RECOVERY OF LOWER EXTREMITY STRENGTH AND FUNCTION FOLLOWING ACL RECONSTRUCTION IN SKELETALLY IMMATURE PATIENTS

Abstract

BACKGROUND: Following anterior cruciate ligament reconstruction (ACLR) surgery, lower extremity recovery of the uninjured limb >90% is commonly recommended for clearance to return-to-play (RTP). However, evidence regarding the timing of achieving such a recovery is lacking, especially in skeletally immature populations. Therefore, the purpose of this study was to examine the proportion of pediatric ACLR patients (<15 years) who achieve >90% of lower extremity recovery at 6-9 months following ACLR surgery. METHODS: Retrospective case series study design was employed. Following inclusion criteria were used: 1) those who had ACLR surgery, 2) their chronological ages were under 15 years, and 3) growth plates remains open. Status of physis (growth plates) was examined through radiographs and MRI images by orhtopaedic physicians. ACLR patients who had previous ACL surgery in either ipsilateral or contralateral limb were excluded. During RTP tests, bilateral strength (quadriceps, hamstrings, hip abductor, and hip extensor), Y-balance (anterior, posteromedial, and posterolateral reach), and hop (single, triple, cross-over, and 6 meter timed) tests were assessed. Main outcome variables were number of skeletally immature ACLR patients whose limb symmetry index (LSI) were >90% during RTP tests. Descriptive statistics were used to analyze frequency, mean, standard deviation, and percentages (%). RESULTS: A total of 106 skeletally immature ACLR patients were enrolled (Table 1). Hamstrings and iliotibial band grafts were commonly used for ACLR surgery (Table 2). Mean time from ACLR to RTP testing was 6.8±3.4 months (Table 2). The proportion of skeletally immature ACLR patients, overall, achieving >90% of LSI in strength was: 74.5% in quadriceps, 39.0% in hamstrings, 81.0% in hip abductors, and 82.9% in hip extensors. Y-balance test results indicated 79.5% in anterior reach, 84.8% in posteromedial reach, and 86.7% in posterolateral reach. Hop test showed 65.3% in single hop, 69.1% in triple hops, 59.1% in cross-over hops, and 74.2% in 6 meter timed hops. Proportion of skeletally immature ACLR patients who passed all four strength, three Y-balance, and four hop tests were 19.8%, 64.8%, and 27.8%. Only 4.2% of skeletally immature ACLR patients demonstrated >90% of LSI in all tests at RTP tests. CONCLUSION/SIGNIFICANCE: Approximately 7 months following ACLR, approximately 3/4 of the patients achieved >90% of quadriceps, hip abductor, and hip extensor strength, but not hamstrings strength. While over 4/5 of the patients performed >90% in Y-balance, less than 3/4 achieve >90% on hop tests. These results suggest approximately 7 months following ACLR may be too early for returning competitive sports in skeletally immature population. Future studies are warranted to find an association between those RTP test batteries and subsequent ACL tear risks. [Table: see text][Table: see text]