Calcific tendinitis in the posterior proximal thigh as a self-limited condition: pathogenic role of inflammatory responses

OBJECTIVE: Calcific tendinitis occurs rarely in the posterior proximal thigh. We investigated whether it is self-limited and how the natural course of the disease progresses. METHODS: We treated 6 patients with no surgical intervention, and analyzed laboratory and radiological findings in the followup period of more than one year (average followup, 2.5 yrs). RESULTS: Although tendinitis was severe, rapid relief was observed within 2 weeks (average 5 days). Radiological features including extraskeletal calcifications did not change within 2 weeks, and then improved by 6 weeks. Four of 6 cases showed abnormal laboratory variables. All elevated white blood cell counts and C-reactive protein levels improved within one week with clinical resolution. In comparison with time course of the symptoms, changes in the radiological findings over time appeared not to be parallel with the clinical course, but laboratory progression appeared to correspond well with clinical resolution. CONCLUSION: Inflammatory responses to hydroxyapatite crystals may play a role in the pathogenesis of symptoms of calcific tendinitis in the posterior proximal thigh, most of which are self-limited.