Anatomic Description of the Anterior Body Calcaneal Z-Osteotomy

Category: Ankle Introduction/Purpose: Flexible pes planovalgus is a common condition encountered by foot and ankle physicians. Many treatment options exist to correct this deformity. One such procedure is an Evans osteotomy of the anterior process of the calcaneus. Due to the complications seen with this type of osteotomy, there has been an attempt to reduce these complications and as a result, an anterior body calcaneal z-cut osteotomy was developed. This osteotomy is inherently more stable by design and fewer complications have been reported. In an attempt to further understand this osteotomy and to determine how much bony interface remained following this osteotomy, a cadaveric study was performed. Methods: A Z-cut osteotomy was performed on 10 cadaveric specimens with the distal arm exiting dorsal and 1 cm proximal to the calcaneocuboid joint, while the proximal arm exited plantarly. The central axis lengths of 15 mm and 20 mm were compared. An 8-mm wedge was placed in both the distal and proximal arms, and fixated with a staple. Digital calipers were used to measure the amount of bony apposition on the central arm between the wedges. Results: The average amount of bone apposition was 9.13 mm. When comparing the 20 mm to 15 mm central arm groups, the average bony apposition was 10.66 mm and 7.61 mm, respectively. Conclusion: Based on these results, the anterior body calcaneal Z-osteotomy provides enough bony apposition between both groups with an 8-mm wedge distraction. Further studies are warranted to evaluate the union rate between the classic lateral column lengthening osteotomy and the anterior body calcaneal Z-osteotomy

Intramedullary Screw Fixation and Relevant Diameter of the Proximal Phalanges of the Foot

Category: Midfoot/Forefoot Introduction/Purpose: The average intramedullary diameter of the proximal phalanges of the foot has not been well documented in the literature. This dimension has important implications for surgical fixation devices, such as intramedullary screws. By design, intramedullary fixation devices rely on endosteal fit to provide stability. The precise intramedullary diameter is not readily identifiable on plain radiographs. A better understanding of the average diameter of the proximal phalanges of the foot can assist surgeons in surgical planning and appropriate screw diameter selection to provide more satisfactory patient outcomes. Methods: Twenty below-knee cadaveric specimens were dissected to expose each proximal phalanx. A sagittal saw was used to transect the diaphysis at its narrowest portion. The dorsal to plantar and medial to lateral diameters were measured using a digital manometer. Results: The average diameter dorsal to plantar for each digit was 6.25 ± 2.24 mm, 3.61 ± 1.25 mm, 2.94 ± 0.70 mm, 2.72 ± 0.77 mm, and 2.48 ± 0.80 mm, respectively. The average diameter medial to lateral for each digit was 7.83 ± 2.13 mm, 3.08 ± 0.93 mm, 2.47 ± 0.74 mm, 2.33 ± 0.73 mm, and 2.62 ± 0.69 mm, respectively. The overall average diameter for toes one through five was 7.04 ± 1.95 mm, 3.35 ± 1.04 mm, 2.71 ± 0.66 mm, 2.52 ± 0.71 mm, and 2.55 ± 0.63 mm, respectively. Conclusion: Understanding the intramedullary diameters of the proximal phalanges of the foot is a valuable tool when utilizing intramedullary surgical stabilization. The hallux proximal phalanx demonstrated the largest, and most variable, diameter, which could make selection intramedullary fixation difficult. In addition, the hallux proximal phalanx may lend itself better to 2 smaller fixation devices rather than one larger one. The lesser phalanges demonstrated smaller diameters more consistently, which is more amenable to a single smaller (2.5 mm) intramedullary device. This data can provide surgeons with an expected intramedullary diameter during surgical planning