In a retrospective investigation, the ability of modified tension band osteosynthesis to retain 45 reduced fractures of the patella and the functional end result was studied. Postoperatively, 24 patients were immobilized in plaster casts for 0-14 days and the remainder for 25-56 days. Postoperative radiographs revealed nine fractures (four transverse, three comminuted and two pole fractures) with fragment displacements exceeding 2-3 millimeters. Among these, three fractures had secondary dislocation and, further, one exactly reduced pole fracture dislocated. Operation was complicated with infection in four cases: two superficial wound infections, one subcutaneous fistula and one pyarthron. Operative release of adhesions was performed in five cases, two patients were patellectomized and one required a condyle prosthesis. At follow-up 18-80 months after the injury, 37 patients were examined clinically. Among 29 patients without concomitant injuries, seven patients were free of symptoms and 13 patients were without any pain. Free knee movement and quadriceps atrophy less than or equal to 1.5 cm was found in 17 patients. The modified tension band can retain adequately reduced transverse and comminuted fractures of the patella, probably also without plaster immobilisation. Dislocated fracture of the patella is a serious lesion, which must be treated with care.