Gender comparison of knee strength recovery following ACL reconstruction with contralateral patellar tendon graft.

While gender appears to play a role in the incidence of Anterior Cruciate Ligament (ACL) injury, it is unclear if a gender bias in recovery following reconstruction exists. The goal of this investigation was to compare knee strength across gender from pre-operation through six months of rehabilitation following an acute rupture with no associated injuries compromising recovery. All operations were performed by the same surgeon (co-author: RVT) between 1996 and 2002 using the middle 10 mm of the contralateral patellar tendon as the replacement graft. Of the 1,175 ACL patients seen by this surgeon, 102 (57 women and 45 men) fit the inclusion criterion which also required patients to have made every visit (pre-op, 5 wks, 10 wks, 4 months, and 6 months post-op) and completed every test (isokinetic knee flexion and extension at 180 degrees/s as well as isometric leg press). All patients were on the same rehabilitation program allowing for individualized advancement. Strength values were normalized to the uninvolved knee prior to surgery with a flexor/extensor ratio computed from isokinetic strength. There was a significant change (p < 0.05) in each parameter for both sides across time (p < = 0.003) except for the flexor/extensor strength ratio in the men on their involved side (p = 0.119). The only significant differences (p < 0.05) between gender at any time points were in the involved side flexor strength at 5 weeks (p = 0.029), 10 weeks (p = 0.013), and 4 months (p = 0.021) where the men were stronger. In conclusion, since recovery of strength following surgery is not identical between men and women, gender specific rehabilitation protocols may be warranted.