Multidirectional Instability (Loose Shoulder)

Abstract

Multidirectional instability (MDI) was a new concept of shoulder disease, first reported by Hisao Endo in 1971 [1]. He reported this disease using the German term “sog. Schulterschlottergelenk,” which means the so-called loose shoulder. His patients had no history of trauma, had hyperlaxity of the shoulder, and showed inferior dislocation or subluxation in the hanging arm position at rest. In addition to dull pain at rest, they often complained motion pain of the shoulder and a sense of fatigue around the shoulder girdle. Due to pain, it was difficult for them to elevate the arm. He performed motion analysis of 8 patients and found that upward rotation of the scapula was disturbed during the early phase of arm elevation, which made them difficult to elevate the arm. By manually supporting the scapula to rotate upward, inferior instability disappeared, and they were able to fully elevate the arm. He thought this scapular dyskinesis was the essential pathophysiology of this disease and performed the pectoralis major transfer to the inferior angle of the scapula to promote upward rotation of the scapula in one patient after failed Bankart repair. Four months after the surgery, this patient showed no inferior subluxation at rest and could fully elevate the arm without pain or difficulty. This report was published in the Central Japan Journal of Orthopaedic Surgery & Traumatology in 1971. It was a short report, but I was very impressed by the logical and organized contents of this paper. I still recollect a vivid sensation of excitement when I first read this paper. He searched for the why (pathophysiology) of this disease, performed a surgery to correct it, and reported the outcome of his surgery. This was one of the best articles I have ever encountered. Most unfortunately, however, this paper was written in Japanese. No one outside of Japan had paid attention to this paper. In 1976, Charles Neer was invited to the third Annual Meeting of the Japan Shoulder Society and had a chance to listen to Endo’s presentation for the first time. Neer seemed to be very interested in and stimulated by Endo’s presentation. Four years later, he published his famous paper about MDI in JBJS-Am in 1980. This was exactly what Endo reported in 1971. In Neer’s paper, he referred to Endo’s presentation at JSS meeting, but not the paper in 1971. Therefore, most people who read his paper believed that Neer was the first to report the concept of MDI. This was the reason why we wanted to introduce Endo’s work to the world. I sent his original article with English translation to William J. Mallon, Editor of JSES, saying as follows. “There are many excellent papers in the world but most of them are embedded in its own country because it is written in its own language. People have no access to them unless they were written in English. As the top journal in this field, I think JSES should have a role to introduce these excellent papers to the world as ‘Classic Articles’.” Bill Mallon and Jonathan B. Ticker, Editor of compilation of history of American Shoulder and Elbow Surgeons, both agreed to publish this paper. In 2012, Endo’s paper was introduced to the world as the first “Classic Article” in JSES [2]. Our dream has come true. Forty-one years have passed since his original publication. We feel sorry that Dr. Endo passed away just 1 year before his work appeared in JSES. We believe that his contribution would be remembered by all the shoulder surgeons who read his paper.