The Biomechanical Properties of a High-Tensile Strength Tape for Tendon Graft Fixation Using the Krackow Configuration

Ligament Augmentation Reconstruction System (LARS) for Ankle Lateral Ligament Reconstruction in Higher-Risk Patients: A 5-Year Prospective Cohort Study

Background:

The modified Broström-Gould (MBG) procedure is the gold standard for patients with chronic ankle instability (CAI), but it is relatively contraindicated for patients with higher body weight or generalized ligamentous laxity (GLL). The use of the ligament augmentation reconstruction system (LARS) is an alternative.

Hypothesis:

It was hypothesized that clinical outcomes would be similar in patients with increased body weight (>90 kg) or GLL, relative to controls.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 66 patients satisfying the inclusion criteria were invited to participate and were divided into 3 groups: controls (no risk factors for inferior clinical outcome), patients with body weight >90 kg, and patients with GLL (Beighton score, ≥5 of 9). All patients underwent imbrication of the lateral collateral ligament complex augmented with the LARS. Primary outcomes of interest were Tegner activity scale (TAS) and Foot and Ankle Outcome Score (FAOS) subscale scores. Secondary outcomes were recurrence of ankle instability, the need for further surgery, and/or complications. Patients were reviewed at 2 and 5 years postoperatively, and outcomes between groups were compared using repeated-measures analysis of variance.

Results:

Complete data were available for 63 patients (21 patients in each group). TAS improved in all groups from preoperatively to 2 years and 5 years postoperatively (P < .001 for all). Relative to the controls, the TAS scores were lower in the >90-kg group at 2 years and 5 years (P < .001 for both periods), while the GLL group had similar scores to controls at both postoperative periods. Both the >90-kg and the GLL groups showed no significant difference in improvement on any FAOS subscale scores relative to the controls, at both 2 and 5 years postoperatively. There were no recurrences, repeat surgeries, or major complications.

Conclusion:

Relative to controls, patients with body weight >90 kg or GLL had similar FAOSs, and TAS scores were lower in the >90-kg group, at 2 and 5 years, after the use of the LARS to augment lateral collateral ligament imbrication for CAI. Use of the LARS in this manner is a viable option in patients for whom the MBG procedure is relatively contraindicated.

Knots Tied With High-Tensile Strength Tape Biomechanically Outperform Knots Tied With Round Suture

Background

Tape-type suture material is well-accepted in arthroscopy surgery.

Purpose

To compare the knot security of a high-tensile strength round suture and high-tensile strength tape with commonly used arthroscopic knots.

Study Design

Controlled laboratory study.

Methods

We compared the performance of No. 2 braided nonabsorbable high-strength suture with that of 1.3-mm braided nonabsorbable high-strength tape. Five commonly used arthroscopic knots were investigated: the Roeder knot; the Western knot; the Samsung Medical Center (SMC) knot; the Tennessee knot; and a static surgeon's knot. Seven knots were tied for each combination of knots and suture types. Knots were tied on a 30-mm circumferential metal post, and the suture loops were transferred to a materials testing machine. After preloading to 5 N, all specimens were loaded to failure. The clinical failure load, defined as the maximal force to failure at 3 mm of crosshead displacement, yield load, and stiffness, were recorded. A 2-way analysis of variance was used to determine differences between the groups.

Results

Both suture type and knot type significantly affected the clinical failure load, yield load, and stiffness (P = .002). The high-strength tape resulted in a significantly greater clinical failure load than the high-strength suture in the case of the Roeder knot, Western knot, and SMC knot (P = .027, .005, and .016, respectively). When the high-strength round suture was used, the Roeder knot, Western knot, and SMC knot resulted in significantly smaller clinical failure loads compared with the Tennessee knot (P = .011, .003, and .035, respectively) and the static surgeon's knot (P < .001 for all). When the high-strength tape was used, the Roeder knot, Western knot, and SMC knot resulted in significantly smaller clinical failure loads compared with the static surgeon's knot (P = .001, .001, and .003, respectively).

Conclusion

The results of this study indicated that arthroscopic knots tied using 1.3-mm high-strength tape biomechanically outperformed knots tied using a No. 2 high-strength suture. While the static surgeon's knot exhibited the best biomechanical properties, the Tennessee knot resulted in generally better biomechanical properties among the arthroscopic sliding knots.

Clinical Relevance

Elongation and loosening of tied knots possibly affects the clinical results of repaired constructs.

Does using high-tensile strength tape improve the fixation strength in tendon graft fixation with needleless suture wrapping techniques compared to a suture?

PURPOSE

To compare the biomechanical properties of a high-tensile strength suture and high-tensile strength tape in tendon graft fixation using two needleless suture wrapping techniques, the modified Prusik knot and modified rolling hitch.

METHODS

Two needleless suture wrapping techniques, the modified rolling hitch (MR) and modified Prusik knot (MP), were utilized. Meanwhile, two kinds of suture materials, a No. 2 braided nonabsorbable high-strength suture (S) and a 1.3 mm high-tensile strength tape (T), were used. A total of 40 porcine tendons were used, which were randomly divided into four groups. Each group was assigned to one of the following groups: MRS, MRT, MPS, and MPT. Each specimen was pretensioned to 100 N for three cycles, cyclically loaded from 50 to 200 N for 200 cycles, and finally loaded to failure.

RESULTS

The MRT group (34.1 ± 3.5%) had a significantly higher value compared with the MRS (29.7 ± 2.3%), MPS (27.1 ± 3.6%) and MPT (29.5 ± 4.0%) groups in term of elongation after cyclic loadings (p = 0.002). In terms of ultimate failure load, there were no significant differences in the MRS (401 ± 27 N), MRT (380 ± 27 N), MPS (398 ± 44 N) and MPT (406 ± 49 N) values (p = 0.539). All specimens failed due to suture breakage at the knots.

CONCLUSION

Compared with the high-tensile strength suture, using the high-tensile strength tape lead to greater elongation after cyclic loading when the modified rolling hitch was used. No differences in terms of elongation after cyclic loading and load to failure were found between the high-tensile strength suture and tape using the modified Prusik knot.