Proximal humerus malunions present a unique challenge to the orthopedic surgeon. In addition to the apparent distortion of bony anatomy, significant soft tissue contractures frequently create a challenge in regard to soft tissue balancing at the time of surgery. Malunions of the proximal humerus may result from incomplete reductions at the time of surgery as well as displacement in the postoperative period. Malunions may also result from the acceptance of unsuccessful closed reduction or progressive angulation/displacement during the healing process. The purpose of this tutorial is to discuss the evaluation and management of patients with a proximal humerus malunion.
Classification of Proximal Humeral Malunion
Beredjiklian and colleagues1 proposed a classification system for proximal humeral malunions. They divided malunions into three types:
- Type 1: Malposition of the tuberosities
- Type 2: Incongruity of articular surface
- Type 3: Articular fragment malposition
The authors highlight the fact that significant soft tissue pathology plays a key role in the functional impairment found in malunions. They emphasized that bone and soft tissue pathology must be addressed at the time of surgery to maximize the outcome.
Corrective osteotomy is an option for surgeons who must treat a patient with a proximal humerus malunion. This option may best be considered in a young, active patient who has no radiographic evidence of degenerative changes in the glenohumeral joint. In an older, less active patient who has evidence of degenerative joint disease, a shoulder arthroplasty may be a more suitable and definitive procedure.
Patients with proximal humerus malunions often present with complaints of pain as well as loss of function. Frequently, patients have impingement-type pain due to a malunion of the greater tuberosity with an associated decrease in the subacromial space. Some of the contraindications to a corrective osteotomy include a massive irreparable rotator cuff tear, significant degenerative changes of the articular surfaces, avascular necrosis, active infection, or nerve injury.
Preoperative imaging studies, including true anteroposterior (AP) radiographs in internal and external rotation and an axillary radiograph of the shoulder, are the minimum studies required (Slide 1). Additionally, radiographs of the contralateral shoulder for comparison of the patient’s neck-shaft angle may be obtained. A computed tomography (CT) scan with 3-dimensional reconstructions to assist in preoperative planning is also helpful. Developments in software for CT scans allow the processing of subtraction views (Slide 2 and Slide 3), which allow a surgeon to evaluate the 3-dimensional configuration of the malunion from any angle.
A laterally based closing wedge osteotomy for varus malunions was described by Benegas and researchers.2 They discussed their preoperative planning as well as surgical technique of performing the osteotomy of the proximal humerus. True AP views in external rotation of both shoulders are obtained with careful attention directed at the neck-shaft angle. The surgeon calculates the necessary size of the bone wedge that must be removed to obtain a patient’s normal neck-shaft angle. The authors perform a closing wedge osteotomy followed by internal fixation with a T-plate. The authors also note that an acromioplasty may be performed at the same time to increase the subacromial space.
Limited results are published in regard to the outcome of correctional osteotomy. Five patients with varus malunion treated with valgus osteotomy of the surgical neck with osteosynthesis with plate and screws were reported by Benegas and colleagues.2 Four of the five patients were initially treated nonoperatively. Among the patients in that study, the mean age was 53 years with a mean follow-up of 34 months. At 6 weeks postoperative, union was present in all patients. All the patients were satisfied with their result and had significant improvements in forward elevation and pain relief. Two patients ultimately required hardware removal due to pain with shoulder flexion.
Russo and colleagues3 reported on nineteen patients with posttraumatic malunion who were treated with an osteotomy. The authors noted that three types of osteotomies were performed: tri-planar osteotomy for three- and four-fragment sequelae, osteotomy of the humeral neck for varus deformity, and an isolated osteotomy of the greater tuberosity. There were 14 excellent results and 5 satisfactory results. The authors reported that all patients had improvement in range of motion and pain relief. Non-anatomic positioning of the greater or lesser tuberosity occurred in six patients. The authors note that osteotomy may be an effective treatment option for active patients in whom an arthroplasty would be contraindicated. They also noted that if shoulder arthroplasty is needed in the future, then good repositioning of the tuberosity may facilitate implantation of the prosthesis.
Arthroscopic Treatment of Proximal Humerus Malunion
Arthroscopic treatment of proximal humerus malunions has been reported in the literature. One of the potential benefits of shoulder arthroscopy is the ability to evaluate and treat soft tissue and intra-articular abnormalities. In addition, contractures of the capsule and subacromial impingement can also be addressed at the time of surgery. Beredjiklian and colleagues1 reported on two greater tuberosity malunions treated with arthroscopic acromioplasty. The researchers reported that the indication for acromioplasty is less than 15-mm displacement of the tuberosity. An additional report by Burkhart4 discusses arthroscopic subscapularis tenolysis for treating glenohumeral stiffness following open reduction internal fixation of a displaced proximal humerus fracture.
Arthroplasty for Malunions of Proximal Humerus Fractures
Shoulder arthroplasty for the sequelae of proximal humeral fractures may be the most technically challenging of any shoulder procedure. Many patients present with significant distortion of anatomy, failed instrumentation from prior surgery, as well as marked stiffness. In addition, avascular necrosis with associated articular incongruency may be present with the malunion as well.
The standard approach in these patients is a deltopectoral approach. However, in patients with severe scarring, one may consider an anteromedial approach. The surgeon must meticulously release scar present in the subacromial, subdeltoid, and subcoracoid spaces. The joint capsule is carefully released from the neck of the humerus, as well as around the glenoid rim with great care to protect the axillary nerve. The subscapularis is released from the scapular neck. Z-lengthening of the subscapularis may be considered. However, there is concern about potentially weakening the tendon due to a decrease in the overall tendon thickness. Alternatively, a surgeon may consider a lesser tuberosity osteotomy with the subscapularis attached. The integrity of the rotator cuff integrity is carefully evaluated. If there is instrumentation in place, then it is best not to remove the hardware until the capsule is released and the humerus is dislocated. If the instrumentation is removed first, this may leave a significant stress riser during attempted dislocation with a resultant fracture.
A preoperative CT scan is helpful in determining the proper entry point for preparing the humeral canal. Great lengths are taken to avoid performing an osteotomy of the greater tuberosity. Only if absolutely necessary is a tuberosity osteotomy performed. If a tuberosity osteotomy is performed, after the prosthesis is placed, the tuberosities are fixed both to the implant and the humeral shaft with heavy nonabsorbable sutures. Autologous bone graft may be taken from the humeral head or iliac crest to augment fixation. Acromioplasty may be performed to improve the space under the coracoacromial arch.
Examining the literature for the outcome of shoulder arthroplasty for malunions reveals overall fair results. The results of patients with old trauma are inferior to the results currently obtained in patients with primary osteoarthritis. Pain relief is more dependably achieved postoperatively than restoration of motion. Shoulder arthroplasty for the sequelae of proximal humeral fractures was reported by Mansat and researchers5 on 28 patients. The results were satisfactory in only 64% of patients based on Neer’s criteria. Eight-five percent of patients reported no or slight pain, and the mean active elevation was 107°. Patients with an acromiohumeral distance greater than 8 mm had better results than those who did not. The authors concluded that if an osteotomy of the tuberosity must be performed due to major displacement, then results are unpredictable. The three patients who required a greater tuberosity osteotomy at the time of arthroplasty had an unsatisfactory result.
Boileau and colleagues6 reported on 71 patients who underwent shoulder arthroplasty for sequelae of proximal humerus fractures. There were good to excellent results in 42% of patients. A 27% complication rate included 4 diaphyseal fractures and one metaphyseal fracture. The authors noted that the most significant factor affecting results was the need for greater tuberosity osteotomy. All patients who had a greater tuberosity osteotomy were not able to regain active elevation above 90°. The authors strongly emphasize that arthroplasty for malunions should be performed without a greater tuberosity osteotomy whenever possible (Slide 4 and Slide 5).
Antuna and colleagues7 reported similar results to those found by Boileau. They reported that 10 of 24 shoulders that had a greater tuberosity osteotomy had a complication related to tuberosity nonunion, malunion, or resorption. Implantation of the humeral component in slight varus or valgus to accommodate the tuberosity malunion was not associated with an increased incidence of humeral component loosening. In addition, humeral components with a modified curvature in the stem have been used with success in their experience (Slide 6).
Surgical treatment of proximal humeral malunions is technically challenging. Surgeons may consider corrective osteotomy for proximal humeral malunions in young patients without evidence of degenerative joint disease. Arthroplasty for proximal humerus malunions have fair outcomes due to limitations in shoulder motion, but pain relief is more consistently improved upon. One should avoid a tuberosity osteotomy if at all possible at the time of arthroplasty.
- Beredjiklian PK, Iannotti JP, Norris TR, Williams GR. Operative treatment of malunion of a fracture of the proximal aspect of the humerus. J Bone Joint Surg Am. 1998; 80:1484-1497.
- Benegas E, Zoppi Filho A, Ferreira Filho AA, et al. Surgical treatment of varus malunion of the proximal humerus with valgus osteotomy. J Shoulder Elbow Surg. 2007; 16:55-59.
- Russo R, Vernaglia Lombardi L, Giudice G, Ciccarelli M, Cautiero F. Surgical treatment of sequelae of fractures of the proximal third of the humerus. The role of osteotomies. Chir Organi Mov. 2005; 90:159-169.
- Burkhart SS. Arthroscopic subscapularis tenolysis: A technique for treating refractory glenohumeral stiffness following open reduction and internal fixation of a displaced three-part proximal humerus fracture. Arthroscopy. 1996; 12:87-91.
- Mansat P, Guity MR, Bellumore Y, Mansat M. Shoulder arthroplasty for late sequelae of proximal humeral fractures. J Shoulder Elbow Surg. 2004; 13:305-312.
- Boileau P, Trojani C, Walch G, Krishnan SG, Romeo A, Sinnerton R. Shoulder arthroplasty for the treatment of the sequelae of fractures of the proximal humerus. J Shoulder Elbow Surg. 2001; 10:299-308.
- Antuna SA, Sperling JW, Sanchez-Sotelo J, Cofield RH. Shoulder arthroplasty for proximal humeral malunions: Long-term results. J Shoulder Elbow Surg. 2002; 11:122-129.