariate regression was used to determine the significant risk factors for ACL revision and overall reoperation rates in pediatric and adult patients. A risk algorithm was developed to predict the risk of ACL revision following pediatric ACL reconstruction. Results: Pediatric patients were significantly more likely to require ACL revision within one year (OR=1.97, 95%CI 1.57-2.45, p<0.0001) and five years (OR=3.22, 95%CI 2.77-3.72, p<0.0001) following their index ACLR compared to adults. Survivorship of the index ACL procedure was significantly decreased in pediatric patients (log-rank test p<0.0001) (Figure 1). Pediatric patients were also at higher risk of sustaining a contralateral ACL tear compared to adults (5.9% vs. 1.4%, respectively, p<0.0001). Meniscus injury was a risk factor for overall re-operation (OR=2.18, 95%CI 1.67-2.89 p<0.0001) as well as ACL revision (OR=2.28, 95%CI=1.66-3.21, p<0.0001) in the pediatric cohort. This increased risk was sustained despite the type of meniscal tear intervention, with patients undergoing concurrent meniscal repair (OR=1.84, 95%CI 1.43-2.38, p<0.0001) or meniscectomy (OR=2.20, 95%CI 1.72-2.82, p<0.0001) having a higher likelihood of requiring a revision ACLR. Concomitant MCL injury but not LCL injury was a risk factor for ACL revision in this cohort (OR=1.70, 95%CI 1.31-2.19, p<0.0001). Male sex and (OR=0.78, 95%CI 0.63-0.96, p=0.0204) and being >14 years old (OR=0.62, 95%CI 0.45-0.86, p=0.0035) was associated with a decreased risk of overall reoperation. The risk algorithm demonstrated the highest probability for ACLR failure in females, less than 15 years of age, with concomitant meniscus and MCL injury, demonstrating a 36% risk of failure (Table 1). Conclusion: Compared to adults, pediatric patients have an increased likelihood of ACL revision surgery, contralateral ACL tears, and meniscal reoperation within 5 years of an index ACLR. [Table: see text][Figure: see text]

Effect of Early Residual Laxity After Anterior Cruciate Ligament Reconstruction on Long-term Laxity, Graft Failure, Return to Sports, and Subjective Outcome at 25 Years

Background: In spite of supposedly successful surgery, slight residual knee laxity may be found at follow-up evaluations after anterior cruciate ligament reconstruction (ACLR), and its clinical effect is undetermined. Purpose: To investigate whether a 3- to 5-mm increase in anterior translation 6 months after ACLR affects the risk of graft failure, rate of return to sports, and long-term outcome. Study Design: Cohort study; Level of evidence, 2. Methods: From a cohort of 234 soccer, team handball, and basketball players undergoing ACLR using bone–patellar tendon–bone graft, 151 athletes were included who attended 6-month follow-up that included KT-1000 arthrometer measures. A tight graft was defined as <3-mm side-to-side difference between knees (n = 129), a slightly loose graft as 3 to 5 mm (n = 20), and a loose graft as >5 mm (n = 2). Graft failure was defined as ACL revision surgery, >5-mm side-to-side difference, or anterolateral rotational instability 2+ or 3+ at 2-year follow-up. Finally, a 25-year evaluation was performed, including a clinical examination and questionnaires. Results: The rate of return to pivoting sports was 74% among athletes with tight grafts and 70% among those with slightly loose grafts. Also, return to preinjury level of sports was similar between those with slightly loose and tight grafts (40% vs 48%, respectively), but median duration of the sports career was longer among patients with tight grafts: 6 years (range, 1-25 years) vs 2 years (range, 1-15 years) ( P = .01). Five slightly loose grafts (28%) and 6 tight grafts (5%) were classified as failures after 2 years ( P = .002). Thirty percent (n = 6) of patients with slightly loose grafts and 6% (n = 8) with tight grafts had undergone revision ( P = .004) by follow-up (25 years, range, 22-30 years). Anterior translation was still increased among the slightly loose grafts as compared with tight grafts at long-term follow-up ( P < .05). In patients with tight grafts, 94% had a Lysholm score ≥84 after 24 months and 58% after 25 years, as opposed to 78% ( P = .02) and 33% ( P = .048), respectively, among patients with slightly loose grafts. Conclusion: A slightly loose graft at 6 months after ACLR increased the risk of later ACL revision surgery and/or graft failure, reduced the length of the athlete’s sports career, caused permanent increased anterior laxity, and led to an inferior Lysholm score.

Revision Single-Stage Anterior Cruciate Ligament Reconstruction Using an Anterolateral Tibial Tunnel

Revision anterior cruciate ligament (ACL) reconstruction is a technically demanding enterprise. Management of widened or previously malpositioned tunnels is challenging and often requires innovative approaches. The purpose of this study was to evaluate the function and clinical results of revision single-stage ACL surgery using an anterolateral tibial tunnel (ALTT). A consecutive series of knees with arthroscopic ACL revision surgery were analyzed prospectively between April 2012 and September 2015. Among the 93 patients presented with revision ACL reconstruction, 25 patients met the study inclusion criteria for the ALTT technique and were followed up for a minimum of 2 years (range: 24–51 months). The clinical results were evaluated by means of the Lysholm score, International Knee Documentation Committee (IKDC) score, and Tegner activity level scale, and the knee stability was assessed by the Lachman test, pivot shift test, and anterior drawer test. Magnetic resonance imaging (MRI) of the index knee before the surgery and 2 years after revision surgery was assessed. The mean IKDC subjective score, mean Tegner activity level scale, and mean Lysholm score significantly improved in all study participants. This study showed that ACL revision surgery with ALTT can reliably restore stability and provide fair functional outcomes in patients with ACL retear. One could expect acceptable lateral tibial tunnel length compared with medial tibial tunnel in classic ACL revision, intact bony surround, and good graft fixation. This technique is clinically relevant in that making an anterolateral tunnel in one-stage ACL revision surgery had a good subjective result with low complication rate in midterm follow-up.