Aims. The aim of this study was to determine the rate of indocyanine green (ICG) staining of bone and soft-tissue tumours, as well as the stability and accuracy of ICG fluorescence imaging in detecting tumour residuals during surgery for bone and soft-tissue tumours. Methods. ICG fluorescence imaging was performed during surgery in 34 patients with bone and soft-tissue tumours. ICG was administered intravenously at a dose of 2 mg/kg over a period of 60 minutes on the day prior to surgery. The tumour stain rate and signal-to-background ratio of each tumour were post hoc analyzed. After tumour resection, the tumour bed was scanned to locate sites with fluorescence residuals, which were subsequently inspected and biopsied. Results. The overall tumour stain rate was 88% (30/34 patients), and specific stain rates included 90% for osteosarcomas and 92% for giant cell tumours. For malignant tumours, the overall stain rate was 94%, while it was 82% for benign tumours. The ICG tumour stain was not influenced by different pathologies, such as malignant versus benign pathology, the reception (or lack thereof) of neoadjuvant chemotherapies, the length of time between drug administration and surgery, the number of doses of denosumab for patients with giant cell tumours, or the tumour response to neoadjuvant chemotherapy. The overall accuracy rate of successfully predicting tumour residuals using fluorescence was 49% (23/47 pieces of tissue). The accuracy rate after en bloc resection was significantly lower than that after piecemeal resection (16% vs 71%; p < 0.001). Conclusion. A high percentage of bone and soft-tissue tumours can be stained by ICG and the tumour staining with ICG was stable. This approach can be used in both benign and malignant tumours, regardless of whether neoadjuvant chemotherapy is adopted. The technique is also useful to detect tumour residuals in the wound, especially in patients undergoing piecemeal resection. Cite this article: Bone Joint J 2023;105-B(5):551–558

Bone sarcomas are rare cancers and orthopaedic surgeons come across them infrequently, sometimes unexpectedly during surgical procedures. We investigated the outcomes of patients who underwent a surgical procedure where sarcomas were found unexpectedly and were subsequently referred to our unit for treatment. We identified 95 patients (44 intra-lesional excisions, 35 fracture fixations, 16 joint replacements) with mean age of 48 years (11 to 83); 60% were males (n = 57). Local recurrence arose in 40% who underwent limb salvage surgery versus 12% who had an amputation. Despite achieving local control, overall survival was worse for patients treated with amputation rather than limb salvage (54% vs 75% five-year survival). Factors that negatively influenced survival were invasive primary surgery (fracture fixation, joint replacement), a delay of greater than two months until referral to our oncology service, and high-grade tumours. Survival in these circumstances depends mostly on factors that are determined prior to definitive treatment by a tertiary orthopaedic oncology unit. Limb salvage in this group of patients is associated with a higher rate of inadequate marginal surgery and, consequently, higher local recurrence rates than amputation, but should still be attempted whenever possible, as local control is not the primary determinant of survival.

Cite this article: Bone Joint J 2014;96-B:665–72.

Aims

The aim of this study was to assess the safety and clinical outcome of patients with a femoral shaft fracture and a previous complex post-traumatic femoral malunion who were treated with a clamshell osteotomy and fixation with an intramedullary nail (IMN).

Aims

The aim of this study was to capture 12-month outcomes from a representative multicentre cohort of patients undergoing total ankle arthroplasty (TAA), describe the pattern of patient-reported outcome measures (PROMs) at 12 months, and identify predictors of these outcome measures.

Aims

The aim of this study was to evaluate the epidemiology and treatment of Perthes’ disease of the hip.

Aims. The aims of this study were to evaluate the long-term outcome of surgery for bone or soft-tissue metastases from renal cell carcinoma (RCC) and to determine factors that affect prognosis. Patients and Methods. Between 1993 and 2014, 58 patients underwent surgery for bone or soft-tissue metastases from RCC at our hospital. There were 46 men and 12 women with a mean age of 60 years (25 to 84). The mean follow-up period was 52 months (1 to 257). The surgical sites included the spine (33 patients), appendicular skeleton (ten patients), pelvis (eight patients), thorax (four patients), and soft tissue (three patients). The surgical procedures were en bloc metastasectomy in 46 patients (including 33 patients of total en bloc spondylectomy (TES)) and intralesional curettage in 12 patients. These patients were retrospectively evaluated for factors associated with prognosis. Results. The one-, three-, five-, ten-, and 15-year overall survival (OS) rates were 89%, 75%, 62%, 48%, and 25%, respectively. The median survival time (MST) was 127 months for en bloc metastasectomy and 54 months for intralesional curettage and bone grafting. The median survival time was 127 months for the spine, 140 months for lesions of the appendicular skeleton, and 54 months for the pelvis. Multivariate analysis showed that non-clear cell type RCC and metastases to more than two sites were independent risk factors for a poor prognosis. Conclusion. Patients with bone or soft-tissue metastases from a RCC have a reasonable prognosis, making surgical resection a viable option even in patients in whom the metastases are advanced. Cite this article: Bone Joint J 2018;100-B:1241–8

Aims

To achieve the functional benefits of the direct anterior (DA) approach and the fixation benefits of cemented replacement, this study combined the two techniques posing the following questions: does the limited access of the DA approach adversely affect the cement technique?; and does such a cementing technique reduce the incidence of cementless complications?

Aims. The surgical treatment of tuberculosis (TB) of the spine consists of debridement and reconstruction of the anterior column. Loss of correction is the most significant challenge. Our aim was to report the outcome of single-stage posterior surgery using bone allografts in the management of this condition. Patients and Methods. The study involved 24 patients with thoracolumbar TB who underwent single-stage posterior spinal surgery with a cortical bone allograft for anterior column reconstruction and posterior instrumentation between 2008 and 2015. A unilateral approach was used for 21 patients with active TB, and a bilateral approach with decompression and closing-opening wedge osteotomy was used for three patients with healed TB. Results. A median of 1.25 vertebrae were removed (interquartile range (IQR) 1 to 1.75) and the median number of levels that were instrumented was five (IQR 3 to 6). The median operating time was 280 minutes (IQR 230 to 315) and the median blood loss was 700 ml (IQR 350 to 900). The median postoperative kyphosis was 8.5° (IQR 0° to 15°) with a mean correction of the kyphosis of 71.6%. Good neurological recovery occurred, with only two patients (8%) requiring assistance to walk at a mean follow-up of 24 months (9 to 50), at which time there was a mean improvement in disability, as assessed by the Oswestry Disability Index, of 83% (90% to 72%). Conclusion. The posterior-only approach using cortical allografts for anterior column reconstruction achieved good clinical and radiological outcomes. Differentiation should be made between flexible (active) and rigid (healed) TB spine. Cite this article: Bone Joint J 2018;100-B:1208–13

Aims

The aims of the study were to analyze differences in surgical and oncological outcomes, as well as quality of life (QoL) and function in patients with ankle sarcomas undergoing three forms of surgical treatment, minor or major limb salvage surgery (LSS), or amputation.

Aims

Preoperative talar valgus deformity ≥ 15° is considered a contraindication for total ankle arthroplasty (TAA). We compared operative procedures and clinical outcomes of TAA in patients with talar valgus deformity ≥ 15° and < 15°.

Aims. The aim of this study was to describe the technique of distraction osteogenesis followed by arthrodesis using internal fixation to manage complex conditions of the ankle, and to present the results of this technique. Patients and Methods. Between 2008 and 2014, distraction osteogenesis followed by arthrodesis using internal fixation was performed in 12 patients with complex conditions of the ankle due to trauma or infection. There were eight men and four women: their mean age was 35 years (23 to 51) at the time of surgery. Bone healing and functional recovery were evaluated according to the criteria described by Paley. Function was assessed using the ankle-hindfoot scale of the American Orthopedic Foot and Ankle Society (AOFAS). Results. A solid fusion of the ankle and eradication of infection was achieved in all patients. A mean lengthening of 6.1 cm (2.5 to 14) was achieved at a mean follow-up of 25.2 months (14 to 37). The mean external fixation index (EFI) was 42 days/cm (33.3 to 58). The function was judged to be excellent in six patients and good in six patients. Bone results were graded as excellent in ten patients and good in two patients. The mean AOFAS score was 37.3 (5 to 77) preoperatively and 75.3 (61 to 82) at the final follow-up. Minor complications, which were treated conservatively, included pain, pin-tract infection, loosening of wires, and midfoot stiffness. Major complications, which were treated surgically included grade V pin-tract infection with inflammation and osteolysis, poor consolidation of the regenerate bone, and soft-tissue invagination. The reoperations required to treat the major complications included the exchange of pins and wires, bone grafting and invagination split surgery. Conclusion. The technique of distraction osteogenesis followed by arthrodesis using internal fixation is an effective form of treatment for the management of complex conditions of the ankle. It offers a high rate of union, an opportunity to remove the frame early, and a reduced EFI without infection or wound dehiscence. Cite this article: Bone Joint J 2018;100-B:755–60

Aims

The aim of this study is to evaluate the clinical results of operative intervention for femoral metastases which were selected based on expected survival and to discuss appropriate surgical strategies.

Aims

The Precice intramedullary limb-lengthening system has demonstrated significant benefits over external fixation lengthening methods, leading to a paradigm shift in limb lengthening. This study compares outcomes following antegrade and retrograde femoral lengthening in both adolescent and adult patients.

Aims

Many authors have reported a shorter treatment time when using trifocal bone transport (TFT) rather than bifocal bone transport (BFT) in the management of long segmental tibial bone defects. However, the difference in the incidence of additional procedures, the true complications, and the final results have not been investigated.

J. E. Lang, S. Mannava, A. J. Floyd, M. S. Goddard, B. P. Smith, A. Mofidi , T. M. Seyler, R. H. Jinnah. Robotic systems in orthopaedic surgery. J Bone Joint Surg Br 2011 93-B: 1296-1299

J. E. Lang, S. Mannava, A. J. Floyd, M. S. Goddard, B. P. Smith, A. Mofidi , T. M. Seyler, R. H. Jinnah. Robotic systems in orthopaedic surgery. J Bone Joint Surg Br 2011 93-B: 1296-1299

Bone allografts can be used in any kind of surgery involving bone from minor defects to major bone loss after tumour resection. This review describes the various types of bone grafts and the current knowledge on bone allografts, from procurement and preparation to implantation. The surgical conditions for optimising the incorporation of bone are outlined, and surgeon expectations from a bone allograft discussed

Streptomycin and the newer antibiotics have already belied the pessimistic agnosticism of 1947. In certain instances, notably in disease of the knee and hip and in some cases with draining sinuses, it appears that they are sufficient to produce a quiescence which may be a cure. For the rest it remains to map out in detail what has in part been explored. In particular it is essential to confirm how far antibiotics enable surgeons to treat tuberculosis upon the basic principles applicable to other infections of bone without fear of secondary infection: where there is diseased bone, to remove it: where there is pus, to relieve the tension and evacuate it. The surgeon fears not so much the infection itself as the inability of the tuberculous soil ordinarily to deal with secondary infection. With the control of the diseased soil the risk should be no greater than that of any other surgery of bone. The early case and the advanced case; age and site of disease; these and other variables must subdivide basic method. What is the best application of the new "combined operation" to a child of three with thoracic Pott's disease and a globular abscess? What is the wisest plan for a man of forty with old disease in his lumbar vertebrae and discharging sinuses? We begin to see what we could do. At the present the question still remains: What should we do?

Aims

Radiostereometric analysis (RSA) allows an extremely accurate measurement of early micromotion of components following arthroplasty.

Objectives

Unicompartmental knee arthroplasty (UKA) is a potential treatment for isolated bone on bone osteoarthritis when limited to a single compartment. The risk for revision of UKA is three times higher than for total knee arthroplasty (TKA). The aim of this review was to discuss the different revision options after UKA failure.

Aims

This study aims to assess first, whether mutations in the epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma (kRAS) genes are associated with overall survival (OS) in patients who present with symptomatic bone metastases from non-small cell lung cancer (NSCLC) and secondly, whether mutation status should be incorporated into prognostic models that are used when deciding on the appropriate palliative treatment for symptomatic bone metastases.

Aims

Our purpose was to determine the quality of current randomised controlled trials (RCTs) in hand surgery using standardised metrics.

Aims

Chronic osteomyelitis may recur if dead space management, after excision of infected bone, is inadequate. This study describes the results of a strategy for the management of deep bone infection and evaluates a new antibiotic-loaded biocomposite in the eradication of infection from bone defects.

Costoplasty can reduce the important cosmetic deformity of rib prominence in scoliosis but there are few objective reports of correction. We recorded the results of three objective methods of assessing back shape before and after short-segment costoplasty in 55 patients. We showed that significant improvement was maintained over a two-year follow-up period. Primary costoplasty at the time of scoliosis surgery (n = 35) achieved greater proportional correction than secondary costoplasty performed after fusion of the spine (n = 20). The rib segments removed at primary surgery provided enough bone for the autogenous graft; harvesting from the pelvis was unnecessary. We report a new classification of rib morphology which helps in planning the site and extent of costoplasty, and in predicting the possible correction

The systemic arterial pressure has been used as a guide for determining the susceptibility to surgical bleeding during controlled hypotensive anaesthesia. Arterial hypotension is not, however, necessarily accompanied by venous or intraosseous hypotension. The main source of bleeding during posterior spinal surgery is the bone and is venous rather than arterial. The intraoperative blood loss, the intraosseous pressure (IOP) within the first thoracic vertebral body, and the systemic arterial pressure were measured in 27 patients during cervical laminoplasty for spondylotic myelopathy. The intraoperative blood loss correlated significantly with the vertebral IOP (p = 0.0073, r = 0.499), but not with systemic arterial pressure, age, or body-weight. The systemic arterial pressure did not correlate with the vertebral IOP. The mean value of the mean arterial pressure throughout the operation varied between 74 and 110 mmHg. The findings suggest that the vertebral IOP parallels surgical bleeding during posterior spinal surgery under normotensive anaesthesia and that patients with a low arterial pressure do not necessarily have a low IOP

To assess the sustainability of our institutional bone bank, we calculated the final product cost of fresh-frozen femoral head allografts and compared these costs with the use of commercial alternatives. Between 2007 and 2010 all quantifiable costs associated with allograft donor screening, harvesting, storage, and administration of femoral head allografts retrieved from patients undergoing elective hip replacement were analysed.

From 290 femoral head allografts harvested and stored as full (complete) head specimens or as two halves, 101 had to be withdrawn. In total, 104 full and 75 half heads were implanted in 152 recipients. The calculated final product costs were €1367 per full head. Compared with the use of commercially available processed allografts, a saving of at least €43 119 was realised over four-years (€10 780 per year) resulting in a cost-effective intervention at our institution. Assuming a price of between €1672 and €2149 per commercially purchased allograft, breakeven analysis revealed that implanting between 34 and 63 allografts per year equated to the total cost of bone banking.

Cite this article: Bone Joint J 2014;96-B:1307–11

It is important to be able to identify patients with an increased risk of venous thromboembolism (VTE) in order to minimise the risk of an event. We investigated the incidence and risk factors for post-operative VTE in 168 consecutive patients with a malignancy of the lower limb. The period of study included ten months before and 12 months after the introduction of chemical thromboprophylaxis. All data about the potential risk factors were identified and classified into three groups (patient-, surgery- and tumour-related). The outcome measure was a thromboembolic event within 90 days of surgery.

Of the 168 patients, eight (4.8%) had a confirmed symptomatic deep-vein thrombosis and one (0.6%) a fatal pulmonary embolism. Of the 28 variables tested, age > 60 years, higher American Society of Anesthesiologists grade and metastatic tumour were independent risk factors for VTE. The overall rate of symptomatic VTE was not significantly different between patients who received chemical thromboprophylaxis and those who did not. Knowledge of these risk factors may be of value in improving the surgical outcome of patients with a malignancy of the lower limb.

Cite this article: Bone Joint J 2013;95-B:558–62.

We report our experience of staged revision surgery for the treatment of infected total elbow arthroplasty (TEA). Between 1998 and 2010 a consecutive series of 33 patients (34 TEAs) underwent a first-stage procedure with the intention to proceed to second-stage procedure when the infection had been controlled. A single first-stage procedure with removal of the components and cement was undertaken for 29 TEAs (85%), followed by the insertion of antibiotic-impregnated cement beads, and five (15%) required two or more first-stage procedures. The most common organism isolated was coagulase-negative Staphylococcus in 21 TEAs (62%).

A second-stage procedure was performed for 26 TEAs (76%); seven patients (seven TEAs, 21%) had a functional resection arthroplasty with antibiotic beads in situ and had no further surgery, one had a persistent discharge preventing further surgery.

There were three recurrent infections (11.5%) in those patients who underwent a second-stage procedure. The infection presented at a mean of eight months (5 to 10) post-operatively. The mean Mayo Elbow Performance Score (MEPS) in those who underwent a second stage revision without recurrent infection was 81.1 (65 to 95).

Staged revision surgery is successful in the treatment of patients with an infected TEA and is associated with a low rate of recurrent infection. However, when infection does occur, this study would suggest that it becomes apparent within ten months of the second stage procedure.

Cite this article: Bone Joint J 2013;95-B:1681–6.

Over a five-year period, adult patients with marginal impaction of acetabular fractures were identified from a registry of patients who underwent acetabular reconstruction in two tertiary referral centres. Fractures were classified according to the system of Judet and Letournel. A topographic classification to describe the extent of articular impaction was used, dividing the joint surface into superior, middle and inferior thirds. Demographic information, hospitalisation and surgery-related complications, functional (EuroQol 5-D) and radiological outcome according to Matta’s criteria were recorded and analysed. In all, 60 patients (57 men, three women) with a mean age of 41 years (18 to 72) were available at a mean follow-up of 48 months (24 to 206). The quality of the reduction was ‘anatomical’ in 44 hips (73.3%) and ‘imperfect’ in 16 (26.7%). The originally achieved anatomical reduction was lost in12 patients (25.8%). Radiologically, 33 hips (55%) were graded as ‘excellent’, 11 (18.3%) as ‘good’, one (1.7%) as ‘fair’ and 15 (25%) as ‘poor’. A total of 11 further operations were required in 11 cases, of which six were total hip replacements.

Univariate linear regression analysis of the functional outcome showed that factors associated with worse pain were increasing age and an inferior location of the impaction. Elevation of the articular impaction leads to joint preservation with satisfactory overall medium-term functional results, but secondary collapse is likely to occur in some patients.

Cite this article: Bone Joint J 2013;95-B:230–8.

We reviewed 59 bone graft substitutes marketed by 17 companies currently available for implantation in the United Kingdom, with the aim of assessing the peer-reviewed literature to facilitate informed decision-making regarding their use in clinical practice. After critical analysis of the literature, only 22 products (37%) had any clinical data. Norian SRS (Synthes), Vitoss (Orthovita), Cortoss (Orthovita) and Alpha-BSM (Etex) had Level I evidence. We question the need for so many different products, especially with limited published clinical evidence for their efficacy, and conclude that there is a considerable need for further prospective randomised trials to facilitate informed decision-making with regard to the use of current and future bone graft substitutes in clinical practice.

Cite this article: Bone Joint J 2013;95-B:583–97.

The treatment of substantial proximal femoral bone loss in young patients with developmental dysplasia of the hip (DDH) is challenging. We retrospectively analysed the outcome of 28 patients (30 hips) with DDH who underwent revision total hip replacement (THR) in the presence of a deficient proximal femur, which was reconstructed with an allograft prosthetic composite. The mean follow-up was 15 years (8.5 to 25.5). The mean number of previous THRs was three (1 to 8). The mean age at primary THR and at the index reconstruction was 41 years (18 to 61) and 58.1 years (32 to 72), respectively. The indication for revision included mechanical loosening in 24 hips, infection in three and peri-prosthetic fracture in three.

Six patients required removal and replacement of the allograft prosthetic composite, five for mechanical loosening and one for infection. The survivorship at ten, 15 and 20 years was 93% (95% confidence interval (CI) 91 to 100), 75.5% (95% CI 60 to 95) and 75.5% (95% CI 60 to 95), respectively, with 25, eight, and four patients at risk, respectively. Additionally, two junctional nonunions between the allograft and host femur required bone grafting and plating.

An allograft prosthetic composite affords a good long-term outcome in the management of proximal femoral bone loss in revision THR in patients with DDH, while preserving distal host bone.

We retrospectively reviewed 40 hips in 36 patients who had undergone acetabular reconstruction using a titanium Kerboull-type acetabular reinforcement device with bone allografts between May 2001 and April 2006. Impacted bone allografts were used for the management of American Academy of Orthopaedic Surgeons Type II defects in 17 hips, and bulk bone allografts together with impacted allografts were used for the management of Type III defects in 23 hips. A total of five hips showed radiological failure at a mean follow-up of 6.7 years (4.5 to 9.3), two of which were infected. The mean pre-operative Merle d’Aubigné score was 10 (5 to 15) vs 13.6 (9 to 18) at the latest follow-up. The Kaplan-Meier survival rate at ten years, calculated using radiological failure or revision of the acetabular component for any reason as the endpoint, was 87% (95% confidence interval 76.3 to 97.7). A separate experimental analysis of the mechanical properties of the device and the load-displacement properties of bone grafts showed that a structurally hard allograft resected from femoral heads of patients with osteoarthritis should be preferentially used in any type of defect. If impacted bone allografts were used, a bone graft thickness of < 25 mm was acceptable in Type II defects.

This clinical study indicates that revision total hip replacement using the Kerboull-type acetabular reinforcement device with bone allografts yielded satisfactory mid-term results.

We report a case of spontaneous physeal growth arrest of the distal femur in a nine-year-old child with Ewing’s sarcoma of the proximal femur treated with chemotherapy and endoprosthetic replacement. Owing to the extent of disuse osteoporosis at the time of surgery, the entire intramedullary canal up to the distal femoral physis was filled with cement. Three years later, the femur remained at its pre-operative length of 19 cm. Pre-operative calculations of further growth failed to account for the growth arrest, and the initial expandable growing prosthesis inserted has been revised to a longer one in order to address the leg-length discrepancy.

To our knowledge, this is the only reported case of distal femoral physeal growth arrest following cemented endoprosthetic replacement of the proximal femur.

We investigated the stability of seven Schatzker type II fractures of the lateral tibial plateau treated by subchondral screws and a buttress plate followed by immediate partial weight-bearing. In order to assess the stability of the fracture, weight-bearing inducible displacements of the fracture fragments and their migration over a one-year period were measured by differentially loaded radiostereometric analysis and standard radiostereometric analysis, respectively. The mean inducible craniocaudal fracture fragment displacements measured −0.30 mm (−0.73 to 0.02) at two weeks and 0.00 mm (−0.12 to 0.15) at 52 weeks. All inducible displacements were elastic in nature under all loads at each examination during follow-up. At one year, the mean craniocaudal migration of the fracture fragments was −0.34 mm (−1.64 to 1.51).

Using radiostereometric methods, this case series has shown that in the Schatzker type II fractures investigated, internal fixation with subchondral screws and a buttress plate provided adequate stability to allow immediate post-operative partial weight-bearing, without harmful consequences.

We have investigated the effectiveness of the transplantation of bone-marrow-derived mononuclear cells (BMMNCs) with interconnected porous calcium hydroxyapatite (IP-CHA) on early bone repair for osteonecrosis of the femoral head. We studied 22 patients (30 hips) who had osteonecrosis with a minimum follow-up of one year after implantation of BMMNCs. The mean age at surgery was 41 years (18 to 64) and the mean period of follow-up was 29 months (19 to 48). In a control group, cell-free IP-CHA was implanted into a further eight patients (9 hips) with osteonecrosis of the femoral head and the outcomes were compared.

A reduction in the size of the osteonecrotic lesion was observed subsequent to hypertrophy of the bone in the transition zone in the BMMNC group. In three patients in the treatment group progression to extensive collapse was detected. In the control group subtle bone hypertrophy was observed, but severe collapse of the femoral head occurred in six of eight hips.

In this limited study the implantation of BMMNCs and IP-CHA appears to confer benefit in the repair of osteonecrosis and in the prevention of collapse.

Thromboprophylaxis remains a controversial subject. A vast amount of epidemiological and trial data about venous thromboembolism has been published over the past 40 years. These data have been distilled and synthesised into guidelines designed to help the practitioner translate this extensive research into ‘evidence-based’ advice.

Guidelines should, in theory, benefit patient care by ensuring that every patient routinely receives the best prophylaxis; without guidelines, it is argued, patients may fail to receive treatment or be exposed to protocols which are ineffective, dangerous or expensive.

Guidelines, however, have not been welcomed or applied universally. In the United States, orthopaedic surgeons have published their concerns about the thromboprophylaxis guidelines prepared by the American College of Chest Physicians. In Britain, controversy persists with many surgeons unconvinced of the risk/benefit, cost/benefit or practicality of thromboprophylaxis. The extended remit of the recent National Institute of Clinical Excellence thromboprophylaxis guidelines has been challenged.

The reasons for this disquiet are addressed in this paper and particular emphasis is placed on how clinically-acceptable guidelines could be developed and applied.

The weight-bearing status of articular cartilage has been shown to affect its biochemical composition. We have investigated the topographical variation of sulphated glycosaminoglycan (GAG) relative to the DNA content of the chondrocyte in human distal femoral articular cartilage.

Paired specimens of distal femoral articular cartilage, from weight-bearing and non-weight-bearing regions, were obtained from 13 patients undergoing above-knee amputation. After papain enzyme digestion, spectrophotometric GAG and fluorometric DNA assays assessed the biochemical composition of the samples. The results were analysed using a paired t-test.

Although there were no significant differences in cell density between the regions, the weight-bearing areas showed a significantly higher concentration of GAG relative to DNA when compared with non-weight-bearing areas (p = 0.02).

We conclude that chondrocytes are sensitive to their mechanical environment, and that local loading conditions influence the metabolism of the cells and hence the biochemical structure of the tissue.

The use of a navigation system in musculoskeletal tumour surgery enables the integration of pre-operative CT and MRI images to generate a precise three-dimensional anatomical model of the site and the extent of the tumour.

We carried out six consecutive resections of musculoskeletal tumour in five patients using an existing commercial computer navigation system. There were three women and two men with a mean age of 41 years (24 to 47). Reconstruction was performed using a tumour prosthesis in three lesions and a vascularised fibular graft in one. No reconstruction was needed in two cases. The mean follow-up was 6.9 months (3.5 to 10). The mean duration of surgery was 28 minutes (13 to 50). Examination of the resected specimens showed clear margins in all the tumour lesions and a resection that was exactly as planned.

We report the mid-term results of a new patellofemoral arthroplasty for established isolated patellofemoral arthritis. We have reviewed the experience of 109 consecutive patellofemoral resurfacing arthroplasties in 85 patients who were followed up for at least five years.

The five-year survival rate, with revision as the endpoint, was 95.8% (95% confidence interval 91.8% to 99.8%). There were no cases of loosening of the prosthesis. At five years the median Bristol pain score improved from 15 of 40 points (interquartile range 5 to 20) pre-operatively, to 35 (interquartile range 20 to 40), the median Melbourne score from 10 of 30 points (interquartile range 6 to 15) to 25 (interquartile range 20 to 29), and the median Oxford score from 18 of 48 points (interquartile range 13 to 24) to 39 (interquartile range 24 to 45). Successful results, judged on a Bristol pain score of at least 20 at five years, occurred in 80% (66) of knees. The main complication was radiological progression of arthritis, which occurred in 25 patients (28%) and emphasises the importance of the careful selection of patients. These results give increased confidence in the use of patellofemoral arthroplasty.

We carried out a prospective randomised study to evaluate the blood loss in 60 patients having a total knee arthroplasty and divided randomly into two equal groups, one having a computer-assisted procedure and the other a standard operation. The surgery was carried out by a single surgeon at one institution using a uniform approach. The only variable in the groups was the use of intramedullary femoral and tibial alignment jigs in the standard group and single tracker pins of the imageless navigation system in the tibia and femur in the navigated group.

The mean drainage of blood was 1351 ml (715 to 2890; 95% confidence interval (CI) 1183 to 1518) in the computer-aided group and 1747 ml (1100 to 3030; CI 1581 to 1912) in the conventional group. This difference was statistically significant (p = 0.001). The mean calculated loss of haemoglobin was 36 g/dl in the navigated group versus 53 g/dl in the conventional group; this was significant at p < 0.00001.

There was a highly significant reduction in blood drainage and the calculated Hb loss between the computer-assisted and the conventional techniques. This allows the ordering of less blood before the operation, reduces risks at transfusion and gives financial saving. Computer-assisted surgery may also be useful for patients in whom blood products are not acceptable.