summary A shoulder hemiarthroplasty is a procedure in which the humeral articular surface is replaced with stemmed humeral component. The most common indication is glenohumeral arthritis when the glenoid bone stock is inadequate for a total shoulder arthroplasty. It is contraindicated in patients with coracoacromial ligament deficiency. Indications Indications primary arthritis, if: rotator cuff is deficient glenoid bone stock is inadequate risk of glenoid loosening is high young patients active laborers rotator cuff arthropathy hemiarthroplasty > rTSA if able to achieve forward flexion > 90 degrees osteonecrosis without glenoid involvement proximal humerus fractures three-part fractures with poor bone quality four-part fractures head-splitting fractures fracture with significant destruction of the articular surface Contraindications infection neuropathic joint unmotivated patient coracoacromial ligament deficiency provides a barrier to humeral head proximal migration in the case of a rotator cuff tear superior escape will occur if coracoacromial ligament and rotator cuff are deficient Outcomes Rotator cuff deficiency status of the rotator cuff is the most influential factor affecting postoperative function in shoulder hemiarthroplasty Proximal humerus fractures provides excellent pain relief in a majority of patients outcome scores inversely proportional to patient age time from injury to operation Preoperative Imaging Radiographs true (Grashey) AP of shoulder taken 30-40 degrees oblique to the coronal plane of the body findings helps determine extent of DJD delineation of fracture pattern axillary view findings look for posterior wear of glenoid helps quantify displacement in cases of fracture CT scan obtain CT scan to determine glenoid version and glenoid bone stock useful if fracture pattern is poorly understood after radiographic evaluation MRI useful for evaluation of rotator cuff techniques Approach deltopectoral approach Shaft preparation and prosthesis placement humeral head resection start osteotomy at medial insertion line of supraspinatus determine retroversion, implant height and head size retroversion 30° of retroversion is ideal lateral fin should be slightly posterior to biceps groove excessive anteversion leads to risk of anterior dislocation excessive retroversion leads to risk of posterior dislocation implant height greater tuberosity should be 7 to 8 mm below the top of the prosthetic humeral head functions to maintain cuff and biceps tension recreate normal contour of medial calcar technique to achieve cement prosthesis proud distance from top of prosthesis head to upper border of pectoralis major should be 56mm. head size determine size by using radiograph of contralateral shoulder or measuring size of native head removed earlier in procedure using too large of a head may "overstuff" joint Fixation cemented prosthesis standard of care provides better quality of life, range of motion, and strength compared to uncemented humeral component Tuberosity reduction introduction tuberosity migration is one of the most common causes of failure for fractures treated with hemiarthroplasty technique strict attention to securing the tuberosities to each other and to the shaft autogenous bone grafting from the excised humeral head will decrease the incidence of pull-off and improve healing rates tuberosity reduction must be anatomic or it may lead to a deficit in rotation The "Ream and Run" Procedure introduction shoulder hemiarthroplasty with concentric glenoid reaming (non-prosthetic glenoid arthroplasty) avoids the potential limitations associated with a prosthetic glenoid component provides patient with the opportunity for a level of activity beyond that recommended for a total shoulder arthroplasty technique spherical reaming of the osseous glenoid surface to optimize both glenohumeral stability and the distribution of load applied by the humeral prosthesis the glenoid face is reamed to a single smooth concavity using a nubbed spherical reamer outcomes excellent functional and radiographic 2-year outcomes Rehab Early passive motion until fracture has healed duration usually 6-8 weeks Strengthening exercises begin once tuberosity has fully healed Complications Progressive glenoid arthrosis increased risk with young patients active patient treatment conversion to total shoulder arthroplasty Tuberosity displacement/malunion one of the most common complications of shoulder hemiarthroplasty when used to treat fracture treatment repositioning of the tuberosity with bone grafting Joint overstuffing may lead to stiffness accelerated arthritis of glenoid Subcutaneous (anterosuperior) escape occurs when both rotator cuff and coracoacromial arch are deficient better outcomes with conversion to reverse shoulder arthroplasty compared to anatomic TSA