Abstract

Introduction and Aims: Treatment options for medial gonarthrosis include high tibial osteotomy (HTO). There has been a shift towards opening wedge techniques partially due a perceived higher complication rate with closing wedge techniques. This has not been our experience and we describe the outcome of a large series of closing wedge HTOs.

Method: We reviewed the case records of 313 patients who underwent a total of 374 closing wedge high tibial osteotomies by three surgeons for medial compartment gonarthrosis between 1989 and 2003. The mean outpatient follow-up was 16 months and the mean time post-surgery was 66 months. We identified any post-operative complications and the early clinical outcome including those known to have proceeded to joint replacement. The mean age of patient was 52 years (range 19–72). In all patients a laterally based wedge, mean size nine degrees (range 4–18), was excised and the osteotomy stabilised with one or two stepped staples.

Results: Outcome following closing wedge osteotomy was generally good, only six percent of patients complained of continuing knee pain, although not at a level that required further intervention. Symptoms in 3.5% of knees deteriorated and required total knee replacement at a mean of 63 months (range 16–112) following osteotomy. No intra-operative difficulties were encountered with these replacements. The complication rate was acceptable with an overall rate of 7.8%. One patient required revision shortly after surgery due to inadequate initial correction and one developed a transient peroneal nerve neuropraxia. There were no other neurovascular or intra-operative complications recorded. All the osteotomies united, although nine patients had delayed union, taking a mean of five months for their osteotomies to unite. Other complications included: five patients who had staples removed due to irritation, one who developed a stitch abscess and one who developed a deep wound infection. Two knees had a reduced ROM and required an MUA. In addition, six patients developed symptomatic DVTs, three with pulmonary emboli, but there were no deaths.

Conclusion: In our experience, closing wedge osteotomy for medial gonarthrosis is a safe and reliable procedure with a good early outcome and an acceptable complication rate of 7.8% in this series, with a low incidence of serious complications that compares favourably with the quoted complication rates for opening wedge techniques.

Recent surveys have shown that idiopathic structural scoliosis of mild degree is generally not progressive. We will propose a mechanism which may be responsible for deterioration in the few. It has been observed that the spinal cord, although displaced towards the concavity, does not rotate in company with the vertebrae, thus exposing the emerging nerve roots to the effects of traction and possibly of entrapment. We suggest that progression occurs when the neuraxis is unable to adjust to the change in the anatomy of vertebral column. Our proposition is based upon our findings in a complete spinal column obtained from a baby with structural scoliosis. Support is provided by intercostal angiography, and by observations upon normal anatomy, the pathological anatomy of mature scoliotic spines and the anatomy of contrived scoliosis in normal spines. Although our histological and electrophysiological investigations are incomplete we can demonstrate a significant increase in degenerate cells in the dorsal root ganglia at the apex on the convex side. Lack of suitable necropsy material prevents us from confirming our observations so that our report is inevitably preliminary. We enter a plea that careful examination of the neuraxis be undertaken whenever a specimen of a scoliotic spine becomes available.