Shoulder Hemiarthroplasty - Deltopectoral Approach

Indication. Shoulder hemiarthroplasty resurfaces the humeral side of the joint only, leaving the glenoid unresurfaced. It is chosen when the humeral head is irreparable but the glenoid either cannot or should not receive a component: - Trauma - an acute 3- or 4-part proximal humerus fracture in the elderly (older than 65-70 years) with a head-split pattern, severe comminution or a high AVN risk that makes ORIF unreliable; or a failed ORIF with humeral head collapse or AVN, articular incongruity, or a symptomatic malunion or nonunion. Note the modern trend toward reverse TSA for most elderly fracture cases.

• Elective - primary glenohumeral osteoarthritis with an intact rotator cuff but glenoid bone loss too severe for an anatomic glenoid component (or a patient who wishes to avoid one); avascular necrosis of the humeral head (Ficat stage 3-4) with a preserved glenoid; and selected rheumatoid arthritis with an intact cuff and severe humeral head destruction. Contraindications. Absolute: active infection (shoulder or systemic), neurologic dysfunction (axillary nerve palsy, complete brachial plexopathy), insufficient bone stock for component fixation, and medical comorbidities precluding surgery. Relative: rotator cuff deficiency (use reverse TSA), a young high-demand patient (anatomic or reverse TSA may be better long term), severe glenoid wear (which will progress), and likely non-compliance with rehabilitation. The one decision that matters - hemi versus reverse for fracture. Whatever the indication, the technique below is unchanged. The fracture decision is whether a hemi or a reverse is the better operation for an elderly 3- or 4-part fracture:

Pre-operative imaging and templating. Standard radiographs are a true AP (Grashey), a scapular Y and an axillary lateral. A CT is essential for fractures - to assess head-split, comminution, tuberosity displacement and glenoid involvement - and for elective cases to assess glenoid version and bone stock. MRI is added if AVN is suspected or to assess cuff integrity. Template the native humeral head (typically 42-50 mm), the canal diameter and the stem size, and note any varus or valgus deformity; avoid over-sizing in osteoporotic bone. Consent specifically for instability or dislocation, stiffness, tuberosity failure in trauma, axillary nerve injury, infection (1-2%), and the long-term glenoid erosion that drives revision (up to 50% by 5-10 years; revision rate 10-15% at 10 years, usually conversion to a reverse total shoulder). Setup. Beach-chair position with 70-80 degrees of head elevation, the entire shoulder, chest wall and arm to hand exposed, and the arm free-draped so it can be extended and rotated. General anaesthesia with an interscalene block, and IV cefazolin (or vancomycin if MRSA risk) within 60 minutes.

The goal is to expose the glenohumeral joint through the deltopectoral approach, remove the destroyed humeral head while protecting the five danger structures, restore height, version and soft-tissue balance, and - in trauma - reconstitute the tuberosities anatomically around the stem. The exposure is the heart of the operation and is laid out in full as the first steps below.

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Rehabilitation | Phase | Timing | Immobilisation | Therapy | |-------|--------|----------------|---------| | 1 - Protection | 0-6 weeks | Sling in internal rotation (tuberosity healing needs 6-12 weeks in trauma) | Pendulums from day 1; PASSIVE ROM only (forward elevation to 90 degrees then 120 degrees, external rotation 20-30 degrees); no active shoulder motion | | 2 - Early active | 6-12 weeks | Removable sling (once subscapularis healed and tuberosities uniting) | Active-assisted ROM (6-8 weeks), active ROM (8-12 weeks), isometric strengthening (10-12 weeks) | | 3 - Strengthening | 12-24 weeks | None for light tasks | Progressive resistive exercises (Theraband, light weights); rotator-cuff and scapular-stabiliser work | | 4 - Return to function | 6-12 months | None | Unrestricted ADLs and low-demand recreation; permanent restriction on heavy labour and high-impact sport | Expected outcomes. Pain relief is excellent (80-90% good or excellent). ROM depends on the indication: trauma cases achieve roughly 90-120 degrees of forward elevation and 20-40 degrees of external rotation (governed by tuberosity healing), while elective cases reach 120-150 degrees of elevation and 40-60 degrees of external rotation when the cuff is intact. Strength is generally weaker than after anatomic or reverse TSA, especially in trauma. Implant survival is 85-90% at 10 years, with a 10-15% revision rate at 10 years - higher in trauma (tuberosity failure, conversion to reverse) and driven in elective cases by glenoid erosion. Complications

The five critical danger structures

Epidemiology. Proximal humerus fractures are among the most common osteoporotic fragility fractures, typically sustained as a low-energy fall in the elderly, and they are the basis for most fracture hemiarthroplasties. For elective glenohumeral osteoarthritis, hemiarthroplasty has been progressively displaced by anatomic and reverse total shoulder arthroplasty and is now reserved for the specific situations where a glenoid component is not feasible - inadequate glenoid bone stock, or a very young patient in whom glenoid loosening is a concern. Why hemiarthroplasty fails long term. Hemiarthroplasty resurfaces only the humerus, leaving the glenoid cartilage to articulate against a metal or ceramic head. Because the prosthetic head is far harder than native glenoid cartilage, eccentric and imbalanced loading progressively erodes the glenoid - the central long-term problem, evident radiographically in up to 50% of patients by 5-10 years. In trauma the separate problem is biological: the outcome hinges not on the implant but on whether the reattached tuberosities heal, which is unreliable in elderly osteoporotic bone.

Key evidence. Boileau's multicentre series of fracture-sequelae arthroplasties (2001) showed that greater-tuberosity osteotomy was the single factor most strongly associated with a poor outcome - establishing the central principle that anatomic tuberosity healing, not the implant, governs function. The same group's later fracture-stem study (Boileau, 2013) found anatomic tuberosity healing in 87% with a fracture-specific stem versus 45% with a conventional stem, with age 75 or older, female sex and a bulky stem predicting failure - a key argument for reverse arthroplasty in elderly women. Namdari's systematic review (2013) showed reverse arthroplasty gave function independent of tuberosity healing but at roughly four times the odds of a complication. For elective OA, Rispoli's 11-year follow-up (2006) documented progressive glenoid erosion driving a high revision rate, and the Nordic registry study (Rasmussen, 2018) confirmed lower survivorship for hemiarthroplasty than anatomic TSA (93% versus 96% at 10 years). Together this evidence explains why hemiarthroplasty has been displaced by anatomic TSA for elective OA and by reverse TSA for elderly fractures.