James R. Berstock

Mortality after total hip replacement surgery: A systematic review

Total hip replacement causes a short-term increase in the risk of mortality. It is important to quantify this and to identify modifiable risk factors so that the risk of post-operative mortality can be minimised. We performed a systematic review and critical evaluation of the current literature on the topic. We identified 32 studies published over the last 10 years which provide either 30-day or 90-day mortality data. We estimate the pooled incidence of mortality during the first 30 and 90 days following hip replacement to be 0.30% (95% CI 0.22 to 0.38) and 0.65% (95% CI 0.50 to 0.81), respectively. We found strong evidence of a temporal trend towards reducing mortality rates despite increasingly co-morbid patients. The risk factors for early mortality most commonly identified are increasing age, male gender and co-morbid conditions, particularly cardiovascular disease. Cardiovascular complications appear to have overtaken fatal pulmonary emboli as the leading cause of death after hip replacement. Cite this article: Bone Joint Res 2014;3:175–82.

A systematic review and meta-analysis of complications following the posterior and lateral surgical approaches to total hip arthroplasty.

INTRODUCTION Total hip arthroplasty is one of the most commonly performed orthopaedic procedures. Despite this, medical evidence to inform the choice of surgical approach is lacking. Currently in the UK, the two most frequently performed approaches to the hip are the posterior and the direct lateral. METHODS This systematic review was performed according to Cochrane guidelines following an extensive search for prospective controlled trials published in any language before January 2014. Of the 728 records identified from searches, 6 prospective studies (including 3 randomised controlled trials) involving 517 participants provided data towards this review. FINDINGS Compared with the lateral approach, the posterior approach conferred a significant reduction in the risk of Trendelenburg gait (odds ratio [OR]: 0.31, p=0.0002) and stem malposition (OR: 0.24, p=0.02), and a non-significant reduction in dislocation (OR: 0.37, p=0.16) and heterotopic ossification (OR: 0.41, p=0.13). Neither approach conferred a functional advantage. We draw attention to the paucity of evidence and the need for a further randomised trial.

Surgical approach and patient-reported outcomes after total hip replacement.

Background Previous research has mainly focused on how factors such as surgical approach might affect implant survivorship and the incidence of complications. Given the increasing interest in patient-reported outcomes, the purpose of this study is to explore whether surgical approach is associated with patient-reported pain, function, and satisfaction at 1–3 years after primary total hip replacement (THR). Methods Details of surgical factors were collated from operation notes for all consecutive patients at our centre from 2004–2006. All patients were mailed a questionnaire 1–3 years following surgery that collected WOMAC pain and function scores and the Self-Administered Patient Satisfaction Scale for Primary Hip and Knee Arthroplasty. Of the eligible 1,315 patients, 911 patients returned a completed questionnaire (69% response rate). Multivariable fractional logit models were used to identify whether surgical approach was associated with outcome scores. Results Surgical approach was found to be a significant predictor of patient-reported outcomes at 1–3 years after surgery, even after controlling for patient-specific factors. A posterior approach was associated with better scores on all three outcome measures. On average, predicted outcome scores for a typical patient with a posterior approach were between 3.5 and 7.2 percentage points higher than an equivalent patient with an anterolateral approach. Interpretation These findings suggest that clinical decisions concerning surgical approach may have an observable impact on patient-reported levels of pain, function, and satisfaction following THR.

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.

Trunnion corrosion: what surgeons need to know in 2018

Aims To present a surgically relevant update of trunnionosis. Materials and Methods Systematic review performed April 2017. Results Trunnionosis accounts for approximately 2% of the revision total hip arthroplasty (THA) burden. Thinner (reduced flexural rigidity) and shorter trunnions (reduced contact area at the taper junction) may contribute to mechanically assisted corrosion, exacerbated by high offset implants. The contribution of large heads and mixed metallurgy is discussed. Conclusion Identifying causative risk factors is challenging due to the multifactorial nature of this problem.

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.

A radiographic comparison of femoral offset after cemented and cementless total hip arthroplasty

Restoring femoral offset during total hip arthroplasty is important. Femoral offset and leg lengths are inextricably linked by the caput-collum-diaphysis (CCD) angle of the implant being used. We investigate the restoration of offset and leg lengths using the radiographs of a consecutive series of patients following implantation with either a high CCD angled cementless, or an anatomical CCD angled cemented femoral component. Although our data suggests that we are able to restore femoral offset and leg lengths using either device, we recommend additional caution when using non-anatomical high CCD angled implants.

Letter to the Editor: Not the Last Word: Safety Alert: One in 200 Knee Replacement Patients Die Within 90 Days of Surgery

W e enjoyed reading the column by Dr. Bernstein [1], but we believe knee replacement is considerably safer than suggested by the author. Three large cohort studies were used to estimate a 90-day mortality of 0.6% (2559 total deaths among 428,574 patients), or one in 200, as suggested in the title. Crucially, the author omitted the time period of data collection for his calculation. Katz and colleagues [6] reported mortality among Medicare beneficiaries using data collected during an 8-month period in 2000. Mahomed and colleagues [8] also studied Medicare beneficiaries receiving TKA during the year 2000 [8]. SooHoo and colleagues [11] studied patients receiving TKA in California from 1991 to 2001. Dr. Bernstein’s ‘‘back-of-the-envelope meta-analysis’’ estimate of mortality, therefore, pertains to data collected exclusively prior to 2001. A considerable temporal decline in mortality after TKA has been demonstrated within other large cohort studies of mortality after TKA. Sing and colleagues [10] used data from the Mayo clinic registry of 12,484 TKAs to show that 90-day mortality fell from 0.62% in the period 1994 to 1996, to 0.31% in the period 2006 to 2008. Hunt and colleagues [4] also observed a reduction in 45-day mortality from 0.37% in 2003, to 0.20% in 2011 in a registry study of 467,779 total knee replacements, even after adjusting for small differences in age and gender during the time period of observation [4]. A smaller study by Huddleston and colleagues [3] (including 2033 TKAs) identified a nonsignificant trend towards declining 30-day mortality from 0.44% in 2002 to 0.17% in 2004. As a result of these temporal trends, contemporary studies of 90-day mortality following TKA report rates in the range 0.14% to 0.31% [2, 5, 7, 12]. It appears, therefore, that a more accurate estimate of 90-day mortality is approximately 0.2% or one in 500. Some of the observed mortality in this elderly population is unrelated to surgery. The work of Parry and colleagues [9] illustrates this point. Parry and his team studied the 90-day mortality of patients on the waiting list for TKA, and compared this with mortality in the 90 days following surgery. The odds of mortality doubled postoperatively. Extrapolation would suggest that the current additional risk of 90-day mortality posed by TKA surgery alone (ignoring the risk of mortality due to unrelated causes) is in the region of 0.13% or one death in 750 TKAs, with other causes (RE: Bernstein J. Not the Last Word: Safety Alert: One in 200 Knee Replacement Patients Die Within 90 Days of Surgery. Clin Orthop Relat Res. 2017;475:318–323). The authors certify that they, or any members of their immediate families, have no commercial associations (eg, consultancies, stock ownership, equity interest, patent/ licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR or The Association of Bone and Joint Surgeons. J. R. Berstock MBChB, FRCS, MD (&), M. Whitehouse BSc, MBChB, MSc, PhD, FRCS, PGCert Musculoskeletal Research Unit, Department of Orthopaedics, Avon Orthopaedic Centre, Southmead Hospital, Southmead Road, Westbry-onTrym, Bristol, Avon BS10 5NB, UK e-mail: jberstock@gmail.com Letter to the Editor The Association of Bone and Joint Surgeons1 2017