We compared the outcome of patients treated for an intertrochanteric fracture of the femoral neck with a locked, long intramedullary nail with those treated with a dynamic hip screw (DHS) in a prospective randomised study.

Each patient who presented with an extra-capsular hip fracture was randomised to operative stabilisation with either a long intramedullary Holland nail or a DHS. We treated 92 patients with a Holland nail and 98 with a DHS. Pre-operative variables included the Mini Mental test score, patient mobility, fracture pattern and American Society of Anesthesiologists grading. Peri-operative variables were anaesthetic time, operating time, radiation time and blood loss. Post-operative variables were time to mobilising with a frame, wound infection, time to discharge, time to fracture union, and mortality.

We found no significant difference in the pre-operative variables. The mean anaesthetic and operation times were shorter in the DHS group than in the Holland nail group (29.7 vs 40.4 minutes, p < 0.001; and 40.3 vs 54 minutes, p < 0.001, respectively). There was an increased mean blood loss within the DHS group versus the Holland nail group (160 ml vs 78 ml, respectively, p < 0.001). The mean time to mobilisation with a frame was shorter in the Holland nail group (DHS 4.3 days, Holland nail 3.6 days, p = 0.012). More patients needed a post-operative blood transfusion in the DHS group (23 vs seven, p = 0.003) and the mean radiation time was shorter in this group (DHS 0.9 minutes vs Holland nail 1.56 minutes, p < 0.001). The screw of the DHS cut out in two patients, one of whom underwent revision to a Holland nail. There were no revisions in the Holland nail group. All fractures in both groups were united when followed up after one year.

We conclude that the DHS can be implanted more quickly and with less exposure to radiation than the Holland nail. However, the resultant blood loss and need for transfusion is greater. The Holland nail allows patients to mobilise faster and to a greater extent. We have therefore adopted the Holland nail as our preferred method of treating intertrochanteric fractures of the hip.

Purpose: To study acute effects of Intradiscal Electrothermal Therapy(IDET) on biomechanical properties of human intervertebral discs using Scanning Acoustic Microscopy(SAM) and 11.6 Tesla Nuclear Magnetic Resonance(μNMR)Microscope.

Materials and Methods: Five SpineCATH® IDET catheters (Smith& Nephew) were sited in the lumbar discs of a fresh frozen human cadaver under image control. 6 regions of interest (ROI) – anterior middle (AM), right anterolateral (RAL), left anterolateral(LAL), posterior middle(PM), right posterolateral (RPL) and left postero-lateral (LPL) were marked. These ROI were then subjected to SAM (50MHz, Kremer GmbH).

SAM was performed in C-scan mode(gate width 50ns, depth 3500ns) and acoustical data collected along X–Y plane/depth Z. A B- mode scan acquired acoustic data along X–Z plane/ depth A. Time-of-Flight (TOF) scan used to create 3D-like images based on distance between the top of the disc and maximum penetration depth.

The IDET catheters were heated according to the 90⁰C 16.5-minute protocol. Discs were subjected to SAM using identical protocols as described. The ROIs were incised and analysed using μNMR. A custom made device was fabricated to prevent rotational effects of varying orientation of the specimen in the magnetic field.

Results: 30 ROI were studied using SAM and μNMR. Acoustic Impedance was significantly decreased (p< 0.01)on SAM and these changes were confined only to LPL and LAL.

Non-linear regression analysis of Signal Intensity Ratios of 30 different regions using SPSS showed a significant change in T1 weighting on μMRI by a median factor of 40 ( IQR + 16) for the LPL and 20(IQR + 8) for LAL regions. Significant relaxation difference (p< 0.001) caused by “magic angle”effects wer noted in LPL compared to RPL.

Conclusion: This is the first study depicting structure of human intervertebral discs using 11.6T μMRI and SAM and exploring its clinical potential. The study irrefutably proves that IDET decreases stiffness coefficient only in the treated area. The findings on SAm closely mimicked findings on μMRI.

Revision of a failed acetabular reconstruction in total hip arthroplasty (THA) can be challenging when associated with significant bone loss. In cementless revision THA, achieving initial implant stability and maximising host bone contact is key to the success of reconstruction. Porous tantalum acetabular shells may represent an improvement from conventional porous coated uncemented cups in revision acetabular reconstruction associated with severe acetabular bone defects.

Methods: We reviewed the clinical and radiographic results of 46 acetabular revisions with Paprosky 2 and 3 acetabular bone defects done with a hemispheric, tantalum acetabular shell (Trabecular Metal Revision Shell, Zimmer, Warsaw, USA) and multiple supplementary screws for fixation.

Results: At a mean follow-up of 40 (24–51) months, one acetabular shell had been revised in a patient with a Paprosky 3B defect. Two liner revisions were performed for recurrent instability, without porous tantalum shell revision. The clinical outcome showed significant postoperative improvement in all measured sub-scales, compared with baseline pre-operative scores (mean improvement in Oxford Hip Score of 40.0, p < 0.001, in WOMAC of 36.7, p < 0.001, Physical component SF-12 of 12.3, p =0.0003, mental component of SF-12 of 6.8, p = 0.006). Radiographic evidence of osseointegration using validated criteria (Moore’s criteria) was demonstrated in 39 of the 40 hips available for radiographic analysis at a mean of 30.9 months, by two independent observers. Of the remaining six hips, five hips were lost to follow-up and one radiograph demonstrated failure of the hip reconstruction secondary to loss of fixation and superior migration of the component.

Discussion: Cementless acetabular revision with the porous tantalum acetabular shell demonstrated excellent early clinical and radiographic results in a series of complex revision acetabular reconstruction associated with severe bone defects. The evidence of radiographic osseointegration suggests that outcome should remain favourable, however, further longer-term evaluation is warranted.

Introduction: Deep infection in total hip replacement can be devastating. We report the outcomes 10–15 years after two stage revision for hip infection in 103 patients using the PROSTALAC (prosthesis of antibiotic-loaded acrylic cement) hip.

Methods: All patients or their next of kin were contacted to determine their current functional status and whether they had required repeat surgery or had recurrent infection. The Oxford-12, SF-12, and WOMAC questionnaires were administered. A comprehensive chart review was undertaken to review the infective organisms, surgery, approach, complications, and need for further revision surgery.

Results: 11 patients had re-infection, 7 of whom responded to repeat surgery with no further sequelae. Two patients required resection arthroplasty, one patient underwent hip disarticulation after eventual failure of treatment and bone loss, and one immuno-compromised patient developed osteomyelitis and was subsequently lost to follow-up. Long-term success rate for two stage-revision is thus 89%, or 96% with additional surgery. Since then, 3 patients required revisions for aseptic loosening, 1 for recurrent dislocation. We were able to follow up 45 patients, 75 % of whom provided health-related quality of life outcome scores. 39 patients were deceased, with their outcome confirmed via their last follow-up or with family members, for a total follow-up rate of 85 %. 15 patients were lost to follow-up, but did not undergo further surgery or have reinfections treated at our centre.

Discussion: Two-stage revision for hip infection, which includes an interim prosthesis of antibiotic loaded cement, offers a predictable and lasting solution for patients with this difficult problem.

Introduction: The aims of this study were to

determine predictors of pain, function and activity level 1–2 years after revision hip arthroplasty and

Methods: A prospective cohort of 222 patients who underwent revision hip arthroplasty were evaluated. Predictive models were developed and proportional odds regression analyses were performed to identify factors that predict quality of life outcomes at 1 and 2 years post surgery. The dependent outcome variables were WOMAC function, pain and UCLA activity. The independent variables included patient demographic, surgery specific and objective parameters including baseline Western Ontario McMaster Universities (WOMAC) osteoarthritis index, and the Short Form-12 mental component. The Loess method was used to plot the change of WOMAC and SF-12 scores over time.

Results: There was a significant improvement (p< 0.001) in all patient quality of life scores from baseline with results plateauing at 1 year. UCLA activity remained static between 1 and 2 years. In the predictive model, higher baseline WOMAC function (p < 0.001), age between 60–70 (p< 0.037), male gender (0.017), lower Charnley class (p < 0.001) and diagnosis of aseptic loosening (p < 0.003) were significant predictors of improved function.

When considering WOMAC pain as an outcome variable, factors predictive of improving category outcome included baseline WOMAC function (p= 0.001), age between 60–70 (p< 0.004), male gender (p= 0.005), lower Charnley class (p< 0.001) and no previous revisions (p < 0.023). Baseline WOMAC pain did not predict final pain outcome. Baseline WOMAC function (p=0.001), the indication for the operation (p=0.007), and the operating surgeon were significant predictors of UCLA activity at follow up. Peri or post-operative complications were not an adverse predictor of physical function, pain or activity.

Conclusions: Predictors of quality of life outcomes after revision hip replacement-showed that although some patient specific and surgical specific variables were important, age, gender, Charnley class and baseline WOMAC function had the most robust associations with outcomes.

Introduction: This single incision, anterolateral intermuscular approach (AL-IM) utilizes the interval between gluteus medius and tensor fascia lata. The aims of the study were to compare the quality of life, satisfaction and complications of this approach with two of the most commonly used limited incision transmuscular (TM) approaches, namely the mini-posterior (P-TM) and the mini-direct lateral (L-TM).

Methods: 199 patients receiving MIS THA surgical procedures were evaluated prospectively (63 AL-IM, 68 P-TM and 68 L-TM). The outcome variables were WOMAC function, pain, stiffness, SF-12 (physical & mental), Oxford-12, satisfaction and radiological outcome. Parametric and non-parametric analyses were performed.

Results: There were no significant differences between groups in baseline characteristics including age, sex, BMI, co-morbidity, or pre-op WOMAC, SF-12, Oxford-12 (p> .05). However, the AL-IM group was associated with superior outcomes (p< .05) in WOMAC function, WOMAC pain, global WOMAC, Oxford-12 and SF-12 physical component.

Conclusion: In the short term the AL-IM approach provides significant improvements in quality of life scores over other limited incision approaches. It provides minimal soft tissue disruption and maintains the abductor musculature and posterior soft tissue envelope, with similar complications and radiological outcomes.

To evaluate the results of open reduction in unreduced posterior dislocation of the elbow, done irrespective of the time since injury or age of the patient. Ten such cases in which the dislocation had been unreduced for more than 3 weeks since injury were included. Stiffness of the elbow was the main indication for the operation. Average age of the patient was 34.3 years (range 13 years to 65 years). Average time since injury was 3.9 months (range 2 month to 6 months). 3 patients had associated fractures around the elbow joint. All the patients had non functional elbow motion to perform any activity of daily living. We used speed’s procedure in all cases. At an average follow up of 18.5 months (range from 11 to 28 months), 8 patients achieved functional range of motion for activities of daily living and maintained an average arc of flexion(median) of 100 degrees and an average supination – pronation arc of 139.5 degrees. According to the Mayo Elbow Performance Index 5 patients achieved excellent results, 3 achieved good results and 2 achieved poor results. Complications included 2 cases of pin site infection, 1 case of ulnar neuritis and 1 case of delayed wound healing. We conclude that open reduction can provide painless, stable and functional elbow even in cases which are unreduced up to 6 months after the original injury.

Aim: To assess patient and surgery related factors to identify any trend leading to a stiff TKR. We also looked at the efficacy of MUA in the treatment of a stiff TKR.

Material and Methods: Retrospective analysis of TKRs which have undergone MUA during the period from 01/01/1999 to 25/06/2005 at Peterborough Hospitals. We included primary TKRs with a minimum post MUA follow-up of six months.

Results: Out of a total of 1809 TKRs, 42 TKRs (2.3%) in 38 patients required MUA. 26 (68%) were females with a median age of 67 years and a median BMI of 30. 34 (81%) had varus knees. Median pre-operative flexion was 100 deg. Median follow-up was 12 months (6 – 45 months). Median pre MUA flexion was 70 deg (15 – 100 deg.). Median surgery to MUA interval was 12 weeks (range: 10 days to 104 wks). Median gain in flexion during MUA was 35 deg (0 – 90 deg). At final follow-up, 74% had lost flexion gained at MUA (median loss: 17.5 deg, mean loss: 20 deg). 71% gained a median of 20 deg flexion with MUA (Mean: 25 deg, range: 15 – 85 deg). Median range of flexion at final follow-up was 90 deg (40 – 120 deg).

Conclusion: We were unable to identify any distinct trends in relation to BMI, pre op flexion, other patient or surgical factors that would help predict occurrence of a stiff TKR. We advocate the use of MUA for a stiff TKR. 71% patients gained 20 to 25 deg flexion with MUA. 74% patients lost about 20 deg flexion gained at MUA. The average post MUA flexion at final follow up was 90 deg. This information is useful when counselling patients undergoing MUA. A protocol for management of stiff TKR is suggested.

Contracture of the collateral ligaments is considered to be an important factor in post-traumatic stiffness of the elbow. We reviewed the results of isolated release of the medial collateral ligament in a series of 14 patients with post-traumatic loss of elbow flexion treated between 1998 and 2002. There were nine women and five men with a mean age of 45 years (17 to 76). They were reviewed at a mean follow-up of 25 months (9 to 48). The operation was performed through a longitudinal posteromedial incision centred over the ulnar nerve. After decompression of the ulnar nerve, release of the medial collateral ligament was done sequentially starting with the posterior bundle and the transverse component of the ligament, with measurement of the arc of movement after each step. If full flexion was not achieved the posterior half of the anterior bundle of the medial collateral ligament was released.

At the latest follow-up, the mean flexion of the elbow improved significantly from 96° (85° to 115°) pre-operatively to 130° (110° to 150°) at final follow-up (p = 0.001). The mean extension improved significantly from 43° (5° to 90°) pre-operatively to 22° (5° to 40°) at final follow-up (p = 0.003). There was a significant improvement in the functional outcome. The mean Broberg and Morrey score increased from a mean of 54 points (29.5 to 85) pre-operatively to 87 points (57 to 99) at final follow-up (p < 0.001). All the patients had normal elbow stability.

Our results indicate that partial surgical release of the medial collateral ligament is associated with improved range of movement of the elbow in patients with post-traumatic stiffness, but was less effective in controlling pain.

The study was established to assess the long-term results and differences between autogenous and synthetic anterior cruciate ligament (ACL) reconstruction.

We randomised 50 patients into 2 groups: 26 (52%) underwent reconstruction with middle third patellar tendon graft (PTG) harvested using the ‘Graftologer’ (Neoligaments) and 24 (48%) underwent reconstruction with the Leeds-Keio ligament (LK).

Subjective knee function was assessed using the Lysholm score, Tegner activity score, IKDC grading, and clinical assessment of anterior knee pain. Laxity was tested clinically, including anterior draw at 20° (Lachman), pivot shift, and arthrometric measurements using the Stryker laxometer.

At five years we have noted no significant difference in Lysholm scoring and Pivot shift between the LK group and patellar tendon group. But there was a significant difference in Tegner activity level and IKDC activity scores with PTG faring better at five years. There is no significance difference in anterior knee symptoms between the groups.

Conclusion: Due to the success of PTG/Hamstring in routine primary ACL reconstruction there does not seem to be a role for artificial ligaments. However, if we just look at functional outcome and patient satisfaction, LK patients seem to be doing as well as PTG at five years. So, there may be a place for the Leeds Keio graft where autologous tissue is unavailable.

There exists a lot literature referring to the cementing technique of hip replacements, but when talking about longevity of knee prostheses only seldom the cementing technique is mentioned even though 90% of the knees are cemented. Especially the tibial component, that has to cope with different forces such as pressure, rotation, tilt and sliding, is said to last longer when cemented.

Cementing Technique: There are many aspects that need to be thought of when cementing knee prostheses:

The preparation of the bone: The preparation of the surface of the bone is of great importance, as the-bond of the cement with the bone is by the shape of the surfaces and not by a chemical reaction. A good penetration of the cement into the cancellous-bone enlarges the connecting surface and optimizes the power transmission. The pulse-lavage is the most effective to open the spongy bone. Sclerotic bone needs to be penetrated.

When cementing knee prostheses one should give high attention to the cementing technique as especially a good anchorage of the tibial component will lead to longevity of the implant.

A prospective cohort of 222 patients who underwent revision hip replacement between April 2001 and March 2004 was evaluated to determine predictors of function, pain and activity level between one and two years post-operatively, and to define quality of life outcomes using validated patient reported outcome tools. Predictive models were developed and proportional odds regression analyses were performed to identify factors that predict quality of life outcomes at one and two years post-operatively. The dependent outcome variables were the Western Ontario and McMaster Osteoarthritis Index (WOMAC) function and pain scores, and University of California Los Angeles activity scores. The independent variables included patient demographics, operative factors, and objective quality of life parameters, including pre-operative WOMAC, and the Short Form-12 mental component score.

There was a significant improvement (t-test, p < 0.001) in all patient quality of life scores. In the predictive model, factors predictive of improved function (original regression analyses, p < 0.05) included a higher pre-operative WOMAC function score (p < 0.001), age between 60 and 70 years (p < 0.037), male gender (p = 0.017), lower Charnley class (p < 0.001) and aseptic loosening being the indication for revision (p < 0.003). Using the WOMAC pain score as an outcome variable, factors predictive of improvement included the pre-operative WOMAC function score (p = 0.001), age between 60 and 70 years (p = 0.004), male gender (p = 0.005), lower Charnley class (p = 0.001) and no previous revision procedure (p = 0.023). The pre-operative WOMAC function score (p = 0.001), the indication for the operation (p = 0.007), and the operating surgeon (p = 0.008) were significant predictors of the activity assessment at follow-up.

Predictors of quality of life outcomes after revision hip replacement were established. Although some patient-specific and surgery-specific variables were important, age, gender, Charnley class and pre-operative WOMAC function score had the most robust associations with outcome.

We report 79 cases of bone and joint tuberculosis between 1988 and 2005, eight of which were in the Caucasian population and 71 in the non-white population.

The diagnosis was made in the majority (73.4%) by positive bacteriology and/or histology. The mean age at the time of diagnosis was higher in the Caucasian group at 51.5 years (28 to 66) than in the South Asian group at 36.85 years (12 to 93). Only one patient had previous BCG immunisation.

The spine was the site most commonly affected (44.3%). Surgical stabilisation and/or decompression was performed in 23% of these cases because of cord compression on imaging or the presence of neurological signs.

A six-month course of chemotherapy comprising of an initial two months of rifampicin, isoniazide, pyrazinamide and sometimes ethambutol followed by four months treatment with rifampicin and isoniazide, was successful in all cases without proven drug resistance.

We describe the influence of the angle of immobilisation during partial weight-bearing on the forces across the extensor mechanism of the knee. Gait analysis was performed on eight healthy male subjects with the right knee in an orthotic brace locked at 0°, 10°, 20° and 30°, with the brace unlocked and also without a brace. The ground reaction force, the angle of the knee and the net external flexion movement about the knee were measured and the extensor mechanism force was calculated.

The results showed a direct non-linear relationship between the angle of knee flexion and the extensor mechanism force. When a brace was applied, the lowest forces occurred when the brace was locked at 0°. At 30° the forces approached the failure strength of some fixation devices. We recommend that for potentially unstable injuries of the extensor mechanism, when mobilising with partial weight-bearing, the knee should be flexed at no more than 10°.

In a 41-year-old man, right-sided infraspinatus muscle weakness was associated with compression of the suprascapular nerve caused by a spinoglenoid ganglion cyst. The lesion was confirmed using electromyography and MRI. In addition, arthroscopy showed an incomplete discoid labrum. The free inner edge of the labrum was removed as in a meniscectomy of a discoid meniscus in the knee joint. Arthroscopic decompression of the cyst was performed through a juxtaglenoid capsulotomy which was left open. Neurological function recovered completely.

Surgical access to the head of the radius is usually performed through a lateral approach. We present an alternative technique through a modified posterior approach which was developed following dissections of 22 human cadavers. An osteotomy of the supinator tuberosity was performed and reflected as a single unit with the attached annular ligament. Excellent exposure of the head of the radius was achieved, replacement of the head was undertaken and the osteotomy site repaired. The elbows were stable and had a full range of movement. The approach was then carried out on 13 patients for elective replacement of the head and was found to be safe and reproducible. In the patient group all osteotomies united, the elbows were stable and had an improved range of supination and pronation. There was no change in flexion and extension of the elbow. Complications included a haematoma and a reflex sympathetic dystrophy.

The modified posterior approach provides excellent access to the head and neck of the radius, gives good stability of the elbow and allows early mobilisation of the joint.

Fragility fractures of the ankle occur mainly in elderly osteoporotic women. They are inherently unstable and difficult to manage. There is a high incidence of complications with both non-operative and operative treatment.

We treated 12 such fractures by closed reduction and stabilisation using a retrograde calcaneotalotibial expandable nail. The mean age of patients was 84 years (75 to 95). All were women and were able to walk fully weight-bearing after surgery. There were no wound complications. One patient died from a myocardial infarction 24 days after surgery. The 11 other patients were followed up for a mean of 67 weeks (39 to 104).

All the fractures maintained satisfactory alignment and healed without delay. Six patients refused removal of the nail after union of the fracture. The functional rating using the scale of Olerud and Molander gave a mean score at follow-up of 61, compared with a pre-injury value of 70.

Introduction: Intra-Discal Electrothermal Therapy (IDET) has been used to treat chronic discogenic low back pain. A novel intradiscal decompression catheter has been developed to reduce local disc bulging in cases of contained prolapse. This new catheter is inserted percutaneously into a disc and advanced under radiographic control into a postero-lateral position targeting the herniation. The decompression catheter uses more focused heating and higher temperatures than previous devices and is intended to provide a local decompression of the disc through a thermally mediated reduction in nuclear volume. The purpose of this study was to investigate changes in internal stress profiles following use of the new catheter.

Methods: Five cadaveric lumbar ‘motion segments’ were dissected from two spines (age 64–84 yrs). Each segment was compressed, normally to 1 kN, while a miniature pressure transducer was withdrawn from posterior to anterior across the mid-sagittal diameter of the disc producing a baseline stress profile. A decompression catheter was inserted into the disc and its position confirmed with plain radiography. The temperature of the catheter was increased to 90°C over a period of 14 minutes. Stress profiles were then repeated.

Results: Stress profiles in three of the five segments showed changes consistent with degenerative change. In these discs stress profiles following ‘treatment’ showed up to a 35% reduction in the magnitude of stress peaks in the posterior annulus. There was very little change in the distribution of stress in the two non-degenerate discs. Stress in the nucleus appeared unchanged in all discs.

Conclusions: Treatment of degenerate discs with the decompression catheter lead to a measurable alteration in annular stress peaks associated with degenerative discs, while non-degenerate discs were unaffected. These preliminary findings of an ongoing study suggest that the novel decompression catheter has a biomechanical effect in certain classes of disc.

We studied 16 hips (eight cadaver specimens) using arthrography, arthroscopy and anatomical dissection, under incremental traction of up to a maximum of 64 kg, to determine the relationship of the portals to nearby neurovascular structures.

The distance of each arthroscopic portal (anterior, anterolateral, and posterolateral) to the associated neurovascular structures was measured after the application of 23 kg of traction.

Traction of up to 64 kg on the lower limb failed to produce evidence of labral or capsular injury. Furthermore, traction of 23 kg resulted in little change in the position of adjacent neurovascular structures relative to the standard arthroscopic portals.

The study was established to assess the long-term results and differences between autogenous and synthetic anterior cruciate ligament (ACL) reconstruction.

We randomised 50 patients into 2 groups: 26 (52%) underwent reconstruction with middle third patellar tendon graft (PTG) harvested using the ‘ Graftologer ‘ (Neoligaments), and 24 (48%) underwent reconstruction with the Leeds-Keio ligament (LK).

Subjective knee function was assessed using the Lysholm score, Tegner activity score, IKDC grading, and clinical assessment of anterior knee pain. Laxity was tested clinically, including anterior draw at 20° (Lachman), pivot shift, and arthrometric measurements using the Stryker laxometer.

At five years we have noted a slight reduction in Lysholm scoring in the LK group, as well as reduced Tegner activity level. Pivot shift and laxity were significantly greater in the LK group.

Compared with earlier results, which showed little subjective difference between the groups, the autogenous PTG group show more sustainable long-term results than the synthetic (LK) group. There is no significant difference in anterior knee symptoms between the groups.

The aim of this prospective study is to investigate the effectiveness of a new method for arthroscopic all-inside meniscus repair (Clearfix meniscal screw system-Innovasive Devices Inc.).This system consists of delivery cannulae,screw implants and a screw driver.After tear debridement a screw is located on the driver and passed through the cannula to the insertion site, holding the two sides of the tear together under linear compression.In this study, 46 patients (48 repairs)are included, mean age 32,7 years,with a follow-up ranging from 6 to 48 months (average 18,8 months).Only longitudinal lesions in the red/red zone or red/white areas were repaired. Ligament stabilizing procedures were done in 39 patients (84,8%) who had ACL deficient knees,.Thirty-four (71%) injuries were considered chronic (injury to repair time more than 4 weeks) and 14 (29%) injuries were considered acute (injury to repair time less than 4 weeks).The evaluation of the results was based on the clinical examination,the “OAK ” knee evaluation scheme and the MRI.Criteria for clinical success included absence of joimt line tenderness, swelling and a negative Mc Murray test.Thirteen out of 48 repairs (27%) were considered as failures according to the above mentioned criteria.The average time for the procedure was 8 minutes.Postoperatively there were no complications directly associated with the device.Magnetic resonance imaging, however,showed a persisting grade III and IV lesion in 72,8% of the patients (n=35) according to Reicher classification.

Though the system offers two main advantages,that is the absence of serious complications and the reduced operative time, the failure rate in this study is quite high. This clinical study is in agreement with the recent experimental studies referring to the limited pull-out strength of this device.

Removal of well-fixed, cementless, acetabular components during revision arthroplasty remains a challenging problem. Further damage to host bone may limit options for reconstruction and compromise the long-term result of the revision operation. We report the results of 31 hips with well-fixed, cementless sockets which were removed using a new cup extraction system. In all hips the socket was removed without difficulty and with minimal further bone loss.

Purposes of the study and background: This study tests the hypothesis that it is possible to visualise the cervical spine musculature using ultrasound. The use of diagnostic ultrasound is well established for assessing other anatomical regions; whereas the cervical spine has received little attention. Other available imaging procedures can be resource intensive with recognized risks and do not give an indication of structural detail. Ultrasound has the potential to resolve these inadequacies and would therefore be appealing.

Summary of the methods and the results: 10 healthy volunteers (age range: 21–36 years, 6 females, 4 males) were evaluated using a 8-16MHz linear array transducer (Diasus Dynamic Imaging, UK) and a 16MHz CL15-7 linear array scanhead transducer (Phillips ATL HDI 5000 SonoCT, Netherlands). Subjects were seated with their neck in a neutral position. The transducer was orientated transversely, and initially placed on the thyroid cartilage. Successive images were taken as the transducer was moved laterally across the anterior triangle, over the sternocleidomastoid, into the posterior triangle, ending in the posterior midline. Landmarks, with characteristic ultrasonic appearances, were identified to aid orientation e.g. carotid artery. Both machines produced images that clearly displayed the musculature of the cervical spine. Composite images were obtained of the anterior and posterior aspects of the neck (Figure 1) to provide information regarding the spatial orientation and relationship between the muscles.

Conclusion: This study concludes that modern ultrasound equipment provides cervical spine soft tissue images of a quality suitable for diagnostic applications. It also has the advantages of being a risk free, economic and portable procedure.

Purposes of the study and background: Diagnostic interventional procedures are often performed on patients who suffer from cervical facet joint pain and discogenic pain emanating from the cervical region. These procedures require radiographic imaging to confirm placement of instruments e.g. needles. However, these techniques are unable to provide real-time images hence prolonging the intervention. It would be of benefit to have an imaging tool that is capable of visualising needle insertion in real-time whilst preventing side effects. The purpose of this study was to determine the ultrasonic appearance of cervical facet joints in vivo and describe a standardized transducer position to visualise intervertebral discs and facet joints.

Summary of the methods and the results: 10 healthy volunteers (age range: 21–36 years, 6 females, 4 males) were evaluated using an 8-16MHz linear array transducer (Diasus Dynamic Imaging). Subjects were scanned in a prone, lateral position. The transducer was placed in the posterior triangle orientated longitudinally, initially along the posterior border of sternocleidomastoid and then moved in a cranial-caudal direction. By adjusting the angle (in the antero-posterior direction) of the transducer about a fixed position; facet joints and discs were located. The characteristic V shaped appearance of the facet joint emanates from the hyperechoic signal of the closely spaced transverse processes of adjacent vertebra (Figure1). Disc regions appeared as areas of high signal penetration into the spine with low amplitude signals returning from the disc.

Conclusion: The detail of facet joint and disc anatomy captured using ultrasound reveal it to be a viable imaging tool for interventional procedures. Noteworthy advantages of ultrasound include: its ability to provide real-time images economically, the option of portability and no known side effects.

There is a recognised incidence of anterior knee pain following Anterior Cruciate Ligament (ACL) reconstruction using a patella tendon autograft.

This study examined two group of patients both pre ACL ligament reconstruction and post ACL reconstruction using patella tendon grafts to define if anterior knee pain is a result of patella tendon harvest or a primary consequence of an ACL injury.

The two groups of patients were best matched for age, sex and physical activity.

The pre-operative group of twenty-five patients had a confirmed ACL rupture and exhibited symptoms of instability requiring an ACL reconstruction.

The operative group of twenty-five patients were a minimum of a year post operation.

The graft was harvested by an open procedure and the graft bone blocks were secured with interference screws.

The patients’ anterior knee pain score was assessed using the Shelbourne scoring system that evaluates knee function in relation to anterior knee pain using five parameters. The maximum score is 100.

The scores were compared using the unpaired student test.

There was no significant age difference between the two groups, preoperative group age 32. 2 years (range 22 to 46) and postoperative age 34. 8years (range 19 to 48).

The mean anterior knee pain score for the preoperative group was 71. 6 (49 to 100), the postoperative group was 77. 7 (45 to 100), this was not significantly different.

We found no significant difference in knee function due to anterior knee pain between the two groups. Studies have shown significant anterior knee pain following hamstring reconstruction (Spicer).

This study shows anterior knee pain in the ACL deficient knee is present prior to surgery.

We conclude that patella tendon autografts produce no significant incidence of anterior knee pain post surgery.

The purpose of this retrospective study was to analyze the indications for spinal instrumentation, report the clinical features, operative details and outcome in 16 patients with active pyogenic spinal infection.

Between January 1991 to October 1999, 81 patients with spontaneous pyogenic spinal infection were treated at the authors’ institution. Surgery (other than biopsy) was indicated in 24 patients for neurological deterioration, deformity or instability. Sixteen of these patients were treated with instrumentation in the presence of active spinal infection. Six patients underwent combined anterior and posterior procedures. 10 had a posterior procedure only. Outcomes assessed were control of infection, neurology, fusion, back pain and complications.

At a mean follow up period of 26. 9 months, all surviving patients were free of clinical infection. None of the patients had neurological deterioration. All patients who had neurological deficit preoperatively improved by at least one Frankel grade. A solid fusion was achieved in 15 patients. 12/15 patients remained asymptomatic or had very little pain. The remaining 3 patients had mild to moderate back pain. The mean correction of the kyphotic deformity was 18. 92 degrees. Postoperative complications included bronchopneumonia, nonfatal pulmonary embolism and seizures in 3 patients. One patient developed progressive kyphosis despite instrumentation but eventually fused in kyphus.

Given early recognition of pyogenic spinal infection, most cases can be managed non-operatively. Our results support that instrumented fusion with or without decompression may be used safely when indicated without the risk of recurrence of infection. Instrumentation facilitates nursing care and allows early mobilisation. For biomechanical reasons, a combined procedure is probably indicated for lesions above the conus. For lesions below the conus, we were able to achieve successful results with posterior approach only.

We have performed a study comparing the radiological results of Total hip replacements performed by a single, experienced specialist hip surgeon with those reported from the Trent Regional Arthroplasty Study (TRAS) [presented at BOA congress 2000]. Results from TRAS have revealed that inadequate cementation grades and a cement mantle width of < 2mm were the most significant associations predicting early aseptic loosening. Interestingly, their respective incidences were as large as 20% and 50% in a random sample of THRs from the TRAS register.

Data is lacking as to whether poorer radiographic cementation grades have a trend towards individual surgeons or whether they are more evenly distributed amongst the surgical population including those adhering to modem techniques.

Therefore, we have undertaken an independent review of A-P and lateral radiographs of 33 consecutive Charnley THRs performed by a specialist hip surgeon using carefully controlled modem cementing techniques and compared the results with the same random cohort of THRs from the TRAS.

Our results show that the specialist surgeon achieved a significantly higher proportion (82%) of complete cement mantles (> 2mm in all zones) than those achieved by TRAS (50%) [Chi²=7. 79, p=0. 0052]. This suggests that improved cement mantles can be achieved by the adoption of carefully controlled modem cementing techniques. However, use of the Barrack system of grading was unable to detect differences in cementation quality between specialist (88%) and TRAS group (81%) [Chi²=0. 235; p=0. 631 suggesting less sensitivity in this technique for assessing cementation quality. These results are important for the following reasons. Achievement of adequate mantle (> 2mm) can be improved upon by adoption of carefully controlled modem cementing technique. However, regardless of the method of assessment of cementation quality, approximately 18% will appear ‘inadequate’ despite modern techniques suggesting that factors outside the surgeon’s control are involved in determining cementation grade. This has important medico-legal implication in the current climate in which surgeons are being criticised, in negligence cases arising out of the 3M Capital Hip experience, for achieving ‘inadequate’ cementation.

Aims: To determine which radiological features were most significant in aseptic loosening (AL) of Charnley total hip replacement (THR) and to compare the prevalence of these features between a specialist hip surgeon and those from the general setting. Method: An analysis was performed of the initial post-operative radiographs of three groups of Charnley femoral stems: I: Failed stems within 5 years due to AL, as registered in the Trent Regional Arthroplasty Study (TRAS). II: 44 consecutive Charnley THRs performed by a single, ‘specialist’ hip surgeon. III Controls: A randomly selected cohort group from the TRAS (proven to be clinically and radiologically intact at 5 years). Results: The most significant radiographic features of failure were: (i) mantle width < 2mm in any zone giving an odds ratio of 21.0 for failure (CI 3.3 to∞; p< 0.05); (ii) “inadequate” cementation grade (Barrack grades C and D) giving an odds ratio of 9.5 for failure (CI 3.2 to 28; p< 0.05). The specialist hip surgeon achieved a significantly higher proportion (79.5%) of complete cement mantles (> 2mm) than the controls (50%) (Chi^2 = 9.455, df = 1, p=0.002). There were also a higher proportion of adequate cementation grades (88.6% vs 82%) although this difference was not significant (Chi^2= 0.947, df = 1, p=0.330). Conclusion: We have demonstrated features identified on radiographs of Charnley femoral stems predictive of failure. In our study a specialist hip surgeon achieved fewer flaws than those detected across a regional ‘average’. This suggests surgical technique can influence radiological results and thus outcome. This needs to be emphasized, particularly during training, in the hope of improving overall results in the future. However, even a specialist’s cementation appeared inadequate in 11.4% of cases, suggesting that factors outside the surgeon’s control, influence cement grading. This is important from a medico-legal standpoint because surgeons are being criticised for not achieving adequate cementation in negligence cases.

The corticosteriods in the treatment of Duchenne’s or Becker’s muscular dystrophies causes muscular weakness and osteoporosis characteristic of these patients and result in different fractures which are of difficult resolution because prolonged immobilization increases morbidity. How can this problem be solved in highly risk patients? The diverse models of external fixators have given us the possibility of treating them without immobilization and in consequence obtain a quicker return to previous functional status including gait .

4 patients with Duchenne’s and Becker’s muscular dystrophies were treated. 1 patient recovered its ambulatory ability and the rest maintain their gait. 1 of them still has an external fixator but he is able to walk. Patients presented a diaphyseal fracture of the femur, a proximal fracture of the tibia, an introchanteric fracture of the hip and a supracondylar fracture of the femur.

We consider that external fixators open an endless range of options, not very much used until recently, that help our patients to extend their functional status and gait. Patients accept them easily because they give them independence and avoid the depression that stems from the loss of capabilities.

Objective: To assess the validity of the Tokuhashi and Tomita scoring systems in the prediction of prognosis following spinal surgery for skeletal metastases.

Design: A retrospective cohort study of patients treated in a specialist spinal unit

Subjects: All patients undergoing definitive surgery for metastastes of the spine were considered eligible. Time to death or current length of survival was available in 147* of these which was confirmed by the Cancer Registry. Medical and nursing case notes were reviewed and prognostic scores using the methods of Tokuhashi et al, and Tomita et al. were calculated for each patient.

*

death data for further patients currently awaited from Cancer Registry.

Outcome measures: Mean survival period with 95% confidence intervals for patients grouped according to prognostic score.

Results: Thirty-two patients were still alive and 113 had confirmed death dates. Forty-three patients had Tokuhashi scores of 9 or greater with a mean survival of 20.1 months (95% confidence interval 5.8 months) compared to 9.5 months (2.9 months) for scores 6–8 and 3.5 months (1.8 months) for scores below this. Tomita scoring showed a similar trend with those with better prognostic profiles but without the same degree of statistical significance. The overall 30-day mortality was 8.2% with no significant difference between any other groups.

Conclusion: In patients presenting with metastatic disease involving the spine, published prognostic profiles offer some guidance to likely survival of the patient and so the appropriateness of surgical treatment.

Aim: We conducted a prospective, randomised study of 50 patients, 40 (80%) male and 10 (20%) female, with anterior cruciate ligament (ACL) rupture to compare the results of ligament reconstruction by middle third patellar tendon graft (M) or synthetic Leeds-Keio (LK) ligament.

Method: The patients were randomised into two groups. 26 (52%) underwent PTG repair and 24 (48%) LK repair. Subjective knee function was classified using the Lysholm score, Tegner activity score and IKDC grading. Laxity was tested by clinical examination including anterior draw, pivot shift and arthrometric measurements using the Stryker Laxometer (Stryker Corporation, Kalamazoo, Michigan, USA).

Results: We present the early (two to five-year follow-up) results of this on-going trial. There was no statistical difference between the two groups in activity levels, both pre-injury and current. However, both pivot shift and anterior laxity were significantly greater in the LK group at two years and greater.

Discussion: While the LK group did develop significantly greater laxity, it is demonstrated that the functional outcome is not affected. We conclude therefore that if the results of surgery were to be based on a functional outcome rather than objective measurements of laxity, it would seem logical that the LK is an acceptable alternative to autogenous PTG.

However whilst function appears to be as good the less successful objective criteria do suggest reservations for the long term results of the Leeds-keio graft.

Objective: To measure intradiscal pressures in scoliotic spines to further understand the role of mechanical forces in the development of scoliosis.

Design: Pressure readings were obtained in consented patients with ethical approval. A needle mounted pressure transducer was introduced into the disc during routine anterior scoliosis surgery.

Subjects: Ten human scoliotic discs from three patients.

Outcome measures: Intradiscal pressure profiles.

Results: Nuclear hydrostatic pressures varied from 0.2 to 0.6 MPa. The mean nuclear pressures for the three spines were 0.27+0.12, 0.35+0.06 and 0.47+0.12 MPa.

High stress, non- hydrostatic regions were consistently recorded in the concave annulus.

Conclusions: Nuclear pressures in these scoliotic patients were significantly higher than the 0.12 and 0.15 MPa recorded previously in non-scoliotic recumbent individuals^1;2 suggesting that spinal loading is abnormal in scoliosis.

Introduction: The progress of post tubeculous kyphosis in children during ‘growth spurt’ is unpredictable and has not been clearly documented in literature.

Methods: The progression of deformity in 63 children treated conservatively and belonging to a controlled clinical trial was studied over 15 years.

Results: The average Kyphosis increased from 35.2 degrees to 41.3 degrees in the ‘Active Stage’ (Phase I), there was an increase in all patients. In the ‘Healed stage’ (Phase II), a variable progress continued which was more prominent during the ‘growth spurt’. In Type I, there was a worsening which occured either continuously (Type 1a; n=19.30%), or suddently after a gap of few years (Type 1b;n=6.9%). In Type II, an improvement occured either after an initial increase or a plateau (Type IIa; n=18.29%), or continuously after disease cure (Type IIb; n=9.15%). In Type III, the deformity was static (n=11.17%). The average increase in Type Ia was 24.2 degrees, Type IIb was 20;5 degrees, Type Ib was 58.4 degrees; the decrease in Type IIa was 4.9 degrees, Type IIb was 20.5 degrees and the decrease in Type III was 1.7 degrees. Overall, the growth spurt sresulted in an increase in deformity in 25 (39%) children, a decrease in 27 (44%) and no change in 11 (17%).

Conclusion:

Post-tuberculous kyphosis in children is a ‘Dynamic deformity’ which changes till skeletal maturity.

Many factors have been demonstrated to influence the range of knee movement that an individual can achieve.

The purpose of this study was to objectively demonstrate how range of knee movement is affected when the influence of pain is abolished.

Sixty-eight patients with degenerative joint disease presenting for primary total knee arthroplasty were recruited. Using a digital camera, images were taken before and after the induction of anaesthesia with the lower limb in four positions- extension, forced extension, flexion and forced flexion. Camera set up was standard and the range of knee motion was measured from the digital images.

Average arc of motion before anaesthesia was 96° (range, 41°–157°). After induction of anaesthesia, the arc of motion increased to 115° (range, 410–161°). Knee extension improved by an average of 5° (range, 0–15°) and flexion improved by an average of 16° (range, 0–65°).

In conclusion, these results demonstrate that pain has a significant inhibitory effect on the measured range of knee movement before surgical intervention.

Dislocation of the polyethylene-rotating platform is a recognised complication of LCS knee arthroplasty.

We report ten cases of rotating platform dislocation out of 2151 primary total knee arthroplasties (0.5%) performed to date in our unit.

Of the ten cases (3 male: 7 female), six patients had a preoperative valgus deformity, two had a varus deformity and the remaining two patients were in neutral alignment, although the wear was predominantly within the lateral compartment. Two patients also had a previous patellectomy on the side of the platform spinout.

Of the ten cases, six patients were symptomatic as a result of their platform dislocation. The remaining four patients were asymptomatic and mobilising without any difficulty. In these patients, the dislocated platform was diagnosed on x-ray at outpatient review. Time to detection of the platform dislocation ranged from six days to two years.

Three patients required revision of their original insert to a larger, deeper dish insert. Three were managed by open reduction of the original insert. Of the remaining patients, one was managed successfully by closed reduction, one required an arthrodesis and one had the tibial insert cemented to the tibial tray. All patients at latest review have a functional and stable knee joint.

In conclusion, we feel that surgical error was to blame for the majority of our ten cases. Furthermore, we emphasise the importance of producing equal and balanced flexion and extension gaps at the time of knee arthroplasty in order to prevent mobile bearing dislocation. A novel technique for reducing a dislocated rotating platform is also described.

The aim of this trial was to assess the clinical examination findings commonly used for the ACL deficient knee.

For reliability testing and criterion validation 102 patients with ACL injuries were assessed by a single observer, 35 by a second observer and 47 again by the initial observer. For construct and criterion validation 30 patients were assessed pre-operatively and a mean of 1.7 years after ACL reconstruction. The Lysholm 11, Tegner and Cincinnati outcome measures were assessed along with instrumented knee laxity (Stryker test), the one hop test (OHT) and graded tests (including anterior draw, Lachman test, quality of end point, and pivot shift test).

The outcome measures were found to be reliable except the Cincinnati system. All examination findings were of unsatisfactory reliability, with the exception of the OHT and the Stryker test. Construct validation revealed a significant improvement in all outcome measure scores and examination findings following ACL reconstruction. Criterion validation revealed that of the examination findings only the OHT had a satisfactory correlation with the symptom of giving way and the Lysholm/Tegner measures. Comparison of the difference between the desired and actual Tegner activity levels with the examination findings revealed an improvement in all levels of correlation.

With the exception of the OHT, the clinical examination findings used for the ACL deficient knee are unreliable and correlate poorly with the functional outcome of the patient. They may, however, have some benefit in assessment of deficiency of the anatomical structures and the findings should be presented individually, rather than forming part of the functional assessment of the patient.

The aim of this randomised prospective study was to establish whether the use of knee splints following total knee replacement is necessary.

The study included 81 patients undergoing total knee replacement who were randomised into a ‘splint’ and a ‘no splint’ group postoperatively. Patients in the ‘splint’ group had their knee splinted in extension in the early post-operative period but the splint was removed for the patients to do exercise. Splintage was completely removed when the patient could straight leg raise. Patients in the ‘no splint’ group had a wool and crepe bandage applied around their knee and allowed to fully mobilise from the first postoperative day. The following parameters were recorded: The range of movement preoperatively, 5 days post-operatively and 6 weeks postoperatively; the length of time to straight leg raise; the blood drained from the wound. and the amount of postoperative analgesia required.

Using the unpaired 2 tailed t-test it was found that patients in the four ‘no splint’ group achieved significantly greater flexion at 5 days and 6 weeks post-operatively but drained significantly more blood from the wound. Transfusion requirements were similar in the two groups. There was no other significant difference in the parameters measured between the two groups.

In conclusion we found no evidence to advocate the use of knee splints following total knee arthroplasty.

Purpose: Posters of study: To produce a virtual reality model of prosthetic knee joint motion, giving detail regarding contact area and contact pressures during the process of walking.

Method: Using serial CT scans and data regarding the material properties of bone, cartilage, ligaments and other soft tissue structures a computational “virtual reality model” of the knee has been constructed. This computational model which is a 3D dynamic representation of a human knee joint, may be programmed to replicate the standard gait pattern of the human knee.

This study details the development of this model and its validation against the accepted Stenmore Test Rig for modelling of knee joint movement and knee prosthetic wear. The validation results will be presented,

The model allows the calculation and representation of contact pressures and contact areas in the knee joint as it moves through the gait cycle. This study also shows the effect of uni-condular loading and varus mal-positioning which may occur at surgery and the effect this has on the contact area and contact pressures of a prosthetic knee in ambulation. The resultant gait pattern produced by uni-condular loading and exhibited by the virtual knee closely resembles that seen in In Vivo Kinematic Studies reported by other authors.

In conclusion we present this as a valid computational dynamic model of knee prosthetic wear and kinematics which represents an enormous advantage over standard mechanical testing and presents possibilities for rapid analysis in new knee joint designs and the effect of abnormalities of gait and wear.

We have undertaken a prospective evaluation of health-related quality-of-life outcomes in 26 consecutive patients undergoing periacetabular osteotomy with a minimum follow-up of 24 months (24 to 42). The Western Ontario-Macmaster (WOMAC) and Short Form 36 (SF-36) outcome measures were evaluated preoperatively and at follow-up. Secondary outcome measures included retrospective assessment of sports activity and satisfaction with the procedure.

Follow-up data were available for 22 patients (85%). A significant improvement in the pain (p < 0.0001) and function (p < 0.0001) scales of the WOMAC and the SF-36 physical score (p < 0.0001) was seen. The mean sports activity score improved from 1.9 to 4.4, with a very high mean satisfaction rating of 89.7/100.

A significant improvement in both global and disease-specific health outcomes can be expected after this operation, with a high rate of satisfaction and improvement in sporting activities.

Two dimensional ultrasound of the shoulder joint has become a well established diagnostic tool. Difficult interpretation of ultrasonographic findings, however, suggests that ultrasound appears not to be an always reliable method, especially in partial thickness tears. The present study was performed to determine whether the use of three dimensional (3D) sonography further increases the diagnostic yield of ultrasound.

On a total of 22 externally intact appearing rotator cuffs of cadaveric shoulder joints 7 full thickness and 15 partial thickness incisions were carried out on the M. supraspinatus, subscapularis and infraspinatus tendon. The specimens included the humeral head, the glenoid, the joint capsule and periarticular tendons.

Ultrasound was performed on the shoulder specimens in a water basin with a 8.5 MHz curved array transducer (Combison 530D, Kretztechnik, Zipf, Austria).

With three dimensional ultrasound rotator cuff lesions were more often correctly diagnosed (sensitivity of 77 %) than with conventional 2D sonography (sensitivity of 64 %). Specificity was 85 % and 69 %, respectively. In partial thickness tears in particular, 3D imaging was the superior method reaching a sensitivity and specifity of 73% and 77%, respectively compared to 53% and 61%, respectively with 2D ultrasound.

The use of three dimensional ultrasound appears to have a higher diagnostic yield in partial thickness tears. One advantage is that the examiner must not move the transducer to obtain other planes. Changes in echogenicity can be observed in the complete volume and in any plane. In the diagnosis of partial tears these changes enabled the examiner to distinguish intact from ruptured tissue.

We have examined whether primary human muscle-derived cells can be used in ex vivo gene therapy to deliver BMP-2 and to produce bone in vivo. Two in vitro experiments and one in vivo experiment were used to determine the osteocompetence and BMP-2 secretion capacity of cells isolated from human skeletal muscle.

We isolated five different populations of primary muscle cells from human skeletal muscle in three patients. In the first in vitro experiment, production of alkaline phosphatase by the cells in response to stimulation by rhBMP-2 was measured and used as an indicator of cellular osteocompetence. In the second, secretion of BMP-2 was measured after the cell populations had been transduced by an adenovirus encoding for BMP-2. In the in vivo experiment, the cells were cotransduced with a retrovirus encoding for a nuclear localised β-galactosidase gene and an adenovirus encoding for BMP-2. The cotransduced cells were then injected into the hind limbs of severe combined immune-deficient (SCID) mice and analysed radiographically and histologically. The nuclear localised β-galactosidase gene allowed identification of the injected cells in histological specimens. In the first in vitro experiment, the five different cell populations all responded to in vitro stimulation of rhBMP-2 by producing higher levels of alkaline phosphatase when compared with non-stimulated cells. In the second, the five different cell populations were all successfully transduced by an adenovirus to express and secrete BMP-2. The cells secreted between 444 and 2551 ng of BMP-2 over three days. In the in vivo experiment, injection of the transduced cells into the hind-limb musculature of SCID mice resulted in the formation of ectopic bone at 1, 2, 3 and 4 weeks after injection. Retroviral labelling of the cell nuclei showed labelled human muscle-derived cells occupying locations of osteoblasts in the ectopic bone, further supporting their osteocompetence.

Cells from human skeletal muscle, because of their availability to orthopaedic surgeons, their osteocompetence, and their ability to express BMP-2 after genetic engineering, are an attractive cell population for use in BMP-2 gene therapy approaches.

We present a study of ten consecutive patients who underwent excision of thoracic or thoracolumbar hemivertebrae for either angular deformity in the coronal plane, or both coronal and sagittal deformity. Vertebral excision was carried out anteriorly alone in two patients. Seven patients had undergone previous posterior spinal fusion. Their mean age at surgery was 13.4 years (6 to 19). The mean follow-up was 78.5 months (20 to 180). The results were evaluated by radiological review of the preoperative, postoperative and most recent follow-up films.

The mean preoperative coronal curve was 78.2° (30 to 115) and was corrected to 33.9° (7 to 58) postoperatively, a mean correction of 59%. Preoperative coronal decompensation of 35 mm was improved to 11 mm postoperatively. Seven patients had significant coronal decompensation preoperatively, which was corrected to a physiological range postoperatively. There were no major complications and no neurological damage.

We have shown that resection of thoracic and thoracolumbar hemivertebrae can be performed safely, without undue risk of neurological compromise, in experienced hands.

The pathogenesis of aseptic loosening of total joint prostheses is not clearly understood. Two features are associated with loosened prostheses, namely, particulate debris and movement of the implant. While numerous studies have evaluated the cellular response to particulate biomaterials, few have investigated the influence of movement of the implant on the biological response to particles. Our aim was therefore to test the hypothesis that excessive mechanical stimulation of the periprosthetic tissues induces an inflammatory response and that the addition of particulate biomaterials intensifies this.

We allocated 66 adult Beagle dogs to four groups as follows: stable implants with (I) and without (II) particulate polymethylmethacrylate (PMMA) and moving implants with (III) and without (IV) particulate PMMA. They were then evaluated at 2, 4, 6, 12 and 24 weeks.

The stable implants were well tolerated and a thin, fibrous membrane of connective tissue was observed. There was evidence of positive staining in some cells for interleukin-6 (IL-6). Addition of particulate PMMA around the stable implants resulted in an increase in the fibroblastic response and positive staining for IL-6 and tumour necrosis factor-alpha (TNF-α). By contrast, movement of the implant resulted in an immediate inflammatory response characterised by large numbers of histiocytes and cytokine staining for IL-1ß, TNF-α and IL-6. Introduction of particulate PMMA aggravated this response. Animals with particulate PMMA and movement of the implant have an intense inflammatory response associated with accelerated bone loss.

Our results indicate that the initiation of the inflammatory response to biomaterial particles was much slower than that to gross mechanical instability. Furthermore, when there was both particulate debris and movement, there was an amplification of the adverse tissue response as evidenced by the presence of osteolysis and increases in the presence of inflammatory cells and their associated cytokines.

Caveolae, specialised regions of the cell membrane which have been detected in a wide range of mammalian cells, have not been described in bone cells. They are plasmalemmal invaginations, 50 to 100 nm in size, characterised by the presence of the structural protein, caveolin, which exists as three subtypes. Caveolin-1 and caveolin-2 are expressed in a wide range of cell types whereas caveolin-3 is thought to be a muscle-specific subtype. There is little information on the precise function of caveolae, but it has been proposed that they play an important role in signal transduction.

As the principal bone-producing cell, the osteoblast has been widely studied in an effort to understand the signalling pathways by which it responds to extracellular stimuli. Our aim in this study was to identify caveolae and their structural protein caveolin in normal human osteoblasts, and to determine which subtypes of caveolin were present. Confocal microscopy showed staining which was associated with the plasma membrane. Transmission electron microscopy revealed the presence of membrane invaginations of 50 to 100 nm, consistent with the appearance of caveolae. Finally, we isolated protein from these osteoblasts, and performed Western blotting using anti-caveolin primary antibodies. This revealed the presence of caveolin-1 and -2, while caveolin-3 was absent.

The identification of these structures and their associated protein may provide a significant contribution to our further understanding of signal transduction pathways in osteoblasts.

We studied the effect of the surface finish of the stem on the transfer of load in the proximal femur in a sheep model of cemented hip arthroplasty. Strain-gauge analysis and corresponding finite-element (FE) analysis were performed to assess the effect of friction and creep at the cement-stem interface.

No difference was seen between the matt and polished stems. FE analysis showed that the effects of cement creep and friction at the stem-cement interface on femoral strain were small compared with the effect of inserting a cemented stem.

There are few medium- and long-term data on the outcome of the use of proximal femoral structural allografts in revision hip arthroplasty. This is a study of a consecutive series of 40 proximal femoral allografts performed for failed total hip replacements using the same technique with a minimum follow-up of five years (mean 8.8 years; range 5 to 11.5 years). In all cases the stem was cemented into both the allograft and the host femur. The proximal femur of the host was resected in 37 cases.

There were four early revisions (10%), two for infection, one for nonunion of the allograft-host junction, and one for allograft resorption noted at the time of revision of a failed acetabular reconstruction. Junctional nonunion was seen in three patients (8%), two of whom were managed successfully by bone grafting, and bone grafting and plating respectively. Instability was observed in four (10%). Trochanteric nonunion was seen in 18 patients (46%) and trochanteric escape in ten of these (27%). The mean Harris hip score improved from 39 to 79. Severe resorption involving the full thickness of the allograft was seen in seven patients (17.5%). This progressed rapidly and silently, but has yet to cause failure of any of the reconstructions.

Profound resorption of the allograft may be related to a combination of factors, including a slow form of immune rejection, stress shielding and resorption due to mechanical disuse with solid cemented distal fixation, and the absence of any masking or protective effect which may be provided by the retention of the bivalved host bone as a vascularised onlay autograft. Although continued surveillance is warranted, the very good medium-term clinical results justify the continued use of structural allografts for failed total hip replacements with severe loss of proximal femoral bone.

We have previously described a simple and reproducible three-dimensional technique of CT for the measurement of the cover of the femoral head in acetabular dysplasia in adults. We now describe the application of this technique in ten patients with symptomatic dysplasia to assess the degree and direction of dysplasia and to measure the cover obtained at acetabular osteotomy.

The indices obtained gave a useful indication of the degree and direction of the dysplasia and confirmed which components had been used most efficiently to achieve cover. The information is easily presented in graphical form and gives a clearer indication of the cover obtained than the indices derived from plain radiographs.