Introduction Polyethylene wear debris is an important cause of failure in cemented total hip arthroplasty. As a result of the biological response to debris at the bone-cement interface, osteolysis and subsequent failure occurs in both femoral and acetabular components. Most acetabular components and liners are made of ultra high molecular weight polyethylene (UHMWPE). Cross-linking UHMWPE has been shown to significantly reduce abrasive wear in hip simulator studies. The wear rates measured in vitro do not always correlate with the wear rates measured in clinical studies[1]. Some new polyethylenes have shown catastrophic wear in clinical studies despite encouraging hip simulator study results[2]. The aim of this study was to compare the wear of standard UHMWPE to that of cross-linked UHMWPE (Longevity, Zimmer, Warsaw, USA)

Patients and Methods This was a prospective, double blind, randomised control trial. 50 subjects were recruited, all of whom received the cemented CPT stem and uncemented Trilogy liner (Zimmer, UK). Subjects were randomised to receive either a standard Trilogy liner or a Longevity liner at the time of operation. Both liners are identical in appearance. All liners were of a neutral configuration. RSA was used to measure linear wear. This was calculated by measuring the distance between the centre of the femoral head and the centre of the acetabular liner. The preliminary results of the study are presented.

Results Both groups underwent significant wear over two years. The two year linear wear of the cross-linked UHMWPE was 0.3mm (+/− 0.06mm, p< 0.001). The two year linear wear of the standard UHMWPE was 0.39mm (+/− 0.04mm, p< 0.001). No significant difference existed between the two groups (p=0.24). Both cohorts had around 0.15 to 0.2 mm of measured wear per year. Cross-linked UHMWPE therefore underwent less wear than standard UHMWPE at two years, however this difference was not statistically significant.

Discussion This study suggests that Longevity UHMWPE has similar wear properties to standard UHMWPE in the first two years following implantation. This does not correlate with in vitro hip simulator studies of Longevity polyethylene, which show a significantly lower wear rate than standard UHMWPE. It suggests that hip simulator studies may be of little value in predicting in vivo wear rates and that all new types of polyethylene should be evaluated clinically and radiologically prior to general release. Whether both cohorts continue to wear at similar rates will only be revealed through continued observation.

Aim: To report our experience and early results with flexible nailing for unstable or irreducible displaced proximal humeral fractures in children.

Material & methods: Between 1997 & 2004, 15 children with unstable or irreducible displaced fractures of the proximal humerus were treated with closed/open reduction and flexible IM nailing. There were 10 boys and 5 girls. The median age of the patients was 12.5 years (9–15). Thirteen children had a Salter – Harris II, Neer grade III/IV fracture and 2 children had metaphyseal fractures. The outcome assessment was performed using the shoulder score, clinical and radiological parameters.

Results: All fractures united. None of the patients had a clinically significant malunion/shortening. Three patients had irritation at the nail insertion site. One patient had a transient radial nerve neurapraxia. There were no other operative or postoperative complications. The flexible nails were removed at a median time of 6 months (1.5–10) in 12 patients and 3 patients are awaiting removal. At a median follow-up of 30 months (4–66) all patients had a normal or near normal glenohumeral motion, full strength and all reported regaining full pre-injury functional use of the involved extremity.

Conclusion: Flexible nailing can be used safely to maintain reduction in unstable or irreducible displaced fractures of the proximal humerus and allows early return to normal activities and function with minimal complications. This treatment is also useful in older children who have minimal remodelling potential.

Arthroscopic procedures may be associated with considerable pain in the first 24 hours. Intra-articular bupi-vacaine provides good analgesia but is short lasting. Intra-articular morphine has been shown to prolong postoperative analgesia in knee and ankle arthroscopy. The aim of this study is to assess the safety and analgesic effect of intra-articular morphine following day case wrist arthroscopy.

Ethical approval was firstly obtained. 31 patients were randomly assigned to one of 2 groups in a double blind clinical study. Group 1 received 5ml of 0.5% bupi-vacaine intra-articularly with 5mg of morphine subcutaneously. Group 2 received 5ml of 0.5% bupivacaine and 5mg of morphine intra-articularly. There were 15 patients (mean age 41.2 years) in group 1, and 16 patients (mean age 38.9 years) in group 2. Postoperatively pain was assessed using a 100mm visual analogue pain scale (VAPS) at 1, 2, 6 and 24 hours. Analgesia requirements were recorded at these times post operatively. The presence of nausea, vomiting, other complications and patient satisfaction were recorded.

Visual analogue pain scores did not show any significant difference between the groups at 1, 2, 6 and 24 hours. Supplementary analgesic consumption over the 24 hour period was slightly greater in group 1 than in group 2. None of the patients who had intra-articular Morphine had vomiting nor any other complications and did not require anti-emetics. Most patients in either group were satisfied with the level of postoperative analgesia.

Intra-articular bupivacaine with or with out morphine provides adequate postoperative pain relief following wrist arthroscopy. There seems to be little difference between the two methods studied.

Introduction: The Charnley Elite femoral component was first introduced in 1992 as a new design variant of the original Charnley femoral component (De Puy, Leeds, UK) with modified neck and stem geometry. The original component had undergone few changes in nearly forty years and has excellent long-term results.

Early migration of the new stem design was determined by Roentgen Stereophotogrammetric Analysis (RSA). Rapid early migration of a component relative to the bone, measured by RSA, is predictive of subsequent aseptic loosening for a number of femoral stems. As there was rapid early migration and rotation of the Charnley Elite stem, we predicted that the long-term results would be poor. An outcome assessment is required as stems of this type are still being implanted.

Materials and method: One hundred Charnley Elite stems, implanted in our centre between 1994 and 1997 were included in a prospective, cross-sectional follow-up study. Outcome measures include validated clinical scores (Charnley hip score, Harris hip score and Oxford hip score) and radiological scores (Gruen classification) as well as revision rates over the past 10 years.

Results: The preliminary analysis results are given. The mean time to follow-up was 8.28 years. 20 patients have died due to causes unrelated to their operations. 10 patients had stem revisions: 9 for aseptic loosening and 1 for a peri-prosthetic fracture. This indicates a significant 10% failure rate of the prosthesis in less than 10 years.

Preliminary clinical scores in the patients who had not undergone any subsequent surgery were adequate (Oxford Hip Score mean average of 23.9).

Thirteen percent of radiographs analysed had evidence of loosening, giving an overall loosening rate of 14% at 8 years.

Discussion and conclusion: The clinical follow-up supports the RSA predictions of early failure of the Charnley Elite femoral stem.

Introduction: The Birmingham Hip Resurfacing (BHR) is a metal on metal prosthesis with no published independent clinical studies. It is increasingly used as an alternative to stemmed prostheses in younger patients.

This study presents the 2 year migration results of the BHR femoral component using Roentgen Stereophoto-grammteric Analysis (RSA).

Methods: 26 hips in 24 subjects underwent a BHR, through the postero-lateral approach using CMW3G cement. RSA marker balls were placed in the cortical bone of the femur intra-operatively. The femoral component migration was measured at intervals of 3, 6, 12 and 24 months postoperatively using the Oxford RSA system. The implants were un-modified, geometric algorithms were used to identify the femoral component.

Results: The BHR femoral component showed no significant displacement from its immediate post-operative position. All components of migration showed no significant displacement in any direction, at 1 or 2 years.

Conclusion: The BHR femoral component does not migrate significantly within the first two post-operative years. Its’ migration compares favourably to other designs of femoral component. The BHR is therefore likely to remain stable in the future, as the majority of implant migration occurs within the first two years.

Aim: To evaluate our results of articulated hip distraction in children with a painful, stiff hip.

Materials & Methods: Between 1988 & 2003, 10 children underwent hip distraction and 7 have completed treatment. The diagnoses were varied, though the presentations were those of pain & stiffness of the hip, poor posture and gait. The Orthofix articulated hip device was used in all patients. The outcome assessment was performed by clinical and radiological review.

Results: The mean age of the patients was 13.7 years (Range 12–17 years). The primary diagnosis was SUFE- 3, Perthes-4, trauma-1, septic arthritis -1, chemotherapy induced -1. The mean fixator time was 12 weeks (range 10–14 weeks). The follow-up period ranged from 4–183 months. Soft tissue releases and joint debridement were done in 6 and 2 patients respectively. Results were good in one, fair in five and poor in one patient. Patients with non-functional ankylosis gained functional position with some increase in range of motion. Grade 2 pin tract infections were noted in 4 patients.

Conclusion: Early results with hip distraction in this difficult, complicated group of patients are promising clinically and radiologically.

Introduction: This study investigates the influence of surgical approach on the early migration of a cemented Total Hip Replacement (THR), assessed by Roentgen Stereo-photogrammetric Analysis (RSA). Rapid early migration has been correlated with premature implant failure.

Method: 46 patients awaiting THR were allocated into Posterior Approach (PA) and Lateral Approach (LA) groups. RSA was used to assess post-operative stem position and migration at 1 year. Post-operative gait was examined for a subgroup of patients.

Results: There was no difference in initial stem position within the medulla. Significant differences in distal migration were found; (LA 0.78±0.07mm and PA 1.27±0.15mm), p< 0.01. Posterior head migration for the PA group (0.78±0.18mm) was twice that for the LA group (0.46±0.08mm), p< 0.05. The PA group showed greater medial migration of the prosthesis tip (0.62±0.24mm), compared to the LA group (0.11±0.08mm), p< 0.05. During gait, the legs of the PA group were relatively internally rotated when compared to those of the LA group.

Discussion: The PA implants rotate internally and into valgus further than the LA implants. The starting positions of the prostheses were the same with similar cement and prostheses characteristics. We can infer that surgical approach and therefore muscle function have a significant effect upon component migration. During gait, the PA group has relatively internally rotated legs, probably due to short external rotator weakness. Hence, the internally rotating torque on the femoral stem will be larger, explaining the rapid migration in this direction. With the LA approach, the abductors are likely to be damaged. Therefore, the PA joint reaction force will be more laterally directed, explaining the higher coronal plane rotation rates seen in this group.

Conclusion: Profound differences exist in early migration, between the LA and PA. Different muscle function may account for this and probably influences long-term outcome.

Aim: We present a review on RSD in children and emphasise the role of multidisciplinary team approach in the management of 13 children. Method: 3 boys and 10 girls with a mean age of 13 years and 4 months were reviewed before and after treatment. They were assessed for pain (visual analogue score) and function. A team-care approach was utilised and co-ordinated by the Orthopaedic Surgeon. Other members included a physiotherapist, clinical psychologist and the pain care team. Results: All the patients received physical therapy (land and hydrotherapy). 5 patients received guanethidine blocks and 10 required psychological support. The time to diagnosis ranged from 2 to 11 months. All the patients improved over a period of 2.5–7 months. Conclusion: Early diagnosis with aggressive multidisciplinary goal oriented team approach should form the basis of management in children with RSD.

The treatment of acetabular dysplasia in adolescents (age> 12) is difþcult and various complex pelvic osteotomies have been described. The aim of surgery being improvement in pain and to delay the onset of secondary osteoarthrosis. Methods: We present our experience of using the Tonnis triple pelvic osteotomy for treatment of acetabular dysplasia in the adolescent and adult age groups (range 13–27 years). This retrospective analysis includes 25 patients operated on over a nine year period (1991–2000) with an average followup of four years (range 2–8 years). More than 50% of the patients had had a previous open reduction or femoral osteotomy for CDH. Results: Radiographic analysis (pre & post op) included CE angle of Wiberg, Sharp-Ullmann index and the acetabular angle of the weight bearing zone. All parameters showed an improvement in the post operative analysis with an improvement in pain and range of movement in all patients. Discussion: The Tonnis triple pelvic osteotomy has the advantage of allowing the operator a direct þeld of view at all times and achieving a great deal of lateral rotation and medial displacement of the acetabulum due to the proximity of the osteotomy to the acetabulum. The ischial ramus and its ligaments to the sacrum are left intact, leading to greater stability of the pelvis and spine. Conclusion: Though technically difþcult and needing a long learning curve, it does improve acetabular alignment and symptoms in the early postoperative years. However long term studies are required to document its effect on the rate of secondary osteoarthrosis.

Aim: Small amounts of subsidence may be beneficial in stabilising a stem & appears to be a featue of polished tapered stems. Stem rotation (measured as posterior head migration) within the cement mantle, however, is probably a more important mechanism of failure than subsidence. Stems with a wider proximal portion are thought to better resist rotation. The CPS (Endoplus, UK) is such a device; here we compare its’ stability with that of the Exeter (Stryker-Howmedica, UK). Method: 20 patients received the CPS-plus stem & underwent RSA examinations at 3, 6 & 12 months postoperatively. The Exeter 1 year migration data (32 hips) was used as a comparison. Both groups underwent a Hardinge approach & the prosthesis was secured with CMW3G cement. Results: Both stems subsided about 1mm. The CPS showed less medio-lateral & A-P movement of the proximal stem than the Exeter over 1 year, as shown below: 1 Year Mean Migration ± SEM (mm) Discussion: The CPS internally rotates less than the Exeter, as demonstrated by the smaller amount of posterior head migration. It has a lateral flare of the shoulder; making its’ cross-section wider than the Exeter’s, this probably produces a greater resistance to rotation. The CPS also undergoes less medio-lateral proximal stem migration. Its’ lateral shoulder flare is probably responsible for this axial subsidence, as it prevents the shoulder from moving laterally whilst subsiding onto the calcar.

Increasing the width of the proximal section of a polished tapered stem enhances its rotational stability.

Aim: The purpose of this prospective study was to assess the outcome of scarfe osteotomy for hallux valgus. Method: 26 patients were reviewed but only the results of 24 patients (33 osteotomies) were available for analysis. The assessment involved the American Academy Foot and Ankle Society Score, pedobarographic & radiographic examination.

There were 3 male and 21 female patients with a mean age of 46 years. The mean follow up was 17 months. Statistical analysis was carried out. Results: The AAFAS score improved from a mean preoperative value of 52 to 89 postoperatively. The mean improvement was 34 (range 12–46). The inter-metatarsal and hallux valgus angles improved from a mean preoperative value of 15 and 31 degrees respectively to a mean postoperative value of 8 and 14 degrees. 22 patients (91.6%) were satisþed with the outcome of surgery. The pedobarographic results will be illustrated. In one patient a fracture occurred intra-operatively and two patients had wound infection which settled with antibiotics. Conclusion: The early results of the scarfe osteotomy for hallux valgus in our hands are encouraging.

The use of exhaust suit systems is commonplace in arthroplasty surgery where isolation of the surgical team is desirable in an attempt to reduce the risk of infection transmission. Elevated carbon dioxide levels have been reported in the non-clinical setting with such systems the consequences of which can include fatigue, diapho-resis, nausea, headache and irritability.

The aim of our study was to determine the levels of carbon dioxide present within an exhaust suit system during hip arthroplasty and to compare these with the recommended occupational exposure limit levels published by the Health and Safety Executive (HSE).

Data was collected during ten primary hip replacements performed by the same surgeon whilst wearing the Stryker Steri-Shield Helmet Exhaust System. This is a self-contained unit with an integrated blower used in conjunction with a full-length gown. In addition the helmet was fitted with an air-sampling probe connected to a portable infrared CO2 monitor and also a temperature probe. Thus continuous monitoring of both CO2 and temperature level during surgery was possible.

The mean initial CO2 concentration in the helmet at the beginning of surgery was 3 000 parts per million (ppm) and the mean maximum CO2 level recorded was 13 000 ppm. The mean time the surgeon was within an exhaust suit to perform a primary hip replacement was 1 hr 54 mins and for 86% of this time period the CO2 level within the helmet exceeded the recommended level of 5 000 ppm as stipulated by the HSE.

In conclusion we have demonstrated significantly elevated CO2 levels within the Stryker Steri-shield Exhaust Suit System during hip surgery. Surgeons who use this system should be aware of this together with the physical symptoms that may result.

The relative motion between a prosthesis, the cement mantle and its’ host bone during weight bearing is not well understood. Using Radiostereophotogrammetric Analysis (RSA), we examined the dynamically inducible micromotion that exists at these interfaces when an increased load is placed through the prosthesis.

Dynamically inducible micromotion was measured in the femoral components of 21 subjects undergoing total hip replacement with polished Exeter stems. Two standing RSA studies were performed, at 3 and 12 months postoperatively. Firstly in double-leg stance, and secondly fully weight bearing through the operated hip.

Subjects had no signs of clinical or radiological signs of loosening at 1 year. Significant micromotion was detected at the prosthesis-cement interface at 3 months.

Similar patterns of micromotion were observed at 12 months. The prosthesis appeared to bend during single-leg stance weight bearing, however this accounted for less than half of the total observed movement.

Conventional RSA studies were conducted at 3 months, 6 months and 1 year to confirm that the implants showed normal migration patterns.

This study demonstrates that movement exists between the prosthesis and bone during cyclical weight bearing. This dynamically inducible micromotion probably occurs at the prosthesis-cement interface. It could account for the wear that is observed on the surface of retrieved secure prostheses. This may be a mechanism by which failure eventually occurs.

The Birmingham reSurfacing Arthroplasty (BSA) is a metal on metal prosthesis with no published independent clinical studies. Despite this, it is increasing in popularity, especially as an alternative to stemmed prostheses in younger patients. This study presents the 1year migration results of the BSA femoral component using Roentgen Stereophotogrammteric Analysis (RSA).

Twenty six subjects underwent a BSA, through the postero-lateral approach using CMW3G cement, with RSA marker balls placed intra-operatively. The femoral component migration was measured at intervals of 3, 6 and 12 months using the Oxford RSA system. Geometric algorhythms were used to identify the femoral component. The data was examined for distribution prior to analysis. All statistical analysis was performed using the t-test.

The data was normally distributed. The 1 year migration results of the BSA femoral component are displayed below.

All cemented implants migrate in vivo. The majority of cemented stemmed implant migration occurs within the first post-operative year. High rates of migration within the first post-operative year correlate with premature component failure in some instances. The BSA is a fundamentally different design to most cemented prostheses, despite this we know that very large migrations, those in excess of 2mm/year in any direction are generally regarded as poor indicators of long term outcome. These results suggest that the BSA femoral component is an inherently stable device as it does not migrate significantly within the first post-operative year. Only long-term independent clinical studies and continued RSA follow-up will enable a comprehensive evaluation of the device.

Reflex sympathetic dystrophy is a syndrome characterised by pain and hyperaesthesia associated with swelling, vasomotor instability and dystrophic changes of the skin. It is rare in children, can occur without any previous history of significant trauma and may be recurrent and migratory.

We reported 13 new cases of RSD in children and emphasised the role of a multidisciplinary team approach in management. A review of the literature was included.

13 children (3 boys and 10 girls) with reflex sympathetic dystrophy were presented. They were aged between 8 and 17 years. Mean age at onset was 13 years 4 months. All of them had RSD involving the lower limbs. Thermography was performed in 10 cases. The average time to correct diagnosis was 4 months. Five ankles, 4 knees and 5 hips were involved (14 joints in 13 cases). Psychological assessments revealed abnormalities in all cases. Pain (visual analogue score) and function were assessed before and after treatment.

The most common therapy in children is progressive mobilisation supported by analgesic drugs, psychological and physical therapy. We individualised the therapy for each child. A team-care approach with the physiotherapist, psychologist and pain-care team co-ordinated by the Orthopaedic Consultant was the essence of our management. All children received physical therapy including a wide variety of non-standarised approaches involving analgesics and hydrotherapy. 5 patients received guanithidine blocks. Individual therapy was monitored with set achievable goals and weekly assessment of progression of mobility and joint motion.

Time from the first RSD episode to resolution averaged 6 months in our series [it was mean 10 weeks in the non-adolescent cases (8 cases) and 7 months in the adolescent one (5 cases)]. The pain and function scores improved remarkably in all patients.

RSD in children is not a widely recognised condition. There is often a delay in diagnosis in view of the rarity of the condition as well as the fact that specific diagnostic modalities are not readily available in all centres. Psychological factors should not be underestimated. Early diagnosis with an aggressive, multidisciplinary, monitored, ‘goal-oriented’ team approach should be the basis of management in these cases.

This study was designed to assess the standard of orthopaedic training of Senior House Officers in the U.K. and to determine the optimum time that should be spent in these posts before registrar training.

Two MCQ papers were constructed. One for the pre test and one for the post test. Questions covered all aspects of orthopaedics and trauma including operative surgery. The paper was firstly tested on controls including medical students, house officers, registrars of various grades and consultants. There was no statistical difference in the results for the two papers within the groups indicating that pre and post test papers were of similar standard. In addition the average scores in the tests increased proportionately to the experience and grade of the control.

129 SHOs from 25 hospitals in 10 different regions were tested by MCQ examination at the beginning of their 6-month post. They were again tested at the end of the job. The differences in score were compared. This difference was then correlated with the experience and career intention of the SHO.

There was no statistical difference between pre and post test results in all groups of SHOs in the study (student t test). The best improvement in scores during this six month period were seen in SHOs of 1–1.5 years orthopaedic experience. SHOs of more than 3 years experience demonstrated the smallest improvement in their score. There was a net loss of seven trainees with a career intention of orthopaedics to other disciplines.

In the vast majority of Senior House Officer posts in this country, very little seems to be learnt during a six-month attachment. This is especially so for those who are doing orthopaedics for the first time as well as very experienced SHOs.

To determine whether resection of osteophyte at TKR improves movement, 139 TKRs were performed on knees with pre-operative posterior osteophyte. Randomisation was to have either resection of distal femoral osteophyte guided by a custom made ruler or no resection. After preparation of the femoral bone cuts the ruler measuring 19 mm was placed just proximal to the posterior chamfer cut. The proximal end of this ruler marked the bone to be resected and this was performed using an osteotome at 45 degrees. Knees randomised to no resection had no further femoral bony cuts. Three months after implantation the patients had range of motion assessed.

One hundred and fourteen suitable knees were assessed, with 59 knees (57 patients) in the resection group and 55 knees (54 patients) in the no resection group. Full extension was more likely in the resection group (62%) than the group without resection (41%)(p=0.08). Flexion to at least 110 degrees was, however, less in the resection group (37%) than the no resection group (54%) (p=0.09).

Our study failed to show a statistically significant difference if the bony osteophyte is removed. There were however sharp trends, with statistically a one in ten chance these results would be different if the trial was repeated. Although there is no indication as to the cause of improved extension this could be explained by the release of the posterior capsular structures allowing full extension. The reduction in flexion is harder to explain and this may be due to increase in perioperative trauma and resultant swelling, possibly with fibrosis. Range of movement, particularly flexion, is known to improve up to 1 year post-operatively and assessment of these groups at that stage would be beneficial.

We present the results of treatment for relapsed infantile Blounts disease using a technique of hemiplateau elevation with the Ilizarov frame.

7 patients with a mean age of 10 years 6 months were reviewed at 30 months following hemiplateau elevation with/without ipsilateral tibial lengthening. Preoperatively clinical photographs, long leg standing radiographs and 3D computed tomography images were acquired. The patients were evaluated clinically (presence of knee pain, range of knee motion, knee stability and leg length discrepancy) and radiologically. Schoeneckers objective assessment was undertaken. The results were analysed statistically.

Clinically all the patients improved significantly. No patient had knee pain and the range of knee motion was from 0° to more than 100° of knee flexion. The radiological results and Schoeneckers grading are depicted below.

The improvement in radiological measurements were statistically significant. Pin site infection was present in all but settled with antibiotics.

The results of hemiplateau elevation for relapsed infantile Blounts disease are encouraging.

This study examined the effect of surgical approach on the 1year migration of the Exeter stem, using Roentgen Stereophotogrammetric Analysis (RSA). There is evidence that implants with increased early migration, particularly those moving into internal rotation, are likely to have a higher failure rate.

A total of 46 patients awaiting THR were allocated into 2 groups. Both groups underwent an Exeter Total Hip replacement, one through the Posterior Approach (PA), and the other through the Hardinge Approach (HA). RSA was used to assess post-operative stem position and migration at 1 year. Post-operative gait analysis and clinical evaluation was used to assess a subgroup of patients.

There was no difference in the initial stem position of each group within the femoral canal. Significant differences in migration were found for migration of the head distally and posteriorly and for the tip medially. During gait, the legs of the PA group were relatively internally rotated when compared to those of the HA group. Relative to the supporting bone, the PA implants internally rotate and also rotate into valgus further than the HA implants. The starting position of the prostheses was the same and the cement and prosthesis characteristics were similar. From this, we can infer that surgical approach and therefore muscle function, have a large influence on component migration. During gait, the PA group had internally rotated legs compared to the HA group. This is probably due to short external rotator weakness in the PA group. As a result the internally rotating component of the posteriorly directed joint reaction force on the femoral stem will be larger. This probably explains the rapid internal rotation seen in the implants of the PA group. With the HA group, because of abductor damage there is likely to be a smaller component of the joint reaction force acting on the stem. This would explain the smaller rates of observed coronal plain rotation (rotation into valgus).

Profound differences exist in early migration, between the HA and PA. Different muscle function may account for this and probably influences long-term outcome.

This early study examines the influence of a wider shoulder on the 1 year migration of a cemented, polished, tapered stem, using RSA.

Polished, tapered stems (PTS) have excellent 10 year survival rates. RSA studies have demonstrated that these devices subside about 1 mm / year. Small amounts of subsidence are beneficial in stabilising a stem. Stem rotation (measured as posterior head migration) within the cement mantle is probably a more important mechanism of failure than subsidence. Stems with a wider proximal portion are thought to better resist rotation. The CPS (Endoplus, UK) is such a device; here we compare its’ stability with that of the Exeter.

20 patients received the CPS-plus stem and underwent RSA examinations at 3, 6 and 12 months postoperatively. The Exeter 1 year migration data was used as a comparison. Both groups underwent a Hardinge approach with CMW3G cement.

Both stems subsided about 1mm. The CPS showed less medio-lateral and A-P movement of the proximal stem than the Exeter over 1 year, as shown below:

The CPS internally rotates less than the Exeter, as demonstrated by the smaller amount of posterior head migration. It has a lateral flare of the shoulder; making its cross-section wider than the Exeter’s, this probably accounts for its’ greater resistance to rotation. The CPS also undergoes less medio-lateral proximal stem migration. Its’ lateral shoulder flare is probably responsible for this axial subsidence, as it prevents the shoulder from moving laterally whilst subsiding over the calcar.

A PTS with a broad proximal section is more stable, this may confer an increased survival advantage.

Purpose: To determine if it is necessary to assess instability of the chronic anterior cruciate ligament deficient knee under general anaesthesia.

Materials and methods: 27 anterior cruciate ligament deficient knees in 27 patients were evaluated both subjectively using the Lachmanns and pivot shift test and objectively using the KT 1000 arthometer. This was done in the preoperative clinic (without the patient anaesthetised) and subsequently in the anaesthetic room with the patient anaesthetised (under general anaesthesia) prior to anterior cruciate ligament reconstruction. The data was prospectively collected. Only data on 21 knees was available for analysis. There were 20 females and one male with an average age of 29 years.

Results: There was no statistical significant difference (using students T test) between the data collected using the KT 1000 arthometer with and without the patient anaesthetised.

A significant difference was noted both for the Lachmanns (p< 0.01) and pivot shift test (p< 0.001) between the results obtained with and without anaesthesia. This however did not change the management.

Conclusion: Assessing the chronic anterior cruciate ligament deficient knee using the KT 1000 arthrometer, Lachmann and pivot shift test under general anaesthesia is not necessary if these assessments have been carried out in clinic.