Autologous chondrocyte implantation versus microfracture for knee cartilage injury: a prospective randomized trial, with 2-year follow-up.

The objective was to evaluate the functional performance over a 2-year period following autologous chondrocyte implantation (ACI) in an open knee procedure compared to microfracture. Objective functional outcome was studied as secondary analysis in a subgroup of patients, in a randomized clinical trial, with concealed allocation and independent evaluators. Sixty-seven patients with local cartilage defect, with a mean size of 2.4 cm(2) (SD 1.5) of the femoral condyle of the knee were included. Thirty-three patients underwent the microfracture and 34 the ACI procedure. An identical rehabilitation protocol was implemented for both groups. Active knee flexion and extension range, anterior laxity, knee extension strength (concentric at 60 degrees/s) and single leg hop performance (single hop, crossover triple hop and 6 m timed hop test) were evaluated pre-surgery and at 6, 9,12 and 24 months post-surgery. We calculated the symmetry index for individual and four performance tests pooled. Mixed linear model analyses were used with confidence interval set at 95%. The change over 2 years for the pooled performance-based tests was comparable between the two treatment arms. At 2 years, 70% (38/54) of all patients returned to >85% symmetry in overall functional performance. A decrease in functional performance at 6 months following ACI resulted in slower recovery at 9 and 12 months compared to microfracture. Rehabilitation following both cartilage repair procedures is a lengthy process. At 2 years after surgery, ACI patients have similar overall functional outcome compared to microfracture patients.

Physical activity levels after characterized chondrocyte implantation versus microfracture in the knee and the relationship to objective functional outcome with 2-year follow-up.

BACKGROUND: Characterized chondrocyte implantation results in superior structural repair compared with microfracture, but may be associated with a slower recovery of physical activity levels due to the arthrotomy. HYPOTHESES: Our hypotheses were that (1) microfracture results in increased activity levels over 2 years after surgery compared with characterized chondrocyte implantation, (2) patients with high preinjury activity levels have a better functional outcome, and (3) high levels of low-load activities after surgery improve functional outcome. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Sixty-seven patients with local cartilage defects (mean size, 2.4 cm(2); standard deviation, 1.5 cm(2)) of the femoral condyle underwent characterized chondrocyte implantation (n = 33) or microfracture (n = 34), followed by an identical rehabilitation protocol. Activity levels (assessed using the Activity Rating Scale) and functional outcome were determined at baseline, and 1 and 2 years after surgery. Functional outcome was based on the pooled symmetry index (derived from isokinetic knee extension strength and 3 one-legged hop tests). Patients' participation in low-load activities during the first 3 months after surgery was assessed using rehabilitation data. Mixed linear model analyses and Wilcoxon rank sum tests were used. RESULTS: Activity levels in patients treated with characterized chondrocyte implantation and microfracture were comparable at 1 and 2 years after surgery. Preinjury activity levels showed no relationship to functional outcome. Lack of postoperative low-load activities resulted in a significantly worse functional outcome (mean pooled symmetry index 78.2%) compared with high levels of postoperative surgery low-load activities (mean pooled symmetry index 92.4%). CONCLUSION: Despite differences between the characterized chondrocyte implantation and microfracture procedures, patients' activity levels were comparable at 2 years after surgery. Lack of low-load activities after surgery adversely affected functional outcome.

Functional assessment and muscle strength before and after reconstruction of chronic anterior cruciate ligament lesions.

PURPOSE: The goal of this study was to evaluate strength and functional capacity before and after anterior cruciate ligament (ACL) reconstruction to determine the influences of preoperative strength deficit, graft type, and gender, as well as their clinical relevance in predicting postsurgical recovery and determining the postoperative rehabilitation program. METHODS: This was a retrospective review of prospectively collected uniform data from a group of 191 patients undergoing ACL reconstruction. We assessed functional capabilities and strength of the quadriceps and hamstring at 60 degrees/s and 180 degrees/s by use of a Cybex II dynamometer (Lumex, Ronkonkoma, NY) before and 6, 9, and 12 months after surgery. RESULTS: There was a preoperative quadriceps strength deficit and a decreased limb symmetry index in patients with an ACL deficiency. This strength deficit increased postoperatively, with the highest measured deficit occurring at 6 months postoperatively and a clear improvement from 6 to 12 months. Functional assessment showed identical development. There was a statistically significant relation between an increased quadriceps strength deficit preoperatively and poor early postoperative functional performance. For the bone-patellar tendon-bone (BPTB) group, there was an increased quadriceps strength deficit compared with the semitendinosus and gracilis tendon (STG) group, and the STG group had an increased hamstring strength deficit on postoperative testing. The postoperative hamstring strength deficit is significantly increased in female patients. CONCLUSIONS: All of these data suggest that quadriceps strength deficit is related to the ACL injury and is increased by ACL reconstruction. Even 1 year after ACL reconstruction, a quadriceps strength deficit of almost 20% persists. Flexion strength is within the normal range before and after surgery. These results are influenced by graft choice, with a higher quadriceps strength deficit for BPTB grafts. STG grafts induce a higher hamstring strength deficit compared with BPTB grafts. Functional assessment is improved at 9 and 12 months postoperatively compared with preoperatively regardless of graft type. However, an increased preoperative quadriceps strength deficit results in a lower limb symmetry index at 6 and 9 months postoperatively. LEVEL OF EVIDENCE: Level IV, therapeutic case series.