Introduction: In most of the reported series, scapular notching in inverse shoulder arthroplasty has been identified as a major problem. Therefore, a novel concept has been developed in order to minimize the incidence and the evolution (pathophysiology) of scapular notching. The current cohort study is now large enough to examine the results with special attention on notching.

Methods: A dual peg design of the metaglene with CaP coating provides high primary and secondary stability. “Geometrical” notching is reduced by inferior (eccentric) fixation of the glenosphere on the metaglene, beveling of the medial part of the humeral inlay, and by the choice of three different sizes of the glenosphere (36, 39 and 42). “Biological” notching is addressed by inversion of the components: the epiphysis – as the mobile part – is metallic. Its contact to the scapula, should this occur, cannot lead to polyethylene wear. This study is a prospective multicentric study on Affinis Inverse and Affinis Fracture Inverse shoulder prosthesis (Mathys Ltd Bettlach, Switzerland), which is running in 7 European hospitals since December 2007. All cases but two (lost to follow-up) are included.

Preoperative and all postoperative radiographs were reviewed. Notching has been graded 0 to 4, on a scale adapted after Sirveaux.

Results: At submission deadline for the abstract, 163 cases were included. Grade 1 notching was detected in 8 cases (4.9%), and grade 2 notching in one. In those cases, notching developed early, but was not progressive over time. There were no cases of grade 3 or 4. In 17 cases, the X-rays were not assessable and therefore it was impossible to definitively rule out a possible grade 1 notching. None of the Affinis Fracture Inverse prostheses produced any notching. New bone apposition on the inferior aspect of the scapula was detected in 15 cases. We postulate this to be a metaplasia of the long head of the triceps due to local periosteal stimulation.

Conclusions: The present design leads to a very low rate of scapular notching. Even in the 9 cases where notching was present, it appears that the epiphysis only created the space it needed, without any ongoing osteolytic process beyond this. Specific prosthetic design improves both quantity and quality of scapular notching.

OBJECTIVES: In recent years the incidence of proximal humerus fractures increased strongly. The optimal treatment of displaced, unstable fractures is still controversial. One of the major problem seen in previous treatment options was implant failure with secondary dislocation, pseudarthrosis and AVN. New angular stable implants promise a stronger anchorage and allow early functional aftertreatment, especially in osteopenic bone. Aim of this prospective case-series was to assess complication risks and functional outcome after ORIF with an angular stable form plate

DESIGN: Prospective case-series

SETTING: Multicenter study in 8 European Trauma Units

PATIENTS: 157 patients were treated for 158 displaced proximal humerus fractures

INTERVENTION: ORIF with a PHILOS^™ plate.

RESULTS: According to the AO/ASIF classification 25%, 61% and 37% were classified as type A, B and C, respectively. One year follow-up rate was 84%, whereupon 6 patients had died in the mean time and 18 were lost to follow-up. Overall 71 complications were observed in 53 patients and led to 39 unplanned re-operations, whereupon most frequent were primary screw perforations (n=22), secondary screw perforations (n=13)–mostly with secondary impaction (n=11), and AVN (n=8). Increasing age and severity of fractures influenced the occurrence of complications, since the risk to obtain a complication was doubled in patients over 60 years compared to younger (Relative Risk 1.9; Fischer’s Exact, p=0.022) as well as in AO/ASIF B- and C-fractures compared to A-fractures (Relative Risk=1.8; Fischer’s Exact, p=0.05). Risks for complications related to the implant, surgical technique or fracture and bone were 9%, 20% and 13%, respectively. Within one year all fractures healed and 5 secondary dislocations were observed. The mean (SD) Constant score of the injured shoulder improved during follow-up period to 72 points (15.2) at 12 months follow-up, when 87% (16.6%) of the contralateral shoulder was reached. Across all follow-up examinations the Constant score in relation to the contralateral shoulder impaired with increasing severity of the fracture (ANOVA, p=0.006). The mean (SD) DASH score after one year was with 16 points (21.1) worser (T-test, p< 0.001) than before the accident [5.2 (11.4)].

CONCLUSIONS: Fixation with a Philos plate provides high stability to preserve achieved reduction, which benefits the good functional outcome. However surgical technique related complication risks are high, particularly due to screw perforations into the joint. Augmented awareness and improvement of surgical technique should reduce these risks. Complex fracture types and higher age increases the risk to sustain complications, where as only severity of fractures impairs the functional outcome.