Total hip joint replacement is a very successful operation for hip arthritis secondary to degeneration of the cartilage due to osteoarthritis, rheumatoid arthritis or rarer conditions such as avascular necrosis and trauma. It is increasingly performed through smaller incisions, where appropriate, which can speed recovery. In order to prolong the lifespan of the commonly used prostheses, different bearing surfaces can be used for younger patients rather than the traditional metal head & polyethylene liner. These are metal on metal bearings (as used in hip resurfacing) or ceramic on ceramic. These produce less wear particles, thereby reducing the risk of loosening of the prosthesis in the long term. Total knee joint replacement is a very successful operation for treatment of knee arthritis secondary to cartilage degeneration from trauma, osteoarthritis and rheumatoid arthritis. In addition to resurfacing the degenerate compartments, it corrects the varus or valgus alignment of the limb so that the weight bearing axis passes from the centre of the hip to the centre of the ankle through the centre of the knee replacement at the end of the procedure, prolonging the life of the implant. The alignment is corrected by the use of the bone cuts and the accuracy of the bone cuts is increased with Computer Navigation. This also enables the surgeon to check the accuracy of the cuts after they are made which isn't possible with the traditional jigs. Unicompartment knee replacement is used to replace the degenerate compartment only (usually medial) in patients with less deformity and less severe changes, which has the advantage of a smaller incision, quicker recovery and usually better postoperative flexion. It also enables easier revision if this is required in the future. Total ankle joint replacement is indicated in selected patients with ankle arthritis who do not have significant deformity and if there is evidence of arthritis elsewhere in the foot such as the subtalar joint. This therefore avoids stressing these arthritic joints more which would occur with stiffening of the ankle with a fusion.

Osteotomy is surgically cutting a bone and resetting it. The new position is held with a rod or a plate and screws. It is performed to correct deformity (often post fracture) or in the knee in younger patients to unload an arthritic compartment in the knee - transferring the weight through the compartment not affected by arthritis.

Over the last 30 years a large number of orthopaedic procedures on joints have been performed using an arthroscope, where a fibre optic telescope is used to look inside the joint. Through this type of keyhole surgery, fine instruments can be introduced through small incisions (portals) to allow surgery to be performed without the need for large cuts. This allows many procedures to be performed as a day stay and allows quicker return to normal function of the joint. Arthroscopic surgery is less painful than open surgery and decreases the risk of healing problems. Arthroscopy allows access to parts of the joints which cannot be accessed by other types of surgery.

Sporting injuries and trauma can cause injuries to the ligaments of the knee MCL, ACL, PCL and LCL. ACL rupture is a common injury in contact and non contact sports. It is often associated with a meniscal tear. With ongoing instability or in someone who is active and wishes to continue to participate in sports, an ACL reconstruction is a successful operation. This can be done arthroscopically, enabling a quicker recovery. MCL injuries are invariably treated non operatively, enabling a return to sport in approximately 4-6 weeks. A medial meniscal tear can be mistaken for an MCL injury. PCL injuries are less common and, depending on severity, are usually treated non operatively. LCL injuries should usually all be repaired acutely, especially if associated with a PCL rupture. Ankle sprains invariably heal with immobilisation and physiotherapy. Symptomatic ongoing instability with recurrent sprains may require ankle stabilisation.