Knee flexor strength after ACL reconstruction: comparison between hamstring autograft, tibialis anterior allograft, and non-injured controls.

Hamstring muscle group dysfunction following anterior cruciate ligament reconstruction (ACL) using a semitendinosus-gracilis autograft is a growing concern. This study compared the mean peak isometric knee flexor torque of the following three groups: subjects 2 years following ACL reconstruction using semitendinosus-gracilis autografts (Group 1), subjects 2 years following ACL reconstruction using tibialis anterior allografts (Group 2), and a non-injured, activity-level-matched control group (Group 3). We hypothesized that Group 1 would have greater mean involved lower extremity peak isometric knee flexor torque deficits than the other groups. Handheld dynamometry with subjects in prone and the test knee at 90 degrees flexion was used to determine bilateral peak isometric knee flexor torque. Group 1 (86.4 +/- 11) and Group 2 (80.5 +/- 13) had similar 2000 IKDC Subjective Knee Evaluation Form scores (P = NS). Group 1 had a mean involved lower extremity peak isometric knee flexor torque deficit of -17.0 +/- 14 Nm. Group 2 had a mean involved lower extremity peak isometric knee flexor torque deficit of -0.8 +/- 9 Nm. Group 3 (control) had a mean left and right lower extremity peak isometric knee flexor torque difference of -0.7 +/- 14 Nm. Group 1 had decreased involved lower extremity peak isometric knee flexor torque compared to Groups 2 and 3 (two-way ANOVA; group x side interaction P < 0.05, Tukey HSD = 0.008). Long-term knee flexor strength deficits exist following hamstring autograft use for ACL reconstruction that does not occur when a tibialis anterior allograft is used. Early identification of impaired knee flexor strength among this group and modified rehabilitation may reduce these deficits. Adding quantitative biomechanical testing of sprinting and sudden directional change movements to the standard physical therapy evaluation will better elucidate the clinical and functional significance of the observed knee flexor strength impairments and aid in determining sport specific activity training readiness.

Correlation of spinal canal dimensions to efficacy of epidural steroid injection in spinal stenosis.

PURPOSE: To determine a critical canal dimension in patients with spinal stenosis that predicts response to epidural steroid injections (ESI). METHODS: Lumbar spinal stenosis patients with a computed tomography scan before ESI were identified through ICD-9/CPT codes. Using a digital caliper, canal dimensions on axial cuts of each lumbar intervertebral level were recorded: the transverse canal diameter in line with the facets including the soft tissues, TC; the transverse osseous canal diameter, OS; and the mid-sagittal anteroposterior diameter, MS. Minimum and maximum measurements were determined. Patients who improved after ESI and those that required a decompression after ESI were differentiated. RESULTS: Eighty-four patients were included in the study. Fifty required surgical decompression after ESI and 34 patients improved after ESI. There were no statistically significant differences in the demographics between the 2 groups. Mean minimum dimensions in the surgical group were 9.47 mm (TC), 16.53 mm (OS), and 12.40 mm (MS); and 9.75 mm (TC), 16.65 mm (OS), and 12.39 mm (MS) in the nonsurgical group. Mean ratio between the maximum and minimum dimensions in the surgical group was 1.76 (TC), 1.35 (OS), and 1.57 (MS); and 1.86 (TC), 1.47 (OS), and 1.63 (MS) in the nonsurgical group. There was no statistically significant difference in the minimum measurement in any dimension between the surgical and the nonsurgical group. There was also no statistically significant difference in the ratio between the minimum and maximum measurement in any dimension between the surgical and the nonsurgical group. CONCLUSIONS: Spinal canal dimension is not predictive of success or failure of ESI in patients with spinal stenosis.

Knee flexor function 2 years after anterior cruciate ligament reconstruction with semitendinosus-gracilis autografts.

PURPOSE: This retrospective study evaluated the knee flexor function of 20 patients at 25.8 +/- 5 months after anterior cruciate ligament reconstruction with use of a semitendinosus-gracilis (STG) autograft. METHODS: Clinical examinations included instrumented isometric testing, conventional and prone isokinetic testing, hop testing, knee arthrometry, modified visual analog scale leg sensation evaluation, and International Knee Documentation Committee (IKDC) Subjective Knee and Current Health Evaluations. Paired t tests were used to evaluate side-to-side differences, and multiple regression analysis related these findings to knee function (P < .05). RESULTS: Involved side active knee flexion was decreased by 8.2 degrees +/- 5 degrees. Involved side isokinetic knee flexor work was decreased by 76.7 +/- 118 J at 60 degrees/sec during conventional testing and was decreased by 94.4 +/- 107 J and 86.3 +/- 115 J at 60 degrees/sec and 180 degrees/sec, respectively, during prone testing. Isometric testing at 90 degrees and 120 degrees flexion in internal and neutral tibial rotation, respectively, revealed decreased involved side knee flexor torque > or = 13.2 +/- 12 Nm. Sensation scores revealed a mean 24% difference from the uninvolved side (range, 0% to 80%). Multiple regression revealed that instrumented isometric testing at 90 degrees knee flexion with neutral tibial rotation and the role physical score predicted 62% (R2 = .62) of involved side forward hop capability (P < .0001). Self-reported activity level and isokinetic work (60 degrees/sec) predicted 69% (R2 = .69) of involved side lateral hop capability (P < .0001). Sensation, role physical score, and prone isokinetic peak torque (180 degrees/sec) predicted 80% (R2 = .80) of involved side medial hop capability (P < .0001). CONCLUSIONS: Two years after surgery, functionally significant knee flexor strength deficits remain. Prone isokinetic knee flexor work at 60 degrees /sec, isometric knee flexor torque at 90 degrees flexion-neutral tibial rotation, and sensation score were related to patient function 2 years after anterior cruciate ligament reconstruction with an STG autograft. LEVEL OF EVIDENCE: Level IV, therapeutic case series.