Surgical intervention for OA has traditionally been advocated after medical therapy has failed. Surgeons involved in musculoskeletal trauma must be meticulous with regard to reconstituting the disrupted joint surfaces of intraar-ticular fractures. Residual joint incongruity has been correlated with early posttraumatic arthritis and a poor clinical outcome. Some articular fractures injure cartilage so severely that the joint will degenerate even with an accurate articular reduction. The late development of OA may be due to chondrocyte apoptosis resulting from the initial impact . Late development OA seems to proceed regardless of the quality of the articular reconstruction. Patient-to-patient variability is wide with respect to the sensitivity of joints to an insult.
In common with many elective surgical interventions, a stepwise approach is often employed in the treatment of OA. The procedures are site specific and in the first instance often involve a combined diagnostic/therapeutic joint injection. In the hip, a radiolucent dye is injected into the hip joint under fluoroscopic guidance to confirm successful needle position. A mixture made up of a local anesthetic and a steroid is then injected. If the pain is truly due to isolated hip disease, the patient will be free of pain in minutes, due to the local anesthetic effect, with the steroid component producing symptomatic relief often over several months.
Other procedures include arthroscopic joint debridement and washout. This procedure is successful in many patients with mechanical symptoms such as locking of the joint or the joint giving way because of the presence of osteophytes and loose bodies. These can be readily removed; the degenerate articular cartilage is then shaved or otherwise ablated to restore a stable surface.
Osteotomy, with correction of bony malalign-ment, is used as a prophylactic measure in the prevention of OA. In these cases the aim is to restore joint surfaces that are at risk of OA from abnormal mechanics. This procedure is commonly performed in patients with slipped capital femoral epiphyses and developmental dysplasia of the hip. The procedure can also be directed against limited joint damage, where the load is transferred from the degenerate to a less diseased component. In the treatment of medial compartment degeneration of the knee, a proximal tibial valgus osteotomy will correct the varus deformity. Whether for prophylactic or therapeutic reasons, the patients considered for osteotomy are generally young, of normal body mass index, with a relatively good range of motion at the joint, and with only mild symptoms.
Arthrodesis, or joint fusion, is now a rare procedure to treat large joints affected by OA
and has largely been replaced by arthroplasty. Arthrodesis, however, is a reliable, durable, and painless solution to severe arthritis involving joints in the hand, foot, and spine, and, if successfully fused, exhibits surprisingly little limitation of motion.
Recently the experimental treatment of discrete areas of chondral damage in the knee has attracted attention. Traditionally chondral damage has been addressed with debridement, drilling of the subchondral bone, or osteo-chondral auto- and allografting. In autologous cartilage implantation, grafts of normal cartilage are harvested at arthroscopy from non-weight-bearing sites of the knee, cultered ex vivo to increase the number of cells, and transplanted back into the defect area, which is protected by a periosteal flap or embedded in a collagen matrix. This procedure is successful in well-selected patients with isolated disease in a stable knee. However, regrowth of hyaline cartilage at the defect site is not assured, and the ratios of hyaline to fibrocartilage at biopsy vary greatly. Biocartilage is predominantly composed of type I collagen, which has suboptimal wear characteristics. However, the technique demands two surgical procedures, and the overall outcome may not be significantly superior to that achieved with more conventional techniques .
Joint replacements constitute the biggest advance in the treatment of OA. Only 40 years ago there was no cure for the debilitating pain of OA, but today total joint replacements of the hip and knee are one of the triumphs of modern orthopaedic surgery. The earliest developments of total hip replacements by McKee and Farrar in the 1950s were optimized by Sir John Charnley 10 years later who used a stainless-steel stem that fitted into a polyethylene cup, both cemented into the hip and thighbone. With the help of specifically designed operating theaters and novel antibiotics, the success rate of joint replacement surgery has reached an unprecedented high level. The 1970s saw a proliferation of designs similar to the Charnley hip. A high failure rate in young and active patients who placed high demands on hip and knee prostheses posed the greatest challenge to orthopaedic surgeons. Often young and active patients were refused surgery, considerable pain and disability notwithstanding, until they reached an appropriate age for joint replacement. At the other end of the spectrum, many elderly patients were also excluded from surgery as the complication rate was thought to be unacceptably high. Since the early 1990s there has been phenomenal progress in terms of operative techniques, implant design, and orthopaedic anesthesia. There are now many different designs of prostheses that can be safely and reliably utilized in patients of all ages. The new prostheses pose minimal risk and provide maximum improvement in terms of quality of life. New prostheses utilize high-tech materials such as titanium and ceramics, and the surgical procedures now include not only total replacement but also resurfacing of the hip joint and unicondylar or half-knee replacements. It is hoped the new generation of total joint designs will last over 20 years, with complication rates of less than 1%. Patients are now encouraged to walk on the first postoperative day, a far cry from the bed rest of 6 weeks advocated in the not so distant past.
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