Commentary & Perspective

Commentary & Perspective on
"Thermal Capsular Shrinkage for Treatment of Multidirectional Instability of the Shoulder"
by Anthony Miniaci, MD, FRCSC, and Julie McBirnie, MD, FRCS(Orth)

Commentary & Perspective by
Evan L. Flatow, MD*,
Department of Orthopaedic Surgery, Mt. Sinai Medical Center, New York, NY

Glenohumeral instability has been recognized as a clinical problem since antiquity, with many described treatments. Modern surgical techniques have been directed at correction of underlying pathologies, such as labral detachment, glenoid fracture or bone loss, and capsular laxity^1,2. Neer and Foster described multidirectional instability, in which capsular laxity is the predominant pathology, and recommended a technique of open global capsular tightening for the treatment of patients for whom nonoperative management had failed^3,4.

Early arthroscopic techniques of shoulder stabilization proved more effective for the repair of labral avulsions than for the reduction of capsular laxity and were often reserved for traumatic recurrent unidirectional dislocations^5,6. Techniques for arthroscopic suture capsulorrhaphy were developed for multidirectional instability, but these techniques were associated with a steep learning curve⁷. In contrast, radiofrequency thermal capsular shrinkage is a simple procedure that can be performed without much required training. Thus, thermal capsulorrhaphy was widely adopted at a time in which a variety of basic-science investigations were being performed but, unfortunately, before adequate clinical trials had been reported in the peer-reviewed literature.

The current study is an excellent contribution to our understanding of the value of thermal capsular shrinkage. Nineteen consecutive patients with symptomatic multidirectional instability treated with thermal capsulorrhaphy were followed for a minimum of two years or until failure. While many reports in the literature are imprecise in the criteria for the diagnosis of multidirectional instability, this study excluded asymptomatic laxity and had as inclusion criteria symptomatic, unwanted translations anteriorly, inferiorly, and posteriorly. Despite the fact that the thermal technique was used as was recommended at the time, at follow-up, nine patients (47%) had recurrent instability, five (26%) had stiffness, and four (21%) had axillary nerve injuries. While it is possible that the more recently recommended "stripe" technique, in which strips of normal tissue are left untreated between rows of thermally shrunk capsule, might work better, this is as yet unproven.

The highest rate of failure was in patients for whom the predominant direction of instability was posterior. While all patients were immobilized in a sling postoperatively, it is well established that immobilization after open repairs should be in neutral rotation in a brace to prevent stretching out of the posterior capsule⁸. Treatment failed in four patients who could reproduce the instability positionally. Interestingly, this propensity has not been a contraindication with open repairs, whereas the ability to hold the shoulder out of joint with muscular contraction has been associated with a high risk for failure of repair. The conclusions to be drawn from this small group remain unclear.

Since the occurrence of both stiffness and recurrent instability were unpredictable, it is unlikely that these complications could be avoided simply by adjusting the length of postoperative immobilization. Most disturbing was the difficulty of revision, including the need for allograft reconstruction in one patient. In conclusion, this study does not support the use of radiofrequency thermal capsular shrinkage for multidirectional shoulder instability. More studies of this type should have been performed before this technology was widely adopted.

*The author did not receive grants or outside funding in support of his research or preparation of this manuscript. He did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.

References

1. Flatow EL, Warner JJP. Instability of the shoulder: complex problems and failed repairs. Part I. Relevant biomechanics, multidirectional instability, and severe loss of glenoid and humeral bone. J Bone Joint Surg Am. 1998;80:122-40.
2. Levine WN, Flatow EL. The pathophysiology of shoulder instability. Am J Sports Med. 2000;28:910-7.
3. Neer CS, Foster CR. Inferior capsular shift for involuntary inferior and multidirectional instability of the shoulder: a preliminary report. J Bone Joint Surg Am. 1980;62:897-908.
4. Pollock RG, Owens JM, Flatow EL, Bigliani LU. Operative results of the inferior capsular shift procedure for multidirectional instability of the shoulder. J Bone Joint Surg Am. 2000;82:919-28.
5. Flatow EL, Miniaci A, Evans PJ, Simonian PT, Warren RF. Instability of the shoulder: complex problems and failed repairs. Part II. Failed repairs. J Bone Joint Surg Am. 1998;80:284-98.
6. Levine WN, Arroyo JS, Pollock RG, Flatow EL, Bigliani LU. Open revision stabilization surgery for recurrent anterior glenohumeral instability. Am J Sports Med. 2000;28:156-60.
7. McIntyre LF, Caspari RB, Savoie FH 3rd. The arthroscopic treatment of multidirectional shoulder instability: two-year results of a multiple suture technique. Arthroscopy. 1997;13:418-25.
8. Bigliani LU, Pollock RG, McIlveen SJ, Endrizzi DP, Flatow EL. Shift of the posteroinferior aspect of the capsule for recurrent posterior glenohumeral instability. J Bone Joint Surg Am. 1995;77:1011-20.