Good afternoon. I'm Dr. Christopher Uggen with Borges Horse Feeding Clinic in Kalamazoo, Michigan, as well as Western Michigan University School of Medicine. Today we're discussing the Mumford procedure, how much resection is enough, and what are some technical hurdles for success. My relevant disclosures include consulting with a striker instrument division and navigation, as well as owning striker stock. First, looking at the outcomes and indications for the arthroscopic Mumford procedure, looking at the ABOS web-based longitudinal assessment knowledge sources from 2020. An article was selected from HASM 2015, showing no difference in AC joint tenderness, AAS scores, ASES, or constant scores when arthroscopic distal palpable resections were combined with arthroscopic rotator cuff repairs. This would suggest that it may be unnecessary to perform distal palpable resections concurrently with rotator cuff repairs, but I would suggest that the current outcomes measuring systems are not sensitive enough to pick up the importance of concurrent procedures with a rotator cuff tear as such a dominant pain generator. Carrying this thought even further, there may be a role for arthroscopic distal palpable resections in combination with rotator cuff repair, even if there is symptomatic pre-op, particularly if there is inferior hypertrophy. Looking at the study from 2011, 83 patients with concurrent rotator cuff tears and hypertrophic AC joint arthritis were randomized into rotator cuff repair alone or rotator cuff repair with arthroscopic distal palpable resection, and they showed that although the UCLA and ASES scores were lower at the 6-week and 12-week mark in the Mumford group, these scores were higher at the 2-year mark. I routinely add arthroscopic to my rotator cuff repairs when there's hypertrophic inferior spurring, and my preferences for the arthroscopic procedure, supported by systematic reviews showing that the arthroscopic procedure leads to faster return to activities while attaining similar long-term outcomes compared to the open procedures. My current indications for performing an arthroscopic lung procedure include stable, symptomatic ACR arthritis that's failed on an open treatment, as well as asymptomatic hypertrophic ACR arthritis with inferior spurring in the presence of a rotator cuff repair. During this procedure, we choose for a resection of approximately one centimeter from the disc laval, as well as several millimeters from the medial endocromium. A minimum of five millimeters of disc laval needs to be resected to prevent one-on-one contact based on a biomechanic study. And then, at the completion of the procedure, you must be able to visualize the entire disc laval circumference. Anatomic studies show that 10 millimeters of disc laval resection removes approximately 8% of the trapezoid or clavicular ligament. In other clinical studies, postoperative pain is much greater in patients with more than one centimeter of disc laval resection. So, 8 to 10 millimeters seems to be the ideal amount. Moving on, technical pearls for success. Number one, your anterior working portal must be coplanar with the AC joint for ease of access. If your anterior working portal is too far off, go ahead and make another skin incision in order to get coplanar with this joint. Good visualization in the subacromial space is critical when performing this procedure arthroscopically. I usually carry an aggressive resection all the way back to the scapular spine. Also, when performing a subacromial compression, the acromion resection should be carried all the way medial to the AC joint. During the arthroscopic disc top, one must resect the entire anterior AC joint capsule from inferior to the 12 o'clock position in order to get the shaver to the posterior portion of the clavicle. Sometimes, one starts with the lower portion of this capsule, then resects bone and goes back to resect the remainder of the anterior capsule. Also, the more oblique the AC joint is oriented, the more medial aspect of the acromion that needs to be resected. This serves two purposes. It reduces the impingement. After the completion of the case, it also allows better visualization into the superior aspect of the joint. Finally, one must preserve the posterior superior capsule of the AC joint during the resection in order to preserve the A to P stability. At the completion of the procedure, one should easily be able to see the entire circumference of the discalclical, and one should be able to fit the arthroscopic cannula from inferior to superior and from front to back within the reception space. My final recommendation is to consider using an egg burr instead of a barrel burr for the subacromial decompression and distal palpebral resection. The egg burr allows one to move more easily from lateral to medial during the acromial resection and from anterior to posterior during the distal palpebral resection without interference with the skirt of the shaver. To conclusion, look for the inferior AC joint hypertrophy on your imaging, line x-rays as well as MRI. Look for the effacement of the subarticular fat above the rotator cuff. Also be aware of the AC joint liquidity as the more orally the AC joint is oriented, the more resection of the medial edge of the acromion is indicated. The ideal resection should be 8-10 mm including the portion of the medial acromion. Also preserve the posterior superior capsule in order to avoid AC joint A-P instability. Thank you.

Mumford procedure

rotator cuff repair

arthroscopic distal resection

technical recommendations

AC joint hypertrophy