TO THE EDITOR:
"Revision Total Shoulder Arthroplasty for the Treatment of Glenoid Arthrosis" by Sperling and Cofield (80-A: 860—867, June 1998) was an excellent and informative review of the authors' experience with glenoid resurfacing in patients who had painful glenoid arthrosis after hemiarthroplasty of the shoulder. Their findings regarding pain relief and patient satisfaction support the performance of revision total shoulder arthroplasty in appropriately selected patients.
The ranges of postoperative abduction, however, were greater than those that I have seen in my clinical practice. I wonder if I am measuring abduction in the same manner. When I measure abduction, my reference point is the long axis of the thoracic spine. The patient is disrobed to the waist and is viewed from behind with both arms simultaneously abducted in the coronal plane. The simultaneous abduction of the arms and the dorsal view of the patient prevent motion of the spine on the pelvis from being misinterpreted as humeral abduction. In addition, maintaining the arms in the coronal plane prevents any contribution of forward flexion or adduction from being misread as abduction.
Andrew P. Gutow, M.D.: Department of Orthopaedics, Emory University School of Medicine, 20 Linden Avenue, Suite 3703, Atlanta, Georgia 30308
Dr. Sperling and Dr. Cofield reply:
Apropos of Dr. Gutow's inquiry, we too were surprisingly pleased with the range of movement achieved after the revision procedure. In retrospect, many factors contributed to this good motion. Many of the patients were younger than those who typically have a shoulder arthroplasty. Three of the ten patients who had normal or nearly normal postoperative movement had had excellent movement before the revision, all ten had a good rotator cuff, none had severe scarring as a result of high-velocity trauma or previous operative treatment, and none had an osseous deformity or substantial bone loss.
Recent improvements in operative technique have played an important role in increasing the range of motion that can be achieved after shoulder arthroplasty. When we perform this procedure, we meticulously release areas of scarring in each tissue layer. During a revision procedure, we routinely release the inferior aspect of the shoulder capsule from the humerus. The implant that we use has a somewhat high head-shaft angle that allows the surgeon to avoid filling the inferomedial aspect of the glenohumeral joint with metal; the metaphysis in that area is also trimmed. Furthermore, the implant is now available in many sizes, which allows the surgeon to make more precise judgments about the range of motion and stability. During the operation, the range of motion is carefully assessed; if there is any deficiency, additional releases are performed or the size of the implant is adjusted. Importantly, the intraoperative determination of stability and the range of motion makes it possible to tailor physiotherapy more precisely. While none of these measures in and of themselves may be overly dramatic, all of them together have greatly improved motion after shoulder arthroplasty and, no doubt, contributed substantially to the motion achieved in a number of our patients after the revision procedure.
Of note, we measured preoperative and postoperative abduction much as Dr. Gutow described. The patient was in the sitting position, and the position of the arm was assessed relative to the thoracic spine.
We thank Dr. Gutow for his interesting and insightful comment regarding the range of motion. We also noticed this finding and considered it a great deal when we analyzed the data in our study. More importantly, we have subsequently attempted to recreate this excellent motion in all patients, regardless of whether they are having primary or revision shoulder arthroplasty.
John W. Sperling, M.D.; Robert H. Cofield, M.D.: Department of Orthopedics, Mayo Clinic, 200 First Street S.W., Rochester, Minnesota 55905