Pre-injury Sports Activity Level Affects Knee Strength Recovery After Acl Reconstruction

Abstract

PURPOSE: The aim of this study was to investigate the effects of pre-injury sports acitivity level on knee strength recovery after anterior cruciate ligament (ACL) reconstruction. METHODS: Fifty five male ACL reconstructed patients who injuried their knee during sports were included in this study. The patients were divided into two groups by using sports activity rating scale (SARS). The patients whose pre-injury SARS score was ≥ 75 referred as Group1 and whose pre-injury SARS score was < 75 referred as Group 2. Isometric strength of quadriceps and hamstring muscles were measured at 4th, 12th and 24th weeks after surgery. Strength changes from 4 weeks to 12 weeks (early period) and from 12 weeks to 24 weeks (late period) were defined as strength recovery. Repeated measures of ANOVA with one within factor (time), one between factor (group) and three covariates (age, body mass index and time to surgery) was used for statistical analysis. RESULTS: There was a significant interaction between groups and quadriceps strength recovery (F(1,50)= 8.5, p=0.008). Quadriceps recovery in Group1 was greater than Group2 in early period (p=0.04). Although quadriceps strength was greater in Group1 at 12th and 24th weeks (Table 1), quadriceps recovery in late period was not different between groups (p=0.11). There was no significant interaction between groups and hamstring strength recovery (F(1,50)= 1.73, p=0.20). Age, body mass index and time to sugery had no effect on quadriceps and hamstring strength recovery (p>0.05). CONCLUSION: Higher sports activity level before ACL injury enhance quadriceps recovery only in the early period after surgery.On the other hand, hamstring strength recovery in early and late period is not affected by pre-injury sports activity level.Table 1: Quadriceps and hamstring strength outcomes at 4th,12th and 24th weeks after surgery.