Minimally invasive medial hip approach for femoral head fixation: How much can we see and what is the anatomical at risk? - A cadaveric injection study.

INTRODUCTION: Most Pipkin I and II femoral head fractures are treated with either an anterior or a posterior approach. A medial hip approach is commonly used in children, and some surgeons have suggested it for femoral head fixation. The objectives of this study were to identify the structures at risk with the medial hip approach and to demonstrate the areas of the femoral head exposed using this approach.

METHODS: The first part of this study involved vascular injection conducted in four fresh human cadavers using the medial hip approach. The surgical technique was described and the structures at risk, mainly arteries, were identified. The second part was done in 14 hips to identify and measured the maximum exposure area of the femoral head with the medial hip approach.

RESULTS: The structures at risk with the medial hip approach were the medial femoral circumflex artery (MFCA) after it branches from the deep femoral artery and runs posteromedially across the femoral neck medial to the iliopsoas tendon and the deep branch of the MFCA lies over the posterior hip capsule. The femoral head exposure area in anterior view with anteroinferior articular cartilage exposure was 4.57 ± 1.09 cm2 . In the medial view with the hip in internal rotation and in external rotation, the inferomedial articular cartilage exposure was 2.50 ± 1.52 cm2 and 6.48 ± 2.29 cm2 , respectively, and the combined area of exposure was 9.49 ± 2.86 cm2 . In the posterior view, the posteroinferior articular exposure was 1.69 ± 1.16 cm2 . The medial hip approach allowed visualization of the small area of the posteroinferior articular cartilage in all specimens. The percentages of visualization of the femoral head articular cartilage in anterior view, medial view and posterior view were 50.07% ± 13.53, 45.56% ± 12.76 and 18.07% ± 11.27%, respectively.

CONCLUSIONS: The structures at risk with the medial hip approach is the MFCA along the anterior acetabular rim and the deep branch on the posteromedial aspect of the femoral neck. It is an alternative which provides excellent access in Pipkin I and some part of Pipkin II, but it requires that the MFCA be protected by the use of meticulous surgical techniques.