Summary
We determined whether the early associated use of OKC and closed kinetic chain (CKC) and showed that OKC improved quadriceps and hamstring strength in the early phase of rehabilitation after ACLR and that the early use of OKC did not increase graft laxity at 3 and 6 months postoperatively in hamstring graft patients.
Abstract
Background
Muscle strengthening is a key element of rehabilitation after anterior cruciate ligament reconstruction (ACLR), while concomitantly respecting biological (graft healing), physiological (neuromuscular adaptations), and psychological challenges that the patient must face. Open kinetic chain (OKC) is an effective method to improve muscle function; however, there is controversy with regard to its use in the early phase of rehabilitation after ACLR.
Purpose
Determine whether the early associated use of OKC and closed kinetic chain (CKC) improved quadriceps and hamstring strength in the early phase of rehabilitation after ACLR and whether the early use of OKC had an influence on graft laxity at 3 and 6 months postoperatively in hamstring graft patients.
Study Design: Prospective Controlled cohort study. Level of Evidence II
Methods
This study included two groups: an Intervention group with OKC+CKC exercises (n=51) and a Control group (n = 52) with CKC exercises only.
The intervention group included the OKC protocol for quadriceps and hamstring exercises which was started 4 weeks after ACLR (31.4 days ± 7.6). At 3 months (101.9 days ± 18.4) and 6 postoperative months (199.2 days ± 28.1), an isokinetic test was performed to calculate peak torque-to-body weight ratio (PT/BW) for the quadriceps and hamstrings and then Limb Symmetry Index (LSI = PT/BW(operated)/ PT/BW(non-operated) x100). Anterior knee laxity was measured by comparative measurements performed by GNRB.
Results
At 3 and 6 postoperative months, quadriceps strength in the Intervention group was higher than in Control group for LSI (76.1 % ± 0.21 vs 46.9 % ± 0.21, p < 0.001 and 91 % ± 0.17 vs 61.8 % ± 0.26, p < 0.001, respectively) and PT/BW (1.81 Nm.kg-1 ± 0.75 vs 0.85 Nm.kg-1 ± 0.50, p < 0.001 and 2.40 Nm.kg-1 ± 0.73 vs 1.39 Nm.kg-1 ± 0.70, p < 0.001, respectively). There were similar findings for the hamstring strength: LSI (86.1 % ± 0.21 vs 64.3 % ± 0.24, p < 0.001 and 91.9 % ± 0.17 vs 82.4 % ± 0.24, p < 0.001, respectively) and PT/BW (1.09 Nm.kg-1 ± 0.36 vs 0.69 Nm.kg-1 ± 0.39, p < 0.001 and 1.41 Nm.kg-1 ± 0.41 vs 1.06 Nm.kg-1 ± 0.39, p < 0.001, respectively). At 3 months no difference was observed for laxity between Intervention and Control groups (p = 0.48). At 6 months the laxity was also similar in both groups (p = 0.31).
Conclusion
These results indicate that early use of the OKC protocol for both quadriceps and hamstring exercises, in addition to conventional CKC exercises, results in better correction of quadriceps and hamstring strength deficits without increasing graft laxity.