To the Editor:

Dr. Grelsamer has mentioned a very good point on choosing the site of osteotomy when correction of the valgus deformity of the knee is indicated. Traditionally, a corrective osteotomy is performed at the site of deformity to create a horizontal joint line. However, if the valgus deformity of the knee exceeds 12 degrees and there is depression of the lateral tibial plateau as depicted in Figure 2 of our article, the issue concerning the proper site of corrective osteotomy is raised.

In our series, two of 30 knees with valgus deformity resulted from old fracture of the lateral tibial condyle. The tibiofemoral angles of both knees were 15 degrees of valgus before osteotomy. At that time, we followed the principles of Coventry[1],-- if the valgus angulation of the knee exceeds 12 degrees, the osteotomy should be done at the supracondylar area of the femur. Both knees had adequate correction of the deformity to 0 degrees of tibiofemoral angulation immediately after osteotomy. At the recent follow-up (8 years postoperatively) of both knees, the tibiofemoral angulation was 1 degree and 2 degrees of varus respectively and both patients were satisfied with the result.

We think Dr. Grelsamer has raised a very good issue in this particular situation, which we believe, has not been mentioned before. We consider if adequate correction is performed either by distal femoral or proximal tibial varus osteotomy, a satisfactory clinical result will be anticipated. As to the technique of the osteotomy, we prefer distal femoral varus osteotomy partly because we are familiar with this technique, and partly because we are concerned possible injury to the peroneal nerve if 15 degrees or more of varus correction is to be done. Importantly, if the deformity is not overcorrected is not for fear of nerve injury, the deformity may recur[2].

--- Jun-Wen Wang, MD Chin-Chen Hsu, MD Corresponding author: Jun-Wen Wang, MD Department of Orthopaedic Surgery, Chang Gung Memorial Hospital at Kaohsiung

No. 123 Ta Pei Rd., Niao Sung Hsiang, Kaohsiung Hsien, Taiwan, Republic of China

References:

1. Coventry MB. Proximal tibial varus osteotomy for osteoarthritis of the lateral compartment of the knee. J Bone Joint Surg AM 1987;69:32-8.

2. Maquet PGJ. Biomechanics of the knee: with application to the pathogenesis and the surgical treatment of osteoarthritis. 2nd ed. New York: Springer; 1984. p.276.

To the Editor:

The authors should be congratulated on a series of technically well- executed osteotomies. However, because orthopaedists in training use this Journal as a foundation for their education I am concerned about the message that this paper delivers.

Specifically, the authors appear to have violated the traditional principle that an osteotomy about the knee should be carried out on the side of the deformity. The penalty for this violation is usually an oblique joint line, persistent pain, and a challenging knee replacement.

Figure 2 a-c shows a patient whose valgus is secondary to an impressive deficit of the lateral plateau. The distal femur is normal. Yet, the authors have performed a femoral osteotomy that has predictably led to an oblique joint line. At eight years, the authors report that the patient is doing well. We do not know if or when the patient will need a joint replacement or how challenging that arthoplasty will be. Would a relatively easy primary knee replacement not have been preferable as the index procedure?

Should we no longer be teaching that an osteotomy is preferably performed on the side of the joint where the deformity lies?

Either way, these principles should have warranted a serious discussion at some point in the paper. Perhaps it is not too late.