Prosthetic Resurfacing Definition humeral head arthroplasty with a non-stemmed, metal prosthesis may or may not be mated with glenoid prosthesis or biologic resurfacing Advantages over conventional stemmed prosthesis no osteotomy is needed no change in anatomic offset or version improved restoration of normal biomechanics minimal bone resection shorter operative time low prevalence of humeral periprosthetic fracture easy revision to conventional arthroplasty if needed Indications cases in which the humerus anatomy is abnormal, causing: difficulty with dislocation difficulty with stem insertion examples humeral dysplasia developmental secondary Apert's disease epiphyseal dysplasias chronic Erb's palsy prior humerus fracture proximal, metaphyseal, or diaphyseal malunion hardware in place which blocks stem implantation Outcomes has demonstrated success in pain relief does not reliably improve motion at one year, considered inferior to outcomes of traditional stemmed prostheses Complications implant loosening is most common Biologic Resurfacing Also known as interpositonal allografting Concept of putting soft tissue in glenoid to reduce symptoms and obviate need for TSA Frequently combined with hemiarthroplasty of the humerus or humeral prosthetic resurfacing Indications young patients rotator cuff arthropathy GH narrowing following hemiarthroplasty GH arthritis following arthroscopic stabilization procedures Interpositional allografts include fascia lata meniscal allograft achilles allograft acellular dermal matrix Outcomes short-term outcomes (2-year) improvement: VAS pain score ASES score questionable improvement: active forward elevation active external rotation active internal rotation long-term outcomes the rate of failure by 36-months has been reported at 44% Complications difficulty converting to TSA due to scarring within the glenohumeral joint