The aim of this study was to assess the frequency of the quadriceps tendon ruptures in patients with end stage renal disease (ESRD) on dialysis, analyze the connection of the findings with disorders of calcium and phosphate metabolism, and evaluate the role of ultrasound in diagnosis of this complication. We examined 175 patients aged between 17 and 73 years (average: 50 years) with ESRD on dialysis (77 males, 98 females). Average length of dialysis treatment was 60 months ranging from 0.5 to 230 months. During the observation period, three of the 175 patients had spontaneous bilateral quadriceps tendon ruptures, which developed simultaneously or within a short interval of time (1.7 %).The mean age of patients with ruptures was 40 years, and the mean duration of dialysis was 76.7 months. In all cases, quadriceps tendon ruptures developed with insignificant trauma.One patient developed simultaneous bilateral rupture; in two other patients, contralateral rupture happened in 3 weeks and 2 months respectively. All detected ruptures were localized just proximal to the superior pole of the patella. Two out of the six ruptures were accompanied by the avulsion fracture of the superior pole of the patella. In three cases, quadriceps tendon was calcified. All three patients had significant secondary hyperparathyroidism (SHPT) with intact parathyroid hormone (iPTH) over 2.500 pg/ml (263 pmol/l). Hyperphosphatemia and increased calcium—phosphorus product were detected in all cases.Groups of patients with tendon rupture showed significantly greater iPTH and phosphorus levels than all the others (р=0,005 and p=0,048 accordingly). Ultrasound examination detected enlargement of one to three parathyroid glands with the total volume from 1.0 to 1.21 см³. Ultrasound is a non–ionizing, inexpensive, and highly informative method for diagnosis of quadriceps tendon ruptures in patients with ESRD. Our data confirms leading role of the high level of the iPTH and hyperphosphatemia in development of the spontaneous tendon ruptures in dialysis patients. Evaluation of the parathyroid glands and correction of the SHPT are necessary in prevention of this serious complication.
