Merrick J. Wetzler

Revision anterior cruciate ligamentreconstruction

Abstract Anterior cruciate ligament (ACL) reconstruction has gained, wide acceptance as the treatment of choice for thefunctionally unstable ACL-deficient knee and is now performed on about a half million individuals, per year. The documented long-term good or excellent result rates for functional stability, relief of symptoms, and return to activity for intra-articular ACL reconstructions is approximately 75% to 95%. This leaves a substantial group of patients with an unsatisfactory result secondary to a variety of reasons. Review of the literature reveals that recurrent instability and graft failure are responsible for unsatisfactory results in as high as 8% of these patients. In this article, the factors responsible for graft failure and recurrent instability are discussed. In addition, the planning and difficulties that the orthopedic surgeon must address before, during, and after the procedure, are also reviewed.

Failure properties of suture anchors in the glenoid and the effects of cortical thickness

The ultimate pullout strength and fatigue properties of a screw-design suture anchor implanted in the anterior glenoid rim were investigated and compared with results from a nonscrew-design suture anchor. Twenty-two cadaveric glenoids were harvested and one to two anchors were implanted in the superior and inferior quadrants. Fifty-seven Statak 3.5 anchors (Zimmer, Warsaw, IN) were tested and compared with results obtained in a previous study on 50 Mitek GII anchors (Mitek Products, Inc, Westwood, MA). The specimens were mounted on an Instron fatigue testing machine (Instron Corp, Canton, MA) and cycled between preselected minimum and maximum loads until pullout. The Mitek GII maintained a higher pullout strength than the Statak 3.5 after cyclic loading. Cortical thickness at the implantation sites was measured, and found to decrease monotonically from superior to inferior positions. The ultimate pullout strength, and subsequently the fatigue life, of both types of suture anchors depended directly on cortical thickness. The significantly lower performance of both anchors when placed inferiorly emphasizes the importance of correct anchor selection, number, and placement in this region. All anchors settled during the first 10 to 100 cycles, resulting in partial exposure of the implant. Intraoperative cycling of the anchors before suture tying may be necessary to achieve complete settling and prevent subsequent loss of coaptation between capsule and glenoid. The study shows that for the anchors to last 1,000 cycles or more, less than 50% of the theoretical ultimate pullout strength should be applied cyclically. With aggressive early rehabilitation exercises, this significant decrease in fixation strength could shift reconstruction failure from suture breakage or soft tissue tearing to anchor pullout.

Fatigue properties of suture anchors in anterior shoulder reconstructions: Mitek GII

Suture anchors have simplified anterior capsule labral reconstruction. During rehabilitation the shoulder goes through many repetitions of range of motion exercises. These exercises will repetitively submaximally load the anchor and in theory should reduce the pullout strength of the suture anchor. No published reports exist on the fatigue strengths and properties of one of the most commonly used anchors: Mitek GII suture anchors. Fifty trials of cyclic submaximal load were done on 22 cadaveric glenoids with an average age of 66.8 years (range, 40 to 90 years). At two to three different sites on the same specimen, the anchors were inserted according to manufacturers specifications. The anchors were tested to failure on a Instron 1331 servohydraulic mechanical testing system at 2 Hertz sinusoidal loading pattern using steel sutures and a predetermined load. There were 22 (44%) tests performed in the superior quadrant and 28 (56%) tests in the inferior quadrant. All anchors pulled out, and no wires broke. There were statistically significant differences between the superior and inferior portion of the glenoid with regard to number of cycles to failure at a given maximum load. The anchors underwent an average of 6,220 cycles before pullout at an average load of 162 N (SD = 73 N). In the superior quadrant, the average ultimate pullout strength was 237 N (SD = 42 N), whereas in the inferior quadrant the average ultimate pullout strength was 126 N (SD = 36 N). Hence, the ultimate pullout strength of the Mitek GII anchor was significantly higher (P < .002) in the superior quadrant than in the inferior quadrant. Using a least squares regression analysis, it was possible to predict the fatigue life of the superiorly and inferiorly placed suture anchors over a wide range of cycles. The R-squared values for trendlines showed good reliability (superior R2 = 0.55; inferior R2 = 0.28). The fatigue life curves for the two different quadrants were normalized using the ultimate pullout strength. This new, universal curve predicts the fatigue life of the Mitek GII anchor as a percentage of the ultimate pullout strength for any selected location. For a clinically relevant number of cycles, no more than approximately 40% to 50% of the ultimate pullout strength of the suture anchor can be cyclically applied to the anchor to guarantee a life for the duration of rehabilitation. For the entire system, the inferiorly placed anchors dictate the amount of cyclically applied load the system can experience without failing, and rehabilitation should be adjusted accordingly.

Related Research and Arthroscopy: Increasing the Breadth of Arthroscopy and Arthroscopy Techniques

An editorial goal is to increase the breadth of Arthroscopy and Arthroscopy Techniques. Our readers are more than arthroscopic surgeons and scientists. Rather, the health care providers and scientists who read our journals are, first and foremost, physicians, allied health practitioners, and academic intellectuals whose interests include improving individual and public health and welfare across a wide spectrum of scholarly topics. By reaching a broader audience, we hope to expand our contribution to arthroscopic and related surgery and continue to develop the potential of our subspecialty.

Editorial Commentary: Doc, Can You Inject Stem Cells in My Knee?

Stem cell therapy is one of the most promising treatments to restore and repair damaged articulate cartilage. Koh et al. present in this issue their study on the treatment of articulate cartilage defects with adipose derived stem cell. We believe that it is a matter of time to when stem cells will become cost effective and commercially available for the treatment of articulate cartilage injuries.

Editorial Commentary: Google It!—Reliability of Medical Information Found on the Internet

Patients use Google or other search engines to obtain information on various medical problems. This information is not always reliable, and physicians should direct patients to Web sites that are validated and reliable.

Injuries in the Chinese Arena Football League: American Versus Chinese Players

Background: Arena football is an indoor version of American football played in indoor arenas on a smaller field with 8 players per team. Only 1 study has evaluated injury rates in arena football, and no study had compared 2 distinct cohorts of players. Purpose/Hypothesis: The purpose of this study was to evaluate and compare injury rates in American versus Chinese athletes in the Chinese Arena Football League. Our hypothesis was that the rate of significant injuries (≥7 days of time lost from play) would be statistically significantly higher in Chinese athletes. Study Design: Cohort study; Level of evidence, 2. Methods: Each of the 6 teams included in this study comprised 11 American and 11 Chinese athletes, for a total of 132 included athletes (66 Chinese, 66 American). All players stayed in the same hotel, trained and played in the same facilities, and were covered by the same medical staff. A total of 18 games were played consecutively in 6 cities from October 1 to November 6, 2016. At least 4 Chinese players had to be on the field for each team at all times during game play. Results: American athletes were significantly older, taller, and heavier than Chinese athletes. The total exposure was 759 athlete-hours, and there were 80 reported injuries, with 74 (92.5%) occurring during games (overall injury rate, 105.4 injuries per 1000 athlete-hours). For American athletes, the exposure was 387 athlete-hours with 38 injuries observed, and the injury rate was 98.2 injuries per 1000 athlete-hours. For Chinese athletes, the exposure was 372 athlete-hours with 42 injuries observed, and the injury rate was 112.9 injuries per 1000 athlete-hours. There was no statistically significant difference in exposure or overall injury rate between American and Chinese athletes. The rate of significant injuries was 30.3 per 1000 athlete-hours; there were 17 such injuries in Chinese athletes compared with 6 such injuries for American athletes. The rate of significant injuries was 45.7 (Chinese) and 15.5 (American) injuries per 1000 athlete-hours, and the relative risk for Chinese versus American athletes for significant injuries was 3.0 (95% CI, 1.2-7.8; P = .019) . Binary logistic regression models were utilized to analyze whether the baseline variables (height, weight, body mass index, age, years of experience, and nationality) were potential predictors for an injury, and only years of experience (odds ratio, 1.147 [95% CI, 1.034-1.271]; P = .009) was found to be associated with severe injuries (>21 days of time loss). Conclusion: The overall risk of injuries was similar between Chinese and American athletes, but Chinese athletes showed statistically higher rates of significant injuries than their American counterparts. Years of experience was the only factor that was associated with severe injuries. As professional sports become more global, medical personnel must take into account the distinct differences and levels of experience between the national and international professional athletes. The results of this study will be used to make recommendations to develop preventive training measures, including techniques to improve tackling.

Editorial Commentary: Don't Forgot the Hip in Swimmers and Multisport Athletes

Swimming results in significant and repetitive stress on the hip as well as other joints, and hip pain in swimmers should not be ignored. Stretching and strengthening are the mainstays of injury prevention, and recent literature supports that when indicated, femoroacetabular impingement surgical treatment in swimmers results in excellent outcomes including return to sport and frequently at a level of performance superior to pre-injury status.

Editorial Commentary: Is the Cure Worse Than the Disease? Harvesting Autologous Osteochondral Transfer Plugs for Treatment of Lesions of the Elbow

For autologous osteochondral transfer procedures for osteochondritis dessicans of the elbow, surgeons usually use the knee or ribs as donor sites. This procedure is not without donor site complications. Finding local donor sites is important to reducing the overall morbidity of this procedure.

Editorial Commentary: When a Tie Is Still a Win: Systematic Reviews Showing No Difference Between Treatments May Not Be Generalizable to Individual Patients

When a systematic review finds no difference between treatment options for a particular disorder, this could mean more than you think. Individual patients requiring shoulder Bankart repair are unique with respect to their demands and expectations and pathology. Surgeons should combine published principles with understanding of their own skills and their specific patient to optimize a treatment outcome.