Novel custom made composite spacer for first-stage revision total hip replacement in the presence of extensive acetabular/femoral bone loss with abductor deficiency.

A two-stage revision total hip replacement (THR) remains the gold standard for treating chronic periprosthetic joint infection. The goals for the first stage are twofold: (1) remove infected tissue/implants, obtaining tissue samples for culture; (2) deliver local antibiotics and maintain hip function with a prosthesis with antibiotic-loaded acrylic cement. With extensive bone loss prefabricated spacers are not sufficient, therefore customised spacers are required. The current technique, coating cephalomedually femoral nail in cement, is complex, time consuming, functions poorly and causes wear debris from excessive friction at the femoral/acetabular articulation. We report a technique to create a custom made composite spacer using a short femoral nail, standard Exeter femoral stem (Stryker), Trident acetabular cup (Stryker) and polymethyl methacrylate (PMMA) bone cement with antibiotics. This technique restores hip biomechanics and gives a stable articulation, even in the presence of abductor deficiency, due to dual mobility bearings.

Lateral Intercondylar Ridge: Is it a reliable landmark for femoral ACL insertion?: An anatomical study.

BACKGROUND: Incorrect femoral tunnel placement is the most common cause of graft failure during Anterior Cruciate Ligament (ACL) Reconstruction. A reliable landmark can minimize errors. AIM: To identify whether the Lateral Intercondylar Ridge (LIR) is a consistent anatomical structure and define its relationship with the femoral ACL insertion. MATERIALS AND METHODS: Phase 1: we studied 23 femoral dry bone specimens macroscopically. Using a digital microscribe, the medial surface of the lateral femoral condyle was reconstructed (3D) to evaluate whether there was an identifiable bony ridge. Phase 2: 7 cadaveric specimens with intact soft tissues were dissected to identify the femoral ACL insertion. A 3D reconstruction of the femoral ACL insertion and the surface allowed us to define the relationship between the LIR and the ACL insertion. RESULTS: All specimens had a defined LIR on the medial surface of the lateral femoral condyle. The ridge was consistently located just anterior to the femoral ACL insertion. The ACL footprint was present in the depression between the ridge and the Inferior Articular Cartilage Margin (IACM). The mean distance from the midpoint of the IACM to the LIR was 10.1 mm. CONCLUSIONS: This is the first study to use the microscribe to digitally reconstruct the medial surface of the lateral femoral condyle. It shows that the LIR is a consistent anatomical structure that defines the anterior margin of the femoral ACL insertion, which guides femoral tunnel placement. Our findings support the ruler technique, which is a commonly used method for anatomic single bundle ACL reconstruction.

Novel technique to accurately measure femoral diameter using a Thomas splint.

INTRODUCTION: During surgical management of femoral shaft fractures, difficulties arise when treating patients with narrow femoral diaphyseal canals, such as young patients and those with dysplastic femurs secondary to underlying pathology. Accurate pre-operative assessment of the femoral diaphyseal canal diameter would allow the surgeon to plan surgical technique and ensure appropriate equipment was available, such as narrow, unreamed or paediatric sized nails. TECHNIQUE: When secured to the patient both longitudinal rods of the main Thomas Splint component lie parallel with the femoral shaft and horizontal to the radiographic x-ray plate. The diameter of these rods are 13mm (Adult and paediatric). Using the calibration tool, we calibrate the diameter of the Thomas Splint to 13mm, accurately measuring any further detail on that radiograph, such as the diaphyseal canal diameter. CONCLUSION: Accurate knowledge pre-operatively of radiographic measurements is highly valuable to the operating surgeon. This technique can accurately measure femoral canal diameter using the Thomas splint, negates the requirement for a calibration marker, is reproducible, easy to perform, and is indispensible when faced with a patient with a narrow femoral canal in a diaphyseal femoral fracture. (181 words).

Bizarre parosteal osteochondromatous proliferation: a locally aggressive benign tumor.

BACKGROUND: Bizarre parosteal osteochondromatous proliferation (BPOP) is a benign lesion of bone, and numerous questions remain unresolved regarding its etiology, diagnosis, and treatment. QUESTIONS/PURPOSES: We present the Scottish Bone Tumour Registry experience of this rare lesion. PATIENTS AND METHODS: We performed a retrospective analysis of the Scottish Bone Tumour Registry records. Histologic specimens were reexamined by a musculoskeletal pathologist. Radiographs were reevaluated by a musculoskeletal radiologist. RESULTS: From 1983 to 2009, 13 cases (13 patients; six male, seven female) were identified. Their ages ranged from 13 to 65 years. All patients presented with localized swelling. Pain was present in five. Antecedent trauma was present in two. Nine lesions affected the hand, three the foot, and one the tibial tuberosity. Twelve lesions were excised and one was curetted. There were seven recurrences of which six were excised. One lesion recurred a second time and was excised. There were no metastases. Radiographs showed densely mineralized lesions contiguous with an uninvolved cortex. Cortical breakthrough was present in one case and scalloping in another. Histologic analysis characteristically showed hypercellular cartilage with pleomorphism and calcification/ossification without atypia, bone undergoing maturation, and a spindle cell stroma. CONCLUSIONS: BPOP is a rare benign lesion that probably is neoplastic, with no gender predilection, and affecting patients over a wide age range. Previously trauma was considered an etiologic factor, but this no longer seems to be the case. The rate of recurrence was 50%, which may indicate a more extensive resection is required for this locally aggressive lesion. No metastases were reported. BPOP should not be mistaken for, or treated as, a malignant tumor. LEVEL OF EVIDENCE: Level IV, retrospective case series. See Guidelines for Authors for a complete description of levels of evidence.

Diagnostic accuracy of static graf technique of ultrasound evaluation of infant hips for developmental dysplasia.

INTRODUCTION: Ultrasound examination of infant hips is a widely used and accepted tool for the diagnosis and monitoring of developmental dysplasia of the hip. Its use and timing is still a focus of debate and its diagnostic accuracy has not been fully investigated. METHOD: We have compared the ultrasound findings by the Graf technique with radiographic appearance (acetabular index) at 6 months of age. RESULT: The negative predictive value of Ultrasound for DDH was 98% and was unaffected by the timing of the examination. The specificity and accuracy of the examination increased with age and was highest at 3 months of age. CONCLUSION: Ultrasound examination of the infant hip by the static Graf technique is a safe and effective screening tool for the evaluation of DDH.

Femoral neck resorption following hybrid metal-on-metal hip resurfacing arthroplasty: a radiological and biomechanical analysis.

INTRODUCTION: With the resurgence of resurfacing hip arthroplasty complications such as femoral neck fracture and thinning have been identified. We therefore conducted a radiological and biomechanical evaluation of factors affecting femoral neck resorption following resurfacing hip arthroplasty (RHA). METHODS: We retrospectively reviewed 61 resurfacing hip arthroplasties in 53 patients with a minimum of a 2-year follow-up. Data regarding age, gender, body mass index, indication for surgery, and component size was obtained from case records. Radiographic measurements were made from standardised digital AP pelvic radiographs. The neck shaft angle, stem shaft angle, and the varus-valgus femoral stem alignment were calculated. Changes in abductor/body moment arm, hip ratio, and cup-to-neck ratio were calculated from the pre-op, immediate post-op and 2 year post-operative radiographs. RESULTS: Femoral neck thinning was identified in 98% of cases (60/61) and was greater than 10% in 59% (39/61). The mean change in component-to-neck ratio was 0.12 (0-0.44). No significant relationship was found between the amount of femoral neck resorption and patient age, BMI, gender, diagnosis, component size or orientation. A significant positive correlation was found between a change in abductor moment arm and femoral neck resorption (R = 0.575; p < 0.01). We also calculated that approximately one-third of the change in CNR could be explained by a change in abductor moment arm. From this we formulated the Pillai-Joseph equation to calculate projected thinning at 2 years from the initial post-operative radiograph (CNR difference = 0.094 × AMA difference + 0.129). CONCLUSIONS: RHA significantly alters hip biomechanics and this may result in altered loading patterns with adaptive remodelling causing neck thinning. In order to minimise neck thinning care must be taken not to increase the abductor moment arm.

Clopidogrel in Orthopaedic patients: a review of current practice in Scotland.

BACKGROUND: Clopidogrel bisulfate is an antiplatelet agent used to prevent ischaemic events in patients with vascular disease. Current guidelines recommend withholding clopidogrel for 7 days pre-operatively. However these are not based on orthopaedic patients. We therefore decided to survey current orthopaedic practice to see whether this complied with available clinical data. METHOD: A questionnaire was sent to all orthopaedic consultants in Scotland. Four haematology departments, and the manufacturers, were contacted to ask for their recommendations, and a database search was performed. RESULTS: 140 questionnaires were sent with a 60.7% response. 84.7% of respondents have encountered patients on clopidogrel. Of those, 13.9% did not routinely stop it, and 86.1% stopped it 5-21 days pre-operatively (47.2% at 7 days).45.9% had a unit policy on stopping clopidogrel, and the majority (69.4%) did not consult their haematology department prior to instituting their policy.Increased peri-operative bleeding was the most reported complication (22.6%). However this was only noted in those who stopped clopidogrel greater-than 7 days pre-operatively. Haematology advice ranged from continuing clopidogrel peri-operatively to stopping it 7 days pre-operatively and starting low-molecular-weight-heparin for thrombo-prophylaxis. The manufacturers suggested stopping clopidogrel 7 days pre-operatively. An internet search did not reveal any data on the effect of clopidogrel peri-operatively in orthopaedic patients. DISCUSSION: Recommendations on stopping clopidogrel have evolved from studies conducted on patients undergoing cardio-thoracic surgery. There is no data available on the effect of clopidogrel in orthopaedic practice. Our survey indicates that increased bleeding has not been found in patients who continue clopidogrel peri-operatively. Almost half of respondents complied with current recommendations, stopping clopidogrel 7 days pre-operatively. However there remains a lack of consensus amongst orthopaedic surgeons.Currently elective patients should stop clopidogrel 7 days pre-operatively, and emergency patients should stop clopidogrel on admission, however their operation should not be delayed due to clopidogrel usage.