Gordon et al. [9] suggested that tears of the gluteal tendons are likely to be responsible for calcifications seen radiographically in some patients. In patients with tears of the gluteus medius and/or minimus tendons reactive sclerosis and bone proliferation can be observed particularly at the anterior edge of the sclerotic area [10]. In a study of Steinert et al. [11] including 150 patients, 90 % of patients with trochanteric surface irregularities larger than 2 mm on conventional radiographs have a lesion of the abductor tendons on MR images (positive likelihood ratio of 5.8). 98 % of patients with trochanteric surface irregularities larger than 2 mm on conventional radiographs have peritendinous fluid changes around the gluteus medius and minimus tendon insertions (positive likelihood ratio of 17.5). These findings are of importance to orthopedic surgeons and rheumatologists. In many institutions, a preoperative MR before arthroplasty of the hip is performed when an abductor tendon lesion is suspected clinically. If abductor tendon pathologies are detected on MR images (Figs. 13.3, 13.4, 13.5, and 13.6), the orthopedic surgeon may change the surgical approach. In the presence of an abductor tendon tear, a possible posterior approach is chosen and the abductor tendons are reattached during the implantation of the hip arthroplasty. In case of no tendon pathology, a minimal invasive anterior approach without touching the abductor tendons is performed [12]. Many clinicians, even orthopadic surgeons, seem to underestimate tears of the abductor tendons as a cause of hip pain and treatment option for hip pain. Cormier et al. [13] showed that almost half (45 %) out of 459 French orthopedic surgeons, who were contacted by mail, were not aware of the possibility that tendon tears can occur in the rotator cuff of the hip. Only 13 % (60/459) had performed surgical repair of a gluteal tendon which had been correctly diagnosed preoperatively. However, surgical treatment of gluteal tendon tears has been shown to be very effective [14]. Lequesne and colleagues [14] showed a complete or total remission of symptoms in 90 % after the surgical treatment of abductor tendon tears. Kagan [15] reported seven patients treated with success by gluteus medius tendon repair. Moreover, Miozzari et al. [16] demonstrated that 75 % of all patients with late repair of abductor dehiscence after transgluteal approach for hip arthroplasty were satisfied.

There are also a relationship between gluteal tendon abnormalities at the insertion onto the greater trochanter and bursitis as previously been reported [17, 18]. Bird et al. [18] described 24 patients with trochanteric pain of which 8 % showed a bursitis comparable to the cases in this present study where increased bursal fluid was seen in 9 % of all patients (14/150). Kingzett-Taylor et al. [5] demonstrated that 14 of 35 patients (40 %) with a tendinopathy or an abductor tendon tear also had increased amounts of bursal fluid. However, this does not necessarily mean that there is a symptomatic bursitis because bursal fluid is a nonspecific reaction to a number of different abnormalities. Blankenbaker et al. [19] commonly found bursal fluid and peritrochanteric edema in asymptomatic hips (88 %).