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

Structures at Risk from an Intermetatarsal Screw for Lapidus Bunionectomy

Category: Midfoot/Forefoot Introduction/Purpose: The Lapidus procedure is a common procedure for the treatment of hallux abducto valgus. Traditional fixation consists of two crossing screws in the sagittal plane. Despite arthrodesis of the first tarsometatarsal joint, recurrence of the hallux abducto valgus deformity remains a concern. A transverse screw spanning the base of the first metatarsal to the base of the second metatarsal has been advocated to provide transverse plane stability. However, the neurovascular bundle is located within the proximity of this screw. The literature is sparse with a standard technique to safely provide appropriate fixation. An anatomic cadaver study was undertaken to assess the risk of injury to the neurovascular bundle. Methods: Ten unmatched cadaveric limbs that had been disarticulated at the knee were used. Under fluoroscopic guidance, the guide wire to a 4.0-mm screw was driven across the base of the first metatarsal and into the second metatarsal. A 4.0-mm screw was inserted, taking care to obtain osseous purchase into the second metatarsal. A longitudinal incision was made and careful dissection was carried to identify the neurovascular bundle and screw. The neurovascular bundle was inspected for trauma and the proximity of the screws was measured using a digital caliper. Results: There were three left-sided and seven right-sided specimens. Five of the specimens were male and five were female. The mean age of the specimens at date of death was 71.4 years. The mean body mass index was 20.5. The mean distance from the 4.0-mm screw to the first metatarsal base 11.24 mm distal to the first tarsometatarsal joint. The deep plantar artery and deep peroneal nerve was free from injury in 10/10 (100%) specimens. However, the screw was measured to be less than 5 mm in three specimens. In these instances, the average distance of the screw distal to the first tarsometatarsal joint was 12.1 mm. Conclusion: The addition of the intermetatarsal screw for Lapidus bunionectomy is widely accepted clinical practice. Descriptions of the operative technique for the placement of hardware into the second metatarsal have not included specific recommendations to avoid potential risk to the neurovascular bundle as it courses between the bases of the first and second metatarsals. According to this cadaveric study, the neurovascular bundle was avoided with placement of the intermetatarsal screw, if placed approximately 11.24 mm distal to the first tarsometatarsal joint. Further study is warranted to evaluate the optimal distance distal to the first tarsometatarsal joint

Structures at Risk with Plantar Approach Retrograde First Metatarsal Charcot Beam Screw Insertion

Category: Diabetes, Midfoot/Forefoot Introduction/Purpose: The plantar approach for medial column retrograde intramedullary fixation of Charcot midfoot deformity allows for easy access to the ideal starting point on the metatarsal head and is supported by good clinical outcomes data. The primary argument against this approach is iatrogenic damage to the plantar structures of the metatarsophalangeal joint (MTP), which could cause tendon imbalances resulting in hallux malleus deformity. However, thus far, such complications have rarely been reported. Based on available literature, it is unclear what types of plantar structure injury occur and at what frequency. The purpose of this study was to describe plantar first metatarsophalangeal joint structure damage caused by plantar approach retrograde intramedullary medial column beam fixation. Methods: This was an IRB-exempt study. For each of 10 human cadaveric specimens, a 6.5 mm cannulated screw system was used for plantar approach retrograde medial column intramedullary fixation. This entailed using fluoroscopy to percutaneously localize a 2.8-millimeter (mm) guide wire to the center-center position on the first metatarsal head and then advanced it into the center of the medial cuneiform. A small sagittal plane skin incision was made around the wire and subcuticular tissue was bluntly divided. Next, a 4.8-mm cannulated drill was passed through a drill sleeve over the wire. Then, a countersink was used without a tissue protector. Finally, the 6.5-mm screw was inserted until it was recessed beneath subchondral bone. The specimens were then dissected to evaluate damage to the plantar structures of the 1st MTP joint. Damage to named structures was categorized as none, less than 50%, greater than 50%, and 100%. Results: The plantar plate was less than 50% damaged in all specimens. The flexor hallucis longus (FHL) tendon had less than 50% damage in 8 specimens. In one of two specimens with greater than 50% FHL damage, the torn portion of the tendon was tenodesed to the first metatarsal head by the screw (Figure). Although the medial flexor hallucis brevis (FHB) tendon was less than 50% damaged in 3 specimens and undamaged in the remainder, the medial sesamoid was less than 50% damaged in 8 specimens. In contrast, less than 50% damage occurred to the lateral FHB and lateral sesamoid in only 2 and 3 specimens, respectively. Additionally, some erosion of the plantar base of the proximal phalanx was observed in one specimen. Conclusion: The plantar structures of the hallux MTP are a tightly constrained system, which are violated during plantar approach retrograde intramedullary medial column fixation. No structures were completely transected and high-grade damage (greater than 50%) was infrequent, occurring in only two FHL tendons. Low-grade damage (less than 50%) was frequently observed to involved the FHL, medial sesamoid, and plantar plate. Based on the current findings, an FHL splitting or preserving approach is advisable to avoid high-grade damage if plantar approach is desired. A dorsal arthrotomy approach avoiding plantar structures may also be considered

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

Tissue Augmentation with Allograft Adipose Matrix For the Diabetic Foot in Remission

Background:. Repetitive stress on the neuropathic plantar foot is the primary cause of diabetic foot ulcers. After healing, recurrence is common. Modulating plantar pressure has been associated with extension of ulcer free days. Therefore, the goal of this study was to determine the effects of an injectable allograft adipose matrix in providing a protective padding and reducing the pressure in the plantar foot. Methods:. After healing his recurrent ulcer using total contact casting, a 71-year-old man with a 9-year history of recurrent diabetic foot ulcers was treated with injection of allograft adipose matrix, procured from donated human tissue. This was delivered under postulcerative callus on the weight-bearing surface of the distal end of the first ray resection. As is standard in our clinic for tissue augmentation procedures, our patient underwent serial plantar pressure mapping using an in-shoe pressure monitoring system. Results:. There was a 76.8% decrease in the mean peak pressure due to the fat matrix injected into the second metatarsal region and a 70.1% decrease in mean peak pressure for the first ray resection at the site of the postulcerative callus. By 2 months postoperatively, there was no evidence of residual callus. This extended out to the end of clinical follow-up at 4 months. Conclusion:. The results from this preliminary experience suggest that allograft adipose matrix delivered to the high risk diabetic foot may have promise in reducing tissue stress over pre- and postulcerative lesions. This may ultimately assist the clinician in extending ulcer-free days for patients in diabetic foot remission