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Novel Arthroscopic Surgery Promising for Treatment of Scapulothoracic Abnormal Motion

Key findings

  • This retrospective study of prospectively collected data involved 31 patients with chronic scapulothoracic abnormal motion who had underlying contributing factors of both pectoralis minor hyperactivity and serratus anterior hypoactivity
  • A novel management approach, the combination of arthroscopic pectoralis minor release and scapulopexy, resulted in substantial improvements in pain, motion and function in 81% of patients over an average follow-up of 23 months
  • One patient sustained a traumatic rupture of the scapulopexy and required revision
  • Four patients (13%) had minimal postoperative improvement and experienced recurrence within three months postoperatively
  • The novel approach is also expected to be effective for patients whose scapulothoracic abnormal motion has no known underlying cause

Scapulothoracic abnormal motion (STAM) is a group of scapular conditions, including scapular dyskinesis and medial or lateral scapular winging, that can lead to chronic pain, weakness, limited motion, and deformity. Dysfunction of the serratus anterior, from either long thoracic nerve palsy or trauma, is recognized to be a potential contributing factor. Some studies have pointed to pectoralis minor tightness or hyperactivity as another possible contributor.

Scapulopexy and, separately, arthroscopy for pectoralis minor release have been studied for the treatment of STAM. Since 2017, Bassem T. Elhassan, MD, co-chief of the Shoulder Service in the Massachusetts General Hospital Department of Orthopaedic Surgery, has been combining those procedures in selected patients.

In the Journal of Shoulder and Elbow Surgery, Dr. Elhassan, Matthew J. Best, MD, a sports medicine fellow in the department, and colleagues report on 31 consecutive patients who underwent the novel surgical approach, most of whom experienced improvements in pain, range of motion and function.


When the pectoralis minor is hyperactive, the muscle fibers of the serratus anterior may elongate and thus not effectively activate to stabilize the distal tip of the scapula against the chest wall. Arthroscopic release of the pectoralis minor in combination with a scapulopexy may allow the serratus anterior muscle fibers to shorten over time, permitting patients to learn how to appropriately activate the muscle and correct their STAM.

The novel surgical technique, discussed in detail in the article with accompanying photographs, addresses both hyperactivity of the pectoralis minor and hypoactivity of the serratus anterior by fixing the scapula to the chest wall.

Description of the Cohort

The authors retrospectively identified the 31 patients from a prospective registry maintained at Mass General. All had persistent pain and continued abnormal scapular motion despite conservative management for at least six months.

The patients were diagnosed with pectoralis minor hyperactivity and serratus anterior hypoactivity when they exhibited excessive anterior tilt of the affected shoulder compared with the contralateral side. The article explains two tests for determining whether STAM is due to pectoralis minor hyperactivity and not serratus dysfunction.

The average age at the time of surgery was 24 (range, 14–44) and 80% of patients were female. 13 also had a diagnosis of recurrent posterior instability. The surgical approach was at the discretion of Dr. Best, who treats a high volume of patients with STAM.


At the time the paper was written, the average postoperative follow-up was 23 months (range, 15–39 months). 81% of patients reported substantial improvement:

  • Pain score—an average of 6 preoperatively vs. 2 at the latest follow-up
  • Shoulder subjective value—30% vs. 75%
  • Constant Shoulder Score—49 vs. 79 (P<0.01)
  • Flexion range of motion—100° vs. 140°

All 13 patients with posterior instability reported subjective improvement; no objective data were collected.

One patient had a traumatic rupture of the tendon allograft used for the scapulopexy, seven weeks postoperatively, and underwent revision scapulopexy. Four patients (13%) had minimal improvement after surgery and experienced recurrence within three months postoperatively.

Guidance for Orthopedic Surgeons

This study did not allow for the assessment of long-term outcomes, but the favorable results can inform the development of a new treatment protocol for patients with STAM.

For many patients with STAM, there is no known underlying cause, such as paralysis or proven nerve injury. Hypoactivity of the serratus and hyperactivity of the pectoralis minor may contribute to scapular dysfunction in these patients as well, and this study suggests the novel procedure would provide functional improvement.

of patients with chronic STAM due to pectoralis minor hyperactivity and serratus anterior hypoactivity responded well to the combination of scapulopexy and arthroscopic pectoralis minor release

of patients with chronic STAM due to pectoralis minor hyperactivity and serratus anterior hypoactivity had minimal improvement after the combination of scapulopexy and arthroscopic pectoralis minor release

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Related topics


Bassem Elhassan, MD, orthopaedics professor at Harvard Medical School, co-chief of the Shoulder Service and program director of the Shoulder Surgery Fellowship at Massachusetts General Hospital, has developed techniques for achieving excellent outcomes in rotator cuff tears that were previously considered irreparable.


Matthew J. Best, MD, Sports Medicine fellow, and Scott Martin, MD, director of the Joint Preservation Service in the Department of Orthopaedics at Massachusetts General Hospital, and colleagues examined racial differences in total shoulder arthroplasty (TSA) and reverse TSA data over five year period (2012-2017).