There is no one answer to this question as it depends on the type and severity of the injury. Those who suffer from osteoarthritis or rheumatoid arthritis should keep a close eye on their body and on their loss of function as the disease progresses. Equipment may have to be repositioned and larger knobs and buttons may be required so that the diver can reach their equipment easily.
Injuries such as tendonitis, sprains, dislocations, and bursitis can all restrict movement and require rest and healing before diving. If a person experiences frequent dislocations, then scuba diving should be avoided.
Scoliosis, an extreme curvature of the spine, may require equipment adjustment. It should also be noted that those people with scoliosis may experience neurological abnormalities and exercise can cause back pain and muscle spasms.
Carpal tunnel syndrome is a situation in which the median nerve is mechanically trapped at the wrist. This can cause changes in sensation of the thumb and first two fingers and in severe cases can cause a weakened ability to grip objects. If this is your experience, then you should avoid diving.
A herniated disc is something that requires surgical treatment and diving should be avoided until post surgery and full healing. Divers should then return to diving only with a doctor’s permission.
Muscular dystrophy is a generalized weakness of the muscles and is caused by any one of a number of muscle diseases. Divers with muscular dystrophy may have trouble even getting in and out of the water and significant gear and equipment modification must be made. The disease is progressive and diving might become a therapeutic activity rather than a recreational one.