Splash in elective primary knee and hip replacement: are we adequately protected?

An intra-operative splash is a common occurrence in elective knee and hip replacement surgery and can potentially transmit bloodborne diseases, with devastating consequences. This study aimed to quantify the risk of a splash and to assess its correlation with body mass index, duration of surgery and the volume of lavage fluid used. Between December 2007 and April 2008, 62 consecutive patients (38 women, 24 men) undergoing an elective total knee or total hip replacement (TKR, THR) were recruited into the study (32 TKRs and 30 THRs) after appropriate consent. A splash occurred in all 62 cases. A THR had a slightly higher risk of a splash than a TKR, but this was not statistically significant (p = 0.27). The correlation between body mass index, duration of surgery and the amount of pulse lavage used with a splash was r = 0.013, (non-significant), r = 0.52, (significant) and r = 0.92 (highly significant), respectively. A high number of splashes are generated during a TKR and a THR. The simple visor mask fails to protect the surgeon, the assistant or the patient from the risk of a splash and reverse splash, respectively.

Open simultaneous double dislocation of the metacarpophalangeal and interphalangeal joints of the thumb with ulnar collateral ligament avulsion.

Double dislocations of the thumb at the metacarpophalangeal joint (MCPJ) and interphalangeal joint (IPJ) occurring at the same time are seldom seen in medical practice. The sporadic occurrence of this interesting injury makes it difficult to formulate a clear management protocol. We report an unusual combination of injury involving the right thumb of a 60-year-old man, where the IPJ was dislocated dorsally with a volar dislocation of the MCPJ. It was an open injury with avulsion of the ulnar collateral ligament of the MCPJ. The dislocation was treated successfully by closed reduction in the casualty department, under a ring block. The ulnar collateral ligament was repaired later in the operating theatre. At six months' follow-up, the patient had a full painless range of movement in his thumb with no instability. To our knowledge, this is the first reported case of a thumb double dislocation where the injury was open at both joints. This is also the first case where a volar dislocation of the MCPJ was treated successfully by closed reduction, with an excellent functional outcome.

The Metasul metal-on-metal articulation in primary total hip replacement: clinical and radiological results at ten years.

We report the clinical and radiological outcome at ten years of 104 primary total hip replacements (100 patients) using the Metasul metal-on-metal bearing. Of these, 52 had a cemented Stuehmer-Weber polyethylene acetabular component with a Metasul bearing and 52 had an uncemented Allofit acetabular component with a Metasul liner. A total of 15 patients (16 hips) died before their follow-up at ten years and three were lost to follow-up. The study group therefore comprised 82 patients (85 hips). The mean Oxford score at ten years was 20.7 (12 to 42). Six of 85 hips required revision surgery. One was performed because of infection, one for aseptic loosening of the acetabular component and four because of unexplained pain. Histological examination showed an aseptic lymphocytic vasculitis associated lesion-type tissue response in two of these. Continued follow-up is advocated in order to monitor the long-term performance of the Metasul bearing and tissue responses to metal debris.

Fast-track assessment clinic: selection of patients for a one-stop hip assessment clinic.

INTRODUCTION: The fast-track assessment clinic (FTAC) is a process to select patients who are very likely to require primary total hip replacement. Selected patients can then be seen in a one-off clinic reducing the number of hospital visits, cost to primary care trusts and delay between referral and treatment. PATIENTS AND METHODS: Fifty patients on the waiting list for hip replacement were analysed to see if there were common parameters that led to their inclusion. From these data, fast-track selection criteria (FTSCs) were generated. These FTSCs were used to make a dual comparison of outcomes between 52 patients seen in a traditional clinic. Finally, a pilot study was conducted in which patients fulfilling FTSCs were seen in a designated clinic. RESULTS: An Oxford hip score (OHS) of 34 and above combined with severe loss of joint space, severe marginal osteophytes, or both was common to most patients on the waiting list (84%). FTSCs correctly predicted the outcome of the orthopaedic clinic in 38 patients out of a total of 52. During the pilot stage, positive FTSCs were shown to have a positive predictive value of 92% for joint replacement being carried out and a negative predictive value of 46%. CONCLUSIONS: An OHS of 34 or above combined with complete loss of joint space and/or severe marginal osteophyte formation can be used to select patients who are very likely to need total hip replacement. These patients can be seen in a clinic that combines assessment of surgical indication with medical fitness for surgery.

Birmingham hip resurfacing: is acetabular bone conserved?

Hip resurfacing is a bone-conserving procedure with respect to proximal femoral resection, but there is debate in the literature as to whether the same holds true for the acetabulum. We have investigated whether the Birmingham hip resurfacing conserves acetabular bone. Between 1998 and 2005, 500 Birmingham hip resurfacings were performed by two surgeons. Between 1996 and 2005 they undertook 700 primary hip replacements, with an uncemented acetabular component. These patients formed the clinical material to compare acetabular component sizing. The Birmingham hip resurfacing group comprised 350 hips in men and 150 hips in women. The uncemented total hip replacement group comprised 236 hips in men and 464 hips in women. Age- and gender-matched analysis of a cohort of patients for the sizes of the acetabular components required for the two types of replacement was also undertaken. Additionally, an analysis of the sizes of the components used by each surgeon was performed. For age-matched women, the mean outside diameter of the Birmingham hip resurfacing acetabular components was 2.03 mm less than that of the acetabular components in the uncemented total hip replacements (p < 0.0001). In similarly matched men there was no significant difference (p = 0.77). A significant difference was also found between the size of acetabular components used by the two surgeons for Birmingham hip resurfacing for both men (p = 0.0015) and women (p = 0.001). In contrast, no significant difference was found between the size of acetabular components used by the two surgeons for uncemented total hip replacement in either men or women (p = 0.06 and p = 0.14, respectively). This suggests that variations in acetabular preparation also influence acetabular component size in hip resurfacing.

The relationship between obesity and the age at which hip and knee replacement is undertaken.

We audited the relationship between obesity and the age at which hip and knee replacement was undertaken at our centre. The database was analysed for age, the Oxford hip or knee score and the body mass index (BMI) at the time of surgery. In total, 1369 patients were studied, 1025 treated by hip replacement and 344 by knee replacement. The patients were divided into five groups based on their BMI (normal, overweight, moderately obese, severely obese and morbidly obese). The difference in the mean Oxford score at surgery was not statistically significant between the groups (p > 0.05). For those undergoing hip replacement, the mean age of the morbidly obese patients was ten years less than that of those with a normal BMI. For those treated by knee replacement, the difference was 13 years. The age at surgery fell significantly for those with a BMI > 35 kg/m(2) for both hip and knee replacement (p > 0.05). This association was stronger for patients treated by knee than by hip replacement.

Assessment of player performance following return to sport after hamstring muscle strain injury.

OBJECTIVE: To determine if there is any decrease in playing performance of athletes following return to sport after recovery from hamstring muscle strain injury. DESIGN: Prospective cohort study. PARTICIPANTS: One professional Australian football team over two playing seasons. METHODS: For every game, the team coach rated player performance proportional to time spent on the ground playing (an integer score out of a maximum of 10). Player performance ratings were compared pre- and post-hamstring muscle strain injury to assess player performance upon return to sport. RESULTS: Thirteen athletes had hamstring injuries and the required player ratings were available. The mean player performance rating for the entire playing season in which the player was injured was 6.9. The mean player performance rating for the two games prior to injury was 6.8 as opposed to 5.4 for the two games after return to sport. Athletes had a significantly lower player performance rating immediately upon return to sport when compared to ratings for the entire season (p<0.001) and when compared to ratings from the two games prior to injury (p<0.001). CONCLUSIONS: Following return to sport from hamstring injury, player performance as assessed by the team coach is reduced. This suggests that some athletes may return to sport prior to complete resolution of the injury.

Are systemic emboli reduced in computer-assisted knee surgery?: A prospective, randomised, clinical trial.

We undertook a prospective, randomised study using a non-invasive transcranial Doppler device to evaluate cranial embolisation in computer-assisted navigated total knee arthroplasty (n = 14) and compared this with a standard conventional surgical technique using intramedullary alignment guides (n = 10). All patients were selected randomly without the knowledge of the patient, anaesthetists (before the onset of the procedure) and ward staff. The operations were performed by a single surgeon at one hospital using a uniform surgical approach, instrumentation, technique and release sequence. The only variable in the two groups of patients was the use of single tracker pins of the imageless navigation system in the tibia and femur of the navigated group and intramedullary femoral and tibial alignment jigs in the non-navigated group. Acetabular Doppler signals were obtained in 14 patients in the computer-assisted group and nine (90%) in the conventional group, in whom high-intensity signals were detected in seven computer-assisted patients (50%) and in all of the non-navigated patients. In the computer-assisted group no patient had more than two detectable emboli, with a mean of 0.64 (SD 0.74). In the non-navigated group the number of emboli ranged from one to 43 and six patients had more than two detectable emboli, with a mean of 10.7 (sd 13.5). The difference between the two groups was highly significant using the Wilcoxon non-parametric test (p = 0.0003).Our findings show that computer-assisted total knee arthroplasty, when compared with conventional jig-based surgery, significantly reduces systemic emboli as detected by transcranial Doppler ultrasonography.

Limb alignment in computer-assisted minimally-invasive unicompartmental knee replacement.

Twenty patients underwent simultaneous bilateral medial unicompartmental knee arthroplasty. Pre-operative hip-knee-ankle alignment and valgus stress radiographs were used to plan the desired post-operative alignment of the limb in accordance with established principles for unicompartmental arthroplasty. In each patient the planned alignment was the same for both knees. Overall, the mean planned post-operative alignment was to 2.3 degrees of varus (0 degrees to 5 degrees ). The side and starting order of surgery were randomised, using conventional instrumentation for one knee and computer-assisted surgery for the opposite side. The mean variation between the pre-operative plan and the achieved correction in the navigated and the non-navigated limb was 0.9 degrees (sd 1.1; 0 degrees to 4 degrees ) and 2.8 degrees (sd 1.4; 1 degrees to 7 degrees ), respectively. Using the Wilcoxon signed rank test, we found the difference in variation statistically significant (p < 0.001). Assessment of lower limb alignment in the non-navigated group revealed that 12 (60%) were within +/- 2 degrees of the pre-operative plan, compared to 17 (87%) of the navigated cases.Computer-assisted surgery significantly improves the post-operative alignment of medial unicompartmental knee arthroplasty compared to conventional techniques in patients undergoing bilateral simultaneous arthroplasty. Improved alignment after arthroplasty is associated with better function and increased longevity.

The distribution of cement penetration into bovine acetabular bone utilising various pressurisation techniques.

Most mechanical failures of acetabular fixation within ten years of primary cemented hip replacement are attributable to a failure to achieve good initial fixation of bone and cement. Several studies have suggested that to achieve good fixation between bone and cement between 3 mm and 5 mm of cement penetration into bone is desirable. Whilst several acetabular cement pressurisation systems exist, little is known about the effects of cement pressurisation on the pattern of penetration of cement into cancellous bone within the pelvis. The current paper assesses the penetration of bone cement into bovine acetabular bone by various pressurisation techniques. We found that pressurisation with the use of a swab in glove or the DePuy pressuriser led to improvement in cement penetration both in terms of maximum depth and also percentage cover of the cup by cement (p<0.05). There was no significant difference in mean maximal penetration between the use of the pressuriser and the swab in a glove technique (p=0.3). If only a plain cup was used as a pressuriser, the penetration achieved was significantly lower in comparison to use of a pressuriser (p<0.02). When compared to previously documented acrylic models, the pattern of intrusion noted in the bovine model was different: penetration was lower at the equatorial and base regions of the acetabulum.

Blood loss after total knee replacement: effects of computer-assisted surgery.

We carried out a prospective randomised study to evaluate the blood loss in 60 patients having a total knee arthroplasty and divided randomly into two equal groups, one having a computer-assisted procedure and the other a standard operation. The surgery was carried out by a single surgeon at one institution using a uniform approach. The only variable in the groups was the use of intramedullary femoral and tibial alignment jigs in the standard group and single tracker pins of the imageless navigation system in the tibia and femur in the navigated group. The mean drainage of blood was 1351 ml (715 to 2890; 95% confidence interval (CI) 1183 to 1518) in the computer-aided group and 1747 ml (1100 to 3030; CI 1581 to 1912) in the conventional group. This difference was statistically significant (p = 0.001). The mean calculated loss of haemoglobin was 36 g/dl in the navigated group versus 53 g/dl in the conventional group; this was significant at p < 0.00001. There was a highly significant reduction in blood drainage and the calculated Hb loss between the computer-assisted and the conventional techniques. This allows the ordering of less blood before the operation, reduces risks at transfusion and gives financial saving. Computer-assisted surgery may also be useful for patients in whom blood products are not acceptable.

The effect of femoral stem size on failure rates in total hip replacement cemented with Boneloc.

We report the clinical and radiological outcome of 111 primary Taperloc hip arthroplasties implanted with Boneloc bone cement and the effect of stem size on survival. The mean follow-up was 5.3 years (range 3.2-6.6 years). The average age of the patients at operation was 73.4 years. Twenty-seven were male and 84 female. We defined clinical failures as those who had revision for aseptic loosening, or those symptomatic with pain and subsequent confirmation of radiographic loosening. The overall failure rate noted for this type of stem was 20.7%. Failure occurred on average at 3.3 years (0.3-6.3 years). However, when the data is broken down to different sizes of stem, the patients who had smaller Taperloc stems (7.5 mm or 10 mm) had a 27% failure rate whereas stems equal to, or greater than, 12.5 mm had a 12% failure rate over the same period (p < 0.05). As compared to other types of femoral stems used with Boneloc cement, the Taperloc stems survive better. Furthermore, larger stems survive even better. We suggest that these larger stems behave more like uncemented femoral stems. The finish on the stem is not a major contributor as has been suggested in the past.