Recurrent patellar instability is common in young and active patients. Medial patellofemoral ligament (MPFL) reconstruction with a single bundle hamstring graft is one method of surgical treatment for this problem. This is a retrospective case series of patients who underwent MPFL reconstruction by a single specialist knee surgeon between January 2009 and July 2014. Data was collected prospectively for the purpose of service evaluation. Recorded data included gender, age, length of rehabilitation, complications, Knee Injury and Outcome Score (KOOS) and International Knee Documentation Score (IKDC). Data is expressed as mean (range). 108 knees (103 patients) were identified (56 female, 52 male) with a mean age of 24.5 years (12–58). Mean length of rehabilitation was 3.2 months (0–11 months). Three patients required further revision surgery for recurrent instability. KOOS and IKDC scores improved from 44 (4–86) and 38 (2–81), respectively before surgery, to 77 (49–100) and 69 (37–95) after rehabilitation. MPFL reconstruction with a single bundle hamstring graft produces a marked improvement in knee function with a low recurrence of instability.

Introduction

High flexion knee arthroplasties have been designed to allow up to 155 degrees flexion and enable high flexion activities such as kneeling and squatting. To date randomised controlled trials have shown no difference in range of movement (ROM) between high flexion and standard designs.

Background

The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use.

Introduction

The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use.

Stable ankle fractures can be successfully treated non-operatively with a below knee plaster cast. In some European centres it is standard practice to administer thromboprophylaxis, in the form of low molecular weight heparin, to these patients in order to reduce the risk of deep venous thrombosis (DVT).

The aim of our study was to assess the incidence of DVT in such patients in the absence of any thromboprophylaxis. We designed a prospective study, which was approved by the local ethics committee. We included 100 consecutive patients with ankle fractures treated in a below knee plaster cast. At the time of plaster removal (6 weeks), patients were examined for signs of DVT. A colour doppler duplex ultrasound scan was then performed by one of the two experienced musculoskeletal ultrasound technicians.

We found that 5 patients developed a DVT. Two of these were above knee, involving the superficial femoral vein and popliteal vein respectively. The other three were below knee. None of the patients had any clinical symptoms or signs of DVT. None of the patients developed pulmonary embolism. Of these five patients, four had some predisposing factors for DVT.

The annual incidence of DVT in the normal population is about 0.1%. This can increase to about 4.5% by the age of 75. DVT following hip and knee replacement can occur in 40-80% of cases. Routine thromboprophylaxis may be justified in these patients. However, with a low incidence of 5% following ankle fractures treated in a cast, we believe that routine thromboprophylaxis is not justified.

Introduction: To quantify the magnitude and incidence of haemodynamic changes that occurs during the fixation of extracapsular proximal femoral fractures when using either intra-medullary or extra-medullary fixation device.

Methods: A prospective group of 31 patients with extra-capsular proximal femoral fractures were randomised to either fixation using an extra-medullary compression hip screw or an intra-medullary hip screw. All patients received a general anaesthetic adhering to a standardised anaesthetic protocol including invasive blood pressure monitoring and arterial blood gas sampling. Trans-oesophageal Doppler probe and monitor was used to record pre-operative hypovolaemia and peri-operative changes in cardiac output, stroke volume and corrected flow time (FTc – a reflection of left ventricular end diastolic pressure) during placement of implants.

Results: 77% of patients were hypovolaemic preoperatively, which was corrected with an average of 439 mls of colloid replacement fluid. Application of the extra-medullary CHS produced no change in haemodynamic function. However on insertion of the IMHS we found a statistically significant reduction in stroke volume, cardiac output and FTc without changes in pulse rate or mean arterial pressure. The changes were transient with normal cardiac function returning by 5 mins post operatively.

Conclusion: The transient fall in cardiac function during insertion of the intramedullary hip screw may be caused by fat embolism entering the venous circulation. As these changes are not detected with standard non-invasive monitoring we would recommend that intramedullary devices be used with caution in elderly patients who tend to have poor physiological reserve.

AIM: To investigate the relationship between patient variables and surgeons’ grade and experience on one hand and re-operation and mortality rates at six months on the other hand.

Method: Seven hundred and sixty-one patients with proximal femoral fractures (PFF) (463 intracapsular fractures, 286 extracapsular fractures, and 12 subtrochanteric fractures) were treated surgically between April 2005 to October 2007. The level of experience among trainees was quantified as the number of PFF they had fixed or replaced as the first surgeon, from the start of their training at Senior House Officer level to the beginning of the study period.

Logistic regression model was used to investigate the relationship between mortality and re-operation at six months and case mix variables (age, ASA grade, fracture types, pre-fracture residence, and mobility and activity level), and management variables (days to operation, the grade of the surgeon and supervision level). Mann-Whitney test was used to compare the level of experience among trainees in the group of patients who died or required re-operation at six months.

Results: At six months, the mortality rate was 24.2% (184) and the re-operation rate was 3.8% (29).

The logistic regression model used to predict six months mortality was highly significant (X2=166.6 [24df], p< 0.0001). It showed that age, ASA grade and pre-fracture activity level were strongly associated with mortality at six months. Patients operated on by a trainee without the consultant being scrubbed were 1.8 times (p< 0.05) more likely to die at 6 months. (Odds ratio of 1.8 with 95% confidence interval of 1.15 to 2.75). Re-operation at six months could not be predicted by these factors.

Regarding patients operated on by trainees, there was no significant difference in the level of experience among trainees who operated on patients who died or who required re-operation at six months compared to those who did not.

Aim: To compare the acute haemoglobin level drop following hip fracture fixation with IMHS and CHS at James Cook University Hospital and assess whether the surgeon’s seniority has any effect on the amount of blood loss in these two procedures.

Methods: Trauma data base was searched for all IMHS procedures performed from January 2002 till March 2007 both included and CHS procedures performed from January 2007 till March 2008 both included.

There were 159 CHS procedures and 146 IMHS procedures. 137 CHS and 123 IMHS procedures fulfilled the blood testing and transfusion criteria.

Haemoglobin levels were used as an indication for blood loss attributable to surgery. The difference between the last level of haemoglobin checked preoperatively and the first post operative level performed between 12–48 hours postoperatively is calculated. Cases where blood transfusion was carried out preoperatively without further preoperative haemoglobin check were excluded, so were cases receiving intra or post operative blood transfusion prior to the defined postoperative haemoglobin check was carried out.

Results: SPSS 13.0 statistical package was used to analyse the results. Levene’s test proved equality of variances of blood loss within the two groups of patients undergoing one of the two procedures, P=0.5. Hence, Independent Samples T test was applicable and showed that patients undergoing an IMHS procedure dropped their haemoglobin levels by 2.96 g/dl. While, those undergoing a CHS procedure dropped their haemoglobin levels by 2.32 g/dl. The 0.64 g/dl difference in haemoglobin drop was statistically significant at 5% significance level with 95% CI (0.27 to 1.01), P=0.001.

The surgeons’ grades were classified into three groups as: Consultants, Registrars and Senior House Officers. Levene’s test again proved the variances of haemoglobin drop within each group to be homogeneous. Hence a One-Way ANOVA test was carried out showing that the differences in haemoglobin drop were not statistically significant when comparing the three groups of surgeons to each other. This was true for both IMHS and CHS procedures.

Conclusion: Patients undergoing a CHS procedure drop their haemoglobin levels by 0.64 g/dl less than those undergoing an IMHS procedure. The surgeon’s seniority does not make difference to the amount of haemoglobin level drop following either of the two procedures.

We recommend the use of CHS for stable fractures and reserve the IMHS for the unstable ones due to the increased blood loss with IMHS procedures.

Introduction: Classification systems are useful in research and clinical practise as it provides a common mode of communication and evaluation. Tibial pilon injuries are a complex group of fractures, whose classification and radiological assessment in clinical practise remains undetermined.

Methods: 50 CT scans and radiographs of tibial pilon fractures were evaluated independently by 6 orthopaedic surgeons, comprising 3 consultants, 2 registrars and 1 research fellow. Fractures were classified according to ruedi allgower, AO, Topliss et al. Each surgeon was given a period of 48 hours to review copy of the original article as well as written and diagrammatic representations. Assessment was done on two occasions, 4 weeks apart. The kappa coefficient of agreement was calculated with SPSS to determine interobserver reliability and intraobserver reproducibility of the classification systems. The evaluator was blinded as to treatment and functional outcome. Each evaluator was also asked to decide upon the fracture management based on the classification types and was compared with the actual management.

Result: The interobserver agreement for ruedi allgower, Ao and Topliss et al., was fair, moderate and poor respectively. The intraobserver agreement for ruedi allgower, AO and Topliss et al., classifications was moderate at best. There was poor agreement amongst observers regarding definite management plan based on these classification systems.

Discussion: The interobserver agreement was directly proportional to the familiarity and inversely proportional to the specificity of the classification system. The intraobserver agreement improved with experience. CT scan helped in delineating the fracture segments accurately but did not significantly affect inter or intraob-server agreement.

Conclusion: Existing classification systems help in understanding the pathoanatomy of osseous part of tibial pilon fracture complex. However, Soft tissue injury forms an integral part of this complex. Without inclusion of soft tissue injury, these classification systems have limited role in definitive management.

Introduction: Previous studies have demonstrated the value of the tip-apex distance (TAD) and the location of the screw in the femoral head in predicting cut-out. Similarly surgeons’ volume has been shown to affect mortality and morbidity in various surgical specialties, including in trauma and orthopaedics.

Aim: To determine whether re-operation due to cut out at six month can be predicted using TAD, location of the screw and fracture type; and whether the experience of the surgeon is important.

Methods: Logistic regression was used to analyse data collected retrospectively from 241 patients with extracapsular fractures (Jensen’s modification of Evans’ classification: Class I – 90, Class II – 93 and Class III – 58), treated with a dynamic hip screw, classic hip screw or intramedullary hip screw from April 2005 to October 2007.

Results: There were 7 cut outs (2.5%) requiring re-operation within 6 months – 1 in the consultant group and 6 in the trainee group,. The model used was statistically significant (X2=23.6 [13df], p< 0.05). The tip-apex distance was a strong predictor (p< 0.05) of cut-out requiring re-operation at six months. The odds of the patient requiring re-operation due to cut out increases by a factor of 1.2 for each millimetre increase in the TAD. Location of the hip screw and fracture type were however not significant predictors. The first surgeon was a consultant in 54 cases and trainee in 187 cases. There was no statistically significant difference in re-operation rate due to cut out between patients operated on by consultants compared to trainees.

Conclusion: The TAD is a strong predictor of cut out requiring re-operation at 6 months. No difference was found in our series in re-operation rate due to cut out among cases performed by consultants compared to trainees.

Idiopathic anterior knee pain (AKP) is common in adolescents and young adults. Most believe that the origin of the problem lies in the patello-femoral joint. Hamstring tightness has also been attributed as an important cause.

The aim of our study was to compare biometric parameters in patients with idiopathic AKP and controls. We also wanted to assess whether there was a difference in the relative electromyographic (EMG) onset times of the medial and lateral hamstrings.

We prospectively recruited patients with idiopathic anterior knee pain in the age group 11 to 25. Patients, but not the control population, had AP, lateral and skyline radiographs taken to rule out other pathology.

We had 34 patients (60 knees) with a minimum one year follow up. There was no difference in the symptoms of patients who attended physiotherapy as compared to those who did not. Patients with knee pain had significantly more hip external rotation (63 deg) as compared to the control (47 deg) group (p=0.001). Patients also had significantly more hamstring tightness (p=0.04).

Surface EMG was recorded (17 patients and controls each) from the medial and lateral hamstrings during 3 repetitions of a maximal voluntary isometric contraction exercise with the knee at 45° of flexion. The lateral hamstrings contracted 48.7 m.sec earlier than the medial hamstrings in patients as compared to controls.

AKP is a multifactorial and self-limiting disorder. Earlier contraction of the lateral hamstrings may cause tibial external rotation and contribute to the symptoms. Our data suggests that physiotherapy did not significantly alter the course of the condition. We believe that increased hip external rotation may contribute to the symptoms by increasing medial facet stress.

Introduction: Several institutes in continental Europe and the US now prescribe low molecular weight heparin for patients with ankle fractures being treated in a below knee plaster cast. Jorgensen et al reported an incidence of deep venous thrombosis (DVT) of up to 20% in patients treated in a cast. However, their study included patients with variable diagnoses, ranging from tendon ruptures to fractures. The aim of our study was to assess the incidence of DVT in patients with ankle fractures that have been treated conservatively in a below knee cast.

Method: We performed an ultrasound scan on patients with conservatively ankle fractures at the time of removal of the cast. The same ultrasound technician performed all the scans. The local regional ethics committee had approved this study.

Results: So far we have performed an ultrasound scan on 98 patients with ankle fractures. We are likely to complete the study in November 2006 (120 patients). We have encountered only 2 below knee DVTs (2.04 %). None of them involved the popliteal vein. Both patients were completely asymptomatic and were full weight bearing in the cast. A repeat scan showed no evidence of progression. None of the patients had an above knee DVT or a pulmonary embolism.

Discussion: The risk of deep venous thrombosis is said to be higher in patients with a plaster cast because of the decreased ability of the calf muscles to pump the venous blood back to the heart. Though some studies have indicated an incidence of up to 20%, the incidence in our population was only about 2%Thus, DVT is a rare event in patients with ankle fractures. Though it is a serious event, its rarity does not justify a blanket prophylaxis regimen for all patients with ankle fractures.

Introduction: Poor proprioception and imbalance between quadriceps and hamstrings have been suggested as causes for anterior knee pain. The aim of our study was to compare the proprioception of patients with anterior knee pain to a normal population and to compare the activity of quadriceps and hamstrings using electromyography (EMG) in the 2 groups.

Methods: Patients and controls between the ages 11–25 yrs were recruited into the study. The proprioception (stability index) of the patients and controls was tested using the Biodex stability system. This computerised system tests the ability of a person to balance his/her own body on a platform that moves in various directions. Surface EMG was recorded from the quadriceps and hamstrings during this test. EMG was also recorded as the patients and controls stepped onto a 20cm step. EMG activity was normalised to levels elicited during maximal isometric contractions.

Results: 18 patients and 27 controls were recruited.

We found no significant difference between the groups in the EMG intensity of vastus lateralis relative to biceps femoris, or vastus medialis relative to vastus lateralis, during the balance test or during the step up task (Mann Whitney U test all p> 0.05). We did not find any difference in the proprioceptive abilities of the two groups

Conclusion: We found no significant difference between the groups in the intensity of muscle contraction of the hamstrings relative to the quadriceps, i.e. no evidence for an imbalance in the patients. However the temporal relation between the two needs further investigation.

The aim of this study was to determine whether there is a difference in the functional outcome between fixed and mobile bearings in total knee arthroplasty.

120 patients were randomized (computer generated) to receive either a fixed or mobile bearing P.F.C. Sigma total knee replacement. 96 patients were needed to detect a 20° difference in range of motion (ROM) with a significance level of 0.05 and a test power of 0.97. Oxford knee score (OKS) and ROM were assessed independently before and one year after surgery.

Mean ROM and Oxford knee score before and at one year after surgery for both groups are shown as preliminary results for 70 patients (follow-up expected to be completed by March 2006):

There is no statistically significant difference in the mean ROM at one year and in change in ROM between the two groups (p=0.53 and p=0.21 respectively). The findings were similar for Oxford Knee Score at one year and change in Oxford Knee Score (p=0.45 and p=0.82). There was no early aseptic loosening in either group.

The one year results suggest that there is no significant difference in functional outcome measured as ROM and Oxford Knee Score between the two types of bearing. Further follow-up will be carried out to detect any differences in the long term outcome.

The purpose of this study was to determine contact patterns in cementless acetabular cups using a novel computed tomography (CT) scan analysis technique. Eighteen embalmed cadaveric hemipelvis specimens were randomly assigned to receive one of three cup designs. A custom CT platform was designed to optimize imaging of the acetabular cups. After cup implantation, specimens were mounted on the platform and imaged in a spiral CT scanner. Contact analysis was preformed using custom-developed imaging software. The hemisphere, dual geometry and spiked cup designs analyzed using this CT analysis technique demonstrate differences in the amount and distribution of bone pros-thesis contact.

The purpose of this study was to determine contact patterns in cementless acetabular cups using computed tomography (CT) scan analysis.

Eighteen embalmed cadaveric hemipelvis specimens were randomly assigned to receive a hemispherical cup, a dual geometry cup, or a spiked cup. After radiographic templating, an experienced orthopaedic team prepared the specimens and implanted the acetabular cups. A custom CT platform was designed to optimize imaging of the acetabular cups. After cup implantation, specimens were mounted on the platform and imaged in a spiral CT scanner. Contact analysis was preformed using custom-developed imaging software. Contact was defined as a bone-prosthesis distance of 0.5 mm or less.

The mean amount of cup contact was 40.4% (SD=8.2%) in the hemisphere group, 24.7% (SD=2.3%) in the dual geometry group, and 29.7% (SD=9.5%) in the spiked group. Colour mapping of the bone-prosthesis gap was used to identify contact/non-contact regions along the acetabular contour for all cup designs.

Preliminary work with this CT analysis technique demonstrates differences in the amount and distribution of contact in the acetabular cup designs. Future work will involve development of an imaging phantom to clarify error, use of the technique with different cup designs and reaming techniques, and comparison of this technique with conventional CT scan techniques.

This study outlines a novel CT analysis technique for quantitatively determining bone-prosthesis contact for cementless acetabular cups.

The hemisphere, dual geometry and spiked cup designs analyzed using this CT analysis technique demonstrate differences in the amount and distribution of bone prosthesis contact.

Funding: Smith and Nephew

Aim: To investigate in vitro the mechanical stability of a locking compression plate (LCP) construct in a simulated diaphyseal fracture of the humerus at increasing distances between the plate and bone.

Materials & Method: A series of biomechanical in vitro experiments were performed using Composite Humerus Sawbone as the bone model. Osteotomy created in the mid-diaphyseal region. A 10mm osteotomy gap was bridged with a 7-hole 4.5 stainless steel plate with one of four methods: a control group consisted of a Dynamic Compression Plate applied flush to the bone and three study groups which comprised of a LCP applied flush to the bone, at 2mm and at 5mm from the bone. Standard AO technique used with locking head screws used for LCP fixation. Static and dynamic loading tests performed in a jig with the bone model fixed both proximally and distally. Samples were subjected to cyclical compression, compression load to failure, cyclical torque and torque to failure. Plastic deformation and failure was assessed. Scanning electron microscopy of the plate and screw surface allowed detailed inspection of micro-fracture in areas of fatigue.

Results: Consistent results were achieved in LCP constructs in which the plate was applied at or less than 2mm from the bone. When applied 5mm from the bone the LCP demonstrated significantly increased plastic deformation during cyclical compression and required lower loads to induce construct failure.

Conclusion: In our laboratory model a significant decrease in axial stiffness and torsional rigidity becomes evident at a distance of 5mm between plate and bone.

Purpose of the study: To determine usefulness of skyline x-ray in diagnosis of patellofemoral osteoarthritis.

Materials and Methods: 50 patients scheduled to undergo knee surgery, had standard antero-posterior, lateral and skyline x-rays of their affected knee. At operation, their patellofemoral joints were graded into two groups according to presence or absence of osteoarthritis. Their lateral and skyline x-rays were also graded into the same two groups, according to presence or absence of patellofemoral osteoarthritis. The two x-ray views were then compared individually against operative findings.

Results: The skyline view had sensitivity of 79% (95% confidence intervals (C.I.) 66% to 93%) and specificity of 80% (95% C.I. 62% to 98%). The lateral view had sensitivity of 82% (95% C.I. 69% to 95%) and specificity of 65% (95% C.I. 44% to 86%).

Conclusion: There was no statistically significant difference between the two x-ray views in terms of sensitivity and specificity in the diagnosis of patellofemoral osteoarthritis of the knee joint. Hence, we cannot recommend the skyline view as a routine radiological investigation in all cases of suspected patellofemoral osteoarthritis.

Clinical investigations and tests need to be validated by studying their inter-observer and intra-observer errors, but there has been no documentation of such verification in diagnostic knee arthroscopy. We performed a prospective study to find out to what extent the findings in knee arthroscopy differ between two different surgeons.

Two senior specialist registrars (M.S. and A.J.) who took part in this study worked with the senior author (ACW) for a period of eight and seven months respectively. A total of 78 knee arthroscopies admitted from routine waiting list were studied. The specialist registrar first performed arthroscopy when the supervising consultant stayed away from the operating room. His findings were recorded on a proforma by an independent third person before the consultant returned to the operating room and repeated the EUA and arthroscopy without prior knowledge of the trainee findings. Findings from the consultant arthroscopy were then recorded separately on the same proforma.

The following findings were recorded:

Examination under anaesthesia

The inter-observer variations in diagnostic knee arthroscopy were found to be high. Given the seniority and experience of the two trainee senior registrars involved in the study, and allowing for the Hawthorne effect, the results of the study cast doubt on this procedure being performed un-supervised. It also questions the validity of any therapeutic intervention based on the findings of un-supervised arthroscopies.