Correction of Bilateral Genu Varum for a High Level Athlete

Abstract

The correction of genu varum for patients with medial compartment osteoarthritis is a well established treatment with the goals of reducing knee pain and slowing the progression of knee arthritis. A full correction of the varus and even overcorrection are needed to achieve these goals. The use of osteotomy in patients with genu varum to prevent arthritis from ever occurring is more controversial. The following case will present the story of an elite soldier whose job requires him to be in top physical condition. His experience with realignment surgery and ability to recover and surpass his pre op athleticism will be described.

Brief Clinical History:

This is a 33 year old male who is part of the United Sates special forces who began experiencing medial knee pain with running and other high impact activities. He had bilateral genu varum since childhood and attributed the pain to this deformity. He was found to have varus deformity limited to the coronal plane involving the right proximal tibia and the left proximal tibia and distal femur. He was keen anatomic reduction of the deformities with external fixation with the goal of return to high impact activities surpassing his pre op function.

Preoperative Problem List

• Bilateral symptomatic genu varum without arthritis
• High level athlete

Treatment Strategy

The plan was to correct the left side first including both femoral and tibial osteotomy. The femur osteotomy was done with an acute correction method using static external fixation. Osteoplasty of the ipsilateral tibia with external fixation was performed simultaneously. The tibia deformity was corrected gradually to ensure a perfect mechanical axis alignment. The right side was corrected 6 weeks later. This gave the left side adequate time to heal. The left side then became the strong side and supported the newly operated right side. Right side correction required only the tibial osteotomy and a uniplanar fixator.

Basic Principles

Femoral osteotomy with external fixation can be done percutaneously, with minimal blood loss and allows immediate post op weight bearing. Femoral osteotomy with a plate requires an open approach to the femur, is associated with greater blood loss, and requires protective weight bearing. Opening wedge osteotomy with plating also requires bone grafting.

Gradual correction of the tibial deformity is accomplished with external fixation. Uniplanar deformity is addressed with a monolateral frame, whereas, multiplanar and oblique plane deformities are more effectively corrected with circular fixation. Hydroxyapatite coated, tapered, 6mm half pins provide excellent fixation. Patients perform adjustments at home after a short latency period. Deformity correction proceeds at 1mm per day and takes from 10-21 days. The alignment is adjusted until the desired mechanical axis is achieved as measured on 51” standing radiographs.

Technical Pearls:

The use of cannulated half pin insertion technique has made the application of unilateral external fixators more accurate. A wire is used to find the ideal insertion point for the first half pin. A cannulated drill is slid over the wire and both cortices are drilled. The half pin is then placed into the drill hole. Monolateral fixators are extremely unforgiving and this method has made application easier.

Avoiding and Managing Problems

In active patients tibial fracture through a pin hole is a concern as is collapse of the newly formed regenerate bone. Although these complications are extremely rare they remain a concern immediately post frame removal. The protocol used after frame removal includes the use of a hinged knee brace with maximum of 50% weight bearing for 2 weeks. Patients are then allowed to discontinue the brace and progress to full weight bearing after obtaining a new x-ray. Patient can then resume low impact exercises. Running and sports are allowed 3 months after frame removal.

References and Suggested Reading

1. Ashfaq K, Fragomen AT, Nguyen JT, Rozbruch SR. Correction of proximal tibia varus with external fixation. L Knee Surg. 2012 Nov;25(5):375-84

2. Fragomen AF, Rozbruch SR. “Proximal Tibial Osteotomy for Medial Compartment osteoarthritis of the Knee Using the Taylor Spatial Frame” Techniques in Knee Surgery 2005;4(3):173-18

3. Rozbruch SR, Fragomen A, Ilizarov S. “Correction of tibial deformity with use of the Ilizarov/ Taylor Spatial Frame”. JBJS-Am 88-A 2006, Suppl. 4:156-174

4. Bae DK, Song SJ, Kim HJ, Seo JW. Change in limb length after high tibial osteotomy. Knee Surg Sports Traumatol Arthrosc. 2013 Jan;21(1):120-6

5. Paley D, Herzenberg J. Realignment for mono-compartment osteoarthritis of the knee. Pp479-509. Chapter 16 in Principles of deformity correction. Springer-Verlag Berlin 2002

Posted: 7/29/2014

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