Clinical and Radiologic Outcome of First Metatarsophalangeal Joint Arthrodesis Using a Human Allogeneic Cortical Bone Screw

Abstract

Background: Different fixation techniques are established for first metatarsophalangeal joint (MTPJ) arthrodesis, including compression screws, plates, Kirschner wires, metal- and bioabsorbable screws as well as staples. The purpose of this study was to investigate and present first clinical and radiologic results using a novel human, allogeneic cortical bone screw for arthrodesis of the first MTPJ.

Methods: Arthrodesis of the first MTPJ was performed in 31 patients with hallux rigidus. Percentage union and time to union were the first outcomes; visual analog scale for pain, hallux valgus angle (HVA), intermetatarsal angle, and American Orthopaedic Foot & Ankle Society (AOFAS) hallux score were secondary outcomes.

Results: Median time to union was 89 days, and union was observed in all patients. There were 4 complications (2 osteolysis margin, 1 cystic brightening, and 1 severe swelling at the first follow-up) all of that resolved at last follow-up. Pain significantly decreased from visual analog scale 8.0 to 0.2 points (P < .0001). The HVA decreased from 30.4 to 10.2 degrees in the patient group with deformities. The total AOFAS score increased significantly from 48 to 87 (P < .0001).

Conclusion: Primary and revision arthrodesis of hallux rigidus with the human, allogeneic cortical bone screw reveals satisfying results similar to clinical and radiologic outcomes of other surgical techniques. Within 1 year, the human, allogeneic cortical bone screw is fully remodeled to host bone.

Level of evidence: Level IV, retrospective case series without control group.

Keywords: Shark Screw®; allogeneic; allograft; arthrodesis; bone union; cortical bone screw; first metatarsophalangeal joint; hallux rigidus; human.

Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. ICMJE forms for all authors are available online.

© The Author(s) 2022.

Figures

Figure 1.

Surgical procedure (2 crossed Shark Screws®): (A) Lateral view; starting from an imaginary center line, the Kirschner wires were placed once dorsally and once plantarly so that they did not touch each other. This leaves enough space for drilling, tapping, and placing the Shark Screws®. (B) Anteroposterior view: a 1.6-mm Kirschner wire was placed from proximal medial to distal lateral, dorsal, and a second Kirschner wire from distal medial to proximal lateral, plantar. (C) Lateral and (D) anteroposterior views: these correspond to the later desired position of the Shark Screw®. The Shark Screws® were screwed in without much resistance. (E) Lateral view: protruding material was sawn off at the bone level. The transplant was smoothened and functions as a bone bridge and guiding substance for host cell migration. (F) Postsurgical plaster.

Figure 2.

AOFAS hallux score subgroups: pain, function, axial position, and AOFAS total. The maximal achieved scores after surgery are 35 for function and 90 for AOFAS total, because of arthrodesis of the first metatarsophalangeal joint. AOFAS, American Orthopaedic Foot & Ankle Society.

Figure 3.

A hallux rigidus patient without deformities treated with 2 crossed Shark Screws® using the cup and cone technique: (A) presurgery and (B) 6 weeks, (C) 4 months, (D) 7 months, and (E) 12 months postsurgery. The integration of the crossed human. allogeneic cortical bone screws is well visible; after 12 months, only a faint line of the human, allogeneic cortical bone screw is visible.

Figure 4.

Hallux rigidus patient treated with 1 intramedullary Shark Screw® (5 × 35 mm) using the cup and cone technique for first metatarsophalangeal arthrodesis additional to second-fourth Weil osteotomies and second proximal interphalangeal arthrodesis with Shark Screw® at 3.5 mm: (A) presurgery, (B) just after surgery, and (C) 3 months and (D) 6 months postsurgery; the screws are already well integrated into the bone.

Figure 5.

Clinical results of the diabetic patient treated with antibiotic therapy and arthrodesis after refreshing the surfaces of the joint of the hallux rigidus at the same time: (A) 1 week after surgery, (B) 2 weeks after surgery, (C) 6 weeks after surgery, and (D) 10 weeks after surgery; the ulceration was completely healed.

Figure 6.

Radiologic results of the diabetic patient in whom union was observed 160 days after surgery: (A) presurgery, (B) postsurgery, (C) 6 weeks postsurgery, (D) 12 months postsurgery, and (E) 20 months postsurgery; the human, allogeneic cortical bone screws are nearly invisible.

Figure 7.

Bone density (optical density [counts]) was evaluated radiographically for the human, allogeneic cortical bone screw in the host bone and of the host bone around the screw. Average time points of evaluation was just after surgery and at 4, 8, and 17 months after surgery. *P < .05 and **P < .01 vs postsurgical values; ****P < .0001 vs the density of the host bone just after surgery.