Summary Basilar Thumb Arthritis, also referred to as trapeziometacarpal (TMC) arthritis, is a common degenerative condition caused by attenuation of the volar beak and dorsoradial ligaments, leading to joint subluxation and cartilage degeneration of the trapeziometacarpal joint. This condition typically presents in elderly women with common symptoms of pain, crepitus, and loss of pinch/grip strength. Diagnosis is made clinically with tenderness to palpation over the thumb CMC joint, a painful CMC grind test, and radiographs of the hand showing osteoarthritis of the 1st CMC joint. Treatment can be conservative (therapybracing, injections) or operative, depending on the severity of symptoms and the stage of disease. Epidemiology Incidence common arthritis of the hand 2nd only to DIP arthritis login to view 1 more bullet Demographics more common in women seen in 25% of men and 40% of women aged > 75 years old however, radiographic evidence of TMC joint osteoarthritis is expected in normal aging among both sexes login to view 1 more bullet thumb CMC arthritis is more common in Caucasians hand OA is more common in native Americans than Caucasians/African Americans Risk factors female gender increasing age ligamentous laxity Ehler-Danlos syndrome theory currently not supported by experimental evidence Etiology Pathoanatomy theorized to be due to attenuation of anterior oblique ligament (Beak ligament) and dorsoradial ligaments leading to instability, dorsoradial subluxation, and arthritis of CMC joint Associated conditions MCP hyperextension deformity MCP arthritis concomitant carpal tunnel syndrome occurs in up to 50% Anatomy Osteology thumb carpal-metacarpal joint is a biconcave saddle joint consists of 4 articulations login to view 4 more bullets trapezium has a palmar groove for the flexor carpi radialis (FCR) tendon Ligaments anterior oblique (volar beak) ligament primary stabilizing static restraint to subluxation of CMC joint originates from the palmar tubercle of the trapezium and inserts on the articular margin of the ulnar metacarpal base dorsoradial ligament primary restraint to dorsal dislocation login to view 1 more bullet strongest and thickest ligament intermetacarpal ligament attaches from the radial base of the 2nd metacarpal to the ulnar base of the 1st metacarpal primary restraint to radial translation of the base of the 1st metacarpal login to view 1 more bullet posterior oblique ligament Biomechanics CMC joint reactive force is 13x applied pinch force Classification Eaton and Littler Classification of Basilar Thumb Arthritis Stage I Slight joint space widening (pre-arthritis) Stage II Slight narrowing of CMC joint with sclerosis, osteophytes <2mm Stage III Marked narrowing of CMC joint with sclerosis, osteophytes >2mm Stage IV Pantrapezial arthritis (STT involved) Presentation History progressive pain, crepitus, swelling to base of the thumb. Loss of pinch/grip strength symptoms exacerbated by activities such as opening jars or utilizing power grip Symptoms pain at base of thumb symptoms of concomitant carpal tunnel syndrome in approximately 50% of patients function difficulty pinching and grasping Physical exam inspection swelling and crepitus metacarpal adduction and web space contractures login to view 1 more bullet may have adjacent MCP fixed hyperextension (zig-zag or "Z" deformity) login to view 1 more bullet provocative tests painful CMC shear and grind tests login to view 2 more bullets tenderness to palpation directly over the thumb CMC joint Imaging Radiographs recommended views AP lateral Roberts view login to view 1 more bullet findings joint space narrowing osteophytes may show MCP hyperextension Differential Diagnosis C6 Radiculopathy pain radiating from neck, paresthesias to thumb and index finger De Quervains tenosynovitis positive Finkelstein's test STT arthritis TTP just proximal to TMC joint. May use imaging and diagnositic injections to differentiate source Scaphoid nonunion/SNAC evident on radiographs Radioscaphoid arthritis evident on radiographs Treatment Nonoperative NSAIDS, thumb bracing indications login to view 1 more bullet injections indications login to view 1 more bullet types login to view 4 more bullets Operative CMC arthroscopic debridement indications login to view 1 more bullet 1st metacarpal osteotomy indications login to view 1 more bullet contraindications login to view 2 more bullets technique login to view 1 more bullet trapeziectomy +/- ligament reconstruction indications login to view 1 more bullet multiple techniques with none showing clear benefit over the others login to view 9 more bullets CMC arthrodesis indications login to view 2 more bullets contraindications login to view 1 more bullet CMC denervation indications login to view 2 more bullets CMC prosthetic arthroplasty indications login to view 1 more bullet Techniques CMC Arthroscopic Debridement technique portals login to view 4 more bullets 1st Metacarpal Osteotomy technique redirects the force to the dorsal, more uninvolved portion of the 1st CMC joint perform closing dorsal wedge extension osteotomy fixation using K wires, intraosseous wiring, or plates outcomes gained in popularity 93% have symptom improvement at 7 years Trapeziectomy +/- Ligament Reconstruction technique many different surgical options are available login to view 4 more bullets complications injury to the radial artery during dorsoradial capsular dissection login to view 1 more bullet injury to the superficial radial nerve outcomes can expect ~25% subsidence postoperatively with no change in outcomes results in improved grip and pinch strengths CMC Arthrodesis technique CMC joint fused in login to view 3 more bullets outcomes good pain relief, stability, and length preservation decreased ROM, inability to put hand down flat nonunion rate of 12% CMC Denervation technique can be performed using 1 or 2 incisions login to view 4 more bullets resect 4 nerves login to view 4 more bullets complications specific to this treatment injury to the sensory brach of the radial nerve not all patients improve outcomes improved hand function, grip strength, and pain comparable results to trapeziectomy and CMC arthrodesis in terms of pain improved ROM compared to CMC arthrodesis CMC Prosthetic Arthroplasty technique several implant types exist login to view 1 more bullet complications specific to this treatment implant fracture or loosening subluxation silicone synovitis Complications 1st metacarpal subsidence and narrowing of trapezial space height occurs after trapeziectomy ± tendon suspension treatment LRTI with ECRL tendon or APL tendon login to view 1 more bullet MCP hyperextension deformity treatment depends on degree of hyperextension login to view 4 more bullets Prognosis Osteoarthritis in 1 joint in a row (proximal row) predicts for osteoarthritis in other joints in same row