Abstract
Objectives:
Perioperative rehabilitation is critical to restoring function and preventing reinjury in ACLR patients. Single-leg hop and isokinetic strength testing are commonly utilized by clinicians to assess patient progress. The impact of early stage progress on later stage outcomes is, however, not well understood. This study aimed to identify the effects of early postoperative isokinetic quadriceps strength and single-leg hop performance on functional recovery after primary ACLR, to determine the manner in which changes in these parameters during perioperative rehabilitation relate to fast and successful functional recovery.
Methods:
Patients having a primary ACLR were consented into a long-term study and were retrospectively reviewed with the following inclusion criteria: ACLR using a contralateral patellar tendon graft with normal extension ROM and stability at 2 months postoperative, per the International Knee Documentation Committee (IKDC) objective form. Patients were excluded with a preoperative modified Tegner level <7. Predictor variables included 180°/second isokinetic quadriceps strength test (preoperative, 2 months, 4 months) and single leg hop for distance (preoperative and 4 months). Strength was assessed using limb symmetry index (LSI) with the ACLR knee strength being divided by the graft donor knee strength, percent of preoperative normal, and percent change over time at each interval, while hop testing was normalized to height. Outcome variables assessed were return to sport (RTS) time in months, return to preoperative modified Tegner level in the first 12 months after surgery (yes/no), and Cincinnati Knee Rating System (CKRS) at 12 months postoperative. Stepwise multiple regression analysis was used to predict RTS time, return to preoperative modified Tegner level, and CKRS based on demographics and objective measures.
Results:
A total of 1093 patients were eligible for analysis and 607 were used for the RTS model, 724 for the return to preinjury Tegner level model, and 705 for the CKRS model. Mean age for the cohort was 19.6 ± 5.5 years (range, 11.9-39.7) and 52.1% were male. In the model predicting RTS time, the following variables reduced RTS time: female sex, younger age, higher preoperative LSI, higher ACLR knee strength gains from preoperative to 2 month, and higher normalized single leg hop distance. In the model predicting a return to preoperative Tegner level, the following variables increased the likelihood: younger age, lower preoperative Tegner level, lower strength deficits with LSI at 2 months, and higher normalized single leg hop distance. In the model predicting CKRS scores, the following variables increased the score: younger age and higher normalized single leg hop distance. Model statistics can be seen in Table 1.
Conclusions:
The study found several early rehabilitation performance measures significantly influenced key outcomes. Perioperative rehabilitation should promote early relative gains in quadriceps strength for the ACLR knee, maintaining limb symmTaetry, and maximizing single leg hop distance to encourage faster RTS, higher subjective scores, and improve the likelihood of patients returning to preoperative activity levels. By quantifying the importance and predictiveness of these rehabilitation performance metrics, clinicians may improve their protocols to promote superior outcomes following ACLR.
