Adverse reactions to metal debris in metal-on-polyethylene total hip arthroplasty using a titanium-molybdenum-zirconium-iron alloy stem.

We report a series of three patients who underwent uncemented total hip arthroplasty with a modular titanium-molybdenum-zirconium-iron stem and a cobalt-chrome-molybdenum head on an ultra-high molecular weight highly cross-linked polyethylene liner bearing. All three cases subsequently developed pain and adverse reaction to metal debris, leading to revision of the implants within thirty-six months. They were subsequently found to have hypersensitivity to cobalt or chromium. However where tested, blood metal ion levels were within MHRA guideline limits. Corrosion was noted at the taper-trunnion junction. It is possible, that the multi alloy head-neck combination may lead to corrosion. Hypersensitivity to metal ions may result to ARMD at lower metal ion levels. The use of ceramic heads may help avoid this risk.

Effect of acetabular orientation on stress distribution of highly cross-linked polyethylene liners.

Several case reports have documented the fracture of highly cross-linked polyethylene (HCLPE) liners used in total hip arthroplasty (THA). Although uncommon, fractured liners result in considerable morbidity for patients and require revision surgery. One postulated mechanism that leads to this type of implant failure is malorientation of the acetabular component. The purpose of this study was to investigate the effect of acetabular orientation on the stress distribution of HCLPE liners used in THA by means of finite element analysis. Three-dimensional models of a commonly used HCLPE liner were created corresponding to 12 different acetabular component orientations (inclination ranging from 20° to 70° and version ranging from 20° of retroversion to 40° of anteversion). A static stress analysis of the finite element models was performed under conditions simulating peak gait loads. The results of the analysis revealed that excessive inclination and extremes of version were associated with an increase in peak stress magnitudes. The locations of peak stress also were found to lie within the rim notch and locking ring groove regions, which were consistent with the fracture locations reported in published case reports. Therefore, the acetabular component should be oriented carefully during implantation to reduce the risk of rim loading and subsequent liner fracture. In addition, an alternative liner design may further help reduce stress risers and risk of fracture.

Osteoid osteoma.

Osteoid osteomas consist of a nidus with surrounding sclerotic bone. The differential diagnosis covers a wide range of conditions due to the variable presentation of osteoid osteoma. The natural history is for regression to occur within 6 to 15 years with no treatment; however, this can be reduced to 2 to 3 years with the use of aspirin and non-steroidal anti-inflammatory drugs. Computed tomography-guided percutaneous techniques, including trephine excision, cryoablation, radiofrequency ablation, and laser thermocoagulation, are described.

Outcomes of total hip arthroplasty in the octogenarian population.

BACKGROUND: The outcomes of total hip arthroplasty (THA) in the elderly population are uncertain. With the rapid expansion of this population group, this study aims to determine whether increasing age affects the outcomes of THA by utilising the largest patient cohort and follow-up period within the literature. PATIENTS AND METHODS: All patients of 80 years and over who underwent primary THA between 1994 and 2004 at the authors' institution were compared to a cohort aged under 80 with the same diagnoses and during the same time period. Mean follow-up time was 5.9 years with a select group being reviewed at year 10. RESULTS: Pain scores were comparable at year five, whilst mean Harris hip scores were significantly lower in the octogenarians. Median hospital stay was three days longer in the elderly group. Complication rates were also higher (38.1% cf 28.7%) however fewer cases of revision were noted (1.4% cf 3.8%). Patient satisfaction was comparable between groups. CONCLUSION: This study suggests pain improvement, low revision rates and high satisfaction are sufficient to justify THA in the elderly population.

Total knee arthroplasty in the elderly: does age affect pain, function or complications?

BACKGROUND: TKA is one of the most commonly performed procedures in the elderly, yet whether age influences postoperative pain, function, and complication rates is not fully understood for this group. This is because the current literature has limited followup, small sample sizes, and no comparator group. QUESTIONS/PURPOSES: We therefore asked if increasing age adversely affects postoperative pain, Knee Society Scores(©), and complication rates. METHODS: We retrospectively reviewed all 438 patients 80 years or older who underwent primary TKA between 1995 and 2005. We established a comparator group of 2754 patients younger than 80 years. We assessed pain, the Knee Society Score(©) (KSS), and the Knee Society Function Score(©) (KSFS). The number and type of complications were recorded and those graded 2 or more using the classification of Dindo et al. were analyzed. Minimum followup was 5 years (mean, 6 years; range, 5-15.5 years). RESULTS: We found no difference in pain scores at 3, 5, and 10 years between the two groups. The KSS was comparable between groups at Year 5, but the KSFS was lower in the octogenarians. Major complications rates were higher in the octogenarian group (19% versus 15%). CONCLUSIONS: When compared with younger patients, octogenarians can expect comparable pain relief and KSS but lower function and more complications.

Management of periacetabular bone loss in revision hip arthroplasty.

The goals of acetabular revision surgery are to restore the anatomy and achieve stable fixation for the new acetabular component. The existing bone stock and the type of defect are determining factors in the surgical decision making. When necessary, and especially in younger patients, attempts should be made to restore the bone stock by grafting. The advent of modern reconstruction options, like the trabecular metal revision system and the cup-cage construct, provide more options in addressing the management of severe defects. Trabecular metal has a porosity similar to bone and provides an environment more favorable to bone graft remodeling than conventional metals. We present an overview of our experience and current approach to acetabular revision. In addition, we report our preliminary results with trabecular metal cups and trabecular metal cup-cage constructs used in conjunction with bone graft for addressing major bone defects.

Proximal femoral allograft treatment of Vancouver type-B3 periprosthetic femoral fractures after total hip arthroplasty. Surgical technique.

BACKGROUND: Periprosthetic femoral fractures following total hip arthroplasty are becoming more prevalent. When a fracture occurs in a femur with substantial proximal bone deficiency, the surgical options for revision are limited. One option includes the use of a proximal femoral allograft. METHODS: We retrospectively assessed the results and complications of the use of a proximal femoral allograft to treat twenty-five Vancouver type-B3 periprosthetic fractures in twenty-four patients. The mean duration of follow-up was 5.1 years. Clinical results were graded with use of the Harris hip score. Radiographs were assessed for evidence of trochanteric union, host-allograft union, allograft resorption, and component loosening or fracture. Failure of the procedure was defined as the need for revision surgery requiring graft removal. RESULTS: The mean postoperative Harris hip score was 70.8. At the time of the final follow-up, twenty-one of the twenty-four patients reported no or mild pain and twenty-three patients were able to walk; fifteen required a walking aid. The greater trochanter united in seventeen of the twenty-five hips (68%), and osseous union of the allograft to the host femur occurred in twenty hips (80%). There was mild graft resorption in four hips and moderate graft resorption in two. Four (16%) of the twenty-five hips required repeat revision. CONCLUSIONS: The use of a proximal femoral allograft for the treatment of a Vancouver type-B3 periprosthetic femoral fracture can provide a satisfactory result in terms of pain relief and function at five years.

Surgical options for articular defects of the knee.

Cartilage and osteochondral defects of the knee can in most cases be treated with total knee replacement in the elderly population. However, these lesions pose a difficult treatment problem in the younger patient. A number of surgical options are available today to address this increasingly common condition and each has its own indications and limitations. This article reviews debridement and microfracture, fixation, metallic spacing devices, autologous chondrocyte implantation, osteochondral autograft transplantation, fresh cadaveric allografts and osteotomies. In addition, possible future developments are discussed.

Prediction of Cobb angle in idiopathic adolescent scoliosis.

We did a prospective study of 291 children and adolescents with idiopathic scoliosis to identify possible correlations between clinical (scoliometer value, age, height) and radiographic (Cobb angle, Nash-Moe rotation, Risser iliac apophysis classification) parameters to predict the curve angle. There was a statistically significant correlation between thoracic, thoracolumbar, and lumbar scoliometer values and the thoracic, thoracolumbar, and lumbar Cobb angles, respectively (Pearson's r-0.685, 0.572, and 0.677, respectively). There was a statistically significant correlation between Cobb angle in the thoracic, thoracolumbar, and lumbar spine and the patients' age and height. Mathematical formulas that predict the Cobb angle of thoracic, thoracolumbar, and lumbar scoliosis using the scoliometer measurements are reported.

Greek versions of the Oswestry and Roland-Morris Disability Questionnaires.

Disability questionnaires are increasingly used for clinical assessment, outcome measurement of treatment and research methodology of low back pain. Their use in different countries and cultural groups must follow certain guidelines for translation and cross-cultural adaptation. The translation of such an instrument must be tested for its reliability and validity to be applied and to allow comparability of data. The Oswestry Disability Index and the Roland-Morris Disability Questionnaire are two disability questionnaires most commonly used as outcome measures in patients with low back pain. The two questionnaires were translated for use with the Greek population, were back translated and tested, and became available in a final version. The Greek versions of the Oswestry Disability Index and the Roland-Morris Disability Questionnaire were tested in 697 patients with low back pain. Internal consistency reliability for the Greek translation of the Oswestry Disability Index and the Roland-Morris Disability Questionnaire reached a Cronbach's alpha coefficient of 0.833 and 0.885 respectively. Face validity and content validity were ensured. Concurrent validity was assessed using a six-point pain scale as a criterion. The correlation of both scales was significant. The Greek translation of these disability questionnaires provided reliable and valid instruments for the evaluation of Greek-speaking patients with low back pain.

Multiple level noncontiguous fractures of the spine.

From 1970 to 2000, 81 patients with noncontiguous fractures of the spine were evaluated. Of these 81 patients, 36 had a neurologic deficit. Sixty-six patients with stable injuries were treated conservatively, whereas 15 patients with unstable injuries required surgical stabilization. There was no neurologic deterioration either in the patients who had surgical stabilization or in the patients who were treated conservatively. Thirteen patients with an A score on the American Spinal Injury Association neurologic impairment scale did not improve and had a high mortality rate (61.5%). Although multiple level noncontiguous fractures of the spine are uncommon, they constitute a threat to neurologic function, and therefore warrant radiographic evaluation of the entire spine with multiple injuries.