Performance and learning curve of a surgical care practitioner in completing hip aspirations.

INTRODUCTION The roles of non-medically trained practitioners within the NHS are expanding; they are now being employed by many specialties, including surgery, to relieve pressures on healthcare teams. AIMS To investigate the learning curve and competence of an orthopaedic surgical care practitioner (SCP) in performing hip aspirations. METHODS Data were retrospectively collected on 510 orthopaedic hip aspirations, of which 360 were completed by a single SCP and 150 were completed by surgeons before the SCP took over routine aspiration. The 360 aspirations completed by an SCP were separated into groups of 30 by date, so any trend in failure rate could be analysed. Ordinal χ2 analysis was used to analyse this trend and Pearson χ2 analysis was used to analyse differences in failure rates between professionals. RESULTS The hip aspiration failure rate for the SCP was significantly lower than for the surgeons; 8.6% vs 20.7% (P<0.001). With the experience gained in completing the first 210 procedures, the failure rate of the SCP dropped to 3.3% for the remaining 150 procedures. This downward trend in hip aspiration failure rate, with advancing experience of the SCP, was shown to be statistically significant (P=0.006). DISCUSSION SCPs who complete hip aspirations on a regular basis have significantly lower failure rates than surgeons, probably as a result of the learning curve, which this study demonstrated. Other trusts should consider delegating routine hip aspiration work to a designated SCP to lower failure rates.

Surface finish of the Exeter Trauma Stem: a cause for concern?

Recent guidance recommends the use of a well-proven cemented femoral stem for hemiarthroplasty in the management of fractures of the femoral neck, and the Exeter Trauma Stem (ETS) has been suggested as an example of such an implant. The design of this stem was based on the well-proven Exeter Total Hip Replacement stem (ETHRS). This study assessed the surface finish of the ETS in comparison with the ETHRS. Two ETSs and two ETHRSs were examined using a profilometer with a precision of 1 nm and compared with an explanted Exeter Matt stem. The mean roughness average (RA) of the ETSs was approximately ten times higher than that of the ETHRSs (0.235 µm (0.095 to 0.452) versus 0.025 µm (0.011 to 0.059); p < 0.001). The historical Exeter Matt stem roughness measured a mean RA of 0.973 µm (0.658 to 1.159). The change of the polished Exeter stem to a matt surface finish in 1976 resulted in a high stem failure rate. We do not yet know whether the surface differences between ETS and ETHRS will be clinically significant. We propose the inclusion of hemiarthroplasty stems in national joint registries.

Forced-air warming and ultra-clean ventilation do not mix: an investigation of theatre ventilation, patient warming and joint replacement infection in orthopaedics.

We investigated the capacity of patient warming devices to disrupt the ultra-clean airflow system. We compared the effects of two patient warming technologies, forced-air and conductive fabric, on operating theatre ventilation during simulated hip replacement and lumbar spinal procedures using a mannequin as a patient. Infection data were reviewed to determine whether joint infection rates were associated with the type of patient warming device that was used. Neutral-buoyancy detergent bubbles were released adjacent to the mannequin's head and at floor level to assess the movement of non-sterile air into the clean airflow over the surgical site. During simulated hip replacement, bubble counts over the surgical site were greater for forced-air than for conductive fabric warming when the anaesthesia/surgery drape was laid down (p = 0.010) and at half-height (p < 0.001). For lumbar surgery, forced-air warming generated convection currents that mobilised floor air into the surgical site area. Conductive fabric warming had no such effect. A significant increase in deep joint infection, as demonstrated by an elevated infection odds ratio (3.8, p = 0.024), was identified during a period when forced-air warming was used compared to a period when conductive fabric warming was used. Air-free warming is, therefore, recommended over forced-air warming for orthopaedic procedures.

Hip resurfacing revision rates: radiological audit of risk factors.

INTRODUCTION: We performed a retrospective radiological audit of the hip resurfacings carried out in our trust over a five-year period. Abnormal cup inclination angle (CIA) and stem shaft angle (SSA) are recognised risk factors for revision in hip resurfacing. Our aims were to identify the CIA and SSA for hip resurfacings in our trust, to determine the revision rate in a CIA of ≥60° and an SSA of >0° varus, thereby identifying a high risk group for close, long-term follow up. METHODS: A total of 247 patients underwent hip resurfacing in our trust between April 2003 and March 2008. The CIA and SSA were recorded. Of the 247 patients, 26 were excluded as there were no appropriate radiographs and so results were analysed for 221 patients. RESULTS: The mean CIA was 47.6°. Over a third of the patients (34%) had a CIA of >50° and 13% had >60°. The mean SSA was 1.4° varus. Over two-thirds of the patients (67%) had a varus SSA. There were six revisions but one was excluded as it was secondary to infection. The revision rate was 10% in patients with a CIA of ≥60° and 1% in those with a CIA of <60° (p=0.017), and 1% in a varus and 4% in a valgus SSA ((p)>0.05) respectively. CONCLUSIONS: The measurement of the CIA and SSA in hip resurfacings has identified a high risk group for close long-term follow up. There is already a 10% revision rate in those patients with a CIA of >60°. Hip resurfacing may generate a large revision burden in the 'average' surgeon's hands and all hospitals/surgeons should review their radiological outcomes critically and identify those at risk of revision.

Lower rates of dislocation with increased femoral head size after primary total hip replacement: a five-year analysis of NHS patients in England.

Increased femoral head size may reduce dislocation rates following total hip replacement. The National Joint Registry for England and Wales has highlighted a statistically significant increase in the use of femoral heads ≥ 36 mm in diameter from 5% in 2005 to 26% in 2009, together with an increase in the use of the posterior approach. The aim of this study was to determine whether rates of dislocation have fallen over the same period. National data for England for 247 546 procedures were analysed in order to determine trends in the rate of dislocation at three, six, 12 and 18 months after operation during this time. The 18-month revision rates were also examined. Between 2005 and 2009 there were significant decreases in cumulative dislocations at three months (1.12% to 0.86%), six months (1.25% to 0.96%) and 12 months (1.42% to 1.11%) (all p < 0.001), and at 18 months (1.56% to 1.31%) for the period 2005 to 2008 (p < 0.001). The 18-month revision rates did not significantly change during the study period (1.26% to 1.39%, odds ratio 1.10 (95% confidence interval 0.98 to 1.24), p = 0.118). There was no evidence of changes in the coding of dislocations during this time. These data have revealed a significant reduction in dislocations associated with the use of large femoral head sizes, with no change in the 18-month revision rate.

Return to theatre following total hip and knee replacement, before and after the introduction of rivaroxaban: a retrospective cohort study.

Rivaroxaban has been recommended for routine use as a thromboprophylactic agent in patients undergoing lower-limb arthroplasty. However, trials supporting its use have not fully evaluated the risks of wound complications. This study of 1048 total hip/knee replacements records the rates of return to theatre and infection before and after the change from a low molecular weight heparin (tinzaparin) to rivaroxaban as the agent of chemical thromboprophylaxis in patients undergoing lower-limb arthroplasty. During a period of 13 months, 489 consecutive patients undergoing lower-limb arthroplasty received tinzaparin and the next 559 consecutive patients received rivaroxaban as thromboprophylaxis. Nine patients in the control (tinzaparin) group (1.8%, 95% confidence interval 0.9 to 3.5) returned to theatre with wound complications within 30 days, compared with 22 patients in the rivaroxaban group (3.94%, 95% confidence interval 2.6 to 5.9). This increase was statistically significant (p = 0.046). The proportion of patients who returned to theatre and became infected remained similar (p = 0.10). Our study demonstrates the need for further randomised controlled clinical trials to be conducted to assess the safety and efficacy of rivaroxaban in clinical practice, focusing on the surgical complications as well as the potential prevention of venous thromboembolism.

Unsuitability and high perforation rate of latex-free gloves in arthroplasty: a cause for concern.

INTRODUCTION: Any increase in perforations in surgical gloves is a concern. We conducted a prospective study to find a clinically acceptable brand of latex-free gloves suitable for orthopaedic surgery. METHOD: Five different brands of gloves approved for use were selected. Two of the latex-free gloves were rejected as their clinical usability in arthroplasty was poor. The Cardinal Esteem latex-free glove has a smooth surface and was slippery, especially in total knee arthroplasty. The Biogel Skin Sense under glove was found to be unacceptably thick, affecting both surgical dexterity and tactility. RESULTS: The three remaining gloves were Biogel latex (control), Synthesis Polyco (latex-free) and Cardinal Esteem SMT (latex-free). Gloves were then collected for testing from 241 arthroplasties. Gloves used for primary knee/hip replacements were tested using a validated water distension test. Latex-free gloves were found to have higher perforation rates compared to latex. CONCLUSION: Our study demonstrates that currently available latex-free gloves have inferior clinical performance and are not recommended for use in arthroplasty surgery.

Wound complications in elective orthopaedics: are current British national data relevant?

INTRODUCTION: The UK Nosocomial Infection National Surveillance Service (NINSS) collects data on surgical wound infection in a variety of procedures, including arthroplasty, to allow comparison between institutions. PATIENTS AND METHODS: We have compared the results of a 6-month data collection by NINSS within our department with our own grading system of wound complications in elective arthroplasty surgery. RESULTS: In this period, NINSS has reported one wound infection in our patients. However, we have recorded five patients who were returned to theatre for wound debridement, and yielded positive cultures from multiple specimens. Seven patients received antibiotic therapy alone for wound problems. CONCLUSIONS: We present our wound grading system as suitable for the collection of data on wound complications in elective orthopaedic surgery.

Wear analysis of failed acetabular polyethylene: a comparison of analytical methods.

There are many methods for analysing wear volume in failed polyethylene acetabular components. We compared a radiological technique with three recognised ex vivo methods of measurement. We tested 18 ultra-high-molecular-weight polyethylene acetabular components revised for wear and aseptic loosening, of which 13 had pre-revision radiographs, from which the wear volume was calculated based upon the linear wear. We used a shadowgraph technique on silicone casts of all of the retrievals and a coordinate measuring method on the components directly. For these techniques, the wear vector was calculated for each component and the wear volume extrapolated using mathematical equations. The volumetric wear was also measured directly using a fluid-displacement method. The results of each technique were compared. The series had high wear volumes (mean 1385 mm(3); 730 to 1850) and high wear rates (mean 205 mm(3)/year; 92 to 363). There were wide variations in the measurements of wear volume between the radiological and the other techniques. Radiograph-derived wear volume correlated poorly with that of the fluid-displacement method, co-ordinate measuring method and shadowgraph methods, becoming less accurate as the wear increased. The mean overestimation in radiological wear volume was 47.7% of the fluid-displacement method wear volume. Fluid-displacement method, coordinate measuring method and shadowgraph determinations of wear volume were all better than that of the radiograph-derived linear measurements since they took into account the direction of wear. However, only radiological techniques can be used in vivo and remain useful for monitoring linear wear in the clinical setting. Interpretation of radiological measurements of acetabular wear must be done judiciously in the clinical setting. In vitro laboratory techniques, in particular the fluid-displacement method, remain the most accurate and reliable methods of assessing the wear of acetabular polyethylene.

Pre-heating of components in cemented total hip arthroplasty.

Fatigue fractures which originate at stress-concentrating voids located at the implant-cement interface are a potential cause of septic loosening of cemented femoral components. Heating of the component to 44 degrees C is known to reduce the porosity of the cement-prosthesis interface. The temperature of the cement-bone interface was recorded intra-operatively as 32.3 degrees C. A simulated femoral model was devised to study the effect of heating of the component on the implant-cement interface. Heating of the implant and vacuum mixing have a synergistic effect on the porosity of the implant-cement interface, and heating also reverses the gradients of microhardness in the mantle. Heating of the implant also reduces porosity at the interface depending on the temperature. A minimum difference in temperature between the implant and the bone of 3 degrees C was required to produce this effect. The optimal difference was 7 degrees C, representing a balance between maximal reduction of porosity and an increased risk of thermal injury. Using contemporary cementing techniques, heating the implant to 40 degrees C is recommended to produce an optimum effect.

Premature wear and osteolysis in an HA-coated, uncemented total hip arthroplasty.

The ABG I cementless hip prosthesis has demonstrated unacceptably high rates of wear and osteolysis in our patients. We performed a retrospective study of 97 hips implanted between 1992 and 1998. Radiographic analysis revealed high rates of wear of the polyethylene liner with marked peri-acetabular osteolysis. Clinical examination indicated that many of these patients were initially asymptomatic. Wear-related problems have required ten hips to be revised and a furher 13 are awaiting revision. This gives a failure rate of 24% at a mean follow-up of 69 months. Contributing factors are likely to include poor wear characteristics of the polyethylene liners which were gamma irradiated in air, and increased wear debris caused by a poor fit of the polyethylene liner within the shell. We believe that all ABG I implants should be immediately reviewed and remain under careful, long-term follow-up.

Extramedullary or intramedullary tibial alignment guides: a randomised, prospective trial of radiological alignment.

We undertook a prospective, randomised study of 135 total knee arthroplasties to determine the most accurate and reliable technique for alignment of the tibial prosthesis. Tibial resection was guided by either intramedullary or extramedullary alignment jigs. Of the 135 knees, standardised postoperative radiographs suitable for assessment were available in 100. Correct tibial alignment was found in 85% of the intramedullary group compared with 65% of the extramedullary group (p = 0.019). We conclude that intramedullary guides are superior to extramedullary instruments for alignment of the tibial prosthesis.

Joint line restoration after revision total knee arthroplasty.

In 99 patients, 107 knee replacements were revised in two centers by two surgeons using a single revision total knee arthroplasty system. A retrospective radiographic review of joint line position before and after revision total knee arthroplasty was made, and compared with the joint line position before primary knee arthroplasty. Prospectively collected Knee Society Clinical Rating Scores were correlated with radiographic findings. The joint line position in unreplaced knee replacements averaged 16 mm, and the joint line position in knee replacements before revision surgery averaged 17 mm. The joint line was elevated by the revision total knee arthroplasty in 85 of 107 knees (79%). After the revision total knee replacement, the joint line elevation averaged 24 mm. The Knee Society Clinical Rating Score after revision surgery averaged 131 points. If the joint line position was elevated more than 8 mm, the Knee Society Clinical Rating Score averaged 125 points, if the joint line was elevated less than 8 mm, the score averaged 141 points. Joint line elevation after revision total knee replacement is a problem. Excessive elevation may result in worse clinical outcomes. Distal femoral augments should be used more often and with greater thicknesses. Standard implants used for revision surgery should have increased distal dimensions.

Diagnostic injection around the shoulder: hit and miss? A cadaveric study of injection accuracy.

In a cadaver study the success of injections in the subacromial space and acromioclavicular joint was studied. Twenty-four shoulders were dissected after separate dye injection was performed with the patient in the supine position. Subacromial bursa injection was successful in 83% (20 shoulders), but in 15 shoulders other structures were also infiltrated, including seven injections in the rotator cuff. Acromioclavicular joint injection was successful in 67% (16 shoulders), but half involved other structures. The authors believe that misplaced injections may be diagnostically misleading and potentially harmful.

Twenty-three years of experience with sphincterotomy and sphincteroplasty for stenosis of the sphincter of Oddi.

A 23 year experience with papillotomy, sphincterotomy and sphincteroplasty for stenosis of the sphincter of Oddi shows sphincteroplasty to be the best procedure, with 79% of the patients obtaining a good result. The procedure was done for a demonstrable organic change in the sphincter, often associated with acute cholecystitis in older patients, the postcholecystectomy syndrome in those in whom a long cystic stump had been left at the first operation or in patients with chronic recurring pancreatitis. The study included 138 private patients observed from two months to 22 years. There were four postoperative deaths, an operative mortality of 2.9%, as two patients had been operated upon twice. The poor results were associated with recurring attacks of pancreatitis not cured by the procedure or developing subsequent to it, probably being attributable to persistent obstruction of the terminal part of the pancreatic duct. The results suggest that sphincteroplasty, if performed on suitably selected patients, is a safe procedure which should give good results in more than 75% of the patients.