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.

Aims

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

Aims

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.

Aims

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.

Aim

Mesenchymal stem cells (MSCs) have several properties that may support their use as an early treatment option for osteoarthritis (OA). This study investigated the role of multiple injections of allogeneic bone marrow-derived stem cells (BMSCs) to alleviate the progression of osteoarthritic changes in the various structures of the mature rabbit knee in an anterior cruciate ligament (ACL)-deficient OA model.

Aims

Increasingly, patients with bilateral hip arthritis wish to undergo staged total hip arthroplasty (THA). With the rise in demand for arthroplasty, perioperative risk assessment and counselling is crucial for shared decision making. However, it is unknown if complications that occur after a unilateral hip arthroplasty predict complications following surgery of the contralateral hip.

Abstract

Nerve transfer has become a common and often effective reconstructive strategy for proximal and complex peripheral nerve injuries of the upper limb. This case-based discussion explores the principles and potential benefits of nerve transfer surgery and offers in-depth discussion of several established and valuable techniques including: motor transfer for elbow flexion after musculocutaneous nerve injury, deltoid reanimation for axillary nerve palsy, intrinsic re-innervation following proximal ulnar nerve repair, and critical sensory recovery despite non-reconstructable median nerve lesions.

Aims

The objectives of this study were to compare postoperative pain, analgesia requirements, inpatient functional rehabilitation, time to hospital discharge, and complications in patients undergoing conventional jig-based unicompartmental knee arthroplasty (UKA) versus robotic-arm assisted UKA.

Aims

Periacetabular osteotomy is an effective way of treating symptomatic hip dysplasia. We describe a new minimally invasive technique using a modification of the Smith-Peterson approach.

We performed a prospective, longitudinal cohort study to assess for any compromise in acetabular correction when using this approach, and to see if the procedure would have a higher complication rate than that quoted in the literature for other approaches. We also assessed for any improvement in functional outcome.

Aims

This study describes and compares the operative management and outcomes in a consecutive case series of patients with dislocated hemiarthroplasties of the hip, and compares outcomes with those of patients not sustaining a dislocation.

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 morphometry of the distal femur was largely studied to improve bone-implant fit in total knee arthroplasty (TKA), but little is known about the asymmetry of the posterior condyles. This study aimed to investigate the dimensions of the posterior condyles and the influence of externally rotating the femoral component on potential prosthetic overhang or under-coverage.

In this in vitro study of the hip joint we examined which soft tissues act as primary and secondary passive rotational restraints when the hip joint is functionally loaded. A total of nine cadaveric left hips were mounted in a testing rig that allowed the application of forces, torques and rotations in all six degrees of freedom. The hip was rotated throughout a complete range of movement (ROM) and the contributions of the iliofemoral (medial and lateral arms), pubofemoral and ischiofemoral ligaments and the ligamentum teres to rotational restraint was determined by resecting a ligament and measuring the reduced torque required to achieve the same angular position as before resection. The contribution from the acetabular labrum was also measured. Each of the capsular ligaments acted as the primary hip rotation restraint somewhere within the complete ROM, and the ligamentum teres acted as a secondary restraint in high flexion, adduction and external rotation. The iliofemoral lateral arm and the ischiofemoral ligaments were primary restraints in two-thirds of the positions tested. Appreciation of the importance of these structures in preventing excessive hip rotation and subsequent impingement/instability may be relevant for surgeons undertaking both hip joint preserving surgery and hip arthroplasty.

Cite this article: Bone Joint J 2015; 97-B:484–91.

Aims

The purpose of this current multicentre study is to analyse the presence of alpha-defensin proteins in synovial fluid using the Synovasure lateral flow device and to determine its diagnostic reliability and accuracy compared with the prosthetic joint infection (PJI) criteria produced by the Musculoskeletal Infection Society (MSIS).

Aims

Several studies have reported the safety and efficacy of subcapital re-alignment for patients with slipped capital femoral epiphysis (SCFE) using surgical dislocation of the hip and an extended retinacular flap. Instability of the hip and dislocation as a consequence of this surgery has only recently gained attention. We discuss this problem with some illustrative cases.

Aims

We aimed to quantify the relative contributions of the medial femoral circumflex artery (MFCA) and lateral femoral circumflex artery (LFCA) to the arterial supply of the head and neck of the femur.

Aims

The aim of this consensus was to develop a definition of post-operative fibrosis of the knee.

Our understanding of the origin of hip pain in degenerative disorders of the hip, including primary osteoarthritis, avascular necrosis and femoroacetabular impingement (FAI), is limited. We undertook a histological investigation of the nociceptive innervation of the acetabular labrum, ligamentum teres and capsule of the hip, in order to prove pain- and proprioceptive-associated marker expression. These structures were isolated from 57 patients who had undergone elective hip surgery (44 labral samples, 33 ligamentum teres specimens, 34 capsular samples; in 19 patients all three structures were harvested). A total of 15 000 histological sections were prepared that were investigated immunohistochemically for the presence of protein S-100, 68 kDa neurofilament, neuropeptide Y, nociceptin and substance P. The tissues were evaluated in six representative areas.

Within the labrum, pain-associated free nerve ending expression was located predominantly at its base, decreasing in the periphery. In contrast, the distribution within the ligamentum teres showed a high local concentration in the centre. The hip capsule had an almost homogeneous marker expression in all investigated areas.

This study showed characteristic distribution profiles of nociceptive and pain-related nerve fibres, which may help in understanding the origin of hip pain.

Cite this article: Bone Joint J 2013;95-B:770–6.

Reported rates of dislocation in hip hemiarthroplasty (HA) for the treatment of intra-capsular fractures of the hip, range between 1% and 10%. HA is frequently performed through a direct lateral surgical approach. The aim of this study is to determine the contribution of the anterior capsule to the stability of a cemented HA through a direct lateral approach.

A total of five whole-body cadavers were thawed at room temperature, providing ten hip joints for investigation. A Thompson HA was cemented in place via a direct lateral approach. The cadavers were then positioned supine, both knee joints were disarticulated and a digital torque wrench was attached to the femur using a circular frame with three half pins. The wrench applied an external rotation force with the hip in extension to allow the hip to dislocate anteriorly. Each hip was dislocated twice; once with a capsular repair and once without repairing the capsule. Stratified sampling ensured the order in which this was performed was alternated for the paired hips on each cadaver.

Comparing peak torque force in hips with the capsule repaired and peak torque force in hips without repair of the capsule, revealed a significant difference between the ‘capsule repaired’ (mean 22.96 Nm, standard deviation (sd) 4.61) and the ‘capsule not repaired’ group (mean 5.6 Nm, sd 2.81) (p < 0.001). Capsular repair may help reduce the risk of hip dislocation following HA.

Cite this article: Bone Joint J 2015;97-B:141–4.

The acetabular labrum is a soft-tissue structure which lines the acetabular rim of the hip joint. Its role in hip joint biomechanics and joint health has been of particular interest over the past decade. In normal hip joint biomechanics, the labrum is crucial in retaining a layer of pressurised intra-articular fluid for joint lubrication and load support/distribution. Its seal around the femoral head is further regarded as a contributing to hip stability through its suction effect. The labrum itself is also important in increasing contact area thereby reducing contact stress. Given the labrum’s role in normal hip joint biomechanics, surgical techniques for managing labral damage are continuously evolving as our understanding of its anatomy and function continue to progress. The current paper aims to review the anatomy and biomechanical function of the labrum and how they are affected by differing surgical techniques.

Take home message: The acetabular labrum plays a critical role in hip function and maintaining and restoring its function during surgical intervention remain an essential goal.

Cite this article: Bone Joint J 2016;98-B:730–5.

A small proportion of children with Gartland type III supracondylar humeral fracture (SCHF) experience troubling limited or delayed recovery after operative treatment. We hypothesised that the fracture level relative to the isthmus of the humerus would affect the outcome.

We retrospectively reviewed 230 children who underwent closed reduction and percutaneous pinning (CRPP) for their Gartland type III SCHFs between March 2003 and December 2012. There were 144 boys and 86 girls, with the mean age of six years (1.1 to 15.2). The clinico-radiological characteristics and surgical outcomes (recovery of the elbow range of movement, post-operative angulation, and the final Flynn grade) were recorded. Multivariate analysis was employed to identify prognostic factors that influenced outcome, including fracture level. Multivariate analysis revealed that a fracture below the humeral isthmus was significantly associated with poor prognosis in terms of the range of elbow movement (p < 0.001), angulation (p = 0.001) and Flynn grade (p = 0.003). Age over ten years was also a poor prognostic factor for recovery of the range of elbow movement (p = 0.027).

This is the first study demonstrating a subclassification system of Gartland III fractures with prognostic significance. This will guide surgeons in peri-operative planning and counselling as well as directing future research aimed at improving outcomes.

Cite this article: Bone Joint J 2015;97-B:134–40.

Aims

The primary aim of this study was to investigate the effect of an enhanced recovery program (ERP) on the short-term functional outcome after total hip arthroplasty (THA). Secondary outcomes included its effect on rates of dislocation and mortality.

Slipped upper femoral epiphysis (SUFE) is the most common hip disorder to affect adolescents. Controversy exists over the optimal treatment of severe slips, with a continuing debate between in situ fixation versus corrective surgery. We present our experience in a series of 57 patients presenting with severe unilateral SUFE (defined > 50°) managed with a subcapital cuneiform osteotomy.

Between 2001 and 2011, 57 patients (35 male, 22 female) with a mean age of 13.1 years (9.6 to 20.3, SD 2.3) were referred to our tertiary referral institution with a severe slip. The affected limb was rested in slings and springs before corrective surgery which was performed via an anterior Smith-Petersen approach. Radiographic analysis confirmed an improvement in mean head–shaft slip angle from 53.8^o (standard deviation (sd) 3.2) pre-operatively to 9.1^o (sd 3.1) post-operatively, with minimal associated femoral neck shortening. In total 50 (88%) patients were complication free at a mean follow-up of seven years (2.8 to 13.9 years, sd 3). Their mean Oxford hip score was 44 (37 to 48) and median visual analogue pain score was 0 out of 10 (interquartile range 0 to 4). A total of six patients (10.5%) developed avascular necrosis requiring further surgery and one (1.8%) patient developed chondrolysis but declined further intervention.

This is a technically demanding operation with variable outcomes reported in the literature. We have demonstrated good results in our tertiary centre.

Cite this article: Bone Joint J 2015;97-B:1718–25.

In this paper we propose a new classification of neurogenic peri-articular heterotopic ossification (HO) of the hip based on three-dimensional (3D) CT, with the aim of improving pre-operative planning for its excision.

A total of 55 patients (73 hips) with clinically significant HO after either traumatic brain or spinal cord injury were assessed by 3D-CT scanning, and the results compared with the intra-operative findings.

At operation, the gross pathological anatomy of the HO as identified by 3D-CT imaging was confirmed as affecting the peri-articular hip muscles to a greater or lesser extent. We identified seven patterns of involvement: four basic (anterior, medial, posterior and lateral) and three mixed (anteromedial, posterolateral and circumferential). Excellent intra- and inter-observer agreement, with kappa values > 0.8, confirmed the reproducibility of the classification system.

We describe the different surgical approaches used to excise the HO which were guided by the 3D-CT findings. Resection was always successful.

3D-CT imaging, complemented in some cases by angiography, allows the surgeon to define the 3D anatomy of the HO accurately and to plan its surgical excision with precision.

Cite this article: Bone Joint J 2015; 97-B:899–904.

The peri-prosthetic tissue response to wear debris is complex and influenced by various factors including the size, area and number of particles. We hypothesised that the ‘biologically active area’ of all metal wear particles may predict the type of peri-prosthetic tissue response.

Peri-prosthetic tissue was sampled from 21 patients undergoing revision of a small diameter metal-on-metal (MoM) total hip arthroplasty (THA) for aseptic loosening. An enzymatic protocol was used for tissue digestion and scanning electron microscope was used to characterise particles. Equivalent circle diameters and particle areas were calculated. Histomorphometric analyses were performed on all tissue specimens. Aspirates of synovial fluid were collected for analysis of the cytokine profile analysis, and compared with a control group of patients undergoing primary THA (n = 11) and revision of a failed ceramic-on-polyethylene arthroplasty (n = 6).

The overall distribution of the size and area of the particles in both lymphocyte and non-lymphocyte-dominated responses were similar; however, the subgroup with lymphocyte-dominated peri-prosthetic tissue responses had a significantly larger total number of particles.

14 cytokines (interleukin (IL)-1ß, IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, IL-17, interferon (IFN)-γ, and IFN-gamma-inducible protein 10), chemokines (macrophage inflammatory protein (MIP)-1α and MIP-1ß), and growth factors (granulocyte macrophage colony stimulating factor (GM-CSF) and platelet derived growth factor) were detected at significantly higher levels in patients with metal wear debris compared with the control group.

Significantly higher levels for IL-1ß, IL-5, IL-10 and GM-CSF were found in the subgroup of tissues from failed MoM THAs with a lymphocyte-dominated peri-prosthetic response compared with those without this response.

These results suggest that the ‘biologically active area’ predicts the type of peri-prosthetic tissue response. The cytokines IL-1ß, IL-5, IL-10, and GM-CSF are associated with lymphocyte-dominated tissue responses from failed small-diameter MoM THA.

Cite this article: Bone Joint J 2015;97-B:917–23.

Successful management of late presenting hip dislocation in childhood is judged by the outcome not just at skeletal maturity but well beyond into adulthood and late middle age. This review considers different methods of treatment and looks critically at the handful of studies reporting long-term follow-up after successful reduction.

Cite this article: Bone Joint J 2015;97-B:729–33.

The modified Smith–Petersen and Kocher–Langenbeck approaches were used to expose the lateral cutaneous nerve of the thigh and the femoral, obturator and sciatic nerves in order to study the risk of injury to these structures during the dissection, osteotomy, and acetabular reorientation stages of a Bernese peri-acetabular osteotomy.

Injury of the lateral cutaneous nerve of thigh was less likely to occur if an osteotomy of the anterior superior iliac spine had been carried out before exposing the hip.

The obturator nerve was likely to be injured during unprotected osteotomy of the pubis if the far cortex was penetrated by > 5 mm. This could be avoided by inclining the osteotome 45° medially and performing the osteotomy at least 2 cm medial to the iliopectineal eminence.

The sciatic nerve could be injured during the first and last stages of the osteotomy if the osteotome perforated the lateral cortex of ischium and the ilio-ischial junction by > 10 mm.

The femoral nerve could be stretched or entrapped during osteotomy of the pubis if there was significant rotational or linear displacement of the acetabulum. Anterior or medial displacement of < 2 cm and lateral tilt (retroversion) of < 30° were safe margins. The combination of retroversion and anterior displacement could increase tension on the nerve.

Strict observation of anatomical details, proper handling of the osteotomes and careful manipulation of the acetabular fragment reduce the neurological complications of Bernese peri-acetabular osteotomy.

Cite this article: Bone Joint J 2015;97-B:636–41.

We dissected 20 cadaver hips in order to investigate the anatomy and excursion of the trochanteric muscles in relation to the posterior approach for total hip replacement. String models of each muscle were created and their excursion measured while the femur was moved between its anatomical position and the dislocated position. The position of the hip was determined by computer navigation.

In contrast to previous studies which showed a separate insertion of piriformis and obturator internus, our findings indicated that piriformis inserted onto the superior and anterior margins of the greater trochanter through a conjoint tendon with obturator internus, and had connections to gluteus medius posteriorly. Division of these connections allowed lateral mobilisation of gluteus medius with minimal retraction. Analysis of the excursion of these muscles revealed that positioning the thigh for preparation of the femur through this approach elongated piriformis to a maximum of 182%, obturator internus to 185% and obturator externus to 220% of their resting lengths, which are above the thresholds for rupture of these muscles.

Our findings suggested that gluteus medius may be protected from overstretching by release of its connection with the conjoint tendon. In addition, failure to detach piriformis or the obturators during a posterior approach for total hip replacement could potentially produce damage to these muscles because of over-stretching, obturator externus being the most vulnerable.

We investigated the incidence and risk factors for the development of avascular necrosis (AVN) of the femoral head in the course of treatment of children with cerebral palsy (CP) and dislocation of the hip. All underwent open reduction, proximal femoral and Dega pelvic osteotomy. The inclusion criteria were: a predominantly spastic form of CP, dislocation of the hip (migration percentage, MP > 80%), Gross Motor Function Classification System, (GMFCS) grade IV to V, a primary surgical procedure and follow-up of > one year.

There were 81 consecutive children (40 girls and 41 boys) in the study. Their mean age was nine years (3.5 to 13.8) and mean follow-up was 5.5 years (1.6 to 15.1). Radiological evaluation included measurement of the MP, the acetabular index (AI), the epiphyseal shaft angle (ESA) and the pelvic femoral angle (PFA). The presence and grade of AVN were assessed radiologically according to the Kruczynski classification.

Signs of AVN (grades I to V) were seen in 79 hips (68.7%). A total of 23 hips (18%) were classified between grades III and V.

Although open reduction of the hip combined with femoral and Dega osteotomy is an effective form of treatment for children with CP and dislocation of the hip, there were signs of avascular necrosis in about two-thirds of the children. There was a strong correlation between post-operative pain and the severity of the grade of AVN.

Cite this article: Bone Joint J 2015;97-B:270–6.

We investigated the incidence of soft-tissue lesions after small head metal-on-metal total hip replacement (MoM THR). Between December 1993 and May 1999, 149 patients (195 hips) underwent primary cementless MoM THR.

During the follow-up period, three patients (five THRs) died and eight patients (14 THRs) were lost to follow-up. We requested that all patients undergo CT evaluation. After exclusion of five patients (six THRs) who had undergone a revision procedure, and 22 (28 THRs) who were unwilling to take part in this study, 111 patients (142 THRs) were evaluated. There were 63 men (88 THRs) and 48 women (54 THRs) with a mean age of 45.7 years (37 to 56) at the time of surgery. The mean follow-up was 15.4 years (13 to 19). A soft-tissue lesion was defined as an abnormal peri-prosthetic collection of fluid, solid lesion or asymmetrical soft-tissue mass.

At final follow-up, soft-tissue lesions were found in relation to 28 THRs (19.7%), including 25 solid and three cystic lesions. They were found in 20 men and eight women; 26 lesions were asymptomatic and two were symptomatic. The mean maximal diameter of the soft-tissue lesion was 42.3 mm (17 to 135). The relatively high rate of soft-tissue lesions observed with small head MoM THR remains a concern.

Cite this article: Bone Joint J 2014;96-B:1594–9.

We describe a new surgical technique for the treatment of lacerations of the extensor tendon in zone I, which involves a tenodesis using a length of palmaris longus tendon one-quarter of its width. After exposing the dorsal aspect of the distal interphalangeal joint and harvesting the tendon, a 1.5 mm drill bit is passed through the insertion of the extensor tendon into the distal phalanx where it penetrates through the skin of the pulp of the digit. The palmaris longus tendon is threaded through the drill hole from dorsal to ventral and the ventral end is tied in a simple knot and trimmed. The palmaris longus tendon is then sutured to the extensor tendon close to its insertion, and also at the middle of the middle phalanx.

The operation was undertaken on 67 patients: 27 with an acute injury and 40 patients with a chronic mallet deformity. One finger (or the thumb) was involved in each patient. At a mean follow-up of 12 months (6 to 18), 66 patients (98.5%) received excellent or good results according to both the American Society for Surgery of the Hand (ASSH) classification and Miller’s classification.

Tenodesis using palmaris longus tendon after complete division of an extensor tendon in zone 1 is a reliable form of treatment for isolated acute or chronic ruptures.

Cartilage defects of the hip cause significant pain and may lead to arthritic changes that necessitate hip replacement. We propose the use of fresh osteochondral allografts as an option for the treatment of such defects in young patients. Here we present the results of fresh osteochondral allografts for cartilage defects in 17 patients in a prospective study. The underlying diagnoses for the cartilage defects were osteochondritis dissecans in eight and avascular necrosis in six. Two had Legg-Calve-Perthes and one a femoral head fracture. Pre-operatively, an MRI was used to determine the size of the cartilage defect and the femoral head diameter. All patients underwent surgical hip dislocation with a trochanteric slide osteotomy for placement of the allograft. The mean age at surgery was 25.9 years (17 to 44) and mean follow-up was 41.6 months (3 to 74). The mean Harris hip score was significantly better after surgery (p < 0.01) and 13 patients had fair to good outcomes. One patient required a repeat allograft, one patient underwent hip replacement and two patients are awaiting hip replacement. Fresh osteochondral allograft is a reasonable treatment option for hip cartilage defects in young patients.

Cite this article: Bone Joint J 2014;96-B(11 Supple A):11–16.

Between 2002 and 2008, 130 consecutive ankles were replaced with an hydroxyapatite (HA) and titanium-HA-coated Ankle Evolutive System total ankle prosthesis. Plain radiographs were analysed by two independent observers. Osteolytic lesions were classified by their size and location, with cavities > 10 mm in diameter considered to be ‘marked’. CT scanning was undertaken in all patients with marked osteolysis seen on the plain radiographs.

Osteolytic lesions were seen on the plain films in 48 (37%) and marked lesions in 27 (21%) ankles. The risk for osteolysis was found to be 3.1 (95% confidence interval 1.6 to 5.9) times higher with implants with Ti-HA porous coating.

Care should be taken with ankle arthroplasty until more is known about the reasons for these severe osteolyses.

The aim of this study was to determine whether an osteoplasty of the femoral neck performed at the same time as an intertrochanteric Imhäuser osteotomy led to an improved functional outcome or increased morbidity. A total of 20 hips in 19 patients (12 left, 8 right, 13 male, 6 female), who underwent an Imhäuser intertrochanteric osteotomy following a slipped capital femoral epiphysis were assessed over an eight-year period. A total of 13 hips in 13 patients had an osteoplasty of the femoral neck at the same time. The remaining six patients (seven hips) had intertrochanteric osteotomy alone. The mean age was 15.3 years (13 to 20) with a mean follow-up of 57.8 months (15 to 117); 19 of the slips were severe (Southwick grade III) and one was moderate (grade II), with a mean slip angle of 65.3° (50° to 80°); 17 of the slips were stable and three unstable at initial presentation. The mean Non-Arthritic Hip Scores (NAHS) in patients who underwent osteoplasty was 91.7 (76.3 to 100) and the mean NAHS in patients who did not undergo osteoplasty was 76.6 (41.3 to 100) (p = 0.056). Two patients required a subsequent arthroplasty and neither of these patients had an osteoplasty. No hips developed osteonecrosis or chondrolysis, and there was no increase in complications related to the osteoplasty. We recommend that for patients with a slipped upper femoral epiphysis undergoing an intertrochanteric osteotomy, the addition of an osteoplasty of the femoral neck should be considered.

Cite this article: Bone Joint J 2014;96-B:1119–23.

We have assessed the proximal capsular extension of the ankle joint in 18 patients who had a contrast-enhanced MRI ankle arthrogram in order to delineate the capsular attachments.

We noted consistent proximal capsular extensions anterior to the distal tibia and in the tibiofibular recess. The mean capsular extension anterior to the distal tibia was 9.6 mm (4.9 to 27.0) proximal to the anteroinferior tibial margin and 3.8 mm (−2.1 to 9.3) proximal to the dome of the tibial plafond. In the tibiofibular recess, the mean capsular extension was 19.2 mm (12.7 to 38.0) proximal to the anteroinferior tibial margin and 13.4 mm (5.8 to 20.5) proximal to the dome of the tibial plafond.

These areas of proximal capsular extensions run the risk of being traversed during the insertion of finewires for the treatment of fractures of the distal tibia. Surgeons using these techniques should be aware of this anatomy in order to minimise the risk of septic arthritis.

There have been differing descriptions of the anterolateral structures of the knee, and not all have been named or described clearly. The aim of this study was to provide a clear anatomical interpretation of these structures. We dissected 40 fresh-frozen cadaveric knees to view the relevant anatomy and identified a consistent structure in 33 knees (83%); we termed this the anterolateral ligament of the knee. This structure passes antero-distally from an attachment proximal and posterior to the lateral femoral epicondyle to the margin of the lateral tibial plateau, approximately midway between Gerdy’s tubercle and the head of the fibula. The ligament is superficial to the lateral (fibular) collateral ligament proximally, from which it is distinct, and separate from the capsule of the knee. In the eight knees in which it was measured, we observed that the ligament was isometric from 0° to 60° of flexion of the knee, then slackened when the knee flexed further to 90° and was lengthened by imposing tibial internal rotation.

Cite this article: Bone Joint J 2014;96-B:325–31.

We retrospectively reviewed the outcomes of 33 consecutive patients who had undergone an extra-articular, total or partial scapulectomy for a malignant tumour of the shoulder girdle between 1 July 2001 and 30 September 2013. Of these, 26 had tumours which originated in the scapula or the adjacent soft tissue and underwent a classic Tikhoff–Linberg procedure, while seven with tumours arising from the proximal humerus were treated with a modified Tikhoff-Linberg operation. We used a Ligament Advanced Reinforcement System for soft-tissue reconstruction in nine patients, but not in the other 24.

The mean Musculoskeletal Tumor Society score (MSTS) was 17.6 (95% confidence interval (CI) 15.9 to 19.4); 17.6 (95% CI 15.5 to 19.6) after the classic Tikhoff–Linberg procedure and 18.1 (95% CI 13.8 to 22.3) after the modified Tikhoff–Linberg procedure. Patients who had undergone a LARS soft-tissue reconstruction had a mean score of 18.6 (95% (CI) 13.9 to 22.4) compared with 17.2 (95% CI 15.5 to 19.0) for those who did not.

The Tikhoff–Linberg procedure is a useful method for wide resection of a malignant tumour of the shoulder girdle which helps to preserve hand and elbow function. The method of soft-tissue reconstruction has no effect on functional outcome.

Cite this article: Bone Joint J 2014;96-B:684–90.

Correction of valgus deformity of the hindfoot using a medial approach for a triple fusion has only recently been described for patients with tight lateral soft tissues which would be compromised using the traditional lateral approach. We present a series of eight patients with fixed valgus deformity of the hindfoot who had correction by hindfoot fusion using this approach.

In addition, we further extended the indications to allow concomitant ankle fusion. The medial approach allowed us to excise medial ulcers caused by the prominent medial bony structures, giving simultaneous correction of the deformity and successful internal fixation.

We had no problems with primary wound healing and experienced no subsequent infection or wound breakdown. From a mean fixed valgus deformity of 58.8° (45° to 66°) pre-operatively, we achieved a mean post-operative valgus angulation of 13.6° (7° to 23°). All the feet were subsequently accommodated in shoes. The mean time to arthrodesis was 5.25 months (3 to 9).

We therefore recommend the medial approach for the correction of severe fixed valgus hindfoot deformities.

Neurogenic myositis ossificans is a disabling condition affecting the large joints of patients with severe post-traumatic impairment of the central nervous system. It can result in ankylosis of the joint and vascular or neural compression. Surgery may be hazardous with potential haemorrhage, neurovascular injury, iatrogenic fracture and osteochondral injury. We undertook pre-operative volumetric CT assessment of 45 ankylosed hips with neurogenic myositis ossificans which required surgery. Helical CT with intravenous contrast, combined with two- and three-dimensional surface reconstructions, was the only pre-operative imaging procedure. This gave good differentiation of the heterotopic bone from the adjacent vessels. We established that early surgery, within 24 months of injury, was neither complicated by peri-operative fracture nor by the early recurrence of neurogenic myositis ossificans. Surgical delay was associated with a loss of joint space and a greater degree of bone demineralisation. Enhanced volumetric CT is an excellent method for the pre-operative assessment of neurogenic myositis ossificans and correlates well with the operative findings.

Total hip replacement (THR) after acetabular fracture presents unique challenges to the orthopaedic surgeon. The majority of patients can be treated with a standard THR, resulting in a very reasonable outcome. Technical challenges however include infection, residual pelvic deformity, acetabular bone loss with ununited fractures, osteonecrosis of bone fragments, retained metalwork, heterotopic ossification, dealing with the sciatic nerve, and the difficulties of obtaining long-term acetabular component fixation. Indications for an acute THR include young patients with both femoral head and acetabular involvement with severe comminution that cannot be reconstructed, and the elderly, with severe bony comminution. The outcomes of THR for established post-traumatic arthritis include excellent pain relief and functional improvements. The use of modern implants and alternative bearing surfaces should improve outcomes further.

Cite this article: Bone Joint J 2013;95-B, Supple A:11–16.

Intertrochanteric osteotomy may postpone the need for total hip replacement (THR). In young patients with an acquired deformity of the femoral head and secondary osteoarthritis, a valgus intertrochanteric osteotomy may allow better congruency but the acetabular cover may become insufficient because of subluxation of the femoral head. In patients with a spherical femoral head and acetabular dysplasia, cover can still remain insufficient after varus displacement osteotomy. We present the long-term results of intertrochanteric osteotomy combined with an acetabular shelfplasty in both these circumstances.

Sixteen hips (15 patients) with a deformed femoral head, and ten (seven patients) with a spherical femoral head, underwent an intertrochanteric osteotomy and acetabular shelfplasty. The mean age at the time of surgery was 30 and 37 years and the mean final follow-up was 15 and 19 years, respectively. Six patients in the deformed group, but only one in the spherical group, had required a THR by the time of their final follow-up. In both groups, those who had not undergone a THR had a good result.

Acetabular shelfplasty is an excellent addition to an intertrochanteric osteotomy and gives full cover of the femoral head in patients with a deformity of the head and secondary osteoarthritis.

Injection or aspiration of the ankle may be performed through either an anteromedial or an anterolateral approach for diagnostic or therapeutic reasons. We evaluated the success of an intra-articular puncture in relation to its site in 76 ankles from 38 cadavers. Two orthopaedic surgical trainees each injected methylene blue dye into 18 of 38 ankles through an anterolateral approach and into 20 of 38 through an anteromedial. An arthrotomy was then performed to confirm the placement of the dye within the joint.

Of the anteromedial injections 31 of 40 (77.5%, 95% confidence interval (CI) 64.6 to 90.4) were successful as were 31 of 36 (86.1%, 95% CI 74.8 to 97.4) anterolateral injections. In total 62 of 76 (81.6%, 95% CI 72.9 to 90.3) of the injections were intra-articular with a trend towards greater accuracy with the anterolateral approach, but this difference was not statistically significant (p = 0.25). In the case of trainee A, 16 of 20 anteromedial injections and 14 of 18 anterolateral punctures were intra-articular. Trainee B made successful intra-articular punctures in 15 of 20 anteromedial and 17 of 18 anterolateral approaches. There was no significant difference between them (p = 0.5 and p = 0.16 for the anteromedial and anterolateral approaches, respectively). These results were similar to those of other reported studies. Unintended peri-articular injection can cause complications and an unsuccessful aspiration can delay diagnosis. Placement of the needle may be aided by the use of ultrasonographic scanning or fluoroscopy which may be required in certain instances.

There are few reports of the surgical treatment for late stage Freiburg’s disease with flattening of the metatarsal head and osteoarthritis. We describe the results of the surgical treatment of ten consecutive patients with advanced stage Freiburg’s disease (Smillie’s stage V), using a technique that has not been published previously.

Traumatic posterior dislocation of the hip associated with a fracture of the posterior acetabular wall and of the neck of the femur is a rare injury. A 29-year-old man presented at a level 1 trauma centre with a locked posterior dislocation of the right hip, with fractures of the femoral neck and the posterior wall of the acetabulum after a bicycle accident. An attempted closed reduction had failed. This case report describes in detail the surgical management and the clinical and radiological outcome. Open reduction and fixation with preservation of the intact retinaculum was undertaken within five hours of injury with surgical dislocation of the hip and a trochanteric osteotomy. Two years after operation the function of the injured hip was good. Plain radiographs and MR scans showed early signs of osteoarthritis with some loss of joint space but no evidence of avascular necrosis. The patient had begun skiing and hiking again.

The combination of fractures of the neck of the femur and of the posterior wall of the acetabulum hampers closed reduction of a posterior dislocation of the hip. Surgical dislocation of the hip with trochanteric flip osteotomy allows controlled open reduction of the fractures, with inspection of the hip joint and preservation of the vascular supply.

In Neer type II (Robinson type 3B) fractures of the distal clavicle the medial fragment is detached from the coracoclavicular ligaments and displaced upwards, whereas the lateral fragment, which is usually small, maintains its position. Several fixation techniques have been suggested to treat this fracture. The aim of this study was to assess the outcome of patients with type II distal clavicle fractures treated with coracoclavicular suture fixation using three loops of Ethibond. This prospective study included 14 patients with Neer type II fractures treated with open reduction and coracoclavicular fixation. Ethibond sutures were passed under the coracoid and around the clavicle (UCAC loop) without making any drill holes in the proximal or distal fragments. There were 11 men and three women with a mean age of 34.57 years (29 to 41). Patients were followed for a mean of 24.64 months (14 to 31) and evaluated radiologically and clinically using the Constant score. Fracture union was obtained in 13 patients at a mean of 18.23 weeks (13 to 23) and the mean Constant score was 96.07 (91 to 100). One patient developed an asymptomatic fibrous nonunion at one year. This study suggests that open reduction and internal fixation of unstable distal clavicle fractures using UCAC loops can provide rigid fixation and lead to bony union. This technique avoids using metal hardware, preserves the acromioclavicular joint and provides adequate stability with excellent results.

Cite this article: Bone Joint J 2013;95-B:983–7.

We report the effects of local administration of osteogenic protein-1 on the biomechanical properties of the overstretched anterior cruciate ligament in an animal model. An injury in the anterior cruciate ligament was created in 45 rabbits. They were divided into three equal groups. In group 1, no treatment was applied, in group II, phosphate-buffered saline was applied around the injured ligament, and in group III, 12.5 μg of osteogenic protein-1 mixed with phosphate-buffered saline was applied around the injured ligament. A control group of 15 rabbits was assembled from randomly-selected injured knees from among the first three groups. Each rabbit was killed at 12 weeks.

The maximum load and stiffness of the anterior cruciate ligament was found to be significantly greater in group III than either group 1 (p = 0.002, p = 0.014) or group II (p = 0.032, p = 0.025). The tensile strength and the tangent modulus of fascicles from the ligament were also significantly greater in group III than either group I (p = 0.002, p = 0.0174) or II (p = 0.005, p = 0.022).

The application of osteogenic protein-1 enhanced the healing in the injured anterior cruciate ligament, but compared with the control group the treated ligament remained lengthened. The administration of osteogenic protein-1 may have a therapeutic role in treating the overstretched anterior cruciate ligament.

We report the results at a mean of 24.3 years (20 to 32) of 61 previously reported consecutive total hip replacements carried out on 44 patients with severe congenital hip disease, performed with reconstruction of the acetabulum with an impaction grafting technique known as cotyloplasty. The mean age of the patients at operation was 46.7 years (23 to 68) and all were women. The patients were followed post-operatively for a mean of 24.3 years (20 to 32), using the Merle d’Aubigné and Postel scoring system as modified by Charnley, and with serial radiographs. At the time of the latest follow-up, 28 acetabular components had been revised because of aseptic loosening at a mean of 15.9 years (6 to 26), and one at 40 days after surgery because of repeated dislocations. The overall survival rate for aseptic failure of the acetabular component at ten years was 93.1% (95% confidence interval (CI) 86.5 to 96.7) when 53 hips were at risk, and at 23 years was 56.1% (95% CI 49.4 to 62.8), when 22 hips remained at risk. These long-term results are considered satisfactory for the reconstruction of an acetabulum presenting with inadequate bone stock and circumferential segmental defects.

Cite this article: Bone Joint J 2013;95-B:887–92.

Coronal plane fractures of the posterior femoral condyle, also known as Hoffa fractures, are rare. Lateral fractures are three times more common than medial fractures, although the reason for this is not clear. The exact mechanism of injury is likely to be a vertical shear force on the posterior femoral condyle with varying degrees of knee flexion. These fractures are commonly associated with high-energy trauma and are a diagnostic and surgical challenge. Hoffa fractures are often associated with inter- or supracondylar distal femoral fractures and CT scans are useful in delineating the coronal shear component, which can easily be missed. There are few recommendations in the literature regarding the surgical approach and methods of fixation that may be used for this injury. Non-operative treatment has been associated with poor outcomes. The goals of treatment are anatomical reduction of the articular surface with rigid, stable fixation to allow early mobilisation in order to restore function. A surgical approach that allows access to the posterior aspect of the femoral condyle is described and the use of postero-anterior lag screws with or without an additional buttress plate for fixation of these difficult fractures.

Cite this article: Bone Joint J 2013;95-B:1165–71.

Twins are often considered to be at an increased risk of developmental dysplasia of the hip (DDH); we therefore investigated whether multiple births have a higher incidence of DDH, and if selective ultrasound scanning should be considered for these infants.

We reviewed our records of all live births between 1 January 2004 and 31 December 2008 and included 25 246 single and 990 multiple births.

Multiple births did not have a significantly higher incidence of DDH compared with single births (0.0030 vs 0.0023, p = 0.8939). Of the 990 multiple births, 267 had neonatal ultrasound scans and one case of DDH was diagnosed and treated successfully with a Pavlik harness. There were two late-presenting cases at eight and 14 months of age, neither of whom had risk factors for DDH and consequently had not had a neonatal scan. Whereas selective ultrasound scanning of multiple births would have led to earlier detection and treatment of the late-presenting cases, they did not have a significantly higher incidence of DDH compared with single births.

We conclude that being a twin or triplet in itself is not a risk factor for DDH and that selective ultrasound scanning is not indicated for this population.

Cite this article: Bone Joint J 2013;95-B:132–4.

We have developed an animal model to examine the formation of heterotopic ossification using standardised muscular damage and implantation of a beta-tricalcium phosphate block into a hip capsulotomy wound in Wistar rats. The aim was to investigate how cells originating from drilled femoral canals and damaged muscles influence the formation of heterotopic bone. The femoral canal was either drilled or left untouched and a tricalcium phosphate block, immersed either in saline or a rhBMP-2 solution, was implanted. These implants were removed at three and 21 days after the operation and examined histologically, histomorphometrically and immunohistochemically.

Bone formation was seen in all implants in rhBMP-2-immersed, whereas in those immersed in saline the process was minimal, irrespective of drilling of the femoral canals. Bone mineralisation was somewhat greater in the absence of drilling with a mean mineralised volume to mean total volume of 18.2% (sd 4.5) versus 12.7% (sd 2.9, p < 0.019), respectively.

Our findings suggest that osteoinductive signalling is an early event in the formation of ectopic bone. If applicable to man the results indicate that careful tissue handling is more important than the prevention of the dissemination of bone cells in order to avoid heterotopic ossification.

There are several methods for evaluating stability of the joint during total knee replacement (TKR). Activities of daily living demand mechanical loading to the knee joint, not only in full extension, but also in mid-flexion. The purpose of this study was to compare the varus-valgus stability throughout flexion in knees treated with either cruciate-retaining or posterior-stabilised TKR, using an intra-operative navigation technique. A total of 34 knees underwent TKR with computer navigation, during which the investigator applied a maximum varus-valgus stress to the knee while steadily moving the leg from full extension to flexion both before and after prosthetic implantation. The femorotibial angle was measured simultaneously by the navigation system at every 10° throughout the range of movement. It was found that posterior-stabilised knees had more varus-valgus laxity than cruciate-retaining knees at all angles examined, and the differences were statistically significant at 10° (p = 0.0093), 20° (p = 0.0098) and 30° of flexion (p = 0.0252).

Cite this article: Bone Joint J 2013;95-B:493–7.

The use of joint-preserving surgery of the hip has been largely abandoned since the introduction of total hip replacement. However, with the modification of such techniques as pelvic osteotomy, and the introduction of intracapsular procedures such as surgical hip dislocation and arthroscopy, previously unexpected options for the surgical treatment of sequelae of childhood conditions, including developmental dysplasia of the hip, slipped upper femoral epiphysis and Perthes’ disease, have become available. Moreover, femoroacetabular impingement has been identified as a significant aetiological factor in the development of osteoarthritis in many hips previously considered to suffer from primary osteoarthritis.

As mechanical causes of degenerative joint disease are now recognised earlier in the disease process, these techniques may be used to decelerate or even prevent progression to osteoarthritis. We review the recent development of these concepts and the associated surgical techniques.

Cite this article: Bone Joint J 2014;96-B:5–18.

Total hip replacement for high dislocation of the hip joint remains technically difficult in terms of preparation of the true acetabulum and restoration of leg length. We describe our experience of cementless total hip replacement combined with a subtrochanteric femoral shortening osteotomy in 20 hips with Crowe grade IV dislocation with a mean follow-up of 8.1 years (4 to 11.5). There was one man and 17 women with a mean age of 55 years (44 to 69) at the time of the operation.

After placment of the acetabular component at the site of the natural acetabulum, a cementless porous-coated cylindrical femoral component was implanted following a subtrochanteric femoral shortening osteotomy.

The mean Japanese Orthopedic Association hip score improved from a mean of 38 (22 to 62) to a mean of 83 points (55 to 98) at the final follow-up. The mean lengthening of the leg was 14.8 mm (−9 to 34) in patients with iliofemoral osteoarthritis and 35.3 mm (15 to 51) in patients with no arthritic changes. No nerve palsy was observed.

Total hip replacement combined with subtrochanteric shortening femoral osteotomy in this situation is beneficial in avoiding nerve injury and still permits valuable improvement in inequality of leg length.