Sciatic nerve injury remains a significant and devastating complication of total hip arthroplasty. Incidence as quoted in the literature ranges from 0.08% in primary joint replacement to 7.5% in revision arthroplasty. While as urgent exploration is recommended for nerve palsies associated with pain, management of sciatic nerve palsy with little or no pain is still controversial. In light of this, many patients with persistent palsies are often not referred to our specialist centre until after 6 months post-injury. The aim of this study was to review the outcomes of surgical intervention in patients presenting with sciatic nerve palsy more than 6 months after total hip arthroplasty.

This retrospective cohort study identified 35 patients who underwent exploration and neurolysis of the affected sciatic nerve. All patients had documented follow-up at 1, 3, 6, 12 and 18 months to assess sensory and motor recovery. Patients were scored for sensory and motor function in the tibia and common personal nerve divisions, pre and post-operatively. The scoring system devised by Kline et al (1995) was used. Pre-operative electrophysiology was also reviewed.

We found a statistically significant functional recovery following neurolysis of the sciatic nerve (p<0.01). A statistically significant relationship was also found between time to neurolysis and recovery of tibial nerve function (p = 0.02), such that greater delay to neurolysis was associated with poorer recovery. There was no significant relationship between time to neurolysis and recovery of common peroneal nerve function (p = 0.28).

Our results indicate that the neurolysis of the sciatic nerve, six months or more post injury is associated with functional recovery. We feel that without surgical exploration this clinical improvement would not have occurred. Therefore, we believe that neurolysis plays a vital role at any stage of sciatic nerve injury. However, early presentation to a specialist unit is associated with better outcomes.

The articulating surface replacement (ASR) XL stemmed total hip replacement and ASR resurfacing hip systems were recalled by DePuy due to a high prevalence of early failure. The ASR XL has a greater failure rate than the ASR resurfacing, which has been increasingly attributed to wear and corrosion at the taper interface between the female taper surface of the femoral head and the male taper (trunnion) of the femoral stem. The aim of this study was to quantify the prevalence and severity of taper corrosion in retrieved ASR XL hip components.

A peer-reviewed subjective corrosion scoring system was used to quantify corrosion in a consecutive series of the 50 ASR XL hip components (head components – n=44; femoral stems – n=6) at our retrieval centre. Bearing surface wear (femoral head and acetabular cup combined) was quantified and a value of <5 microns was defined as low-wearing. Subsequent profilometry analysis was undertaken in the low-wearing hips to quantify material loss from the taper interface.

90% of components showed evidence of corrosion, with at least moderate corrosion observed in 58%. There were 17 low-wearing hips which had a median material loss from the taper interface of 3.51mm³ (range: 0.612–9.443). The median linear depth of material loss was 33μm (range: 8.5–78.0). No relationship was observed between taper corrosion and serum cobalt (r=0.204, p=0.2712) or chromium (r=0.146, p=0.432) metal ions.

Wear and material loss from metal-on-metal (MoM) hips is associated with pseudotumour formation and adverse soft-tissue reactions. We have shown that taper corrosion is extremely common in failed ASR XL hips and that wear occurs in the same degree of magnitude as at the bearing surface also occurs at the taper interface. Therefore our findings support the emerging concept of ‘taper failure’, whereby the taper is the predominate reason for failure of MoM hips. Future work must determine the relative contributions of the bearing surface and the taper interface to serum cobalt and chromium metal ion levels.

Corrosion at the taper interface between the femoral head and the femoral stem is well described in metal-on-polyethylene (MoP) hips but previously was undetermined in large diameter head metal-on-metal (LHMoM) hips. The high failure rate of the articulating surface replacement (ASR) XL hip system has been partly attributed to susceptibility to corrosive damage at the taper interface. It was not known if other hip manufacturers are liable to taper corrosion. Therefore the aim of this study was to quantify the prevalence and severity of taper corrosion in LHMoM hips and compare corrosion across five different current generation manufacturers.

Taper corrosion was analysed in a consecutive series of the five most common hip types at our retrieval centre: ASR XL, DePuy (n=49); Birmingham hip resurfacing, Smith & Nephew (n=33), Durom, Zimmer (n=31), M2a Magnum, Biomet (n=14) and Cormet, Stryker (n=10). A four-scale peer-reviewed qualitative corrosion scoring system was used to quantify corrosion (none, mild, moderate and severe).

Evidence of corrosion was observed in 86% of components, with at least moderate corrosion observed in 61%. No difference in corrosion was observed between the ASR XL and the other manufacturers (p=0.202). There was still no difference seen when all manufacturers were compared individually (p=0.363). A positive correlation was observed between corrosion and femoral head diameter (r=0.224, p=0.021). However no relationship was observed with implantation time (r=0.163, p=0.118).

Our study indicates that taper corrosion is common in LHMoM hips and affects all hip types equally. The clinical significance of this finding is that all hip types will be susceptible to the complications of corrosion, such as third body wear and osteolysis. Furthermore recent reports indicate that corrosive debris released from the taper interface may play a role in the formation of pseudotumours and adverse soft-tissue reactions. We found that larger femoral head sizes showed greater corrosion, which suggests that high torque increases fretting corrosion of the taper interface. Future work must determine the optimum femoral head size and investigate the chemical composition of the corrosive debris.

In metal-on-metal (MoM) total hip arthroplasty, the taper interface is where the femoral head (female taper surface) attaches to the trunnion (male taper) of the femoral stem. Corrosion is well reported in metal-on-polyethylene hips but little is known about taper corrosion in MoM devices. The aim of this study was to quantify corrosion in modern-generation stemmed MoM hip systems and gain insight into the nature of the underlying corrosive attack.

Taper corrosion was quantified in 161 failed MoM components (head components n=128; femoral stem n=33) from nine hip types with the use of a qualitative subjective scoring system. An unanticipated finding on preliminary inspection of the hips was a region on the female taper surface that contained ridges that directly corresponded with the ridged microthread on the trunnion. The ridges were not present on unimplanted (control) female taper surfaces and therefore a novel four-scale subjective scoring system was devised to quantify the prevalence and severity of this ‘imprinting’ phenomenon.

Evidence of corrosion was observed in 81% (131/161) of components, with at least moderate corrosion observed in 58% (94/161). Corrosion was greater on the female taper surface than on the male taper (p=0.034) and the two scores were associated (r=0.784, p=0.001). Imprinting affected all manufacturers and was observed in 64% (82/128) of head components. The corrosion and imprinting scores were strongly correlated (r=0.694, p=0.001). Corrosion was largely confined to the area of the female taper interface where imprinting had occurred i.e. the region that had been in contact with the trunnion microthread. Scanning electron microscopy showed evidence of fretting corrosion and substantial mechanical wear within the ridged region on the female taper surface.

Our study indicates that MoM hips are susceptible to taper corrosion. We believe it occurs by a process of “mechanically-assisted crevice corrosion,” involving the following sequence of events: joint fluid enters the taper junction as a result of pumping of fluid along the machined microthread of the trunnion. This results in galvanic corrosion of the anodic surface (the cobalt-chromium femoral head or taper sleeve). The pattern of corrosion of the head taper is determined by the surface profile of the screw thread of the trunnion, thus leaving an imprinted appearance. Historically the ridged microthread was introduced to trunnions to minimise the risk of burst fracture of ceramic heads. However this study indicates that the ridges are detrimental in MoM hips by causing extensive mechanical wear. Thus the possibility that cobalt-chrome and ceramic femoral head components require different trunnion designs needs urgent investigation.

Background

Complex tibial fractures are difficult to treat. The costs associated with hospitalization can be substantial, yet it is unknown how these vary depending upon the type of implant used. There have been multiple studies on economics of tibial fractures but none of these studies actually focussed on costing of illizarov and taylor spatial frames. We discuss the cost analysis of 200 tibial fractures treated with illizarov or taylor spatial frames. The purpose of this study was to compare the cost of treatment of complex tibial fractures with reimbursement given to the hospital in treating such injuries.

Aim

Chronic osteomyelitis still remains challenging and expensive to treat in spite of advances in antibiotics and operative techniques. We present our experience with free muscle flap after radical debridement of chronic osteomyelitis, performed as a single stage procedure.

AIM

Chronic osteomyelitis still remains challenging and expensive to treat inspite of advances in antibiotics and operative techniques.

We present our experience with free muscle flap after radical debridement of chronic osteomyelitis, performed as a single stage procedure.

Introduction

Viscosupplementation is used widely to provide symptomatic relief to patients with knee OA. This study aimed to compare the efficacy and safety of the standard (3×2ml) and single (1×6ml) dosing regimens of hylan G-F 20.

Introduction

The policy of treating open fractures within 6 hrs can result in complex operations being performed under sub optimal conditions. The purpose of this study was to determine the association between time to initial debridement and rate of infection in high energy (Grade III) open fractures of Tibia.

Aim: To report the clinical, functional and radiological outcome of consecutive primary hip arthroplasties using large diameter (36mm and above) ceramic bearing couples. We believe this to be one of the first reported series in the UK.

Methods: We prospectively reviewed 319 consecutive primary THA using fully HAC coated acetabular shell and fully HAC coated stem (JRI Ltd) in 302 patients, with minimum follow-up of 12 months. A Biolox-Delta ceramic liner with an 18 deg taper and Biolox-Delta ceramic head (36mm and 40mm) were used in all cases, which were performed in one institution by 3 surgeons. None were lost to follow-up. Clinical outcome was measured using Harris, Charnley Oxford, EuroQol EQ-5D scores. Radiographs were systematically analysed for implant position, loosening, migration, osteolysis. Return to sports and hobbies were recorded.

Results: Mean age was 64.9 yrs (11–82yrs). There were no dislocations. 50–62mm acetabular shells were used. 36 mm head was used in 96% of cases. No acetabular revisions were performed for aseptic loosening. Other re-operations were for infection (1), peri-prosthetic fractures (1). The mean Harris and Oxford scores were 95 (88–97) and 14.1 (12–33) respectively. The Charnley score was 5.7 (5–6) for pain, 5.8 (4–6) for movement and 5.9 (4–6) for mobility. There was a significant improvement in the range of movement of the hip. There was no migration of acetabular component. Acetabular radiolucencies were present around one shell. No acetabular liner wear was demonstrated in CT Scans. Mean inclination was 47.4deg(37–65). Mean EQ- 5D description scores and health thermometer scores were 0.84 (0.71–0.92) and 88 (66–96). With an end point of definite or probable loosening, the probability of survival was 100%. Overall survival with removal or repeat revision of either component for any reason as the end point was 99.1%.

Conclusion: The results of this study show an excellent clinical and functional outcome and support the use of a fully coated prosthesis with ceramic bearing couples. We envisage to monitor and prospectively report the long-term outcome of this series of patients.

Introduction: Numerous studies have been carried out to assess the efficacy of tranexamic acid on intra and post operative blood loss and its implications. Many of these studies conclude that there is a need to study the effects of tranexamic acid on actual post Operative blood transfusion, thromboembolic events and hospital stay.

We analyzed the effects of Tranexamic acid on Intra- operative blood loss, post Operative haemoglobin and haematocrit drop, blood transfusion requirement, incidence of deep vein thrombosis and hospital stay in Patients undergoing Total hip arthroplasty.

Methods: Prospective case control study involving 50 patients (25 in each category, ASA class I to III) operated by a single consultant. Patient were given single dose of Intra venous Tranexamic Acid (10 mg/kg,10 minutes pre-incision) and Intra operative blood loss was compared to control group analyzing dry and wet swab weights and irrigation fluid. The actual haemoglobin drop, blood transfusion requirement, average length of stay in hospital and incidence of DVT were noted.

Results: There was 30% reduction in intra operative blood loss in the study group. None of the other parameters show evidence of a statistically significant difference between the groups. The average hospital stay was 7 days in both the groups.

Discussion: We found out that Tranexamic acid makes little difference in terms of actual haemoglobin and haematocrit drop, blood transfusion requirement and hospital stay. Our study didn’t show any rise in deep vein thrombosis in treatment group. The only difference it made was reduction of intraoperative blood loss by 30%. To the best of our knowledge, ours is the only study which combines all these parameters.