Changes in ankle joint motion after Supramalleolar osteotomy: a cadaveric model

Pressure change at ankle joint in supramalleolar osteotomy with or without fibular osteotomy according to different types of varus ankle

The need for additional fibular osteotomy (FO) when performing supramalleolar osteotomy (SMO) in the varus ankle arthritis (VAA) is controversial. Some cadaveric studies have been performed to prove this; however, it is difficult to implement deformities including talar tilting and translation in cadavers. In this study, we created a model of VAA with the tilting and translation using three-dimensional (3-D) finite element (FE) analysis and analyzed the results of SMO with or without FO depending on the types of VAA. The validated normal foot and ankle 3-D FE model was constructed including the ankle cartilages of the talar dome and tibia plafond. The VAA models were determined and reconstructed by following the classification of VAA, VAA with medial translation for stage 3a, VAA with varus tilting (7.5°) for stage 3b. The postoperative SMO models (SMO with and without FO) were reconstructed by corresponding to each VAA models. The FE analysis conditions were commonly applied. The boundary condition of ankle joint was defined as "sliding condition" and applied 0.002 friction coefficient to realize lubricative property. Loading condition was assumed as a two-leg standing position and half of the subject body weight (325 N) was loaded on center of ground to vertical direction. Contact pressure changes were predicted at the medial ankle cartilage. As a result, in VAA with medial translation, isolated SMO may provide sufficient pressure reduction at the medial ankle joint. However, in VAA with varus tilting, SMO combined with FO could appropriately relieve concentrated pressure at the medial ankle joint.

Outcomes of oblique supramalleolar osteotomy without fibular osteotomy for congruent- and incongruent-type medial ankle arthritis

BACKGROUND

Although high talar tilt and ankle mortise incongruence are risk factors for supramalleolar osteotomy (SMO), no study on lateral talofibular joint congruence exists. We aimed to evaluate the outcomes of oblique SMO without fibular osteotomy for medial ankle arthritis and compare them according to the lateral talofibular joint congruity.

METHODS

Forty-eight ankles were retrospectively reviewed and divided according to preoperative talofibular joint congruity (congruent, 22 [45.8%] vs. incongruent, 26 [54.2%]).

RESULTS

The mean VAS score, AOFAS score, and modified Takakura stage were significantly improved. No significant differences were noted in clinical outcomes, but the mean postoperative tibiotalar angle and difference between the upper and lower talofibular gaps were significantly different in both groups (p = 0.004 and p = 0.009, respectively). The mean Takakura stage at 1 and 2 years after surgery was higher in the incongruent group (p = 0.013, p = 0.012).

CONCLUSION

This procedure was effective against early- to mid-stage medial ankle arthritis. Radiographic arthritic grade changed according to the talofibular joint congruity.

Reconstruction of Severe Ankle and Pilon Fracture Malunions

Malunion of ankle and pilon fractures has significant detrimental effect on function and development of post-trauma osteoarthritis. Unfortunately, the incidence of malunion has been reported to be increasing. It is important to assess the ankle for congruency, because this determines the level where correction will occur. A plethora of techniques are available, with low-level evidence supporting each, and therefore it is important that the treating surgeon is fully prepared and comfortable in the techniques they are to use. Supplementary procedures are common and should be expected. This article provides a review of current methods of treatment and their outcomes.