To the Editor:

We appreciate Mr. Norris’ very relevant comments. Periprosthetic fractures after shoulder arthroplasty, even with stemmed implants, are very uncommon, being 0.46 percent in our patient group. However, as other complications decrease, such as symptomatic glenoid loosening, periprosthetic fracture is becoming a more prevalent complication. Importantly, however, the article was written to illustrate some of the difficulties in obtaining healing of these fractures, although healing almost always eventually occurs.

Our article did not address intraoperative fractures, and these are even less common. We believe intraoperative fractures can be avoided by careful preoperative planning including preoperative templating; adequate exposure of the shoulder with complete soft tissue releases in the bursa and of the shoulder capsule to avoid torsional forces on the humerus; correct alignment of the instrumentation during bone preparation, including the use of intraoperative x-rays where this may be in doubt, such as in old fractures with some degree of malunion; and use of implant systems that offer a suitable number of prosthetic sizes so that one can obtain an optimal humeral fit. It is also well recognized that if a cortical defect in the humerus exists for some reason, the stem should bypass the defect by four to five centimeters.

Mr. Norris mentions that he prefers surface replacement humeral arthroplasty,and this is a very reasonable treatment option. We have traditionally preferred to use a stem and continue to prefer that approach as we feel we can obtain better soft tissue releases, better prepare and fix the glenoid component, and achieve both proximal and distal fixation of the humeral component. Of course, when arthroplasty is chosen to treat comminuted fractures of the proximal humerus, stems are necessary.

We agree that use of a stem can create some of the problems which lead to later fracture. In addition to a large number of these patients having pre-existing osteopenia in this series, three of the arthroplasties had complete radiolucent lines around the stem, and three had a shift in component position, all indicative of component loosening. In two, there was substantial osteolysis, and in one, reaming at surgery was slightly more then typical. So even though uncommon, the use of a stemmed component can create a situation that might engender a fracture subsequent to an injury.

Mr.Norris mentions the ease of revision surgery with surface components. We would recommend that for those fractures with slight displacement and a well fixed humeral component, nonoperative treatment is sufficient, at least initially. For fractures with a well fixed component and substantial displacement, we recommend open reduction and internal fixation. Revision surgery is usually reserved for patients with a loose humeral component.

These fractures can be very slow to heal: nonoperative treatment requires about six months and operative treatment about nine to twelve months to observe bone union. Thus, these are difficult fractures, and it is a very good idea to do a variety of things to avoid them when at all possible. Mr. Norris suggests one of the options to do so.

To the Editor

We read with interest the article “Periprosthetic Humeral Fractures After Shoulder Arthroplasty” (2004;86:680-9), by Kumar et al.

The authors state that periprosthetic fractures following shoulder arthroplasty are relatively uncommon. However, they also state that the prevalence of this complication is 2.4%[1] and that peri-prosthetic fracture may account for 20%[2] of all complications associated with total shoulder arthroplasty. Most of these injuries involve the humeral shaft and occur at the time of the operation[3].

We use the Cementless Surface Replacement Arthroplasty CSRA (Copeland prosthesis). This prosthesis has published results equivalent to stemmed humeral implants[4,5]. The CSRA does not involve reaming or insertion of a stem into the humeral shaft thereby reducing risk of periprosthetic fracture. Only one case of periprosthetic fracture is noted in Levy and Copeland’s series[4]. This was easily revised using a stemmed prosthesis.

We therefore feel that the results of CRSA are equivalent to those of a stemmed prosthesis and are associated with a reduced risk of periprosthetic fracture. If such a fracture does occur, it is easier to revise due to the preservation of bone stock.

References

1. Worland RL, Kim DY, Arredondo J. Periprosthetic humeral fractures: management and classification. J Shoulder Elbow Surg. 1999;8:590-4.

2. Wirth MA. Periprosthetic fractures in the upper extremity. In: Rockwood D, Green DP, Bucholz RW, Heckman JD, eds. Fractures in adults. Philadelphia: J.B. Lippincott, 1996;1:540-576.

3. Wirth MA, Rockwood CA. Current concepts review: complications of total shoulder replacement arthroplasty. J Bone Joint Surg [Am] 1996;78- A:603-16.

4. Levy O, Copeland SA. Cementless surface replacement arthroplasty of the shoulder. 5-to 10-year results with the Copland Mark-2 prosthesis. J Bone Joint Surg [Br] 2001;83-B:213-21.

5. Levy O, Copeland SA. Cementless surface replacement arthroplasty (Copeland CRSA) for osteoarthritis of the shoulder. J Shoulder Elbow Surg 1993;13:268-71.