Periprosthetic fractures after shoulder arthroplasty can be successfully treated nonoperatively

Issue: December 2010

Evan L. Flatow

Periprosthetic fractures following total shoulder arthroplasty can be extremely challenging and each one can be somewhat unique, according to Evan L. Flatow, MD, Lasker professor and chair of orthopedics at the Mount Sinai School of Medicine in New York City. “Fortunately, many of these fractures will heal without surgery.”

Hearkening back to the Neer shoulder prosthesis, “which was essentially an intermedullary rod with a small plate on the top, but lacked much shape, the fracture rate was about 1%,” according to an analysis by Robert H. Cofield that comprised of about 1,000 cases, Flatow said. “However, this fracture rate may have actually increased with the press-fit prosthetic system,” he said, noting that Tom R. Norris and Joseph P. Iannotti reported a 5% rate of intraoperative fractures with total shoulder arthroplasty (TSA).

Better prevented than treated

“Certainly, intraoperative fractures are better prevented than treated,” Flatow told Orthopedics Today. “It is important to perform careful soft-tissue releases and to avoid forceful external rotation when presenting the humeral head anteriorly during arthroplasty. This will reduce the risk of fracturing the humerus. You want to ensure that you are not torquing the shaft in these older, more osteoporotic patients who often have interlocking osteophytes. Obviously, over-reaming and broaching aggressively can be a very significant risk.”

The risk factors for periprosthetic fractures include revision arthroplasty, joint contracture, osteoporosis, female gender, uncemented stem and rheumatoid arthritis. “I believe a female patient is probably not an independent risk factor, but probably related to osteoporosis,” Flatow said.

Thomas W. Wright and Cofield have classified these fractures into three groups: type A (near the stem tip, extending proximally), type B (near the stem tip, extending distally) and type C (distal to the stem tip).

Assessing the fracture

An intraoperative fracture should be addressed at the time of surgery; for instance, by the placement of a long stem. Supplemental rigid fixation cables and struts can also be used for secured fixation to allow early shoulder range of motion (ROM).

Managing a postoperative perioperative prosthetic fracture is dependent on the fracture location and pattern. “Is the stem well fixed or loose? Were the components doing well before the fracture?” Flatow said at the 2010 Current Concepts in Joint Replacement Spring Meeting (CCJR) in Las Vegas. “If you already have a loose component or a stiff joint, it makes it more challenging than if you have a perfectly good shoulder that now has a fracture.”

For patients with a well-fixed stem and acceptable alignment, these fractures can heal nonoperatively. “With very good blood supply, even though the cortices are thin, there is a high rate of union. But this fact is often forgotten,” Flatow said.

Operative treatment may be indicated when there is a loose stem, a displaced or unacceptable angulation, or a nonunion. Among the operative options are to use an extensile Henry approach or an anterolateral approach.

“The key is to make a generous approach, if needed, so you can find nerves and isolate the shafts for fixation,” Flatow said.

Internal fixation

Internal fixation may be achieved with a plate and unicortical screws, or trying to avoid the stem with cables or strut grafts. “Take care to avoid the radial nerve during the usual approach for internal fixation,” Flatow said. Revising to a longer stem, extending two to three cortical diameters beyond the fracture, with struts or bone graft, plates and cables is also an option.

A study by Athwal and colleagues of 45 intraoperative prosthetic fractures, which included difficult-to-treat glenoid fractures, during shoulder arthroplasty found that about one-third of these fractures healed with nonoperative treatment.

Another study by Kumar and colleagues of postoperative periprosthetic fractures from shoulder arthroplasty reported that six of 19 patients healed on average 180 days with nonoperative therapy.

A third study by Campbell and colleagues of 16 intraoperative fractures treated surgically with long-stem intermedullary fixation and cerclage wiring found superior results compared to leaving the stem and adding fixation distally. – by Bob Kronemyer

References

Athwal GS, Sperling JW, Rispoli DM, et al. Periprosthetic humeral fractures during shoulder arthroplasty. J Bone Joint Surg (Am). 91(3): 594-603, 2009.

Campbell JT, Moore RS, Iannotti JP, et al. Periprosthetic humeral fractures: mechanisms of fracture and treatment options. J Shoulder Elbow Surg. 7(4): 406-13, 1998.

Flatow EL. Periprosthetic fx’s: you’re breakin’ my heart. Paper 16. Presented at the 2010 Annual Current Concepts in Joint Replacement Spring Meeting. May 23-26. Las Vegas.

Kumar S; Sperling, JW, Haidukewych G H, et al. Periprosthetic humeral fractures after shoulder arthroplasty. J Bone Joint Surg (Am). 86(4): 680-9, 2004.

Evan L. Flatow, MD, can be reached at 5 East 98th St., 9th Floor, New York, NY 10029; 212- 241-8892; e-mail: evan.flatow@msnyuhealth.org. He is a consultant for Zimmer Inc. and receives royalties from Zimmer Inc. and Innomed Inc.

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