RAMUS PUBIS INSUFFICIENCY FRACTURES AFTER TOTAL HIP ARTHROPLASTY: PHYSIOLOGICAL AND BIOMECHANICAL CONSIDERATIONS

Although uncommon, pubic ramus fractures are described in patients who have undergone total hip arthroplasty (THA). We describe two females with superior ramus pubis insufficiency fractures following THA. We consider the physiological and biomechanical aspects of those fractures, e.g. that the superior ramus pubis has the highest load stress on the pelvis (as has already been proved in a three-dimensional finite element model). Also being discussed are risk factors (intrinsic and extrinsic) for stress fractures and the management of insufficiency fractures. Both women suffered osteoporosis, obesity, and had a semisedentary lifestyle — all of which are known risks factors for insufficiency superior ramus pubis fracture to occur in a location which proved as a "weak link" zone after THA. Many of these fractures are undetected, mainly due to the lack of awareness of medical practitioners who attribute the clinical symptoms to other diseases; however, the differential diagnosis of groin pain within the first years following THA should include pubic ramus insufficiency fractures.