Postoperative CT-scan 3D reconstruction of the calcaneus following lateral calcaneal lengthening osteotomy for flatfoot deformity in children. Is the surgical procedure potentially associated with subtalar joint damage?

BACKGROUND: Several anatomical studies have shown that the articular facets of the calcaneus can present with different anatomy. This study assessed the 3D anatomy of lateral calcaneal lengthening (LCL) osteotomy in relation to the anterior and middle facet of the calcaneus in a group of skeletally immature patients treated for symptomatic flatfoot deformity.

METHODS: During the study period, 14 consecutive patients (10 males, 4 females) presenting symptomatic flatfoot (20 feet) with different aetiologies underwent LCL osteotomy and CT scan with 3D reconstruction of the operated feet. Anatomy of articular factes of the calcaneus were graded according to Bunning & Barnett's classification. In order to assess clinical and functional outcome, all patients were evaluated according to Yoo et al.'s, Mosca's and AOFAS clinical criteria before surgery and at last follow-up visit.

RESULTS: Despite proving difficult to assess (10 out of 20 feet), dimensions of bone and joint structures revealed significant anatomical variations. In particular, working to Bunning & Barnett's classification, anatomy of the articular facet varied significantly among patients, and in Bunning & Barnett type-B1 or B2 the LCL osteotomy necessarily violates the articular surface of the anterior and middle facet of the calcaneus due to the fact that the two facets are fused together (single articular surface).

CONCLUSIONS: These biometric notions allow a better understanding of the impact on articular facets of the calcaneus of the osteotomy procedure suggested by Evans and Mosca. We anticipate that the findings reported here should lead to improved techniques for assessing all bone structures of the hindfoot, support logical classifications of the different pathological situations, and ultimately lead to improved treatment strategies.