Rehabilitation after anterior cruciate ligament reconstruction using patellar tendon or hamstring grafts : open and closed kinetic chain exercises

Abstract

Aim: The overall aim of this thesis was to improve the knowledge of appropriate exercises, the influence of preoperative factors for good clinical outcome as well as the patient s experience of the rehabilitation after anterior cruciate ligament (ACL) reconstruction with patellar tendon or hamstring graft.

Methods: The strain in the anteromedial bundle of the ACL was measured with the strain gauge technique in nine patients scheduled for meniscectomy. The measurement was performed during a step-up, a step-down, a lunge and a one-leg sit to stand exercise (Study I). Sixty-eight patients, 36 males and 32 females, with either patellar tendon graft (34 patients) or hamstring graft (34 patients) were randomly allocated to either early (4 th postoperative week) or late start (12 th postoperative week) of open kinetic chain (OKC) quadriceps exercises. The four groups consisted of patellar tendon reconstruction, early start (P4) or late start (P12), hamstring tendon reconstruction, early start (H4) or late start (H12). Range of motion, anterior knee laxity, pivot shift, postural sway, thigh muscle torques and anterior knee pain were evaluated prior to surgery and 3, 5 and 7 months after surgery (Study II). The variables investigated in Study II, and demographic data were calculated in a multiple regression model to find the strongest predictors of the 12 months outcome, measured with two subgroups of KOOS (Function in sport and recreation; Quality of life), one-leg hop test, and Tegner Activity Scale (Study III). Ten patients were interviewed focusing on expectations and challenges from injury to one year after ACL reconstruction. The transcribed interviews were analyzed using a qualitative thematic content interpreted analysis (Study IV).

Results: No significant differences in ACL strain were shown between exercises. There was a significant increase in ACL strain towards extension in all studied exercises (Study I).

No significant group differences were found in range of motion, postural sway and anterior knee pain 3, 5 and 7 months, postoperatively. The H4 group showed a higher mean difference of laxity over time of 1.0 mm than the P4 group (p=0.04) and 1.2 mm than the H12 group (p=0.01). All groups, except for the P4 group reached preoperative values of quadriceps torques, while the H4 and the H12 groups showed significantly lower hamstring torques at the 7 months follow-up compared with preoperatively (Study II). Step-wise regression showed that absence/less preoperative AKP and low knee influence on pre-operative activity level explained 31 % in Sport/Rec KOOS outcome. Additionally, high scores on the AKP score predicted the outcome alone to 14 % in QOL KOOS. Absence of or minor AKP was the strongest predictor for Sport/Rec KOOS and QOL KOOS. Patellar tendon graft in favor of hamstring tendon graft and a short time (< 6 months) between injury and ACL surgery partly explained a higher level of activity (TAS). Absence of cartilage damage explained 6 % of good outcome as measured with the one-leg hop test (Study III).

The participants perceived no real choice between operative and non-operative treatment. Only surgery symbolized a full return to the pre-injury level of sport activity, and surgery was understood as the only way to become a completely restored functional human being . A major source of frustration was that the meaning of and progress during the rehabilitation did not match their expectations. Three different responses to the challenge of a prolonged rehabilitation were expressed: going for it , being ambivalent , and giving in . Fear of re-injury was common; however some participants decided not to return to their pre-injury level of sporting activity due to other reasons than physical limitations or fear of re-injury (Study IV).

Conclusion: The studied exercises did not produce greater strain on the ACL than the traditional two-legged squat. Early start of OKC quadriceps exercises leads to greater anterior knee laxity than late start after hamstring ACL reconstruction as well as after patellar tendon ACL reconstruction. No group differences in postural sway and AKP were found.

The evaluated preoperative variables could partly predict clinical outcomes. Absence of or minor AKP before surgery was the strongest predictor for the outcome 12 months after ACL reconstruction. Preoperative information in terms of the meaning and extent of rehabilitation would have been helpful as well as guidance in realistic goal-setting and coaching throughout the entire rehabilitation process.