Proximal fractures of the humerus are a frequently encountered and a hard to solve problem for the orthopaedic surgeon. Open reduction and internal fixation with anatomical plate and locking head screws are nowadays the gold standard treatment. A new plate for the repair of proximal fractures or the humerus has been designed and mechanically tested. The authors herewith present the new device and the preliminary results at one year follow up.
Material and methods
Twenty-two fractures of the proximal humerus have been treated by deltopectoral approach then reduced and fixed respecting as much as possible the blood supply to the fragments.
The plate (DiPhos H, Hit Medica, San Marino, Italy) is manufactured in CFR peek (30% carbon fibre reinforced peek).
The titanium screws are designed with a self tapping head.
The mean age of the treated patients was 64 ys (range 41-78) while the average follow-up was 9 months (range 13-6). The plate was removed in three cases after healing of the fracture one year from the implant. The scar tissue covering the plate was retrieved at the time of explant and submitted to histological examination for the detection of signs of local reaction.
Postoperative rehabilitation started on day two after surgery, with CPM machine.
At the second month follow-up visit we allowed a more aggressive rehabilitation program.
Results
All fractures healed at follow-up, the mean Constant Score was 91 (85-97) and the Dash Score was 31(27-53).
Plate removal was achieved without any problem in all cases. All screws were strongly attached to the plates’ holes, but without locking phenomena due to galvanic corrosion processes.
No tissue reaction were observed at histological exams, after plate removal.
Discussion/Conclusion
The new internal fixation device presents the following unique features. PEEK is a material that allows ideal hole tapping by the screw and optimal locking screw stability in multiple directions, according to the surgeon’s needs. The locking screws revealed extremely reliable self-tapping stabilization properties into the plate holes proving to be very useful for their polyaxial properties in every case.
The PEEK translucency at X-ray evaluations allows the surgeon to achieve a careful bone reduction during surgery (particularly on the axial view) and to follow the bone healing process in time.
No problems related to galvanic corrosion at the screws-plate interface has to be expected, in fact all implants could be removed uneventfully.
Histological examination of the tissue around the plate confirmed the optimal tolerability of the new material.
Due to these very satisfactory preliminary results a multicenter trial will soon be started to further validate this new internal fixation device.
R. Rotini, MD, E. Guerra, MD, A. Marinelli, MD G. Bettelli, MD, M. Nigrisoli, MD
Shoulder & Elbow Division Rizzoli Orthopaedic Institute Bologna (Italy)
