Abstract
Background
The procedures of total elbow and shoulder replacements increased 6% to 13% annually from 1993 to 2007 with revision-related burden increasing from 4.5% to 7%. The revisions of the shoulder and elbow prostheses due to aseptic loosening, periprosthetic fractures, infections have led to the use of standard or custom-made implants due to significant bone loss. This study reports our experience in the management of complicated primary and revisions of total shoulder and elbow replacements with significant humeral bone loss and in metabolic diseases of the elbow and shoulder treated with bone resection using The Mosaic Humeral Replacement System.
Patients and Materials
A total of 20 patients underwent total elbow or shoulder arthroplasty using the Mosaic Humeral Replacement System (Biomet, UK). The Mosaic system was used in 8 shoulder arthroplasties (Group A) and in 12 elbow arthroplasties (Group B). The underlying pathologis in Group A included 2 malunited proximal humerus fracture, 1 humeral osteomyelitis, 1 shoulder chondrosarcoma, 1 aggressive Gigantic Cell Tumor with prosthetic fracture, 2 metastatic lytic lesion, and 1 failed fixation of non-union proximal humerus. Figure 1 shows Mosaic implant after complex fracture of proximal humerus. Reasons for Mosaic arthroplasty in Group B included 3 humeral component revisions due to periprosthetic fracture, 1 prosthesis breaking-up with fractures, 1 revision of loose Souter Strathclyde prosthesis, 1 loose prosthesis due to infection, 1 highly comminuted elbow fracture, 1 aseptic loosening of humeral component of total elbow replacement, 3 revision of total elbow replacement due loosening and 1 pathological distal humerus fracture due to metastasis. Figure 2&3 shows pre- and post-operative Mosaic implant following complex periprosthetic fracture of distal humerus.
Clinical Observation/Discussion
The Mosaic Humeral Replacement System is a complete system for complex revision, salvage/oncology, and complex humeral fractures. It is a completely modular system which can be adapted to different patient anatomies and indications. It has been designed to face several surgical challenges, including reattaching soft tissues, properly tensioning the glenohumeral joint and restoring joint function. It is a cost-effective procedure with the benefits of a custom made humeral component in a standard tray. Our study shows that good results can be achieved with this form of treatment. Radiological assessment of all patients showed a satisfactory position of the implant with appropriate margin of bony resection. One patient with proximal and another one with distal humeral Mosaic replacement had late infection. One patient had aseptic loosening 3 years after distal humeral replacement. Most of the patients had satisfactory improvement in range of movement and chronic pain.
While primary clinical observations and imaging results indicate acceptable results with Mosaic arthroplasty; a realistic assessment can only be achieved in long-term using the appropriate outcome measures. At the present we continue to regularly assess the patients clinically and radiologically and by means of Liverpool elbow score for distal and Quick- DASH for proximal Mosaic Humeral Replacement System and plan to report the long-term results in due time.
