Objective: Considering the high incidence and misdiag-nostic rate of developmental dysplasia of hip (DDH) in China, some patients suffer from severe pain in the hip at early age, and a total hip arthroplasty would be necessary. To our knowledge, the intermediate-term(equal to or more than five years) results of total hip arthroplasty (THA) in patients with osteoarthritis secondary to developmental dysplasia of the hip has not been studied in China previously. This study evaluated more than five-year clinical and radiographic outcomes associated with total hip arthroplasty (THA) in a consecutive series of patients with osteoarthritis secondary to developmental dysplasia of the hip.

Methods: From February 2000 to July 2002, 55 patients (69 hips) underwent THA in our hospital were involved in this study. Clinical outcomes were evaluated according to Harris evaluate score. Components migration, periprosthetic bone changes, the polyethylene wear rate were measured radiologically. Kaplan-Meier analysis was performed to evaluate the survival of the acetabular and femoral component. End point was obvious radiological loosening or revision either or both of the acetabular and femoral component for any reason.

Results: Forty-five patients (57 hips) were followed up at least 5 years. The average preoperative Harris hip score was (46.19±18.01) points, which improved to (91.78±3.52) points at final follow-up. There were 48 excellent hips (84.21%), 7 good hips (12.28%), 2 fair hips (3.51%) and no poor hip. There is no significant difference of Harris score between the dysplasia group, the low dislocation group and the high dislocation group (P> 0.05, ANOVA). The mean polyethylene liner wear rate was (0.27±0.14)mm/year. According to the statistical relevant analysis, the wear rate of the polyethylene liner had relationship with the age(r=−0.288, P=0.040), the abnormal abduction angle of the acetabular cup (r=0.317, P=0.023)and the osteolysis rate (r=0.573, P=0.026), while had no significant relationship with the thickness of the polyethylene liner (P=0.326), gender(P=0.097), DDH classification(P=0.958) and the Harris score(P=0.598). There are 5 pelvic osteolysis and 8 proximal femoral osteolysis. Using loosening or revision as the end point for failure, the survival rate of both components was 1.0 (95% confidence interval, 0.98–1.00).

Conclusions: In conclusion, improved surgical technique and design in the components provided favorable mid-term results in Chinese patients with osteoarthritis secondary to developmental dysplasia of the hip. Bulk autogenous or allografting is not needed if more than 70% of the acetabular component is covered by host bone. Although the Asia life style includes more squatting and cross-legged, the results of this series in Chinese population are comparable to the satisfactory results of other reported DDH series whose patients are mainly western people. The mid-term results of THA are equivalent in the group of patients with dysplasia, low dislocation, and high dislocation types both in ace-tabular and femoral components. However, the authors continue to be anxious about the high rate of liner wear and osteolysis, which deserve the necessary long-term follow-up.

Introduction

The enhanced recovery after surgery (ERAS) concept in arthroplasty surgery has led to a reduction in postoperative length of stay in recent years. Patients with prolonged length of stay (PLOS) add to the burden of a strained NHS. Our aim was to identify the main reasons.

Objectives

High failure rates of metal-on-metal hip arthroplasty implants have highlighted the need for more careful introduction and monitoring of new implants and for the evaluation of the safety of medical devices. The National Joint Registry and other regulatory services are unable to detect failing implants at an early enough stage. We aimed to identify validated surrogate markers of long-term outcome in patients undergoing primary total hip arthroplasty (THA).

We performed a meta-analysis of modern total joint replacement (TJR) to determine the post-operative mortality and the cause of death using different thromboprophylactic regimens as follows: 1) no routine chemothromboprophylaxis (NRC); 2) Potent anticoagulation (PA) (unfractionated or low-molecular-weight heparin, ximelagatran, fondaparinux or rivaroxaban); 3) Potent anticoagulation combined (PAC) with regional anaesthesia and/or pneumatic compression devices (PCDs); 4) Warfarin (W); 5) Warfarin combined (WAC) with regional anaesthesia and/or PCD; and 6) Multimodal (MM) prophylaxis, including regional anaesthesia, PCDs and aspirin in low-risk patients. Cause of death was classified as autopsy proven, clinically certain or unknown. Deaths were grouped into cardiopulmonary excluding pulmonary embolism (PE), PE, bleeding-related, gastrointestinal, central nervous system, and others (miscellaneous). Meta-analysis based on fixed effects or random effects models was used for pooling incidence data.

In all, 70 studies were included (99 441 patients; 373 deaths). The mortality was lowest in the MM (0.2%) and WC (0.2%) groups. The most frequent cause of death was cardiopulmonary (47.9%), followed by PE (25.4%) and bleeding (8.9%). The proportion of deaths due to PE was not significantly affected by the thromboprophylaxis regimen (PA, 35.5%; PAC, 28%; MM, 23.2%; and NRC, 16.3%). Fatal bleeding was higher in groups relying on the use of anticoagulation (W, 33.8%; PA, 9.4%; PAC, 10.8%) but the differences were not statistically significant.

Our study demonstrated that the routine use of PA does not reduce the overall mortality or the proportion of deaths due to PE.

We conducted a systematic review and meta-analysis of randomised controlled trials comparing cross-linked with conventional polyethylene liners for total hip replacement in order to determine whether these liners reduce rates of wear, radiological evidence of osteolysis and the need for revision. The MEDLINE, EMBASE and COCHRANE databases were searched from their inception to May 2010 for all trials involving the use of cross-linked polyethylene in total hip replacement. Eligibility for inclusion in the review included the random allocation of treatments, the use of cross-linked and conventional polyethylene, and radiological wear as an outcome measure. The pooled mean differences were calculated for bedding-in, linear wear rate, three-dimensional linear wear rate, volumetric wear rate and total linear wear. Pooled risk ratios were calculated for radiological osteolysis and revision hip replacement. A search of the literature identified 194 potential studies, of which 12 met the inclusion criteria. All reported a significant reduction in radiological wear for cross-linked polyethylene.

The pooled mean differences for linear rate of wear, three-dimensional linear rate of wear, volumetric wear rate and total linear wear were all significantly reduced for cross-linked polyethylene. The risk ratio for radiological osteolysis was 0.40 (95% confidence interval 0.27 to 0.58; I² = 0%), favouring cross-linked polyethylene. The follow-up was not long enough to show a difference in the need for revision surgery.

The effects of the method of fixation and interface conditions on the biomechanics of the femoral component of the Birmingham hip resurfacing arthroplasty were examined using a highly detailed three-dimensional computer model of the hip. Stresses and strains in the proximal femur were compared for the natural femur and for the femur resurfaced with the Birmingham hip resurfacing. A comparison of cemented versus uncemented fixation showed no advantage of either with regard to bone loading. When the Birmingham hip resurfacing femoral component was fixed to bone, proximal femoral stresses and strains were non-physiological. Bone resorption was predicted in the inferomedial and superolateral bone within the Birmingham hip resurfacing shell. Resorption was limited to the superolateral region when the stem was not fixed. The increased bone strain observed adjacent to the distal stem should stimulate an increase in bone density at that location. The remodelling of bone seen during revision of failed Birmingham hip resurfacing implants appears to be consistent with the predictions of our finite element analysis.