ABSTRACTS

throscopic repairs had full recovery of motion; open repairs lacked an average of 9” external rotation. Both techniques offer good results. Arthroscopic techniques seem best suited to patients who require full external rotation or prefer a less painful proce- dure; open repair is best suited for those patients where recurrence is less acceptable. Contact ath- letes and patients not willing to comply with immo- bilization are not suitable for arthroscopic repair.

Innervation of the Human Knee Joint by Substance P Fibers. Edward M. Wojtys, Douglas Beaman, Roy A. Glover, and David Janda. Ann Arbor, Michigan, U.S.A.

Anterior knee pain is a frequent musculoskeletal complaint affecting all ages, both sexes, and ath- letes and nonathletes alike. Numerous theories have been proposed regarding its etiology, includ- ing patellar malalignment , quadriceps insufficiency, patelIar subluxation, quadriceps muscle tightness, and chondral defects. However, the mechanism by which these factors produce this pain is not clear. To better understand painful syndromes about the knee, the authors investigated the presence of no- ciceptive nerve fibers in 11 human knee specimens, eight from patients with degenerative patellofemor- al disease and three from normal subjects. Immu- nohistochemical techniques using monoclonal anti- body to substance P were employed. (Substance P is a neurotransmitter known to be important in sen- sory nerve fibers responsible for pain transmission. It is also a powerful inflammatory agent capable of producing vasodilatation and joint effusion.) Sub- stance P fibers were isolated in the retinaculum, fat pad, periosteum, and subchondral plate of patellae affected with degenerative disease. In the degener- ative specimens, substance P fibers could be seen at the bone hyaline cartilage interface; however, these fibers were not present at the hyaline cartilage sub- chondral plate interface of normal specimens.

This study demonstrates that selective tracing of nociceptive pain fibers is possible around the knee in both soft tissue and, in some circumstances, bone. There is some evidence that the pattern of innervation changes with degenerative disease. We also postulate that certain orthopedic procedures such as lateral retinacular release and fat pad resec- tion may be denervating procedures, possibly pro-

ducing their beneficial effects by decreasing the concentration of substance P released into affected knee joints.

Anatomy and Diagnostic Arthroscopy of the Sub- acromial Bursa. Eugene M. Wolf. San Francisco, California, U.S.A.

The objective was to study the gross and arthro- scopic anatomy of the subacromial space. An ana- tomical and a clinical study of the subacromial bursa was undertaken to provide orientation and guidelines in diagnostic arthroscopy of the subacro- mial space. This study attempts to clarify some con- cepts that have developed through our early expe- rience in this area.

The subacromial bursae and glenohumeral joints of 15 fresh cadaver shoulder specimens were exam- ined arthroscopically. Lateral, posterior, and ante- rior arthroscopic portals were used to examine the extent of the bursa. AlI intrabursal structures and their relationships were identified. The arthroscopy was then followed by a detailed anatomical dissec- tion. In the clinical study, 23 patients underwent arthroscopy of the subacromial bursa and gleno- humeral joint, for diagnosis and treatment of im- pingement .

A technique of diagnostic bursoscopy was devel- oped to consistently enter the bursa and observe its contents without using a motorized shaver. The lim- its and contents of the space and the medial, lateral, and anterior sulci were defined. The rotator cuff, the coracoacromial ligament, the subdeltoid fascia, and the inferior surface of the acromion were uni- formly identified and pathologic findings were noted.

This study defines the anatomy of the subacro- mial space and demonstrates that diagnostic sub- acromial bursoscopy, used in conjunction with gle- nohumeral arthroscopy, is an important adjunct in the diagnosis and treatment of impingement. This technique consistently permits a traumatic entry into the subacromial space and the demonstration of intrabursal impingement lesions prior to the use of a motorized shaver. These subacromial lesions can be the only lesions present in impingement syn- dromes and should be identified prior to proceeding with a subacromial decompression.

Arthroscopy, Vol. 6, No. 2, 1990