The Effect of Knee Bracing After Anterior Cruciate Ligament Reconstruction: A Prospective, Randomized Study With Two Years' Follow-Up.

Risberg MA, Holm I, Steen H, et al (Surgical Clinic, Ullevaal Hospital, University of Oslo; Norwegian Centre for Physiotherapy Research, Oslo; Biomechanics Laboratory, National Hospital Orthopaedic Center, University of Oslo; Radiological Department, National Hospital, University of Oslo; Martina Hansens Hospital, Baerum, Norway), Am J Sports Med. 1999;27:76-83.

The purpose of this single-blinded, prospective study was to identify whether placing a knee in a brace after anterior cruciate ligament (ACL) reconstruction changes knee joint laxity, affects lower-limb function (ie, range of motion [ROM], thigh strength, functional knee tests, patient perception of pain and overall function, total score on Cincinnati knee questionnaire), alters the cross-sectional area of the thigh, and minimizes the risk for meniscal and cartilage injury. The authors cited an extensive literature review regarding the use and benefit of bracing for patients with an ACL-deficient knee as well as postoperatively for patients who underwent ACL reconstruction.

Sixty subjects (28 women and 32 men) with a mean age of 28 years (range = 15-47 years) participated in this study. All subjects had an ACL injury and were suitable candidates for reconstructive surgery. Subjects were randomly enrolled into the brace group (n = 30) or the non-brace group (n = 30). Demographic data were provided including age, acuity versus chronicity of ACL injury, and whether the ACL was an isolated or a combined injury (ie, involvement of meniscal and medial collateral ligaments). Subjects in the brace group wore a DonJoy rehabilitative range of motion brace for 2 weeks and progressed to a DonJoy GoldPoint functional knee brace for the next 10 weeks (total of 3 months). After 3 months, the brace was worn during strenuous activities only. Subjects in the non-brace group did not use any orthotic device postoperatively for the 2 years of this study. Patient adherence was measured using a questionnaire.

All subjects underwent the same postoperative rehabilitation course. The dependent variables (ie, KT-1000 arthrometry, the Cincinnati knee score, range of motion, muscle strength, 3 functional knee tests, thigh atrophy, pain rating) were assessed preoperatively. Follow-up ROM evaluation occurred at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperatively. Cincinnati knee and a KT-1000 evaluation were obtained at all of the above times except at 6 weeks. The researchers used magnetic resonance imaging (MRI) to determine the cross-sectional area of the quadriceps femoris and hamstring muscles and total thigh girth at 3 and 6 months after the operation. Cybex 6000 isokinetic testing at 60 [degrees] /s and 240 [degrees] /s and functional knee testing (stair "hopple," triple jump, and single-legged hop) was completed at 6 months and at 1 and 2 years. At all 5 ROM evaluation times, a 100-mm visual analog scale was used to measure the subject's satisfaction and his or her perception of pain at rest and during activities. All follow-up measurements were performed by the same investigator who performed the preoperative measurements to eliminate inter-observer variability. This investigator was also unaware of group assignments.

The results demonstrated no significant differences between the groups preoperatively as determined by an ANCOVA for age, sex, activity level, acute or chronic ACL injury, or any of the dependent variables measured. Repeated measures ANOVAs and Tukey post hoc testing revealed the following significant differences between the braced and non-braced groups: improvement in the scores on the Cincinnati knee questionnaire and a decrease in hamstring muscle size for the braced group at 3 months after the operation. No differences were seen between the 2 groups at any of the follow-up times for the other dependent variables, including joint laxity, isokinetic muscle strength, and functional knee test scores. When groups were compared separately, measurements of the cross-sectional area of the thigh muscles revealed a difference in the quadriceps and total thigh size of the braced group between 3 and 6 months. The authors also reported that MRI data revealed 3 new meniscus injuries in the braced group but no new meniscus injuries in the non-braced group. Analysis of MRI also revealed an increase in the number of degenerative cartilaginous changes in the tibiofemoral joint in the non-braced group (7 subjects) versus the braced group (4 subjects).

The authors argued that, because postoperative bracing did not appear to protect the ACL when ligament laxity was measured by KT-1000 testing, the study supported the literature. They further concluded that the study showed that use of a brace after 6 months places the thigh musculature at risk for quadriceps femoris weakness, whereas this was not found in the non-braced subjects. In addition, the researchers reported that the Cincinnati knee scores for the braced group improved significantly at 3 months, despite the greater amount of thigh atrophy reported early after the operation. Finally, the authors concluded that the use of bracing did not minimize the risk for postoperative injuries to the cartilage or meniscus.

Aimee Klein, PT, OCS MGH Institute of Health Professions Boston, Mass