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1996 Publications

Pre-Op ROM and Strength as Predictors of 6-Month Post-Op Measures of Knee Function Following ACL Reconstructionby Tyler TF, McHugh MP, Hershman EB, Gleim GW, Nicholas SJNISMAT, Lenox Hill Hospital, NY NY - last modified 2013-02-09 00:00
Journal of Orthopedic and Sports Physical Therapy 23(1), 1996.


Pre-operative screening of patients undergoing anterior cruciate ligament (ACL) reconstruction is thought to be important in predicting surgical outcome. The purpose of this study was to determine the effect of pre-operative (pre-op) knee range of motion (ROM) and strength on ROM and strength 6 months postoperatively (post-op).

Approximately one week prior to ACL reconstruction 72 patients (43 male, 29 female) were tested for isokinetic knee flexion and extension strength, goniometric knee flexion and extension ROM, and Lysholm questionnaire. Tests were repeated 6 months post-op. All patients participated in an accelerated rehabilitation program.

Pre-op knee extension ROM (KE ROM) was significantly correlated with KE ROM 6 months post-op. Patients with full extension pre-op (equal to contralateral knee) had a 1.1 +/- 0.6 deg. difference 6 months post-op; patients lacking 1-4 deg. ROM pre-op had a 4.7 +/- 1 deg. difference 6 months post-op; patients lacking >= 5 deg. ROM pre-op had a 4.0 +/- 0.9 difference 6 months post-op (ANOVA p < 0.01).

Lack of knee flexion ROM preoperatively did not affect flexion ROM 6 months post-op. Pre-op knee extension strength (KE strength) was not significantly correlated with KE strength 6 months post-op (r=0.2, p=0.08). Patients with pre-op KE weakness (< 30% deficit) had a 31 +/- 2% deficit 6 months post-op; patients with severe pre-op KE weakness (> 30% deficit) had a 42 +/- 3% deficit 6 months post-op (p < 0.01).

Pre-op knee flexion strength did not affect knee flexion strength 6 months post-op. Pre-op KE ROM and KE strength did not influence Lysholm scores 6 months post-op. The mean Lysholm scores for each Pre-op ROM and strength group was 85 out of a possible 100, 6 months Post-op.

These results demonstrate the following: 1) A slight loss of knee extension (1-4 deg.) preoperatively can result in difficulty regaining extension postoperatively. 2) The Lysholm score is insensitive to Pre-op knee strength and ROM measures. 3) Gross weakness (> 30%) pre-op was predictive of gross KE deficit post-op.

Therefore, careful assessment of Pre-op knee extension ROM and strength may aid in predicting Post-op results.