Controversy still exist about the treatment of high grades hallux rigidus. Arthrodesis of the first MTP joint which is the main stay treatment of advanced hallux rigidus has its own problems and limitations. Loss of motion and exertional pain is not favored by a lot of patients apart from the delay in return to daily activities for at least 2 or 3 months till complete union of the arthrodesis 9.Furthermore, the complications which accompanied implant arthroplasty of the first MTP joint together with technical difficulties and high costs make this treatment modality not popular. Keller resection arthroplasty with removal of only the proximal one-fourth of the proximal phalanx and detachment of the plantar plate from the base of the proximal phalanx offered an alternative simple procedure with improvement of range of motion. Metatarsalgia however developed in many patients due to shortening of the first ray.

Mroczek and Miller described their modification of the original Keller procedure, which consisted of an oblique resection of the articular surface of the phalanx, thereby maintaining the plantar plate attachment to the proximal phalanx and avoid shortening of the first ray 11.  The current study showed the results of modified oblique Keller interposition arthroplasty as a treatment modality which avoid replacement arthroplasty complications and arthrodesis limitations. The procedure should be considered as a joint reconstructive procedure, because it preserves the first MTP joint plantar flexion and enhances first MTP joint dorsiflexion without shortening either the proximal phalanx or the first metatarsal. The study included 20 patients with advanced hallux rigidus (8 grade 3 and 12 grade 4).

At final follow up, significant improvement in pain VAS, dorsiflexion range, and AOFAS score was achieved in all patients.  Various interpositional arthroplasties with either allografts 12 (regenerative tissue matrix, consisting of collagen and extracellular protein matrices created from human cadaver tissue) or autograft (dorsal capsular 11,13, medial capsular 14, extensor halluces longus 15, free plantaris 16 or gracilis tendons 6,17) have been described. All have shown increase in range of motion (table 1) as well as outcome score (table2) comparable to those obtained in the current study.