Reverse Shoulder Arthroplasty (RSA) has been widely accepted for the treatment of rotator cuff arthropathy. There are a number of other shoulder pathologies where the reverse shoulder prosthesis can salvage previously untreatable shoulder conditions and restore function to the shoulder. This is a series of cases where RSA has been used to treat shoulder fractures. Our indications for the reverse prosthesis in fracture management were: Revision of failed fracture fixation with a deficient rotator cuff – 2 patients; Acute 3 and 4 part fractures in the elderly, osteoporotic – 1 patient; Acute 4 part fracture dislocation in elderly, osteoporotic – 1 patient; Revision of non-union and malunions – 5 patients; Revision of hemiarthroplasties which were initially done for fracture management – 5 patients. There were a total of 14 cases treated for fractures out of 123 reverse shoulder arthroplasties performed. The average age for the fracture cases was 68 years (range 47–87) and for non-fracture RSA cases 73 years (range 51–88). The average follow-up Constant Score was 53 for fracture cases and 67 for non-fracture RSA cases. Complications included 1 dislocation and 1 deep infection. The problem with treatment of complex cases is there is an increased risk of complications. Problems encountered in the use of reverse shoulder arthroplasty in complex diagnoses include: instability, notching of scapula, scapula fractures, sepsis, lack of bone stock, poor quality soft-tissue and deficient deltoid muscle due to numerous previous surgical procedures, distortion of anatomy due to trauma, subscapularis deficiency and problems encountered from metal implants in situ.Material.
Results.
Crosby and Colleagues described 24 scapula fractures in 400 reverse shoulder arthroplasties and classified scapula fractures after reverse shoulder arthroplasty into 3 types. Type 1 – true avulsion fracture of acromion related to a thinned out acromion (post-acromioplaty or cuff arthropathy). A small bone fragment dislodges during reduction of RSA. Type 2 – Acromial fracture due to Acromio-clavicular (AC) joint arthrosis. They feel the lack of movement at the AC joint leads to stresses across the acromion and cause it to fracture. They recommend AC joint resection and ORIF of acromion, if the acromion is unstable. Type 3 – true scapula spine fracture caused by the superior screw acting as a stress riser. This fracture occurs about 8 months after the arthroplasty and is a true stress fracture requiring open reduction and internal fixation. Of 123 reverse shoulder arthroplasties performed from Jan 2003 to Feb 2011, a total of 6 scapula fractures were encountered post-surgery. Three were acromial fractures and three were scapula spine fractures all related to trauma. The fractures of the spine occurred between 6 months and 4 years post arthroplasty. We feel the fractures were traumatic but did occur through the posterior or superior screws from the metaglen. where stress risers developed for a fracture to occur. We found that using a sliding osteotomy of the spine of the scapula to bridge the defect of the scapula and a double-plating technique using two plates at 90 degrees to each other provides a satisfactory outcome after 3–6 months where patients can start actively elevating again. This method of treatment will be presented.
