Periprosthetic Fractures of Shoulder & Elbow Arthroplasty

For the shoulder, multiple classification systems exist (Wright & Cofield, Campbell, Worland, Groh); the Wright & Cofield system has the best intra- and interobserver reliability, but agreement across all systems - and on the preferred treatment - is only MODERATE, so the classification guides, but does not replace, individualised assessment of stem fixation and bone quality.

• Shoulder (humerus): a Type C (distal, well below a well-fixed stem) is usually ORIF like a humeral shaft fracture; a fracture around a loose stem needs revision with a long stem; strut allograft (e.g. via a posterior approach with a plate) is valuable in osteoporotic bone and for Worland B/C-type patterns. Protect the radial nerve.
• Elbow: Type II fractures hinge on stem fixation - a well-fixed stem allows ORIF, a loose stem needs component revision; the thin ulna and condylar bone loss make fixation difficult, and strut allograft / revision implants are often required.
• Always treat within overall patient optimisation (the typical patient is elderly with osteoporosis and comorbidities) and exclude infection.

The humeral-stem classifications describe only one half of the shoulder. The scapular side has its own important periprosthetic fractures, especially after reverse total shoulder arthroplasty:

• Acromial and scapular-spine stress/insufficiency fractures - a recognised reverse-TSA complication caused by deltoid over-tensioning/lengthening (the deltoid is the prime mover after a reverse). They present as new pain and loss of elevation weeks to months after surgery and are graded by the Levy classification (type 1 anterior acromion / middle-deltoid origin, type 2 posterior acromion to the scapular spine, type 3 the base of the scapular spine). Most are managed non-operatively (immobilisation); ORIF is reserved for displaced scapular-spine fractures and even then has high nonunion/complication rates, and outcomes are often worse after such a fracture.
• Glenoid / baseplate periprosthetic fracture - intra-operative or from a fall, threatening baseplate fixation and sometimes needing revision.
• Differentiate an acromial fracture from a congenital os acromiale (an unfused apophysis - typically bilateral with smooth corticated margins).

The deltoid-tensioning mechanism and the reverse design are developed in Reverse Total Shoulder Arthroplasty and Rotator Cuff Arthropathy, and the unfused apophysis in Os Acromiale.

As shoulder and elbow arthroplasty become more common (especially reverse total shoulder arthroplasty and total elbow arthroplasty for fracture and arthritis in the elderly), periprosthetic fractures around these implants are an increasingly frequent and challenging complication. They usually occur in osteoporotic bone with limited bone stock, often intra-operatively or from a low-energy fall. The key to management - exactly as at the hip - is to characterise the fracture location, the implant stability, and the bone quality.