Aims

Our aim was to examine the clinical and radiographic outcomes in 257 consecutive Oxford unicompartmental knee arthroplasties (OUKAs) (238 patients), five years post-operatively.

Ceramic-on-metal (CoM) is a relatively new bearing combination for total hip arthroplasty (THA) with few reported outcomes. A total of 287 CoM THAs were carried out in 271 patients (mean age 55.6 years (20 to 77), 150 THAs in female patients, 137 in male) under the care of a single surgeon between October 2007 and October 2009. With the issues surrounding metal-on-metal bearings the decision was taken to review these patients between March and November 2011, at a mean follow-up of 34 months (23 to 45) and to record pain, outcome scores, radiological analysis and blood ion levels. The mean Oxford Hip Score was 19.2 (12 to 53), 254 patients with 268 hips (95%) had mild/very mild/no pain, the mean angle of inclination of the acetabular component was 44.8^o (28^o to 63^o), 82 stems (29%) had evidence of radiolucent lines of > 1 mm in at least one Gruen zone and the median levels of cobalt and chromium ions in the blood were 0.83 μg/L (0.24 μg/L to 27.56 μg/L) and 0.78 μg/L (0.21 μg/L to 8.84 μg/L), respectively. The five-year survival rate is 96.9% (95% confidence interval 94.7% to 99%).

Due to the presence of radiolucent lines and the higher than expected levels of metal ions in the blood, we would not recommend the use of CoM THA without further long-term follow-up. We plan to monitor all these patients regularly.

Cite this article: Bone Joint J 2015;97-B:300–5.

In an initial randomised controlled trial (RCT) we segregated 180 patients to one of two knee positions following total knee replacement (TKR): six hours of knee flexion using either a jig or knee extension. Outcome measures included post-operative blood loss, fall in haemoglobin, blood transfusion requirements, knee range of movement, limb swelling and functional scores. A second RCT consisted of 420 TKR patients randomised to one of three post-operative knee positions: flexion for three or six hours post-operatively, or knee extension.

Positioning of the knee in flexion for six hours immediately after surgery significantly reduced blood loss (p = 0.002). There were no significant differences in post-operative range of movement, swelling, pain or outcome scores between the various knee positions in either study. Post-operative knee flexion may offer a simple and cost-effective way to reduce blood loss and transfusion requirements following TKR.

We also report a cautionary note regarding the potential risks of prolonged knee flexion for more than six hours observed during clinical practice in the intervening period between the two trials, with 14 of 289 patients (4.7%) reporting lower limb sensory neuropathy at their three-month review.

Cite this article: Bone Joint J 2014;96-B:201–9.

With greater numbers of younger patients undergoing total hip replacement (THR), the effect of patient age on the diameter of the femoral canal may become more relevant. This study aimed to investigate the relationship between the diameter of the diaphysis of the femoral canal with increasing age in a large number of patients who underwent THR. A total of 1685 patients scheduled for THR had their femoral dimensions recorded from calibrated radiographs. There were 736 males and 949 females with mean ages of 67.1 years (34 to 92) and 70.2 years (29 to 92), respectively. The mean diameter of the femoral canal was 13.3 mm (8.0 to 23.0) for males and 12.7 mm (6.0 to 26.0) for females. There was a poor correlation between age and the diameter of the canal in males (r = 0.071, p = 0.05) but a stronger correlation in females (r = 0.31, p < 0.001).

The diameter of the femoral canal diameter of a female patient undergoing THR could be predicted to increase by 3.2 mm between the ages of 40 and 80 years, in contrast a male would be expected to experience only a 0.6 mm increase during the same period. This increase in the diameter of the canal with age might affect the long-term survival of the femoral component in female patients.

Cite this article: Bone Joint J 2013;95-B:339–42.

The Cementless Oxford Unicompartmental Knee Replacement (OUKR) was developed to address problems related to cementation, and has been demonstrated in a randomised study to have similar clinical outcomes with fewer radiolucencies than observed with the cemented device. However, before its widespread use it is necessary to clarify contraindications and assess the complications. This requires a larger study than any previously published.

We present a prospective multicentre series of 1000 cementless OUKRs in 881 patients at a minimum follow-up of one year. All patients had radiological assessment aligned to the bone–implant interfaces and clinical scores. Analysis was performed at a mean of 38.2 months (19 to 88) following surgery. A total of 17 patients died (comprising 19 knees (1.9%)), none as a result of surgery; there were no tibial or femoral loosenings. A total of 19 knees (1.9%) had significant implant-related complications or required revision. Implant survival at six years was 97.2%, and there was a partial radiolucency at the bone–implant interface in 72 knees (8.9%), with no complete radiolucencies. There was no significant increase in complication rate compared with cemented fixation (p = 0.87), and no specific contraindications to cementless fixation were identified.

Cementless OUKR appears to be safe and reproducible in patients with end-stage anteromedial osteoarthritis of the knee, with radiological evidence of improved fixation compared with previous reports using cemented fixation.

Cite this article: Bone Joint J 2013;95-B:181–7.

Antibiotic prophylaxis aims to reduce wound and prosthetic infection, with minimal adverse effects. The 3 dose Cefuroxime regime is widely used, despite the risk of infective diarrhoea. We describe the results of single dose intraoperative Gentamicin and Amoxicillin compared to this standard regime.

We retrospectively reviewed 220 patients following hip hemiarthroplasty, creating 2 demographically matched cohorts; Group 1: 3 doses of Cefuroxime (n=113) and Group 2: single dose Gentamicin and Amoxicillin (n=107). End points were evidence of infection, length of stay and Clostridium difficile (CD) rates. results showed a significant reduction in group 2 for average length of stay (17 Vs. 13 days p=0.0432) and CD rates (7/113 Vs 0/107 p=0.0158).

Considering antibiotic therapies administered; significant reductions in group 2 for the number of patients that required post-operative antibiotics (99/113 Vs 73/107 p=0.0005), the median antibiotic DDDs (Defined Daily Doses) in 1st 2 post-operative days (0.25 Vs 0 p=0.0000) and those that received Ciprofloxacin or Cefuroxime post-operatively (82/113 Vs 24/107 p=0.0000). No significant difference was found for median antibiotic DDDs, median antibiotic DDDs from 2nd post-operative day, patients that received Flucloxacillin post-operatively.

Measured microbiological outcomes showed a significant reduction in the number of patients with confirmed growth requiring treatment with antibiotics in group 2 (21/23 Vs 12/22 p=0.0053). No difference was found between number patients with operation site swabbed and those with confirmed microbial growth.

We demonstrate single dose Gentamicin and Amoxicillin significantly reduces length of stay, CD rates and the number of patients requiring post-operative antibiotics for wound infection, inferring a reduction in the rate of wound infection. We would recommend this as an effective alternative to the 3 dose Cefuroxime regime.

Aim: To develop a flexion jig that would reliably hold the post-op knee in fixed flexion for a defined time period and determine its influence on peri-operative blood loss, transfusion, pain, and complications (specifically nerve palsy)following TKA.

Methods/Results: A previous study in this department showed immediate postoperative flexion to significantly reduce blood loss following TKR. Following this study, time in flexion was increased to 12 hours in an attempt to further reduce blood loss., some patients then developed a painful lower limb nerve palsy. This palsy was caused by pressure from the jig in the popliteal fossa/calf on nerves. The design of the jig was altered to remove pressure from these areas. Because of this design change, we were unsure whether the new jig would have the same blood saving effect, necessitating a new study.

This prospective randomised controlled trial recruited 420 patients into 3 equal groups: extension, 3 & 6 hrs flexion.

This trial found a significant reduction in blood loss(12%, p=0.006) and length of stay(1/2 day, p=0.006) in the 6 hour flexion group, compared the extension group.

There was no significant difference in pain or complication rates (excluding nerve palsy).

2 patients in the 6 hour group had postoperative nerve palsy, however, this palsy was sensory only and markedly different to that found previously. Although the palsy rate in this study is similar(1.4%) to quoted literature rates (1.3%) for TKA, it is difficult to know if the jig was the cause of palsy as the there was a difference between those caused by the old metal jig (painful) and those in this study (sensory loss only).

Conclusion: The results of this study show post-op flexion for 6 hours to significantly reduce perioperative blood loss. Palsy was reduced to match rates as quoted in the literature.

Purpose: To study the judicious use of re-infusion drains in knee replacement on a target population with strict inclusion criteria and its impact on the transfusion rate and cost savings.

Method: We devised an inclusion criterion after a preliminary study on 200 knee replacements and identified the target population likely to need transfusion after the index procedure. All bilateral total knee replacements, revision total knee replacements and primary total knee replacements were the pre-operative haemoglobin was less then 5 gm/l above the patient’s transfusion trigger were included. These criteria were further validated by retrospective application.

56 patients fulfilled the criteria and 50 patients were included in the study between September 2006 – May 2007. Male/female ratio was 18: 32. Mean age was 66.2 years. Procedure included 33 total knees, 13 bilateral and 4 revision knee replacements.

Results: The overall transfusion rates dropped to 3% (bilateral, revisions 12%) during the period of this study. Mean volume re-infused was 600 ml (0–2600). Average drop in haemoglobin was 2.9 g/dl. No adverse incidents were reported.

Prior to our study the expenditure on allogenic blood transfusion was £13,230. The estimated cost of using the re-infusion system was £6230

A saving of £ 7500 was achieved as a result of using the drain in the “at risk” patient.

Conclusion: Post-operative autologous transfusion is a safe and efficient way to reduce patient’s exposure to donor blood. Use of re-infusion drains directed at a target population reduces need for allogenic blood and is cost effective.

Hip fractures are a major challenge and impose high demand on orthopaedic services.

DHS has been proved to be a gold standard method of treatment in uncomplicated extracapsular fractures. The introduction of Intramedullary devices has provided us with a wider choice of construct. Since there was conflicting literature evidence comparing the outcomes of DHS and IMHS, we set out to analyse the same in our practice.

Forty patients in each group operated in the year 2000, comparable in fracture pattern, age and sex distribution were studied. The operating time, fluoroscopic exposure, blood loss, complications (Intra-op, Post-op and Deaths), duration of hospital stay and the discharge destinations were studied from the clinical notes and Hospital information system. Statistical analysis was carried out using SPSS for all the available data.

Statistically, the DHS has a lesser duration of surgery, lower fluoroscopic exposure and lesser duration of hospital stay. However, clinically it appears that the IMHS is fraught with more complications.

Between April 1992 and July 2005, 310 posterior lip augmentation devices were used for the treatment of recurrent dislocation of the hip in 307 patients who had received primary total hip replacements (THRs) using Charnley/Charnley Elite components with a cemented acetabulum. The mean number of dislocations before stabilisation with the device was five (1 to 16) with a mean time to this intervention from the first dislocation of 3.8 years (0 days to 22.5 years). The mean age of the patients at this reconstruction was 75.4 years (39 to 96).

A retrospective clinical and radiological review was carried out at a mean follow-up of six years and nine months (4.4 months to 13 years and 7 months). Of the 307 patients, 53 had died at the time of the latest review, with a functioning THR and with the posterior lip augmentation device in situ. There were four revisions (1.3%), one for pain, two for deep infection and one for loosening of the acetabular component. Radiolucent lines around the acetabular component increased in only six cases after insertion of the device which was successful in eliminating instability in 302 patients, with only five further dislocations (1.6%) occurring after its insertion.

Current methods for restoring or preserving limb length following total hip arthroplasty are anatomically inaccurate, as they do not consider acetabular and femoral height independently. In order to address this, we present and evaluate a technique that uses the transverse acetabular ligament to control the vertical height of the acetabular component and a caliper that controls the vertical placement of the femoral component within the femoral canal. Limb lengths were measured in 200 patients who had undergone primary total hip arthroplasty using this technique. Using this method, 94% had a post-operative limb length inequality that was 6 mm or less when compared to the normal side (average +0.38 mm). The maximum measured limb length inequality was ± 8 mm.

We report a series of 668 patients (699 hips) with an average follow up of 10.5 years (range, 10–11 years) following THR using a cemented custom-made titanium femoral stem and a cemented high-density polyethyl-ene acetabular component. The fate of every implant is known.

The mean age at operation was 68 years (24 – 94 years). The indication for THR was as follows: primary OA (629), RA (18), AVN (10), intracapsular femoral neck fracture (5), Perthes disease (3), developmental hip dysplasia (2) and SUFE (1). The mean pre-operative Harris Hip Score was 19 (range 10 – 42).

One hundred and seventy-four patients (26%) were deceased at the time of their 10-year review. Four hundred and ninety-four patients were subsequently reviewed of which 88 patients (13%) were assessed by telephone review as they were too frail to attend.

The average 10-year Harris Hip Score was 92 (range 43 – 100). The average 10-year Oxford Hip Score was 19 (range 12 – 46). 99.2% reviewed at 10 years stated that they were satisfied with their THR.

Revision surgery occurred in 21 cases (3%). Seventeen femoral components were revised for infection, one for recurrent dislocation and one was iatrogenically loosened during socket revision. There were no cases of revision for aseptic loosening of the stem. Dislocation occurred in 18 cases, of which 4 became recurrent (0.6%). Six patients had a postoperative sciatic nerve palsy (0.9%) with 4 making a full recovery. There was one case of femoral nerve palsy. Eleven patients developed a DVT (1.6%). Six patients had a PE (0.9%) all of which were non-fatal. There were 16 deep and 3 superficial wound infections. Thirty-eight patients had symptomatic trochanteric bursitis post-surgery.

In conclusion, the 10-years results of the custom femoral stem are encouraging with an overall high level of patient satisfaction.

Polyethylene wear remains an important cause of failure in knee replacements. Retrieval studies, simulators and simple X-ray methods produce wear data that may be inaccurate or unrealistic. We have developed an accurate RSA system for measuring wear in-vivo. Using this system we have found wear rate in a fixed bearing TKR to be about 0.1mm/yr[1]. In this abstract we extend the study to fully congruent mobile bearings.

Four Oxford uni-compartmental knee replacements, with excellent clinical results were studied ten years after implantation. RSA X-rays were taken in double leg stance with the knee in full extension and 15 and 30 degrees flexion. Following RSA calibration, silhouettes of the components on the stereo X-rays were extracted using a Canny edge detector and were matched to silhouettes projected using CAD models to determine the 3D component position. The average minimum thickness of the bearing was determined and was compared with the measured minimum thickness of 14 unused bearings to calculate linear penetration.

The average linear penetration after average 10 years implantation (range 8.5 to 10.25 years) was 0.16 mm (SD 0.13 mm). The average penetration rate was 0.017 mm/year (SD 0.011 mm/year). The maximum linear penetration rate was 0.027 mm/year.

The penetration rate is similar to that obtained in a retrieval study [2]. Compression of the bearing is minimal due to 6sqcm of contact area. This study therefore demonstrates that polyethylene wear on the upper and lower surfaces is minimal in fully congruous mobile bearing knee replacements.

Leg-length inequality is not uncommon following primary total hip arthroplasty and can be distressing to the patient. An excellent clinical result with respect to pain relief, function, component fixation, range of motion and radiographic appearance can be transformed into a surgical failure because of patient dissatisfaction due to leg-length inequality.

Postoperative leg-length discrepancy was determined radiographically for 200 patients who had had a primary custom total hip arthroplasty. In all cases the opposite hip was considered to have a normal joint center.

The femoral component was designed and manufactured individually for each patient using screened marker x-rays. A graduated calliper was used at the time of surgery to control depth of femoral component insertion. The transverse acetabular ligament was used to control placement of the acetabular component and therefore restore acetabular joint center.

Using this method 94% of subjects had a postoperative leg-length discrepancy that was 6mm or less when compared to the normal side (average, +0.38mm). The maximum value measured for leg-length discrepancy was +/−8mm.

We describe a simple technique for controlling leg length during primary total hip arthroplasty and propose an alternative radiographic method for measuring leg-length discrepancy.

Introduction: Wear, and the resultant loosening and revision, of Total Hip Replacements (THRs) remains the limiting factor in the long term success of the prosthesis. Over 1 million Total Hip Replacements (THRs) are implanted each year, of which about 15% are revisions, most of which are a consequence of loosening of either femoral or acetabular components. This is frequently caused by either the mechanical (Wroblewski, 1986) or biological (Besong et al, 1997) response to the wear of ultra-high molecular weight polyethylene (UHMWPE) acetabular component.

In a previous study Bennett (2002, 2000) has demonstrated that the walking patterns of THR patients 5 years post operation directly correlated with the wear of the acetabular component, as measured radiographically. The present study considers THR patients 10 years post-operatively, ensuring more accurate wear measurements and more meaningful outcome measures.

Materials and Methods: Gait Analysis was performed on a number of THR patients following routine review using a Vicon 370 data capture system and a lower body marker set. This data was processed using Polygon software and joint angles were derived for the hip in the sagittal, coronal and transverse planes. A computer simulation was used to determine the path which each of 20 points on the prosthetic femoral head traces on the acetabulum during walking.

Results: It was found that patients exhibited different patterns of movement ranging from liner to multi-directional. Normal subjects have previously been found to exhibit multi-directional movement. Patients with mult-directional movement showed evidence of greater wear (Bennett et al., 2000).

Discussion and conclusion: Linear movement causes orientation hardening and wear resistance while multi-directional movement cause increased shear and greater wear rates. These differences in movement loci have a significant influence on UHMWPE wear rate and the long term survival of the implant.

To maximise the long-term survivorship of any hip prosthesis it is important to recreate joint centre. Normal joint centre is determined by horizontal offset and vertical height of the acetabular and femoral components. In this study joint centre and horizontal offset were analysed in 200 consecutive patients operated on from October 1998 in whom the opposite hip was normal. Joint centre was defined relative to the acetabulum and femur both pre- and post-operatively. On the acetabular side a horizontal line was drawn across the pelvis immediately below each teardrop. A vertical line was drawn at right angles through the middle of each teardrop. Acetabular offset was defined as the horizontal distance from the vertical trans teardrop line to head centre. For femoral offset a screened x-ray was taken to show maximum offset. The anatomical axis was drawn and the offset was defined as the distance from the anatomical axis to head centre.

Our results show on the acetabular side there was an overall tendency to leave the joint centre medial and so decrease acetabular offset. However, we found that 90% of our sockets were placed within 6 mm of normal joint centre. We attribute this accuracy to the principle of visualising the transverse acetabular ligament intra-operatively and using this landmark to control depth of socket insertion. Conversely, on the femoral side there was a slight tendency to increase the offset. Nevertheless, 98% of the custom stems were within 10mm of normal joint centre. When we looked at total horizontal offset i.e. the combination of femoral and acetabular offset we found that joint centre had been restored to within 10mm in 93% of cases.

This study confirms the effectiveness of the custom femoral stem and Duraloc socket in restoring joint centre.

Rapidly progressive cases of primary idiopathic hip osteoarthrosis are well known and recognised. The prevalence reported in the literature varies from 4–18%. Three types have been identified- type 1 (rapid), type 2 (moderate) and type 3 (delayed) depending on the duration of chondrolysis and the subsequent rate of bone loss per year.

We reviewed the charts of all patients deemed to be RPO type 1 who had underwent hip arthroplasty under the care of the senior author (DEB) over a two-year period in an attempt to identify risk factors, which may have contributed to the rapid progression of their disease. All patients were treated using a custom femoral stem and a spiked Duraloc cementless socket following careful preparation of the acetabulum.

We identified 34 patients (40 hips) with type 1 rapidly progressive osteoarthrosis. Over the same time period 991 patients had underwent primary total hip arthroplasty, giving a prevalence of 4%. Of the 34 patients, 29 were female of average age 70.6 years (range, 51–83 years). All of the bilateral cases (6 patients) were female. Body mass index (BMI) for the female group ranged from 20.6 to 41.1Kg/m² (average, 28.2kg/m²) whilst that for the males was on average 25.8Kg/m² (range, 23.4–29.7Kg/m²).

Preoperative erythrocyte sedimentation rate (ESR) was 18mm/hr on average for the female group (range, 2–65mm/hr) and ranged from 3–52mm/hr (average, 20mm/hr) for the male patients. The preoperative Oxford Hip Score averaged 51 points for the female group and 48 points for the male group.

A detailed review of occupational history did not reveal any common occupational hazard. The majority of patients were non-smokers and denied any regular alcohol intake. Twenty-two patients (65%) had a history of hypertension. Twenty-seven patients (79%) had a history of non-steroidal anti-inflammatory use (most common preparation-diclofenac). Twenty-four patients (71%) resided in a rural area.

When compared to a cohort of patients undergoing primary total hip arthroplasty over the same time period, the only statistically significant risk factor identified was female gender.

We conclude, that patients who develop rapidly progressive osteoarthrosis of the hip are difficult to identify due to the absence of specific clinical features. We also outline our experience in the management of these technically challenging cases.