This study evaluated the effect on movement under load of three different techniques for re-attachment of the tuberosities of the humerus using test sawbones. In the first, the tuberosities were attached both to the shaft and to each other, with one cerclage suture through the anterior hole in the prosthesis. The second technique was identical except for omission of the cerclage suture and in the third the tuberosities were attached to the prosthesis and to the shaft. An orthogonal photogrammetric system allowed all segments to be tracked in a 3D axis system. The humeri were incrementally-loaded in abduction, and the 3D linear and angular movements of all segments were calculated. Displacement between the tuberosities and the shaft was measured.

The first and second techniques were the most stable constructs, with the third allowing greater separation of fragments and angular movement. Separation at the midpoint of the tuberosities was significantly greater using the latter technique (p < 0.05). The cerclage suture added no further stability to the fixation.

This study compared the effect of a computer-assisted and a traditional surgical technique on the kinematics of the glenohumeral joint during passive abduction after hemiarthroplasty of the shoulder for the treatment of fractures. We used seven pairs of fresh-frozen cadaver shoulders to create simulated four-part fractures of the proximal humerus, which were then reconstructed with hemiarthroplasty and reattachment of the tuberosities. The specimens were randomised, so that one from each pair was repaired using the computer-assisted technique, whereas a traditional hemiarthroplasty without navigation was performed in the contralateral shoulder. Kinematic data were obtained using an electromagnetic tracking device. The traditional technique resulted in posterior and inferior translation of the humeral head. No statistical differences were observed before or after computer-assisted surgery. Although it requires further improvement, the computer-assisted approach appears to allow glenohumeral kinematics to more closely replicate those of the native joint, potentially improving the function of the shoulder and extending the longevity of the prosthesis

Background. Functional outcomes of conservatively managed, valgus impacted proximal humeral fractures are poor. Operative fixation can improve results but can be technically challenging. We prospectively assessed outcomes following fixation of valgus unstable proximal humeral fractures with a novel hybrid fixed angle blade plate, at a minimum of 12 months follow up. Methods. A new hybrid fixed angle blade plate design (Fx Plate, Exactech, Gainesville, USA) was used by the senior author to treat patients with displaced and potentially valgus unstable proximal humeral fractures, at our institution between November 2012 and March 2014. The study was approved by the research and development department. Outcomes were prospectively assessed using the Oxford and Constant shoulder scores and quality of life was assessed using the SF-36 questionnaire. Radiographs were taken at regular intervals to assess fracture healing. Results. In total 12 patients were identified and included in the study. All patients had comminution of the medial calcar, with potentially valgus unstable fracture patterns. Six of the patients had two-part displaced fractures, whereas six had three and four-part fractures. One patient died for reasons unrelated to surgery and three others were lost to follow up. Average follow up after surgery was 15.4 months (Range 12–20 months). At final follow up the average Oxford Shoulder Score was 41 (35 to 48) and Constant Score 73 (60 to 87), indicating a good functional outcome of the operated side. The average physical and mental component scores of the SF-36 questionnaire were 49 and 52 respectively, suggesting a good overall quality of life. Radiographs, taken at final follow up, confirmed fracture union in all cases. No significant complications occurred following surgery. Conclusions. Patients with displaced, potentially valgus unstable, proximal humeral fractures remain a challenging cohort to treat. Our results, however, indicate good functional and radiographic outcomes when using a novel hybrid fixed angle blade plate