Aims

The primary aim of this trial was to compare the subsidence of two similar hydroxyapatite-coated titanium femoral components from different manufacturers. Secondary aims were to compare rotational migration (anteversion/retroversion and varus/valgus tilt) and patient-reported outcome measures between both femoral components.

Aims

To evaluate if, for orthopaedic trainees, additional cadaveric simulation training or standard training alone yields superior radiological and clinical outcomes in patients undergoing dynamic hip screw (DHS) fixation or hemiarthroplasty for hip fracture.

Aims

Ankle fracture fixation is commonly performed by junior trainees. Simulation training using cadavers may shorten the learning curve and result in a technically superior surgical performance.

Cup-cage constructs are one of several methods commonly used to treat severe acetabular bone loss during contemporary revision total hip arthroplasty. The purpose of this study was to provide a long-term results of the technique with emphasis on implant survivorship, radiographic results, and clinical outcomes for both full and half cup-cage reconstructions.

We identified 57 patients treated with a cup-cage reconstruction for major acetabular bone loss between 2002–2012. All patients had Paprosky Type 2B through 3B bone loss, with 60% having an associated pelvic discontinuity. Thirty-one patients received a full cup-cage construct, and 26 a half cup-cage. Mean age at reconstruction was 66 years, 75% were female, and the mean BMI was 27 kg/m². Mean follow-up was 10 years.

The 10-year cumulative incidences of any revision were 14% and 12% for the full and half cup-cage construct groups, respectively. Of the 9 revisions, 3 were for dislocation, 2 for aseptic loosening and construct failure (both were pelvic discontinuities), 1 for adverse local tissue reaction, and 1 for infection with persistent pelvic discontinuity. The 10-year cumulative incidences of revision for aseptic loosening were 4.5% and 5% for the full and half cup-cage constructs, respectively. Of the unrevised cases, incomplete and non-progressive zone 3 radiolucent lines were observed in 10% of patients in each group. Three patients experienced partial motor and sensory sciatic nerve palsies (2 in the full and 1 in the half cup-cage group). Both the full and half cup-cage cohorts demonstrated significantly improved Harris hip scores.

Full and half cup-cage reconstructions for major acetabular defects were successful at 10 years in regards to acetabular fixation without appreciable differences between the two techniques. However, zone 3 radiolucent lines were not uncommon in association with discontinuities, and dislocation continues to be a problem.

Aims

Nonagenarians (aged 90 to 99 years) have experienced the fastest percent decile population growth in the USA recently, with a consequent increase in the prevalence of nonagenarians living with joint arthroplasties. As such, the number of revision total hip arthroplasties (THAs) and total knee arthroplasties (TKAs) in nonagenarians is expected to increase. We aimed to determine the mortality rate, implant survivorship, and complications of nonagenarians undergoing aseptic revision THAs and revision TKAs.

Aims

Knowledge on total knee arthroplasties (TKAs) in patients with a history of poliomyelitis is limited. This study compared implant survivorship and clinical outcomes among affected and unaffected limbs in patients with sequelae of poliomyelitis undergoing TKAs.

Aims

Instability is a common cause of failure after total hip arthroplasty. A novel reverse total hip has been developed, with a femoral cup and acetabular ball, creating enhanced mechanical stability. The purpose of this study was to assess the implant fixation using radiostereometric analysis (RSA), and the clinical safety and efficacy of this novel design.

Aims

The aim of this study was to assess the accuracy of pedicle screw placement, as well as intraoperative factors, radiation exposure, and complication rates in adult patients with degenerative disorders of the thoracic and lumbar spines who have undergone robotic-navigated spinal surgery using a contemporary system.

Aims

Spinal anaesthesia has seen increased use in contemporary primary total knee arthroplasties (TKAs). However, controversy exists about the benefits of spinal in comparison to general anaesthesia in primary TKAs. This study aimed to investigate the pain control, length of stay (LOS), and complications associated with spinal versus general anaesthesia in primary TKAs from a single, high-volume academic centre.

Aims

Septic arthritis of the hip often leads to irreversible osteoarthritis (OA) and the requirement for total hip arthroplasty (THA). The aim of this study was to report the mid-term risk of any infection, periprosthetic joint infection (PJI), aseptic revision, and reoperation in patients with a past history of septic arthritis who underwent THA, compared with a control group of patients who underwent THA for OA.

Aims

Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and acetabular rim in positions of hip flexion combined with rotation is a proposed pathomechanism in these hips, but this has not been studied in active postures. Our aim was to assess the anterior impingement pathomechanism in both active and passive postures with high hip flexion that are thought to provoke impingement.

Aims

Anterior cruciate ligament (ACL) rupture commonly leads to post-traumatic osteoarthritis, regardless of surgical reconstruction. This study uses standing MRI to investigate changes in contact area, contact centroid location, and tibiofemoral alignment between ACL-injured knees and healthy controls, to examine the effect of ACL reconstruction on these parameters.

Aims

A multicentre, randomized, clinician-led, pragmatic, parallel-group orthopaedic trial of two surgical procedures was set up to obtain high-quality evidence of effectiveness. However, the trial faced recruitment challenges and struggled to maintain recruitment rates over 30%, although this is not unusual for surgical trials. We conducted a qualitative study with the aim of gathering information about recruitment practices to identify barriers to patient consent and participation to an orthopaedic trial.

Aims

The aim of this study was to determine the diagnostic accuracy of α defensin (AD) lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) tests for periprosthetic joint infection (PJI) in comparison to conventional synovial white blood cell (WBC) count and polymorphonuclear neutrophil percentage (PMN%) analysis.

Aims

It remains difficult to diagnose early postoperative periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). We aimed to validate the optimal cutoff values of ESR, CRP, and synovial fluid analysis for detecting early postoperative PJI in a large series of primary TKAs.

Aims

We report the long-term outcomes of the UK Heel Fracture Trial (HeFT), a pragmatic, multicentre, two-arm, assessor-blinded, randomized controlled trial.

Introduction

Septic arthritis of the native knee often results in irreversible joint damage leading to the need for a total knee arthroplasty (TKA). This study examines the mid-term risk of periprosthetic joint infection (PJI), aseptic revision, any revision, and any reoperation in primary TKAs after septic arthritis of the native knee compared to a control cohort of primary TKAs performed for osteoarthritis (OA).

Introduction

Instability remains a common complication following total hip arthroplasty (THA) and continues to account for the highest percentage of revisions in numerous registries. Many risk factors have been described, yet a patient-specific risk assessment tool remains elusive. The purpose of this study was to apply a machine learning algorithm to develop a patient-specific risk score capable of dynamic adjustment based on operative decisions.

Aims

To develop a core outcome set of measurements from postoperative radiographs that can be used to assess technical skill in performing dynamic hip screw (DHS) and hemiarthroplasty, and to validate these against Van der Vleuten’s criteria for effective assessment.

Aims

The primary aim of the survey was to map the current provision of simulation training within UK and Republic of Ireland (RoI) trauma and orthopaedic (T&O) specialist training programmes to inform future design of a simulation based-curriculum. The secondary aims were to characterize; the types of simulation offered to trainees by stage of training, the sources of funding for simulation, the barriers to providing simulation in training, and to measure current research activity assessing the educational impact of simulation.

Aims

We evaluated a large database with mechanical failure of a single uncemented modular femoral component, used in revision hip arthroplasty, as the end point and compared them to a control group treated with the same implant. Patient- and implant-specific risk factors for implant failure were analyzed.

Aims

There is little information regarding the risk of a patient developing prosthetic joint infection (PJI) after primary total knee arthroplasty (TKA) when the patient has previously experienced PJI of a TKA or total hip arthroplasty (THA) in another joint. The goal of this study was to compare the risk of PJI of primary TKA in this patient population against matched controls.

Aims

The aims of this study were to characterize antibiotic choices for perioperative total knee arthroplasty (TKA) and total hip arthroplasty (THA) prophylaxis, assess antibiotic allergy testing efficacy, and determine rates of prosthetic joint infection (PJI) based on perioperative antibiotic regimen.

Objectives

Platelet-rich plasma (PRP) is being used increasingly often in the clinical setting to treat tendon-related pathologies. Yet the optimal PRP preparations to promote tendon healing in different patient populations are poorly defined. Here, we sought to determine whether increasing the concentration of platelet-derived proteins within a derivative of PRP, platelet lysate (PL), enhances tenocyte proliferation and migration in vitro, and whether the mitogenic properties of PL change with donor age.

Introduction

First generation cephalosporins remain the gold standard perioperative antibiotic for total hip and knee arthroplasty (THA, TKA). However, some patients have documented or self-reported allergies to antibiotics, most commonly penicillin, that result in changes to perioperative antibiotic coverage. Furthermore, patients testing positive for methicillin resistant staphylococcus aureus (MRSA) represent another group where an alternative to cefazolin, typically vancomycin, is often chosen for perioperative prophylaxis. The aims of this study were to 1) characterize the antibiotic choices for perioperative prophylaxis at the time of primary TKA and THA, 2) assess the efficacy of a preoperative antibiotic allergy testing program, and 3) determine rates of periprosthetic joint infection (PJI) based on perioperative antibiotic regimen.

Introduction

There is no literature regarding the risk of a patient developing PJI after primary TKA if the patient has previously experienced PJI of a TKA or THA in another joint. The goal of this study was to compare the risk of PJI of primary TKA in this patient population compared to matched controls.

Introduction

Two-stage revision surgery remains the gold standard as treatment for periprosthetic hip infections. The purpose of this study was to determine the rate of infection eradication after two-stage revision hip arthroplasty in patients treated with intraoperatively surgeon-molded articulating spacers as well as to foreshadow the future economical impact of these articulating antibiotic spacers to those commercially available.

Aims

Using 90% of final height as a benchmark, we sought to develop a quick, quantitative and reproducible method of estimating skeletal maturity based on topographical changes in the distal femoral physis.

A longitudinal study was done assessing the latest radiographs available in a series of collarless Corail uncemented stems which have reported survival rates of 95% at 20 years. Parameters scored included the degree of “Ghosting” or delamination, the Gruen, the stem fit in the femoral canal and the degree of calcar resorption. Patient and implant demographics were noted.

At 3 years the loosening rate was 23% reaching 64% at 6 years after the index procedure. It was present in all age groups, with a peak in the 24 to 49 year age group. Males and females had the same occurrence. When it was present this was always in zone 1. It was present in 6% of patients in zone 7, but then always associated with zone 1 changes. High and standard off-set stems had the same loosening rates. The looser fit of the stem the higher the incidence of loosening. There was no correlation to the type of bearing surface or the degree of calcar resorption. Those patients with a BMI of 25 – 35 had lower loosening rates compared to those with higher or lower BMI's.

We postulate that cancellous bone on-growth onto the hydroxyapatite coating associated with loading flexural micro-motion leads to hydroxyapatite being pulled off the smooth stem substrate in zone 1. Progressive delamination of the hydroxyapatite then occurs. The triple-tapered design though imparts continued stability.

We report high loosening rates in the Corail stem and suggest a mechanism for its development.

Objectives

The objectives of this study were: 1) to examine osteophyte formation, subchondral bone advance, and bone marrow lesions (BMLs) in osteoarthritis (OA)-prone Hartley guinea pigs; and 2) to assess the disease-modifying activity of an orally administered phosphocitrate ‘analogue’, Carolinas Molecule-01 (CM-01).

Aims

The aims of this study were to evaluate the clinical and radiological outcomes of the Universal-2 total wrist arthroplasty (TWA) in patients with rheumatoid arthritis.

Aims

Our aim was to perform a systematic review of the literature to assess the incidence of post-operative epidural haematomas and wound infections after one-, or two-level, non-complex, lumbar surgery for degenerative disease in patients with, or without post-operative wound drainage.

Perthes disease is a childhood disorder often resulting in femoral head deformity. Categorical/dichotomous outcomes of deformity are typical clinically, however quantitative, continuous measures, such as Sphericity Deviation Score (SDS), are critical for studying interventions. SDS uses radiographs in two planes to quantify femoral head deformity. Limitations of SDS may include non-orthogonal planes and lost details due to projections. We applied this method in 3D, with specific objectives to: 1. Develop SDS-like sphericity measures from 3D data 2. Obtain 2D and 3D sphericity for normal and Perthes hips 3. Compare slice-based (3D) and projection-based (2D) sphericity CT images of 16 normal (8 subjects) and 5 Perthes hips (4 subjects) were segmented to create 3D hip models. Ethics board approval was obtained for this study. SDS consists of roundness error (RE) in two planes and ellipsoid deformation (ED) between planes. We implemented a modified SDS which was applied to (a) orthogonal projections simulating radiographs (sagittal/coronal; 2D-mSDS), and (b) largest radii slices (sagittal/coronal; 3D-mSDS). Mean 2D-mSDS was higher for Perthes (27.2 (SD 11.4)) than normal (11.9 (SD 4.1)). Mean 3D-mSDS showed similar trends, but was higher than 2D (Perthes 33.6 (SD 5.3), normals 17.0 (SD 3.1)). Unlike 2D-mSDS, 3D-mSDS showed no overlap between groups. For Perthes hips, 2D-mSDS was consistent with SDS. For normal hips, 2D-mSDS was higher than expected (similar to Stulberg II). Projection-based (2D) measures may produce lower mSDS due to spatial averaging. Slice-based (3D) measures may better distinguish between normal and Perthes shapes, which may better differentiate effectiveness of treatments.

The accurate assessment of skeletal maturity is essential in the management of orthopaedic conditions in the growing child. In order to identify the time of peak height velocity (PHV) in adolescents, two systems for assessing skeletal maturity have been described recently; the calcaneal apophyseal ossification method and the Sanders hand scores.

The purpose of this study was to compare these methods in assessing skeletal maturity relative to PHV. We studied the radiographs of a historical group of 94 healthy children (49 females and 45 males), who had been followed longitudinally between the ages of three and 18 years with serial radiographs and physical examination. Radiographs of the foot and hand were undertaken in these children at least annually between the ages of ten and 15 years. We reviewed 738 radiographs of the foot and 694 radiographs of the hand. PHV was calculated from measurements of height taken at the time of the radiographs.

Prior to PHV we observed four of six stages of calcaneal apophyseal ossification and two of eight Sanders stages. Calcaneal stage 3 and Sanders stage 2 was seen to occur about 0.9 years before PHV, while calcaneal stage 4 and Sanders stage 3 occurred approximately 0.5 years after PHV.

The stages of the calcaneal and Sanders systems can be used in combination, offering better assessment of skeletal maturity with respect to PHV than either system alone.

Cite this article: Bone Joint J 2015;97-B:1710–17.

The aim of our study was to describe the characteristics, treatment, and outcomes of patients with periprosthetic joint infection (PJI) and normal inflammatory markers after total knee arthroplasty (TKA) and total hip arthroplasty (THA).

In total 538 TKAs and 414 THAs underwent surgical treatment for PJI and met the inclusion criteria. Pre-operative erythrocyte sedimentation rate (ESR) and C-reactive protein level (CRP) were reviewed to identify the seronegative cohort. An age- and gender-matched cohort was identified from the remaining patients for comparison. Overall, 4% of confirmed infections were seronegative (21 TKA and 17 THA). Of those who underwent pre-operative aspiration, cultures were positive in 76% of TKAs (n = 13) and 64% of THAs (n = 7). Cell count and differential were suggestive of infection in 85% of TKA (n = 11) and all THA aspirates (n = 5). The most common organism was coagulase-negative Staphylococcus. Seronegative infections were associated with a lower aspirate cell count and a lower incidence of Staphylococcus aureus infection. Two-stage revision was performed in 35 cases (95%). At a mean of five years (14 to 162 months) following revision, re-operation for infection occurred in two TKAs, and one THA. From our study we estimate around 4% of patients with PJI may present with normal ESR and CRP. When performed, pre-operative aspirate is useful in delivering a definitive diagnosis. When treated, similar outcomes can be obtained compared with patients with positive serology.

Cite this article: Bone Joint J 2015;97-B:939–44.

A retrospective review was performed of patients undergoing primary cementless total knee replacement (TKR) using porous tantalum performed by a group of surgical trainees. Clinical and radiological follow-up involved 79 females and 26 males encompassing 115 knees. The mean age was 66.9 years (36 to 85). Mean follow-up was 7 years (2 to 11). Tibial and patellar components were porous tantalum monoblock implants, and femoral components were posterior stabilised (PS) in design with cobalt–chromium fibre mesh. Radiological assessments were made for implant positioning, alignment, radiolucencies, lysis, and loosening. There was 95.7% survival of implants. There was no radiological evidence of loosening and no osteolysis found. No revisions were performed for aseptic loosening. Average tibial component alignment was 1.4° of varus (4°of valgus to 9° varus), and 6.2° (3° anterior to 15° posterior) of posterior slope. Mean femoral component alignment was 6.6° (1° to 11°) of valgus. Mean tibiofemoral alignment was 5.6° of valgus (7° varus to 16° valgus). Patellar tilt was a mean of 2.4° lateral (5° medial to 28° lateral). Patient satisfaction with improvement in pain was 91%. Cementless TKR incorporating porous tantalum yielded good clinical and radiological outcomes at a mean of follow-up of seven-years.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):87–92.

Although it is clear that opening-wedge high tibial osteotomy (HTO) changes alignment in the coronal plane, which is its objective, it is not clear how this procedure affects knee kinematics throughout the range of joint movement and in other planes.

Our research question was: how does opening-wedge HTO change three-dimensional tibiofemoral and patellofemoral kinematics in loaded flexion in patients with varus deformity?Three-dimensional kinematics were assessed over 0° to 60° of loaded flexion using an MRI method before and after opening-wedge HTO in a cohort of 13 men (14 knees). Results obtained from an iterative statistical model found that at six and 12 months after operation, opening-wedge HTO caused increased anterior translation of the tibia (mean 2.6 mm, p <  0.001), decreased proximal translation of the patella (mean –2.2 mm, p <  0.001), decreased patellar spin (mean –1.4°, p < 0.05), increased patellar tilt (mean 2.2°, p < 0.05) and changed three other parameters. The mean Western Ontario and McMaster Universities Arthritis Index improved significantly (p < 0.001) from 49.6 (standard deviation (sd) 16.4) pre-operatively to a mean of 28.2 (sd 16.6) at six months and a mean of 22.5 (sd 14.4) at 12 months.

The three-dimensional kinematic changes found may be important in explaining inconsistency in clinical outcomes, and suggest that measures in addition to coronal plane alignment should be considered.

Cite this article: Bone Joint J 2014; 96-B:1214–21.

Malpositioning of the trochanteric entry point during the introduction of an intramedullary nail may cause iatrogenic fracture or malreduction. Although the optimal point of insertion in the coronal plane has been well described, positioning in the sagittal plane is poorly defined.

The paired femora from 374 cadavers were placed both in the anatomical position and in internal rotation to neutralise femoral anteversion. A marker was placed at the apparent apex of the greater trochanter, and the lateral and anterior offsets from the axis of the femoral shaft were measured on anteroposterior and lateral photographs. Greater trochanteric morphology and trochanteric overhang were graded.

The mean anterior offset of the apex of the trochanter relative to the axis of the femoral shaft was 5.1 mm (sd 4.0) and 4.6 mm (sd 4.2) for the anatomical and neutralised positions, respectively. The mean lateral offset of the apex was 7.1 mm (sd 4.6) and 6.4 mm (sd 4.6), respectively.

Placement of the entry position at the apex of the greater trochanter in the anteroposterior view does not reliably centre an intramedullary nail in the sagittal plane. Based on our findings, the site of insertion should be about 5 mm posterior to the apex of the trochanter to allow for its anterior offset.

Cite this article: Bone Joint J 2014;96-B:1274–81.

Treatment of an infected total elbow replacement (TER) is often successful in eradicating or suppressing the infection. However, the extensor mechanism may be compromised by both the infection and the surgery. The goal of this study was to assess triceps function in patients treated for deep infection complicating a TER. Between 1976 and 2007 a total of 217 TERs in 207 patients were treated for infection of a TER at our institution. Superficial infections and those that underwent resection arthroplasty were excluded, leaving 93 TERs. Triceps function was assessed by examination and a questionnaire. Outcome was measured using the Mayo Elbow Performance Score (MEPS).

Triceps weakness was identified in 51 TERs (49 patients, 55%). At a mean follow-up of five years (0.8 to 34), the extensor mechanism was intact in 13 patients, with the remaining 38 having bone or soft-tissue loss. The mean MEPS was 70 points (5 to 100), with a mean functional score of 18 (0 to 25) of a possible 25 points.

Infection following TER can often be eradicated; however, triceps weakness occurs in more than half of the patients and may represent a major functional problem.

Cite this article: Bone Joint J 2014;96-B:82–7.

Objectives

We aimed to determine the effect of surgical approach on the histology of the femoral head following resurfacing of the hip.

This paper presents a methodology for measuring the femoro-pelvic joint angle based on in vivo magnetic resonance imaging (MRI) images taken under weight-bearing conditions. We assess the reproducibility of angle measurements acquired when the subject is asked to repeatedly assume a reference position and perform a voluntary movement.

We scanned a healthy subject in a lying position in a 3T MRI scanner to obtain high resolution (HR) images including two transverse T1-weighted TSE sequence scans at the pelvis and knee and a sagittal T1-weighted dual sense scan at the hip joint. We then scanned the same subject in a weight-bearing configuration in a 0.5T open MRI scanner to obtain related low resolution (LR) images of the femur and acetabulum. Four scan cycles were obtained with the subject being removed and reinserted between cycles in the Open MRI scanner. In each cycle, a block was inserted (up position) and removed (down position) under the subject's foot.

The femur and acetabulum bone models were manually segmented and the models from the LR (sitting) images were registered to the HR (supine) images. The femoroacetabular angles relative to the LR scanning plane for four cycles were calculated. The femoral angle relative to the scanner were quite repeatable (SD < 0.9°), the pelvic angles less so (SD ∼2.6–4.3°). The hip flexion angle ranged from 23°–34° in the down and up positions, respectively, so the block induced a mean angle change in the flexion direction of approximately 11° (SD = 1.7°).

We found that the femoral position could be accurately re-acquired upon repositioning, while the pelvic position was notably more variable. Limb position changes induced by inserting a block under the subject's foot were consistent (standard deviations in the relative attitude angles under 2°). Overall, our measurement method produces plausible measures of both the femoroacetabular angles and the changes induced by the block, and the reproducibility of relative joint changes is good.

ACKNOWLEDGMENTS: Dr. Kang was supported by the National Science and Engineering Research Council of Canada (NSERC) through a Postdoctoral Fellowship and conducted her research at the Centre for Hip Health and Mobility at Vancouver General Hospital, Canada.

Purpose

The undulating pattern of the distal femur is well recognized. Radiographs do not always represent the full extent of the undulations. With recent increasing use of guided growth technique in the distal femur, it is important to define safe zones for screw placement.

Purpose

Measurements of patellar kinematics are essential to investigate the link between anterior knee pain following knee arthroplasty and patellar maltracking. A major challenge in studying the patellofemoral (PF) joint postoperatively is that the patellar component is only partially visible in the sagittal and close-to-sagittal radiographs. The narrow angular distance between these radiographs makes the application of conventional bi-planar fluoroscopy impossible. In this study a methodology has been introduced and validated for accurate estimation of the 3D kinematics of the PF joint post-arthroplasty using a novel multi-planar fluoroscopy approach.

Purpose

Primary internal fixation of uncomplicated scaphoid fractures offers many advantages compared to conventional casting. However, ideal fixation placement along the central scaphoid axis can be challenging, especially if the procedure is performed percutaneously. Because of the lack of direct visualization, percutaneous procedures demand liberal use of imaging, thereby increasing exposure to harmful radiation.

It has been demonstrated that computer-assisted navigation can improve the accuracy of guidewire placement and reduce X-ray exposure in procedures such as hip fracture fixation. Adapting the conventional computer-assist paradigm, with preoperative imaging and intraoperative registration, to scaphoid fixation is not straightforward, and thus a novel tactic must be conceived.

Purpose

Introduce an Integrated Approach for Orthopedic-Sports Medicine Practice and Patient Care Management that

Is built around effective and efficient surgical techniques, and patient care management processes

Integrates Operations and Service Excellence best practices with patient care management processes

Integrates orthopedic care delivery between outpatient clinic, pre-surgery, surgery, inpatient, (acute care) and post acute care settings

Delivers exceptional clinical, patient satisfaction and financial outcomes as validated by independent national healthcare benchmarking organization

Helps position Ortho-Sports medicine services for strategic growth

Is replicable to develop Ortho-Sports Medicine Centers of Excellence

Presentation illustrates the ‘Ten Elements’ approach to implement the Ortho-Sports Medicine Centers of Excellence and demonstrate the effectiveness of the approach with an outcomes study from over 1000 total knee arthroplasty (TKA) procedures. During the presentation, the speakers would share the key clinical, patient satisfaction, and financial outcomes achieved by the implementation of the best practices defined in our ‘Ten Elements’ approach. All performance data elements are collected, validated and analyzed by an independent third party, national healthcare benchmarking company.

During the presentation Dr. Bramlett would elaborate on the surgical protocol, and the key differentiating steps in procedure technique from traditional approach that significantly enhances procedure effectiveness, efficiency and lowers the patient complication rate as demonstrated by benchmarking data. Speakers would further present the key elements of Total Knee Arthoplasty procedure that focus on patient education, patient participation in pre-surgical weight loss and pre-habilitation program, anesthesia approach, avoiding tourniquet use and deep veen thrombosis (DVT) risk reduction, early post operative patient ambulation and weight bearing, and post operative patient management approach. On average the ortho-sports medicine clinical of Alabama TKA patients are disharged from the hospital in 2.6 days, and experience 65 percent less complications than expected for a similar patient population and assume early control of their independent functionality.

Objectives

To study the vascularity and bone metabolism of the femoral head/neck following hip resurfacing arthroplasty, and to use these results to compare the posterior and the trochanteric-flip approaches.

Purpose: Patellar bracing is a common, mechanical-based treatment strategy for patellofemoral osteoarthritis (OA). It is thought that the brace corrects patellar tracking, however, this correction has not been quantified in the OA population. Through advances in magnetic resonance imaging (MRI), we can now assess patellar tracking in three-dimensions.

Method: We assessed three-dimensional patellar tracking in ten subjects with symptomatic radiographic patellofemoral knee OA using a validated, quasi-static, MRI-based method. Four conditions were studied:

no knee brace, no load,

Patellar tracking (flexion, spin and tilt; proximal, lateral and anterior translation) was assessed. Comparisons were made at 1° increments over the coincidental range of knee flexion between the no-brace and brace conditions, at no load and 15% BW load, using a paired t-test with Bonferroni correction.

Results: All subjects (7 female, 3 male, 60.9±1.3 yrs, 89.5±19.3 kg) had radiographic lateral patellofemoral OA and seven had concomitant tibiofemoral OA (KL grade≥2). Under no load, the brace extended (mean=2.7°, CI=[2.4°, 2.9°], P< 0.001) and medially tilted (mean=−1.4°, CI=[−1.6°, −1.2°], P< 0.001) the patellae and shifted them distally (mean=0.8mm, CI=[0.6mm, 0.9mm], P< 0.001), medially (mean=0.5mm, CI=[0.5mm, 0.6mm], P< 0.001) and posteriorly (mean=0.6mm, CI=[0.5mm, 0.6mm], P< 0.001). Under 15% BW load, the brace extended the patella (mean=2.4°, CI=[2.1°, 2.8°], P< 0.001) and shifted them distally (mean=1.3mm, CI=[1.1mm, 1.4mm], P< 0.001), medially (mean=0.8mm, CI=[0.7mm, 0.9mm], P< 0.001) and posteriorly (mean 0.6mm, CI=[0.5mm, 0.7mm], P< 0.001).

Conclusion: The brace extended the patellae for both loading conditions, suggesting that patellar flexion/extension is restricted by the brace. The brace tilted the patellae medially under no load only, suggesting when the quadriceps are active (15% BW load) the brace has little effect for tilt. While the effect of bracing on patellar tracking may appear small, the differences are of similar magnitude to those observed between normals and patients with patellofemoral pain, suggesting that braces may produce clinically significant changes in patellar tracking.

Purpose: Subchondral cortical and trabecular bone mineral density (BMD) may increase and/or decrease during different stages of osteoarthritis (OA) disease progression. 2D in-vivo imaging studies examining direct associations between increased proximal tibial BMD and knee OA offer conflicting results, which may be due to the inherent limitations of 2D BMD imaging tools. Our objective was to compare existing and novel 3D imaging techniques for distinguishing subchondral bone properties in OA and normal cadaveric tibiae.

Method: Eight intact cadaver knees from five donors (4M:1F; age: 77+/−10) were repositioned and scanned three times using QCT (0.5mm isotropic resolution, 0.15mSv dosage). BMD was assessed using

computed tomography absorptiometry (CT-OAM) which uses maximum intensity projections to assesses peak density values within subchondral bone, and

Average BMD at normalized depths of 0–2.5mm, 2.5–5.0mm, and 5.0–10mm from the surface were assessed using CT-TomasD. Regional analyses were performed consisting of:

medial/lateral (M/L) BMD ratio, and

Each bone was assessed for OA using a modified-KL scoring system: Normal (mKL=0); Early-OA (1–2); and Late-OA (3–4).

Results: OA was identified in four compartments of three tibiae (1 late OA+valgus, 1 late OA+varus, 1 early OA+neutral). Larger density differences between OA and normal knees were noted using CT-TOMASD compared with CT-OAM. CT-TomasD demonstrated that the two knees with late OA demonstrated M/L BMD ratios differing by more than 3.4 SD compared with normals, with peak cores higher than normals across all depths. The knee with early OA and neutral alignment demonstrated M/L ratios less than normals while core differences were highest proximally, with density becoming lower than normals with increasing depth.

Conclusion: CT-TomasD demonstrated larger differences between OA and normal subjects when compared with CT-OAM differences. This may be due to CT-OAM primarily assessing peak density within the thin subchondral cortical endplate; a region demonstrating fairly uniform peak densities within a limited range.

Purpose: Radiostereometric Analysis (RSA) is used to measure migration and inducible displacement (ID) of orthopedic implant devices to allow early prediction of implant failure (eg. Aseptic loosening). Total Ankle Arthroplasty (TAA) is used for the treatment of end-stage ankle arthritis. First generation TAA implant have meet with widespread failures while some second generation TAA implants are showing improved results. In this study RSA is used to evaluate the biomechanical properties of a new third generation TAA implant in an attempt to set a standard for the biomechanical evaluation on TAA implants in-vivo.

Method: Patients undergoing TAA were enrolled consecutively (n=12; 7 males; mean age=59 years; mean BMI=29) and had 8 markers (0.08mm) inserted in both the tibia and talus during surgery. Standing, weight-bearing RSA exams were performed at 3 and 6 months and compared to concurrent supine exams to determine component ID.

Results: For tibial components: at six months the components had translated posteriorly (0.3mm±0.5) and proximally (0.5mm±0.2), tilted into varus (0.5°±1.3), and tilted posteriorly (0.4°±0.8). The magnitudes of ID for the tibial components were moderate (mean < 0.2mm and 0.5°, standard deviation < 0.3mm and 2.2° in each direction). For talar components: at six months the components had translated distally (0.28mm±0.35), rotated internally (0.21°±1.32) and tilted posteriorly (0.15°±0.90). There was varus/valgus tilt measured in the talar components but there was no consistent direction of migration (0.03°±1.4). At six months the magnitudes of ID for the talar components were small (mean < 0.1mm and 0.25°, standard deviation < 0.2mm and 0.6° in each direction).

Conclusion: An RSA methodology has been established to predict stability.

Our aim was to determine the effect of the initial pattern of fracture and the displacement of fragments on the outcome of proximal humeral fractures treated conservatively. We followed 93 consecutive patients prospectively for one year. Final movement and strength were compared with those of the contralateral side. The final American Shoulder and Elbow Society score and the Disabilities of Arm, Shoulder and Hand and Short-Form 36 questionnaires were compared with those provided by the patient on the day of the injury. Radiographs and CT scans with three-dimensional reconstruction were obtained in all patients. The pattern of the fracture and the displacement of individual fragments were analysed and correlated with the final outcome. There were two cases of nonunion and six of avascular necrosis. The majority of the fractures (84 patients; 90%) followed one of the following four patterns: posteromedial (varus) impaction in 50 patients (54%), lateral (valgus) impaction in 13 (14%), isolated greater tuberosity in 15 (16%), and anteromedial impaction fracture in six (6%). Head orientation, impaction of the surgical neck and displacement of the tuberosity correlated strongly with the outcome.

In fractures with posteromedial impaction, a poor outcome was noted as the articular surface displaced inferiorly increasing its distance from the acromion. A poorer outcome was noted as a fractured greater tuberosity displaced medially overlapping with the posterior articular surface. Lateral impaction fractures had a worse outcome than other patterns of fracture.

Recently, gender-specific designs of total knee replacement have been developed to accommodate anatomical differences between males and females. We examined a group of male and female distal femora matched for age and height, to determine if there was a difference in the aspect ratio (mediolateral distance versus anteroposterior distance) and the height of the anterior flange between the genders. The Hamann-Todd Collection provided 1207 skeletally mature cadaver femora. The femoral length, the anteroposterior height, height of the lateral and medial flanges and the mediolateral width were measured in all the specimens. The mechanical axis of the femur, the cut articular width and the aspect ratio were assessed. Statistical analysis of the effect of gender upon the aspect ratio and the lateral and medial flanges was undertaken, controlling for age, height and race.

The mean aspect ratio of male femora was 1.21 (sd 0.07) and of female femora it was 1.16 (sd 0.06) (p < 0.001). There was no significant difference between male and female specimens in the mean size of the lateral flange (6.57 mm (sd 2.57) and 7.02 mm (sd 2.36), respectively; p = 0.099) or of the medial flange (3.03 mm (sd 2.47) and 3.56 mm (sd 2.32), respectively; p = 0.67). Future work in the design of knee prostheses should take into account the overall variability of the anatomy of the distal femur.

Background: Diagnosis and treatment of cancer are highly stressful for patients. Everyday life is disrupted for the vast majority of patients and their relatives and the cancer experience often results in physical, psychological, social, practical, and spiritual concerns.25% to 40% of cancer survivors continue to suffer from distress.

Goal: To improve the referral to specific professionals.

Intervention: Implementation of the distress thermometer: for the future demand on healthcare, a National Cancer Control Program was developed. Two objectives are the availability and introduction of a validated screening instrument capable of indicating the need for specialized psychosocial assistance and the inclusion of screening for psychosocial problems in the national guidelines for oncologic care. These 2 objectives are in line with the American National Comprehensive Cancer Network (NCCN) practice guideline of distress management. This program introduced the Distress Thermometer (DT), an easily understood, self-reported measure of distress. Patients are asked to rate their overall distress on a visual analogue scale (a thermometer) from 0 (no distress) to 10 (extreme distress).

Implementation: Baseline measurements were done in 2008. In January 2009 we started using the distress thermometer at the orthopedic oncology outpatient clinic. The first results of the baseline measurements and the implementation so far will be presented during the EMSOS 2009.

A longer stay in the hospital after primary total hip replacement is consistent with an increased morbidity and slower recovery for patients. In addition, it is among the more costly aspects of a total joint replacement. A process, which reduces the length of stay following this procedure and synchronically maintains the high standards of safe care would certainly improve the clinical practice and provide financial benefits.

Our objective was to evaluate the efficiency of a holistic perioperative, accelerated recovery programme following this procedure and in particular to assess its impact in the shot term patient’s recovery, morbidity, complications, readmission rate and cost savings for the NHS.

Eighty-nine patients participated in our rapid recovery programme, which is a comprehensive approach to patient care, combining individual pre-operative patient education, pain management, infection control, continuous nursing and medical staff motivation as well as intensive physiotherapy in the ward and the community. Forty-eight male and 41 female patients with an average age of 69 (range-50 to 87) underwent a total hip replacement in an NHS District General Hospital. The average BMI was 28 (range-18 to 39) and the average ASA 2.3 (range-1 to 4). The procedure was performed by 3 different surgeons using the same operative standards. A standardised post-operative protocol was followed and the patients were discharged when they were medically fit and had achieved the ward physiotherapy requirements. They were then daily followed up by a community orthopaedic rehabilitation team in patient’s own environment as long as it was required.

The average length of stay was reduced from 7.8 days to 5. There was no increase in complications–or readmissions rate while there were significant cost savings. The waiting list for this surgery was reduced and the patient’s satisfaction was high.

The rapid recovery programme for primary total hip replacement surgeries has been proved to be an efficient method of reducing the length of stay in hospital and consequently the financial costs while it ensures the safe and effective peri-operative management of patients.

Introduction: Geometry of the proximal femur has been identified as a risk factors for hip fracture. It is also suggested that the geometry of the proximal femur can influence the fracture type.

Aims: To identify if proximal geometry and hip fractures are related in two different population groups. Scotland–Monklands General Hospital, Lanarkshire–and Australia -Flinders Medical Centre, Adelaide.

Methods: Retrospective comparison of length and width of the femoral necks in 200 hip fracture patients. 100 patients in the Australian group and 100 patients in the Scottish group were analysed. 50 intracapsular and 50 intertrochanteric fractures were included in each group. All measurements where made from standardised digital anteroposterior radiographs. We attempted to correlate the length and width of the femoral neck with the fracture type.

Results: The populations were matched for age and sex, with the majority of fractures sustained by women. The results for the both populations show that a patient sustaining an intracapsular fracture is more likely to have a longer femoral neck (mean 40.56mm; Scottish population, 39mm; Australian population) than one sustaining an intertrochanteric fracture (mean 31.70mm; Scottish population, 29mm; Australian population) [P < 0.0001]. The femoral neck was also narrower in the intracapsular group. This was significant in Scottish population (mean 38.56mm, P < 0.03), but not in the Australian population (mean 38.3mm, P = 0.067). We also found that men had longer, wider femoral necks (P < 0.0001) compared to the female group.

Discussion: We found that hip fracture pattern is linked to proximal femoral geometry. This relationship is statistically significant in both population groups. Anthropologically, as the human race evolves and people get taller, their femoral neck lengths are increasing. This could translate into a change in the number and type of hip fractures. Intracapsular fractures may predominate and this could have implications on both treatment outcomes and resources for hip fracture patients.

Purpose: To evaluate the functional outcome of operatively treated Lisfranc injuries.

Method: Over a 7-year interval from 1998 to 2005, 184 skeletally mature patients were identified retrospectively with operatively treated Lisfranc injuries. 85 patients had prospectively measured SMFA functional outcomes and satisfaction surveys. The gender was 37 males and 48 females. Mean age was 39 years (range 17–93).

Results: The mechanism was fall (31), MVA (24), crush (15), equestrian (5), or twisting (10). Patients were operatively treated with open reduction internal fixation (ORIF, 53) or primary arthrodesis (PA, 32). The SMFA reliability for this patient sample was 0.892. The function and bother outcomes were 19.4 and 15.8, respectively. The function (21.5 vs. 16.0, p=.11) and bother (17.5 vs. 13.0, p=.25) outcomes were not significantly different for ORIF vs. PA, respectively. In the ORIF group, HW removal (40 of 53) performed better than HW retention (13 of 53) with outcome bother but not function measures of (14.7 vs. 26.1, p< 0.05).

Conclusion: If performed well, either ORIF or PA technique function well. Patients are more satisfied with the results and appearance of PA over ORIF. HW removal compared to HW retention positively affect bother not function measures. Secondary surgeries negatively affect both bother and function measures. Patients with pain, associated foot or polytrauma injuries function worse.

Whole blood metal ion levels remain a concern in those patients undergoing total hip replacement with metal bearing surfaces. The determination of baseline reference levels are essential if useful information can be gleaned from in vivo studies of functioning implants. We set out to prospectively determine chromium and cobalt metal ion concentrations in patients undergoing total hip replacement to determine reference levels of these metal ions.

100 patients with normal renal function, no occupational or environmental exposure to cobalt and chromium, and an absence of implanted metals were recruited into the study. Metal ion levels were determined using two different assay methods. Both ICP-MS (Inductively Coupled Plasma Mass Spectroscopy) and GFAAS (Graphite Furnace Atomic Adsorption Spectroscopy) are well recognized analytical techniques for the quantification of trace elements. Levels were correlated with gender, age and place of residence.

There was considerable variability in whole blood metal ion levels, with the ICPMS being more sensitive and consistent than the GFAAS method. Direct comparison of concentration levels determined by the two methods revealed no significant correlation. There was no correlation with age, gender and place of residence

Our findings would favour the use of the ICP-MS to determine reference levels and as a baseline for metal ion surveillance pre-operatively in patients undergoing metal-on-metal total hip replacements. We also determined that changes in whole blood metal ion levels are more significant than actual levels in patients who have undergone total hip replacement.

Purpose: Osteoarthritis (OA) is the most common form of arthritis in the United States and according to the National Institutes of Health, affects over 21 million people. This degenerative joint disease has repeatedly been linked to obesity. It is hypothesized that obesity, defined as a body mass index (BMI) over 30 kg/m2, increases the incidence of OA through increased joint pressure and disruption of normal metabolism. The actual changes in metabolism resulting from obesity and possibly preceding OA have not been thoroughly investigated. The purpose of this study was to identify the relationship between chondrocyte metabolism and BMI in osteoarthritic tissue.

Method: Grade 0 or 1 cartilage was removed from the medial and/or lateral femoral condyles after total knee arthroplasty. Isolated chondrocytes were then resus-pended in alginate beads at 2×106 cells/mL. The beads were equilibrated in media containing 10% fetal bovine serum for 7 days (37°C) and then separated into wells (8 beads/well) with 1 mL media. Media was replaced every 48 hours. At day 5, 9, and 13 days, glycosamino-glycan (GAG) content was measured in the cell pellet, alginate, and saved media using the dimethylmethylene blue (DMMB) assay. The DMMB results were normalized to DNA content. All procedures were approved by the University of Wisconsin – Madison, Institutional Review Board.

Results: At day 5, the average normalized GAGs from the obese group (BMI > 30 kg/m2) was > 4-fold higher than the average normalized GAGs in the non-obese group (BMI < 30 kg/m2). The 4-fold difference in normalized GAGs continued at day 9 with significance (p=0.0087) and widened at day 13, without significance. Some osteoarthritic knees had less tissue quality, therefore GAG testing was limited to earlier study days resulting in variable sample numbers for each study day.

Conclusion: The study results reveal a significant relationship between normalized GAGs and BMI in this population of osteoarthritic patients, supporting the connection between osteoarthritis and obesity previously reported. Higher patient BMI (> 30 kg/m2) may be similar to dynamic compression injuries that cause increased GAG synthesis in response to cartilage damage. In conclusion, elevated normalized GAGs in obese patients’ chondrocytes suggests increased cartilage damage.

Purpose: Femoral neck fracture collapse and shortening has been a desired effect of parallel screw fixation to promote healing. While some degree of compression might be beneficial, it remains unknown whether the effects of uncontrolled femoral neck shortening leads to detectable functional impairment. We aimed to evaluate the effect of shortening and varus collapse after cancellous screw fixation of femoral neck fractures on patient functional status and quality of life.

Method: The databases of four University Hospitals were screened to identify patients with a healed isolated femoral neck fracture. Patients were contacted by telephone to complete Short-form 36(SF36) and Euroquol-5D(EQ5D) questionnaires (Primary outcome: SF36 physical functioning score[PF]). Femoral neck shortening and varus collapse were assessed by three independent reviewers blinded to functional outcome results based on the latest follow-up radiographs and categorized into three grades: None/Mild (within 5mm/5°), Moderate (5–10mm/5–10°), and Severe (> 10mm/> 10°). The minimal clinically important difference for SF36 PF score equals 12 points (1/2 of Standard deviation).

Results: Out of 660 patients screened at all four sites 70 met the inclusion criteria and were available for follow-up. The average follow-up was 20 months and an the average age was 71 years. Overall, there were 24/70 patients with none/mild femoral neck shortening, 25/70 with moderate shortening and 21/70 with severe shortening. Patients with severe shortening of their hip had significantly lower SF36 physical functioning scores (No/Mild vs. Severe shortening: 74 vs. 42 points, p=0.01). Similar important effects occurred with moderate shortening suggesting a gradient effect (No/Mild vs. Moderate shortening: 74 vs. 53 points). Some degree of varus collapse occurred in 39% of the patients and correlated moderately with the occurrence of shortening (r=0.66, p< 0.001).

Conclusion: A large proportion of displaced and undisplaced femoral neck fractures fixed with cancellous screws heal in a shortened position (66%) and varus (39%). The differences in function we observed represent patient important declines and suggest that uncontrolled sliding with cancellous screw fixation has limitations.

In an osteological collection of 3100 specimens, 70 were found with unilateral clavicular fractures which were matched with 70 randomly selected normal specimens. This formed the basis of a study of the incidence of arthritis of the acromioclavicular joint and the effect of clavicular fracture on the development of arthritis in the ipsilateral acromioclavicular joint. This was graded visually on a severity scale of 0 to 3. The incidence of moderate to severe arthritis of the acromioclavicular joint in normal specimens was 77% (100 specimens). In those with a clavicular fracture, 66 of 70 (94%) had arthritis of the acromioclavicular joint, compared to 63 of 70 (90%) on the non-injured contralateral side (p = 0.35).

Clavicles with shortening of 15 mm or less had no difference in the incidence of arthritis compared to those with shortening greater than 15 mm (p = 0.25). The location of the fracture had no effect on the development of arthritis.

INTRODUCTION. The grip test is usually included in common protocols of functional evaluation. Till today a dynamometer Jamar was used to evaluate Maximum Isometric Strength. At this moment we use isokinetic dynamometers to analyse grip strength in isokinetic way. As a few bibliographic references for this valuation techniques we have designed an study at healthy population to obtain the normal values of grip strength and the influence of individual factors, like sex, age and side-dominance.

MATERIAL AND METHODS. A 321 healthy hands serial was included. The average age was 37.2 years old (ranged 17–63). Mostly of them were men (211 cases, 65.7%). 150 are side-dominant cases (46.7%). All of them has been valuated by Dexter Hand Evaluation. Two speeds 30°/s and 60°/s was used in the study. And the extent used was 4.3 cm. Five trials was done in each velocity. We acquired Maximum Isokinetic Strength and Work.

RESULTS. The values were for strength (Kg) 38.4 at 30°/s and 35.0 at 60°/s and for work (Kg-cm) 98.5 at 30°/s and 86.7 at 60°/s. The side-dominant hand are stronger than non-dominant ones (10.3% in 30°/s, p< 0.001; 11.9% in 60°/s, p< 0.001). Women had less strength than men (37% in both speeds, p< 0.001). The age has less important as isokinetic strength values are more or less the same till 39 years old. After that there is a slow drop of the strength in aged cases.

At last we show tables of normal values at healthy population. The influence of sex and side-dominant are shown as a percentile distribution.

CONCLUSIONS. The isokinetic strength evaluation of hand grip is a very value method in the functional evaluation of the hand. This study gives normal values in healthy hands and the influence of sex, age and side-dominance.

We have developed a novel method of calculating the radiological magnification of the hip using two separate radio-opaque markers. We recruited 74 patients undergoing radiological assessment following total hip replacement. Both the new double marker and a conventional single marker were used by the radiographer at the time of x-ray. The predicted magnification according to each marker was calculated, as was the true radiological magnification of the components. The correlation between true and predicted magnification was good using the double marker (r = 0.90, n = 74, p < 0.001), but only moderate for the single marker (r = 0.50, n = 63, p < 0.001). The median error was significantly less for the double marker than for the single (1.1% vs 4.8%, p < 0.001). The double marker method demonstrated excellent validity (intraclass correlation coefficient = 0.89), in contrast to the single marker (0.32).

The double marker method appears to be superior to the single marker method when used in the clinical environment.

We undertook a prospective study in 51 male patients aged between 17 and 27 years to ascertain whether immobilisation after primary traumatic anterior dislocation of the shoulder in external rotation was more effective than immobilisation in internal rotation in preventing recurrent dislocation in a physically active population.

Of the 51 patients, 24 were randomised to be treated by a traditional brace in internal rotation and 27 were immobilised in external rotation of 15° to 20°. After immobilisation, the patients undertook a standard regime of physiotherapy and were then assessed clinically for evidence of instability. When reviewed at a mean of 33.4 months (24 to 48) ten from the external rotation group (37%) and ten from the internal rotation group (41.7%) had sustained a futher dislocation. There was no statistically significant difference (p = 0.74) between the groups.

Our findings show that external rotation bracing may not be as effective as previously reported in preventing recurrent anterior dislocation of the shoulder.

The purpose of this study was to evaluate the impact of dalteparin use on transfusion rates and blood loss in patients undergoing primary total joint arthroplasty at our center.

We prospectively studied the transfusion patterns of 1642 patients who underwent primary total hip or knee arthroplasty between January 2004 and December 2005 by five arthroplasty surgeons. The influence of daltaperin use, release of tourniquet in total knee arthroplasty, and the turnover of house staff were analyzed using SPSS V14.0 statistical software.

We identified seven hundred and three total hip and nine hundred and thirty-nine knee arthroplasty patients. The mean haemoglobin drop was statistically significant between 2004 and 2005 (p< 0.001). This was seen in both hip (p=0.014) and knee (p< 0.001) patients. Subgroup analysis of total knee arthroplasty revealed a significant difference in haemoglobin drop between surgeons who released the tourniquet prior to closure compared to release at the end of the case (p=0.005). In addition, there were significant monthly differences that corresponded with the turnover of house staff (p=0.039). Overall, no statistically significant increase in allogeneic transfusion rates was observed between years, months, and individual surgeons.

The use of dalteparin was found to be associated with a significantly increased haemoglobin drop in primary total joint replacement when compared to warfarin. However, the use of dalteparin was not associated with an increase in allogeneic transfusions at our center. The results also suggest that there may be an advantage to releasing the tourniquet and achieving hemostasis prior to closure in knee arthroplasty. Finally, the results emphasise the importance of educating new house staff on methods to reduce intra-operative blood loss and transfusion rates.

We describe injuries to the posterior root of the medial meniscus in patients with spontaneous osteonecrosis of the medial compartment of the knee. We identified 30 consecutive patients with spontaneous osteonecrosis of the medial femoral condyle. The radiographs and MR imaging were reviewed. We found tears of the posterior root of the medial meniscus in 24 patients (80%). Of these, 15 were complete and nine were partial. Complete tears were associated with > 3 mm of meniscal extrusion. Neither the presence of a root tear nor the volume of the osteonecrotic lesion were associated with age, body mass index (BMI), gender, side affected, or knee alignment. The grade of osteoarthritis was associated with BMI.

Although tears of the posterior root of the medial meniscus were frequently present in patients with spontaneous osteonecrosis of the knee, this does not prove cause and effect. Further study is warranted.

We have studied the effect of shortening of the femoral neck and varus collapse on the functional capacity and quality of life of patients who had undergone fixation of an isolated intracapsular fracture of the hip with cancellous screws. After screening 660 patients at four university medical centres, 70 patients with a mean age of 71 years (20 to 90) met the inclusion criteria. Overall, 66% (46 of 70) of the fractures healed with > 5 mm of shortening and 39% (27 of 70) with > 5° of varus. Patients with severe shortening of the femoral neck had significantly lower short form-36 questionnaire (SF-36) physical functioning scores (no/mild (< 5 mm) vs severe shortening (> 10 mm); 74 vs 42 points, p < 0.001). A similar effect was noted with moderate shortening, suggesting a gradient effect (no/mild (< 5 mm) vs moderate shortening (5 to 10 mm); 74 vs 53 points, p = 0.011). Varus collapse correlated moderately with the occurrence of shortening (r = 0.66, p < 0.001). Shortening also resulted in a significantly lower EuroQol questionnaire (EQ5D) index scores (p = 0.05). In a regression analysis shortening of the femoral neck was the only significant variable predictive of a low SF-36 physical functioning score (p < 0.001).

The aim of this study was to validate the use of three models of fracture fixation in the assessment of technical skills. We recruited 21 subjects (six experts, seven intermediates, and eight novices) to perform three procedures: application of a dynamic compression plate on a cadaver porcine model, insertion of an unreamed tibial intramedullary nail, and application of a forearm external fixator, both on synthetic bone models. The primary outcome measures were the Objective Structural Assessment of technical skills global rating scale on video recordings of the procedures which were scored by two independent expert observers, and the hand movements of the surgeons which were analysed using the Imperial College Surgical Assessment Device.

The video scores were significantly different for the three groups in all three procedures (p < 0.05), with excellent inter-rater reliability (α = 0.88). The novice and intermediate groups specifically were significantly different in their performance with dynamic compression plate and intramedullary nails (p < 0.05). Movement analysis distinguished between the three groups in the dynamic compression plate model, but a ceiling effect was demonstrated in the intramedullary nail and external fixator procedures, where intermediates and experts performed to comparable standards (p > 0.6). A total of 85% (18 of 21) of the subjects found the dynamic compression model and 57% (12 of 21) found all the models acceptable tools of assessment.

This study has validated a low-cost, high-fidelity porcine dynamic compression plate model using video rating scores for skills assessment and movement analysis. It has also demonstrated that Synbone models for the application of and intramedullary nail and an external fixator are less sensitive and should be improved for further assessment of surgical skills in trauma. The availability of valid objective tools of assessment of surgical skills allows further studies into improving methods of training.

We used Laser Doppler flowmetry to measure the effect on the blood flow to the femoral head/neck junction of two surgical approaches during resurfacing arthroplasty. We studied 24 hips undergoing resurfacing arthroplasty for osteoarthritis. Of these, 12 had a posterior approach and 12 a trochanteric flip approach. A Laser probe was placed under radiological control in the superolateral part of the femoral head/neck junction. The Doppler flux was measured at stages of the operation and compared with the initial flux. In both groups the main fall in blood flow occurred during the initial exposure and capsulotomy of the hip joint.

There was a greater reduction in blood flow with the posterior (40%) than with the trochanteric flip approach (11%).

We retrospectively reviewed 21 patients (22 shoulders) who presented with deep infection after surgery to the shoulder, 17 having previously undergone hemiarthroplasty and five open repair of the rotator cuff. Nine shoulders had undergone previous surgical attempts to eradicate their infection. The diagnosis of infection was based on a combination of clinical suspicion (16 shoulders), positive frozen sections (> 5 polymorphonuclear leukocytes per high-power field) at the time of revision (15 shoulders), positive intra-operative cultures (18 shoulders) or the pre-operative radiological appearances. The patients were treated by an extensive debridement, intravenous antibiotics, and conversion to a reverse shoulder prosthesis in either a single- (10 shoulders) or a two-stage (12 shoulders) procedure.

At a mean follow-up of 43 months (25 to 66) there was no evidence of recurrent infection. All outcome measures showed statistically significant improvements. Mean abduction improved from 36.1° (sd 27.8) pre-operatively to 75.7° (sd 36.0) (p < 0.0001), the mean forward flexion from 43.1° (sd 33.5) to 79.5° (sd 43.2) (p = 0.0003), and mean external rotation from 10.2° (sd 18.7) to 25.4° (sd 23.5) (p = 0.0037). There was no statistically significant difference in any outcome between the single-stage and the two-stage group.

Using the Trent regional arthroplasty register, we analysed the survival at ten years of 1198 consecutive Charnley total hip replacements carried out across a single health region of the United Kingdom in 1990. At ten years, information regarding outcome was available for 1001 hips (83.6%). The crude revision rate was 6.2% (62 of 1001) and the cumulative survival rate with revision of the components as an end-point was 93.1%. At five years, a review of this series of patients identified gross radiological failure in 25 total hip replacements which had previously been unrecognised. At ten years the outcome was known for 18 of these 25 patients (72%), of whom 13 had not undergone revision.

This is the first study to assess the survival at ten years for the primary Charnley total hip replacement performed in a broad cross-section of hospitals in the United Kingdom, as opposed to specialist centres. Our results highlight the importance of the arthroplasty register in identifying the long-term outcome of hip prostheses.

We report a case of bifocal rhabdomyosarcoma involving the hand and thigh in an 11-year-old female. We highlight the importance of a thorough clinical examination and an aggressive surgical approach in which each lesion is treated as a separate primary.

Background Elevated plasma levels of D-dimer have been found to be a useful screening tool in the diagnosis of deep venous thrombosis (DVT) in the general population. In the postoperative setting however their role is less clear.

In approximately 73% of NHS trusts D-dimer is a prerequisite test prior to radiological imaging to diagnose DVT.

This study evaluates the effectiveness of D-dimer as a screening tool for DVT in the postoperative period following total hip and knee arthroplasty.

Method Plasma D-dimer levels were measured pre operatively and on post-operative days 1, 3, 5, and 7 in 78 patients undergoing primary total hip or knee arthroplasty. On day 7 patients underwent bilateral duplex ultrasound scanning in order to confirm the absence of DVT.

All patients wore pneumatic foot pumps for DVT prophylaxis. Chemical thromboprophylaxis was not used. All patients were under the care of one surgeon with the same postoperative regimen.

Results D-dimer levels in the post-operative period were characterized by a double peak, on days 1 and 7. Mean day 1 value 3.63 (sd=2.72, range 0.60–14.34), mean day 7 value 2.83 (sd=1.58, range 1.10–10.30). Mean values on days 3 and 5 were 2.52 (sd=2.26, range 0.50–11.85) and 2.45 (sd=1.41, range 0.91–5.05)

Comparing D-dimer levels between hip and knee arthroplasty we found that both groups displayed the same trend in post-operative D-dimer levels (i.e. peaks at days 1 and 7); however levels were significantly higher following knee replacement (At day 7 p< 0.005)

We compared D-dimer levels of these patients with a second group of 43 patients who had a confirmed DVT following hip or knee arthroplasty. The mean D-dimer level in this group was 2.20 (sd=0.98 or range 0.80 – 4.46). This group was subdivided into two groups, those with D-dimer samples before (and including) day 7 and those after. We found a significant difference between the groups (p=0.01). Mean ≤ day 7 = 2.70. Mean > day 7 = 1.97.

The group of patients with Confirmed DVT on or before day 7 were compared with those free of clot. There was no significant difference found between the D-dimer levels of the two groups. (p=0.37)

Conclusion The D-dimer level is never normal (< 0.4mg/l), in the week following total hip or knee replacement and so cannot exclude a DVT. The level it rises to is indistinguishable form that seen in the population with a DVT and so cannot identify those patients in whom further investigation is warranted. Requesting a D-dimer test in this population wastes time and resources and is of no benefit.

Aims: A biomechanical and clinical study was made to compare two nonunion fixation device: the AO dynamic compresiòn plate and a locked intramedullary nail.

Methods: A retrospective review was made of all patients from three major hospitals in the Barcelona area with the diagnosis of aseptic non-union of the humeral shaft. After exclusion criteria series were limited to fifty-four patients, treated between 1992 and 2002. Of these, 35 were women and 19 were men with a median age of 55 (18–91) years. Operative treatment was with plate in 74.1% and locked nail in 25.9%. Statistical analysis was made to compare consolidation rate, consolidation time and complications in both devices and to looking for possible prognostic consolidation factors. We used the Finite element Method to compare the biomechanical behaviour between plate and nail.

Results: The consolidation rate was 78.6% with nail and 70.3% in plate, but this rate has significantly improved (p< 0.05) when plate is used in hypertrophic non-union and nail in atrophic union.

The median consolidation time was 5.73 months with nail and 4.92 months in plate.

The complication rate was 21.4% with nail and 20.0% in plate.

Focus deformation is lesser with nail than plate in anterior bending, axial charge and torsion but no in lateral bending.

Six or more cortical screws beside focus with plate increase consolidation too (p< 0.05).

The consolidation rate in graft group was 70.5% versus 85.7% in group without graft.

Conclusions: Plating provides better results in hypertrophic nonunions and nailing in atrophic nonunions.

Six or more cortical screws beside focus when plate is used improves consolidation rate.

Consolidation not seems be modified by graft use.

As metal-on-metal arthroplasty becomes more widespread, concerns are being raised about the potential dangers of metal particulate debris. We present the case of a benign psoas mass secondary to the presence of such particles. The mass was excised and the hip resurfacing subsequently revised to a total hip replacement.

In developmental dysplasia of the hip, a deficient acetabulum may be augmented by placing local autogenous iliac osseous graft, or the ilium itself, over the head of the femur with the expectation that the added bone will function as a bearing surface. We analysed this bone obtained en bloc during subsequent surgery which was performed for degenerative osteoarthritis in three patients at 6, 25 and 30 years after the initial augmentation procedure. In each patient, the augmentation comprised of red cancellous bone covered on its articulating surface by a distinct layer of white tissue. Microscopy of this tissue showed parallel rows of spindle-shaped cells lying between linearly arranged collagen bundles typical of joint capsule. Biochemical analysis showed type I collagen, the principal collagen of joint capsule and bone, with no significant quantity of type II collagen, the principal collagen of cartilage. While the added bone produced by acetabular augmentation was durable, histological and biochemical analyses suggested that it had not undergone cartilage metaplasia. The augmented acetabulum articulates with the head of the femur by means of an interposed hip joint capsule.

Two collagen type IX gene polymorphisms that introduce a tryptophan residue into the protein’s triple-helical domain have been linked to an increased risk of lumbar disc disease. To determine whether a particular subset of symptomatic lumbar disease is specifically associated with these polymorphisms, we performed a prospective case-control study of 107 patients who underwent surgery of the lumbar spine. Patients were assigned to one of five clinical categories (fracture, disc degeneration, disc herniation, spinal stenosis without spondylolisthesis and spinal stenosis with spondylolisthesis) based on history, imaging results, and findings during surgery. Of the 11 tryptophan-positive patients, eight had spinal stenosis with spondylolisthesis and three had disc herniation. The presence of the tryptophan allele was significantly associated with African-American or Asian designation for race (odds ratio 4.61, 95% CI 0.63 to 25.35) and with the diagnosis of spinal stenosis with spondylolisthesis (odds ratio 6.81, 95% CI 1.47 to 41.95).

Our findings indicate that tryptophan polymorphisms predispose carriers to the development of symptomatic spinal stenosis associated with spondylolisthesis which requires surgery.

Aim: The aim of the project was to discover if bacteria were implicated in non-union of fractures of the tibia and femur, which had been treated with intramedullary nailing.

Method: 40 intramedullary nails removed from tibial and femoral fractures were retrieved for the purpose of the study. 20 of these nails were from fractures, which had successfully united and were removed for mainly anterior knee pain or discomfort at screw sites. These nails formed the control group for the project. 20 nails were removed from fractures which had failed to unite prior to further operative intervention such as exchange nailing or the application of an Ilizarov frame. These fractures had no clinical evidence of infection and formed the study group for the project. The nails were subjected to ultrasound in the research laboratory to dislodge adherent bacterial formed as biofilm from the surface of the nail. Using both standard culture techniques and non-culture techniques, any dislodged bacteria were isolated and identified. Non-culture techniques involved the use of specific monoclonal antibody labelled immunofluorescence microscopy. Isolated bacteria were tested for the sensitivities of commonly used antibiotics in orthopaedic practice according to NCCLS guidelines.

Results: We discovered that bacteria were detected in up to 70% of the nails removed from fractures, which had failed to unite, using both standard culture and non-culture techniques. Also, we discovered that bacteria were detected in up to 30% of the nails removed from fractures that had united. The organisms identified were mainly the coagulase negative staphylococcus epidermidis and the gram-positive anaerobe proprionibacterium acnes. The antibiotics gentamicin, erythromycin, cefotaxime and cefomandole performed poorly against the isolated bacteria. Vancomycin, ciproxin and fucidin however performed better.

Conclusion: Bacteria formed as biofilm on intramedullary nails may have a significant role in the development of non-union fractures treated by this method. The bacteria isolated showed worrying resistance to commonly used antibiotics in orthopaedic practice, in particular, those used as prophylaxis.

Objective: To analyse the incidence and gravity of reported complications that arise in spinal surgery and assess the comparative safety, or otherwise, of Endoscopic Laser Foraminoplasty.

Design: Prospective independently analysed study of complications arising during the six weeks following Endoscopic Laser Foraminoplasty was correlated and compared to a meta-analysis of reported data on complications in conventional spinal surgery.

Subjects: Nine hundred and fifty-eight procedures performed on 716 patients

Outcome measures: Occurrence of complications.

Results: The cohort integrity of operative and review records at six weeks after surgery was 100%. Twenty four complications occurred in 23 patients: nine cases of discitis (one infective) (0.9%), one dural tear (0.1%), one deep wound infection (0.1%), two patients suffered a foot drop (one transient) (0.2%), one myocardial infarction (0.1%), one erectile dysfunction (0.1%) and one post operative panic attacks (0.1%). MRI later demonstrated eight residual disc herniations (0.8%). The overall surgical complication rate was 1.6%. Meta-analysis of conventional spinal surgery reported overall complication rates for fusion (11.8%), decompression (7.6%), discectomy (6.0%) and chemonucleolysis (9.6%).

Conclusions: The complication rate of Endoscopic Laser Foraminoplasty is significantly lower than that reported following conventional spinal surgery (P < 0.01).

The thoracoscopic technic is a minimal surgical approach that minimizes the skin, muscle and ribs trauma without altering the effectiveness of the treatment.

This type of surgery has been gaining importance due to its advantages: excellent lighting, visualization and magnification. It offers an acute visual control during manipulation and dissection of delicate structures. We aim to assess the anterior release and the thoracic spine arthrodesis through thoracoscopic approach and measure the effectiveness and security of anterior thoracoscopic instrumentation in an experimental study in pigs.

The study was performed on 18 pigs which weighed between 40 and 60 kg. The surgical procedures were conducted at the Hospital Italiano in Buenos Aires. A thoracoscopic surgery was performed as an access to the spine.

The quality of the anterior release ranged significantly from cases in which the incision of the common anterior vertebral ligament could not be finished to cases in which more than 75% of the anterolateral disk circumference was released. In the subjective thoracoscopic assessment of the surgeon the screws were placed successfully in all The radiographic assessment confirmed the surgeon’s presumption, all the screws had been placed correctly. The rod presented complications in several cases.

The radiographic assessment showed that 40.6% (13 patients) of the disc spaces were pseudoarthrosic or with a delayed union. The macroscopic examination confirmed this finding and raised the number of pseudoarthrosic spaces up to 46.8% (15 patients) revealing 4 discs that still had a nucleus pulposus. The data were reinforced by histologic examination.

This histologic cuts were performed using the E & O method. The fibrous ring was clearly identified in the pseudoarthrosic cases as well as the processes of the osteochondral bone formation in its different phases of maturation.

It is very important to highlight that in our experience we had found a direct relationship between the quality of the disectomy, the fusion technique and the experience of the surgeon.

The surgical technique, the rod placement on the screws needs proper positioning and depth. The radiographic and microscopic examination confirmed that the posterior longitudinal ligaments was not damaged.

The thoracoscopic instrumentations in pigs using a rod and screws of third generation is a secure technique. It is essential the development of instrumentation which allows effective thoracoscopic distraction and compression.

We have used a culture system of human peripheral blood mononuclear cells (PBMC)as a source of osteoclast (OC) precursors and murine stromal cells to define the cytokine environment in which human OC form, and to determine the separate contributions of the stromal and haemopoietic elements. We designed a panel of reverse transcription-polymerase chain reaction (RT-PCR) primers that specifically amplify the respective murine or human mRNA species that correspond to cytokines and their receptors previously shown to promote or inhibit OC formation. Murine ST-2 cells and human PBMC were cocultured for up to 21 days in the presence of 1,25(OH) 2vitD3, dexamethasone and human macrophage-colony stimulating factor (M-CSF). OC formation was monitored by the appearance of cells that were positive for tartrate resistant acid phosphatase and able to form resorption lacunae on slices of dentine. We found that the ST-2 cells in these cultures expressed mRNA encoding a repertoire of many of the reported osteoclastogenic factors, as well as the recently described OC differentiation factor (ODF/RANKL). The stromal cells also expressed mRNA encoding osteoprotegerin (OPG), a potent inhibitor of OC formation. We found that agonists and antagonists of OC formation were expressed by both the stromal cells and the PBMC. RANK, the receptor for ODF/RANKL, was expressed only by the PBMC as were IL-1R2 and c-FMS. We identified three features of the cytokine environment that may be a characteristic of normal OC formation. Firstly, the ratio of mouse ODF:OPG mRNA was found to increase during the cocultures, consistent with a key role for ODF in the promotion by stromal cells of OC formation. Secondly, we found that mRNA encoding IL-1 and IL-17, as well as IL-6 and sIL-6R, were coordinately expressed by the PBMC. Thirdly, analysis of the culture medium showed that the PBMC secreted IL-1, IL-6 and TNF-alpha protein only in coculture with ST-2 cells during the first few days of osteoclast development. Similarly, prostaglandin E2, shown to synergise with ODF during OC development, was secreted only in cocultures. Together, these data show OC develop in a complex cytokine environment and suggest that haemopoietic cells provide signals to stromal cells during OC development. Work is in progress to extend these studies to human PBMC interacting with normal human osteoblasts.

Extensive osteolysis adjacent to implants is often associated with wear particles of prosthetic material. We have investigated if RANKL, also known as osteoprotegerin ligand, osteoclast differentiation factor or TRANCE, and its natural inhibitor, osteoprotegerin (OPG), may be important in controlling this bone loss.

Cells isolated from periprosthetic tissues containing wear particles expressed mRNA encoding for the pro-osteoclastogenic molecules, RANKL, its receptor RANK, monocyte colony-stimulating factor (M-CSF), interleukin (IL)-1β, tumour necrosis factor (TNF)α, IL-6, and soluble IL-6 receptor, as well as OPG. Osteoclasts formed from cells isolated from periprosthetic tissues in the presence and absence of human osteoblastic cells. When osteoclasts formed in the absence of osteoblastic cells, markedly higher levels of RANKL mRNA relative to OPG mRNA were expressed. Particles of prosthetic materials also stimulated human monocytes to express osteoclastogenic molecules in vitro.

Our results suggest that ingestion of prosthetic wear particles by macrophages results in expression of osteoclast-differentiating molecules and the stimulation of macrophage differentiation into osteoclasts.

Although arthroscopy of the hip is being carried out increasingly, little is known about the rate of associated complications. We describe a prospective study of 640 consecutive procedures in which a consistent technique was used. The overall complication rate was 1.6%. Complications, none of which was major or long-term, included transient palsy of the sciatic and femoral nerves, perineal injury, bleeding from the portal wounds, trochanteric bursitis and intra-articular breakage of the instrument. We believe that it is possible to undertake this operation safely using the technique described.

A 35-year-old man was seen with pain in the back of the knee. MRI showed a mass in the anterior cruciate ligament. Biopsy indicated mucoid degeneration. Arthroscopic resection of the ligament was carried out, with relief of symptoms.

In impaction grafting of contained bone defects after revision joint arthroplasty the graft behaves as a friable aggregate and its resistance to complex forces depends on grading, normal load and compaction. Bone mills in current use produce a distribution of particle sizes more uniform than is desirable for maximising resistance to shear stresses.

We have performed experiments in vitro using morsellised allograft bone from the femoral head which have shown that its mechanical properties improve with increasing normal load and with increasing shear strains (strain hardening). The mechanical strength also increases with increasing compaction energy, and with the addition of bioglass particles to make good the deficiency in small and very small fragments. Donor femoral heads may be milled while frozen without affecting the profile of the particle size. Osteoporotic femoral heads provide a similar grading of sizes, although fewer particles are obtained from each specimen. Our findings have implications for current practice and for the future development of materials and techniques.

Bone loss around replacement prostheses may be related to the activation of mononuclear phagocytes (MNP) by prosthetic wear particles. We investigated how osteoblast-like cells were regulated by human MNP stimulated by particles of prosthetic material.

Particles of titanium-6-aluminium-4-vanadium (TiAlV) stimulated MNP to release interleukin (IL)-1β, tumour necrosis factor (TNF)α, IL-6 and prostaglandin E₂ (PGE₂). All these mediators are implicated in regulating bone metabolism. Particle-activated MNP inhibited bone cell proliferation and stimulated release of IL-6 and PGE₂. The number of cells expressing alkaline phosphatase, a marker associated with mature osteo-blastic cells, was reduced. Experiments with blocking antibodies showed that TNFα was responsible for the reduction in proliferation and the numbers of cells expressing alkaline phosphatase. By contrast, IL-1β stimulated cell proliferation and differentiation. Both IL-1β and TNFα stimulated IL-6 and PGE₂release from the osteoblast-like cells.

Our results suggest that particle-activated mono-nuclear phagocytes can induce a change in the balance between bone formation and resorption by a number of mechanisms.

We have reviewed a series of 56 consecutive patients treated by the Ilizarov circular fixator for various combinations of nonunion, malunion and infection of fractures. We used segmental excision, distraction osteogenesis and gradual correction of the deformity as appropriate.

Treatment was effective in eliminating 40 out of 46 nonunions and all 22 infections. There were two cases of refracture some months after removal of the frame, both of which healed securely in a second frame. Correction of malunion was good in the coronal plane but there was a tendency to anterior angulation, often occurring in the regenerate bone rather than at the original fracture site, after removal of the frame. This was associated with very slow maturation of regenerate bone in some patients, occurring largely, but not exclusively, in those who smoked heavily.

Patients expressed high levels of satisfaction with the outcome, despite relatively modest improvements in pain and function, presumably because their longstanding and intractable nonunion had been treated. None the less, the degree of satisfaction correlated strongly with the degree of improvement in pain and function.

We emphasise the importance of a multidisciplinary team in the assessment and support of patients undergoing long and demanding treatment. The Ilizarov method is valuable, but research is needed to overcome the problems of delayed maturation of the regenerate and slow or insecure healing of the docking site.

Our aim was to determine whether in vitro studies would detect differences in the cellular response to wear particles of two titanium alloys commonly used in the manufacture of joint replacement prostheses. Particles were of the order of 1 μm in diameter representative of those found adjacent to failed prostheses.

Exposure of human monocytes to titanium 6-aluminium 4- vanadium (TiAlV) at concentrations of 4 x 10⁷ particles/ml produced a mean prostaglandin E₂ release of 2627.6 pM; this was significantly higher than the 317.4 pM induced by titanium 6-aluminium 7-niobium alloy (TiAlNb) particles (p = 0.006). Commercially-pure titanium particles induced a release of 347.8 pM. In addition, TiAlV stimulated significantly more release of the other cell mediators, interleukin-1, tumour necrosis factor and interleukin-6. At lower concentrations of particles there was less mediator release and less obvious differences between materials. None of the materials caused significant toxicity.

The levels of inflammatory mediators released by phagocytic cells in response to wear particles may influence the amount of periprosthetic bone loss. Our findings have shown that in vitro studies can detect differences in cellular response induced by particles of similar titanium alloys in common clinical use, although in vivo studies have shown little difference. While in vitro studies should not be used as the only form of assessment, they must be considered when assessing the relative biocompatibility of different implant materials.

1. The use of the Metals Research Macrotome for cutting 100 μ thick sections of fresh, unfixed specimens of arthritic human femoral heads and normal goat condyles is described.

2. A technique for isolating living cells from these slices by decalcification followed by enzymic digestion is reported.

3. The microscopic appearances of the fresh slices, the decalcified slices and the isolated cells as seen by incident or transmitted fluorescent lighting, by phase-contrast microscopy, by scanning electron microscopy and by histological and cytological techniques are illustrated.

4. These techniques might be applicable to the examination of biopsy specimens of pathological bone or to basic research on bone cells.

1. Methods for culturing cells isolated from slices of arthritic human or normal mammalian cancellous bone are described.

2. The capacity of the cultured cells to take up and hydroxylate labelled proline has been investigated.

3. Sections of the partially decalcified bone and of the isolated cells have been examined by transmission electron microscopy.

4. The possible significance of the results and observations are discussed. We are deeply grateful to Dame Janet Vaughan, who very kindly read this manuscript and made several valuable suggestions and criticisms. We are much obliged to Dr Sylvia Fitton-Jackson for her advice on the techniques of tissue culture and for giving us the composition of her chemically defined medium. Dr Palfrey kindly allowed one of us, M. J. Dickens, to learn transmission electron microscopy in his department at St Thomas's Hospital Medical School under the expert tuition of Mr G. Maxwell. Mr R. Hockhan and Mr M. Hepburn of the University of Surrey Structural Studies Unit helpfully instructed in the operation of the transmission electron microscope. Our special thanks are due to Mr E. P. Morris for his competent and enthusiastic technical assistance.

1. In seventeen cases of tuberculosis of the hip in children with severe destruction of the joint arthroplasty was done using full thickness skin from the abdominal wall as the interposing material.

2. The results, after a follow-up on the average of three years, show that one-third of the cases are very satisfactory, one-third are fair and one-third show no movement.

1. Convulsions causing fractures complicated the post-operative course of two patients after parathyroidectomy.

2. One patient with primary hyperparathyroidism and osteitis fibrosa developed tetany which was controlled with difficulty with the usual measures to correct hypocalcaemia. The convulsion occurred during hypomagnesaemia. This seemed the main immediate cause of symptoms and was easily corrected when recognised.

3. The second patient had been subjected to total parathyroidectomy for treatment of renal glomerular osteodystrophy. The complications were entirely due to hypocalcaemia and the usual treatment was inadequate until oral aluminium hydroxide was given.

4. Further experience shows that aluminium hydroxide can be a valuable addition to other measures for dealing with hypocalcaemia due to the "hungry bones" phenomena.

1. Contracture of parts of the quadriceps muscle is not uncommon and is often accompanied by tightness of the ilio-tibial tract. It is suggested that this may follow intramuscular injections.

2. Recurrent dislocation of the patella can be a consequence of this muscle contracture.

3. Division of the ilio-tibial tract and lengthening of the fibrotic elements of the quadriceps can prevent further dislocation and restore good function.

1. Frostbite in a child may be severe enough to destroy the cartilage cells of the epiphysial plate of a digit, and produce clinical deformity.

2. Both the direct effect of the freezing itself and the vascular changes secondary to such frostbite appear to cause necrosis of the growing epiphysis with destruction of the epiphysis and disappearance of the epiphysial line or plate. The disappearance of the epiphysial plate is obvious, but whether the epiphysis itself is actually destroyed and disappears or simply fuses with the metaphysis is a question now being studied.

3. It is suggested that the deformities may be helped by interphalangeal fusion of severely involved joints in the position of function, and phalanges that become angled into varus or valgus may be improved by open wedge osteotomy or epiphysiodesis of the side of the epiphysis still functioning.