We used dual-energy X-ray absorptiometry (DEXA) to measure the bone mineral content (BMC) of both tibiae in 13 patients who had been treated for a tibial fracture by rigid plate fixation. Within two weeks of plate removal the BMC was significantly greater in the bone that had been under the plate than at the same site in the control tibia. An unplated area of bone near the ankle showed a significant decrease in BMC at the time of plate removal with subsequent return to the level of the control tibia during the ensuing 18 months. We conclude that osteoinductive influences outweigh the potential causes of osteopenia, such as stress shielding and disuse, and that, contrary to expectation, demineralisation is not a factor in the diminished strength of the tibia after plating for fracture

Aims

To compare complication-related reoperation rates following primary arthroplasty for proximal humerus fractures (PHFs) versus secondary arthroplasty for failed open reduction and internal fixation (ORIF).

We have compared the survival of 67 revision arthroplasties of the knee undertaken for aseptic loosening with and without the retention of a secure, cemented femoral component. All the patients had undergone a single primary procedure at a mean of nine years previously. In group I (25 knees) the original femoral component was secure and was retained. There were no abrasions or osteolysis. The knees were stable, normally aligned, with minimal bone loss. In group II 42 knees did not fulfil these criteria and underwent revision of both components. The mean follow-up was four years. Re-revision for loosening was required in seven knees (28%) in group I and three (7%) in group II (p < 0.01). The remaining knees function well with Knee Society scores averaging 84/69 and no radiological evidence of osteolysis. When revising cemented implants, retention of a secure femoral component cannot be recommended even when conditions appear to be suitable

Exchange nailing for failure of union after primary intramedullary nailing of the tibia is widely used but the indications and effectiveness have not been reported in detail. We have reviewed 33 cases of uninfected nonunion of the tibia treated by exchange nailing. This technique was successful without open bone grafting in all closed fractures and in open fractures of Gustilo types I, II and IIIa. The requirement for open bone grafting was reduced in type-IIIb fractures, but exchange nailing failed in type-IIIb fractures with significant bone loss. For these we recommend early open bone grafting. The most common complication was wound infection, seen more often than after primary nailing. We discuss our protocol for the use and timing of exchange nailing of all grades and types of tibial fracture

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

One hundred and sixteen patients with 129 ununited fractures were treated either by rigid internal fixation and bone grafting or, in 14 tibial non-unions, by posterolateral bone grafting. In 37 actively infected cases this was combined with sequestrectomy and appropriate antibiotics. The final success rate was 98.4%. Technical errors or inadequate immobilisation after operation in patients with severe osteoporosis led to some early failures. No patient had a discharge or evidence of osteomyelitis after removal of metal. Rigid internal fixation with or without bone grafting is the treatment of choice for established non-union with bone loss when true synovial pseudarthrosis is present, when malalignment or shortening needs correction, and when prolonged immobilisation is either difficult or would lead to unacceptable stiffness in adjacent joints. Active osteomyelitis is not a contra-indication to internal fixation

The occurrence of a radiolucent line at the interface of bone and cement in total joint prostheses is a frequently observed, although little understood, phenomenon. Because of an operative technique utilised in instances of bone loss, we have, within a single implant mass used in each of a series of 18 total knee replacements, been able to observe two separate interfaces, one between bone and cement and the other between bone and cobalt chrome. The average period of observation was 32 months. All of the knees except one demonstrated a lucency at the bone-cement interface; only one of the knees had a similar lucency at the bone-CoCr interface. One of the knees was studied histologically. In the light of the universal observation of macrophages at bone-cement interfaces and the recent finding that osteoclasts are derived from macrophages, these observations are significant in relation to the aetiology of bone-cement lucencies

The relationship between the bone mineral density (BMD) and Charcot arthropathy is unclear. Prospectively, 55 consecutive diabetic patients presenting with a Charcot arthropathy of the foot or ankle were classified as having a fracture, dislocation, or a combination fracture-dislocation pattern of initial destruction. In these groups we used dual-energy x-ray absorptiometry to compare the peripheral bone of the affected and unaffected limbs. The clinical data relating to diabetes and related major comorbidities and the site of the arthropathy (ankle, hindfoot, midfoot, forefoot) were also compared. There were 23 patients with a fracture pattern, 23 with a dislocation pattern, and nine with a combination. The age-adjusted odds ratio for developing a Charcot joint with a fracture pattern as opposed to a dislocation pattern in patients with osteopenia was 9.5 (95% confidence interval 2.4 to 37.4; p = 0.0014). Groups also differed as to the site of the arthropathy. Fracture patterns predominated at the ankle and forefoot whereas dislocations did so in the midfoot. Diabetic Charcot arthropathy of the foot and ankle differs according to the pattern of the initial destruction. The fracture pattern is associated with peripheral deficiency of BMD. The dislocation pattern is associated with a normal BMD

The radiographic and histological features of radiolucent areas at the cement-bone interface were correlated in 15 specimens retrieved at post-mortem from patients who had undergone cemented total hip arthroplasty, two weeks to 15 years prior to death. All but one of the components were securely fixed, as demonstrated by direct measurements of micromotion. Extensive radiolucencies were present in all but one case. In 11 of the 14 specimens with radiolucencies, histological examination showed that the radiolucent areas represented regions of osteoporosis and bone remodelling. The remodelling changes were characterised by osteoporosis, cancellisation and thinning of the endosteal cortex, and osteopenia of the trabecular bone. In two specimens the appearance of radiolucency was found to be due to fibrous tissue at the cement-bone interface and in one specimen there was a mixed picture of osteolysis and fibrosis. The study demonstrates that radiolucent lines can occur with well-fixed components and that they may commonly represent osteoporosis rather than the presence of a fibrous membrane at the cement-bone interface

Seventy-nine open tibial fractures were treated with unilateral uniplanar tubular external fixators. Excellent stability allowed early weight-bearing. All comminuted fractures, with or without bone loss, and some transverse or short oblique fractures with intermediate fragments were treated by early bone grafting through a posterolateral approach. The external fixator was dynamised as soon as periosteal callus was seen on the radiograph. Bone healing times ranged from 11 to 40 weeks (mean 20). Significant ankle stiffness occurred in 10.9% and leg shortening in 2.8%. Pin track infection was seen in 45.2% but was easily controlled with standard management. The external fixation frame allowed excellent functional freedom for Oriental patients to sit cross-legged and squat. Combined with early bone grafting, external fixation is an excellent method for the management of open tibial fractures

Visualisation of periacetabular osteolysis by standard anteroposterior (AP) radiographs underestimates the extent of bone loss around a metal-backed acetabular component. We have assessed the effectiveness of standard radiological views in depicting periacetabular osteolysis, and recommend additional projections which make these lesions more visible. This was accomplished using a computerised simulation of radiological views and a radiological analysis of simulated defects placed at regular intervals around the perimeter of a cadaver acetabulum. The AP view alone showed only 38% of the defects over all of the surface of the cup and failed to depict a 3 mm lesion over 83% of the cup. When combined with the AP view, additional 45° obturator-oblique and iliac-oblique projections increased the depiction, showing 81% of the defects. The addition of the 60° obturator-oblique view further improved the visualisation of posterior defects, increasing the rate of detection to 94%. Based on this analysis, we recommend using at least three radiographic views when assessing the presence and extent of acetabular osteolysis

Loosening is a serious problem in total arthroplasty and early detection of bone loss in the vicinity of an implant would help in its investigation. We present a method for the objective evaluation of bone adjacent to metallic implants in which a modified technique of quantitative computed tomography (QCT) is used to reconstruct cross-sectional images with few artefacts. We have used this technique in 19 patients with knee arthroplasties to monitor the changes in bone density around the tibial stem of the prosthesis. In the first weeks after operation all patients showed a decrease in bone density ranging from 0.4% to 3.6% per month. One year after arthroplasty bone density had stabilised and only minor changes were observed. Our work indicates that modified QCT is a sensitive method for the long-term monitoring of the anchorage of implants and allows the early detection of osteolytic changes

A new dynamic classification of Paget's disease is proposed, incorporating both the radiographic phases of bone remodelling and the scintigraphic findings. Osteolytic, mixed and osteoblastic phases are associated with increased scintigraphic activity, while the osteosclerotic phase of remodelling is associated with normal or diminished activity and an osteoblastic radiographic appearance. Abnormal modelling of bone leading to deformity is produced by accelerated apposition or absorption at the periosteal and endosteal envelopes of the bone. In 112 patients with symptoms from Paget's disease, 527 lesions were classified. The most frequent remodelling phase was the mixed one and the most common modelling state was bone expansion with endosteal and periosteal apposition. Of 88 patients treated medically, 12 had lesions which progressed to increased bone formation without a change in modelling, and the active lesions in seven patients became inactive. Prolonged treatment with disodium etidronate led to progressive osteopenia in 11 patients

Extensive osteolysis adjacent to implants is often associated with wear particles of prosthetic material. We have investigated if RANKL, also known as osteoprotegerin ligand, osteoclast differentiation factor or TRANCE, and its natural inhibitor, osteoprotegerin (OPG), may be important in controlling this bone loss. Cells isolated from periprosthetic tissues containing wear particles expressed mRNA encoding for the pro-osteoclastogenic molecules, RANKL, its receptor RANK, monocyte colony-stimulating factor (M-CSF), interleukin (IL)-1β, tumour necrosis factor (TNF)α, IL-6, and soluble IL-6 receptor, as well as OPG. Osteoclasts formed from cells isolated from periprosthetic tissues in the presence and absence of human osteoblastic cells. When osteoclasts formed in the absence of osteoblastic cells, markedly higher levels of RANKL mRNA relative to OPG mRNA were expressed. Particles of prosthetic materials also stimulated human monocytes to express osteoclastogenic molecules in vitro. Our results suggest that ingestion of prosthetic wear particles by macrophages results in expression of osteoclast-differentiating molecules and the stimulation of macrophage differentiation into osteoclasts

Forty failed hinged arthroplasties of the knee were revised by the insertion of another hinged implant. In 14 cases the prosthesis used at the revision operation was similar to the primary implant; in 26, a hinge with an elongated femoral stem was used, usually replacing part of the femoral shaft. In seven of these knees an elongated tibial stem was also required, though the tibial shaft was replaced in only two of them. There were many complications. Fracture of the femur at the tip of the femoral stem was the most frequent. Sixteen first revisions failed and were revised a second time; 12 required replacement of the distal femoral shaft and three required replacement of the proximal tibia. The incidence of complications in knees requiring a second revision was even higher. Four required a third revision after an average interval of three years. Failure of a hinged prosthesis results in bone loss mainly in the femur. Revision of a failed hinged prosthesis with another of the same design is unlikely to be successful and may cause fracture of the femur

Bone loss around replacement prostheses may be related to the activation of mononuclear phagocytes (MNP) by prosthetic wear particles. We investigated how osteoblast-like cells were regulated by human MNP stimulated by particles of prosthetic material. Particles of titanium-6-aluminium-4-vanadium (TiAlV) stimulated MNP to release interleukin (IL)-1β, tumour necrosis factor (TNF)α, IL-6 and prostaglandin E. 2. (PGE. 2. ). All these mediators are implicated in regulating bone metabolism. Particle-activated MNP inhibited bone cell proliferation and stimulated release of IL-6 and PGE. 2. The number of cells expressing alkaline phosphatase, a marker associated with mature osteo-blastic cells, was reduced. Experiments with blocking antibodies showed that TNFα was responsible for the reduction in proliferation and the numbers of cells expressing alkaline phosphatase. By contrast, IL-1β stimulated cell proliferation and differentiation. Both IL-1β and TNFα stimulated IL-6 and PGE. 2. release from the osteoblast-like cells. Our results suggest that particle-activated mono-nuclear phagocytes can induce a change in the balance between bone formation and resorption by a number of mechanisms

High-pressure lavage produces greater visible damage to bone at a macroscopic and microscopic level when compared with low-pressure lavage and can result in delay in the healing of fractures. Osteoblasts and adipocytes are derived from mesenchymal stem cells. Conditions which lead to bone loss often involve a switch from the osteoblast to adipocyte lineage. We have therefore examined the effect of high- and low-pressure irrigation on the differentiation of adipocytes. Calvaria-derived bone cells were exposed to either low-pressure or high-pressure irrigation with normal saline. After 14 days the cells were fixed and the osteoblasts and adipocytes quantified using Oil Red O to stain cytoplasmic lipid droplets (triglycerides) in the cells. Osteoblasts were quantified using a commercially available alkaline-phosphatase staining assay. A standard quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed. Messenger RNA levels for osteocalcin, a marker of osteoblasts, and PPARγ2, a marker of adipocytes, were measured. High-pressure lavage resulted in an increase in adipogenesis of 50% when compared with low-pressure lavage. Our findings suggest that high-pressure lavage may promote differentiation of mesenchymal stem cells towards the adipoctye lineage. This may have clinical significance in the development of delayed and nonunion after treatment of fractures of long bones

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.

Total hip replacement using porous-coated cobalt-chrome femoral implants designed for biological fixation has been evaluated in 307 patients after two years and in 89 patients after five years. Histological study of 11 retrieved specimens showed bone ingrowth in nine and fibrous tissue fixation in two. Fixation by bone ingrowth occurred in 93% of the cases in which a press fit of the stem at the isthmus was achieved, but in only 69% of those without a press fit. The clinical results at two years were excellent. The incidence of pain and limp was much lower when there was either a press fit of the stem or radiographic evidence of bone ingrowth. Factors such as age, sex, and the disease process did not influence the clinical results. Most cases showed only slight resorptive remodelling of the upper femur, but in a few cases with a larger, more rigid stem, more extensive bone loss occurred. The results after five years showed no deterioration with time. Fixation by the ingrowth of bone or of fibrous tissue both appeared to be stable, but bone ingrowth gave better clinical results