Introduction

Weight is a modifiable risk factor for osteoarthritis (OA) progression. Despite the emphasis on weight loss, data quantifying the changes seen in joint biomechanics are limited. Bariatric surgery patients experience rapid weight loss. This provides a suitable population to study changes in joint forces and function as weight changes.

Introduction

Many patients with obesity experience knee pain. Excess body weight is a modifiable risk factor for osteoarthritis (OA) and weight loss is encouraged in patients with OA. Bariatric surgery could improve or limit the progression of these conditions through significant weight loss. The Oxford Knee Score (OKS) is a validated tool in the assessment of knee replacement surgery for OA. We present a novel application of the OKS to assess knee pain & function after weight loss surgery. The primary aim of this study was to assess whether there was a significant difference in mean OKS before and 24 months after weight loss surgery.

Abstract

Introduction

Nucleus replacement surgery has the potential to be an early treatment option for chronic lower back pain. The surgery involves removal (nuclectomy) and replacement of the native degenerated nucleus with a material designed to restore the disc's physiological properties. Multiple techniques have been considered to perform a nuclectomy, however the advantages and disadvantages of each are not well understood. The aim of this study was to quantitatively compare three nuclectomy techniques: automated-shaver, rongeurs, and laser.

Aims

Day-case arthroplasty is gaining popularity in Europe. We report outcomes from the first 12 months following implementation of a day-case pathway for unicompartmental knee arthroplasty (UKA) and total hip arthroplasty (THA) in an NHS hospital.

Purpose

Back pain is the primary cause of disability worldwide yet surprisingly little is known of the underlying pathobiology. We conducted a genome-wide association study (GWAS) meta-analysis of chronic back pain (CBP). Adults of European ancestry from 15 cohorts in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, and UK Biobank were studied.

We reviewed all patients that suffered a deep infection following anterior cruciate ligament (ACL) repair kept between January 2007 and April 2011 at our teaching hospital NHS trust, and the two local private hospitals.

18 patients were identified. All patients underwent at least 2 arthroscopic washouts, with limited synovectomy if required. Targeted antibiotics were commenced according to the culture results, and following microbiological advice. These patients were reviewed at a minimum of 1 year following eradication of infection (range 12–46 months). There were 7 surgeons performing the ACL reconstructions.

The primary outcome measure was graft failure requiring revision. Our secondary outcome measures were a history of ongoing instability, KT 1000™ measurement, Tegner and Lysholm outcome scores. There were 18 patients identified as having suffered infection after ACL infection (mean age 24.3 years, range 15–38 years). Average C Reactive Protein (CRP) was 217 on admission (range 59–397). The most common organism isolated was coagulase negative staphylococcus in 47.3% of cases. There were 3 graft failures within the infection group. Of the remaining 15 patients there were no episodes of ongoing instability and mean pivot shift grade was 1.1, mean KT 1000™ side-to- side difference was +1.8mm. There was a reported drop on the Tegner activity score of 1.75 (range 0–6) and mean Lysholm score was 89 (range 56–100).

The failure rate is slightly higher than that reported in the literature. Patient reported outcome measures in the patients are broadly consistent. We recommend an aggressive approach to the treatment of deep infection following ACL reconstruction, in order to achieve a satisfactory outcome.

Informed consent is vital for good patient-surgeon communication. It allows the patient to be given an unbiased and accurate view of the procedure as well giving an opportunity for patients to gain trust in their surgical team. The consent form is written evidence of this discussion and a poor consent form implies a sub-standard consenting process. The General Medical Council (GMC) have issued guidelines for consent in surgical procedures. These state that all common risks and rare but serious risks should be disclosed as well as all information being given in clear simple and consistent language.

Currently, the consent form for a hip fracture operation is hand written. Our hypothesis was that the quality of consenting is variable and that many important complications may not be identified.

The British Orthopaedic Association (BOA) blue book, ‘The care of patients with fragility fractures,’ has given guidance of common and serious complications associated with operative management of hip fractures. In addition to these procedure specific complications, we have identified general complications from standardised joint arthroplasty consent forms in our trust, such as deep vein thrombosis. Our standards based on GMC guidance are that the consent form should be legible, free from jargon, without abbreviations and should include the specific and general complications.

We retrospectively identified and analysed 30 consecutive consent forms of patients that underwent operative management for hip fractures between March and April 2011. Of all consent forms, 59% were completely or partly illegible, 77% had used abbreviations and medical jargon. Inclusion of general complications on the consent form varied; infection 100%, bleeding 100%, deep vein thrombosis 82%, MI 18%, pneumonia 12%, death 12% and haematoma 0%. Specific operative complications were poorly included, with no patients undergoing hemiarthroplasty being advised of the risk of prosthetic loosening, acetabular wear or periprosthetic fractures. For consent of patients undergoing fracture fixation, 67% had been informed of re-operation and 40% had been told of non-union.

This data shows that consent forms are generally poorly written and subject to great variation in complications for the same surgical procedure. This data is likely to apply to some extent to all hospitals that use blank consent forms. This has implications for patient care and safety, as well as medicolegal implications for medical professionals. In our hospital, consent forms have been standardised for joint arthroplasty, with all complication pre-printed with plain English explanations below. Our proposal is that all common operations should have pre-printed consent forms. This would standardise consenting and provide a much improved documentary evidence of the consenting process.

This data has a number of lessons that can be applied to other hospitals. Firstly, we suggest that other hospitals consider standardised consent forms. Secondly, individual trainees should be clear that consent forms remain the documentary evidence of the consenting process, long after you forget the verbal details and you should ensure that you include all complications, write clearly and without jargon or abbreviations.

The aims of this study were (1) to assess whether rotational stability testing in Gartland III supracondylar fractures can be used intra-operatively in order to assess fracture stability following fixation with lateral-entry wires and (2) to quantify the incidence of rotational instability following lateral-entry wire fixation in Gartland type III supracondylar humeral fractures in children.

Twenty-one consecutive patients admitted with Grade III supracondylar fractures at the Children's Hospital at Westmead were surgically treated according to a predetermined protocol. Following closed fracture reduction, 2 lateral-entry wires were inserted under radiographic control. Stability was then assessed by comparing lateral x-ray images in internal and external rotation. If the fracture was found to be rotationally unstable by the operating surgeon, a third lateral-entry wire was inserted and images repeated. A medial wire was used only if instability was demonstrated after the insertion of three lateral wires.

Rotational stability was achieved with two lateral-entry wires in 6 cases, three lateral-entry wires in 10 cases and with an additional medial wire in 5 cases. Our results were compared to a control group of 24 patients treated at our hospital prior to introduction of this protocol. No patients returned to theatre following introduction of our protocol as opposed to 6 patients in the control group. On analysis of radiographs, the protocol resulted in significantly less fracture position loss as evidenced by change in Baumann's angle (p<0.05) and lateral rotational percentage (p<0.05).

We conclude that the introduction of rotational stability testing allows intra-operative assessment of fracture fixation. Supracondylar fractures that are rotationally stable intra-operatively following wire fixation are unlikely to displace post-operatively. Only a small proportion (26%) of these fractures were rotationally stable with 2 lateral-entry wires. This may be a reflection of either the fracture configuration or inability to adequately engage the medial column.

Hypothesis

Recent advances in understanding of ACL insertional anatomy has led to new concepts of anatomical positioning of tunnels for ACL reconstruction. Femoral tunnel position has been defined in terms of the lateral intercondylar ridge and the bifurcate ridge but these can be difficult to identify at surgery. Measurements of the lateral wall either using C-arm x-ray control or specific arthroscopic rulers have also been advocated.

Introduction

There are numerous surgical techniques for medial patellofemoral ligament (MPFL) reconstruction. Problems with certain techniques include patellar fracture and re-rupture.

Introduction

Current problem – Multiple surgical interventions for patellar instability and no defined criteria for use of medial patellofemoral ligament (MPFL) reconstruction.

An experimental sheep model was used for impaction allografting of 12 hemiarthroplasty femoral components placed into two equal-sized groups. In group 1, a 50:50 mixture of ApaPore hydroxyapatite bone-graft substitute and allograft was used. In group 2, ApaPore and allograft were mixed in a 90:10 ratio. Both groups were killed at six months. Ground reaction force results demonstrated no significant differences (p > 0.05) between the two groups at 8, 16 and 24 weeks post-operatively, and all animals remained active. The mean bone turnover rates were significantly greater in group 1, at 0.00206 mm/day, compared to group 2 at 0.0013 mm/day (p < 0.05). The results for the area of new bone formation demonstrated no significant differences (p > 0.05) between the two groups. No significant differences were found between the two groups in thickness of the cement mantle (p > 0.05) and percentage ApaPore-bone contact (p > 0.05).

The results of this animal study demonstrated that a mixture of ApaPore allograft in a 90:10 ratio was comparable to using a 50:50 mixture.

Introduction Bone graft supply for impaction grafting can be problematic due to the supply of graft, sterilisation, which alters the biological properties of the graft, and the immunogencity of the graft which may lead to graft rejection. Reducing the amount of graft can be accomplished by using increased amounts of synthetic materials such as hydroxyapatite (HA). This study evaluated the effect of using mixtures of porous HA (Apapore™) with allograft for cemented impaction allografting of the femoral stem in an ovine model. The aim was to test the hypothesis that increased quantities of Apapore™ will be stable and induce similar bone remodelling to that where a 50:50 mixture with allograft was used.

Method Twelve hemi-arthroplasty femoral components were inserted into the right hip of skeletally mature female commercially cross-bred sheep weighing between 65 and 80kg. Femoral components were manufactured from Cobalt Chromium alloy and cemented in place following impaction of the femoral canal. Animals were randomly placed into one of two groups according to the allograft-apapore mixture used. Group 1: Apapore:allograft mixed 50:50. Group 2: Apapore: allograft mixed 90:10. Six animals were investigated in each group. Implants remained in vivo for 6 months. In order to quantify bone formation rates, oxytetracycline injections were given 2 months post-surgery and 3 weeks later, followed by a third administration in the fifth month post-surgery and 3 weeks later. Animals were walked over a force plate pre-operatively and at 8, 16 and 24 weeks post-operatively. Twelve readings of maximum force (Fmax, N/m2) were taken and average values of right over left were calculated as a percentage (%AR/AL) and represented how well the animal used its operated leg where 100% represents full weight-bearing. Thin sections (~70μm thick) were prepared through four regions of the femur. The proximal, mid and tip of the femoral component region and one distal to the implant tip were analysed where bone area, Apapore™ area, Apapore™-bone contact and cement mantle thickness were quantified and compared using image analysis techniques.

Results In both groups, the use of graft resulted in the formation of a cancellous network of bone on the endosteal surface which incorporated the Apapore™ granules. When all regions were compared, femoral bone turnover results demonstrated significantly increased rates in group 1 (0.0021mm day-1) when compared with group 2 (0.0015mm day-1) (p< 0.05). No significant differences were identified when the proximal, mid and tip regions in the two groups were compared however, significantly increased turnover was identified in the distal region in group 1 (0.0027 mm day-1) when compared with group 2 (0.0013mm day-1) (p< 0.05). In both groups increased turnover was observed in the proximal, tip and distal regions with least in the mid region of the stem. Ground Reaction Force (GRF) results demonstrated no significant differences between the two experimental groups at 8, 16 and 24 weeks postoperatively. In both groups, a significant decline in function was demonstrated 8 weeks post-op when compared with pre-operative values and in both groups function gradually increased over time. Results for new bone area demonstrated significantly increased new bone in the proximal and distal regions in both groups (proximal =7.94mm2 and 7.13mm2; distal =7.03mm2 and 8.17mm2, group 1 and 2 respectively) with least new bone in the mid region of the stem (4.53mm2 and 4.79mm2). No significant differences in any of the regions were demonstrated when group 1 and 2 were compared. In both groups, significantly increased amounts of Apapore™ was observed in the proximal and distal regions of the femoral stem with least in the mid and tip region. No significant difference in cement mantle thickness was identified between the two groups.

Discussion Results demonstrated that hips maintained functional stability when a higher amount of Apapore™ mixture was used. Results for bone turnover rates and the amount of new bone formation in the 90:10 mixture demonstrated Apapore™ to be a comparable and suitable alternative to replace allograft in impaction grafting of a femoral component.

Introduction: ApaPore is a synthetic bone graft extender, made from Hydroxyapatite. It is designed to be used as a 50:50 combination by volume with morcelised bone graft. A typical use for such a product may be in impaction allografting during revision hip surgery. The aim of this study was to compare the mechanical stability of stems inserted using impaction allografting where the graft was composed of a 50:50 mixture of ApaPore and allograft with only allograft.

Methods: Twelve large left sawbones were used in this study, the femoral head was cut off each one and the equivalent cancellous bone was cored out to resemble a femur at revision. Impaction allograft was performed on six of the sawbones, with rinsed human morsellised graft. This procedure was repeated on the remaining six sawbones, with graft produced as a 50:50 mixture by volume of rinsed allograft and blood soaked Apapore. The mechanical test was performed in the red rocket, a six station hydraulic loading machine. The sawbones were mounted in the anatomical position of 7 degrees valgus and 9 degrees posteriorly and the test was run in batches of three. Sinusoidal loading at 2Hz was applied under the following loads: 600N, 1kN, 1.4kN, 1.8kN and 2.2kN, each loading step lasting for 5000 cycles. Migration of the stem during loading was measured using LVDT. Vertical displacement of the prosthesis head was measured using digital height callipers at the beginning and end of each loading step. X-Rays were taken before and after mechanical testing.

Results: There is a significant difference between the groups in the overall displacement of the prosthesis head, measured with the digital height calipers, (Mann-Whitney U Test p=0.01). Total average head movement allograft group: 3.5mm and ApaPore group: 1.8mm. The total average subsidence measured with the LVDT’s was 0.295 mm in the allograft group and 0.119mm in the ApaPore/Allograft group. A sideways displacement of the prosthesis head was observed on the x-rays, which is a direct relationship of head rotation, measurements showed a significantly less rotation in the ApaPore/Allograft group (Mann-Whitney U Test p=0.002).

Conclusions: Rotation of the stem in all planes during loading resulted in a greater observed displacement of the prosthesis head than that measured by the LVDT’s. These results show that ApaPore, when used as a bone graft extender is able to reduce initial rotation and subsidence of the stem. Further research needs to be undertaken to investigate the long-term feasibility of using ApaPore.

Introduction and Aims: Union of femoral shaft fractures in a shortened position is a recognised complication of spica cast treatment. Such shortening can only be assessed radiographically until the spica has been removed. The constraints of a spica cast complicate the imaging of the femur and may lead to error in assessing shortening. This study aims to quantify the magnitude of such error for application to clinical practice.

Method: A model for a spiral femoral fracture in a spica cast was devised. Shortening of the femoral segment through telescoping and angulation was controlled with a Wagner lengthening device external to the spica. Shortening from angulation and telescoping were varied and radiographic measurements compared with real measurements. The correlation between true and radiographic shortening of > 2cm was measured with the kappa value.

Results: There was good agreement between radiological and real shortening of > 2cm. Where shortening was present without angulation, the radiological measurement over-estimated the degree of shortening. The error increased with the amount of shortening. Angulation of more than 30 degrees caused the radiological measurement to under-estimate the true amount of segmental shortening.

Conclusion: This study suggests that radiological measurement of femoral shortening in a spica should reliably predict clinically significant shortening when there is less than 30 degrees of fracture angulation.

Introduction and Aims: An important prognostic factor in neonatal brachial plexus injury is the timing of biceps recovery. Although the natural history is not clear, biceps recovery after three months has been used to predict universally poor long-term shoulder function. The absence of biceps function at three months has been adopted as an indication for early microsurgery, in an attempt to improve upper limb function. e

Method: Between 1980 and 1992, 170 patients with neonatal brachial plexus injury were entered into a prospective study, which recorded details of the birth and serial examinations. Patients were grouped according to the level of injury and timing of biceps return. Twenty-nine patients were observed to have absent biceps at three months. Twenty-eight of 29 patients were available for long-term review at an average of 11 years and one month (range 5yrs 7mths–16 years). At follow-up, patients answered a questionnaire, underwent muscle strength testing, sensory evaluation, and had their shoulder function graded according to Gilbert’s modification of the Mallet score. The level of injury and time of biceps return were compared to the final outcomes.

Results: The level of injury was C5/6 in 13/28 (46%), C5/6/7 in 5/28 (18%) and pan-plexus in 10/28 (36%), with a Horner’s syndrome in four patients. Of the 28 patients with absent biceps function at three months, biceps contraction was observed in 20 patients (71%) by six months. 13/13 C-5,6 patients, 3/5 C-5,6,7 patients, and 4/9 pan-plexus patients (0/4 of those with a Horner’s syndrome) regained biceps by six months. Twenty-two patients did not have plexus surgery, nine of these had subsequent shoulder surgery. At follow-up, 27 of 28 patients had at least anti-gravity biceps function. Patients who regained biceps function between three and six month had better scores for abduction (p=0.04), hand to neck (p=0.05) and hand to back (p< 0.001) than patients who regained biceps after six months. Patients with C-5, 6 lesions had better scores for external rotation (p=0.04), hand to neck (p=0.05), hand to mouth (p< 0.01) and hand to back (p< 0.001) than patients with pan-plexus lesions. Twelve of the 22 (55%) patients who did not have plexus surgery had Mallet class IV shoulders (good function). Of the C-5, 6 patients who did not have plexus surgery, 8/12 had class IV shoulders.

Conclusion: This study supports the associations between prolonged neurological recovery, more extensive level of injury and worse long-term shoulder function. In patients with C-5, 6 injuries and absent biceps function at three months, good shoulder function is common in the long-term without plexus surgery. This finding is important in considering the indications for and the results of early microsurgical intervention.

This study investigates the use of porous biphasic ceramics as graft extenders in impaction grafting of the femur during revision hip surgery.

Impaction grafting of the femur was performed in four groups of sheep. Group one received pure allograft, group two 50% allograft and 50% BoneSave, group three 50% allograft and 50% BoneSave type 2 and group four 10% allograft and 90% BoneSave as the graft material. Function was assessed using an index of pre- and post-operative peak vertical ground reaction force ratios. Changes in bone mineral density were measured by dual energy X ray absorptiometry (DEXA) scanning. Loosening and subsidence were assessed radiographically and by histological examination of the explanted specimens.

There was no statistically significant difference between the four groups after 18 months of unrestricted functional loading for all outcome measures.

Introduction Bilateral total knee replacement under one anaesthetic is a common procedure. Claimed benefits include: shorter hospital stays, fewer complications of some kinds, lower over all cost and more efficient use of staff time. In general the literature supports these concepts though some writers caution against the procedure. Most studies come from large university hospitals but most joint replacements are done in smaller hospitals. At Calvary Hospital we instituted a quality assessment review of our experience to determine patient safety and cost savings.

Methods A medical records review between 1997 and 2001 showed 63 patients had bilateral total knee replacement (126 knees). We further identified 38 patients who had both knees replaced at separate admissions within one year (76 knees), these were the staged knee replacements. We selected a matched subset of the patients who had only one joint replaced in this period (125 knees). A review was carried out over a wide variety of parameters on a relation database.

Results The incidence of infection, unplanned return to theatre and DVT was too low for this study to have statistical power and little difference was noted. Amongst the more common post-operative respiratory, cardiovascular and gastrointestinal complications no significant difference was noted per hospital admission. Post-operative confusion was not more common in bilateral replacements and we felt that fat embolism syndrome was not increased. Neither, type of anaesthesia, previous medical history nor post-operative care predicted for confusion but we did note a strikingly increased incidence in patients of low BMI. Contrary to common views obese patients did not have more complications or longer hospital stays. Mobilisation in heavy patients is not prolonged provided they have good upper limb strength. Blood transfusion is more likely in bilateral cases but our review has allowed us to formulate a nomogram based on weight and pre-operative haemoglobin to improve blood management. High admission rates to ICU were noted but mostly for precautionary reasons, the unplanned admission rate was not greater. Pre-operative urinary tract infection and use of an IDC were not associated with any infective events.

Conclusions Bilateral total knee replacement was found to be a safe proceedure with complication rates equivalent to single knee replacement. For the patient who has severe arthritis in both knees it is prefered to repeated single knee replacement as the exposure to complications is halved. A nomogram to predict blood transfusion requirements has allowed a reduction in the transfusion rate for all groups. Twenty-three hour recovery admission covers the needs of bilateral replacement patients in the immediate post-opertaive setting. Cost savings are identified allowing four knees to be replaced, if done bilaterally, for each three knees replaced as seperate admissions.

Objective: Recent reports have suggested a low incidence of neurological complications following anterior deformity surgery; however in patients with co-existing intra-spinal anomalies no quantification of this risk has been made. Also, whether SSEP monitoring and soft clamping of segmental vessels prior to their division is necessary for these anterior procedures is controversial.

The aims of this study were to determine the incidence of significant SSEP changes in patients undergoing anterior spinal deformity surgery; to ascertain whether the ‘at risk’ cord was more likely to demonstrate significant intraoperative SSEP changes and what proportion of these changes yielded post operative neurological deficit.

Design: Retrospective analysis of operative notes and somatosensory evoked potential (SSEP) traces of patients who underwent anterior spinal deformity surgery between 1990–2001.

Subjects: All patients who underwent anterior spinal deformity surgery between 1990–2001, who had complete data sets (preoperative MRI scan, patient and procedural documentation and intraoperative SSEP traces) were included in the study.

Outcome measures: All post operative neurological deficits and significant SSEP changes were noted, whether or not patients had a ‘cord at risk’.

Results: In total, 871 patients had elective anterior spinal deformity surgery. Preoperative MRI revealed 95 patients (11%) demonstrated intraspinal anomalies on MRI but of these only 27 showed abnormal pre-operative SSEP i.e. cord at risk (CAR). Seventeen (2% of total) of this group developed abnormal intraoperative SSEP responses and ten (1.3%) occurred in the normal group. The incidence of post-operative paraparesis for the whole series was 0.6% (n=5): four in the CAR group, one in the normal cord group. Sensitivity of SSEPs in detecting potential neurological deficit was 100%; specificity 98.6%, positive predictive value 29.4% and negative predictive value 100%. Significant intraoperative SSEP changes occurred more frequently in the CAR group and were more likely to have post operative paraparesis.

Conclusions: SSEP monitoring is a sensitive and specific test, which in experienced hands yields no false positive results. Spinal cord monitoring and soft clamping of segmental vessels should be performed in patients with CAR undergoing anterior spinal deformity surgery to minimise the risk of post operative paraparesis.