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.