Treatment of Metatarsalgia with Proximal Osteotomies

Metatarsal sliding osteotomy is effective without altering plantar pressure in Morton's neuroma: Retrospective case series

BACKGROUND

Various operative methods for the treatment of Morton's neuroma have been discussed, and osteotomy of the metatarsal bone has been reported recently. However, there has been no report of pedobarographic changes after metatarsal osteotomy. Pedobarographic changes of other metatarsal area after the surgery may cause transfer metatarsalgia, and thorough analysis of the pedobarographic data should be performed peri-operatively. The purpose of this study is to investigate the post-operative pedobarographic changes of sliding osteotomy of the 3rd metatarsal bone for treating Morton's neuroma.

METHODS

Forty patients (45 feet) who underwent metatarsal sliding osteotomy of the 3rd metatarsal bone for treating Morton's neuroma from November 2013 to December 2021 were retrospectively reviewed. Proximal sliding osteotomy was performed at the proximal 3rd metatarsal bone through dorsal approach. Clinical outcomes were evaluated with American Orthopaedic Foot and Ankle Society Lesser Metatarsophalangeal Interphalangeal Scale (AOFAS LMIS), Foot Function Index (FFI), and Visual Analogue Scale (VAS). Plain radiograph and pedobarogram were performed to evaluate the radiologic and pedobarographic outcomes.

RESULTS

AOFAS score was improved from 52.8 ± 9.0 (18-62) to 88.8 ± 9.8 (78-100) and FFI was improved from 61.8 ± 4.9 (50-70) to 32.2 ± 5.1 (23-42) on average. The 3rd metatarsal bone was shortened by 3.1 ± 0.8 mm and dorsally shifted by 1.5 ± 0.4 mm after the surgery. Plantar intermetatarsal distances between 2nd and 3rd and 3rd and 4th metatarsal heads were significantly increased post-operatively. Average forefoot pressure and maximum pressure of the 2nd to 4th metatarsal head were not significantly changed between pre-operatively and post-operatively.

CONCLUSION

Proximal metatarsal sliding osteotomy of the 3rd metatarsal bone shows a satisfactory result in both clinical and pedobarographical evaluations. It could be an effective treatment of permanent indirect decompression of Morton's neuroma with avoiding recurred neuroma, adhesion of tissue, paresthesia, and transfer metatarsalgia.

Distances from the deep plantar arch to the lesser metatarsals at risk during osteotomy: a fresh cadaveric study

Background

The deep plantar arch is formed by anastomosis of the lateral and deep plantar arteries. Osteotomy of the lesser metatarsals is often used to treat metatarsalgia and forefoot deformity. Although it is known that some blood vessels supplying the lesser metatarsals are prone to damage during osteotomy, there is little information on the distances between the deep plantar arch and the three lesser metatarsals. The aims of this study were to identify the distances between the deep plantar arch and the lesser metatarsals and to determine how osteotomy could damage the arch.

Methods

Enhanced computed tomography scans of 20 fresh cadaveric feet (male, n = 10; female, n = 10; mean age 78.6 years at the time of death) were assessed. The specimens were injected with barium via the external iliac artery, and the distance from the deep plantar arch to each lesser metatarsal was measured on axial and sagittal images.

Results

The shortest distances from the deep plantar arch to the second, third, and fourth metatarsals in the axial plane were 0.5, 2.2, and 2.8 mm, respectively. The shortest distances from the distal epiphysis to a line passing through the deep plantar arch perpendicular to the longitudinal axis of the lesser metatarsal in the sagittal plane were 47.0, 45.7, and 46.4 mm, respectively, and those from the tarsometatarsal joint were 23.0, 21.0, and 18.6 mm. The deep plantar arch ran at the level of the middle third, within the proximal portion of this third in 11/20 (55.0%), 7/20 (35.0%), and 5/16 (31.2%) specimens, respectively, and at the level of the proximal third in 9/20 (45.0%), 13/20 (65.0%), and 11/16 (68.8%).

Conclusions

Overpenetration into the medial and plantar aspect of the second metatarsal or the proximal and plantar aspect of the fourth metatarsal during shaft or proximal osteotomy could easily damage the deep plantar arch. Shaft or proximal osteotomy approximately 45-47 mm proximal to the distal epiphysis or 18-23 mm distal to the tarsometatarsal joint on the plantar aspect could interrupt blood flow in the deep plantar arch.

Entry points of nutrient arteries at risk during osteotomy of the lesser metatarsals: a fresh cadaveric study

Background

Osteotomies of the lesser (second to fourth) metatarsals are often used to correct forefoot deformities. However, certain areas of the lesser metatarsals where arteries may be prone to damage during surgery, and the resulting nonunion and delayed union could cause serious problems. This study sought to identify the nutrient arteries of the lesser metatarsals and to determine how osteotomy could injure these vessels.

Methods

Enhanced computed tomography scans of 21 ft (male, n = 10; female, n = 11; mean age 78.6 years at the time of death) were assessed. Twenty-one lower limbs in 21 cadaveric specimens were injected with barium via the external iliac artery, and the points at which the nutrient arteries entered the lesser metatarsals were identified on axial and coronal images.

Results

Each nutrient artery entered the lateral or medial plantar aspect of the lesser metatarsal in the middle third (just proximal to the middle point of the metatarsal) or proximal third obliquely from a distal direction. The mean ± standard deviation (SD) distances from the dorsal plane of the second, third, and fourth metatarsals to the point of entry of the nutrient artery in the axial plane were 8.2 ± 1.5, 7.6 ± 1.2, and 7.6 ± 1.5 mm, respectively. The mean ± SD distances from the distal epiphysis to the point of entry of the nutrient artery into the second, third, and fourth metatarsals in the coronal plane were 3.3 ± 1.1, 3.1 ± 1.0, and 2.8 ± 1.2 mm, respectively. The mean ± SD distances from the distal epiphysis to the point of entry of the nutrient artery into the second, third, and fourth metatarsals in the coronal plane were 46.0 ± 5.2, 40.9 ± 2.6, and 39.1 ± 3.7 mm, respectively. The mean ± SD distances from the proximal epiphysis to the entry point of the nutrient artery into the second, third, and fourth metatarsals in the coronal plane were 23.8 ± 4.7, 25.8 ± 4.3, and 25.0 ± 3.2 mm, respectively.

Conclusions

Distal metatarsal osteotomies might be safer than shaft or proximal osteotomy to avoid disruption of the nutrient artery, leading to delayed consolidation of the osteotomy and nonunion.