Hallux Rigidus

Hallux rigidus is osteoarthritis of the first metatarsophalangeal joint, with loss of dorsiflexion, dorsal osteophytes and articular cartilage loss. It affects about 2.5% of adults over 50, and is more common in women. It is the most common arthritis of the foot.

Causes:

• Previous trauma or turf toe
• Long or elevated first metatarsal
• Hallux valgus interphalangeus
• Repetitive stress in dancers and athletes
• Inflammatory arthropathy, gout and genetic predisposition

Grading by radiographic and clinical findings: grade 0 stiff with normal radiographs, grade 1 mild dorsal osteophyte with preserved joint space, grade 2 moderate joint space narrowing and flattening, grade 3 severe narrowing with a marked osteophyte and sesamoid involvement, grade 4 loss of joint space with loose bodies and pain throughout motion. The dorsal osteophyte limits dorsiflexion needed for toe off, which shifts load to the lateral foot.

• Pain at the base of the great toe on walking, especially push off and stairs, stiffness, and swelling
• A dorsal bump that irritates in shoes, and reduced dorsiflexion (normally 60 to 70 degrees)
• A positive grind test (pain with axial load and rotation), pain at the extremes of motion
• An antalgic gait with weight on the lateral border, and secondary interphalangeal hyperextension
• Red flags: acute swelling and erythema (gout, septic arthritis), night pain, and rapid progression

• Clinical diagnosis from range of motion and the grind test.
• Weight bearing radiographs (anteroposterior, lateral, oblique): joint narrowing, dorsal and lateral osteophytes, subchondral sclerosis, cysts and sesamoid changes.
• Serum urate, ESR and CRP or joint aspiration when synovitis is acute.
• MRI only when other pathology is suspected.

Differentials: hallux valgus, gout, turf toe, sesamoiditis, septic arthritis, rheumatoid arthritis, osteochondritis.

Conservative (grades 0 to 2, and most grade 3):

• Stiff soled or rocker bottom shoes with a Morton extension orthosis to limit motion.
• Paracetamol 1 g orally every 6 hours, ibuprofen 400 mg orally every 8 hours with food for up to 7 days, or topical diclofenac 1% gel 4 g three times daily.
• Intra articular injection: triamcinolone acetonide 10 mg with lidocaine 1% 0.5 mL under image guidance. Hyaluronic acid 1 mL weekly for 3 weeks is an alternative.

Surgery:

• Grades 1 and 2: cheilectomy, removing the dorsal 25 to 30% of the metatarsal head with the dorsal osteophyte, with or without a Moberg dorsiflexion osteotomy of the proximal phalanx.
• Grades 3 and 4: arthrodesis of the first metatarsophalangeal joint, fused in 10 to 15 degrees of dorsiflexion relative to the floor and 10 to 15 degrees of valgus, with a dorsal plate and a compression screw. Union rate about 90 to 95%.
• Interposition arthroplasty or hemiarthroplasty in selected low demand patients.
• Cefazolin 2 g IV before incision.
• Postoperative: a stiff soled shoe, heel weight bearing for 4 to 6 weeks after arthrodesis (immediate motion after cheilectomy).

Complications: recurrent osteophyte, nonunion and malunion, transfer metatarsalgia, infection, interphalangeal joint arthritis.

Follow up at 2 weeks, 6 weeks and 3 months. Counsel on footwear and activity modification.