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Shoulder arthroplasty for fracture: Indications and technique
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Generally, proximal humerus fractures are the sequelae of low-energy falls in elderly patients or high-velocity trauma in young patients (Figure 1).1-3 Surgical management of these fractures depends on the fracture pattern, including number of fragments and their displacement, bone quality of a patient and the functional demands of a patient.
Indications
Proximal humeral hemiarthroplasty is indicated for displaced three- and four-part fractures in elderly patients, four-part fracture dislocations, head-splitting fractures and fractures that include significant destruction of the articular surface.1,2,4,5 Poor bone quality, which may increase operative difficulty otherwise, does not preclude the use of a cemented arthroplasty technique.
Union of the greater tuberosity in an anatomic position relative to the prosthetic head and humeral shaft is a necessity for active overhead elevation after arthroplasty for fracture. Fracture-specific prosthetic implants have statistically improved the rate of tuberosity healing and consequent functional outcome4 (Figure 2). Pain relief after shoulder arthroplasty for fracture remains predictable after surgery.
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Figures courtesy of Sumant G. Krishnan, MD. |
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Technique
The technical goal of hemiarthroplasty is to recreate a patient’s prefracture anatomy. Preoperative planning includes obtaining scaled radiographs of the fractured and uninjured humeri to delineate humeral height (Figure 3). The tuberosity fragments are measured on a radiograph. In a modified beach-chair position, with the scapula supported, a 2.5-inch to 3-inch deltopectoral approach is used. We have found that a well-placed incision and a mobile soft tissue window will permit the procedure to be performed easily through this limited incision. With a self-retaining retractor holding the deltoid laterally and the conjoint tendon medially, a Hohman retractor is placed above the coracoacromial ligament and a curved retractor is placed above the acromion.
Manipulation of the tuberosity fragments should be kept to a minimum to preserve intact periosteal attachments to the diaphysis. The long head of the biceps is then identified and tagged, and a tenotomy is performed. Typically, the fracture line can be located between the tuberosities, posterior to the bicipital groove. The intertubercular fracture line is followed proximally through either the rotator interval or the rotator cuff medial to the level of the glenoid. Any bleeding from the anterior humeral circumflex artery or its venae commitantes is controlled with electrocautery.
Four horizontal mattress heavy #5 Ethibond (Ethicon, Somerville, NJ) nonabsorbable sutures are placed around the greater tuberosity at the bone-tendon junction (two in the infraspinatus and two in the teres minor). Two temporary stay sutures are placed around the lesser tuberosity at the subscapularis/bone tendon junction. The tuberosities are gently retracted and the length of the greater tuberosity is measured with a ruler. The origin of the long head of the biceps is then excised and the head fragment is removed and measured with a caliper. If the humeral head falls in between sizes, then the smaller size is selected. Structure cancellous bone graft is procured from this articular fragment. Additionally, the glenoid is inspected for defects or significant erosion requiring replacement (rare). The medullary canal is prepared by hand using cylindrical reamers of increasing diameter. An Aequalis fracture stem (TORNIER, St. Ismier, France) of the appropriate diameter with the optimal humeral head size is selected.
Three guides are used to ensure that a patient’s normal humeral height anatomy is being recreated: (1) a marking pen line is placed on the prosthesis; this is the length of the greater tuberosity fragment from the top of the prosthetic humeral head and will delineate how far the stem will be inserted in the medullary canal; (2) this correct depth of insertion will recreate the normal contour of the medial calcar and the “gothic arch” of the proximal medial humerus with the lateral scapular border below the glenoid; and (3) the greater tuberosity, when pulled into its final resting position, will be level or 3 mm to 5 mm inferior to the top of the prosthetic head. Retroversion is selected by facing the prosthetic head toward the glenoid with the forearm in neutral rotation at the side (approximately 20º of retroversion relative to the transepicondylar axis of the elbow).
Two drill holes are placed in the proximal humeral shaft and two Ethibond sutures are placed in these holes in a horizontal mattress fashion to be used as “tension band” sutures for final tuberosity osteosynthesis (Figure 4). The stem is cemented to the predetermined depth and rotation, in slight valgus. A cancellous bone graft wedge is placed in the “window” of the fracture prosthesis, under the greater tuberosity and under the medial edge of the prosthetic head.
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Figures courtesy of Sumant G. Krishnan, MD. |
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Two of the sutures previously placed in a horizontal fashion at the bone-tendon junction of the greater tuberosity are now passed around the prosthetic neck and tied down. The remaining two previously placed horizontal Ethibond sutures are passed around the humeral neck and placed through the subscapularis tendon from posterior, exiting anteriorly and tied down (Figure 5). The transosseous tension band sutures from the humeral shaft are used to create vertical tension on the osteosynthesis complex. One suture is passed anteriorly through the subscapularis tendon and supraspinatus tendons (anterosuperior cuff) while the other suture is passed posteriorly through the infraspinatus and supraspinatus tendons (posterosuperior cuff).
The shoulder is placed through a full range of motion to ensure no micromotion of the tuberosity fragments. Passive intraoperative range of motion should be at least 160º of elevation, 40º of external rotation and 70º of internal rotation. The rotator interval or iatrogenic rotator cuff split is closed with the arm in 20º to 30º of external rotation, and the biceps is tenodesed within the intertubercular groove/rotator interval to soft tissue. Postoperative care involves a sling and passive motion for the first six postoperative weeks.
Conclusion
Proximal humerus fractures can be challenging to manage surgically. Options depend on fracture anatomy, bone quality and patient functional demands. Generally, percutaneous and/or plate fixation osteosynthesis is recommended for young patients with good bone. Hemiarthroplasty is indicated in the low-demand elderly patients with osteoporotic bone and severely displaced articular surface fractures. Regardless of the type of surgical management, attention to detail, knowledge of anatomy and meticulous surgical technique can yield excellent outcomes for pain relief and functional use.
References
- Boileau P, Walch G, Krishnan SG. Tuberosity osteosynthesis and hemiarthroplasty for four-part fractures of the proximal humerus. Tech Shoulder Elbow Surg. 2000;1:96-109.
- Boileau P, Krishnan SG, Tinsi L, et al. Tuberosity malposition and migration: reasons for poor outcomes after hemiarthroplasty for displaced fractures of the proximal humerus. J Shoulder Elbow Surg. 2002;11:401-412.
- Gerber C, Werner CM, Vienne P. Internal fixation of complex fractures of the proximal humerus. J Bone Joint Surg Br. 2004;86:848-855.
- Krishnan SG, Burkhead WZ. Shoulder arthroplasty for fracture: results of anatomical reconstruction and stable tuberosity osteosynthesis. International Congress of Shoulder Surgery, Washington, D.C., 2004.
- Williams GR, Wong KL. Two-part and three-part fractures: open reduction and internal fixation versus closed reduction and percutaneous pinning. Orthop Clin North Am. 2000;31:1-21.