The role of inflammatory cells in aseptic loosening and failure of cemented joint replacements is unclear. Inflammatory cells from the revision joint capsule of four failed hip arthroplasties were examined to determine their nature and resorptive capacity. The capsules contained numerous macrophages and abundant foreign-body macrophage polykaryons, distinguished from osteoclasts by their antigenic phenotype and lack of response to calcitonin. When cultured on cortical bone slices in vitro, both macrophages and macrophage polykaryons produced small resorption pits and were associated with areas of superficial resorption of the bone surface. These results indicate that foreign-body induced macrophages and macrophage polykaryons are capable of a type of low-grade bone resorption which may be of pathogenic significance in the loosening of cemented joint prosthetic components

Aims. Surgical approaches that claim to be minimally invasive, such as the direct anterior approach (DAA), are reported to have a clinical advantage, but are technically challenging and may create more injury to the soft-tissues during joint exposure. Our aim was to quantify the effect of soft-tissue releases on the joint torque and femoral mobility during joint exposure for hip resurfacing performed via the DAA. Methods. Nine fresh-frozen hip joints from five pelvis to mid-tibia cadaveric specimens were approached using the DAA. A custom fixture consisting of a six-axis force/torque sensor and motion sensor was attached to tibial diaphysis to measure manually applied torques and joint angles by the surgeon. Following dislocation, the torques generated to visualize the acetabulum and proximal femur were assessed after sequential release of the joint capsule and short external rotators. Results. Following initial exposure, the ischiofemoral ligament (7 to 8 o’clock) was the largest restrictor of exposure of the acetabulum, contributing to a mean 25% of overall external rotational restraint. The ischiofemoral ligament (10 to 12 o’clock) was the largest restrictor of exposure of the proximal femur, contributing to 25% of overall extension restraint. Releasing the short external rotators had minimal contribution in torque generated during joint exposure (≤ 5%). Conclusion. Adequate exposure of both proximal femur and acetabulum may be achieved with minimal torque by performing a full proximal circumferential capsulotomy while preserving short external rotators. The joint torque generated and exposure achieved is dependent on patient factors; therefore, some cases may necessitate further releases. Cite this article: Bone Joint J 2024;106-B(3 Supple A):59–66

In developmental dysplasia of the hip, a deficient acetabulum may be augmented by placing local autogenous iliac osseous graft, or the ilium itself, over the head of the femur with the expectation that the added bone will function as a bearing surface. We analysed this bone obtained en bloc during subsequent surgery which was performed for degenerative osteoarthritis in three patients at 6, 25 and 30 years after the initial augmentation procedure. In each patient, the augmentation comprised of red cancellous bone covered on its articulating surface by a distinct layer of white tissue. Microscopy of this tissue showed parallel rows of spindle-shaped cells lying between linearly arranged collagen bundles typical of joint capsule. Biochemical analysis showed type I collagen, the principal collagen of joint capsule and bone, with no significant quantity of type II collagen, the principal collagen of cartilage. While the added bone produced by acetabular augmentation was durable, histological and biochemical analyses suggested that it had not undergone cartilage metaplasia. The augmented acetabulum articulates with the head of the femur by means of an interposed hip joint capsule

Anatomical descriptions of the lateral retinaculum have been published, but the attachments, name or even existence of its tissue bands and layers are ill-defined. We have examined 35 specimens of the knee. The deep fascia is the most superficial layer and the joint capsule is the deepest. The intermediate layer is the most substantial and consists of derivatives of the iliotibial band and the quadriceps aponeurosis. The longitudinal fibres of the iliotibial band merge with those of the quadriceps aponeurosis adjacent to the patella. These longitudinal fibres are reinforced by superficial arciform fibres and on the deep aspect by transverse fibres of the iliotibial band. The latter are dense and provide attachment of the iliotibial band to the patella and the tendon of vastus lateralis obliquus. Our study identifies two important new findings which are a constant connection of the deep fascia to the quadriceps tendon superior and lateral to the patella, and, a connection of the deeper transverse fibres to the tendon of vastus lateralis obliquus

Aims

Frozen shoulder is a common and debilitating condition characterized by pain and restricted movement at the glenohumeral joint. Various treatment methods have been explored to alleviate symptoms, with suprascapular nerve block (SSNB) emerging as a promising intervention. This meta-analysis aimed to assess the effectiveness of SSNB in treating frozen shoulder.

We prospectively studied 86 children to assess the value and accuracy of isotope bone scanning in the diagnosis of suspected acute haematogenous osteomyelitis and septic arthritis. The patients were scanned because of difficulty in localising the exact site of the pathology. Characteristic scan appearances were found. In osteomyelitis there was increased or decreased uptake extending beyond the confines of the joint capsule; in septic arthritis there was increased or decreased uptake on either side of the joint line, but largely limited to and uniform within the joint capsule. The bone-scan images were correlated with the final diagnosis in 34 sites of septic arthritis and in 62 sites of osteomyelitis. The overall accuracy of the bone scans was 81%. The predictive value for a positive scan to be correct was 100% for a cold scan and 82% for a hot scan. The main reason for a false-positive scan was contiguous soft-tissue infection. The predictive value for a negative scan to be correct was 63%. One reason for a false-negative scan was that the patient was in the transitional phase from cold to hot

Aims

Intra-articular (IA) tumours around the knee are treated with extra-articular (EA) resection, which is associated with poor functional outcomes. We aim to evaluate the accuracy of MRI in predicting IA involvement around the knee.

Aims

Dislocation of the hip remains a major complication after periacetabular tumour resection and endoprosthetic reconstruction. The position of the acetabular component is an important modifiable factor for surgeons in determining the risk of postoperative dislocation. We investigated the significance of horizontal, vertical, and sagittal displacement of the hip centre of rotation (COR) on postoperative dislocation using a CT-based 3D model, as well as other potential risk factors for dislocation.

Aims

Histology is widely used for diagnosis of persistent infection during reimplantation in two-stage revision hip and knee arthroplasty, although data on its utility remain scarce. Therefore, this study aims to assess the predictive value of permanent sections at reimplantation in relation to reinfection risk, and to compare results of permanent and frozen sections.

Aims

The aim of this study was to evaluate the kinematics of the elbow following increasing length of the radius with implantation of radial head arthroplasties (RHAs) using dynamic radiostereometry (dRSA).

Aims

Over time, the locking mechanism of Modular Universal Tumour and Revision System (MUTARS) knee arthroplasties changed from polyethylene (PE) to polyether-ether-ketone Optima (PEEK) and metal-on-metal (MoM) in an attempt to reduce the risk of mechanical failure. In this study, we aimed to assess the cumulative incidence of locking mechanism revision for symptomatic instability by type of material, and assess potential associated risk factors.

Aims

The aim of this study was to evaluate the diagnostic accuracy of the absolute synovial polymorphonuclear neutrophil cell (PMN) count for the diagnosis or exclusion of periprosthetic joint infection (PJI) after total hip (THA) or knee arthroplasty (TKA).

Aims

The Birmingham Hip Resurfacing (BHR) was introduced in 1997 to address the needs of young active patients using a historically proven large-diameter metal-on-metal (MoM) bearing. A single designer surgeon’s consecutive series of 130 patients (144 hips) was previously reported at five and ten years, reporting three and ten failures, respectively. The aim of this study was to extend the follow-up of this original cohort at 25 years.

Aims

To analyze the short-term outcome of two types of total wrist arthroplasty (TWA) in terms of wrist function, migration, and periprosthetic bone behaviour.

There has been a marked increase in the number of hip arthroscopies performed over the past 16 years, primarily in the management of femoroacetabular impingement (FAI). Insights into the pathoanatomy of FAI, and high-level evidence supporting the clinical effectiveness of arthroscopy in the management of FAI, have fuelled this trend. Arthroscopic management of labral tears with repair may have superior results compared with debridement, and there is now emerging evidence to support reconstructive options where repair is not possible. In situations where an interportal capsulotomy is performed to facilitate access, data now support closure of the capsule in selective cases where there is an increased risk of postoperative instability. Preoperative planning is an integral component of bony corrective surgery in FAI, and this has evolved to include computer-planned resection. However, the benefit of this remains controversial. Hip instability is now widely accepted, and diagnostic criteria and treatment are becoming increasingly refined. Instability can also be present with FAI or develop as a result of FAI treatment. In this annotation, we outline major current controversies relating to decision-making in hip arthroscopy for FAI.

Cite this article: Bone Joint J 2022;104-B(5):532–540.

A reversed Delta III total shoulder prosthesis was retrieved post-mortem, eight months after implantation. A significant notch was evident at the inferior pole of the scapular neck which extended beyond the inferior fixation screw. This bone loss was associated with a corresponding, erosive defect of the polyethylene cup. Histological examination revealed a chronic foreign-body reaction in the joint capsule. There were, however, no histological signs of loosening of the glenoid base plate and the stability of the prosthetic articulation was only slightly reduced by the eroded rim of the cup

A study of the attachment of the joint capsule to the scapula, and of the shape of the humeral head, has been carried out in 52 fetal and embryonic shoulders. In 77% of cases the anterior capsule was attached to the labrum or close to it; in the remaining 23% it was inserted into the neck of the scapula, so creating a pouch. In all 52 specimens the humeral head was spherical. It was concluded that the pouched and redundant anterior capsule sometimes seen during surgery for recurrent dislocation of the shoulder, may not be traumatic in origin, but could be a developmental variant

In a series of 1160 arthroscopies we found 16 meniscal cysts; 12 involved the lateral joint line and two the medial, and two were intra-articular. In all but two cases, arthroscopy showed meniscal tears. We recommend arthroscopy of all cases to correct the meniscal lesion, and to evacuate the cyst into the joint by opening the joint capsule. This was successful in 12 cases, with no recurrence after an average follow-up of 18 months. Only two patients with no meniscal lesion on arthroscopy required an additional external incision for cyst removal

We studied the origin of extensor carpi radialis brevis using 40 fresh frozen human cadaver specimens. Ten were stained with haematoxylin and eosin and trichrome which showed the collagenous structure of the extensor tendons at their origin. Gross anatomical observation showed that there was no definitive separation between brevis and communis at the osseotendinous junction. The histological findings confirmed the lack of separation between the two tendons. The extensor tendons were in close proximity to the joint capsule but trichrome staining showed no interdigitation of the tendon with the capsule. The validity of ascribing the pain of lateral epicondylitis to extensor carpi radialis brevis must be questioned. It appears to arise more from the ‘common extensor’ origin

Two boys with entrapment of the median nerve in the elbow joint after closed reduction of a posterior dislocation with fracture of the medial epicondyle showed a characteristic radiological sign in the anteroposterior radiograph after two to three months. The sign was a depression in the cortex on the ulnar side of the distal humeral metaphysis, with interruption of the local periosteal reaction. At operation in both patients the depression was found to correspond with the place where the median nerve reached the posterior surface of the humerus. Radiographs taken after transverse section of the nerve above and below the joint capsule and end-to-end suture showed gradual disappearance of the cortical depression

We report the technique and results of a new method of debridement arthroplasty for advanced primary osteoarthritis of the elbow. Triceps and the periosteum of the olecranon are reflected towards the ulnar side and the joint is opened by dividing the radial collateral ligament. Osteophytes are removed, the olecranon and coronoid fossae are deepened and the fibrosed anterior joint capsule is excised. The degenerative changes are always more advanced on the radial side, with erosion of the capitellum, and it is usually necessary to remodel the head of the radius. In 29 elbows reviewed at a mean of 64 months, the average gain of range of motion was 34 degrees, with good pain relief and improved grip in most patients. Two elbows required reoperation but there were no other serious complications

We measured the range of rotation in both hips of 397 normal children and in the unaffected hip of 135 children with unilateral congenital dislocation of the hip. Both groups were assessed for generalised joint laxity. Joint laxity was more common in normal children with an internally centred arc of hip rotation than in normal children with a neutral or an externally rotated arc. The children with congenitally dislocated hips had significantly more joint laxity than did the control group and significantly more of them had an internally centred arc of hip rotation. We suggest that the lax joint capsule fails to mould away the neonatal anteversion of the femoral neck during the first few months of life

The role of atmospheric pressure in providing static stability of the shoulder was studied experimentally in 24 cadaveric shoulders. Atmospheric air was allowed to enter the joint after puncturing the capsule. Three types of experiment were performed: in the first, the capsule was punctured after sequential division of the muscles; in the second, atmospheric air was let in by percutaneous puncture of of the capsule without dividing the muscles; and in the third, air was first let into the joint by percutaneous puncture of the capsule and then the muscles of the shoulder were divided. It was found that the intact shoulder subluxated after percutaneous puncture even without division of the overlying muscles or the capsule. Our findings suggest that negative pressure and muscle tone are the main static stabilisers of the shoulder, rather than the joint capsule

1. The results of Chiari pelvic osteotomy have been examined two to six years after operation in a group of eighteen patients with persisting acetabular dysplasia in the second and third decades. 2. The analysis suggests that for a good clinical result it is essential to create a relationship of the new outer acetabular lip to the original lip so that the CE angle is between 20 and 40 degrees and the roof angle is between 10 degrees below and 20 degrees above the horizontal. 3. This may be achieved by a pelvic osteotomy immediately above the joint capsule, angled 10 degrees upwards and inwards and displaced by 50 per cent of the pelvic thickness. 4. Details of the operative technique using a Smith-Petersen approach are presented

The hypothesis provides a theoretical justification for, and re-emphasises the practical importance of, close reduction and strict immobilisation in the treatment of fractures of the neck of the femur. It does not support the view that failure of union is caused by vascular damage at the time of the original injury. Unexpected failure of union after nailing is more likely caused by unrecognised imperfection of reduction and the acknowledged deficiencies of internal fixation. Attempts to improve results by passing the sartorius muscle around the fracture (Adams 1956), or by attaching muscle or joint capsule to the proximal fragment, have failed, because such soft tissues are swept off by the acetabular rim when the hip is flexed or medially rotated. Further work is required, both on the more detailed biochemistry of haemarthroses and on the practical and wider implications of the hypothesis

The significance of cobalt as a cause of symptoms after McKee hip arthroplasty is discussed. Seven patients are described in whom such arthroplasties became unsatisfactory after periods varying from nine months to four years. Six of these patients were cobalt-positive but nickel-and chrome-negative on patch testing. Macroscopic and histological necrosis of bone, muscle and joint capsule around the prostheses was found in five patients whose hips were explored. The symptoms were progressive pain, a feeling of instability, and in two cases spontaneous dislocation. Radiological features included acetabular fracture, bone resorption, loosening and dislocation of the prosthesis. Increased cobalt concentrations (determined by atomic absorption spectrophotometry) in the urine of four patients and in a variety of tissues in one patient are presented. Patch testing is recommended in the investigation of patients with troublesome McKee hip arthroplasties

The Chiari osteotomy and various shelf procedures are used to augment the weight-bearing area in dysplastic acetabula. The new articular surface derives by metaplasia from the acetabular rim and joint capsule, and is therefore of poorer quality than congruous hyaline cartilage. We reviewed 32 patients after augmentation procedures, using conventional radiographs and three-dimensional reconstruction from CT scans. We showed that Chiari osteotomy and shelf procedures generally achieve less than complete cover, especially over the posterolateral quadrant of the femoral head. Our results suggest that alternative methods which reorientate the whole of the acetabulum are the treatment of choice. Augmentation procedures remain as a salvage option when reorientation is inappropriate or the original hyaline cartilage surface is absent, as in subluxed joints with a secondary acetabulum. Computerised assessment is recommended before operation to assess existing cover and the possible extent of provision of new cover

An experimental model of osteoarthritis resulting from laxity of the joint was induced in eighteen mature dogs (at least two years old) by sectioning the anterior cruciate ligament of the right knee (stifle) with a stab incision, the left knee providing a control. A sham operation was also performed in three other dogs, in which a stab incision was made but the ligament left intact. The dogs were killed at various intervals from one to forty-eight weeks later. Morphological changes in bone, cartilage, synovial membrane and joint capsule were examined in all the joints and biochemical changes in the cartilage of three dogs killed after two, eight, and sixteen weeks. All the changes resulting from the operation progressed with time and became indistinguishable from those found in three dogs with natural osteoarthritis of the knee. There were no changes in the joints which had sham operations. As the time of onset is known, this experimental model in a larger species enables a study to be made of the biochemical as well as the morphological changes in the early stages of osteoarthritis

We analysed synovial fluid from 88 hips, 38 with osteoarthritis and 12 with well-functioning and 38 with loose hip prostheses. The levels of TNF-α, IL-1ß (71 hips) and IL-6 (45 hips) were measured using the ELISA technique. Joints with well-functioning or loose prostheses had significantly increased levels of TNF-α compared with those with osteoarthritis. Hips with aseptic loosening also had higher levels of IL-1ß but not of IL-6 compared with those without an implant. The levels of TNF-α and IL-1ß did not differ between hips with stable and loose prostheses. Higher levels of TNF-α were found in hips with bone resorption of type II and type III (Gustilo-Pasternak) compared with those with type-I loosening. The level of cytokines in joint fluid was not influenced by the time in situ of the implants or the age, gender or area of the osteolysis as measured on conventional radiographs. Our findings support the theory that macrophages in the joint capsule increase the production of TNF-α at an early phase probably because of particle load and in the absence of clinical loosening. Since TNF-α has an important role in the osteolytic process, the interfaces should be protected from penetration of joint fluid

We measured joint position sense in the knee by a new method which tests the proprioceptive contribution of the joint capsule and ligaments. The leg was supported on a splint, and held in several positions of flexion. The subjects' perception of the position was recorded on a visual analogue model and compared with the actual angle of flexion. Eighty-one normal and 45 osteoarthritic knees were examined, as were 10 knees with semi-constrained and 11 with hinged joint replacements. All were assessed with and without an elastic bandage around the knee. There was a steady decline in joint position sense with age in subjects with normal knees. Those with osteoarthritic knees had impaired joint position sense at all ages (p less than 0.001). Knee replacement improved the joint position sense slightly (p less than 0.02); semi-constrained replacement had a greater effect than hinged replacement. The effect of an elastic bandage in subjects with poor position sense was dramatic, improving accuracy by 40% (p less than 0.001). It is proposed that reduced proprioception in elderly and osteoarthritic subjects may be responsible for initiation or advancement of degeneration of the knee

The primary source for the blood supply of the head of the femur is the deep branch of the medial femoral circumflex artery (MFCA). In posterior approaches to the hip and pelvis the short external rotators are often divided. This can damage the deep branch and interfere with perfusion of the head. We describe the anatomy of the MFCA and its branches based on dissections of 24 cadaver hips after injection of neoprene-latex into the femoral or internal iliac arteries. The course of the deep branch of the MFCA was constant in its extracapsular segment. In all cases there was a trochanteric branch at the proximal border of quadratus femoris spreading on to the lateral aspect of the greater trochanter. This branch marks the level of the tendon of obturator externus, which is crossed posteriorly by the deep branch of the MFCA. As the deep branch travels superiorly, it crosses anterior to the conjoint tendon of gemellus inferior, obturator internus and gemellus superior. It then perforates the joint capsule at the level of gemellus superior. In its intracapsular segment it runs along the posterosuperior aspect of the neck of the femur dividing into two to four subsynovial retinacular vessels. We demonstrated that obturator externus protected the deep branch of the MFCA from being disrupted or stretched during dislocation of the hip in any direction after serial release of all other soft-tissue attachments of the proximal femur, including a complete circumferential capsulotomy. Precise knowledge of the extracapsular anatomy of the MFCA and its surrounding structures will help to avoid iatrogenic avascular necrosis of the head of the femur in reconstructive surgery of the hip and fixation of acetabular fractures through the posterior approach

1. Léri's pleonosteosis is characterised by broadening and deformity of the thumbs and great toes, flexion contracture of the interphalangeal joints, limited movement of other joints, and often a Mongoloid facies. Four such cases are described. 2. A review of the twenty reports in the literature, and the cases now described, shows that the deformities are due to capsular contracture rather than deformity of bone. 3. In one patient there was striking evidence of fibro-cartilaginous thickening of the anterior carpal ligaments. It is suggested that the primary pathological change in pleonosteosis may be in the joint capsules rather than in the epiphyses. 4. The patient with thickening of the anterior carpal ligaments had bilateral median palsy from carpal tunnel compression. 5. The causes of carpal tunnel compression of the median nerve are reviewed. Acute compression may be due not only to dislocation of the semilunar bone but to haemorrhage in the palm. Late compression by bone may occur twenty to fifty years after injury. Late compression without bone abnormality has been attributed to occupational stress, but it is suggested that pathological thickening of the anterior carpal ligament may be the cause. 6. The patient with pleonosteosis and bilateral median palsy had also bilateral Morton's metatarsalgia with large digital neuromata. 7. Plantar digital neuritis has already been shown to be an ischaemic nerve lesion preceded by degenerative changes in the digital artery. The significance of the fibrous tunnel through which the artery passes to reach the digital cleft is considered

We revised seven alumina-blasted cementless hip prostheses (Ti-alloy stems, cp Ti threaded sockets) with low- or high-carbon Co-alloy bearings at a mean of 20.1 months after implantation because of pain and loosening. Histological examination of the retrieved periprosthetic tissues from two cases in which the implant was stable and three in which the socket was loose showed macrophages with basophilic granules containing metal and alumina wear particles and lymph-cell infiltrates. In one of the two cases of stem loosening the thickened neocapsule also contained definite lymphatic follicles and gross lymphocyte/plasma-cell infiltrates. Spectrometric determination of the concentration of elements in periprosthetic tissues from six cases was compared with that of joint capsules from five control patients undergoing primary hip surgery. In the revisions the mean concentration of implant-relevant elements was 693.85 μg/g dry tissue. In addition to Cr (15.2%), Co (4.3%), and Ti (10.3%), Al was predominant (68.1%) and all concentrations were significantly higher (p < 0.001) than those in the control tissues. The annual rates of linear wear were calculated for six implants. The mean value was 11.1 μm (heads 6.25 μm, inserts 4.82 μm). SEM/EDXA showed numerous fine scratches and deep furrows containing alumina particles in loosened sockets, and stems showed contamination with adhering or impacted alumina particles of between 2 and 50 μm in size

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

After open reduction for developmental dysplasia of the hip (DDH), a pelvic or femoral osteotomy may be required to maintain a stable concentric reduction. We report the clinical and radiological outcome in 82 children (95 hips) with DDH treated by open reduction through an anterior approach in which a test of stability was used to assess the need for a concomitant osteotomy. The mean age at the time of surgery was 28 months (9 to 79) and at the latest follow-up, 17 years (12 to 25). All patients have been followed up until closure of the triradiate cartilage with a mean period of 15 years (8 to 23). At the time of open reduction before closure of the joint capsule, the position of maximum stability was assessed. A hip which required flexion with abduction for stability was considered to need an innominate osteotomy. If only internal rotation and abduction were required, an upper femoral derotational and varus osteotomy was carried out. For a ‘double-diameter’ acetabulum with anterolateral deficiency, a Pemberton-type osteotomy was used. A hip which was stable in the neutral position required no concomitant osteotomy. Overall, 86% of the patients have had a satisfactory radiological outcome (Severin groups I and II) with an incidence of 7% of secondary procedures for persistent dysplasia including one hip which redislocated. The results were better (p = 0.04) in children under the age of two years. Increased leg length on the affected side was associated with poor acetabular development and recurrence of joint dysplasia (p = 0.01). The incidence of postoperative avascular necrosis was 7%. In a further 18%, premature physeal arrest was noted during the adolescent growth spurt (Kalamchi-MacEwen types II and III). Both of these complications were also associated with recurrence of joint dysplasia (p = 0.01). Studies with a shorter follow-up are therefore likely to underestimate the proportion of poor radiological results

Aims

The patient-acceptable symptom state (PASS) is a level of wellbeing, which is measured by the patient. The aim of this study was to determine if the proportion of patients who achieved an acceptable level of function (PASS) after medial unicompartmental knee arthroplasty (UKA) was different based on the status of the anterior cruciate ligament (ACL) at the time of surgery.

Aims

Ultrasound (US)-guided injections are widely used in patients with conditions of the shoulder in order to improve their accuracy. However, the clinical efficacy of US-guided injections compared with blind injections remains controversial. The aim of this study was to compare the accuracy and efficacy of US-guided compared with blind corticosteroid injections into the glenohumeral joint in patients with primary frozen shoulder (FS).

The experiments were performed to answer three main questions. These and our answers may be summarised as follows. What is the precise mechanism of healing of a raw bony surface in a joint? What cells are involved? Where do they originate?—In all the implant experiments and in the control series the fundamental mechanism of healing was similar. 1. A massive proliferation of fibroblasts occurred from the cut periosteum, from the cut joint capsule, and to a lesser extent from the medullary canal. 2. Fibroblasts grew centripetally in the first few weeks after operation, attempting to form a "fibroblast cap" to the cut bone end. 3. Fibroblasts of this cap near the cut bone spicules metamorphosed to become prechondroblasts, chondroblasts laying down cartilage matrix, and hypertrophied (alkaline phosphatase-secreting) chondrocytes lying in a calcified matrix. 4. This calcified cartilage matrix was invaded by dilated capillaries probably bearing osteoblasts which laid down perivascular (endochondral) bone. 5. Some of the cells of projecting bone spicules died and their matrix was eroded in the presence of many osteoclasts. 6. In the control experiments of simple excision of the radial head new bone was produced at the periphery only by processes (3) and (4). This sealed off the underlying peripheral cortical bone from the superficially placed peripheral articular surface of fibrocartilage. At about a year from operation the central portion of the articular surface was still formed of bare bone, or of bone spicules covered by a thin layer of irregularly arranged collagen fibres. The opposite capitular articular cartilage was badly eroded. Does the introduction of a dead cartilage implant over the raw bone end affect in any way the final constitution of the new articular surface?—In the implant experiments the new bone produced by processes (3) and (4) formed, after about a year, a complete cortical plate which entirely sealed off the cut end of the radius and left a superficially placed articular covering of smooth fibrocartilage, closely resembling a normal joint surface. The opposite capitular articular surface was normal. What is the final fate of such an implant?—Whale cartilage implants underwent replacement by fibroblasts and collagen fibres, and took about nine months to disappear. The cartilage of fixed autotransplants and homotransplants underwent similar gradual replacement, and took about the same time in each case. The dead bone, implanted in association with the cartilage in both cases, acted as a nidus for hyaline cartilage production by chondrocytes derived from fibroblasts. This cartilage underwent endochondral ossification. This observation suggests that induction by non-cellular osseous material is a factor in chondrification and ossification. All the implants functioned as temporary articular menisci or in some cases as temporary radial articular surfaces. They were always replaced by a permanent fibrocartilaginous meniscus, or a fibrocartilaginous articular surface. An implant did, in fact, always act as a temporary protecting cap and mould for the subjacent growth offibroblasts which was necessary for the production of a satisfactory new joint surface

Aims

Optimal exposure through the direct anterior approach (DAA) for total hip arthroplasty (THA) conducted on a regular operating theatre table is achieved with a standardized capsular releasing sequence in which the anterior capsule can be preserved or resected. We hypothesized that clinical outcomes and implant positioning would not be different in case a capsular sparing (CS) technique would be compared to capsular resection (CR).

Aims

Surgical treatment of hip fracture is challenging; the bone is porotic and fixation failure can be catastrophic. Novel implants are available which may yield superior clinical outcomes. This study compared the clinical effectiveness of the novel X-Bolt Hip System (XHS) with the sliding hip screw (SHS) for the treatment of fragility hip fractures.

Aims

Vitamin E-infused highly cross-linked polyethylene (E1) has recently been introduced in total knee arthroplasty (TKA). An in vitro wear simulator study showed that E1 reduced polyethylene wear. However there is no published information regarding in vivo wear. Previous reports suggest that newly introduced materials which reduce in vitro polyethylene wear do not necessarily reduce in vivo polyethylene wear. To assist in the evaluation of the newly introduced material before widespread use, we established an in vivo polyethylene wear particle analysis for TKA. The aim of this study was to compare in vivo polyethylene wear particle generation between E1 and conventional polyethylene (ArCom) in TKA.

Aims

Options for the treatment of intra-articular ligament injuries are limited, and insufficient ligament reconstruction can cause painful joint instability, loss of function, and progressive development of degenerative arthritis. This study aimed to assess the capability of a biologically enhanced matrix material for ligament reconstruction to withstand tensile forces within the joint and enhance ligament regeneration needed to regain joint function.

Aims

Inadvertent soft tissue damage caused by the oscillating saw during total knee arthroplasty (TKA) occurs when the sawblade passes beyond the bony boundaries into the soft tissue. The primary objective of this study is to assess the risk of inadvertent soft tissue damage during jig-based TKA by evaluating the excursion of the oscillating saw past the bony boundaries. The second objective is the investigation of the relation between this excursion and the surgeon’s experience level.

Aims

Responsiveness and ceiling effects are key properties of an outcome score. No such data have been reported for the original English version of the International Hip Outcome Tool 12 (iHOT-12) at a follow-up of more than four months. The aim of this study was to identify the responsiveness and ceiling effects of the English version iHOT-12 in a series of patients undergoing hip arthroscopy for intra-articular hip pathology at a minimum of one year postoperatively.

In this review, we discuss the evidence for patients returning to sport after hip arthroplasty. This includes the choices regarding level of sporting activity and revision or complications, the type of implant, fixation and techniques of implantation, and how these choices relate to health economics. It is apparent that despite its success over six decades, hip arthroplasty has now evolved to accommodate and support ever-increasing patient demands and may therefore face new challenges.

Cite this article: Bone Joint J 2020;102-B(6):661–663.

Aims

The aim of this study was to analyze the association between the shape of the distal radius sigmoid notch and triangular fibrocartilage complex (TFCC) foveal tear.

Deep gluteal syndrome is an increasingly recognized disease entity, caused by compression of the sciatic or pudendal nerve due to non-discogenic pelvic lesions. It includes the piriformis syndrome, the gemelli-obturator internus syndrome, the ischiofemoral impingement syndrome, and the proximal hamstring syndrome. The concept of the deep gluteal syndrome extends our understanding of posterior hip pain due to nerve entrapment beyond the traditional model of the piriformis syndrome. Nevertheless, there has been terminological confusion and the deep gluteal syndrome has often been undiagnosed or mistaken for other conditions. Careful history-taking, a physical examination including provocation tests, an electrodiagnostic study, and imaging are necessary for an accurate diagnosis.

After excluding spinal lesions, MRI scans of the pelvis are helpful in diagnosing deep gluteal syndrome and identifying pathological conditions entrapping the nerves. It can be conservatively treated with multidisciplinary treatment including rest, the avoidance of provoking activities, medication, injections, and physiotherapy.

Endoscopic or open surgical decompression is recommended in patients with persistent or recurrent symptoms after conservative treatment or in those who may have masses compressing the sciatic nerve.

Many physicians remain unfamiliar with this syndrome and there is a lack of relevant literature. This comprehensive review aims to provide the latest information about the epidemiology, aetiology, pathology, clinical features, diagnosis, and treatment.

Cite this article: Bone Joint J 2020;102-B(5):556–567.

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We report the natural course of Baker’s cysts following total knee arthroplasty (TKA) at short- and mid-term follow-up.

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The purpose of this study was to report the long-term results of extendable endoprostheses of the humerus in children after the resection of a bone sarcoma.

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The aim of this study was to clarify the factors that predict the development of avascular necrosis (AVN) of the femoral head in children with a fracture of the femoral neck.