1st MTP Joint OA (Hallux Rigidus)

Patients present with dorsal 1st MTP joint pain, worse at extremes of dorsiflexion (push-off, squatting, kneeling, tiptoes, running, high heels). In early disease pain is mainly at end-range; in later disease pain occurs throughout range and at rest. Progressive stiffness limits push-off, stairs, running, and squatting; morning stiffness is typically less than 30 minutes. A visible and palpable dorsal prominence from the osteophyte is common, with shoe pressure complaints. Altered gait with compensatory lateral weight transfer may produce secondary transfer metatarsalgia under the 2nd and 3rd metatarsal heads.

Hallux rigidus is not the same as hallux valgus. Rigidus has a dorsal prominence with loss of dorsiflexion; valgus has a medial prominence (bunion) with lateral toe deviation. They can coexist but are separate conditions.

Examination:

• •Dorsal osteophyte: palpable bony prominence on the dorsum of the 1st MTP - often visible
• •Reduced dorsiflexion: assess active and passive 1st MTP dorsiflexion; normal approximately 65 to 75 degrees. Compare with the contralateral side
• •Pain on passive dorsiflexion: dorsal impingement against the osteophyte
• •Crepitus during motion indicates cartilage loss
• •Sesamoid tenderness: plantar 1st metatarsal head at the sesamoid complex
• •Hallux valgus assessment: check for lateral deviation (the two can coexist)
• •Gait: loss of push-off, lateral weight transfer, shortened stride
• •Transfer metatarsalgia: tenderness or callosities under the 2nd and 3rd metatarsal heads

Red flags: acute hot, swollen, erythematous 1st MTP (gout/podagra is the most important differential, and gout and OA can coexist; aspirate for crystal analysis if uncertain); bilateral symmetrical MTP involvement with prolonged morning stiffness and systemic features (inflammatory arthritis - rheumatology referral); rapidly progressive joint destruction; a young patient (under 45) with 1st MTP OA (lower threshold for imaging to exclude osteochondritis dissecans, osteochondral injury, sesamoid AVN, or inflammatory arthritis).

Per NICE NG226 principles, OA can often be diagnosed clinically in patients over 45 with activity-related pain and morning stiffness under 30 minutes. Because hallux rigidus often affects adults aged 30 to 60, patients under 45 have a lower threshold for imaging to exclude osteochondral lesions, trauma, or inflammatory arthritis. Weight-bearing radiographs are the preferred imaging test when indicated.

Plain radiographs: weight-bearing AP, lateral, and oblique views of the foot. The lateral view is the most useful for demonstrating the dorsal osteophyte (the hallmark finding) and assessing remaining joint space - both drive Coughlin-Shurnas grading. Look for joint space narrowing, subchondral sclerosis, subchondral cysts, loose bodies, sesamoid arthrosis, and periarticular erosions (if inflammatory arthritis is suspected).

USS can demonstrate effusion, synovitis, and dorsal osteophytes and is useful for differentiating OA from inflammatory synovitis. It can also guide injection. MRI is not routine for established hallux rigidus; consider it for suspected osteochondritis dissecans, early OA with normal X-ray, sesamoid AVN, or diagnostic uncertainty.

Bloods are not routine. Consider RF, anti-CCP, ESR and CRP if inflammatory arthritis is suspected; serum urate if gout is suspected. Joint aspiration with polarised light microscopy is the diagnostic standard if acute crystal arthropathy is suspected.

Management is stage-dependent. Conservative care is first-line for all grades and follows NICE NG226 principles.

Core NICE NG226 treatments are therapeutic exercise, weight management when appropriate, and information and support.

Conservative management (the foundation for all grades):

• •Footwear modification is the most important practical intervention: stiff-soled or rocker-bottom shoes reduce dorsiflexion demand at the 1st MTP during push-off; shoes with a wide, deep toe box accommodate the dorsal osteophyte. Avoid high heels
• •Orthotic devices for selected patients only - NICE NG226 does not recommend routine orthoses for all OA. A carbon fibre foot plate or Morton extension (a rigid insert under the great toe to limit dorsiflexion) may help selected patients
• •Activity modification: reduce activities requiring forced dorsiflexion. Cycling is well tolerated
• •Pharmacological per NICE NG226: consider topical NSAIDs (consider for non-knee joints). Oral NSAIDs if topical insufficient - short courses, lowest effective dose, gastroprotection. Do not routinely offer paracetamol, glucosamine, hyaluronan, or strong opioids
• •Intra-articular corticosteroid injection (USS-guided improves accuracy) for short-term symptom relief during flares or to support engagement with conservative management; also useful diagnostically

Surgical management when conservative care fails:

• •Joint-sparing procedures for Grade 1-2 disease (dorsal-predominant with preserved plantar cartilage): cheilectomy (dorsal osteophyte excision) is the standard joint-sparing procedure. Good results in Grade 1-2 disease. It does not cure the OA or stop progression - some patients eventually require arthrodesis - but it buys time while preserving motion. A Moberg dorsal closing wedge osteotomy of the proximal phalanx is sometimes combined with cheilectomy
• •Arthrodesis (1st MTP fusion) is the most established and reliable procedure for end-stage disease (Grade 3-4). The joint is fused in the optimal functional position of approximately 10 to 15 degrees dorsiflexion and 10 to 15 degrees valgus relative to the 1st metatarsal, eliminating motion and pain. Excellent pain relief, high fusion rates, high patient satisfaction. Complications include non-union (approximately 5 to 10 percent), hardware irritation, transfer metatarsalgia, and IP joint OA (the interphalangeal joint compensates and may degenerate over time)
• •1st MTP joint replacement (arthroplasty) is a selective option that aims to preserve motion. It is less established and less predictable than fusion. BOFAS registry data showed stronger 12-month improvements after fusion and cheilectomy than after arthroplasty

Refer to FCP, advanced practice physiotherapist, or community MSK assessment for structured conservative management before secondary care referral. Refer to orthopaedic foot and ankle or podiatric surgery if conservative care fails or surgical options are being considered. Refer to rheumatology if inflammatory arthritis is suspected. Always exclude gout before attributing symptoms to OA.

Rehabilitation for hallux rigidus is primarily footwear, orthotic, and activity modification based, with therapeutic exercise as the NICE NG226 core recommendation for all OA.

• •Phase 1 (symptom management): footwear modification (stiff-soled or rocker-bottom shoes, wide and deep toe box) is the priority. Carbon fibre plate or Morton extension for selected patients. Topical or oral NSAIDs for flares. Gentle 1st MTP range-of-motion exercises within comfortable range. Calf strengthening for gait efficiency. Intrinsic foot strengthening (short-foot exercise). Cycling for aerobic fitness
• •Phase 2 (functional optimisation): maintain available range. Continue strengthening. Address compensatory transfer metatarsalgia (metatarsal pad, forefoot cushioning). Hip and core strengthening because altered gait mechanics increase proximal demands. Balance and proprioception. Weight management if appropriate
• •Phase 3 (ongoing maintenance): continue footwear modifications permanently. Ongoing strengthening. Activity modification as a lifestyle strategy. Podiatry input for orthoses and callus management

Post-cheilectomy rehabilitation: 0 to 2 weeks dressing, protected weight-bearing in a stiff-soled post-operative shoe, elevation, and gentle active range of motion - the priority is to regain the dorsiflexion freed by osteophyte removal before scar tissue restricts it. 2 to 6 weeks progressive weight-bearing and progressive strengthening. 6 to 12 weeks normal footwear, full weight-bearing, return to sport typically 8 to 12 weeks. Early range of motion is the key to success.

Post-arthrodesis rehabilitation: 0 to 6 weeks non-weight-bearing or protected weight-bearing (surgeon-dependent), elevation, wound care. 6 to 12 weeks progressive weight-bearing and transition to stiff-soled shoes (often with rocker modification). From 12 weeks full weight-bearing in supportive shoes; rocker-bottom shoes are often needed long-term. Counsel that fusion eliminates 1st MTP motion - high heels are not possible and sprinting and squatting are limited, but comfortable walking, hiking, cycling, and many sports are achievable.

• •NICE NG226 - therapeutic exercise is the most important core treatment; consider topical NSAIDs for non-knee joints; do not routinely offer paracetamol, glucosamine, hyaluronan, or strong opioids; orthoses are for selected patients only.
• •Coughlin and Shurnas classification (FAI 2003) - the standard 5-grade radiographic and clinical classification driving the cheilectomy versus arthrodesis decision.
• •BOFAS guidance - 1st MTP arthrodesis is the most established procedure for end-stage hallux rigidus; the functional fusion position is approximately 10 to 15 degrees dorsiflexion and 10 to 15 degrees valgus.
• •BOFAS UK registry - fusion and cheilectomy gave stronger 12-month improvements than 1st MTP arthroplasty cohorts.
• •BOFAS Big Toe Arthritis Hyperbook - clinical pathway distinguishing dorsal-predominant disease (cheilectomy candidate) from global joint space loss (arthrodesis).

• •Hallux rigidus is the most common site of OA in the foot and is commonly primary (idiopathic), unlike ankle OA which is predominantly post-traumatic.
• •The dorsal osteophyte is the hallmark, best seen on the lateral weight-bearing X-ray. Cartilage loss begins dorsally; preserved plantar cartilage (Grade 1-2) means cheilectomy may succeed, while global narrowing (Grade 3-4) means arthrodesis is most reliable.
• •Normal 1st MTP dorsiflexion of approximately 65 to 75 degrees is essential for the windlass mechanism and push-off. Loss drives compensatory lateral transfer metatarsalgia.
• •Hallux rigidus is not the same as hallux valgus: rigidus is dorsal prominence with loss of dorsiflexion; valgus is medial prominence with lateral toe deviation. They can coexist.
• •Gout (podagra) is the most important acute differential and can coexist with OA. Aspiration with crystal analysis is the diagnostic standard.
• •Arthrodesis is fused in approximately 10 to 15 degrees dorsiflexion and 10 to 15 degrees valgus; IP joint OA is a recognised long-term consequence. NICE NG226: consider topical NSAIDs for non-knee joints; do not routinely offer paracetamol, glucosamine, hyaluronan, or strong opioids.