Aims

Uncemented metal acetabular components show good osseointegration, but material stiffness causes stress shielding and retroacetabular bone loss. Cemented monoblock polyethylene components load more physiologically; however, the cement bone interface can suffer fibrous encapsulation and loosening. It was hypothesized that an uncemented titanium-sintered monoblock polyethylene component may offer the optimum combination of osseointegration and anatomical loading.

Background

Non-invasive hemoglobin measurement was introduced to potentially eliminate blood draws postoperatively. We compared the accuracy and effectiveness of a non-invasive hemoglobin measurement system with a traditional blood draw in patients undergoing total joint arthroplasty.

Introduction

Proximal short stems have gained in popularity for perceived bone preservation but more recently, physiological loading. We report the medium term success of a calcar loading, short stem in a large cohort from a single unit with multiple surgeons.

The ODEP (Orthopaedic Data Evaluation Panel) rating system should offer a surgeon and patient extra information when making a choice on which implant to use. However, in the current economic environment, ratings may also influence implant choice by contracting bodies. Our aim was to determine the performance of commonly used Acetabular and femoral components in our unit and compare these to their published ODEP ratings (or absence of rating).

We analysed all of the following primary THR components (12,792) for revision for any reason, using same date ranges as ODEP where more than 100 implantations had occurred. Hip components: Trinity (3A in 2013), Trilogy (10A* in 2016), Atlas (10A in 2013), Trilogy TMT (10A 2010) Durom (not rated), BHR (10A, 2010), ACCIS (not rated); Femoral components: Taperfit (10A in 2013), Taperloc (10A* in 2016), Metafix (3A in 2013), CPT (10A in 2012), Ecofit (not Rated), ESOP (not rated), Minihip (3A 2013), Durom (not rated), BHR (10A 2010), ACCIS (not rated).

Analysis of Kaplan Meier survival curves was undertaken for all components. The rated components and non-rated components were compared using HR and logrank tests for all time groups when ratings were introduced. No statistical difference was observed in any group except for the Trinity cup which had a 98.2% (1344 cups) survival at 6 years.

Component survival in our unit was better than ODEP suggested failure for A category of not more than 1% per year, for all components.

Whilst we applaud the intention to improve data available for prostheses, the present ODEP system does not distinguish between performances of different implants in our unit. We therefore recommend care when relying upon ODEP ratings to make clinical or contracting decisions.

Background

External fixation for a fracture-dislocation to a joint like the elbow, while maintaining joint mobility is currently done after identifying the center of rotation under X-ray guidance, when applying either a mono-lateral or a circular fixator.

Introduction

Magnetic resonance arthrogram (MRA) is the investigation of choice in young adults with symptoms of femero acetabular impingement. The aim of the study is to assess the accuracy of MRA when correlated with surgical findings on hip arthroscopy.

A total of 22 patients with a tibial avulsion fracture involving the insertion of the posterior cruciate ligament (PCL) with grade II or III posterior laxity were reduced and fixed arthroscopically using routine anterior and double posteromedial portals. A double-strand Ethibond suture was inserted into the joint and wrapped around the PCL from anterior to posterior to secure the ligament above the avulsed bony fragment. Two tibial bone tunnels were created using the PCL reconstruction guide, aiming at the medial and lateral borders of the tibial bed. The ends of the suture were pulled out through the bone tunnels and tied over the tibial cortex between the openings of the tunnels to reduce and secure the bony fragment. Satisfactory reduction of the fracture was checked arthroscopically and radiographically.

The patients were followed-up for a mean of 24.5 months (19 to 28). Bone union occurred six weeks post-operatively. At final follow-up, all patients had a negative posterior drawer test and a full range of movement. KT-1000 arthrometer examination showed that the mean post-operative side-to-side difference improved from 10.9 mm (standard deviation (sd) 0.7) pre-operatively to 1.5 mm (sd 0.6) (p = 0.001). The mean Tegner and the International Knee Documentation Committee scores improved significantly (p = 0.001). The mean Lysholm score at final follow-up was 92.0 (85 to 96).

We conclude that this technique is convenient, reliable and minimally invasive and successfully restores the stability and function of the knee.

Cite this article: Bone Joint J 2015;97-B:1220–5.

Two major challenges in arthroplasty are obesity and antibiotic resistance. This study was performed to characterise the organisms responsible for deep infection following total hip arthroplasty and to determine if obesity affected the microbiology profile.

A retrospective analysis of the national surgical site infection register was made to obtain data regarding deep infection following 10948 primary total hip arthroplasty (THA) from 1998–2013, with a minimum of 2 year follow-up.

Of all the primary THAs performed, there were 108 deep infections (56 patients had a BMI >30 (obese) and 52 patients <30). There were no significant differences between cardio-respiratory disease, smoking and alcohol status, and diabetes between the 2 groups. Over the last 15 years, staphylococcus aureus continues to be the most frequently isolated organism. Infection with multiple organisms was found exclusively in obese patients. Furthermore, in obese patients, there was a linear increase with methicillin resistant staphylococcus aureus (MRSA) infections and streptococcus viridans.

On this basis, we recommend careful selection of antibiotic therapy in obese patients, rather than empirical therapy, which can be especially important if there is no growth in an infected THA. In addition, a preoperative discussion regarding dental prophylaxis against streptococcus viridans may be warranted.

When performing total knee replacement (TKR), surgeons must select a size of tibial component tray that most closely matches the anatomy of the proximal tibia. As implants are available in a limited range of sizes, it may be necessary to slightly under or oversize the component. There are concerns overhang could lead to pain from irritation of soft tissues, and underhang could lead to subsidence and failure.

154 TKRs at 1- or 5-year follow up were reviewed prospectively. Oxford Knee Score (OKS), WOMAC and SF-12 was recorded along with pain scores. Scaled radiographs were reviewed and grouped into perfect sizing (78 TKRs, 50.6%), underhang in isolation (48 TKRs, 31.1%), minor overhang 1–3 mm (10 TKRs, 6.49%) or major overhang >3 mm (18 TKRs, 11.7%).

There was no significant difference in the SF-12 (p=0.356), post-operative OKS (p=0.401) or WOMAC (p=0.466) score. For the OKS, there was no difference for the scores collected at 1 year (p=0.176) or at 5 years (p=0.883).

Pre-operative OKS was well matched between the groups (p=0.152). There was no significant difference in the improvement in OKS from pre-operative scores (p=0.662). There was no significant difference in either the OKS or WOMAC pain scores (p=0.237 and 0.542 respectively).

There was no significant association of medial overhang with?medial knee pain (p=1.000) or lateral overhang with lateral knee pain (p=0.569) when compared to the group of patients with a well sized tibial component.

Our results suggest that tibial component overhang or underhang has no detrimental affect on outcome or pain scores. Surgeons should continue to select the tibial component that most closely fits the rim of the proximal tibia while accepting slight overhang if necessary due to the potential longer-term complications of subsidence and premature failure with an undersized tibial tray.

Knee osteoarthritis is common, disabling and can be effectively treated by total knee arthroplasty (TKA). In North America, consideration has been given to the varying outcomes amongst racial groups. However, scant attention has been paid to the outcomes of surgery in different racial groups found in the United Kingdom (UK). We investigated the results of surgery in one of the principal ethnic minorities in the UK; that of a south Asian population.

We retrospectively analysed our prospectively collected database at the Southern General Hospital, Glasgow. We identified 39 Asian patients who had TKA. They were age and sex matched to a Caucasian group. Mean follow up was 40.3 months.

Mean pre-operative oxford knee scores were poorer than in the Caucasian group (8.5 vs. 14.7, p=0.001.) Post operative oxford knee scores were similarly poorer in the Asian group (29.9 vs. 36.1, p=0.07.) Interestingly, the change in oxford knee scores was similar in both groups.

SF-12 and WOMAC scores demonstrated poorer pre and post operative scores in the Asian group. Knee flexion was greater in the Asian group, however (107.5° vs. 106.2°, p=0.742.)

We conclude that while patients of Asian origin have poorer post operative pain and function following TKA, they have a similar gain from surgery as do a Caucasian group and therefore surgery is effective intervention in this group. An important topic for further work is to identify why Asians present later in their arthritic disease process to healthcare professionals than do their Caucasian counterparts.

Raised blood pressures (BP) are associated with increased cardiovascular risks such as myocardial infarction, stroke and arteriosclerosis. During surgery the haemodynamic effects of stress are closely monitored and stabilised by the anaesthetist. Although there have been many studies assessing the effects of intraoperative stress on the patient, little is known about the impact on the surgeon.

A prospective cohort study was carried out using an ambulatory blood pressure monitor to measure the BP and heart rates (HR) of three consultants and their respective trainees during hallux valgus, hip and knee arthroplasty surgery. Our principle aim was to assess the physiological effects of performing routine operations on the surgeon. We noted if there were any differences in the stress response of the lead surgeon, in comparison to when the same individual was assisting. In addition, we recorded the trainee's BP and HR when they were operating independently.

All of the surgeons had higher BP and HR readings on operating days compared to baseline. When the trainer was leading the operation, their BP gradually increased until implant placement, while their trainees remained stable. On the other hand, when the trainee was operating and the trainer assisting, the trainer's BP peaked at the beginning of the procedure, and slowly declined as it progressed. The trainee's BP remained elevated throughout. The highest peaks for trainees were noted during independent operating.

We conclude that all surgery is stressful, and that trainees are more likely to be killing themselves than their trainers.

Cardiovascular disease is now the leading cause of morbidity and mortality worldwide. Raised blood pressures (BP) are associated with increased cardiovascular risks such as myocardial infarction, stroke and arteriosclerosis. During surgery the haemodynamic effects of stress are closely monitored and stabilised by the anaesthetist. Although there have been many studies assessing the effects of intraoperative stress on the patient, little is known about the impact on the surgeon.

A prospective cohort study was carried out using an ambulatory blood pressure monitor to measure the BP and heart rates (HR) of three consultants and their respective trainees during hallux valgus, hip and knee arthroplasty surgery. Our principle aim was to assess the physiological effects of performing routine operations on the surgeon. We noted if there were any differences in the stress response of the lead surgeon, in comparison to when the same individual was assisting. In addition, we recorded the trainee's BP and HR when they were operating independently. The intraoperative measurements were compared with their baseline readings and their stress response, assessed using the Bruce protocol.

Many trends were noted in this pilot study. All of the surgeons had higher BP and HR readings on operating days compared to baseline. The physiological parameters normalised by one hour post-theatre list in all subjects. When the trainer was leading the operation, their BP gradually increased until implant placement, while their trainees remained stable. On the other hand, when the trainee was operating and the trainer assisting, the trainer's BP peaked at the beginning of the procedure, and slowly declined as it progressed. The trainee's BP remained elevated throughout. The highest peaks for trainees were noted during independent operating.

We conclude that all surgery is stressful, and that trainees are more likely to be killing themselves than their trainers.

Anterior knee pain following primary total knee replacement (TKR) is a common problem with average reported rates in the literature of approximately 10%. Symptoms are frequently attributed to the patellofemoral joint, and the treatment of the patella during total knee replacement is controversial.

There is no article in the literature that the authors know of that has specifically evaluated the effect of patella rim cautery on TKR outcome. This is a denervation technique that has historically been employed, with no evidence base. A prospective comparative cohort study was performed to compare the outcome scores of patients who underwent circumferential patella rim cautery, with those who did not.

Patients who had undergone a primary TKR were identified from the unit's arthroplasty database. Two cohorts, who were age and gender matched, were established. None of the patients had their patella resurfaced, but all had a patellaplasty. The Low Contact Stress TKR (Depuy International) was used in all cases.

The effect of circumferential patella rim cautery on the Oxford Knee Score (OKS) and the more anterior knee pain specific Patellar Score (PS) a minimum of 2 years post surgery was evaluated. Previous reports have suggested that a change of 5 points in the OKS represents a clinical difference. A sample size calculation based on an effect size of 5 points with 80% power and a p-value of 0.05 would require a minimum of 76 patients in each group.

There were 94 patients who had undergone patellaplasty only, and 98 patients who had supplementary circumferential patella rim cautery during their primary TKR. The mean OKS were 34.61 and 33.29 respectively (p=0.41), while the PS scores were 21.03 and 20.87 (p=0.87).

No statistically significant differences were noted between the groups for either outcome score. Patella rim cauterisation is unnecessary in primary TKR.

The ideal acetabular component is characterised by reliable, long-term fixation with physiological loading of bone and a low rate of wear. Trabecular metal is a porous construct of tantalum which promotes bony ingrowth, has a modulus of elasticity similar to that of cancellous bone, and should be an excellent material for fixation.

Between 2004 and 2006, 55 patients were randomised to receive either a cemented polyethylene or a monobloc trabecular metal acetabular component with a polyethylene articular surface. We measured the peri-prosthetic bone density around the acetabular components for up to two years using dual-energy x-ray absorptiometry.

We found evidence that the cemented acetabular component loaded the acetabular bone centromedially whereas the trabecular metal monobloc loaded the lateral rim and behaved like a hemispherical rigid metal component with regard to loading of the acetabular bone. We suspect that this was due to the peripheral titanium rim used for the mechanism of insertion.

Infection following hip arthroplasty although uncommon can have devastating outcomes. Obesity, defined as a BMI of ≥ 30, is a risk factor for infection in this population. Coagulase negative staphylococcus aureus (CNS) is the commonest causative organism isolated from infected arthroplasties. This study was performed to determine if there has been a change in the causative organisms isolated from infected hip arthroplasties and to see if there is a difference in obese patients.

Data on all deep infection following primary and revision hips was obtained from the surgical site infection register from April 1998 to Nov 2007. Case notes were reviewed retrospectively. There were 49 patients with 51 infected arthroplasties; 25 infected Primary THAs and 26 infected Revision THAs. We found a female preponderance in the infected primary and revision THAs (n=30). 63.2% of all patients had a BMI of ≥ 30, compared to only 34.7% of the non infected population (p< 0.0001). Over the period studied, CNS was the most common organism isolated (56.8%) followed by mixed organisms (37.2%) and staphylococcus aureus (25.4%). Multiple organisms were found exclusively in obese patients. In more than half of cases the causative organisms were resistant to more than two antibiotics.

This study shows that over the last 10 years, CNS continues to be the most frequently isolated organism in infected hip arthroplasties. Multiple organisms with multiple antibiotic resistances are common in obese patients. On this basis we recommend that combination antibiotic therapy should be considered in obese patients.

The management of the patella during total knee replacement is controversial. In some studies the absence of patellar resurfacing results in residual anterior knee pain in over 10% of patients. One form of treatment which may be used in an endeavour to reduce this is circumferential patellar rim electrocautery. This is believed to partially denervate the patella. However, there is no evidence of the efficacy of this procedure, nor do we know if it results in harm.

A retrospective comparative cohort study was performed of 192 patients who had undergone a primary total knee replacement with the porous coated Low Contact Stress rotating platform prosthesis without patellar resurfacing between 2003 and 2007. In 98 patients circumferential electrocautery of the patellar rim was performed and in 94 patients it was not. The two groups were matched for gender and age. The general Oxford Knee Score and the more specific patellar score for anterior knee pain were used to assess patient outcomes a minimum of two years post-operatively.

No statistically significant differences were noted between the groups for either scoring system (p = 0.41 and p = 0.87, respectively). Electrocautery of the patella rim did not improve the outcome scores after primary total knee replacement in our patients.

Introduction: The ideal acetabular component has low wear, permanent fixation and physiological bone loading. Recently trabecular metal has been promoted as reproducing the modulus of trabecular bone with a cementless fixation. The aim of this trial was to see if a monobloc trabecular backed polyethylene acetabular component loaded the pelvis physiologically as a cemented polyethylene component.

Method: Between 2004 and 2006 54 patients were ran-domised to a cemented polyethylene acetabular component versus a monobloc trabecular backed polyethylene acetabular component. The primary outcome measurement was bone density in peri-prosthetic acetabular regions of interest measured preoperatively and post operatively at 6 weeks and 1 year. Secondary outcomes measured were radiographic and functional outcomes (HHS and Oxford score).

Results: Radiographically 8 patients in the trabecular group had a significant gap in zone II which resolved in 6 by 1 year. The cemented group had 3 patients with a radiolucent line (zone 1) at 1 year. HHS and OXFORD scores improved with no significant difference between the groups. Both groups had significant loss of bone density in the ilium and ischium. The trabecular group produced a significant increase in bone density in the superolateral region. The cemented group produced increased bone density in the superomedial region.

Discussions and Conclusions: There is a significant reduction in BMD for both groups in the upper pelvis and ischium in keeping with finite element modelling predictions. The press-fit group relative to the cemented group resulted in decreased BMD in the superomedial peri-prosthetic region. The trabecular monobloc cup therefore behaves more like a rigid cementless shell despite the properties of trabecular metal.

Introduction: Infection following hip arthroplasty although uncommon can have devastating outcomes. Obesity, defined as a BMI of ≥ 30, is a known risk factor for infection in this population. Coagulase negative Staph Aureus (CNS) is the commonest causative organism isolated from infected arthroplasties. This study was performed to determine if there has been a change in the causative organisms isolated from infected hip arthroplasties and to see if there is a difference in obese patients.

Methods: Data on all deep infection following primary and revision hips was obtained from the surgical site infection register from April 1998 to November 2007. All case notes were reviewed retrospectively.

Results: There were 49 patients with 51 infected arthroplasties; 25 infected Primary THAs and 26 infected Revision THAs. We found a female preponderance in the infected primary and revision THAs (n=30). 65.3% of all patients had a BMI of ≥ 30. Over the period studied, Coagulase negative Staph was the most common organism isolated (56.8%) followed by mixed organisms (37.2%) and Staph Aureus (25.4%). Multiple organisms were found exclusively in obese patients. In more than half of cases the causative organisms were resistant to ≥ 2 antibiotics.

Discussion: This study shows that over the last 10 years, CNS continues to be the most frequently isolated organism in infected hip arthroplasties. Multiple organisms with multiple antibiotic resistances are common in obese patients. On this basis we recommend that combination antibiotic therapy should be considered in obese patients.

Aim: To determine the epidemiology of total knee replacement in our hospital over two 12 month periods 5 years apart to see if patient BMI and demographics have changed.

Methods: Hospital theatre log books were examined to determine all primary total knee replacements carried out in our hospital during May 2000 – April 2001 and May 2005 – April 2006. Patient notes were examined and the following details were recorded: age, sex and BMI. Data was recorded on an excel spreadsheet.

Results: There was a significant increase in the number of patients undergoing TKR in the 2005 – 2006 time period despite no change in population served (100 vs 228, p< 0.0001). This is also a higher than expected increase in TKR surgery when compared to the national data from the arthroplasty register. There was no significant change in the age of patients undergoing TKR. There was a significant increase in the average BMI of female patients 30.2+\−5.33 vs 32 +\− 6.98 (p=0.03) but no significant difference in the BMI of males. There was also a significant increase in the number of female patients with morbid obesity (BMI> 40) 3\64 vs 19/153 p=0.047.

It would appear that there has been a significant increase in the demand for TKR over a relatively short time period and that there are approximately twice as many women needing TKR than men. Within the females there has been a significant increase in BMI and also a significant increase in those who are morbidly obese undergoing TKR. This data helps predict future demand for both primary and revision arthroplasty services in our hospital.

The humerus is a common site for skeletal metastases in the adult. Surgical stabilisation of such lesions is often necessary to relieve pain and restore function. These procedures are essentially palliative and should therefore provide effective relief from pain for the remainder of the patient’s life without the need for further surgical intervention.

We report a retrospective analysis of 35 patients (37 nails) with symptomatic metastases in the shaft of the humerus which were treated by locked, antegrade nailing. There were 27 true fractures (73.0%) and ten painful deposits (27.0%). Relief from pain was excellent in four (11.4%), good in 29 (82.9%) and fair in two (5.7%) on discharge. Function was improved in all but one patient. One case of palsy of the radial nerve was noted. The mean postoperative survival was 7.1 months (0.2 to 45.5) which emphasises the poor prognosis in this group of patients. There were no failures of fixation and no case in which further surgery was required.

Antegrade intramedullary nailing is an effective means of stabilising the humerus for the palliative treatment of metastases. It relieves pain and restores function to the upper limb with low attendant morbidity.