A chevron cut may ofer more stability
The simplest addition to the tendon transfer procedures was a transverse osteotomy of the posterior calcaneum with medial translation of about 1cm, and internal fixation with one or more screws. Originally described by Koutsogiannis (1971), this technique has been promoted particularly by Myerson. The osteotomy is made 1cm posterior and parallel to the peroneal tendons. A chevron osteotomy with the apex anteriorly has been proposed to increase stability and allow earlier weightbearing. The biomechanical rationale is that realigning the vector of the Achilles tendon will transform this tendon from an evertor of the subtalar joint to a neutral effect.
The largest series is that of Myerson (2004). In 120 patients, pain and function were markedly improved in 90%, and arch height was also restored with few recurrences. Poor results were mainly in those with severe deformity pre-operatively.
Two smaller series using FDL (Guyton 2001, Wacker et al (2002)) and one using FHL (Sammarco 2001) reprted good clinical results but less improvement in the arch: Sammarco had no patients with improvement in clinical or radiological measures of arch, Guyton had 50% and Wacker 75% (with 10% recurrence at 3-5y).
This procedure appears able to give a more durable result than tendon transfer alone. Outcome measures are relatively consistent between series, with reasonably good improvement in pain and function but variable effects on arch height. It will be important to see whether these results are maintained in a procedure which does not fully correct foot alignment.
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| Medial displacement calcaneal osteotomy. A chevron cut may ofer more stability |
The posterior fragment is moved medially about 1cm | One screw is usually enough to stabilise the osteotomy |
| The osteotomy is usually combined with Achilles or gastrocnemius lengthening, debridement of tibialis posterior tendon, FDL or FHL transfer into the navicular (or a Cobb transfer), and often with a spring and/or deltoid ligament reconstruction | ||