Raiss et al. studied the use of the reverse shoulder prosthesis for the treatment of proximal humeral nonunions. Their reasonably large multicenter retrospective study attempts to provide answers regarding a condition that has historically been very challenging to treat. The authors did find improved functional results, with better forward elevation, external rotation, and Constant scores, in the patients in their study. They noted improved strength and shoulder range of motion when the tuberosities were preserved and the subscapularis was repaired. Moreover, they reported a fairly high rate of satisfaction: 75% of the patients were satisfied or very satisfied. However, the authors also found a high rate of complications (41%). The most common of these was dislocation, which occurred in eleven (34%) of the thirty-two patients. Seven of these eleven patients underwent revision surgery. Three others with a dislocation chose not to undergo further surgery, which led to poor functional results. In one patient, the shoulder remained stable after closed reduction. In addition, infection occurred in four (13%) of the thirty-two patients.
In several studies1-3, authors have reported on the use of standard arthroplasty for the treatment of proximal humeral nonunions, with mixed results. Also, one smaller study of reverse prostheses for the treatment of nonunions (n = 18) has been published4. In a separate article, Boileau et al.1 described a 32% complication rate and low satisfaction with arthroplasty for the treatment of proximal humeral nonunions (type-3 sequelae). In contrast, Duquin et al.2 reported improved flexion and external rotation, similar to the results in the current study, with the use of standard arthroplasties. The prosthesis survived for at least twenty years in 93% of patients. However, <50% of the patients were satisfied. Reoperation occurred in 18%, and 21% had complications. They reported that patients with healed tuberosities had the best results. Lin et al.3 noted a high level of satisfaction and improved functional results in nine of twelve patients who underwent hemiarthroplasty for the treatment of nonunions. In their study, the greater tuberosity was not osteotomized and a medial calcar graft was used in a technique similar to the one used later in the current study (in which the tuberosities are incorporated into the repair). Martinez et al.4 reported on the use of reverse prostheses for the treatment of nonunions of the proximal part of the humerus (n = 18); they noted a complication rate of 27%, with 22% requiring additional surgery (for two dislocations and two infections). However, their dislocation rate was much lower because a larger and/or eccentric glenosphere was used. The current study has a high rate of complications, and it has clinical results that do not appear to be substantially better than the results of these other studies, in which standard arthroplasty was used. This raises the questions of whether the reverse prosthesis is worth the risk and whether there are certain technical aspects that can be performed to lessen the complication rate.
There is much speculation in this study and the other studies about ways to decrease the risk of instability following placement of the reverse prosthesis in this population. In the current study, the authors speculated that removing the tuberosities may lead to increased instability. They now repair the tuberosities to the prosthesis by placing the stem of the prosthesis through the tuberosities during insertion and reinforcing with suture fixation. In ten of their eleven patients with instability, the tuberosities were resected during the early part of the study. In fact, the authors found an association between tuberosity resection and shoulder dislocation (p < 0.007). When possible, they now preserve the tuberosities with a technique similar to the one described by Lin et al.3, and they did show a statistically significant improvement in rate of dislocation since adopting this technique. Martinez et al.4 discussed the use of a larger and/or eccentric glenosphere to improve stability. They also used proximal humeral allograft with cerclage wires in patients who had considerable humeral bone loss. Lengthening the humerus 2 to 3 cm greater than the length of the contralateral humerus to decrease the risk of dislocation has been described as a method to increase stability as well5.
Ultimately, this study confirms that proximal humeral nonunions are very difficult problems with no known best surgical solution at this time. Use of the reverse prosthesis has proven successful in many challenging proximal humeral disorders, and I feel that it will ultimately be the treatment of choice for nonunions. However, because many providers attempt to use reverse prostheses to treat this difficult condition, the complication rate is quite high. Numerous different methods for avoiding the complication of dislocation have been mentioned, which leaves the surgeon with questions regarding the best surgical technique to use. Until these various surgical options have been proven independently in prospective studies, some uncertainty will remain in terms of which technique is best for implanting a reverse prosthesis in these patients. Clearly, the surgeon should not simply resect everything and put in a standard prosthesis. It appears that patients may be best served by trying to preserve the tuberosities, both to improve function and to decrease the rate of dislocation. The surgeon may also encounter fewer dislocations by lengthening the humerus and by considering the use of larger and/or eccentric components supported with allografts along the humerus.
1. Boileau P, Chuinard C, Le Huec JC, Walch G, Trojani C. Proximal humerus fracture sequelae: impact of a new radiographic classification on arthroplasty. Clin Orthop Relat Res. 2006 Jan;442:121-30.
2. Duquin TR, Jacobson JA, Sanchez-Sotelo J, Sperling JW, Cofield RH. Unconstrained shoulder arthroplasty for treatment of proximal humeral nonunions. J Bone Joint Surg Am. 2012 Sep 5;94(17):1610-7.
3. Lin JS, Klepps S, Miller S, Cleeman E, Flatow EL. Effectiveness of replacement arthroplasty with calcar grafting and avoidance of greater tuberosity osteotomy for the treatment of humeral surgical neck nonunions. J Shoulder Elbow Surg. 2006 Jan-Feb;15(1):12-8.
4. Martinez AA, Bejarano C, Carbonel I, Iglesias D, Gil-Albarova J, Herrera A. The treatment of proximal humerus nonunions in older patients with reverse shoulder arthroplasty. Injury. 2012 Dec;43(Suppl 2):S3-6.
5. Lädermann A, Williams MD, Melis B, Hoffmeyer P, Walch G. Objective evaluation of lengthening in reverse shoulder arthroplasty. J Shoulder Elbow Surg. 2009 Jul-Aug;18(4):588-95. Epub 2009 May 28.