SLR - November 2022 - Michelle K. Yoakim, DPM
Title: Supramalleolar osteotomy for the treatment of ankle osteoarthritis leads to favourable outcomes and low complication rates at mid-term follow-up: a systematic reviewReference: Butler JJ, Azam MT, Weiss MB, Kennedy JG, Walls RJ. Supramalleolar osteotomy for the treatment of ankle osteoarthritis leads to favourable outcomes and low complication rates at mid-term follow-up: a systematic review [published online ahead of print, 2022 Sep 23]. Knee Surg Sports Traumatol Arthrosc. 2022; September 23; doi:10.1007/s00167-022-07144-7.
Level of Evidence: Level IV, Systematic review
Scientific Literature Review
Reviewed By: Michelle K. Yoakim, DPM
Residency Program: North Colorado Podiatric Medicine and Surgery Residency - Greeley, CO
Podiatric Relevance: Supramalleolar osteotomy (SMO), a joint preserving procedure for early-to-mid-stage asymmetric varus and valgus ankle osteoarthritis, involves transferring the asymmetrically loaded joint contact pressure away from the arthritic regions. SMO is believed to reduce shear forces within the joint, allowing for natural gliding between the talus and tibia. However, critical evaluation of the clinical and radiographic outcomes, complications, and survival rates after an SMO are lacking. Thus, the authors performed a systematic review of SMO for ankle osteoarthritis as well as the level and quality of evidence of the included studies.
Methods: This level 4 systematic review of MEDLINE, EMBASE, and Cochrane Library found 7571 clinical studies. Only 24 studies—with a total of 1182 ankles (1160 patients)—met criteria: in English, at least 10 patients, and at least a 2-year follow-up period. Level of evidence (LOE) was assessed using The Journal of Bone & Joint Surgery (JBJS) criteria, the quality of evidence (QOE) with the Modified Coleman Methodology Score (MCMS), and bias with the methodological index for nonrandomized studies (MINORS) criteria. Extracted data included patient demographics, surgical procedure characteristics, objective and subjective outcomes, range of motion, post-operative imaging, complications, failures, and reoperations. Lastly, statistical analysis was done using SAS software.
Results: Per JBJS criteria, 2/24 studies were LOE 2, 3/24 LOE 3, and 19/24 LOE 4. Using MCMS to measure quality, 0/24 studies were excellent, 2/24 good, 17/24 fair, and 5/24 poor, with a mean of 59.3/100. The mean MINORS criteria score was 9.5, indicating an overall low quality of evidence in the literature. 52.2% of patients were male, mean age was 51.8 years old, mean BMI was 26.8 kg/m2, and mean follow-up time was 50.4 months. 401/1160 patients were treated for post-traumatic osteoarthritis and 697/1182 ankles had a varus deformity. The medial opening-wedge osteotomy was most commonly used for varus deformity and the medial closing wedge osteotomy for valgus deformity. 21/24 studies reported AOFAS score with a mean preoperative score of 52.6 and a mean postoperative score of 78.1. Radiographic data was reported in all studies, with tibial anterior surface (TAS) angle being the most commonly measured and 41.4% of the ankles treated being classified as a modified Takakura 3a. Complications were listed in 13/24 studies with the most common being non-union. 327 patients required secondary procedures with the most common being implant and hardware removal.
Conclusions: The authors concluded that early-to-intermediate-stage ankle osteoarthritis may safely and effectively be treated using SMO with good outcomes, low failure rates, and moderate reoperation rates. Despite conflicting evidence in the literature, this study also concluded that SMOs are effective for severe arthritis, younger patients, and for a select population of older patients. The study limitations highlighted the shortcomings of current literature and included results stemming from studies with poor designs, short follow-up periods, and an overall low level and quality of evidence and thus a need for more high-level studies.