Periprosthetic Fractures of Shoulder & Elbow Arthroplasty

Shoulder: Wright and Cofield. A periprosthetic humeral fracture after anatomic or reverse arthroplasty is described by where it lies relative to the tip of the humeral stem. Wright and Cofield is the most commonly used system.

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How far to trust it. Several systems exist for the shoulder: Wright and Cofield, Campbell, Worland and Groh. Wright and Cofield has the best intra- and interobserver reliability, but agreement across all of them, and on the preferred treatment, is only moderate. The classification guides, but does not replace, individual assessment of stem fixation and bone quality.

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Elbow: Mayo (O'Driscoll and Morrey). Fractures around a total elbow arthroplasty are graded by location, and those along a stem are subdivided by whether that stem is well fixed or loose.

Know the construct before the fracture. Identify the implant, anatomic or reverse at the shoulder, linked or unlinked at the elbow, then decide whether its stem is fixed. Lucency, subsidence and cement-mantle failure are the signs of loosening.

Imaging. Radiographs, with CT where needed, show the fracture pattern and its location relative to the stem tip, and they are read for bone quality and stock at the same time.

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Infection and nerves. Rule out infection before any revision. Examine the limb neurovascularly; the nerve at risk differs between the humerus and the elbow, as set out under prevention below.

Treat the patient as well as the fracture. The typical patient is elderly, with osteoporosis and comorbidities, so every plan sits within overall patient optimisation.

Well-fixed implant: treat the fracture. Keep the well-functioning implant and fix the bone around it by ORIF with a long plate, screws and cerclage, often with a strut allograft. Selected stable, undisplaced or proximal patterns can be managed non-operatively.

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Loose implant: revise it. A loose stem is revised to a longer-stemmed component that bypasses the fracture, with or without supplementary fixation or graft. Fixing the fracture alone over a loose stem will fail.

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Fixation in osteoporotic bone. The bone is frequently osteoporotic and stock is limited, especially in revision and around the elbow, so the construct is augmented with long plates, multiple points of fixation, cerclage around the stem and strut allograft. Healing rates are good with appropriate, stability-matched treatment.

At the shoulder. A Type C fracture, distal and well below a well-fixed stem, is usually fixed like a humeral shaft fracture. Strut allograft, for example with a plate through a posterior approach, is valuable in osteoporotic bone and for Worland B/C-type patterns.

The strut. Struts add cortical support and distribute load where osteoporotic bone cannot hold enough screws around the stem. A fibular strut is split longitudinally, temporarily controlled with screws, placed against the anterior and medial humerus and secured with circumferential tapes.

When fixation fails. Early loss of reduction calls for a failure analysis before anything is repeated: was the fixation too short, the bone purchase inadequate, the stem loose, or the fracture biology unsupported? Repeating the same construct is unlikely to succeed. The figures below follow a failed plate construct through revision fixation with struts.

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At the 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 or revision implants are often required.

Composite reconstruction. A humeral allograft-prosthesis composite, joined to host bone with a compression plate and a cemented revision stem, is a salvage option for loose components with segmental humeral bone loss. It is not routine treatment for a well-fixed stem.

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Many happen on the table. At the shoulder the moments of risk are:

• Humeral preparation: broaching, reaming and especially impaction of a press-fit or uncemented stem in an osteoporotic or stiff, ankylosed shoulder
• Dislocation, reduction and arm manipulation or retraction: forceful torque on a stiff arthritic or revision shoulder can spiral the humeral shaft
• Glenoid exposure and reaming
• Cement pressurisation

At the elbow, the thin ulna and the deficient distal humeral columns crack during canal preparation, broaching and component impaction.

Recognise it. A feel or sound of a crack means inspect and image intra-operatively. An unrecognised intra-operative fracture presents later as early post-operative pain, loss of fixation or loosening.

Treat it immediately. Place cerclage cables around the fracture, use a longer stem to bypass it and add strut graft as needed, then protect or modify the rehabilitation.

Prevent it. Use gentle technique, adequate soft-tissue releases and exposure before levering, and careful sequential broaching, with heightened awareness in osteoporotic, revision and stiff cases.

Osteoporotic bone is named repeatedly as the reason these fractures happen and are hard to fix, and it is then usually left there as an adjective. Three things follow from it that belong in the treatment plan rather than the description.

Treat the osteoporosis. A periprosthetic fracture is a fragility fracture. A low-energy fall that breaks a humerus around a stem is the same event as any other fragility fracture, and carries the same implication: this patient will have another. Fixing the humerus and discharging the patient treats the event and ignores the disease. The fracture should trigger a bone-health assessment, exactly as a wrist or hip fragility fracture does: falls assessment, vitamin D and calcium, DXA where it will change management, and consideration of anti-resorptive or anabolic therapy.

Know which nerve is at risk. For the humerus it is the radial nerve, at the spiral groove and along any plate applied to the shaft. For the elbow it is the ulnar nerve, which runs immediately adjacent to the medial column and is the nerve injured in elbow arthroplasty and its revision.

Why revision is different. The ulnar nerve has usually been handled or transposed at the index operation, so it may not lie where the anatomy says it should, and it is frequently encased in scar. Identify and protect it deliberately rather than assuming its position. In the posterior revision exposure for a humeral allograft-prosthesis composite, both the ulnar and the radial nerve are identified before scar release, graft preparation and plate placement. The detail of nerve management in elbow arthroplasty, along with triceps insufficiency, is in Total Elbow Arthroplasty.

The limit as prevention. The counselling given after the index arthroplasty is the main modifiable determinant of whether a periprosthetic fracture happens at all, so it is worth restating at every review rather than once at discharge.

The limit as a diagnostic clue. A periprosthetic fracture or a loose component in a patient who reports adhering to the limit should prompt a look for another explanation, infection or a fall that was itself a warning about bone quality and balance, rather than being attributed to activity by default.

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, and new pain after arthroplasty demands imaging of both the humeral and the scapular side rather than assuming the stem is the only possible source.

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Acromial and scapular-spine stress fractures. These stress or insufficiency fractures are a recognised complication of the reverse, caused by deltoid over-tensioning or lengthening; after a reverse the deltoid is the prime mover. They present with new pain and loss of elevation weeks to months after surgery, and are graded by the Levy classification:

• Type 1: the anterior acromion, at the middle-deltoid origin
• Type 2: the posterior acromion to the scapular spine
• Type 3: the base of the scapular spine

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Treatment. Most are managed non-operatively with immobilisation. ORIF is reserved for displaced scapular-spine fractures and even then has high nonunion and complication rates, and outcomes are often worse after such a fracture.

Glenoid and baseplate fractures occur intra-operatively or from a fall, threaten baseplate fixation and sometimes need revision.

Os acromiale. Distinguish an acromial fracture from an os acromiale, an unfused apophysis, which is 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.

A rising problem in fragile bone. 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 organising principle. Management follows exactly the logic of the hip and its Vancouver classification. Characterise three things before deciding anything: the fracture location, the implant stability (is the stem well fixed or loose?) and the bone quality.