The thickness of the cement mantle surrounding total hip replacements has been used to predict the incidence of aseptic loosening. However little work has been done regarding the significance of the cement mantle distal to the tip of the femoral prosthesis. Results are reported of a radiographic audit study analyzing the thickness of the distal cement column in primary total hip replacement.

In this study the thickness of cement distal to the tip of the femoral prosthesis was measured from 80 post-op AP radiographs taken over a period of 5 months using both the PACS system and plain film x-rays. The mean thickness was 2cm (max 8cm) (min −1.8cm) with a std dev of 1.7cm.

This study demonstrated the wide variation in the thickness of the distal cement column achieved by surgeons. It also highlighted the fact that while 2–5mm is the generally accepted optimal cement mantle surrounding the femoral prosthesis, there is little guidance from the literature with regards the optimal thickness of the cement mantle distal to the tip of the femoral prosthesis. Further work requires to be undertaken to determine the optimal thickness of cement in this area, as well as changes in local surgical practice to ensure the optimal thickness of cement distally is consistently achieved. A re-audit of this work after alterations of surgical technique is desirable.

Introduction

The Western Infirmary/Gartnavel General Hospital orthopaedic department is geographically located next to the Beatson Oncology Centre, a specialist regional oncology unit. Pathological femoral fractures are the commonest reason for surgical intervention in patients referred from the Beatson and we have used them as a model to establish the demographic data, referral patterns, treatment results, and survival characteristics in such a group of patients.

Limb salvage surgery includes all of the surgical procedures designed to accomplish removal of a malignant tumour and reconstruction of the limb in order to achieve an acceptable oncological, functional, and cosmetic result. The aim of this study was to evaluate the functional outcome following endoprosthetic replcament for primary upper & lower extremity musculoskeletal neolplasms.

Between 1983 and 2004, we found 68 patients from the Scottish Tumor Register having had an endoprosthetic reconstruction for upper and lower-extremity malignant musculoskeletal tumours, of which 32 were alive for performing functional assessment (lower extremity-26, upper extremity-6). The clinical, radiological and oncological outcomes were evaluated. The functional outcome was measured by the Musculoskeletal Tumor Society and Toronto Extremity Salvage Score.

The average follow-up was 59 months (range, 1 to 21 years). There were 19 female and 13 male patients. These were anatomically distributed as around the knee (n=18 cases), hip (n=8) and shoulder (n=4). The most common diagnosis was chondrosarcoma (n=10) and osteosarcoma (n=11). Most of the patients were completely satisfied with their condition, with a decreased walking distance as the only notable restriction. There was no correlation between the functional outcome and the type or site of resection. Complications occurred in ten cases, including two cases of aseptic loosening and one case each of recurrent instability, sciatic nerve palsy and femoral nerve palsy. The median functional score using the Musculoskeletal Tumour Society system was 56% and Toronto Extremity Salvage Score was 72%.

Limb salvage for malignant musculoskeletal tumours continues to pose therapeutic and oncological challenges with considerable functional issues, but the good function and local tumour control in most patients justifies its continued use.

Introduction: Infection is a serious complication of joint arthroplasty. Detection of low-grade prosthetic infection can be difficult, with major implications on the subsequent treatment, cost and patient morbidity. We evaluated the effectiveness of Polymerase Chain Reaction (PCR) in detecting infection in patients undergoing arthroplasty revision surgery.

Methods: Ninety-one consecutive patients (92 joints) undergoing revision THA or TKA were assessed prospectively. Preoperative assessment included clinical examination, blood tests and plain radiographs. At revision, tissue samples were sent for microbiology and histology. Cultures, using blood culture bottles, and PCR were performed on the synovial fluid. Diagnosis of infection relied on the surgeon’s opinion encompassing the clinical presentation, the results of various investigations and the intraoperative findings. Infected arthroplasties underwent a 2-stage revision. Post-operatively patients were followed up at regular intervals for a minimum of 2 years.

Results: Twelve (13%) joints were infected. Histology was positive for infection in 11 cases, tissue cultures were positive in 12 and PCR was positive in 32 cases. Intraoperative tissue cultures had sensitivity 0.75, specificity 0.96, positive predictive value 0.75 and negative predictive value 0.96; histology had sensitivity 0.92, specificity 1, positive predictive value 1 and negative predictive value 0.99 and PCR had a sensitivity 0.92, specificity 0.74, positive predictive value 0.34 and negative predictive value 0.98. At 2 years no patient showed evidence of infection.

Discussion: PCR is a sensitive method of diagnosing prosthetic infection but has poor specificity. False positive results may be due to contamination in theatre or in the laboratory. Positive results in apparently non-infected cases could be due to the detection of low virulence organisms, a small number of bacteria or a strong host immune response. Bacterial fragments and non-culturable forms of bacteria may also be responsible.

Conclusion: PCR was not helpful as a screening test for prosthetic infection. Cultures and histology combined with the surgeon’s clinical judgment remain the gold standard.

Introduction: Metal-on-metal hip resurfacing arthroplasty is one option for young and active patients with advanced hip disease. Intraoperative or immediate postoperative femoral neck fractures complicating a metal-on-metal hip resurfacing is a well described complication as a result of neck notching and stress shielding of the femoral head. The literature contains very little evidences on the conservative mode of treatment for peri-prosthetic fractures following the index operation with a favourable and an unfavourable outcome. We report a case of femoral neck fracture incurred three months after metal-on-metal hip resurfacing resulting in a varus malunion.

Case report: A 55 year old lady underwent metal-on-metal surface hip replacement for advanced osteoarthritis of the left hip. The implants used were Cormet 2000 uncemented 50mm dual coated cup and cemented 44mm femoral head. Intraoperative bone quality was good and no technical difficulties were encountered. She was admitted three months later with a painful left hip after sustaining a fall. The radiograph confirmed left periprosthetic femoral neck fracture with resurfacing prosthesis in situ. She was scheduled for elective revision surgery of the femoral component. The patient elected to go home with the intention of getting readmitted. Initially lost to follow-up, she self referred after 30 months of her fracture with shortening and persistent painful limp. The clinical examination revealed 1.5 cm of true limb shortening with restricted terminal range of abduction and rotational movements. The radiographs revealed a varus malunited fracture with proximal migration of greater trochanter. The acetabular component was well fixed in situ. She is awaiting revision surgery by conversion to conventional total hip arthroplasty.

Conclusion: We report the first case of a malunited femoral neck fracture following metal-on-metal hip resurfacing operation. Femoral neck fractures can heal in these cases but poor compliance and resultant failure to closely observe the patient may have contributed to such an unfavourable outcome. These complications may be prevented by increased compliance and communication with the patients. At the same time, the hospital management and professional staff should be aware of such potential problems to prevent their recurrence.

The aim of this study was to evaluate whether duration of surgery correlates with the survival and final outcome of the patient with metastatic bone disease.

Between 1999 and 2002, 23 consecutive patients with impending or complete pathological fractures of the femur due to metastatic bone disease caused by variety of malignancies or an unknown primary were reviewed. These fractures were treated with intramedullary fixation in the form of long intramedullary hip screw, long Gamma nail or AO nail. These patients were followed up clinically and radiologically until death from the primary disease.

The results obtained demonstrate a mean survival time between 9 days to 12 months. Pain relief was achieved in 90% patients. Ambulatory status was improved in 47% patients. The postoperative course was complicated by four technical and five systemic complications. Intramedullary nailing is a safe and effective method in the treatment of metastatic bone disease. It provides good functional result with pain relief and improved mobility. The operating time does not predictably correlate with the survival and final outcome of the patient.

Breast carcinoma is the most common cause for bony metastases. Skeletal complications in women with meta-static breast carcinoma often occur multiple times in a single patient and significantly contribute to the patient morbidity. We describe a 62 year old lady with a known metastatic breast carcinoma who presented with simultaneous quadruple extremity diaphyseal long bone fractures after a trivial fall. To the author’s best knowledge, similar report has never been previously described in the literature.

The wish and general condition of the patient, and concurrent occurrence of four long bone fractures dictated the non-operative mode of treatment in this case.Where the life expectancy is assumed to be less than six weeks, the multidisciplinary team should give careful consideration on selection of best treatment choice between simultaneous or sequential surgical fixation of multiple long bone fractures and conservative palliative treatment. With treatment suited for an end-of-life circumstance, the educational lesson for dissemination to the readers is that in a patient where there is an extremely high likelihood of imminent perioperative mortality after sustaining quadruple extremity diaphyseal proximal long bone fractures simultaneously, conservative palliative treatment should be primarily considered over an aggressive operative fixation.

Introduction: Metal-on-metal hip resurfacing arthroplasty is recommended for younger patients with advanced hip disease who are likely to outlive a conventional primary total hip arthroplasty and wish to be reasonably active. Intraoperative or immediate postoperative femoral neck fracture is a well described technical complication as a result of notching and stress shielding of the femoral head. We report two cases of femoral neck fracture incurred eight to fifteen months following the index operation.

Case 1: A 47 year old lady was admitted after sustaining a fall. Radiograph confirmed left femoral neck fracture with resurfacing prosthesis in situ. She underwent metal-on-metal surface hip replacement 15 months ago for advanced osteoarthritis. The periprosthetic fracture was treated by revising the femoral component, using Eurocone cormet modular endo head 44mm size. At one year follow up, she was able to mobilise unassisted and had a good range of movements.

Case 2: A 52 year old gentleman presented with a painful right hip. While walking in the supermarket, he suddenly felt a click in the right hip. Radiograph confirmed right femoral neck fracture with resurfacing prosthesis in place. The metal-on-metal surface hip replacement was performed 8 months previously for advanced avascular necrosis. His medical history was significant for epilepsy. The Femoral component was revised, using Eurocone cormet modular endo head 52mm. He made a satisfactory progress at 18 months follow up since his periprosthetic fracture.

Conclusion: We recommend that patient selection should be given prime importance before embarking on metal on metal surface hip replacement. The surgeons’ factors are meticulous technique in preventing neck notching and femoral head fixation in varus angulation. Revising femoral component, using large head and leaving resurfaced cups in place should be considered as mode of treatment. Large multicentric trials are needed to evaluate the exact incidence of periprosthetic fractures in metal on metal hip resurfacing

Introduction: Infection constitutes a serious complication of joint arthroplasty, with an incidence of 1–2% after primary arthroplasty and even higher after revision procedures. Detection of low-grade infection in a prosthetic joint can often be very difficult, with huge implications on the subsequent treatment, cost and patient morbidity. Revision of an unrecognised infected arthroplasty may lead to less satisfactory results in a high proportion of cases. We utilized Polymerase Chain Reaction, a molecular biology technique to detect bacterial DNA from the synovial fluid of patients undergoing revision surgery, in comparison with conventional infection detection techniques.

Methods: We prospectively assessed 81 patients undergoing revision arthroplasty (67 hips and 14 knees). Each patient was pre-operatively assessed clinically and radiologically. ESR and CRP results were noted. During revision, synovial fluid and tissue cultures were obtained and antibiotics were given only after the specimens were taken. Standard microbiology and histology study were done on tissue samples. In addition Polymerase Chain Reaction study was performed on the synovial fluid. In this method, DNA is extracted from the bacterial cell; it is polymerised and finally visualized by gel electrophoresis. Post-operatively patients were followed up at regular intervals. Diagnosis of infection included correlation between clinical, radiological and laboratory investigations along with intra-operative findings, tissue culture and histology results and a period of postoperative follow up of 12 to 36 months.

Results: Eleven (13.58%) of the 81 cases that had revision arthroplasty were clinically infected. Polymerase chain reaction was positive in 30 cases, tissue cultures were positive in 8 cases and histology was positive in 10 cases for infection. PCR showed sensitivity and specificity of 0.92 and 0.72 respectively. Tissue culture showed sensitivity and specificity of 0.72 and 0.81 respectively. Histology showed sensitivity and specificity of 0.9 and 1 respectively.

Discussion: Twenty out of 30 PCR positive cases did not show any clinical evidence of infection. It is unclear whether this represents contamination during surgery or in the PCR lab. Alternatively this may represent true positive PCR results in cases with low bacterial count or bacteria growing within a biofilm that can be detected only by ultrasonication of the implant and immunofluorescence methods. PCR could also be detecting non-culturable forms of bacteria or bacterial fragments.

Conclusion: PCR has high sensitivity and low specificity for detection of bacterial DNA. The combination of tissue cultures and histology can still provide a reliable diagnosis of infection.

Background: Revision hip arthroplasty in the presence of extensive proximal femoral bone loss constitutes a major challenge. Several reconstruction alternatives have been introduced to deal with the problem of severe proximal bone loss. One of the techniques widely used is bridging the bone defect with the use of a distally fixing implant. The Link- MP reconstruction prosthesis is such a diaphyseal-fixing stem and we report on the early experience with its use.

Methods: The prosthesis has a modular design that allows restoration of hip biomechanics, femoral anteversion and leg length. It is made of a Titanium alloy with a micro-porous surface. The distal part (the stem) has a conical shape that allows cementless anchoring in the femoral diaphysis and it also has 8 or 10 longitudinal grooves, which provide rotational stability.

We report on the early results of its use, mean follow-up 30 months, (range, 9–54 months). Between 1997 and 2001, 32 hip revisions using the Link MP reconstruction prosthesis were performed in 31 patients. There were 13 females and 18 males with a mean age of 65 years (range 35 – 82). The indication for the revision operation was aseptic loosening in twenty-one cases, septic loosening in six and periprosthetic fracture in five cases. Cancellous bone allografts were used in 25 patients. Patients with proven infection were treated by a two-stage procedure.

Results: The mean Merle d’ Aubigne score increased from 6.8 preoperatively to 14.1 postoperatively and there was radiographic evidence of bone regeneration in the proximal femur in 80% of the patients. There were two intraoperative femoral fractures, which didn’t necessitate more than an extension of the partial weight bearing period and healed without complications. No stem was re-revised.

Conclusions: The early results with the use of the Link MP reconstruction prosthesis are encouraging, as shown by the improved patient functional status, the low incidence of complications and the observed proximal femoral bone regeneration.

The incidence of infection remains 1–2% after primary total joint arthroplasty and even higher after revision procedures in spite of advances in prophylactic antibiotics and clean air operating theatre environment. Detection of low-grade infection in a prosthetic joint can often be very difficult. None of the investigations available so far have 100% sensitivity and specificity. This has huge implications on the subsequent treatment, cost and patient morbidity. Revision of an unrecognized infected arthroplasty may lead to less satisfactory results in a high proportion of cases. We utilized Polymerase Chain Reaction, a molecular biology technique to detect bacterial DNA from the synovial fluid of patients undergoing revision surgery.

We prospectively assessed 70 patients undergoing revision arthroplasty (57 hips and 13 knees). Each patient was pre operatively assessed clinically and radiologically. ESR and CRP results were noted. During revision, synovial fluid and tissue cultures from capsule, bone and bone-cement interface were obtained. None of the patients received pre or intra operative antibiotics till the specimens were taken. Standard microbiology and histology study were done on tissue samples. In addition Polymerase Chain Reaction study was done on the synovial fluid. In this method, DNA is extracted from the bacterial cell, it is polymerized and finally visualized by gel electrophoresis. Post operatively patients were followed up at regular intervals.

Diagnosis of infection included correlation between clinical, radiological and laboratory investigations along with intraoperative findings, tissue culture and histology results and a period of post operative follow up (12 months to 36 months).

Six (8%) of the 70 cases that had revision arthroplasty were clinically infected. Polymerase chain reaction was positive in 25 cases, tissue cultures were positive in 5 cases and histology was positive in 5 cases for infection. PCR showed sensitivity and specificity of 83% and 69% respectively. Tissue culture showed sensitivity and specificity of 83% and 100% respectively. Histology showed sensitivity and specificity of 83% and 100% respectively.

20 out of 25 PCR positive cases did not show any clinical evidence of infection. It is unclear whether this represents contamination during surgery or in the PCR lab. Alternatively this may represent true positive PCR results in cases with low bacterial count that can be detected by ultrasonication of implant and immunofluorescence methods. PCR is more sensitive in detection of bacterial DNA. However it has low specificity and combination of tissue cultures and histology can still provide a reliable diagnosis of infection.

Therapy against Methicillin resistant Staphylococcus aureus (MRSA) infection is mainly restricted to the glycopeptide agents (vancomycin and teicoplanin), which require parenteral administration. At present oral antibiotic therapy against MRSA infection is not available. Linezolid is a recently introduced oxazolidinone synthetic antibiotic which acts by inhibiting the initiation of bacterial protein synthesis. It is effective against MRSA, glycopeptide resistant enterococci and all pneumococci irrespective of their penicillin or macrolide resistance. It has excellent oral bioavailability however, there are no data on the penetration of linezolid into osteoarticular tissues. This aim f this study was to measure the concentration of Linezolid in osteoarticular tissues after oral and intravenous administration.

Ten patients undergoing primary total knee replacements for osteoarthritis or rheumatoid arthritis were included in the study. Linezolid was given orally 600mg BD dose for 2 days prior to operation and a final IV 600mg dose 1h before induction on the day of operation. Intra-operatively at 30min after induction, blood, synovial fluid, synovium, muscle and bone samples were collected, processed and assayed for Linezolid concentration. The assay was performed by High Performance Liquid Chromatography (HPLC) method at Antimicrobial Research Laboratory, Westmead Hospital, Bristol.

High concentrations of Linezolid, above the Minimum Inhibitory Concentration (MIC≤ 4) were obtained all sites. Mean (± SD) concentrations for different tis- were: serum 23.0 (6.5) mg/L, synovial fluid 20.1 .4) mg/L, synovium 18.0 (5.6) mg/kg, muscle 18.5 (6.6) bone 8.5 (3.9) mg/kg

Treatment of Methicillin resistant Staphylococcus (MRSA) infections in bone and native or pros- joints is complex and costly. It requires prolonged parenteral and oral antibiotic combination therapy in addition to aggressive surgical debridement. The MICs Linezolid for staphylococci, pneumococci and streptococci are in a range from 0.5 to 2 mg/L whereas MIC enterococci is constant at 4mg/L. A two to six fold increased bioavailability of Linezolid was observed compared to its desired MIC. This study indicates that Linezolid penetrates osteoarticular tissues in sufficient concentration. Linezolid may prove to be an effective or intravenous therapy for serious bone and joint infections with multi-resistant gram-positive bacteria.