Axial radiographs were obtained under valgus and external rotation stress at 45° of knee flexion with and without contraction of the quadriceps muscle in order to assess the dynamics of patellar subluxation or dislocation. The radiography was performed on 82 knees in 61 patients with patellofemoral instability, and on 44 normal knees. The lateral patellofemoral angle and the congruence angle were measured and compared with the conventional Merchant views. Both parameters showed greater differences between symptomatic and normal knees on the stress radiographs obtained without quadriceps contraction. There was a major difference in the lateral patellofemoral angles between the groups, which clearly distinguished symptomatic knees from normal controls. Congruence angles on stress radiography had a significant correlation with the functional scores obtained after a period of conservative treatment and a positive correlation with the frequency of patellar subluxation. When the quadriceps contracted, two patterns of patellar shift were observed. While the patella reduced into the trochlear groove in all normal knees and about 70% of the symptomatic knees, contraction of the quadriceps caused further subluxation of the patella in the remaining symptomatic knees. All the knee joints which showed this displacement failed to respond to conservative treatment and eventually required surgical treatment. Thus, this technique of stress radiography is a simple, cost-effective and useful method of evaluating patellar instability and predicting the prognosis

Cadaver knee joints were mounted so that life-like forces of weight-bearing were simulated. The patello-femoral contact areas were defined under load throughout the range of movement by the dye method. During movement from extension to 90 degrees of flexion a band of contact sweeps across the patella from inferior to superior pole, but the odd facet makes no contact. At about 135 degrees of flexion separate medial and lateral contact areas form, the medial one limited to the odd facet. From extension to 90 degrees of flexion the patella holds the quadriceps tendon away from the femur, but in further degrees of flexion an extensive "tendo-femoral" contact area forms. Between 90 degrees and 135 degrees of flexion the patella rotates and the ridge between the medial and odd facets engages the femoral condyle. The odd facet is shown to be a habitual non-contact area and the ridge to be subject to high load, observations which correlate with cartilage lesions described in Part 2 of the paper

1. Joint compliance estimations were made on the knee joints of fourteen patients with rheumatoid arthritis, three patients with osteoarthritis and three healthy volunteers. 2. Diminishing values for capsular compliance were found in the normal volunteers, the patients under the age of thirty-five years with rheumatoid arthritis, the patients with osteoarthritis and the patients over the age of forty years with rheumatoid arthritis respectively. 3. In the young adult normal volunteers the average compliance was 8·1 cubic centimetres per millimetre of mercury at an intra-articular pressure of 5 millimetres of mercury and 0·7 cubic centimetre per millimetre of mercury at 50 millimetres of mercury. In the older patients with rheumatoid disease the average compliance was 2·1 cubic centimetres per millimetre of mercury at 5 millimetres of mercury and 0·4 cubic centimetre per millimetre of mercury at 50 millimetres of mercury. 4. Both the effects of ageing and the effects of disease appeared to be responsible for the low capsular compliance observed in patients over the age of forty years with rheumatoid arthritis, but duration of disease did not seem to be a contributing factor

A retrospective series of 272 operatively proven bucket-handle tears of the meniscus has been studied to define the natural history of the tear and to assess the accuracy of arthrography as a diagnostic technique. A simple twist, or a sporting injury accounted for most tears in the 196 patients on whom information was sufficient to allow analysis. There was, however, either no known trauma or merely a history of crouching in 20 per cent of patients. These were distributed evenly throughout the age range. Most of the 272 patients presented either with a locked knee (43 per cent) or with a history of locking (37 per cent). Fifty per cent of those with a previous history of locking but who were clinically unlocked at the time of operation, had displaced bucket-handle tears, indicating that unlocking of the knee joint frequently represents anterior extension of the tear, rather than relocation of the displaced fragment of meniscus. Significant meniscal tears were identified in 77 per cent of the 187 arthogram reports that were studied. Most errors in diagnosis seemed to occur when the separated fragment was hidden in the intercondylar notch and the peripheral rim was misinterpreted as an intact meniscus

The clinical records, radiographs and histopathological material of all forty-one patients recorded as suffering from fibrosarcoma of bone in the Swedish Cancer Registry for the years 1958 to 1968 have been analysed; in addition, four cases were found on histological review of a series of osteosarcomas. From this re-examination, twenty-four patients with genuine fibrosarcoma of bone were identified; twenty-two had primary neoplasms and two secondary. No sex or geographical differences were found. The tumours showed a prevalence for patients in the adult and older age groups. Half of the tumours arose from femoral or tibial metaphysial bone adjacent to a knee joint. All the tumours were of the medullary type. Almost one-third presented with a pathological fracture, and soft-tissue extension had occurred in all but three tumours. In contrast to previous reports, these tumours were more malignant than osteosarcomas and showed a five-year survival rate of only 4-2 per cent. In accessible sites, ablative surgery was used as the primary treatment, Fibrosarcoma of bone is a distinctive lesion and should be distinguished carefully from periosteal and soft-tissue fibrosarcomas because of differences in prognosis and treatment

1. Articular cartilage from immature rabbits was placed in and near the rabbit knee joints for periods up to ten weeks. 2. Autografts of articular cartilage when placed free in the joint soon became adherent to its synovial lining; the cartilage with its subchondral bone remained viable. 3. Homografts remained viable in the presence of joint fluid, but when in contact with synovium antigenic cellular reaction was produced early. The presence of subchondral bone intensified this reaction and led to graft invasion and destruction. 4. Partial thickness homografts of articular cartilage were also antigenic and were absorbed. When full thickness cartilage was used, this cellular invasion was resisted by the zone of provisional calcification which appeared to function as a physical barrier against antigenic cells of the host. 5. When placed in muscle, both autogenous and homogenous grafts failed to survive through lack of nutrition, although the autogenous subchondral bone remained viable. It is inferred that subchondral circulation is not sufficient for cartilage survival and synovial fluid is essential for its proper nutrition. 6. Surviving immature articular cartilage transplants underwent "ageing" changes

Objectives

This study aimed to examine the effects of SRT1720, a potent SIRT1 activator, on osteoarthritis (OA) progression using an experimental OA model.

1. In this series of 150 cases of arthritis of the hip joint treated by vitallium mould arthroplasty (182 arthroplasties), 80 per cent. of late results are satisfactory to both patient and surgeon. 2. Striking features are the relative painlessness, smooth hip joint movement, progressive improvement in function, and reformation of the joint lines as seen radiographically in the post-operative period. 3. Function after arthroplasty for traumatic and degenerative arthritis approaches the normal hip joint much more closely than in cases of infective and rheumatoid arthritis. 4. There is a complete absence of low back symptoms or postural difficulties, and there is no difficulty in preventing stiffness of the knee joint. 5. Different technical procedures are indicated according to the degree of absorption of the femoral head or neck, and the stability of the mould in the acetabulum. 6. The operative mortality rate in this series was nil, and during the six-year follow-up period only one case died as the result of a complication of the arthroplasty. 7. In addition to meticulous operative technique and the use of special instruments, the importance of careful and prolonged after-treatment must be stressed. 8. It must also be emphasised that secondary operative revisions are often necessary, particularly in cases of infective and rheumatoid arthritis

1 . Current theories of the etiology of chondromalacia patellae do not explain satisfactorily either its great frequency or its common site of origin on the medial patellar facet. 2. The etiology can be more logically explained by the presence of a ridge on the upper anterior border of the cartilage of the medial femoral condyle, in most knees. This ridge, consisting of cartilage, or cartilage and bone, varies considerably in height and, in normal knee joint movement, causes considerable friction on the medial patellar facet. 3. The degenerative changes were found to be greater in the presence of the larger ridges, and–because of longer wear and tear–in the older patients. 4. This study indicates that chondromalacia was more severe in women than in men, and in patients overweight. Although the activity of the individual and the power of the quadriceps mechanism must play an extremely important part in this condition, it was not possible to assess this. 5. Two factors previously considered to be important in the etiology of this condition, namely, the length of the patellar tendon and Wiberg's Type III patellar shape, have not been confirmed in this study. 6. Resulting from the present investigation certain precautions are suggested in rehabilitation after operations on the knee, and a surgical method for discouraging the progress of this common, and sometimes disabling, condition has been devised

Objectives

Prosthetic joint infection (PJI) diagnosis is a major challenge in orthopaedics, and no reliable parameters have been established for accurate, preoperative predictions in the differential diagnosis of aseptic loosening or PJI. This study surveyed factors in synovial fluid (SF) for improving PJI diagnosis.

Aims

Patellofemoral problems are a common complication of total knee arthroplasty. A high compressive force across the patellofemoral joint may affect patient-reported outcome. However, the relationship between patient-reported outcome and the intraoperative patellofemoral contact force has not been investigated. The purpose of this study was to determine whether or not a high intraoperative patellofemoral compressive force affects patient-reported outcome.

1. Three hundred and twenty cases of tuberculosis of the hip joint have been analysed and the late results assessed three or more years after discharge from hospital. 2. The primary bone focus involved the acetabulum alone in 39·3 per cent; the acetabulum and femoral head in 34·1 per cent; the head of femur alone in 19·2 per cent, and the femoral neck alone in 7·4 per cent. In 101 cases widespread destruction of the joint had taken place by the time the patient first came under observation. 3. Premature epiphysial fusion round the knee joint of the affected side occurred in 23 per cent of all patients under the age of fifteen years. 4. When hip disease was complicated by multiple foci of active tuberculosis or by secondarily infected abscesses and sinuses, the prognosis was seriously worsened. 5. Significant late deformity occurred in 38·3 per cent of patients discharged with "sound" fibrous ankylosis, and in 60·5 per cent of those with an unstable fibrous ankylosis. 6. Of 187 patients observed for more than three years after discharge from hospital 174 returned to full activity, seven were partly incapacitated and six were totally incapacitated. 7. Analysis of the late results suggests that the prognosis is best when an adequate period of conservative treatment is followed by some form of arthrodesis operation

1. The synovial membrane and capsule in osteoarthritis of the hip have been studied in twenty-five cases. Dissections have been made on fresh cadavers to establish the normal structure and function of these tissues at different ages. 2. Fragments of bone and cartilage were found beneath the synovial surface in twenty-three cases of the twenty-five cases of osteoarthritis. 3. The source of these fragments is the degenerate articular surfaces. 4. The fibrosis of the synovial membrane and capsule follows the synovial hyperplasia which accompanies the phagocytosis of these fragments. 5. A similar histological picture has been produced by injecting fragmented cartilage into the knee joints of rabbits. The injected fragments are found beneath the surface, and synovial hyperplasia is followed by subsynovial fibrosis. 6. The greatest amount of this joint debris is found in the lowest part of the joint cavity. 7. The joint capsule is particularly sensitive to traction. 8. All parts of the capsule are tight in extension, which is the weight-bearing position. 9. Fibrotic shortening of the capsule in the lowest part of the joint cavity explains many of the symptoms and signs of the disease: pain is caused by an attempt to stretch the capsule; muscle spasm occurs in the muscles supplied by the sensory nerves of this part of the capsule; extension, medial rotation and abduction, which tighten this area, are lost first; progressive shortening causes deformity in the opposite direction, namely flexion, lateral rotation and adduction; the loss of extension causes a more rapid wearing of articular cartilage on weight bearing; subperiosteal new bone is formed on the under-surface of the neck of the femur. 10. The symptomatology is discussed

Objectives

To compare the effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament (ACL) reconstruction animal model.

Aims

The objective of this study was to compare early postoperative functional outcomes and time to hospital discharge between conventional jig-based total knee arthroplasty (TKA) and robotic-arm assisted TKA.

Aims

The aims of this study were to evaluate the abductor function in moderate and severe slipped capital femoral epiphysis (SCFE), comparing the results of a corrective osteotomy at the base of the femoral neck and osteoplasty with 1) in situ epiphysiodesis for mild SCFE, 2) contralateral unaffected hips, and 3) hips from healthy individuals.

Objectives

Given the function of adiponectin (ADIPOQ) on the inflammatory condition of obesity and osteoarthritis (OA), we hypothesized that the ADIPOQ gene might be a candidate gene for a marker of susceptibility to OA.