Background: Capsular laxity is the main pathology in patients with multidirectional instability, and thermal shrinkage has been commonly employed to treat this condition. The objective of this study was to evaluate thermal capsular shrinkage as a treatment of multidirectional instability of the shoulder.

Methods: Nineteen consecutive patients with multidirectional instability were treated with thermal shrinkage. Fifteen patients had involuntary instability, and four had voluntary instability. The predominant direction of the instability was anteroinferior in ten patients and posterior in five; four patients had instability in multiple directions. Patients were followed for a minimum of two years or until surgical failure and recurrence of symptoms. Postoperatively, the patients wore a sling for three weeks, and they were evaluated regularly at three, six, and twelve months. The Western Ontario Shoulder Instability Index as well as subjective and objective evaluations of the patient's function, range of motion, pain, and instability were used as clinical outcome measures.

Results: Nine patients had recurrence of the instability at an average of nine months (range, seven to fourteen months) following the surgical procedure. Four patients had sensory dysesthesias in the axillary nerve distribution, and one of them had deltoid weakness. All neurological symptoms resolved within nine months. The surgical procedure failed in the five patients with predominantly posterior instability. It failed in only two of the ten patients with predominantly anteroinferior instability, and overall this group had objective improvement.

Conclusions: Thermal capsular shrinkage used to treat multidirectional instability had a substantial failure rate with associated postoperative complications, including recurrence of instability (nine of the nineteen patients), stiffness (five patients), and neurological symptoms (four patients).

Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.