Purpose

Femoroacetabular impingement syndrome (FAI) is a common cause of hip and groin pain in young adults. Physiotherapy and surgery have both been used to treat FAI syndrome, but there is no robust evidence of comparative effectiveness. UK FASHIoN compared the clinical and cost-effectiveness of arthroscopic hip surgery (HA) versus best conservative care in patients with FAI syndrome.

Background

There is a 20% dissatisfaction rate with knee replacements. Calls for tools that can pre-operatively identify patients at risk of being dissatisfied postoperatively have been widespread. However, it is unclear what sort of information patients would want from such a tool, how it would affect their decision making process, and at what part of the pathway such a tool should be used.

Background

Knee replacement surgery is currently facing three dilemmas: a high dissatisfaction rate; increasing demand with financial constraints; and variation in utilisation. A patient centred approach, usually achieved through shared decision-making, has the potential to help address these dilemmas. However, such an approach requires an understanding of the factors involved in patient decision-making. This is the first study examining decision-making in knee replacements that includes patients at different stages of decision-making – this is critical when considering decision-making as a process. We base our findings in a theoretical model, proposed by Elwyn et al, that highlights the distinction between deliberation and decision-making, and propose modifications to this model specific to knee replacement decision-making.

Background

Total Knee Replacement (TKR) is an effective treatment for knee arthritis. One long held principle of TKRs is positioning the components in alignment with the mechanical axis to restore the overall limb alignment to 180 ± 3 degrees. However, this view has been challenged recently. Given the high number of replacements performed, clarity on this integral aspect is necessary. Our objective was to investigate the association between malalignment and outcome (both PROMs and revision) following primary TKR.

Objectives

A patient-centred approach, usually achieved through shared decision making, has the potential to help improve decision making around knee arthroplasty surgery. However, such an approach requires an understanding of the factors involved in patient decision making. This review’s objective is to systematically examine the qualitative literature surrounding patients’ decision making in knee arthroplasty.

Introduction

There is an ever increasing demand for Randomised Controlled Trials (RCTs) in Trauma and Orthopaedic Surgery. Patient recruitment is often challenging. Among other factors, individual surgeon's preference is often quoted as a major obstacle. Collective equipoise based on present or imminent controversy in the expert medical community has been proposed as a solution, but could not help in everyday running of a trial. We wanted to develop a new trial eligibility assessment tool using the Collective Equipoise Principle.

Introduction

Simulation is increasingly perceived as an important component of surgical training. Cadaveric simulation offers an experience that can closely simulate operating on a living patient. We have explored the feasibility of providing cadaveric training for the whole curriculum for trauma and orthopaedic surgery speciality trainees, before they perform those operations on living patients.

Study aim

There is an ever increasing demand for quality clinical trials in surgery. Surgeons' co-operation and enthusiasm to participate are important, if not crucial in success of such studies, especially if they are multi-centred. Clinician's individual uncertainty (equipoise) about a case has been often cited as an ethical basis for inviting a patient to take part in a clinical trial. This study aims to establish current attitudes of surgeons participating in a national multi-centred randomised controlled trial and explores an on line tool for instant assessment of collective uncertainty (equipoise) for individual clinical cases eligible for a trial.

Background

Cam-type femoro-acetabular impingement (FAI) is increasingly recognised as a cause of mechanical hip symptoms in young adults. It is likely that it is a cause of early hip degeneration. Ganz et al have developed a therapeutic procedure involving trochanteric flip osteotomy and dislocation of the hip, and have reported good results. We have developed an arthroscopic osteochondroplasty to reshape the proximal femur and relieve impingement.

Background

Femoro-acetabular impingement (FAI) is increasingly recognised as a cause of mechanical hip symptoms in sportspersons. In femoro-acetabular impingement abnormal contact occurs between the proximal femur and the acetabular rim during terminal motion of the hip as a result of abnormal morphologic features involving the proximal femur (CAM) or the acetabulum (Pincer) or both (Mixed) leading to lesions of acetabular labrum and the adjacent acetabular cartilage. It is likely that it is a cause of early hip degeneration. Ganz developed a therapeutic procedure involving trochanteric flip osteotomy and dislocation of the hip, and have reported good results. We have developed an arthroscopic technique to reshape the proximal femur and remove prominent antero-superior acetabular rim thereby relieving impingement.

We investigated the blood flow to the femoral head during and after Resurfacing Arthroplasty of the hip.

In a previous study, we recorded the intra-operative blood flow in 12 patients who had a posterior approach to the hip and 12 who had a trochanteric flip approach. Using a LASER Doppler flowmeter, we found a 40% drop in blood flow in the posterior group and an 11% drop in the trochanteric flip group (p<0.001). The aim of this current study was to find out whether the intra-operative fall in blood flow persists during the post-operative period.

We therefore conducted a Single Positron Emission Tomography (SPECT) scan on 14 of the same group of patients. The proximal femur was divided into four regions of interest. These were the mid-shaft, proximal shaft, inter-trochanteric and head-neck regions. The data was analysed for bone activity and comparisons made between the two groups for each region of the femur. We found that the bone activity in the mid-shaft, upper-shaft, and head-neck regions was the same eleven months after the surgery irrespective of the approach to the hip. However there was higher activity in the trochanteric flip group in the inter-trochanteric region.

We conclude that the intra-operative deficit in blood flow to the head-neck region of the hip associated with the posterior approach does not seem to persist in the late post-operative period. We believe the reason for increased bone activity in inter-trochanteric region to be due to the healing of the trochanteric flip osteotomy.

The aim of this study was to assess the risks and benefits of mini-incision TKR. The limited exposure afforded by the small skin incision in the new technique of mini-incision TKR has the potential for increasing the risk of mal-positioning of components. Minor mal-positioning of components has the potential to increase polyethylene wear and may lead to early loosening and poor functioning of the TKR. The literature supports the concept that alignment within +/- 3 degrees of neutral mechanical alignment in the coronal plane is associated with a better outcome. If the mechanical axis falls outside this range it may have up to a 30% failure rate at 10 years.

We report the results of 166 mini-incision TKR that have been undertaken in 154 patients (96F; 58M; mean age 72; mean BMI 29; 96% OA) since November 2003. The pre-operative mechanical axis ranged from 8 degrees valgus to 15 degrees varus. Surgery was undertaken with a precise skin incision and a midvastus split approach. Specialised cutting blocks were used to facilitate a smaller incision. The prosthesis inserted was a cemented Zimmer NexGen TKR of either posterior stabilised or cruciate retaining form.

Long leg weight bearing alignment radiographs were available in 52% of patients. The mechanical axis was measured in the coronal plane and found to lie within +/- 3 degrees of neutral in 86% of patients. This compares favourably with the current literature which reports the mechanical axis falling within this range in between 72% and 85% of cases.

We believe the mini-incision TKR is a safe, reliable and reproducible technique offering substantial savings to the patient and health service without compromising accuracy.

Several factors have been identified that may affect outcome after total knee replacement (TKR). We performed a systematic review of studies that looked at the association of pre-operative factors and outcome after primary total knee replacement for osteoarthritis.

All study types that investigated TKR for osteoarthritis were considered except retrospective case-series. Studies that included patients undergoing revision TKR were excluded if they did not provide separate results for primary and revision knee replacement. Any patient factor that was measured in the pre-operative period was included.

The factors measured included age, sex, race, income, body mass index (BMI), medical or joint co-morbidity, level of education, disease specific scores and their subcategories and general health scores. Studies that recorded outcome measures were only included if evidence of validation for use after total knee replacement was available.

We identified 590 studies purporting to evaluate TKR for OA. Of these, 25 studies were retrieved for in-depth consideration and 10 were found to meet the inclusion criteria. Most of these were cohort studies that used some form of regression analysis.

The results showed that the strongest and most consistent correlations were between pre-operative pain scores, pre-operative function scores, co-morbidity and post-operative function scores. Age, gender and level of education were not significant predictors of outcome. However, even the best models could only predict 36% of the variance in outcome.

Understanding which factors influence outcome the most will be of great benefit to patients and those who plan and deliver healthcare.

We used a laser Doppler flow-meter with high energy (20 m W) laser (Moor Instruments Ltd. Milwey, UK) to measure the blood flow to the femoral head during resurfacing arthroplasty.

Twenty-four hips were studied; 12 underwent a posterior approach and twelve a Ganz's trochanteric flip osteotomy. The approach was determined according to surgeon preference. Three patients were excluded, The exclusion criteria were previous hip surgery, history of hip fracture and avascular necrosis (AVN). All patients had the hybrid implant with cemented femoral component.

During surgery a 2.0mm drill bit was passed via the lateral femoral cortex to the superior part of the head neck junction. The position was confirmed using fluoroscopy. The measurements were taken during five stages of the operation: when the fascia lata was opened (baseline), at the end of soft tissue dissection, following dislocation of the hip, after relocation back into the socket, after inserting the implants prior to closing the soft tissues and, finally, at the end of soft tissue closure.

The results were analysed and the values were normalised to a percentage of the baseline value. We found a mean drop of 38.6 % in the blood flow during the posterior approach and a drop of 10.34% with the trochanteric flip approach. The significant drop occured between the baseline (1st stage) and the end of the soft-tissue dissection (2nd stage). In both groups the blood flow remained relatively constant afterwards.

Our study shows that there is a highly significant drop in blood flow (p<0.001) during the posterior approach compared with the trochanteric flip approach.

Thromboprophylaxis remains a controversial issue and many disagree about the optimum method or even if it is required at all.

We present a new method of performing meta-analysis incorporating studies with both experimental and observational study designs. We have developed a model that compares study cohorts of several different methods of thromboprophylaxis with a simulated matched control group whose variance helps to adjust for bias. This allows meaningful comparisons between studies and treatments that have not been directly compared.

We performed a systematic review of the literature from 1981 to October 2004. Studies where more than one method of prophylaxis was used were excluded from analysis. For each individual method of prophylaxis, data was extracted, combined and converted to give estimates of the rates of symptomatic, proximal DVT, fatal PE and major bleeding events. We identified 1242 studies of which 203 met the inclusion criteria for further analysis. This represented the results of over fifty thousand studied patients. We expressed the results for the different prophylactic methods as odds ratios compared to no prophylaxis.

All methods showed a beneficial effect in reducing VTEs apart from stockings and aspirin which showed an increase in the number of PE events. These results are particularly interesting when viewed from the standpoint of an individual NHS hospital trust that performs around 500 hip and knee replacements per year. Over a 5 year period, the more effective methods of prophylaxis prevented between 15 and 40 symptomatic DVTs and up to 3 fatal PEs compared to no treatment. However, they cause between 8 and 40 more major bleeding events. We do not know the proportion of these major bleeding events that are fatal.

Introduction: Injuries to the ligamentum teres are being recognised more often with developments in imaging, such as MR arthrography, and the increasing use of hip arthroscopy. But they are difficult to diagnose, and it is not clear how best to treat them. Little is known about the mechanism of injury, nor the potential impact on hip stability of such injuries. The relationship between capsular and ligamentous contributions to stability has not been investigated.

Methods: We examined the movement of the ligamentum teres in intact, fully reduced, cadaveric hip specimens by trans osseus arthroscopy. The movement of the ligamentum teres was captured with video throughout the excursion of the hip joint. The influence of restraining capsular structures was determined by sequential transection and repeat excursion testing. Ligamentum teres injuries were generated by extreme movements, and compared with clinically observed injuries.

Results: The action of the ligamentum teres was successfully recorded in by video. The ligament was found to be the principal restraint to external rotation in extension and abduction. Injuries generated by forced rotation in this position resembled those seen in clinical practice.

Conclusion: Knowledge of the action of the ligamentum teres will improve our understanding of injury to this structure. It helps to identify described mechanisms which should raise suspicion of such an injury, and may help to design investigation and treatment protocols.

Introduction: Pain and mass lesions around hip resurfacing are reported with increasing frequency. The aetiology is unknown but reaction to metal wear debris and mechanical impingement have both been suggested. We are aware of a group of our patients with significant pain following resurfacing. We sought to correlate metal ion levels with X-ray findings and any local soft tissue reaction around the prosthesis.

Methods: Patients with significant groin pain following hip resurfacing were identified from routine clinics. Blood was tested for cobalt and chromium levels using inductively coupled mass spectrometry in all patients. Cup abduction angle and femoral stem version were estimated from plain radiographs. Patients underwent ultrasound scan (USS) of the affected hip joint. Bilateral prostheses were excluded to avoid confounding.

Results: 47 unilateral painful hip resurfacings (24 female) were identified. USS was performed in 42 patients and was abnormal in 25 (15 female). Abnormalities ranged from simple joint effusion with or without synovial thickening, through to cystic masses in the posterior joint and solid masses related to the ileopsoas tendon similar to the appearances previously described in pseudotumours.

A two sample t-test demonstrated cobalt and chromium ion levels were significantly higher in patients with abnormalities on USS (p=0.038, p=0.05 respectively), patients with normal USS were more likely to have a retroverted femoral component (p=0.01).

Discussion: We describe two groups of patients with a painful hip resurfacing: those with raised metal ions and local soft tissue reaction, and those with lower metal ions and no soft tissue reaction. The retroverted stems in the second group could cause an iatrogenic cam-type impingement. Metal ion levels are useful to guide further imaging. Raised levels should prompt investigation for a soft tissue abnormality with either USS or MRI, lower levels suggest investigation should look for mechanical impingement with imaging such as CT.

Introduction: Chondral lesions are the second most common pathology encountered during hip arthroscopy. Microfracture is a simple and effective technique to treat chondral lesions with proven long term results in the knee. However, there is little evidence to confirm the ability of microfracture to produce repair tissue in hip joint.

Methods: Patients with acetabular chondral defect treated with microfracture during primary arthroscopy and who had a subsequent hip arthroscopy enabling visualisation of the treated chondral defect were included in the study. Over a three year period 185 patients had microfracture for treatment of full thickness chondral defect. 11 patients (8 males and 3 females) with a mean age of 35 years (range 17–54 years) who had revision hip arthroscopy form the study population. The size of chondral defect was measured at the time of primary arthroscopy. Microfracture was performed using arthroscopic awls with a standard technique. Postoperatively a strict rehabilitation protocol was followed. The extent and quality of repair tissue was assessed by visual inspection at second look arthroscopy

Results: All patients had chondral lesions confined to the antero-superior aspect of the acetabulum with an associated labral tear. None had diffuse osteoarthritis. The average defect measured 180 mm2 (range 50–300). The mean time interval between primary and revision arthroscopy was 12 months. Excluding one failure the overall percent fill of the defects was 95% (range 75 – 100) with good quality cartilage.

Discussion: Only one other series has reported on the macroscopic results of microfracture in the hip. Our series agrees with the results of those authors. These similar results from 2 centres confirm that arthroscopic microfracture is an effective treatment for acetabular chondral lesions in carefully selected patients.

Introduction: Accurate templating prior to hip replacement requires that the magnification of the radiograph is known. This magnification is usually measured using a scale marker ball or disc of known diameter, but this method is inaccurate when the marker is not precisely positioned in the coronal plane of the hips.

Our aims were to design a novel scale marker which does not require such precise positioning, and to compare the accuracy of this new marker with a standard single ball marker.

Methods: The new marker consists of two separate markers: one behind the patient’s pelvis, the other at the front. It can be shown that the radiographic magnification of such markers is consistently related to the magnification of the hips.

The posterior marker consists of a 75x75cm square foam mat, incorporating multiple 25.4mm metal rods arranged in series down the centre. The anterior marker is made from five 25.4mm steel balls, linked in series at 20mm intervals. The mat is positioned just underneath the patient’s pelvis as they lie supine for their radiograph. The five balls are placed in the midline over the patient’s suprapubic region, and the x-ray is then taken. The radiographic dimensions of the ball and rod which are located between the hips are then measured. The magnification of the hips may then be calculated from these dimensions using a simple equation.

To validate the new “double” marker, it was compared with a conventional single marker ball. 74 hip arthroplasty patients undergoing routine radiographic follow up were recruited. Both the new double marker and the single marker were applied at the time of x-ray, the magnification according to each was calculated, and these were compared to the true radiographic magnification as determined from the known dimensions of the prosthesis. All markers were positioned by independent radiographers trained in their use.

Results: The correlation between true and predicted magnification was excellent using the double marker (r=0.90), but only moderate for the single marker (r=0.50). The median error of the single marker was 4.8%, but only 1.1% for the double marker (p< 0.001). The reliability of the double marker as a predictor of true magnification was very good (intraclass correlation coefficient, ICC=0.89), but was poor for the single marker (ICC=0.32). The accuracy of the double marker was unaffected by the patient’s body mass index. The inter and intraobserver variability of the new method were both excellent (ICC> 0.94).

Discussion: The double marker method is significantly more accurate and reliable than the single marker method when used in a clinical setting, as it does not rely on precise positioning of the marker by the user. We believe that this technique may become the gold standard method of calculating radiographic hip magnification in clinical practice.

Introduction: Clinical communication and research across centres will be facilitated by an easy to use and reliable method to describe lesions within the hip. This requires a system for describing location and a system for describing pathology. We present a hip mapping system for describing location, which has been used to map more than 2000 therapeutic hip arthroscopies to date and tested for ease of use and inter-observer reliability.

Method: The articular surfaces of acetabulum and femoral head are divided into zones. The femoral head has a medial zone around the fovea (A) approximately 2.5 cm in diameter. Lines radiating from the fovea at 90-degree intervals divide the remaining head into equally sized posterior, superior, anterior and inferior zones (B, C, D, E respectively).

The acetabular surface is divided radially into five zones (A, B, C, D, E) starting postero-inferior (A) and ending antero-inferior (E). Each zone is further divided in half into an outer and inner zone, forming ten zones in total i.e Ai, Ao, Bi, Bo.etc.

This study was performed during therapeutic hip arthroscopy of 41 patients. Five surgeons took part in the study. After gaining access into the hip joint one of the surgeons identified three small intra-articular features (marks, small defects or blood clots) as X, Y and Z to some or all of the other 4 surgeons. Each of the other surgeons examined the hip independently without Discussion: and recorded the location on a hip map. If two surgeons had observed a point, this provided one pair to assess agreement; three or four surgeons provided three or six pairs respectively. Each observation of a point by a pair of surgeons (a point-pair) provided one opportunity for assessment of agreement.

Results: In total 103 points were mapped by two, three or four surgeons giving 286 point-pairs for assessment. In 263 cases (92%), the pair of surgeons were in agreement, designating the point as within the same zone. On 23 (8%) occasions, there was disagreement but always across a boundary between adjacent zones. Disagreements were more common about points on the femoral head (12) than on the acetabulum (11). Seven of these were the boundary between femoral zone A and one of the other zones (B, C, D). Disagreements in acetabulum occurred equally at each radial boundary (A/B-2, B/C-3, C/D-2, D/E-2) but only rarely between inner and outer acetabular zones (2 point-pairs).

All surgeons reported that they found the system easy to use. There was no difference in the level of disagreement between more and less experienced surgeons or a learning effect with time.

Conclusion: Inter-observer reliability of this mapping system was 92%. Disagreements all occurred at boundaries between zones especially on the femoral head where zones are difficult to define in the absence of landmarks. This study supports the use of a zone based mapping system in clinical practice.