|
Year |
2002 |
|---|---|
|
Question Number |
143. |
|
Category |
Sports Medicine |
Question
A 25-year-old man has had medial knee pain for the past 5 years that has been worsening over the last six months with a progressive varus deformity of the leg. History reveals he underwent partial medial menisectomy at age 16 years. Examination reveals no knee effusion, active range of motion from 3 deg to 125 deg, a positive Lachman test, increased lateral joint line opening of 6mm, and a standing mechanical axis of 11o of varus. What is the next most appropriate step in treatment?
1- Meniscus allograft
2- Posterolateral reconstruction
3- ACL reconstruction
4- High tibial osteotomy
5- Supracondylar femoral osteotomy
Figures
Answer (click for answer)
Preferred Response: 4
The patient gives the history of previous knee operation because of injury to his medial compartment (medial menisectomy) with resultant progression of a varus deformity (medial compartment collapse), ACL deficiency (positive Lachman) and posterolateral ligament laxity. The patient has had gradual collapse of his medial compartment with increasing pain and malalignment. The patient’s posterolateral ligaments have been stretched/traumatized by this increase in the varus alignment of the knee. The patient likely has had marked articular cartilage damage. The patient’s problem lies in the fact that he no longer adequately distributes his weight over the entire weight-bearing surface of his tibia (he distributes more over the medial side). In order to correct this problem his mechanical axis needs to be brought back in line with his anatomic axis (Normally the mechanical axis of the tibia is the same as the anatomical axis).
The key to addressing this patient’s problem is to bring the knee back into alignment. At this point in time the meniscus allograft would fail to adequately address the varus malalignment of this patients knee. Posterolateral reconstruction would address the ligament laxity, but would fail to adequately address the cause of the problem (malalignment). ACL reconstruction would give some stability back to the knee, but without concurrent correction of the weight-bearing surface of the knee and loss of the secondary stabilizers (medial meniscus/posterolateral corner) it would be placed under unusually high stress. Supracondylar femoral osteotomy wouldn’t address some of the ligamentous laxity in his knee.
The article cited is a study of 41 patients with lower limb varus deformity and ACL deficient knees. The patients were all treated with high tibial osteotomy, followed by ACL reconstruction (in the majority, 34/41) at a mean of eight months later (All patients had their ACL reconstructed, and there were four revision ACL). Posterolateral reconstructions were also required in eighteen of the patients. Six patients had meniscal allografts at the time of ACL reconstruction. Thirty of the patients had articular cartilage abnormalities at the time of the initial surgery. Mean follow-up for the patients was 4.5 years. Correction of the varus alignment was maintained in 80% (33/41) of the knees. At follow-up 1 patient rated his knee as normal, 14 as very good, 14 as good, 10 as fair and 2 as poor. Post-operatively the gait analysis showed medial compartment load decreased to values equal to controls (significant). The authors’ goal was to align the weight-bearing axis of the knee with a closing wedge osteotomy of the tibia, followed by ligament reconstruction. The authors’ advocate early correction of young patients with chronic ACL deficiency, varus angulation, loss of medial meniscus and posterolateral ligament insufficiency.
Reference: *Noyes FR, et al. High tibial osteotomy and ligament reconstruction for varus angulated anterior cruciate ligament-deficient knees. Am journal of sports medicine, Vol 28: 282-295.