SLR - March 2021 - Stephen Smith

Functional and Radiological Medium Term Outcome Following Supramalleolar Osteotomy for Asymmetric Ankle Arthritis- A Case Series Of 33 Patients 

Reference: Ayyaswamy, Brijesh, et al. “Functional and Radiological Medium Term Outcome Following Supramalleolar Osteotomy for Asymmetric Ankle Arthritis- A Case Series Of 33 Patients .” Journal of Orthopaedics, vol. 21, 8 Sept. 2020, pp. 500–506., doi:10.1016/j.jor.2020.08.038. 

Level of Evidence: Level IV, retrospective study

Scientific Literature Review 

Reviewed By: Stephen Smith, DPM
Residency Program: Inspira Medical Center – Vineland, NJ

Podiatric Relevance: The purpose of this retrospective study was to determine if positive outcomes could be expected from this joint sparing procedure with a medium term follow-up of 6 years.  This paper addresses both varus and valgus deformity treatment with a joint sparing procedure. 

Methods: This study included 33 patients who had supramalleolar osteotomies treating asymmetric arthritis due to varus or valgus deformity. The exclusion criteria for this article were sagittal plane deformity, infection, inflammatory arthritis, peripheral neuropathy, vascular disease, BMI greater than 35, osteoporosis, and pan-ankle arthritis as confirmed on arthroscopy. Of the 33 patients, 21 had varus deformity and 12 valgus. Average age was 57, average follow up of 72 months. Patients were given a choice of arthrodesis, arthroplasty, or osteotomy. Radiographic evaluation included tibial articular surface, hindfoot alignment angle, and tibiotalar joint congruence. Wedge size was determined by the equation: tan α = H/W. Intervention consisted of a closing wedge osteotomy fixated with plates. Patients were non-weight bearing for six weeks. The authors described a failure as persistent or worsening of symptoms and further progression of arthritis on radiographs. Outcome was determined using AOFAS and VAS pain scale scoring, also included were radiographic evaluation of angle correction. 

Results: There were improved functional outcomes of patients in this study from a preoperative AOFAS mean of 33.9 to postoperative 78.7. VAS score improved from 8.4 to 3.4. Using Colin et al’s criteria AOFAS score this technique produced good to excellent results in 87 percent of patients at six year follow-up. The authors note improvement of all measured angles to within normal limits. The average time to union of the osteotomy was 8.6 weeks, with no nonunions reported. The data set included three failures with two ankle arthrodesis and one TAR. The overall success at six years was 90.9 percent. 

Conclusions: This paper described high success rates with a supramalleolar osteotomy for partial ankle arthritis in varus and valgus deformities at six years. These results suggest surgeons should add the closing base wedge osteotomy for treatment of these conditions given positive results without progression to joint destructive procedures. Key highlights of the paper include low failure rate of 9 percent, with good to excellent AOFAS scores, no incidence of nonunion given their closing wedge technique, and osteotomy union at an average of eight weeks. The radiographic angles measured improved to within normal limits which validate the authors' technique and use of the equation: tan α = H/W for wedge determination. With no noted change in the radiographic angles over the six-year follow-up, the correction was maintained as expected. These results suggest that in the properly selected patient with confirmation on arthroscopy of non-total joint arthritis, closing base wedge supramalleolar osteotomy can provide favorable results for an extended period of time. 

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