A casting method for measuring the intra-articular space in the loaded hip is described. The results of tests on 22 hips from 22 cadavers show that the joint space is variable both in location and size and can disappear under light loads. It seems likely that the size and shape of the space influence how much access synovial fluid has for lubrication and nutrition.

1. Transient synovitis is an acute, and at times exudative, condition of the synovial membrane.

2. There is no particular association with injury or with upper respiratory infection.

3. The course is short and benign with complete resolution. The occasional hip with chronic or recurrent symptoms can be distinguished from Legg-Perthes' disease by the shorter history, normal radiographs and the complete resolution.

4. There is no evidence that transient synovitis leads to avascular changes in the femoral head.

The findings in a child with bilateral congenital dislocation of the hips who died shortly after birth are described. The only significant abnormality present was redundancy of the capsular ligaments and elongation of the ligament of the femoral head. The relationship between the orientation of the femoral neck and of the acetabulum was within normal limits. The significance of these findings in relation to etiology and management are discussed.

1. The results of treatment of twenty-five disintegrated tuberculous hips by excision, arthrodesis and anti-tuberculous drugs are reported.

2. The methods used are described.

3. Sound healing and bony fusion was obtained in all but three of the twenty-five hips treated.

General remarks–Comparison of the two reviews shows that patients with good results return more readily for a review than those with poor results. In middle-aged patients with some disability for walking an attendance of 80 per cent at least is necessary in order to obtain a representative follow-up five to ten years after operation.

An outstanding feature of all the operations reviewed is the degree of lasting relief of pain. It is rare to find that a patient with severe hip pain before operation has pain of the same severity after any of these operations at least up to ten years afterwards, and probably for much longer. Generally speaking, although in advancing years stiffness of the hip is undoubtedly a handicap, it is preferable to instability, particularly if this is progressive. A patient can adapt himself to and accept a disability that is permanent and unaltering, but instability increasing in later years can be distressing mentally and incapacitating physically.

Cup arthroplasty–There is an element of unpredictability in the results, especially the late results, of cup arthroplasty. Movement decreases and there is a tendency for pain and instability to increase after four or five years. There is little to indicate which case will be successful although the results vary according to the condition for which operation is performed. The operation gives good results, on the whole, for osteoarthritis, particularly when the operation is done on one hip only. Stability is much more important when both hips are involved, and, unless this is good in at least one hip, the results of bilateral operations are poor. "Excellent" results are not obtained in rheumatoid arthritis but few results are "poor." Operations for congenital dislocation of the hip give the most disappointing results. In operations for ankylosing spondylitis there is a high incidence of stiffening of the hip, but many patients are greatly improved in comparison to their state before operation.

Displacement osteotomy–The hazard in displacement osteotomy is ankylosis, particularly when internal fixation is not used. Relief of pain and stability are well maintained. The results in general, and for pain in particular, are less good when internal fixation is used. Adduction of the upper fragment of the femur appears to be of value in the production of a good result. In the series examined it was less often achieved when internal fixation was the method of immobilisation. The best results were obtained in cases of congenital dislocation of the hip and there were few "poor" results in cases of congenital subluxation.

Excision of the head and neck of the femur and Batchelor's operation–Rehabilitation may take a long time, but the late results are more predictable than in the other operations reviewed. A "fair" result is more likely than an "excellent" one, but late "poor" results are few. Relief of pain is better after excision of the head and neck than after any other operation reviewed.

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.

1. Experimental evidence is advanced to suggest that the effect of the McMurray displacement osteotomy in osteoarthritis of the hip is to diminish the load carried by the head of the femur, firstly by correction of deformity, and secondly by a "pelvic support" action.

2. A review of seventy-five cases has revealed certain important details in selection and operative management. The end-results indicate that the operation, when correctly performed, is successful in relieving pain and diminishing disability.

We have endeavoured to make known the results of a simple type of arthroplasty of the hip which is well tolerated even by elderly patients. It has not been the purpose of this article to compare former operations with our own, a newcomer in the field of surgery of the hip. In particular we do not wish to compare our comparatively recent results with Smith-Petersen's well-established method of cup arthroplasty—a magnificent contribution to the surgery of the region. The results we have already obtained, however, appear sufficiently favourable to merit further study and development of the method. If the future confirms the value of our early results, we shall perhaps be able to suggest operation to patients who suffer more from loss of function than from pain.

We compared revision and mortality rates of 4668 patients undergoing primary total hip and knee replacement between 1989 and 2007 at a University Hospital in New Zealand. The mean age at the time of surgery was 69 years (16 to 100). A total of 1175 patients (25%) had died at follow-up at a mean of ten years post-operatively. The mean age of those who died within ten years of surgery was 74.4 years (29 to 97) at time of surgery. No change in comorbidity score or age of the patients receiving joint replacement was noted during the study period. No association of revision or death could be proven with higher comorbidity scoring, grade of surgeon, or patient gender.

We found that patients younger than 50 years at the time of surgery have a greater chance of requiring a revision than of dying, those around 58 years of age have a 50:50 chance of needing a revision, and in those older than 62 years the prosthesis will normally outlast the patient. Patients over 77 years old have a greater than 90% chance of dying than requiring a revision whereas those around 47 years are on average twice as likely to require a revision than die. This information can be used to rationalise the need for long-term surveillance and during the informed consent process.

Aims. To analyse the effectiveness of debridement and implant retention (DAIR) in patients with hip periprosthetic joint infection (PJI) and the relationship to patient characteristics. The outcome was evaluated in hips with confirmed PJI and a follow-up of not less than two years. Patients and Methods. Patients in whom DAIR was performed were identified from our hip arthroplasty register (between 2004 and 2013). Adherence to criteria for DAIR was assessed according to a previously published algorithm. Results. DAIR was performed as part of a curative procedure in 46 hips in 42 patients. The mean age was 73.2 years (44.6 to 87.7), including 20 women and 22 men. In 34 hips in 32 patients (73.9%), PJI was confirmed. In 12 hips, the criteria for PJI were not fulfilled and antibiotics stopped. In 41 (89.1%) of all hips and in 32 (94.1%) of the confirmed PJIs, all criteria for DAIR were fulfilled. In patients with exogenous PJI, DAIR was performed not more than three days after referral. In haematogenous infections, the duration of symptoms did not exceed 21 days. In 28 hips, a single debridement and in six hips two surgical debridements were required. In 28 (87.5%) of 32 patients, the total treatment duration was three months. Failure was noted in three hips (9%). Long-term follow-up results (mean 4.0 years, 1.4 to 10) were available in 30 of 34 (88.2%) confirmed PJIs. The overall successful outcome rate was 91% in 34 hips, and 90% in 30 hips with long-term follow-up results. . Conclusion. Prompt surgical treatment with DAIR, following strict diagnostic and therapeutic criteria, in patients with suspected periprosthetic joint infection, can lead to high rates of success in eradicating the infection. Cite this article: Bone Joint J 2017;99-B:330–6