What is it Basal thumb arthritis is the second most common hand joint affected by arthritis. The CMC joint is a uniquely structured biconcave-convex saddle joint in comparison to the hinge-type joints that dominate the hand. It consists of four articulations: trapeziometacarpal (TM), trapeziotrapezoid (TT), scaphotrapezial (ST) and trapezium-index metacarpal (TIM) articulations. Diagnosis Diagnosis is based on clinical findings such as pain, dropping objects, oedema, instability, limited range of motion, and joint deformities. Typical patients include postmenopausal women with disabling pain at the thumb base, often radiating to the thenar eminence or MCP joint, men with a history of repetitive occupational joint use or trauma and young women with generalised ligamentous laxity and joint hypermobility. Examination Tender over CMCJ or STT joint pain on ballotment +ve grind test - axial compression rotation test X-rays are diagnostic. If during a thimb pinch manouvre there is significant hyperextension this suggests the joint has subluxed somewhat and this would suggest surgical options are required. Management Non-surgical treatment The first line of treatment of TMJ osteoarthritis is nonsurgical and includes rest, splinting, anti-inflammatory drugs, steroid injections, physiotherapy, and patient education, usually offered on a 3-month trial. (i) Splintage and hand therapy As heavy stresses are placed on the TMJ, particularly during pinching or grasping, splintage can be useful. A variety of thermoplastic splinting options exist; from a small short opponens splint which supports the TMJ and MCP joint, to a much larger long opponens splint, which includes both the MCP joint and the wrist. Hand therapists may be able to provide advice on avoiding activities that may lead to thumb metacarpal adduction and on maintaining the first web space and strengthening the thenar muscles. (ii) Steroid Injections Steroid injection this is best done guided unless you are very experienced, the best way to use a steroid injection is in early stage 1 + 2 disease where there has been little subluxation of the joint. After the injection ideally follow up with 30 days of splinting in the joint. Up to 18 months pain relief can be obtained in this way. Repeated steroid injections are less valuable as these can lead to laxity of the capsule and increase the risk of subluxation of the joint. (iii) Adaptations Education about techniques of joint protection can assist in controlling symptoms and delay the need for surgical intervention. These may include use of assistive devices (e.g., tap turners), use of splints or instruction in ways to change their technique for performance of specific tasks (e.g., lifting with two hands). Staging as described by Eaton and Glickel and Surgical Management I Normal articular contours; joint space may be widened due to effusion or ligamentous laxity. II Joint space is slightly narrowed but articular contours maintained and there is minimal sclerosis of the subchondral bone. Joint debris and osteophytes < 2mm. ST joint is normal. III Markedly narrowed or obliterated joint space with cystic changes, sclerotic bone, and osteophytes > 2mm in size. Varying degrees of subluxation, and the ST joint not affected. IV Complete obliteration of the joint space with signs of pantrapezial arthritis. Large osteophytes with marked subchondral sclerosis are present along with osteoarthritic changes of the ST joint. Surgery If patients have failed conservative management and have pain and poor function surgery is indicated. There are several options to consider and these will be discussed after fully evauating the functional and radiological appearances. Options include Ligament reconstructions Trapezial resection procedures Implant arthroplasty Metacarpal Osteotomy Arthrodesis.

STT (scaphotrapezotrapezoidal) joint arthritis

Degenerative arthritis of the STT (scaphotrapezotrapezoidal) joint of the thumb commonly develops as a result of normal use and the natural aging process. Nonoperative treatment options include rest, splinting, therapy, oral anti-inflammatory medication, and intraarticular steroid injection. Pain and progressive loss of motion may occur with conservative management due to progressive arthritis. Progressive joint deterioration may occur. Surgical options include either joint fusion or arthroplasty. Total joint reconstruction requires trapeziectomy and soft tissue reconstruction, and often involves partial trapezoid excision and debridement of the index metacarpal base. Fusion may require bone graft, and often results in enough loss of mobility of the thumb that the palm cannot be placed in full contact with a flat surface. Surgery has the risks of persistent soreness, painful neuroma, instability of the thumb, weakness and numbness. Postoperative immobilization and therapy is essential. Surgery usually requires approximately three months for recovery and soreness may persist for a year after successful surgery. An average of one out of three patients will have some degree of persistent pain, deformity or weakness despite surgery.