12.2.1 Indications for Hemiarthroplasty

The indications for arthroplasty should be based on both patient characteristics and fracture characteristics. Patients should be medically stable in order to tolerate extensive surgery and be able to actively participate in rehabilitation after surgery. Fracture characteristics include configuration, displacement, and bone quality. Fracture configurations including head-splitting pattern, fracture-dislocations, and displaced three- and four-part fracture and/or dislocation that are not amenable to surgical fixation are the most common indications for arthroplasty (► Fig. 12.1).4,5

Certainly, in some cases there are some clear-cut clinical and pathologic indications for RTSA as opposed to HA. Elderly patients, especially those who are relatively sedentary with medical comorbidities precluding tuberosity healing and/or severe comminution or metaphyseal bone loss, are the prime indicators for RSA at our center

When we correlate the increasing life expectancy with increased activity and demands, arthroplasty indications become less clear. Most patients in this pathologic cohort had normal function prior to injury, so their expectations to return to their normal activities of daily living and sports participation after arthroplasty will be quite high. For these reasons, RTSA may be less desirable in some of these patients due to activity limitations, increasing risks of complication, and less-certain prosthesis longevity.

Based on the above considerations, we utilize HA for many trauma patients who are very active and healthy and in whom ORIF techniques are not indicated. This being said, our own bias in the less-active, more-elderly patient with poor bone quality is to do an RTSA with tuberosity reconstruction.

12.2.2 Surgical Technique

Results of HA for acute trauma are directly related to proper patient selection, technique, and appropriate rehabilitation. Timing of surgery has also been shown to affect outcomes with patients undergoing HA less than 4 weeks after trauma having better outcomes.4,5,6

Proper technique includes placing the humeral component at the proper height and version with the proper sized humeral head component. Krishnan et al14 have showed statistically significant improved results in this patient cohort when a fracture-specific humeral component was utilized. These implants have gradation markings for proper height placement and are designed with a proximal geometry that provides a better milieu for tuberosity healing.

Technique

After adequate regional and general anesthesia has been carried out, the patient is placed in the beach chair position with the head of the bed elevated approximately 45 degrees. The arm is draped free to allow for extension and rotation. A standard deltopectoral approach is used. The bicipital groove is a critical landmark, and once identified, the biceps tendon is tenotomized. The fracture line between the tuberosities is almost always located just posterior to the groove.

The first part of the procedure involves gaining control of the tuberosity fragments. In cases of arthroplasty for three-part fractures, one must be prepared to osteotomize the lesser tuberosity from the humeral head, in essence creating a four-part fracture. The humeral head is removed, after which the greater tuberosity is tagged with three heavy nonabsorbable sutures placed at the bone-tendon interface and the lesser tuberosity is tagged with two heavy sutures. We utilize different-colored sutures to make suture management easier for tuberosity reconstruction later in the case.

Next, the humeral canal is exposed and sequentially reamed for preparation and sizing. Based on physician preference, an intramedullary or an extramedullary positioning device may be used to ensure proper height. Preoperative X-ray films and implant measurements can also be used to assess the component position.4,5 It has been demonstrated that the top of the pectoralis major tendon can also be used to assess height given that it is on average 5.6 cm below the top of the humeral head.15 Measuring any large medial metaphyseal fragments can also help gauge the correct height. Proper humeral component height can also be confirmed with an intraoperative X-ray demonstrating restoration of the so-called gothic arch as described by Krishnan et al.16

Prior to humeral component placement, two drill holes are made 1.5 cm distal to the fracture site on the humeral shaft and then heavy nonabsorbable sutures are passed prior to implant cementing or impaction. One suture is placed longitudinally in the more posterior drill hole from outside to inside going from inferior to superior; this suture will be used later to provisionally fix the greater tuberosity to the fracture stem. The second suture is placed transversely from anterior to posterior and will be used as a figure-of-eight suture through both tuberosities at the end of the procedures after they have been fixed to the stem and each other.

Secure humeral component position and fixation is mandatory and depends on whether the surgeon chooses to use cement or in-growth fixation depending on which implant system is utilized. We utilize a cemented fracture-specific stem (Biomet Comprehensive Fracture Stem, Biomet, Warsaw, IN) that is convertible to RSA if necessary.

Next, the fracture-specific humeral component is cemented or impacted in place at approximately 20 to 30 degrees of retroversion at the correct anatomic height.

Next, a closed reduction is performed with a trial humeral head component to assess the stability. We prefer 50% translation of the head on the glenoid in the anterior, posterior, and inferior directions. Once satisfied, the real proper-sized humeral head component is impacted into place.

As mentioned earlier, in the present state of shoulder arthroplasty technology a humeral component that is convertible to RSA is more desirable in case revision to RSA is needed in the future.

A successful outcome for HA in the fracture patient depends on proper tuberosity reconstruction in an anatomic position. This is initially dependent on proper suture fixation. Systematic suture tying is critical since the high number of sutures used can make their management challenging. First, the middle suture previously placed through the greater tuberosity is brought around the implant and through a slot on the medial side of the implant. Next, the posterior longitudinal suture previously placed through the drill hole in the humeral shaft is now brought around the top of the greater tuberosity. Next, the top and bottom sutures previously placed in the greater tuberosity are brought around the implant through the slot and then inside out through the lesser tuberosity (► Fig. 12.2).

The greater tuberosity is then placed against the anterior fin of the implant and fixed 0.5 cm distal to the top of the humeral head. It also must overhang or “shingle” the proximal humeral component for proper healing. The middle and posterolateral shaft sutures are then tied securely. In essence, this rigidly fixes the greater tuberosity in the proper position and provides stability to allow for proper healing.

Next, the top and bottom sutures through the lesser tuberosity are tied to reduce the lesser to the greater tuberosity. The suture that was placed in the humeral shaft is finally used over the top of the tuberosities in a figure-of-eight fashion (► Fig. 12.3).4,5

A final closed reduction is performed to check the stability of the repair and the range of motion. A minimum of 150 degrees of forward elevation and stable internal and external rotation should be achieved. A portable radiograph can be obtained immediately after the surgery to assess the position of the implant and tuberosities (► Fig. 12.4).

12.2.3 Results

Historically, more than 50% of all shoulder arthroplasties were performed for trauma. This is especially important since in the United States, most of these procedures are done by surgeons with less experience in shoulder arthroplasty. Hammond et al9 have shown that arthroplasty cases done by surgeons with more experience and in hospitals with greater volume had significantly better outcomes.

In more recent years, better understanding of shoulder replacement surgery, improvements in implant technology, and the increased number of experienced shoulder surgeons have increased the number of shoulder reconstructive procedures being performed and have resulted in improved clinical outcomes in most cases. For these reasons, in this era, we can expect better results in all types of shoulder arthroplasties including HA for acute trauma.

In a systematic review, Kontakis et al17 analyzed 810 HA cases in 16 studies with a mean follow-up of 3.7 years. They found complications related to fixation and healing of the tuberosities in 11.15% of patients. While most patients had minimal pain, the mean forward elevation was 105.7 degrees and mean abduction was 92.4 degrees, and most had persistent and significant functional limitations at the final follow-up.17 Liu et al18 noted in a comparative study that younger patients in whom the tuberosities healed had significantly better outcomes than older patients in whom the tuberosities had failed to unite.

Recently, Krishnan et al14 reported a statistically significant improvement in the results of HA for fracture when a fracture-specific implant was utilized. Dines et al5 reported good to excellent results of HA for fracture in a small series of older active patients in whom tuberosity reconstruction and rehabilitation were emphasized.

The outcomes after HA are basically binary with excellent results if the tuberosities heal and poor results if the greater tuberosity does not heal. Liu et al18 reviewed 33 patients undergoing HA for fracture and found that patients with poor tuberosity healing had significantly higher pain scores and lower functional outcomes.

Recently, there have been a number of studies contrasting the results of HA versus RTSA for acute fractures.7,8,9,10,11,12,13 Although the outcomes of RTSA for fracture are comparable to HA, they are less influenced by tuberosity healing.

Garrigues et al8 retrospectively reviewed small groups of HA and RTSA for fractures. The RTSA cohort performed better in terms of forward elevation and patient satisfaction. However, elevation without rotation can be just as disabling as lack of elevation, especially in a fracture patient who had normal function prior to trauma. Clearly, each of these reconstructive procedures is extremely challenging.

HA for fracture is a technically demanding procedure that requires strict attention to detail, including proper component positioning, tuberosity reconstruction, and proper postoperative care. As described earlier, Krishnan et al14 have demonstrated that use of a trauma-specific arthroplasty stem yielded significantly better results than use of a standard component in trauma cases. This concept has now been expanded to include fracture-specific implants that are convertible to RSA if necessary later.

The real issue in this debate comes down to return to function. Unlike other shoulder arthroplasties that are done for severe pain and disability, most trauma patients had normal function prior to injury. This makes the comparative results difficult to evaluate, especially in an aging population that remains highly active and high functioning. In previously reported surveys of elite shoulder surgeons about activities that they allow after shoulder arthroplasty, the limitations in weight-bearing and functional activities were significantly higher in the RTSA group compared to both the TSA and HA groups.19,20

When you combine these observations with the fact that most trauma patients have expectations of a return to their “normal” activities and function, one may conclude that RTSA may not be the best alternative in all trauma patients. This concept is strengthened by the outcomes of some comparative studies that indicate that HA with anatomic tuberosity reconstruction and healing had the best functional outcomes. Therefore, those trauma patients with tuberosity bone stock and fracture configurations amenable to reconstruction should undergo HA with tuberosity reconstruction for best possible functional return.