summary Hallux rigidus is a common foot condition characterized by pain and loss of motion of the 1st MTP joint in adults due to degenerative arthritis. Diagnosis is made with orthogonal radiographs of the foot that may show joint space narrowing and dorsal osteophytes of the 1st MTP joint. Treatment of early disease consists of a trial of nonoperative management with a Morton's extension orthotic. Operative management is indicated for higher grade disease and varies depending on chronicity of symptoms and severity of osteoarthritis. Epidemiology Incidence 2.5% of patients older than 50 years most common location of osteoarthritis in the foot Demographics females > males (2:1) most commonly noted in the 5th and 6th decade of life Risk factors history of trauma to the 1st MTP joint noted in ~80% of patients with unilateral disease high impact sports Etiology Pathophysiology primary etiology unknown acute trauma and repetitive microtrauma predispose to arthritic changes pathoanatomy osteophyte formation and degeneration of the cartilage occur dorsally in early stages and progress to involve the entire joint anatomic variations of first metatarsal may play a role in arthritic predisposition metatarsus adductus metatarsal head morphology long first metatarsal hallux valgus or hallux varus Associated conditions orthopedic conditions sesamoid arthritis medical conditions gout rheumatoid arthritis seronegative arthropathies Anatomy Osteology first metatarsal shortest and widest Neurovascular medial branch of the medial dorsal cutaneous nerve overlies 1st MTP joint can become irritated by dorsal osteophytes plantarmedial hallucal nerve also supplies the MTP articulation Biomechanics the first MTPJ carries up to ~120% of an individual's body weight with each step Classification Coughlin and Shurnas Classification Exam findings Radiographic findings Grade 0 Stiffness Dorsiflexion of 40-60 degrees (loss of 10-20%) Normal Grade 1 Mild pain at extremes of motion Dorsiflexion of 30-40 degrees (20-50% lost) Mild dorsal osteophyte, normal joint space Grade 2 Moderate pain at extremes of motion, increasingly more constant Dorsiflexion of 10-30 degrees (50-75% lost) Moderate dorsal osteophyte,<50% joint space narrowing Grade 3 Significant stiffness, near constant pain, pain at extreme ROM, no pain at mid-range Dorsiflexion of 10 degrees or less (75-100% lost) Severe dorsal osteophyte, >50% joint space narrowing Grade 4 Significant stiffness, pain at extreme ROM, pain at mid-range of motion Dorsiflexion same as Grade 3 Same as grade III Presentation History pain swelling gait abnormalities difficulty with shoe wear Symptoms first ray and 1st MTP joint pain worse with push off or lift-off phase of gait dorsal medial foot paresthesia due to dorsal osteophytes and compression of medial dorsal cutaneous nerve transfer metatarsalgia Physical exam inspection swelling of the 1st MTP joint dorsal prominence over the 1st MTP joint (due to dorsal osteophytes) severe disease may present with hyperextension deformity skin irritation and redness from shoe wear motion limited dorsiflexion pain with terminal dorsiflexion as disease progresses, patient develops pain throughout arc of motion inverted gait neurovascular decreased push-off strength decreased sensation over distal aspect of medial dorsal foot may have tinel sign provocative tests TTP over the first MTP pain with grind test indicative of severe disease with central chondral wear Imaging Radiographs recommended views weight-bearing AP, lateral, sesamoid and oblique views of the foot findings dorsal osteophytes joint space narrowing subchondral sclerosis and cysts MRI indications rarely needed suspected osteochondral lesion with normal radiographs can better characterize mild osteoarthritis findings osteochondral lesions Treatment Nonoperative NSAIDS, activity modification, intra-articular injections & Morton's extension orthotic indications grade 0 and 1 disease outcomes good short and mid-term pain relief noted in low-grade disease up to 55% treated successfully without surgery Operative dorsal cheilectomy indications grade 1 and 2 disease select patients with grade 3 disease with primarily pain with terminal dorsiflexion shoe wear irritation from dorsal prominence and pain (ideal candidate) contraindications when pain located in the mid-range of the joint during passive motion positive grind test patients with sesamoid arthritis medical comorbidities precluding surgery (poorly controlled diabetes, vascular disease) outcomes pain with terminal dorsiflexion is an indicator of good results with dorsal cheilectomy Grade 1 and 2: up to 97% excellent results with 92% with pain relief at 10 years At higher grades, 25-56% require conversion to arthrodesis Osteotomy (e.g. Moberg procedure) indications runners with reduced dorsiflexion (60° is needed to run) failure of cheilectomy to provide at least 30 to 40 degrees of motion technique dorsal closing wedge osteotomy of the proximal phalanx outcomes 88% satisfaction in patients treated with combined cheilectomy and osteotomy at 2 years follow-up limited literature on outcomes of osteotomy alone Resection arthroplasty (Keller procedure) indications elderly, low demand patients with significant joint degeneration and loss of motion that allows for rapid rehabilitation contraindications patients with pre-existing rigid hyperextension deformity of 1st MTP joint patients with sesamoid arthritis outcomes good results have been noted in low demand elderly patients when coupled with interposition arthroplasty, up to 90% with improvement in pain and only 4% requiring additional surgery at 4.5 years follow-up significant risk of joint instability for younger and more active patients Prosthetic Arthroplasty indications grade 3 and 4 disease for patients who wish to preserve joint motion contraindications active infection insufficient bone stock hallux sesamoid arthritis technique may be hemiarthroplasty or total joint arthroplasty outcomes silicone implants may have a good short-term satisfaction rate but have high long-term failure rate osteolysis and synovitis cause mid to long-term pain and joint destruction largely abandoned current implant designs with 80-90% survival rates at ~5 years no difference in functional outcomes, complications or satisfaction rates between hemiarthroplasty and total joint arthroplasty mid-term and long-term results demonstrated loosening and need for complex revisions due to bone loss worse long-term outcomes than primary fusion arthroplasties requiring secondary fusions have worse outcomes than primary fusion Arthrodesis indications standard of care grade 3 and 4 disease (significant joint arthritis) most common procedure for hallux rigidus procedure MTP joint arthrodesis with structural bone graft indications for structural bone graft 1st MT shortening that cannot be adequately rebalanced with a lesser metatarsal osteotomy (usually shortening > 5 mm) most commonly seen with failed MTP arthroplasty significant proximal phalanx bone loss with inadequate remaining bone for fixation without compromising IP joint, 1st MT shortening with loss of medial support of the 2nd toe predisposing to varus at the 2nd MTP joint. outcomes 90-100% fusion rate 95% satisfaction rate high rate of return to hiking (92%), golf (80%), jogging (75%), tennis (75%) Techniques NSAIDS, activity modification, intra-articular injections & Morton's extension orthotic activity modifications avoid activities that lead to excessive great toe dorsiflexion intra-articular injections both corticosteroid and sodium hyaluronate injections have been shown to significantly improve pain scores at 4 and 8 week follow-up in low-grade disease types of orthotics Morton's extension with stiff foot plate is the mainstay of treatment extends past the first MTP joint providing a stiff construct that allows minimal dorsiflexion at the articular surface stiff sole shoe and shoe box stretching may also be used Dorsal cheilectomy technique dorsal approach with complete synovectomy remove up to 30% of the dorsal aspect of the metatarsal head along with dorsal osteophyte resection resection > 30% may lead to joint subluxation the goal of surgery is to obtain 70-90% of dorsiflexion intraoperatively Dorsal closing wedge osteotomy of the proximal phalanx (Moberg procedure) technique increases dorsiflexion by decreasing the plantar flexion arc of motion may be performed with cheilectomy to increase dorsiflexion Resection arthroplasty (Keller Procedure) technique involves removing the base of the first proximal phalanx interposition risk of hyperextension (cock-up deformity), weakness with push-off, and transfer metatarsalgia (decreased with capsular interposition) Prosthetic arthroplasty technique hemiarthroplasty unipolar implant designed to replace the articular surface of metatarsal head or proximal phalanx base benefits compared to total joint maintains length of first ray easier conversion to arthrodesis if necessary total joint arthroplasty first and 2nd generation silastic implants (silicone rubber) high failure rate (~60%) with silicone wear, osteolysis and implant failure third generation metal implants with press-fit fixation fourth generation metal implants with threaded stem fixation Arthrodesis technique compression and internal fixation can be achieved with wires, pins, lag screws, dual crossed screws and plates dorsal plate with compression screw is biomechanically strongest construct preferred surgical alignment 5 degrees of valgus in relation to the metatarsal shaft 15 degrees of dorsiflexion in relation to the floor best way to assess this intraoperatively is with foot plate to simulate weight bearing with 4-8mm of clearance of toe from plate structural bone grafting technique structural bone graft used to restore metatarsal length tricortical iliac crest allograft most commonly used complications fusion in excessive dorsiflexion causes pain at tip of the toe, over the IP joint, and under the 1st metatarsal with excessive dorsiflexion fusion in excessive plantar flexion causes increased pressure at the tip of the toe fusion in excessive valgus increases the risk of IP joint degeneration Complications Progression of arthritis may occur after cheilectomy conversion to arthrodesis needed in 7-9% of patients within 10 years Failed arthroplasty risk factors early generation implants (especially silicone implants) silicone implants have been abandoned other designs have failed due to loosening, osteolysis, technical errors, and persistent pain treatment implant resection, synovectomy if there is isolated great toe pain implant resection, bone grafting, and arthrodesis if there is great toe pain with lesser toe metatarsalgia Malunion incidence 16% after arthrodesis may lead to transfer metatarsalgia arthritis of the hallux interphalangeal joint and difficulty with push off Nonunion incidence 5-10% after arthrodesis < 40% of patients with a nonunion are symptomatic treatment revision arthrodesis with bone grafting First MTP joint cock-up deformity risk factors keller resection arthroplasty treatment first MTP joint arthrodesis Hallux IP joint osteoarthritis incidence 15% of patients following hallux MTP joint arthrodesis risk factors hallux MTP joint arthrodesis treatment usually asymptomatic Symptomatic hardware Instability may occur after excessive resection during a cheilectomy Infection < 2% of cases Prognosis Natural history of disease radiographic progression may not always correlate with symptom progression Return to activity after arthrodesis 96% patient satisfaction rate with respect to post-operative activity level high rate of return to hiking (92%), golf (80%), jogging (75%), tennis (75%)