[Comparison of functional outcomes in angle-stable osteosynthesis of comminuted fractures of the proximal humerus with those in percutaneous Kirschner-wire fixation. A prospective study of mid-term results].

PURPOSE OF THE STUDY To evaluate the mid-term results in a group of patients with displaced comminuted (three- and four-fragment) fractures of the proximal humerus treated by angle-stable plate osteosynthesis and compare them with the results in the patients in whom the method of percutaneous Kirschner-wire (K-wire) fixation was used. MATERIAL AND METHODS The group treated with angle-stable implants (ASI group) consisted of 55 patients, 13 men and 42 women. A Targon Ph nail was used in 32 and a Philos plate in 23 patients. These patients were compared with a group of nine patients, one man and eight women, treated by percutaneous K-wire fixation (K-wire group). At a follow-up of 12 months at least, final Constant (CS) and DASH scores were assessed. The CS was related to the values for the unaffected limb, and an individual relative CS was calculated and expressed in percent. The mean follow-up was 30 (range, 13-55) months in the ASI group and 58 (range, 39-76) months in the K-wire group. The following seven characteristics were evaluated : fracture type, surgical technique, dominance of the affected limb, patient age, injury-surgery interval, and individual relative CS and DASH scores. The results were statistically analysed with a 5% level of statistical significance set for all tests. RESULTS The average age in the ASI group was 62.1 years, with 64.7 (range, 29-95) years for women and 35.5 (range, 26-76) years for men. In the K-wire group the average age was 66.1 (range, 53-84) years. The functional outcomes in four-fragment fractures were significantly worse than in three-fragment fractures (mean relative CS and DASH scores of 56 and 21 versus 72 and 32). The K-wire group showed a significantly worse functional outcomes than the ASI group in both the mean relative CS score (p<0.001) and the mean DASH score (p=0.003). No significant relationship was found in any other pair of variables. The patient's age had no effect on functional outcome, as assessed by CS (p=0.412) and DASH (p=0.076) and the injury-surgery interval had no influence, either (CS, p=0.220; DASH, p=0.118). There was no relation between the patient's age and choice of the surgical method (p=0.467), between the patient's age and a fracture type (p=0.356) and between the patient's age and injury to either a dominant or a non-dominant limb (p=0.659). Dominance or non-dominance of the affected limb had no effect on CS or DASH scores (p=0.662 and p=0.302, respectively) or on a type of fracture (p=0.183). DISCUSSION Several surgical techniques used for the treatment of proximal humerus fractures suggest the absence of consensus in therapy. Novel angle-stable implants show better biochemical properties and meet criteria required in minimally invasive techniques. Some authors prefer intramedullary nailing for three-fragment fractures and the use of an angle-stable plate for four-fragment fractures. These indication criteria were also confirmed by the results of our study. CONCLUSIONS The analysis of functional outcomes showed that the therapeutic effect of K-wire transfixation was significantly worse than the effect of the angle-stable plate technique, and therefore the authors stopped using this method. At present intramedullary nailing is indicated in two- and three-fragment fractures and in some less displaced four-fragment fractures. An angle-stable plate is used in severely displaced four-fragment fractures. If the head is broken or dislocated, older patients are primarily indicated for hemiarthroplasty and younger ones for humeral head reconstruction.