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

Stable fractures of the ankle can be successfully treated non-operatively by a below-knee plaster cast. In some centres, patients with this injury are routinely administered low-molecular-weight heparin, to reduce the risk of deep-vein thrombosis (DVT). We have assessed the incidence of DVT in 100 patients in the absence of any thromboprophylaxis. A colour Doppler duplex ultrasound scan was done at the time of the removal of the cast.

Five patients did develop DVT, though none had clinical signs suggestive of it. One case involved the femoral and another the popliteal vein. No patient developed pulmonary embolism. As the incidence of DVT after ankle fractures is low, we do not recommend routine thromboprophylaxis.

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.

Aim: This study compares the MRI scan with clinical diagnosis, and looks at the reliability of both these against the gold standard of arthroscopic diagnosis, in disorders of the knee.

Materials and methods: The patients were from the knee specialist unit of a tertiary referral centre seen and operated by the senior author , over a two year period. This is a retrospective study. The total number of patients in this study was 58(n=58) , with ages ranging from 18–63 years. The results were obtained using statistical formulae, which calculated the sensitivity , Specificity , accuracy and the positive and negative predictive values of the MRI scan and that of clinical diagnosis .

Results: The MRI scan was found to be significantly sensitive in diagnosis of medial meniscal lesions, 96% (95% Confidence interval 89–100), it was also found to be significantly specific in diagnosis of lateral meniscal, 90% ( 95% CI, 81–98) and ACL lesions 94% (95% CI,87–100). The MRI scan had poor sensitivity and specificity for articular cartilage lesions.

The sensitivity of clinical diagnosis for medial and lateral meniscus and ACL lesions was found to be less than 90%. Clinical impression was found to be significantly specific for lesions of ACL and the articular cartilage.

The negative predictive value of the MRI scan was found to be significantly high (> 95%), for lesions of the medial and lateral meniscus and the ACL.

Conclusion: The MRI had a poor diagnostic value in diagnosing and quantifying articular cartilage (chondral) lesions. Clinical diagnosis had a lower sensitivity as compared to MRI in diagnosis of medial meniscal lesions but was more specific in diagnosing cruciate and articular cartilage pathology. The reliability of a high negative predictive value for the MRI scan in ruling out medial meniscus, lateral meniscus and ACL lesion was demonstrated. Therefore, a ‘normal’ scan can be used to exclude lesions. thus sparing patients from expensive and unnecessary surgery and also freeing up valuable theatre time.

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.

We describe a patient who sustained a widely displaced, high-energy, mid-shaft clavicular fracture in association with brachial plexus damage. The distal fragment was subsequently found to have penetrated the thoracic cavity. We describe the treatment of this rare injury with a successful outcome.

Introduction: (OCD) is characterized by bone necrosis and softening of the overlying cartilage, which may separate and displace. It is thought to be secondary to trauma, ischaemia or abnormal epiphyseal ossification. Management remains controversial during the early stages of the disease. Surgery for advanced chondral lesions with loose bodies however remains a challenge. Options that include periosteal graft and autologous chondrocyte transplantation have been used with variable degrees of success. This study investigates the efficacy of these techniques and the use of mesenchymal stem cells to treat advanced chondral lesions found in OCD in animal models.

Materials and Methods: A full thickness articular cartilage defect (6mm long, 3mm wide and 1mm deep) was created in the weight-bearing surface of medial femoral condyle in 22-week old NZW rabbits. A total of 90 knees were randomly divided into 3 groups as follows: 1) Transfer of cultured chondrocytes 2) Transfer of cultured periosteum-derived MSCs and 3) Repair by periosteal graft with their contralateral knees as control. The rabbits were allowed to move freely in their cages. The rabbits were sacrificed at 2, 6, 12, 24 and 36 weeks post-operatively. The healing of the defects was assessed by gross examination and histological grading and subjected biomechanical testing.

Results: Gross and histological examination at 36 weeks post operation (Wakitani et al grading), the mean score for Group 1 is 2.5, Group 2 is 2.3 and Group 3 is 4.5 with control group of 8.9 in terms of cell morphology, matrix staining, surface regularity, thickness of repaired cartilage and integration of cartilage to adjacent host. Biomechanically by indentation test, Group1 had value of 0.22 MPa, Group 2 0.20 MPa, Group 3 0.16 MPa and Control group of 0.12 MPa.

Conclusion: The findings suggested that cultured chondrocytes and mesenchymal stem cells had comparable enhancing effect of the repair of chondral defect in advanced OCD

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.

Video-assisted thoracoscopic surgery (VATS) has been in use since the 1980s for surgery of the spine. Initially it was used for anterior release of the thoracic spine in order to facilitate posterior instrumentation. With increasing experience, it has been applied to perform definitive correction and instrumentation. Video-assisted thoracoscopic spine surgery allows the surgeon to perform anterior thoracic spine operations with fewer levels of instrumentation, reducing the crankshaft effect and removing the morbidity associated with thoracotomy. From 1996 to November 2000, our center performed 19 such operations. 18 of them were completed successfully endoscopically and one was converted to an open procedure. An initial group of 10 patients underwent thoracoscopic anterior release and fusion followed by same day posterior instrumentation and fusion. Subsequently, 6 patients underwent anterior discectomies, fusion with instrumentation via thoracoscopic approach.

For the initial 10 patients, the average operative time was 190 minutes. The average post-operative correction was 62 % and blood loss was 350 mLs. For the 6 patients who underwent anterior discectomies, fusion and instrumentation via the thoracoscopic approach, the average operative time was 360 minutes; average post-operative correction was 70% and blood loss was 400 mLs.

Complications encountered were minor and included one case ofcontralateral pneumothorax, one patient complained of transient limb numbness which resolved within 6 weeks. It is our conclusion that thoracoscopic anterior spinal surgery, though with learning curve, a safe and effective procedure.

Objective: To determine the efficacy and safety of pamidronate combined with intramedullary rodding in improving bone mineralisation and reducing fracture incidence in children with osteogenesis imperfecta (O.I.).

Methods: A prospective pilot, open study was performed in which intravenous pamidronate was administered at 1.5 mg/kg bi-monthly to 12 children with O.I., over 18 – 28 months. The children were serially monitored for symptoms, anthropometric measurements, fracture incidence, biochemical assessments of calcium metabolism, bone mineral density (BMD), serum alkaline phosphatase (ALP), urinary N-telopeptides, and spine X-rays. Intra-medullary rodding of fractures were performed with when there was definite angulation of bones.

Results: The number of fractures decreased from 4 to 0.85 fractures/year during pamidronate therapy (p< 0.05). After 18 months of treatment, there was significant improvement in Areal BMD z scores of the lumbar spine from −2.38 to −1.76 (p < 0.05) and in the Volumetric BMD, which increased from 0.06 to 0.09 g/cm3 (p < 0.05). At 18 months, urine N-telopeptide levels (bone resorption marker), decreased from 439.7 to 222.3 BCE/Cr (p < 0.05), and serum ALP (bone formation marker) from 225.0 to 143.5 U/L (p < 0.05), reflecting reduced bone turnover. This may represent a net reduction in bone resorption, and provides a biochemical explanation for the increase in bone mineralisation. Height standard deviation scores were not affected, and there were no significant adverse effects.

Conclusion: 18 months cyclical pamidronate is effective in improving bone mineralisation, and reducing fracture incidence in O.I. Pamidronate therapy, which was safe, and when combined with intra-medullary rodding, can potentially improve the quality of life by improving mobility and preventing post-fracture deformities, thus offering new hope for children afflicted with OI.

Introduction: Surgery in patients with neuromuscular scoliosis is aimed at improving truncal balance, facilitating sitting, prevention of progression of the curve and preservation of respiratory function.

Patients and Methods: This was a retrospective study of surgical results in a group of 24 patients with minimum follow up of 2 years an average post-operative follow up of 5 years (2–9 years) with neuromuscular scoliosis due to varying aetiologies. The aetiologies included SMA (7), CP (6), Duchenne (5), Congenital Myopathies (3), Spina Bifida (2) and Paraspinal Neuroblastoma (1).

Results: The average age at surgery was 10.6 years, the average duration was 4hrs 25mins with an average blood loss pf 1.1 liters. An average ICU stay was 1–2 days and stay in hospital is 11 days. The curves ranged from 25–103° (average 75.6°) pre-operative and we were able to obtain a correction of 56%. In all but 2 of our patients we were successful in preventing deterioration of respiratory function and all our patients could at least sit without support post-operatively. Our complications included only one deep infection (necessitating implant removal), 1 rod breakage and 2 patients with UTI. There were no significant respiratory complications in post-operation.

Conclusion: Spinal surgery in patients with neuromuscular scoliosis is safe and prevents deterioration of respiratory and improve truncal balance and hence quality of life.

We carried out a prospective study in order to establish to what extent the intra-articular evaluation undertaken during arthroscopy of the knee differed between surgeons. Two senior specialist registrars and a consultant orthopaedic surgeon with a special interest in knee surgery were involved. A total of 78 knee arthroscopies (78 patients) was studied. Arthroscopy was first carried out by the trainee and then by the senior author (ACWH). The intra-articular evaluation during the arthroscopy was recorded independently by a third person in the operating theatre. Data were collected to record variations in examination under anaesthesia, the morphology and pathology of the menisci and anterior cruciate ligament and the state of the articular surfaces.

The overall interobserver variation was 20% in all categories. We question the published results of intra-articular evaluation during knee arthroscopy when surgeons of different levels of experience are involved in a single study.

Forty-seven patients over the age of 55 years with a displaced fracture of the ankle were entered into a prospective, randomised study in order to compare open reduction and internal fixation with closed treatment in a plaster cast; 36 were reviewed after a mean of 27 months. The outcome was assessed clinically, radiologically and functionally using the Olerud score.

The results showed that anatomical reduction was significantly less reliable (p = 0.03) and loss of reduction significantly more common (p = 0.001) in the group with closed treatment. Those managed by open reduction and internal fixation had a significantly higher functional outcome score (p = 0.03) and a significantly better range of movement of the ankle (p = 0.044) at review.

We recruited 89 patients who had hip or knee replacements to assess the performance of below-knee graded compression stockings. The pressure gradients generated by the stockings were measured and all patients had venography of the ipsilateral leg.

We found that 98% of stockings failed to produce the ‘ideal’ pressure gradient (± 20%) of 18, 14 and 8 mmHg from the ankle to the knee, while 54% produced a ‘reversed gradient’ on at least one occasion during the course of the study. The overall rate of deep-venous thrombosis was 16.7%. Stockings which produced reversed gradients were associated with a significantly higher incidence of deep-venous thrombosis (p = 0.026) than those with the correct gradient (25.6% v 6.1%). This suggests that the performance of graded compression stockings can be improved if reversed pressure gradients are detected and prevented.