Richard P. Baker

Total hip arthroplasty and hemiarthroplasty in mobile, independent patients with a displaced intracapsular fracture of the femoral neck. A randomized, controlled trial.

BACKGROUNDnHemiarthroplasty and total hip arthroplasty are commonly used to treat displaced intracapsular fractures of the femoral neck, but each has disadvantages and the optimal treatment of these fractures remains controversial.nnnMETHODSnIn the present prospectively randomized study, eighty-one patients who had been mobile and lived independently before they had sustained a displaced fracture of the femoral neck were randomized to receive either a total hip arthroplasty or a hemiarthroplasty. The mean age of the patients was seventy-five years. Outcome was assessed with use of the Oxford hip score, and final radiographs were assessed.nnnRESULTSnAfter a mean duration of follow-up of three years, the mean walking distance was 1.17 mi (1.9 km) for the hemiarthroplasty group and 2.23 mi (3.6 km) for the total hip arthroplasty group, and the mean Oxford hip score was 22.3 for the hemiarthroplasty group and 18.8 for the total hip arthroplasty group. Patients in the total hip arthroplasty group walked farther (p=0.039) and had a lower (better) Oxford hip score (p=0.033) than those in the hemiarthroplasty group. Twenty of thirty-two living patients in the hemiarthroplasty group had radiographic evidence of acetabular erosion at the time of the final follow-up. None of the hips in the hemiarthroplasty group dislocated, whereas three hips in the total hip arthroplasty group dislocated. In the hemiarthroplasty group, two hips were revised to total hip arthroplasty and three additional hips had acetabular erosion severe enough to indicate revision. In the total hip arthroplasty group, one hip was revised because of subsidence of the femoral component.nnnCONCLUSIONSnTotal hip arthroplasty conferred superior short-term clinical results and fewer complications when compared with hemiarthroplasty in this prospectively randomized study of mobile, independent patients who had sustained a displaced fracture of the femoral neck.

Maximum temperatures of 89°C recorded during the mechanical preparation of 35 femoral heads for resurfacing

Background and purpose We noticed that our instruments were often too hot to touch after preparing the femoral head for resurfacing, and questioned whether the heat generated could exceed temperatures known to cause osteonecrosis. Patients and methods Using an infra-red thermal imaging camera, we measured real-time femoral head temperatures during femoral head reaming in 35 patients undergoing resurfacing hip arthroplasty. 7 patients received an ASR, 8 received a Cormet, and 20 received a Birmingham resurfacing arthroplasty. Results The maximum temperature recorded was 89°C. The temperature exceeded 47°C in 28 patients and 70°C in 11. The mean duration of most stages of head preparation was less than 1 min. The mean time exceeded 1 min only on peripheral head reaming of the ASR system. At temperatures lower than 47°C, only 2 femoral heads were exposed long enough to cause osteonecrosis. The highest mean maximum temperatures recorded were 54°C when the proximal femoral head was resected with an oscillating saw and 47°C during peripheral reaming with the crown drill. The modified new Birmingham resurfacing proximal femoral head reamer substantially reduced the maximum temperatures generated. Lavage reduced temperatures to a mean of 18°C. Interpretation 11 patients were subjected to temperatures sufficient to cause osteonecrosis secondary to thermal insult, regardless of the duration of reaming. In 2 cases only, the length of reaming was long enough to induce damage at lower temperatures. Lavage and sharp instruments should reduce the risk of thermal insult during hip resurfacing.

Histology of failed metal-on-metal hip arthroplasty; three distinct sub-types

The histological specimens from 29 failed metal-on-metal (MoM) hip arthroplasties treated at our institution were reviewed. Five patients had a failed MoM total hip arthroplasty (THA), and 24 patients a failed hip resurfacing. Clinical and radiographic features of each hip were correlated with the histological findings. We report three major histological subtypes. Patients either have a macrophage response to metal debris, a lymphocytic response (ALVAL) or a mixed picture of both. In addition we observe that the ALVAL response is located deep within tissue specimens, and can occur in environments of low wear debris. The macrophage response is limited to the surface of tissue specimens, with normal underlying tissue. Patients with subsequently confirmed ALVAL underwent revision surgery sooner than patients whose histology confirms a macrophage response (3.8 vs. 6.9 years p<0.05). Both histological subtypes (ALVAL and macrophage dominant) are responsible for abnormal soft tissue swellings.

Pneumatosis intestinalis an increasingly common radiological finding, benign or life-threatening? A case series.

This case series reviews two cases where elderly patients were found to have pneumatosis intestinalis on imaging. The two clinical presentations differed from one another, however, both were managed conservatively to good effect. In case one the patient presented with abdominal pain, a change in bowel habit and weight loss. In case two the patient presented with problematic diarrhoea, reduced oral intake, lethargy and weight loss. Both patients were haemodynamically stable and neither had an abnormal abdominal examination. Case 2 was started on oral metronidazole and by day 11 of treatment there was resolution of the pneumatosis on her abdominal X-ray and her diarrhoea had settled. These two cases illustrate the benefit of conservative management and avoidance of unnecessary surgical intervention in primary pneumatosis intestinalis. However, it is important to distinguish between these benign causes of pneumatosis intestinalis and those which are life-threatening in which surgery may be necessary.

Stem compatibility for cement-in-cement femoral revision: an in vitro study

Cement-in-cement femoral component revision is a useful and commonly practised technique. Onerous and hazardous re-shaping of the original cement mantle is required if the new stem does not seat easily. Furthermore, without removing the entirety of the original cement mantle, the freedom to alter anteversion or leg length is difficult to predict preoperatively. We present data from in vitro experiments testing the compatibility of the top cemented stems according to UK registry figures (NJR 2013). This data augments preoperative planning by indicating which revision stems require minimal or no cement reshaping when being inserted into another stems mantle. We also present the maximum shortening and anteversion that can be achieved without reshaping the original cement mantle.

Thermal damage during humeral reaming in total shoulder resurfacing

Introduction: Total shoulder resurfacing (TSR) provides a reliable solution for the treatment of glenohumeral arthritis. It confers a number of advantages over traditional joint replacement with stemmed humeral components, in terms of bone preservation and improved joint kinematics. This study aimed to determine if humeral reaming instruments produce a thermal insult to subchondral bone during TSR. Patients and Methods: This was tested in vivo on 13 patients (8 with rheumatoid arthritis and 5 with osteoarthritis) with a single reaming system and in vitro with three different humeral reaming systems on saw bone models. Real-time infrared thermal video imaging was used to assess the temperatures generated. Results: Synthes (Epoca) instruments generated average temperatures of 40.7°C (SD 0.9°C) in the rheumatoid group and 56.5°C (SD 0.87°C) in the osteoarthritis group (P = 0.001). Irrigation with room temperature saline cooled the humeral head to 30°C (SD 1.2°C). Saw bone analysis generated temperatures of 58.2°C (SD 0.79°C) in the Synthes (Epoca) 59.9°C (SD 0.81°C) in Biomet (Copeland) and 58.4°C (SD 0.88°C) in the Depuy Conservative Anatomic Prosthesis (CAP) reamers (P = 0.12). Conclusion: Humeral reaming with power driven instruments generates considerable temperatures both in vivo and in vitro. This paper demonstrates that a significant thermal effect beyond the 47°C threshold needed to induce osteonecrosis is observed with humeral reamers, with little variation seen between manufacturers. Irrigation with room temperature saline cools the reamed bone to physiological levels and should be performed regularly during this step in TSR.

Gluteal fascial transposition for trochanteric bursitis

We report a new surgical technique for refractory trochanteric bursitis, performed in 43 patients between May 1988 and December 2003. Fourteen patients had developed trochanteric bursitis after primary total hip arthroplasty (THA), six after revision THA, 17 for no definable reason (idiopathic) and seven after trauma. Follow-up ranged from six months to 15 years (mean five years). Outcome was measured by the patients symptoms at interview and whether the patient would have had the procedure again. Outcome depended on aetiology: 100% of traumatic, 88% of idiopathic and 64% after primary THA were successful. All operations after revision THA were unsuccessful. Transposition of the gluteal fascia is indicated in patients with idiopathic, traumatic and post primary THA trochanteric bursitis, but not after revision THA. (Hip International 2005; 15: 212-7).

Fat embolism: a rare cause of perioperative renal transplant dysfunction

Fat embolism is a recognised complication of bony injury and orthopaedic surgery, commonly involving the long bones and pelvis. We report on the case of a 68-year-old renal transplant recipient who developed acute kidney injury following surgical stabilisation of metastatic carcinoma of the acetabulum and replacement of the proximal femur. A CT renal angiogram demonstrated a large fat embolus in the inferior vena cava (IVC) and left iliac veins below the level of IVC filter, with impaired renal perfusion. The risks of open or endovascular lipothrombectomy were felt to outweigh the potential benefits. The patient was managed with systemic anticoagulation and prepared for transplant failure. Subsequently, there was spontaneous improvement in urine output and 4u2009months postoperatively her transplant function had returned to her baseline level and this has remained stable at 1u2009year postsurgery.

Introductory editorial to 25th Anniversary edition

We have commissioned reviews from experts in their respective fields in hip surgery to cover a broad and interesting range of topics. As the 16th EFORT congress in Prague’s main theme is orthopaedic infection, we too start with 4 articles on prosthetic joint infection. Our 1st paper concentrates on the diagnosis of the infected hip arthroplasty. This is followed by a review of the singlestage strategy surgery from the ENDO-Klinik, Hamburg, where Buchholz popularised the procedure. The Vancouver arthroplasty group who invented the PROSTALAC technique review the 2-stage revision strategy. Finally, the Swiss patient-adapted regime is reviewed in our 4th paper. Wrightington review the current evidence for hip arthroscopy and its applications. Hip resurfacing, its history and current application is reviewed by Dr. Harlan Amstutz, who has dedicated his career to perfecting the technique. Professor Morlock highlights the missed opportunities from the literature in relation to the foreseeable taper problems from metal-on-metal hip replacements. The London implant retrieval unit reviews the metal-on-metal problem drawing on their vast experience of analysis of failed implants. We have also included the best paper presented at the recent European Hip Society meeting in Stockholm 2014. Dr. Eastwood and colleagues have performed novel work looking at Osteoclastogenesis-related cytokines and its relationship to osteolysis in metal-on-metal total hip replacements. Revision techniques are reviewed with contributions from Nijmegen where impaction bone grafting was introduced and perfected. Non-biological acetabular reconstructions are reviewed by Dr. Ran Schwarzkopf for the most challenging of acetabular defects. Mr. Wyatt looks further at custom made acetabular prostheses for severe acetabular defects. The Mayo clinic share with us their experience of femoral revision. Finally, the dislocating hip is reviewed by Mr. Jones from Cardiff University Hospital. I hope you find the excellent articles in this commemorative edition both informative and enjoyable.