Arthroscopic SLAP IIb Repair Using Knot-Tying Versus Knotless Suture Anchors: Is There a Difference?

Although KJOC (66.1 vs 65.6 P = .61) and ASES (86.3 vs 85.3 P = .79) scores were also superior with knotless anchors, these differences in scores were not statistically significant (Table 3). Pain was the only variable that was linked to decreased RTP, as patients who rated higher on a pain scale of 0 to 10 were less likely to return to their sport (P < .0001). There was no correlation in outcome measures or RTP with gender, age, number of anchors, or sport type (P > .05). There was no statistically significant difference in RTP, KJOC, or ASES scores between non-overhead and overhead athletes (Table 4). Overall return to sport in throwers was 85.7% (24/28), while 39.3% (11/28) returned at the same level, 46.4% (13/28) at a lower level, and 14.3% (4/28) did not return to sport.

DISCUSSION

There was no significant difference between knotted and knotless fixation in clinical outcomes or return to sport in the repair of SLAP IIb tears; however, there was a trend toward knotless anchors requiring less revision surgery and having higher RTP, ASES, and KJOC scores than knotted fixation. Despite the inclusion of 74 patients, this study was significantly underpowered, as a power analysis calculated that over 300 athletes would be required in each group to detect a difference in the revision rate.

SLAP tears, traditionally treated with knotted suture anchors, have yielded varying results in the literature, with good to excellent results being reported in 65% to 94% of patients.^13-17 The success of SLAP repairs in athletes, especially overhead athletes, remains a difficult problem, as they are common injuries, and RTP is less predictable. Studies differ with regard to the percentage of overhead athletes who are able to return to their previous level of sport, with ranges being reported from 22% to 92%.^16,18,19 In a systematic review of 198 patients, Sayde and colleagues¹⁶ found that 63% of overhead athletes treated with anchor fixation, tacks, or staples were able to return to their previous level of play. Morgan and colleagues⁵ found a higher return to sport when compared with other studies, reporting that 83% of patients undergoing SLAP repairs using traditional suture anchors had excellent results, and 87% of the 53 overhead athletes had excellent results based on UCLA shoulder scores. Further, 37 of the 44 pitchers examined (84%) were able to return to their pre-injury levels.⁵ This is in contrast to Friel and colleagues²⁰ who found that in 48 patients with type II SLAP tears treated with traditional anchors, 23% reported excellent and 56% reported good results in regards to UCLA shoulder scores. Friel and colleagues also found that 62% of all athletes and 59% of overhead athletes were able to return to their previous levels of sport, which is similar to the current study.²⁰ The large discrepancy in RTP at the pre-injury level between this study and that of Morgan and colleagues⁵ may be due to the shorter minimum follow-up of 1 year as well as the inclusion of all subtypes of SLAP II tears in the latter. The current study had a minimum 2-year follow-up period, with an average of 6.5 years, and was limited to SLAP IIb tears. With a longer follow-up period, patient outcomes and RTP, particularly in overhead sports, may deteriorate; therefore, the current study likely shows a more complete and accurate result.

Knotless anchors were originally introduced as a less time consuming, lower profile, and simpler device to learn and use for arthroscopic procedures.²¹ Kocaoglu and colleagues²² found that in Bankart repairs, the mean time per anchor placement for knotted anchors was 380 seconds, whereas placement of knotless anchors took on average 225 seconds. A learning curve also exists for proper and efficient knot tying.⁷ There is also variation in knot tying between surgeons, as evidenced by a wide range in both load to failure and knot height.⁷ A study performed by Hanypsiak and colleagues⁷ found that the surgical knot was the weakest portion of the suture-anchor construct, as the knot’s load to failure was less than the pullout strength of the anchor.

There is also concern for the added height associated with traditional knotted fixation, which has been supported by case reports of knot-induced glenoid erosion after arthroscopic fixation of a SLAP tear.²³ Hanypsiak and colleagues⁷ also found that the average knot height occupied 50% to 95% of the space between the humeral head and the acromion when the shoulder is in a neutral position, indicating that the higher profile knotted anchors may contact the undersurface of the acromion, which could affect the labral repair as well as cause rotator cuff injury. Abrasion of the rotator cuff by a prominent knot may cause pain, tearing, and disability. A recent study by Park and colleagues²⁴ reported on 11 patients with knot-induced pain after type II SLAP repair. All complained of sharp pain, with 64% also complaining of clicking. Knot location did not seem to matter, as there was no difference in preoperative symptoms, with 5 of the 11 patients having knots on the glenoid side of the repair on repeat arthroscopy. Patients with knots on the labral side did, however, have humeral head cartilage damage. The knots appeared to be the cause of pain and clicking, as after arthroscopic knot removal, dramatic pain relief was seen, with Constant and UCLA scores significantly improving in all 11 patients. All patients also had positive preoperative compression-rotation testing, and at 6 weeks after surgical knot removal, all were negative.²⁴

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