Dr Paul Hatfield of Maritzburg Orthopaedic Centre explains osteoarthritis of the base of the thumb – including symptoms, diagnosis and treatment.
Degenerative wear of the articular cartilage of the carpo-metacarpal joint of the thumb is a common condition in people over the age of 50 years. This joint, with its wide range of movement, is held in position by several strong ligaments. When these ligaments stretch with increasing age, significant irreversible wear of the joint surface occurs. Women are three times more likely than men to develop thumb arthritis due to hormone-associated increased joint laxity.
Pain, stiffness and weakened grip strength are the principle presenting complaints. The pain is described as a constant dull ache in the palmar aspect at the base of the thumb. A severe sharp activity-related pain is also common, and can restrict day-to-day activities such as opening jars and gripping objects. With time, a prominent bony lump is seen and felt as the joint slowly begins to dislocate. A contracture forms making it difficult to move the thumb away from the palm, and potentially limiting hand function and grip strength. Further deformities of the thumb may develop.
The diagnosis is made after taking a history as well as carrying out a thorough clinical examination. An X-ray will confirm the diagnosis, but decisions of the type of management depend on whether the thumb arthritis is restricting daily activities or if regular pain killers and anti-inflammatory meds are required to control the pain.
Treatment aims to relieve pain, restore function and prevent deformity. Non-surgical treatment begins with the occasional use of anti-inflammatory medications (Voltaren and Celebrex), reducing aggravating activities if possible and wearing a supportive thumb brace to stabilise the degenerative joint will decrease pain and slow progression of the arthritis. A hand therapist can help with the splint as well as with a stretching and strengthening programme. A cortisone injection into the joint can help to relieve pain but this usually only lasts for a period of weeks or months.
Surgery is indicated when regular medication is required to control the pain and daily activities are significantly curtailed. As with all osteoarthritic joints, surgical options include joint fusion (the result is a strong joint but restricted motion), artificial joint replacement (potentially very effective but high complication rates) or resection/excision arthroplasty.
Excision arthroplasty is the gold standard, most reliable and effective method to reduce pain and restore function. It involves excising the trapezium bone which makes up one half of the arthritic joint surface. The thumb is then stabilised reconstructing a ligament as well as a tendon sling and placing a bunched up tendon into the gap to act as a buffer (tendon interposition).
Rehabilitation following this surgery involves the use of a slab and splint for a period of eight weeks post-operatively to stabilise the joint. A hand therapist will make and fit the splint and will supervise an exercise programme focusing on regaining mobility, pinch strength and dexterity in order to regain hand function.
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Dr Paul Hatfield returned to his hometown of Pietermaritzburg after completing his medical studies at the University of Cape Town. He continued his studies at the Nelson Mandela School of Medicine in Durban, where he qualified as an Orthopaedic Surgeon. Back in Pietermaritzburg, he gained valuable experience at Edendale Hospital before completing a Hand Fellowship with Prof Mike Solomons at the University of Cape Town. Paul is married, has two daughters and enjoys competing in Maritzburg’s iconic sports of paddling, running and cycling.