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Although the first shoulder arthroplasty was implanted in 1893 by the French surgeon Jules-Emile Pean,[1][1] the development of the procedure came in the 1950s when Neer[2][2] described the results using a vitallium prosthesis to treat comminuted fractures of the head of the humerus. About 20

Forty-three patients (46 shoulders) who underwent shoulder arthroplasty after fracture of the proximal humerus underwent rehabilitation and follow-up at a special reeducation center for an average of 3 months (1–6). The rehabilitation followed the protocol recommended by Neer (recovery of passive joint movements, muscular strengthening and stretching) to which were added hydrotherapy, physiotherapy and occupational therapy. The functional results, assessed after an average follow-up of 19 months, were disappointing with a normalised Constant score of only 60.2%. There appeared to be two factors which explained these poor results. Firstly, the advanced age of the population (52 older than 70) who was often poorly or non-motivated (22%) and debilitated (21% chronic alcoholics) and who had significant medical and neuro-psychiatric histories. Secondly, incompletely resolved anatomical and surgical problems: damage to the circumflex nerve (6.5%), early migration of the greater tuberosity (6.5%), secondary migration with malunion (15%) and/or nonunion (11%) of the greater tuberosity. These anatomical and surgical problems should be suspected clinically in patients who have an abnormally painful shoulder in the immediate postoperative period (16 cases in our series) and later if there is a dissociation between active anterior elevation (deficient) and passive anterior elevation (preserved) or if the range of active movement plateaus or regresses with time (24% and 9% of the patients in this series). The discrepancy between active and passive motion elevation suggests that limited motion is not caused by gleno-humeral scaring but instead by weakness of the deltoid (because of axillary lesion) and/or of the external rotators (because of greater tuberosity migration).

We isolated two types of fractures sequelae of the proximal humerus that can be treated with a shoulder arthroplasty without having to perform a greater tuberosity osteotomy: humeral head collapse or necrosis (40 cases) and chronic dislocation or fracture dislocation (9 cases). These old traumas feature tolerable displacement of the greater tuberosity, which makes an implantation of a humeral component possible while still maintaining continuity of the tuberosity and rotator cuff to the shaft. The Aequalis shoulder prosthesis was used in all cases and was particularly indicated in these challenging post traumatic conditions since it offers the possibility to be adapted to this distorted anatomy. Adjustment of inclination and/or translation of articular prosthetic surface allows some tuberosity osteotomies to be avoided. The risk of nonunion of the greater tuberosity after osteotomy should lead surgeons to abandon the idea to reconstruct a normal anatomy of the proximal humerus at any costs. In these two specific etiologies, the surgeon can accept some deformity of the proximal humerus but with good functional results.

This prospective multicenter study of 71 sequelae of fractures of the proximal humerus treated using a nonconstrained shoulder prosthesis demonstrates that osteotomy of the greater tuberosity is the most important factor for the functional result (p=0.05) because of persistent nonunion and/or bone resorption. This allows two types of fracture sequelae to be distinguished, whose functional results are completely different: (a) Intracapsular, impacted fracture sequelae in which osteotomy of the greater tuberosity is not required. This type of sequelae, in which the greater tuberosity heals to the shaft with a slight malunion, includes cephalic collapse and necrosis (40 cases) and chronic, locked dislocations and fracture-dislocations (9 cases). (b) Extracapsular, disimpacted fracture sequelae in which an implant cannot be inserted without osteotomizing and repositioning the greater tuberosity. This type of sequelae, in which the greater tuberosity is not healed or heals away from the shaft, includes surgical neck non-unions (6 cases) and severe tuberosity malunions (16 cases). The necessity of performing a greater tuberosity osteotomy with the shoulder replacement in a fracture sequelae to reconstruct the proximal humerus should lead the surgeons to anticipate a “limited goal result” with a limited active anterior elevation, below the horizontal, and with residual pain.

Tuberosity osteosynthesis in shoulder arthroplasty remains a challenging problem: there is a high rate of nonunion or malunion and the number of failures is underdiagnosed. Proper synthesis of the tuberosities is closely linked to good positioning of the prosthesis with regard to length and retroversion. Nonunion of the tuberosities may be due to early or secondary bone migration because of malpositioning of the prosthesis and/or poor technique with tuberosity osteosynthesis. Migration of the tuberosities occurs either because there is excessive horizontal tension, if the prosthesis has been positioned in too much retroversion; excessive vertical tension, if the prosthesis has been cemented too high or by excessive oblique tension, if the stem has been cemented in valgus which shifts the upper part laterally, prevents intertuberosity contact, and causes over-tensioning.

Sixty-six patients with acute three and four-part proximal humeral fractures treated with humeral head replacement were reviewed and radiographed with an average follow-up of 19 months (12–57 months). At review, computed tomographic scans were available in 23 patients and scaled radiographs of both humeri were available in 39 patients. The most significant factors associated with a poor functional result were: (a) Migration of the greater tuberosity either posterior (29%) or superior (17%), leading to nonunion, malunion and late bone resorption. (b) Malposition of the prosthesis because of inappropriate length, the prosthesis being too proud (15%) or too low (29%) and/or excessive retroversion (14%). There was a clear correlation between prosthesis positioning and greater tuberosity migration (p=0.001): greater tuberosity migration was the consequence of malpositioning of the humeral prosthesis, particularly when the prosthesis was too proud, too retroverted. Multiple technical errors of prosthesis positioning may be associated and increase the risk of greater tuberosity detachment despite meticulous tuberosity reconstruction with associated bone graft and secure fixation with heavy nonabsorbable sutures. Prosthesis positioning is the key to greater tuberosity healing to the shaft and should be more accurate but is difficult because of the absence of proximal anatomical landmarks in three-and four-part fractures. The Aequalis fracture jig, a new device allowing for more accurate positioning of the prosthesis because of control of the humeral length and retroversion, has been designed because “eyeball” positioning of the prosthesis is insufficient. Its early use seems to be promissing.