Introduction 4 29 2 5 9 15 17 23 24 26 2 5 8 9 15 17 2 5 17 15 9 17 14 27 28 The aim of this study was to evaluate the clinical and radiographic results of our minimally invasive surgical treatment of intraarticular fractures of the calcaneus at 2–10 years postoperatively. We then compared our results to the results of both open and minimally invasive surgical techniques found in the literature. Material and methods Patients 27 14 28 Examination 25 3 17 18 3 30 Statistical analysis For statistical analysis the Fisher’s exact test and the Chi-square test were used. Perioperative treatment and surgical technique After a calcaneal fracture was diagnosed, the lower leg was evaluated. If the soft tissue was in good condition, primary surgery performed. In cases of severe swelling with potential soft tissue damage NSAIDs, local cryotherapy and active movement exercises determined the course of therapy. Once the soft tissue was in good condition, surgery was performed. The patient was placed prone on the traction table under general anaesthesia or spinal anaesthesia without arrest of blood supply. After application of the calcaneus wire for traction in the dorso-cranial plane, the varus or valgus malaligment of the back foot was corrected with the wire positioned orthogonally to the longitudinal axis of the calcaneus. To achieve correct placement, the surgeon pulled at the traction bow with the knee bent along the longitudinal axis of the calcaneus. The subsequent traction in the plantar plane was performed with the leg stretched. Once placed in the proper orientation, the traction bow was connected to the retaining jig of the traction table (traction of 20 kg). The surgeon then held the heel of the patient with both hands and applied compression both medially and laterally with his thenar muscle to reduce the main medial and lateral fragments. 1 1 2 2 28 Fig. 1 left side right side  Fig. 2 left side right side  25 3 Fig. 3 left side right side left side right side  Results Fifty-five of the 88 (62.5%) patients suffered exclusively from calcanal fractures. Thirty-three of the 88 (37.5%) patients had multiple injuries. Twenty of the 33 (61%) patients with multiple injuries had local co-injuries such as fractures of the upper ankle joint, tarsus and front-foot. In 83 of the 92 calcaneal fractures, the soft tissue injury was graded as 1° or 2°; in 9 fractures, the soft tissue injury was graded as 3°. In eight cases, including three patients with multiple injuries, surgery was performed immediately on the day of the trauma. Length of surgery averaged 61 min (range 20–175 min) and screening time averaged 115 s (range 20–454 s). To obtain proper retention of the fracture, between 4 and 7 Kirschner wires were used. The Kirschner wires were removed with or without local anaesthesia at an average of 10 weeks (range 7–15 weeks) as an outpatient procedure. Full weight bearing was achieved at an average of 15 weeks postoperative. Sanders classification 1 1 Table 1 Patients with immediate postoperative reconstruction of the posterior facet by Sanders fracture classification N Radiological reconstruction of posterior facet achieved Type II 15 (16.3%) 13 (86.7%) Type III 52 (56.5%) 47 (90.4%) Type IV 25 (27.2%) 16 (64.0%) The Zwipp score of 67 patients at the last follow-up evaluation 30 2 Table 2 Clinical and radiological results at last follow-up evaluation by Sanders fracture classification Sanders fracture classification Very good or good result Arthritis in lower ankle joint Normal Böhler angle achieved Overall 67 41 (61.2%) 33 (49.3%) 47 (70.1%) Type II  6 (8.9%) 4 (66.7) 1 (16.7%) 5 (83.3%) Type III  39 (58.2%) 29 (74.4%) 12 (30.8%) 31 (79.5) Type IV  22 (32.8%) 8 (36.4%) 20 (90.9%) 11 (50.0%) Thirty-seven (55.3%) of the 67 patients had no pain while full weight bearing or could walk at least 4 h without pain at last follow-up evaluation. Nine (13.4%) patients had constant pain. Thirty-three (49.3%) patients had a range of motion in the upper ankle joint identical to that of the non-affected side. Thirty-four (50.7%) patients had a restricted range of motion of up to 15° and more than half (58.2%) of the patients had achieved more than 75% of their total range of motion in the lower ankle joint. Forty-three (64.2%) of 67 patients were able to wear normal shoes while 5 (7.4%) used shoes with an unroll aid. Nineteen (28.3%) patients had obtained orthopaedic shoes on their own at last follow-up. 2 2 Complications Of the 92 surgically treated calcaneus fractures, 76 (82.6%) healed without complications. In nine (9.8%) cases, superficial skin infections, perforations of the Kirschner wires and bone dystrophy occurred and healed without any further complications. Significant complications occurred in six (6.5%) cases: three cases had osteitis of the calcaneus, one case had dislocation of the fracture requiring revision surgery and two cases had peroneal tendon impingement. Three cases of osteitis healed through conservative therapy with oral antibiotics and the two patients with impingement of the peroneal tendon refused any operative intervention. Using our method, disturbance of wound healing with skin and soft tissue necrosis requiring operative intervention was not observed. Additionally, no lower leg amputations and no total or partial calcanectomies had to be performed. Statistical analysis p  p p p p p Discussion 7 10 12 14 16 19 21 22 7 14 16 21 12 13 19 22 14 27 28 11 17 20 30 15 2 2 18 2 23 23 5 23 6 23 2 17 23 2 20 7 16 21 2 5 8 9 15 17 9 1 15 9 17 17 21 23 In our study, there was a slight reduction in the height and length of the operated calcaneus when compared to the non-operated side. With our closed reduction and internal fixation technique, more than half of the cases had a widening of the calcaneus of more than 10% when compared to the opposite side, which is an unsatisfactory result. At the same time only two patients had an impingement of the peroneal tendon that the patients considered tolerable. In summary, we presented a minimally invasive technique for the treatment of intraarticular, dislocated calcaneus fractures and were able to produce results comparable to open techniques with a lower rate of serious complications. In the majority of cases, an almost identical Böhler angle and geometry of the calcaneus was achieved when compared to the opposite side at the time of last follow-up. Simple removal of the Kirschner wires and shorter surgery time decrease patient stress and must be recognized as an advantage of this minimally invasive technique. Thus, we feel that our minimally invasive technique is a viable alternative for the treatment of intraarticular, dislocated calcaneal fractures.