Objectives

Patient-specific (PS) implantation surgical technology has been introduced in recent years and a gradual increase in the associated number of surgical cases has been observed. PS technology uses a patient’s own geometry in designing a medical device to provide minimal bone resection with improvement in the prosthetic bone coverage. However, whether PS unicompartmental knee arthroplasty (UKA) provides a better biomechanical effect than standard off-the-shelf prostheses for UKA has not yet been determined, and still remains controversial in both biomechanical and clinical fields. Therefore, the aim of this study was to compare the biomechanical effect between PS and standard off-the-shelf prostheses for UKA.

Plain radiographs show only two dimensions of a three-dimensional object. On anteroposterior and lateral radiographs an implant may appear to be safely within the head of the femur although surface penetration has occurred. We have attempted to identify this complication in the treatment of fractures of the femoral neck and have analysed the position of a screw or pin in the femoral head and neck on the basis of orthogonal frontal and lateral radiographs. A retrospective analysis of 60 cases of osteosynthesis of fractures of the femoral neck confirmed the risk of non-recognition of articular penetration or breaking of the cortex of the neck during surgery. Unrecognised screw penetration of the hip was observed in 8% and of the posterior part of the neck in 10%. The risk differs according to the type of fracture: it is greater in the coxa valga produced by Garden-I fractures of the femoral neck

1. Discs of bone from two fixed sites on the front of the femur were taken from ninety-one necropsy subjects and the density, width and histological appearance of the cortical bone were examined. 2. Cortical thickness, and the density of the femoralcortex, decreased with increasingage of bone. 3. There was an increase in the rate of resorption of the bone cortex from both sexes after the fifth decade. 4. The difference between the density of the metaphysial cortex and that from the diaphysis increased for both sexes after the age of fifty, because of the greater metaphysial resorption. 5. There was no change in the degree of mineralisation of the cortical bone with age. The decrease in density with age is, therefore, accounted for by resorption

1. A pathological study has been made of eight femurs containing acrylic Judet type prostheses, in patients who had died two to thirteen weeks after arthroplasty. 2. Haemorrhage occurs into the tunnel and into a limited zone of the spongy bone around the tunnel. Organisation of the blood clot is evident at two weeks and new bone formation appears shortly afterwards. At eight weeks the tunnel is lined by a fibrous membrane. Further fibrosis and new bone growth tend to establish a new surface, healing the wound in the bone and sequestrating the foreign body. 3. There is no evidence that the intact methyl-methacrylate appliance had exerted any toxic action on the tissues

We enrolled 98 patients (107 hips) with a mean age of 47 years (SD 8.6) into a prospective study of the Madreporic Lord THR; 34 hips had primary and 73 secondary osteoarthritis. After ten years, the survival rate using revision as the endpoint for failure was 70% (±9) for the cup and 98% (±0.3) for the stem. The combined clinical and radiological survival rates were 46% (±11) and 81% (±10), respectively. Osteoporosis due to stress-shielding was observed in the proximal femur. Hips with radiologically dense bone postoperatively showed the most pronounced bone loss. We recommend continued radiological follow-up of patients with this type of implant to allow revision to be performed before there is severe bony destruction of the pelvis

We prospectively evaluated the percutaneous injection of autogenous bone marrow for the treatment of active simple bone cysts in ten consecutive children with cysts in the proximal humerus, proximal femur or tibia. The treatment included percutaneous biopsy, aspiration of fluid and the injection of autogenous bone marrow aspirated from the iliac crest. All the patients became painfree after a mean of two weeks and resumed full activities within six weeks. All ten cysts consolidated radiologically and showed remarkable remodelling within four months. Review at 12 to 48 months showed satisfactory healing without complications. Percutaneous injection of autologous bone marrow appears to be an effective treatment for active simple bone cysts

We studied the reliability of the Singh classification of trabecular bone structure in the proximal femur as a measure of osteoporosis, using kappa statistics. Radiographs of fractures of the femoral neck or trochanteric region in 80 consecutive patients were assessed by six observers. The interobserver variation was large; only three of 72 radiographs were given the same classification by all six observers and the kappa values ranged from 0.15 to 0.54. The intraobserver variation showed substantial strength of agreement; kappa values ranged from 0.63 to 0.88. In 77 patients dual-energy X-ray absorptiometry was used to measure bone mineral density. The results were compared with those of the Singh classification: we found no correlation

A total of 30 patients who underwent endoscopic reconstruction of the anterior cruciate ligament using quadrupled hamstring tendons, through a single drill hole in the femur, had MRI 24 to 28 months after operation. In 18 patients the scans revealed that both the anterior and posterior portions of the graft ran in parallel from the inside of the femoral to the tibial tunnel. In 12, the posterior bundle had moved anteriorly and the anterior bundle could not be identified at the anterodistal border of the femoral tunnel. The mean difference in the anterior laxity, when compared with the contralateral knee, was 2.0 ± 1.7 mm and 4.3 ± 2.8 mm for the two types, respectively. Damage to the anterior bundle may occur when using the endoscopic technique because of biomechanical disadvantages, including concentration of loading and repetitive bending stress in the anterior bundle at the opening of the femoral tunnel

There are several techniques for the accurate measurement of the migration of components after arthroplasty some of which require the operative placement of tantalum balls. We have reviewed the position and migration of these markers in 64 patients after total hip arthroplasty. In 40% of cases, one or more balls was seen to be outside the proximal femur on the postoperative radiograph, although all were considered to be within the bone at operation. In two hips, one ball appeared to have migrated towards the joint, although none was seen within the joint. Misplacement was not related to the experience of the surgeon or the operative approach. Migration analysis which necessitates the insertion of tantalum balls requires careful technique to avoid a potential source of third-body wear. It should probably be used only for research in small series of patients

A consecutive series is reported of 17 patients who underwent early surgical treatment for acetabular or unstable pelvic fractures associated with ipsilateral fractures of the femur. Treatment included external and internal fixation, and required careful consideration of the surgical approach and the positioning of the patient. The multiple injuries sustained by these patients required simultaneous procedures by several surgical teams. All the femoral fractures were internally fixed at the initial operation and eight patients had primary definitive treatment of all their other fractures as well. In nine patients the definitive treatment of their other fractures was delayed for an average of 11 days. There were no deaths, and no serious infections. The long-term morbidity resulted from the associated injuries and not from the pelvic or femoral fractures

We have reviewed the literature on the anatomy of the posteromedial peripheral ligamentous structures of the knee and found differing descriptions. Our aim was to clarify the differing descriptions with a simplified interpretation of the anatomy and its contribution to the stability of the knee. We dissected 20 fresh-frozen cadaver knees and the anatomy was recorded using video and still digital photography. The anatomy was described by dividing the medial collateral ligament (MCL) complex into thirds, from anterior to posterior and into superficial and deep layers. The main passive restraining structures of the posteromedial aspect of the knee were found to be superficial MCL (parallel, longitudinal fibres), the deep MCL and the posteromedial capsule (PMC). In the posterior third, the superficial and deep layers blend. Although there are oblique fibres (capsular condensations) running posterodistally from femur to tibia, no discrete ligament was seen. In extension, the PMC appears to be an important functional unit in restraining tibial internal rotation and valgus. Our aim was to clarify and possibly simplify the anatomy of the posteromedial structures. The information would serve as the basis for future biomechanical studies to investigate the contribution of the posteromedial structures to joint stability

Total hip replacement has been very successful in patients with painful, stiff hips associated with protrusio acetabuli, but the heat of polymerisation of methylmethacrylate cement may cause necrosis of the thin medial wall with consequent danger of migration of the cup. Since 1968 at Wrightington, thin slices of the head of the femur have been used as bone grafts to reinforce the acetabulum. We have reviewed 61 hips in 51 patients at an average of 4 years 3 months after operation. Grading for severity is discussed and the degree of physiological remodelling of the medial wall of the acetabulum after grafting assessed. There was an average of about 4 mm of remodelling, but this varied considerably; most took place within the first year. In no case was there relapse of the protrusio

Hemiarthroplasty of the hip and some other joints has been used for many years with satisfactory results, but the fate of articular cartilage when weight-bearing against metal has not been reported. Replacement of the head of the femur was carried out in one hip of each of 26 dogs, and the changes in acetabular cartilage studied at intervals of up to 24 weeks. There was early loss of proteoglycan, followed by surface damage to the cartilage, progressive degenerative changes, and growth of pannus from the articular margins. At 24 weeks after operation there was little remaining articular cartilage, while intense subchondral activity suggested that the bony skeleton was being remodelled to conform to the shape of the prosthesis. This study is not intended to suggest that hemiarthroplasty does not help patients

This paper describes a new technique for greater trochanteric hip arthroplasty in which the femur is divided at the subtrochanteric level and the upper fragment rotated through 180 degrees to place the greater trochanter deeply in the acetabulum; with the lower limb in the weight-bearing position the fragments are then fixed with a short intramedullary nail. This operation was carried out in a boy aged 4 years 6 months in whom the femoral head and neck had been destroyed by septic arthritis. Ten years later leg-lengthening was performed. When reviewed at the age of 20, he had a stable hip, a satisfactory range of painless movement, and shortening of only 2.5 cm; he could walk and run for long distances with only a slight abductor lunch

The Brittain V-arthrodesis is a satisfactory procedure for osteoarthritis of the hip. It is particularly suitable for elderly patients when the range of hip flexion is less than 60 degrees. If the four deaths are excluded, two-thirds of the patients secured a sound bony fusion. This occurs slowly. All but one of the patients who survived for three years or more after operation had a sound bony fusion. It is evident that the operation, given time, yields a high rate of sound bony fusion in the hip. It seems likely that use of the McLaughlin nail plate would prevent the one serious complication, namely fracture of the shaft of the femur through or immediately below the drill hole made for the fibular graft

1. A collected series of forty-seven traumatic dislocations of the hip in children is reported and reviewed in detail. 2. All were simple hip dislocations, and no child was included in whom there was any other injury to the affected joint. 3. All were posterior dislocations. 4. No anatomical predisposition was observed. 5. Significant complications occurred in fourteen children: avascular necrosis of the head of the femur in four, degenerative joint changes in three, premature epiphysial fusion in one and overgrowth of the femoral head in six. Study of the children with these complications revealed no common cause except the dislocation itself. 6. The injury responsible was often trivial. 7. The results suggest that it is harmless to bear weight four weeks after reduction

1. The structure and blood supply of the femoral head and neck, the mechanics of weight bearing, and the known effects of an inert foreign body are considered in relation to arthroplasty. 2. Some artificial hips are reviewed from the biomechanical standpoint. 3. From the information now available it is inferred that mechanical soundness and clinical success are not only co-related but interdependent; and that the mechanical problem of design offers most scope for further development at the present stage of our knowledge. 4. To this end six propositions are submitted. 5. A theoretical replacement arthroplasty, confined to the head and neck, in which breakdown of the component forces suggests that reciprocal use of both tensional and compressive loads might occur as in the natural femur, is described

Based on the constancy with which the limbus is inverted into the joint in a typical congenital dislocation of the hip, a hypothesis is presented which suggests that the sequence of events leading to established dislocation is: 1) lateral rotation aided and abetted by anteversion; 2) extension of the hips causing subluxation; 3) dislocation and inversion of the limbus; 4) secondary changes in the upper end of the femur, pelvis and acetabulum which will also develop if the deformity does not progress beyond a subluxation. A pen picture is drawn showing how anteversion is either moulded away during growth to produce a normal hip, or persists with or without dislocation. The fate of the persistently inverted limbus is discussed and a line of treatment based on these findings is briefly considered

A total of 63 women who had an operation for a fracture of the hip was randomly allocated to one year of treatment either with anabolic steroids, vitamin D and calcium (anabolic group) or with calcium only (control group). The thigh muscle volume was measured by quantitative CT. The bone mineral density of the hip, femur and tibia was assessed by quantitative CT and dual-energy x-ray absorptiometry and of the heel by quantitative ultrasound. Quantitative CT showed that the anabolic group did not lose muscle volume during the first 12 months whereas the control group did (p< 0.01). There was less bone loss in the proximal tibia in the anabolic group than in the control group. The speed of gait and the Harris hip score were significantly better in the anabolic group after six and 12 months. Anabolic steroids, even in this moderate dose, given in combination with vitamin D and calcium had a beneficial effect on muscle volume, bone mineral density and clinical function in this group of elderly women

We report retrospective and prospective studies to identify the causes of fracture of the femoral neck associated with femoral shaft nailing on the same side. Of a total of 14 neck fractures in a series of 152 shaft nailings, eight were not visible on the initial pelvic radiographs. We used CT scans before and after operation, and fluoroscopy during the procedure in our prospective series, and reviewed abdominal CT scans retrospectively with the window set to bone level. Six of the eight undisplaced fractures were shown to have been present before operation, but two were iatrogenic. We recommend the preoperative use of CT scans of the femoral neck in high-risk patients such as those with associated fractures of the acetabulum, the distal femur or the patella. Early diagnosis will allow better general management and early fixation of the neck fracture