Deformity correction has become a more common intervention in an attempt to mitigate pain from an arthritic ankle while hopefully preventing progression of intraarticular disease. Malunion takes the form of angulation, rotation, translation, and length discrepancy, all of which must be measured and addressed by the surgeon. Contact surface area within the ankle joint can decrease up to 40% with angular malalignment, with subsequent increase in contact pressures in the residual joint surface. As the apex of the deformity moves closer to the ankle joint, pressures increase further. There are no rules as to the magnitude of deformity that necessitates correction, but the literature suggests 15 degrees of varus alalignment, 10 degrees of valgus malalignment and 20 mm shift medial to the mechanical axis all should undergo correction. This lecture will explore: assessment of deformity, methods of correction, and literature results on the impact deformity correction has on ankle arthritis. As a separate issue, we will also address fibula length and the impact that shortening has on creating ankle arthritis and flatfoot.
Crossover second toe deformity is a multiplanar deformity derived from multiple etiologies with the common endpoint of metatarsophalangeal joint instability. The stability of the joint is compromised through laxity of the volar plate, secondary rupture of the lateral collateral ligament, and ultimately dorsal subluxation or dislocation of the metatarsophalangeal joint. The digital malalignment often includes a hammertoe deformity, but should not be confused with a routine clawtoe. Elimination of alternative diagnoses relies on precise palpation to negate Morton's neuroma, 2nd metatarsalgia, Freiberg's infraction, and 2nd metatarsal stress fracture. Radiographs assist in the diagnosis in not only eliminating the above mentioned differential diagnoses, but also in evaluating confounding anatomic variables such as hallux valgus, metatarsus primus varus, and metatarsal length. These variables may necessitate additional osteotomies in conjunction with ligament reconstruction to minimise recurrence. Operative intervention has revealed long term failure of secondary ligament reconstruction, mandating tendon transfers such as the flexor-to-extensor and the extensor digitorum brevis to support the repair. We will explore these techniques and subsequent modifications to achieve patient satisfaction.
Tarsometatarsal arthritis must be evaluated in conjunction with naviculocuneiform joint arthritis, as the two generally coexist. Primary osteoarthritis or systemic arthritis generally leads to uncomplicated non-deformity correction through arthrodesis. Challenges in correction become more pronounced following Lisfranc injury, where deformity and ligament instability introduce malalignment that mandates osteotomies to correct deformity. Diagnosis hinges on both CT scan data and selective diagnostic injections under fluoroscopy. The surgeon must simultaneously consider minimising bone resection to lessen the impact of metatarsal shortening. In addition, the three columns of the foot must be respected with reference to midfoot arthrodesis rules, introducing challenges in operative reconstruction as the lateral column mandates preserved flexibility. In addition, collapse at the midfoot often leads to a rigid pes planovalgus deformity, and the surgeon must consider when it is appropriate to add a medial slide calcaneal osteotomy and gastrocnemius recession. Finally, naviculocuneiform joint arthrodesis, if required, introduces significant technical challenges in both alignment and fixation that will be addressed.
