Purpose: Surgeons performing hip resurfacing antevert and translate the femoral component anteriorly to maximize head/neck offset and reduce impingement. The anterior femoral neck is under tensile forces during gait similarly to the superior neck [6]. This study was designed to determine the risk of femoral neck fracture after anterior or posterior notching of the femoral neck.

Method: Forty seven fourth generation synthetic femora were implanted with Birmingham Hip Resurfacing prostheses (Smith & Nephew Inc. Memphis, USA). Implant preparation was performed using imageless computer navigation (VectorVision SR 1.0, BrainLAB, Germany). The prosthesis was initially planned for neutral version and translated anterior, or posterior, to create a femoral neck notch. The femora were fixed in a single-leg stance and tested with axial compression using a mechanical testing machine. This method enabled comparison with previously published data. The synthetic femora were prepared in eight experimental groups:two mm and five mm anterior notches, two mm and five mm posterior notches, neutral alignment with no notching (control), five mm superior notch, five mm anterior notch tested with the femur in 25° flexion and five mm posterior notch tested with the femur in 25° extension We tested the femora flexed at 25° flexion to simulate loading as seen during stair ascent. [3] The posterior five mm notched femoral necks were tested in extension to simulate sporting activities like running. The results were compared to the control group in neutral alignment using a one – way ANOVA:

Results: Testing Group Mean load to failure Significance (p-value) Anterior 2mm 3926.61 ± 894.17 .843 Anterior 5mm 3374.64 ± 345.65 .155 Neutral (Control) 4539.44 ± 786.44 – Posterior 2mm 4208.09 ± 1079.81 .994 Posterior 5mm 3988.06 ± 728.59 .902 Superior 5mm 2423.07 ± 424.17 .001 Anterior 5mm in 25° flexion 3048.11 ± 509.24 .027 Posterior 5mm in 25° extension 3104.62 ± 592.67 .038 Our data suggests that anterior and posterior two mm or five mm notches are not significantly weaker in axial compression. Anterior and posterior 5mm notches are significantly weaker in flexion/extension (p=0.027/ p=0.038). The five mm superior notch group was significantly weaker with axial compression supporting previous published data (p=0.001).

Conclusion: We conclude that anterior or posterior two mm notching of the femoral neck has no clinical implications, however five mm anterior or posterior femoral neck notching significantly weakens the femoral neck. Fracture is more likely to occur with stair ascent or activities involving weight bearing in extension. Hip resurfacing is commonly performed on active patients and five mm neck notching has clinically important implications.

The Taylor-Spatial fame is increasingly being used for complex corrective surgery. The frame and SPATIAL FRAME.COM internet software are powerful surgical tools. There are few paediatric cases in the literature. We present the results from The Royal Orthopaedic Hospital, Birmingham.

All consecutive patients having treatment with Taylor-Spatial Frames over a 3 year period were enrolled in the trial. All patients under 18 were included. The frames were applied to treat angular deformities and leg length discrepancies. The conditions included Blounts disease, post meningio-coccal septicemia, femoral growth arrest, fibular hemimelia and Olliers disease.

Seventeen frames were applied to thirteen patients. The average age was 9.3 (2–17). All radiographs were reviewed and the deformities recorded to provide reference for the correction. We recorded angulation and translation in three planes; anteroposterior, lateral and axial. This data was input to SPATIAL-FRAME.COM, the strut length changes were calculated and printed out. Osteotomies were performed depending on the pathology if necessary. The patients did not start the correction protocol until 5 days post-operatively. The average correction time was 28 days (5–80) All frames were left in situ until 3 corticies were visible in the regenerate. We recorded patient satisfaction, deformity correction, infection and bony union rates.

All frames provided full correction to within normal anatomical ranges, there were no cases of deep infection. 3 Superficial pin site infections were recorded and swabs confirmed staph aureus. Patients were very satisfied overall. One patient with bilateral Blounts disease had a gradual reoccurrence of the deformity after full correction initially. 1 case required bone grafting to improve regenerate production. Interestingly he had been taking anti-inflammatories. All cases achieved bony union.