1. LECTURE DEGENERATIVE DISEASES OF THE JOINTS AND SPINE COLUMN (OSTEOARTHRITIS, OSTEOCHONDROSIS).

2. The problem of degenerative diseases of the joints and spine column is very acute in the last times. These diseases constitute from 1.5 to 3 per cents of all orthopaedic diseases in adults and frequently lead to considerable disability in the form of pain, stiffness and restricted mobility. Prompt diagnosis and early treatment are essential in any case to reduce the incidence of these complications. Most patients can be treated conservatively, but surgical treatment is sometimes necessary, especially in the patients whose weight-bearing joints are affected.

3. Osteoarthritis is an extremely common degenerative process which is responsible for considerable disability in the form of pain, stiffness and restricted mobility. Two forms are recognised: primary and secondary osteoarthritis. In primary osteoarthritis the aetiology is uncertain, although is likely that it is the end result of a number of pathological processes which lead to ‘joint failure’. In secondary osteoarthritis, one or more of many well recognised predisposing factors are seen to be present (Table 1). Osteoarthritis is an extremely common degenerative process which is responsible for considerable disability in the form of pain, stiffness and restricted mobility. Two forms are recognised: primary and secondary osteoarthritis. In primary osteoarthritis the aetiology is uncertain, although is likely that it is the end result of a number of pathological processes which lead to ‘joint failure’. In secondary osteoarthritis, one or more of many well recognised predisposing factors are seen to be present (Table 1).

4. Table 1 Aetiological factors in secondary osteoarthritis. Congenital: e.g. acetabular dysplasia, congenital dislocation of the hip Congenital: e.g. acetabular dysplasia, congenital dislocation of the hip Developmental: e.g. Perthes’ disease, slipped upper femoral epiphysis Developmental: e.g. Perthes’ disease, slipped upper femoral epiphysis Metabolic: e.g. gout, pseudogout Metabolic: e.g. gout, pseudogout Infective: e.g. staphylococcal, tuberculosis, brucellosis Infective: e.g. staphylococcal, tuberculosis, brucellosis Sexually transmitted: e.g. Reiter’s syndrome, gonococcal Sexually transmitted: e.g. Reiter’s syndrome, gonococcal Post-traumatic: e.g. from fractures involving the articular surfaces Post-traumatic: e.g. from fractures involving the articular surfaces Genetic: e.g. haemophilia (and related diseases), Gaucher’s disease, mucopolysaccharidoses, sickle cell anaemia Genetic: e.g. haemophilia (and related diseases), Gaucher’s disease, mucopolysaccharidoses, sickle cell anaemia Autoimmune diseases: e.g. rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis and other seronegative arthritides Autoimmune diseases: e.g. rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis and other seronegative arthritides Avascular necrosis: e.g. idiopathic, or secondary to fracture, caisson disease, alcohol abuse or steroids Avascular necrosis: e.g. idiopathic, or secondary to fracture, caisson disease, alcohol abuse or steroids

5. Pathological features The two fundamental features are cartilage damage and mechanical failure. Cartilage damage occurs in stages, and starts with a breakdown of the normal collagen fibre network and a reduction in proteoglycan concentration. This results in a loss of cartilage resilience, setting up a worsening spiral of events; the exposed collagen fibres have an affinity for water, which causes further swelling and proteoglycan depletion leading finally to loss of the mechanical integrity of the articular cartilage. Mechanical factors play a significant role in the degenerative process. The forces crossing a joint may be either excessive or applied over an abnormally small area, or there may be a combination of both these factors. The two fundamental features are cartilage damage and mechanical failure. Cartilage damage occurs in stages, and starts with a breakdown of the normal collagen fibre network and a reduction in proteoglycan concentration. This results in a loss of cartilage resilience, setting up a worsening spiral of events; the exposed collagen fibres have an affinity for water, which causes further swelling and proteoglycan depletion leading finally to loss of the mechanical integrity of the articular cartilage. Mechanical factors play a significant role in the degenerative process. The forces crossing a joint may be either excessive or applied over an abnormally small area, or there may be a combination of both these factors.

6. Cartilage: At first there is fibrillation of the superficial layers giving a frayed appearance to the surface. Subsequently, the cartilage develops deep fissures with fragmentation and detachment of cartilage fragments, leading to exposure of subchondral bone (Fig. 1) and the formation of loose bodies. Cartilage: At first there is fibrillation of the superficial layers giving a frayed appearance to the surface. Subsequently, the cartilage develops deep fissures with fragmentation and detachment of cartilage fragments, leading to exposure of subchondral bone (Fig. 1) and the formation of loose bodies.

7. Fig. 1. Femoral head (removed during the course of a joint replacement) showing loss of most of the articular cartilage.

8. Subchondral bone: An abrasive mechanism is probably responsible for eburnation (polishing) of the exposed bone which may develop a smooth, ivory-like appearance. Areas of segment necrosis and microfractures appear in the subchondral layers, resulting in increased osteobloastic activity which is responsible for increased uptake in isotopic bone scans. There is thickening of the subchondral plate and adjacent bony trabeculae leading to sclerosis, one of the cardinal radiological features of osteoarthritis. Subchondral bone: An abrasive mechanism is probably responsible for eburnation (polishing) of the exposed bone which may develop a smooth, ivory-like appearance. Areas of segment necrosis and microfractures appear in the subchondral layers, resulting in increased osteobloastic activity which is responsible for increased uptake in isotopic bone scans. There is thickening of the subchondral plate and adjacent bony trabeculae leading to sclerosis, one of the cardinal radiological features of osteoarthritis.

9. Subchondral pseudocysts: These are seen both histologically and in radiographs and represent areas of bone which have been replaced by myxomatous fibrous tissue. The lesions are thought to be the result of high intraarticular pressure forcing synovial fluid through defects in the joint surface into the marrow space. Although almost invariably present in osteoarthritis, they are by no means exclusive to this condition. Subchondral pseudocysts: These are seen both histologically and in radiographs and represent areas of bone which have been replaced by myxomatous fibrous tissue. The lesions are thought to be the result of high intraarticular pressure forcing synovial fluid through defects in the joint surface into the marrow space. Although almost invariably present in osteoarthritis, they are by no means exclusive to this condition.

10. Remodelling: This is striking feature which leads to an alteration of the joint contours. It is commonly seen in the hip joint where the normal spherical shape of the femoral head becomes flattened and marginal osteophytes (new bone) appear (Fig. 2). This process can lead to further restriction of joint nobility by acting as a physical block to motion. Remodelling: This is striking feature which leads to an alteration of the joint contours. It is commonly seen in the hip joint where the normal spherical shape of the femoral head becomes flattened and marginal osteophytes (new bone) appear (Fig. 2). This process can lead to further restriction of joint nobility by acting as a physical block to motion.

11. Fig. 2. Osteoarthritis (OA) of the hip with remodelling the femoral head which is no longer spherical. Fig. 2. Osteoarthritis (OA) of the hip with remodelling the femoral head which is no longer spherical.

12. Clinical features Symptoms: Symptoms: Pain Pain Stiffness, particularly in the morning, is a variable phenomenon and usually reflects capsular fibrosis and/or protective muscle spasm. Stiffness, particularly in the morning, is a variable phenomenon and usually reflects capsular fibrosis and/or protective muscle spasm. Swelling Swelling Functional disability Functional disability

13. Signs: Commonly only one joint is affected, usually a weight-bearing one (the knee or hip). There may be muscle wasting in the area, and in the palpable joints tenderness is almost universal. Palpable osteophytes or joint effusion may be responsible for swelling. Synovial thickening is not a major feature in osteoarthritis. In the case of the knee there may be obvious deformity (e.g. genu valgum or varum, or one of fixed flexion), while in the hip the joint may be flexed, adducted and internally rotated. Signs: Commonly only one joint is affected, usually a weight-bearing one (the knee or hip). There may be muscle wasting in the area, and in the palpable joints tenderness is almost universal. Palpable osteophytes or joint effusion may be responsible for swelling. Synovial thickening is not a major feature in osteoarthritis. In the case of the knee there may be obvious deformity (e.g. genu valgum or varum, or one of fixed flexion), while in the hip the joint may be flexed, adducted and internally rotated.

14. Investigations X-ray examination X-ray examination

15. Fig. 3. Early OA right hip, with slight joint space narrowing and early lipping. Advanced OA on the left, with gross narrowing of joint space, marginal sclerosis of the acetabulum, and cystic changes in the femoral head. Fig. 3. Early OA right hip, with slight joint space narrowing and early lipping. Advanced OA on the left, with gross narrowing of joint space, marginal sclerosis of the acetabulum, and cystic changes in the femoral head.

16. Fig. 4. Osteoarthritis of the distal and proximal interphalangeal joints of the fingers. Fig. 4. Osteoarthritis of the distal and proximal interphalangeal joints of the fingers.

17. Fig. 5. Radiograph showing osteoarthritic subluxation of the distal interphalangeal joint and the formation of a Heberen’s node. Fig. 5. Radiograph showing osteoarthritic subluxation of the distal interphalangeal joint and the formation of a Heberen’s node.

18. The degree of osteoarthritis has been classified by N. S. Kosinskaya as shown in Table 2. Table 2 Classification of degree of osteoarthritis. Classification of degree of osteoarthritis.GradePain Level of activity The range of movement Radiological changes Grade 1 Slight and occasional pain. Weight bearing is possible. A patient may able to perform certain activities of daily living. The range of movement in the joint is not limited or there is loss of part of the range of movements in the joint. Slight narrowing of joint space. Small marginal osteophytes. Grade 2 Moderate pain, but a patient may be able to weight bear albeit with pain. There is increasing difficulty in walking and standing. Moderate limitations of movement, contractures and fixed flexion deformities with apparent shortening of the affected limb. There are pain and crepitus on movement. Gross narrowing of joint space. Moderate marginal osteophytes and cysts. Subchondral bone sclerosis. An alteration of the joint contours. Grade 3 Moderate or severe pain. A patient has had to modify or give up activities or both because of pain and progressive loss of movement. Great stiffness in the affected joint (rigidity). Loss of joint space. Massive marginal osteophytes. Osteoporosis of the articular end of the bone. Areas of new bone formation round the joint.

19. Treatment Conservative measures: Weight reduction is important in the obese patient whose weight- bearing joints are affected. This not only reduces joint stresses, but may facilitate many surgical intervention should this become necessary. Physiotherapy is useful in maintaining a functional range of motion. Splintage can be useful in the acute arthritic joint but should be used for brief periods only to avoid producing stiffness. In the lower limb, a walking stick will help to reduce the loading on the affected joint. Modification of activities may help to relieve pain, although exercising within the limits of pain should be encouraged. Conservative measures: Weight reduction is important in the obese patient whose weight- bearing joints are affected. This not only reduces joint stresses, but may facilitate many surgical intervention should this become necessary. Physiotherapy is useful in maintaining a functional range of motion. Splintage can be useful in the acute arthritic joint but should be used for brief periods only to avoid producing stiffness. In the lower limb, a walking stick will help to reduce the loading on the affected joint. Modification of activities may help to relieve pain, although exercising within the limits of pain should be encouraged.

20. Medical treatment: Where the pain is mild, simple analgesics like aspirin or paracetamol can be used. In patients with more severe pain, nonsteroidal anti-inflammatory agents such as ibuprofen or indomethacin, taken on a regular basis, can produce satisfactory relief. It is important to use these drugs which care if there is a history of gastrointestinal pathology. Medical treatment: Where the pain is mild, simple analgesics like aspirin or paracetamol can be used. In patients with more severe pain, nonsteroidal anti-inflammatory agents such as ibuprofen or indomethacin, taken on a regular basis, can produce satisfactory relief. It is important to use these drugs which care if there is a history of gastrointestinal pathology.

21. Surgical treatment: Arthrodesis or joint fusion Arthrodesis or joint fusion Arthroplasty Arthroplasty Osteotomy Osteotomy Excision arthroplasty Excision arthroplasty Joint replacement Joint replacement

22. With this information the following points should be noted: The incidence of osteoarthritis increases with age. The incidence of osteoarthritis increases with age. It commonly affects a single joint. It commonly affects a single joint. The pathology primarily involves the articular cartilage. The pathology primarily involves the articular cartilage. Medical treatment should always be tried first. Medical treatment should always be tried first. There are several surgical options but in the hip and knee, total joint arthroplasty is the treatment of choice for advanced disease. There are several surgical options but in the hip and knee, total joint arthroplasty is the treatment of choice for advanced disease.