[Locking plate osteosynthesis for fractures of the proximal humerus].

Background: Beside non-operative treatment the therapeutic options for proximal fractures of the humerus range from closed reduction and transcutaneous K-wiring to total joint replacement. While the first is regarded as minimally invasive the latter is a rather complex intervention. Plating has been disregarded as combining the disadvantages of an extended approach with too often insufficient primary postoperative stability. The new concept of completely angle stabile plate fixation aims on improving this balance by achieving greater stability even in osteoporotic fractures.

Study Design: This retrospective analysis compares 51 patients treated with a partially (39) or complete (12) angle stabile humeral plate (Königseeplatte in two modifications) with 32 patients treated according to surgeons preference with conventional plates or K-wires. Both groups were treated at the same department during the same period and did not differ in their age nor sex distribution.

Results: Until discharge there were 2 secondary dislocations discovered in group 1 and 7 in group 2. The follow-up rate was 47.1 % (24/51) in group 1 and 46.8 % (15/32) in group 2. The time interval from surgery amounted to 1.2 (0.66-1.75) and 1.0 (0.72-1.32) years respectively. Among the patients available for follow-up in group 1 8 had sustained a two-, 8 a three- and 3 a four-part fracture according to Neer's classification. In group two there were accordingly 2 two-, 8 three- and 1 four part fractures. Clinical assessment using Neer's score revealed an average of 71,8 (63.9-79.8) points in group 1 and 67.6 (47.3-78.7) in group 2. When the results of Neer's scores were expressed in percentage of the unaffected arm a mean of 73.6 (65.6-81.8) in group 1 and 69.3 (51.8-86.9) was obtained. The only statistically significant difference was observed within the sub-group of three-part fractures: treated by angle stabile plates (group 1) these patients (n = 8) achieved a mean Neer-Score of 81 (77-86) compared to 68 (52-84) (n = 8). In group 1 70.8 % of patients followed-up presented an "excellent" or "good" result according to Neer's criteria, in group 2 60 % did so.

Conclusion: We conclude from our first experience with angle stabile plates for fractures of the proximal humerus that particularly in three part fractures this method might improve functional outcome and is worth further consideration and testing.