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Year : 2015 | Volume
: 9
| Issue : 4 | Page : 131-134 |
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CASE REPORT Posterior shoulder instability following anatomic total shoulder arthroplasty: A case report and review of management
Joseph W Galvin1, Josef K Eichinger1, Robert E Boykin2, Gregor Szöllösy3, Laurent Lafosse3
1 Orthopaedic Surgery Service, Department of Surgery, Madigan Army Medical Center, Tacoma, WA, USA 2 Blue Ridge Bone and Joint Clinic, Asheville, NC, France 3 Clinique Générale, Alps Surgery Institute, Annecy, France
Correspondence Address: Josef K Eichinger 9040 Fitzsimmons Drive, Tacoma, WA 98431 USA
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DOI: 10.4103/0973-6042.167955
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Date of Web Publication | 22-Oct-2015 |
Abstract | | |
We report a case of posterior shoulder instability following anatomic total shoulder arthroplasty (TSA). In addition, we present guidelines to aid in the management of posterior instability after TSA. A 50-year-old male underwent anatomic TSA for glenohumeral osteoarthritis. Postoperatively, the patient developed posterior instability secondary to glenoid retroversion. He did not improve despite conservative treatment. He underwent an arthroscopic posterior bone block procedure, 4-month after his index arthroplasty. At 14-month follow-up, the patient had regained near full motion and strength, and radiographs demonstrated osseous integration with no evidence of component loosening. Posterior instability following TSA is a relatively rare complication and challenging to manage. The posterior, arthroscopic iliac crest bone block grafting procedure represents a treatment option for posterior instability in the setting of a stable glenoid prosthesis following TSA.
Keywords: Arthroplasty, arthroscopic bone block, glenoid, posterior instability, retroversion, shoulder
How to cite this article: Galvin JW, Eichinger JK, Boykin RE, Szöllösy G, Lafosse L. Posterior shoulder instability following anatomic total shoulder arthroplasty: A case report and review of management. Int J Shoulder Surg 2015;9:131-4 |
Introduction | | ![Top](/ServeContent?url=http%3A%2F%2Fwww.internationalshoulderjournal.org%2Fimages%2Farrow_top.gif) |
Posterior instability after total shoulder arthroplasty (TSA) is a reported complication and can occur for a variety of reasons. [1],[2] Factors related to the development of this condition include glenoid and humeral retroversion, glenoid component loosening, soft tissue imbalance, and rotator cuff tears. [2],[3],[4] In a cohort of TSA's performed at the Mayo clinic, posterior instability was described in 1.8% of cases. [2] Because of the low reported incidence after anatomic TSA, the methods of treatment are likewise not well studied. Treatment options for posterior instability are dependent on the causes of the instability, and the outcomes for revision surgery demonstrate a moderately high rate of failure. [2] A thorough evaluation is required to determine the potential etiology of the instability before any revision surgical procedure is contemplated. We present guidelines to aid in the diagnosis, cause, severity, and treatment options of posterior instability. In addition, we present a novel treatment method for a case of posterior instability with glenoid retroversion and a well-fixed glenoid component treated with an arthroscopic posterior bone block procedure.
Case Report | | ![Top](/ServeContent?url=http%3A%2F%2Fwww.internationalshoulderjournal.org%2Fimages%2Farrow_top.gif) |
A 50-year-old male house painter with longstanding shoulder pain and glenohumeral arthritis refractory to conservative management underwent a TSA with press-fit humeral stem (Global Unite, Depuy, Warsaw, IN, USA) and uncemented glenoid component (Anchor Peg Glenoid, Depuy, Warsaw, IN, USA) in his nondominant extremity. His preoperative imaging revealed a biconcave glenoid with 20° of glenoid retroversion and posterior subluxation of the humeral head [Figure 1]a. Intraoperatively, the anterior glenoid was reamed preferentially in an attempt to correct the posterior retroversion of the biconcave glenoid prior to placement of the glenoid component. Postoperative imaging revealed a well-fixed glenoid component with persistent 20° of retroversion [Figure 1]b. The humeral component was placed according the native humeral version. Intra-operative examination following component implantation revealed a stable glenohumeral joint and no additional corrections or modifications were performed. Postoperatively, the patient had a sense of instability coupled with pain and weakness. While he did not experience frank dislocation episodes, the pain and dysfunction prevented him from returning to work. His examination revealed posterior apprehension, but normal strength of both the deltoid and rotator cuff musculature. He did not improve despite 2 months of dedicated physical therapy. Given the clinical history, imaging and exam findings, the patient was diagnosed with posterior instability as a result of glenoid retroversion.
Potential options for treatment in this situation included revision of the glenoid component with bone grafting or placement of a posterior bone block with retention of the glenoid component. Given the amount of morbidity involved in a revision surgery, a less invasive and alternative method of treatment was chosen. An arthroscopic posterior bone block procedure was performed using an iliac crest graft.
Four months following his index arthroplasty surgery, the patient returned for revision surgery. He was placed in the beach chair position. A 25 mm × 10 mm × 10 mm tri-cortical bone graft was harvested and prepared. Shoulder arthroscopy was then performed using standard portals. Verification of glenoid fixation was confirmed, and a horizontal slit in the posterior rotator cuff muscles was performed. In addition, the bone on the posterior glenoid was prepared to a flat surface with an arthroscopic burr [Figure 2]a. Utilizing a custom double cannula instrument (DePuy-Mitek, Raynham, MA, USA), the graft was advanced through the widened posterior portal [Figure 2]b. Graft was then precisely placed on the posterior glenoid with the surface of the bone block placed parallel and flush with the surface of the glenoid prosthesis [Figure 3]a. Fixation of the bone block was performed with two parallel, cannulated, titanium, 3.5 mm screws. Given the existing Anchor Peg Glenoid component (Dupuy, Raynham, MA, USA) relies heavily on the central peg, care was taken to ensure that both screws lie below the equator of the glenoid prosthesis [Figure 3]b. This was critical as damage to the central peg risks compromising the fixation of the glenoid component. By placing the 10 mm wide graft flush with the size 48 mm glenoid, the anterior to posterior articular surface area was effectively increased by 37%.
At 14-month postoperatively from the bone block procedure, the patient regained near full motion and strength. He has no sense of pain or instability with resisted forward flexion with his arm in an adducted and internally rotated position [Figure 4]a. The patient's subjective shoulder value is 80, with a 2 out of 10 pain score. Imaging obtained at 14-month revealed osseous integration of the bone block to the posterior glenoid, no evidence of glenoid prosthesis loosening and an intact central peg [Figure 4]b.
Discussion | | ![Top](/ServeContent?url=http%3A%2F%2Fwww.internationalshoulderjournal.org%2Fimages%2Farrow_top.gif) |
Instability in the setting of TSA is well described in the literature. In a large review, instability was noted in 5.2% of the cases and was the most common complication of the procedure, however, isolated posterior instability is felt to be relatively rare. [3] The type of instability is classified by the direction (superior, inferior, anterior, and posterior), and the etiology is often multifactorial. In cases of posterior instability, causative factors are reported to be excessive glenoid component retroversion, humeral component retroversion, glenoid component loosening, continued static posterior subluxation, a smaller glenoid component, and soft tissue imbalances or insufficiency including rotator cuff tear. [1],[5],[6] Preoperative factors include posterior glenoid wear, bone loss, a biconcave glenoid, and static posterior subluxation. [4],[7] A detailed understanding of the underlying etiology is essential to determine the appropriate treatment.
At the time of the arthroplasty, methods to prevent postoperative instability include eccentric reaming, posterior bone grafting, using an augmented glenoid component, and addressing posterior capsular laxity or rotator cuff pathology. [2] A study has demonstrated that increasing the humeral component anteversion does not provide improved stability in the setting of persistent glenoid retroversion. [8] Patients with postoperative instability of the prosthesis despite the use of the aforementioned methods present a difficult clinical challenge. Nonoperative measures may not be successful in alleviating the symptoms. In evaluating a patient with instability, the etiology must be determined through a clinical exam and appropriate imaging. The position of the components, loosening, static posterior subluxation and soft tissue stabilizers are all assessed. Based on the underlying cause of the instability, operative options include revision of one or both of the components, soft tissue plication or repair, bone grafting procedures with or without component revision, and bone block type procedures. Understanding the reasons for posterior instability is critical to determining the treatment options [Figure 5]. In many cases, more than one factor can contribute to posterior instability. Current surgical treatment has demonstrated only fair results in restoring stability with inconsistent reproducibility. [2],[9]
In the case presented here, the patient was found to have clinically symptomatic posterior instability after a primary TSA with persistent subluxation and glenoid retroversion. An open revision surgery was considered, but secondary to the reported mixed results of these procedures a novel, less invasive surgery was undertaken. This included an arthroscopic posterior bone block augmentation of the glenoid with iliac crest autograft. While this procedure has recently been published for posterior instability, there are no reports to our knowledge of this technique in the setting of a TSA. [10] Endres and Warner described two patients with anterior instability after TSA successfully treated with an open Latarjet procedure. [11]
The arthroscopic bone block procedure offers a number of advantages in this setting. It can be performed through a minimally invasive approach, and excellent visualization is achieved to allow proper positioning of the graft. The graft helps to re-center the humeral head by increasing the surface area of the glenoid, thus making a dislocation more difficult. In addition, the graft is placed flush against the glenoid component, which may help stabilize this and prevent loosening from edge loading.
Conclusion | | ![Top](/ServeContent?url=http%3A%2F%2Fwww.internationalshoulderjournal.org%2Fimages%2Farrow_top.gif) |
This case report describes the management of symptomatic posterior shoulder instability following TSA and also reports a novel technique. To our knowledge, this is the first description of a posterior, arthroscopic iliac crest bone block grafting procedure in this setting. The procedure represents a treatment option for posterior instability in the setting of a stable glenoid prosthesis following TSA.
References | | ![Top](/ServeContent?url=http%3A%2F%2Fwww.internationalshoulderjournal.org%2Fimages%2Farrow_top.gif) |
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4. | Walch G, Moraga C, Young A, Castellanos-Rosas J. Results of anatomic nonconstrained prosthesis in primary osteoarthritis with biconcave glenoid. J Shoulder Elbow Surg 2012;21:1526-33. |
5. | Jahnke AH Jr, Hawkins RJ. Instability after shoulder arthroplasty: Causative factors and treatment options. Semin Arthroplasty 1995;6:289-6. |
6. | Tammachote N, Sperling JW, Berglund LJ, Steinmann SP, Cofield RH, An KN. The effect of glenoid component size on the stability of total shoulder arthroplasty. J Shoulder Elbow Surg 2007;16:S102-6. |
7. | Iannotti JP, Norris TR. Influence of preoperative factors on outcome of shoulder arthroplasty for glenohumeral osteoarthritis. J Bone Joint Surg Am 2003;85-A:251-8. |
8. | Spencer EE Jr, Valdevit A, Kambic H, Brems JJ, Iannotti JP. The effect of humeral component anteversion on shoulder stability with glenoid component retroversion. J Bone Joint Surg Am 2005;87:808-14. |
9. | Iannotti JP, Greeson C, Downing D, Sabesan V, Bryan JA. Effect of glenoid deformity on glenoid component placement in primary shoulder arthroplasty. J Shoulder Elbow Surg 2012;21:48-55. |
10. | Lafosse L, Franceschi G, Kordasiewicz B, Andrews WJ, Schwartz D. Arthroscopic posterior bone block: Surgical technique. Musculoskelet Surg 2012;96:205-12. |
11. | Endres NK, Warner JJ. Anterior instability after total shoulder replacement: Salvage with modified Latarjet procedure. A report of 2 cases. J Shoulder Elbow Surg 2010;19:e1-5. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
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