Master Techniques in Orthopaedic Surgery: Fractures
2nd Edition

4
Proximal Humeral Fractures: Arthroplasty
Louis U. Bigliani
Sean F. Bak
Steven S. Goldberg
Indications/Contraindications
Proximal humeral replacement is a useful surgical technique for acute displaced fractures of the proximal humerus (Fig. 4.1). The indications for placement of a prosthesis are (a) 4-part fractures and fracture dislocations, (b) head-splitting fractures, (c) impression fractures involving more than 40% of the articular surface, and (d) selected 3-part fractures in older patients with osteoporotic bone. The majority of severely displaced, proximal, humeral fractures occur in the older population, with predominance in women. Other methods of treatment, including closed reduction, open reduction-internal fixation, head excision, and fusion, have been reported to have a high percentage of unsatisfactory results.
The contraindications for proximal humeral replacement are active soft-tissue infection, chronic osteomyelitis, and paralysis of the rotator-cuff muscles. Deltoid paralysis is not a contraindication: Adequate yet compromised function can be achieved in such a shoulder.
Preoperative Planning
A detailed history and physical are essential, although an adequate clinical evaluation of the injured limb may be difficult because of pain and swelling. It is important to establish whether the patient has lost consciousness or has had a seizure. Neurovascular status should be assessed with a high index of suspicion for injuries to the axillary nerve and artery. Injuries to the axillary artery are limb threatening and should be evaluated with emergency arteriography and a vascular surgery consultation. Injuries to the brachial plexus or peripheral nerves are often overlooked initially. The vast majority of these are treated conservatively. Electromyographic analysis should be planned 3 to 4 weeks after injury to help clarify the extent of the injury. A neurologic deficiency should not delay definitive management of the fracture. Most injuries are neurapraxias and will resolve over time sufficiently to allow adequate function. If the neurologic status does not improve, any needed procedure to the axillary nerve can be done within 3 months of injury without compromise.
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To determine whether a humeral head replacement is the best treatment option for a displaced, proximal, humeral fracture, the fracture pattern must be clearly delineated. In the majority of cases, this can be achieved with a trauma series (Fig. 4.2). This includes a true anteroposterior (AP) view of the scapula (taken 30 to 40 degrees oblique to the coronal plane of the body), a transscapular lateral or Y view, and an axillary view. The axillary view is taken by abducting the arm 20 to 30 degrees and placing the tube in the axilla with the radiographic plate above the shoulder; there is no need to abduct the arm fully. Often the surgeon must position the arm because of pain. Alternately, a Velpeau axillary view can be obtained, with the patient remaining in the sling and leaning back over the plate and the tube directed downward. If displacement cannot be determined, or if the articular surfaces of the humeral head or glenoid are not clearly visualized, then a computed tomography (CT) scan also may be used to clarify the situation. Use of a preoperative scanogram of both the involved and the uninvolved arm often helps establish the proper length of the prosthesis relative to the remaining humeral shaft.
Figure 4.1. A four-part fracture of the proximal humerus. The humeral head is free floating and displaced from both tuberosities and the shaft. The lesser tuberosity fragment is pulled medially by the subscapularis; the greater-tuberosity fragment is pulled posteriorly and superiorly by the supraspinatus and infraspinatus; the shaft fragment is pulled medially by the pectoralis major.
Surgery
Patient Positioning
Proper patient positioning is the first step to a successful procedure, and its importance cannot be overemphasized. The goal is to have global access to the shoulder. This is achieved by having the involved shoulder elevated from the table and properly supported. We prefer a table with a cutaway section at the shoulder that allows greater access posteriorly and has an attached pneumatic arm positioner (Spider, Tenet Medical, Calgary,
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Alberta, Canada) (Fig. 4.3). Our anesthetic of choice is an interscalene regional block because it provides excellent muscle relaxation, which facilitates exposure. Two small towels are placed under the medial border of the scapula to negate any retraction. The head is secured in a positioner in neutral rotation and flexion with respect to the cervical spine. The operating table should then be placed in a modified beach-chair position. The patient is first flexed fully at the hips, and the foot of the table is lowered to slightly flex the knees. The back of the operating table is then elevated so that the patient sits up at an angle of approximately 45 to 50 degrees. Surgical drapes are used to isolate the operative field superiorly to the midclavicle and inferiorly below the axilla so that the arm can be draped free and is able to be moved throughout the surgery.
Figure 4.2. A. AP radiograph of a 4-part fracture. B. Lateral view in the scapular plane. C. Axillary view.
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Technique
Approach
A long deltopectoral approach is performed, starting just below the clavicle and extending over the lateral aspect of the coracoid to the deltoid insertion on the humeral shaft (Fig. 4.4). Large Gelpi retractors can be placed in the skin to provide exposure. The cephalic vein is identified in the deltopectoral interval and is usually retracted laterally. There are fewer tributary veins on the medial side than on the lateral side, so retracting the vein laterally decreases bleeding. Often, however, there is a large crossover vein superiorly, which should be cauterized so that superior exposure is not compromised. It is important to preserve the deltoid origin
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on the clavicle and acromion. Rarely is the deltoid origin removed. If more exposure is needed, the deltoid insertion may be partially elevated; however, the proximal third of the pectoralis insertion is usually detached from its humeral attachment (Fig. 4.5). This should be tagged with a suture and reattached during closure. At this stage, the coracoid and coracoid muscles should be identified. The coracoid is the lighthouse to the shoulder, and dissection should not be medial to this structure (Fig. 4.6). A
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broad retractor is placed beneath the lateral borders of the coracoid muscles. The coracoid muscles should not be cut nor the coracoid process osteotomized because they provide a barrier to protect the neurovascular bundle. The anterior portion of the leading edge of the coracoacromial ligament can be resected to facilitate exposure. The bulk of this ligament should remain intact to avoid any compromise in superior stability. Another retractor is placed underneath the deltoid and the muscle is retracted laterally. The long head of the biceps should be identified distally and followed proximally, as this is an important structure that will lead to the center of the shoulder at its glenoid insertion (Fig. 4.7).
Figure 4.3. A. The patient is placed in a modified beach-chair position with the back flexed approximately 40 to 50 degrees, and the lateral border of the scapula is at the edge of the table. B. A pneumatic arm positioner can be used for hands-free universal positioning of the upper limb during the procedure.
Figure 4.4. A long deltopectoral approach starts just below the clavicle and extends over the lateral aspect of the coracoid to the deltoid insertion on the humeral shaft.
Figure 4.5. The superior insertion of the pectoralis major is usually detached and tagged to allow improved exposure.
Figure 4.6. The coracoid should be readily identified (tip of clamp), and dissection should not proceed medial to it. The leading edge of the coracoacromial ligament may be resected to improve exposure of rotator cuff muscles.
Exposure of the Fracture
Once the retractors have been placed in the appropriate position, hemorrhagic bursa and fracture hematoma can be identified and gently removed.
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It is important not to remove large pieces of bone that may be used later to support the prosthesis on the deficient proximal shaft. The key to recognizing the various components of the fracture is the long head of the biceps. As the biceps is followed proximally, the lesser tuberosity is on the medial side, and the greater tuberosity is usually on the lateral side (see Fig. 4.1).
As a rule, the rotator interval can be split in the area of the bicipital groove, as this is often fractured. This split can be carried proximally to help identify and mobilize the supraspinatus and subscapularis because they attach to the greater and lesser tuberosities, respectively. The interval is repaired later. The head usually lies between the tuberosities and is removed and used for sizing of the prosthetic head (Fig. 4.8).
If the head has been dislocated laterally, the greater and lesser tuberosities act almost as a hood and can be elevated intact. In this situation, the head can be extracted and the prosthesis can be placed without disturbing the rotator interval, greater-tuberosity, or lesser-tuberosity fragments. Generally, however, the interval must be opened in the area of the bicipital groove. Once again, it is important to preserve any loose fragments and pieces of bone to be used later in the procedure.
The biceps tendon should be preserved and tagged with a nonabsorbable suture. Both tuberosities are then mobilized and tagged with a no. 2, heavy, nonabsorbable suture. We prefer to use swedged-on needles and place them into the tendon at the tuberosity insertion. This preserves the integrity of the remaining bone attached to the tendon and avoids fragmentation of the tuberosity. Thorough mobilization superiorly and medially is important to allow secure fixation of the tuberosities, though this is often a tedious process as a significant amount of hemorrhagic subacromial bursa often obscures the tuberosities and rotator cuff. Often, superior exposure may be limited by the leading edge of the anterior fascicle of the coracoacromial ligament which, as mentioned previously, can be resected.
Figure 4.7. The tendon of the long head of the biceps should be identified and followed proximally because this will help to differentiate between the lesser and greater tuberosities and the area of the rotator interval. If possible, the long head of the biceps should be preserved to act as a head depressor.
Figure 4.8. A. The humeral head is usually a free-floating fragment that can easily be removed by using a metal finger. It is important to evaluate the head for any soft-tissue insertion. B. A relatively intact head can be used to size the prosthetic head. The head may also be used as bone graft if needed or to support the prosthesis.
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This is a good time to evaluate the patient for subacromial impingement. If there is a large subacromial spur in the ligament, or if the patient has an impingement configuration of the acromion, it may be worthwhile to perform an anterior acromioplasty. This is not a routine part of the procedure. Also at this stage, the rotator cuff should be examined for tears. Generally, the rotator cuff is intact in patients with subacromial impingement.
If there is an anterior dislocation of the humeral head below the coracoid and under the coracoid muscles, this should be slowly and carefully dissected, especially if there has been more than a week’s delay in performing the procedure. Significant adhesions and scarring are invariably present and the sharp edges of the fractured head have the potential to injure the vital structures in this region if extraction is forceful or blind. In this instance, very gentle blunt dissection should be done from lateral to medial. Avoid placing any sharp instruments medial to the head without direct visualization. We prefer to use blunt retractors in this situation to avoid injuring the neurovascular bundle. If the head segment has been displaced posteriorly, the shaft and greater tuberosity are gently and laterally retracted so that the head can be removed. If the head is scarred posteriorly, it may need to be osteotomized into segments to facilitate removal.
Shaft Preparation and Prosthesis Placement
The proximal shaft of the humerus should be dealt with in a very gentle manner. The bone is often osteoporotic, and there may be a nondisplaced fracture of the shaft, which should not be disturbed. If a shaft component to the fracture is found, it is important to secure the shaft before prosthesis placement. This can usually be achieved with a cerclage wire and heavy nonabsorbable sutures. Canal preparation and stem implantation are carefully performed to avoid disrupting the repaired shaft. Successful placement of the humeral component supplements the shaft fixation and yields a solidly fixed construct.
Prior to preparation of the shaft, the arm is placed into extension and external rotation, delivering the shaft into the wound. The medullary canal is prepared with rasps and reamers (Fig. 4.9). In most general situations, there is not sufficient bone stock distally or support
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proximally to allow a press fit and cement is therefore necessary. In addition, with both tuberosities fractured, rotational stability of the implant is lost. The proximal part of the humerus should be prepared with drill holes to allow tuberosity fixation with heavy, nonabsorbable sutures. Three or 4 holes should be placed in the area of the greater tuberosity (Fig. 4.10). We like to place no. 2 or no. 5 sutures with a swedged-on needle through the shaft. These sutures are then tagged with a clamp.
Figure 4.9. The medullary canal is prepared with rasps and reamers for cement fixation.
The next step is determination of proper prosthesis configuration. This involves three components: retroversion, height, and head size. Men tend to require a larger head size, and women, a smaller head size. We use the Bigliani/Flatow prosthesis (Zimmer, Inc., Warsaw, IN), which has multiple sizes with a choice of either standard or offset heads. We prefer the offset head because the humeral canal (and therefore the humeral implant) is offset from the center of the native head and better reproduces normal anatomy. Head size may be gauged by taking a radiograph of the contralateral shoulder or by using the head that was removed (if intact) for measurement. It is important, however, not to overstuff the joint as this may result in stiffness or subscapularis rupture.
The stem should not be seated so deeply that the head is placed against the remaining proximal shaft because such a placement will usually decrease the length of the humerus and effectively shorten the deltoid. In most general circumstances, the humeral head should be elevated above the proximal shaft to a position that will allow space for both the greater and the lesser tuberosities to be placed underneath the head. This is crucial. The system has sponges of different diameter that can be placed around the stem to support the shaft in the canal. Then a fin clamp is attached to the anterior fin of the prosthesis and securely holds it at the desired height and rotation on the shaft by way of metal pins or an outrigger that projects off the clamp (Fig. 4.11). This height is determined either by preoperative templating against the contralateral limb or by using intraoperative soft-tissue tension as a guide. The tension on the biceps tendon, if the tendon has been preserved, can act as a guide to the proper tension of the entire myofascial sleeve. If the prosthesis is inserted so deeply that the biceps is very slack in its anatomic position, then often the prosthesis has been placed too deeply into the medullary canal. A biceps tendon that is excessively taut usually indicates that the prosthesis is too proud. If the tuberosities are not placed below the head
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of the prosthesis, impingement will occur. Also, these tuberosities must be attached to the proximal shaft. If extra bone has been saved, it should be used between the prosthesis and the shaft before cementing.
Figure 4.10. Drill holes should be placed in the proximal shaft for attachment of the tuberosities before cementing in the prosthesis. Three to 4 drill holes are placed in the greater tuberosity, and 1 to 2 holes in the lesser tuberosity.
Figure 4.11. A. Sponge placed around the stem of the prosthesis will support the implant in the canal allowing for assessment of height and version. B. The fin clamp is attached to the prosthesis and the outrigger maintains the prosthesis at the desired height. The outrigger also can be attached by way of metal pins (not pictured).
The third important component is the determination of the proper amount of retroversion. A rule of thumb is that the lateral fin of the prosthesis should be in the area of the bicipital groove. Often the majority of the bicipital groove is not present in fractures, but sometimes the distal part of the groove may be identified. Version rods can be attached to the humeral insertion tool or to the fin clamp (see Fig. 4.11). These can be used as reference for the forearm with the elbow flexed to 90 degrees, and in most patients, 30 degrees of retroversion is appropriate (Fig. 4.12). The fin clamp is used to hold the prosthesis at the desired height and rotation during the trial reduction. The head of the prosthesis is reduced on the glenoid to allow internal and external rotation to be assessed. If the prosthesis appears to be stable with 40 to 50 degrees of external rotation and internal rotation with the arm at the side, then the retroversion is adequate. If there has been a posterior-fracture dislocation, then the retroversion may be decreased by 5 to 10 degrees. If there is an anterior-fracture dislocation, then the retroversion may be increased by 5 to 10 degrees. Therefore, as a rule, the retroversion should never be less than 20 or more than 40 degrees. At this stage, the prosthesis can be cemented into place with the shaft properly supported (Fig. 4.13). It is important to make sure that the nonabsorbable sutures are through the holes in the proximal shaft prior to cementing.
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Tuberosity Repair
Tuberosity repair is the next important step. Tuberosity migration is one of the most common causes of failure of the procedure. The tuberosities must be attached to both the fin of the prosthesis and to the shaft of the proximal bone (Fig. 4.14). The nonabsorbable sutures that have been placed proximal to the tuberosities in the tendon can be used to mobilize the tendons and bring them forward. We generally reattach the greater tuberosity first, using 3 to 4 heavy nonabsorbable sutures. Next, the lesser tuberosity is fixed with two heavy sutures. The two sutures are placed through the fin of the prosthesis to both tuberosities and tightened. The arm should be supported in a slightly flexed and abducted position. The biceps tendon that has been preserved is now placed in its groove. The rotator interval that has been opened is now closed above the biceps tendon, so that the biceps tendon comes out at the distal aspect, which is now the bicipital groove (Fig. 4.15). At this point, the arm is gently internally and externally rotated and flexed to test the stability of the tuberosity repair. The proximal humerus and tuberosities should be moving as a single unit.
Figure 4.12. Version rods attach to the insertion device and reference off the forearm. One rod corresponds to 20 degrees of retroversion with the other at 40 degrees. Typically, the forearm should be oriented between these 2 rods to achieve 30 degrees of retroversion.
Figure 4.13. The stem is cemented into place to provide axial and rotational support.
Closure
A closed, suction drain should be used if there is any residual bleeding. These should exit laterally in the proximal deltoid to avoid injury to the axillary nerve. Drains are usually removed on the first postoperative day. The insertion of the pectoralis major should be repaired (Fig. 4.16). Multiple sutures should then be placed in the deltopectoral interval, and the skin is closed in a subcuticular fashion (Fig. 4.17). Steri-Strips are used to promote a cosmetic scar.
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Postoperative Management
Proper postoperative rehabilitation is essential because adequate motion of the shoulder is required for optimal function. The patient’s ability to participate in the physical therapy and to understand the restrictions on activity are crucial. In general, the goals are to perform early passive motion until the fracture has healed and then to begin strengthening exercises. Radiographs should be taken in the recovery room, at 1 week, 6 weeks, 3 months, and 1 year.
Figure 4.14. Tuberosity repair is an essential part of the procedure. A. Both tuberosities should be attached to the shaft and also to each other through the fin of the prosthesis. B. The tuberosities should move as a unit with the shaft after final repair.
Passive motion is begun early, usually on the first postoperative day. Based on the intraoperative assessment of stability after the tuberosity reconstruction, the surgeon determines the limits of early motion. Consideration is given to the quality of bone, the status of the rotator cuff muscles and the deltoid, and the strength of the tuberosity fixation to the shaft and the prosthesis. On the first day, the surgeon usually passively elevates the arm in the scapular plane to approximately 80 to 90 degrees. On the second day, gravity-assisted pendulum exercises are done first to allow warm-up and obtain the patient’s confidence. After this, passive forward elevation and supine external rotation with a stick are performed. The patient, after gaining some early motion with the help of a therapist, may lie supine and raise the arm by using the uninvolved contralateral arm. These 3 exercises are generally done for the first 6 weeks until adequate tuberosity healing has occurred. The
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goal before discharge from the hospital should be 130 degrees of forward elevation in the scapular plane and 30 degrees of external rotation.
Figure 4.15. The biceps tendon should be preserved and placed in the rotator interval area.
Figure 4.16. A meticulous deltoid closure with repair of the pectoralis major insertion should be performed.
Radiographs should be taken before discharge to confirm that tuberosity displacement has not occurred. Furthermore, radiographs should be repeated at 6 weeks to assess tuberosity healing. When evidence of tuberosity healing is found at approximately 6 to 8 weeks, active assistive elevation with a pulley and isometric strengthening exercises for the rotator cuff and deltoid are initiated. Two to 3 weeks after this, progressive resistive and strengthening exercises are added. Activities of daily living such as personal hygiene and eating are allowed, and these help to build early muscle strength and endurance. Gentle strengthening is an important part of the prolonged physical therapy program. The patient is encouraged to perform the exercises on a daily basis for at least 6 months, preferably 1 year, to achieve optimal results.
Figure 4.17. A subcuticular skin closure is performed.
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The overall success of prosthetic replacement for humeral fractures depends on proper evaluation, surgical technique, and rehabilitation. If proper steps are followed, this procedure is highly successful, with a large percentage of satisfactory results. In a series of humeral head replacements performed at our hospital, 95% of patients had adequate pain relief, with 73% being essentially pain free. Overall, 82% of patients had a satisfactory result, and 18% had an unsatisfactory result. The impact on favorable or unfavorable results depends predominantly on the range of motion achieved by the patient rather than the degree of pain. The majority of failures reflected weakness and inability to raise the arm above horizontal. In addition, the single most important variable in a patient’s ability to achieve a satisfactory result was found to be patient compliance in the postoperative rehabilitation program. Thus, that at the end of 1 year after prosthetic insertion for a 4-part fracture, most patients will be free of pain but will have variable range of motion and strength, often dependent on the adequacy of their rehabilitation.
Complications
Complications after proximal humeral replacement are not uncommon and in most instances can be directly related to failure of technique. Among the most common complications reported are tuberosity displacement, prosthesis problems, stiffness, and infection.
Tuberosity Displacement
The greater tuberosity is more likely to be displaced than is the lesser tuberosity, and it is most often found in older patient with osteopenic bone. Greater-tuberosity displacement is much more problematic because the attached supraspinatus, infraspinatus, and teres minor are critical for satisfactory motion and strength in the shoulder. In addition, with superior displacement of the greater tuberosity, motion may be mechanically blocked because the tuberosity occupies a portion of the subacromial space. If migration of the greater tuberosity happens postoperatively, then consideration should be given to early reattachment and regrafting. Although displacement of the lesser tuberosity occurs, it is not so problematic because other muscles can compensate for associated weakness of the subscapularis. Significant displacement can result in a mechanical block because the arm is internally rotated. In addition, wide displacement of the lesser tuberosity with the attached subscapularis may result in postoperative anterior instability.
The critical factor in eliminating tuberosity displacement is healing of the tuberosity to the shaft of the humerus. In patients adequately protected from postoperative active motion, secure fixation of the greater tuberosity to both the prosthesis and the shaft of the humerus, combined with bone graft between the tuberosity and shaft, will maximize the potential for tuberosity-shaft healing. We have recently used a trabecular metal (TM) proximal-humeral fracture prosthesis. The TM prosthesis features a metal surface designed for bony ingrowth in the proximal metaphysis including the sites of tuberosity attachment (Fig. 4.18). We have had excellent results using this in revisions for tuberosity nonunions and malunions, and we have also begun using it for primary proximal-humeral replacements in patients with marked osteopenia.
Whereas nonunion is often a far greater problem in terms of motion and strength, malunion of the greater tuberosity, either superiorly or posteriorly, frequently results in pain, either from impingement in the subacromial space or from the mechanical block caused by the displaced tuberosity. If the patient is symptomatic and malunion exists, strong consideration should be given to osteotomy and repositioning of the tuberosity.
Prosthetic Loosening
The bony support in the proximal humerus is often not ideal because of osteopenia. With loss of the rotational stability of the implant because of loosening, the version of the prosthesis may have changed and secondary pain, instability, or destruction of the
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previously normal glenoid. Whereas loosening caused by poor bone stock in an uncemented implant could have been avoided if cement had been used at implantation, loosening also may occur with a cemented implant. Because aseptic loosening of the humeral component is rare, the workup should include examination for infection. Revision of the prosthesis should be considered in the event of symptomatic loosening.
Figure 4.18. The TM humeral prosthesis has a proximal metal surface that promotes ingrowth of tuberosities.
Malposition of the Prosthesis
Malposition may involve abnormal version, an abnormally proud prosthesis, or an abnormal depth of prosthesis. Mistakes made by cementing the implant in abnormal version are common because the landmark for correct version, the bicipital groove, is usually involved in the fracture. Three basic guides can be used to place the prosthesis in the proper amount of retroversion (20 to 40 degrees):
  • The prosthetic fin should be placed just lateral to the bicipital groove.
  • The prosthetic fin should be 20 to 40 degrees retroverted relative to the forearm, as judged by version rods on the prosthesis inserter corresponding to 20 and 40 degrees.
  • With the elbow bent 90 degrees and the arm at the side in 0 degrees of internal or external rotation, the implanted humeral head should face directly toward the glenoid fossa.
If the malpositioned prosthesis is too proud, impingement against the residual glenoid fossa may be found. If the humeral head is inserted too deeply into the intramedullary canal, instability of the humeral head may result because of inadequate tension of the deltoid. In addition, an overly deep insertion of the prosthesis makes the greater tuberosity relatively proud and may result in greater-tuberosity impingement on the acromion.
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Postoperative Stiffness
Postoperative stiffness is an important complication because it is almost entirely preventable. Attention to the details of surgery, early, postoperative, passive motion, and patient cooperation with rehabilitation all play critical roles in avoiding postoperative stiffness. It must be emphasized to the patients that lack of compliance or understanding of the postoperative rehabilitation program is the single most common factor associated with rehabilitation failure and postoperative stiffness.
Infection
Infection is an uncommon complication, but it poses significant problems and a long treatment course before resolution. The final result after treatment of an infected prosthesis is frequently less than optimal.
Recommended Reading
Bigliani LU. Proximal humerus fractures. In: Post M, Bigliani LU, Flatow EL, et al, eds. The shoulder: operative technique. Baltimore: Lipincott, Williams & Wilkins; 1998.
Bloom MH, Obata WG. Diagnosis of posterior dislocation of the shoulder with use of Velpeau axillary and angle-up roentgenographic views. J Bone Joint Surg Am 1967;49:943–949.
Hughes M, Neer CS. Glenohumeral joint replacement and post-operative rehabilitation. Phys Ther 1975;55:850–858.
Lervick GN, Carroll RM, Levine WN. Complications after hemiarthroplasty for fractures of the proximal humerus. In: Ferlic DC. Instructional course lectures. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2003.
Levine WN, Blaine TA, Bigliani LU. Fractures of the proximal humerus. In: Rockwood CA, Matsen FA, Wirth MA, et al, eds. The shoulder. Philadelphia: Elsevier; 2004.
Murthi AM, Bigliani LU. Humeral head replacement for four-part proximal humerus fractures. In: Levine WN, Marra G, Bigliani LU, eds. Fractures of the shoulder girdle. New York: Marcel Dekker; 2003.
Neer CS II. Articular replacement of the humeral head. J Bone Joint Surg Am 1955;37:215–228.
Neer CS II. Displaced proximal humerus fractures, Part I. J Bone Joint Surg Am 1970;52:1077–1089.
Neer CS II. Displaced proximal humerus fractures, Part II. J Bone Joint Surg Am 1970;52:1090–1103.
Neer CS II, McIlveen SJ. Remplacement de la tete humerale avec reconstruction des tuberosities et de la coiffe dans les fractures desplacees a 4 fragments. Resultats actuels et techniques. Rev Chir Orthop 1988;74(SII):31–40.
Tanner MW, Cofield RH. Prosthetic arthroplasty for fractures and fracture-dislocations of the proximal humerus. Clin Orthop 1983;179:116–128.