Stability of novel cow-hitch suture button coracoid bone graft fixation in Latarjet procedures: a biomechanical study

BACKGROUND

The Latarjet procedure is widely used to address anterior shoulder instability, especially in case of glenoid bone loss. Recently, cortical suture button fixation for coracoid transfer has been used to mitigate complications seen with screw placement. The aim of this biomechanical study was to evaluate the stability of a novel and cost-effective cow-hitch suture button technique, designed to be performed through a standard open deltopectoral approach, and compare this to a well-established double suture button technique.

MATERIALS AND METHODS

We randomly assigned 12 fresh frozen cadaveric shoulders to undergo the Latarjet procedure with either 4 suture button (S&N EndoButton) fixations (SB group; n = 6, age 72 ± 9.8 years) or cow-hitch suture button technique using a 1.7-mm FiberTape looped sequentially in 2 suture buttons (Arthrex Pectoralis Button) placed from anterior on the posterior glenoid (CH-SB group; n = 6, age 73 ± 9.3 years). After fixation, all shoulders underwent biomechanical testing with direct loading on the graft via a material testing system. Cyclic loading was performed for 100 cycles (10-100 N) to determine axial displacement with time; each graft was then monotonically loaded to failure.

RESULTS

The maximum cyclic displacement was 4.3 ± 1.6 mm for the cow-hitch suture button technique and 5.0 ± 1.7 mm for the standard double suture button technique (P = .46). Ultimate load to failure and stiffness were, respectively, 190 ± 82 N and 221 ± 124 N/mm for the CH-SB technique and 172 ± 48 N and 173 ± 34 N/mm for the standard double SB technique (P = .66 and .43). The most common failure mode was suture cut-through at the anteroinferior aspect of the glenoid for both fixation groups.

CONCLUSIONS

The cow-hitch suture button technique resulted in a similar elongation, stiffness, and failure load compared to an established double suture button technique. Therefore, this cost-effective fixation may be an alternative, eligible for open approaches, to the established double suture button techniques.

Arthroscopic Latarjet procedure and suture-button fixation: can we predict nonunion early?

BACKGROUND

The arthroscopic Latarjet procedure is a technically challenging technique that provides well-known results. The first series reported fixation with screws. An alternative fixation technique has been proposed, using a button, to improve the reproducibility and to decrease the complications due to screws. The first reports using this fixation technique have yielded comparable rates of fusion. The objective of this study was to assess the fusion rate and bone modifications with this type of fixation.

METHODS

Two hundred sixteen patients were included in this prospective study. An arthroscopic Latarjet procedure, fixed with 1 button according to the Smith & Nephew technique, was performed by a single surgeon for the treatment of anterior instability. The radiographic protocol consisted of computed tomography scans at 3, 12, and 24 weeks postoperatively. We measured the coronal and sagittal positions of the bone block, distance between the bone block and the glenoid, diameter of the glenoid tunnel, fusion rate, and time to fusion.

RESULTS

The position was deemed flush in 92.6% of cases in the coronal plane and under the equator in 87.5% of cases in the sagittal plane. At last follow-up, we observed 9 cases of nonunion (4%), as well as 18 cases of delayed fusion. The fusion rate was 92% at 3 months and 96% at 6 months. For bone blocks that ultimately healed, the diameter of the glenoid tunnel was <2 mm in 62% of cases at 3 weeks and <1 mm in 90% of cases at 3 months. Conversely, the diameter of this tunnel significantly increased and was >3 mm in all cases of delayed union or nonunion.

CONCLUSION

The described technique achieved a reliable position of the bone block and a very good fusion rate with a new type of fixation. The time to obtain fusion can be lengthy, occurring between the third and sixth months. The diameter of the glenoid tunnel was the best predictive factor for fusion. Widening of the glenoid tunnel diameter >3 mm during the first 3 weeks was the most predictive factor for delayed union or nonunion of the bone block. This finding is probably explained by a sliding effect of the sutures through this tunnel, comparable to the bungee effect in anterior cruciate ligament repair in the knee.

Subpectoral biceps tenodesis with BicepsButton fixation in the young population: which technique works best?

BACKGROUND

Injuries of the long head of the biceps (LHB) tendon are a prevalent source of anterior shoulder pain and are commonly treated with tenodesis. Not only a stable fixation of the LHB but also anatomic restoration of the length-tension relationship plays a central role in providing satisfactory functional and cosmetic outcomes, especially in young patients. We report the clinical outcomes of 2 different subpectoral tenodesis techniques using unicortical button fixation.

METHODS

Patients aged ≤ 50 years who were treated between April 2015 and January 2020 with 1 of the 2 following subpectoral tenodesis techniques were retrospectively selected and enrolled to undergo a follow-up examination at least 2 years after surgery: subpectoral in situ tenodesis followed by resection of the intra-articular portion leaving a residual tendon stump in the bicipital groove (group I) vs. tenotomy followed by resection of the stump and subpectoral tenodesis (group II). Patients who underwent concomitant rotator cuff repair, subsequent shoulder surgery, or contralateral biceps surgery were excluded. Clinical outcomes were evaluated using the LHB score and the Constant-Murley Score (CMS), as well as measurements of isometric elbow flexion and forearm supination strength. Sonographic evaluation included assessment of the integrity of the LHB and tenodesis, examination for signs of inflammation within the sulcus or around the tendon, and measurements of the distalization of the myotendinous junction of the LHB compared with the nonoperative side.

RESULTS

A total of 34 patients comprising group I (24 men; mean age at time of surgery, 40.3 years; mean follow-up period, 57.2 months) and 24 patients comprising group II (19 men; mean age at time of surgery, 39.8 years; mean follow-up period, 51.9 months) were evaluated. The total CMS, as well as the scores for each CMS subcategory, did not reveal significant differences between the groups. The overall LHB score was on average 10 points higher in group I (mean, 94 points) than in group II (mean, 84 points) (P = .016). Regarding the LHB score subcategories, group I showed significantly better results for patient-dependent cosmesis (mean, 15 points in group I vs. 12 points in group II; P = .005) and examiner-dependent cosmesis (mean, 14 points in group I vs. 10 points in group II; P = .001). This finding was substantiated by a significantly higher distalization of the myotendinous junction in group II (mean, 3.0 cm in group I vs. 3.8 cm in group II; P = .030).

CONCLUSION

This study shows that subpectoral in situ tenodesis of the LHB followed by arthroscopic resection of the intra-articular portion provides higher LHB scores and better cosmetic outcomes compared with proximal intra-articular tenotomy followed by subpectoral tenodesis.

The safety and effectiveness comparison of Delta Medical's PEEK interface screw and Endobutton and that of Smith & Nephew's in arthroscopic anterior cruciate ligament reconstruction: A multicenter prospective double-blind randomized controlled clinical trial

Background

To reduce the costs and financial burden in the ACLR treatment, we compare the early clinical outcomes and Magnetic Resonance Imaging (MRI) results of Delta Medical's PEEK (polyether ether ketone) interference screw and EndoButton with those of Smith & Nephew's PEEK interference screw and EndoButton in patients with arthroscopic anterior cruciate ligament reconstruction.

Methods

A total of 104 patients in five different medical centers were randomly allocated into two groups: 1: Delta Medical's PEEK interference screw and EndoButton (53 patients); 2: Smith & Nephew's PEEK interference screw and EndoButton (51 patients). The modified Lysholm knee score, the laxity examination, and clinical and functional range of motion were evaluated at 3 and 6 months postoperatively. The clinical effective rate was calculated and classified as excellent and good at 6 months postoperatively. MRI examinations were performed at 3 and 6 months postoperatively to determine the healing process. Computerized tomography (CT) was performed at 2 weeks and 3 months postoperatively to evaluate the complications.

Results

Significant improvements in knee function and functional scores were observed in both groups after surgery regardless of the fixation materials applied (P < 0.05). No differences were observed in the functional scores and range of motion. The assessments of Lysholm knee scores at 3 and 6 months produced no statistical differences (both P > 0.05). The clinical effective rate revealed no difference between the groups at 6 months postoperatively (non-inferiority analysis P = 0.0220). The differences of laxity examination between the groups were not statistically significant (Fisher's test, P = 0.6139, 0.2004, respectively). No significant differences in the functional range of motion were found at each follow-up time-point (P > 0.05). No major intra- or postoperative complications, such as infection, and vessel or nerve injury were observed.

Conclusions

Knee function and functional scores were improved after ACLR in both groups, regardless of the PEEK interference screw and EndoButton applied. The difference in functional scores and range of motion were not significant in groups 1 and 2. Delta Medical's PEEK interference screw and EndoButton had a non-inferiority effect compared to Smith & Nephew's PEEK interference screw and EndoButton. Delta Medical's PEEK interference screw and EndoButton were suitable for arthroscopic ACLR.

Double-screw and quadruple-button fixation for the glenoid: Latarjet versus bone block applications

Background

The Latarjet and bone block procedures can be secured with screws or cortical buttons. The purpose of this biomechanical study was to compare quadruple buttons vs. double screws for fixation of anterior glenoid bone grafts.

Methods

Twelve cadaveric scapulae (6 pairs) were denuded, resected, and potted. Pairs were randomized to quadruple-button or double-screw fixation after creation of a 15% anterior glenoid defect. The specimens underwent cyclic uniaxial compressive glenoid loading between 50 and 200 N for 1000 cycles at 1 Hz. Testing was repeated for conjoint tendon loads of 0 N (simulating a bone block procedure), 10 N, and 20 N (simulating a Latarjet procedure). Peak resultant relative coracoid graft displacement was optically tracked at 3 points (superior, central, and inferior) on the edge of the coracoid.

Results

No significant differences were found between buttons and screws for bone block applications or with 10 N of conjoint tendon loading (P ≥ .095). At 20 N of conjoint tendon loading, however, the screws were significantly more stable than the buttons (P ≤ .023). During the initial 20-N conjoint load application, all 3 points displaced significantly more with the button reconstruction than with the screws (P ≤ .01). Overall, mean displacements did not exceed 1 mm at any position on the coracoid, regardless of testing condition.

Conclusions

The quadruple-button technique is comparable to screws when the coracoid is used as a bone block or when conjoint tendon loading is minimized. However, at higher conjoint tendon loads, the screws produced a more stable coracoid graft than the buttons.

Chronic distal biceps avulsion treated with suture button

BACKGROUND

Distal biceps tendon avulsions account for 3%-10% of all biceps ruptures. Treated nonoperatively, these injuries lead to a loss of endurance, supination strength, and flexion strength compared with operative repair or reconstruction. Operative management of chronic injury has classically been with graft tissue to augment the contracted muscle. We present our results for chronic distal biceps avulsions secured with suture button through a single transverse incision in high flexion without the need for allograft augmentation.

MATERIALS AND METHODS

This was a retrospective review of 20 patients with 21 injuries who underwent primary surgical repair of chronic distal biceps tendon avulsions at an average of 10 weeks (range 4-42 weeks). All patients were treated with a single transverse incision with a suture button armed with nonabsorbable no. 2 core sutures. Postoperatively patients were found to have 50°-90° flexion contracture. All patients were placed in a simple sling postoperatively with gentle extension to gravity as tolerated immediately and no formal physical therapy. Patients were surveyed regarding pre- and postoperative American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, visual analog scale (VAS) score, Mayo Elbow Performance Score (MEPS), Oxford Elbow Score (OES), and overall satisfaction. Range of motion (ROM), flexion, and supination strength compared to the contralateral uninjured extremity were evaluated at final follow-up.

RESULTS

Mean clinical follow-up was 26 months. All patients regained full ROM and 5/5 flexion and supination strength at final follow-up. MEPSs were 100 for all responding patients compared with an average 47.5 preoperatively (P < .0001). The mean postoperative ASES score was 97.2 compared with 41.9 preoperatively (P < .0001). Mean OESs pre- and postoperatively were 24.2 and 48, respectively (P < .0001). The mean VAS score was 4.4 preoperatively and was reported as 0 by all patients at final follow-up (P < .0001). Two patients had transient sensory radial nerve neuropathy, and 1 patient has persistent palsy. No synostoses occurred. Four patients reported supination fatigue postoperatively compared with the uninjured extremity.

CONCLUSION

Given these results, we feel that chronic distal biceps tendon ruptures can be repaired successfully with a single incision using suture button technique without the use of a graft. Though the flexion contracture is significant postoperatively, all patients regained full ROM and had excellent postoperative functional outcome scores.

Suture Button Technique for Tibialis Anterior Tendon Transfer for the Treatment of Residual Clubfoot

BACKGROUND

The Ponseti method has revolutionized the treatment of idiopathic clubfoot, but recurrence remains problematic. Dynamic supination is a common cause of recurrence, and the standard treatment is tibialis anterior tendon transfer using an external button. Although safe and effective, the placement of the button on the sole creates a pressure point, which can lead to skin ulceration. In our institution, a suture button has been used for the tibialis anterior tendon transfer and we report our results here.

METHODS

Two senior authors' case logs were retrospectively reviewed to identify 23 patients (34 feet) for tibialis anterior tendon transfer using a suture button. Complications and additional operative procedures were assessed by reviewing operative notes, follow-up visit clinic notes, and radiographs. The mean age of the patients was 6 years 2 months (SD 40 months) and the average follow-up duration was 67.1 weeks (SD 72 weeks).

RESULTS

There were 5 complications (14.7%). Recurrence occurred bilaterally in 1 patient (5.9%) but did not require reoperation. Other complications included a cast-related pressure sore (2.9%) and an infection (2.9%) requiring irrigation with debridement along with hardware removal.

CONCLUSIONS

Tibialis anterior tendon transfer using a suture button was a safe procedure with theoretical advantage of providing stronger fixation and reducing the risk of skin pressure necrosis compared to the standard external button technique. We believe a suture button could allow earlier rehabilitation and may afford stronger ankle eversion. Prospective studies are required to compare the differences in functional outcomes between the procedures.

LEVEL OF EVIDENCE

Level IV, case series, therapeutic study.

In vivo comparison of a fixed loop (EndoButton CL) with an adjustable loop (TightRope RT) device for femoral fixation of the graft in ACL reconstruction: A prospective randomized study and a literature review

INTRODUCTION

There is a lack of in vivo studies comparing the functional outcome and knee stability after anterior cruciate ligament reconstruction (ACLR) using fixed loop (EndoButton (EB) CL) and adjustable loop (TightRope (TR) RT) devices for femoral fixation of soft tissue grafts.

MATERIALS AND METHODS

Functional outcomes were assessed in terms of the International Knee Documentation Committee (IKDC) and Lysholm scores, knee stability by anteroposterior laxity and side-to-side difference (SSD) using KT-1000 arthrometer. The evaluation was performed preoperatively and post-operatively at 6 months and 2 years.

RESULTS

Both groups were matched in terms of demographic, preoperative, intraoperative and post-operative covariates. EB ( n = 52) appeared to have better IKDC and Lysholm scores at 6 months post-operative when compared to TR ( n = 50). However, at a final follow-up of 2 years, the results were similar. The anterior tibial translation and SSD were statistically insignificant between the two groups at 6 months and 2 years.

CONCLUSION

ACLR using EB or TR for femoral fixation gives substantially equivalent functional results and knee stability at mid-term follow-up.

Biomechanical Comparison of Suture-External Button Fixation vs Internal Suspension Fixation for Tendon Transfers of the Feet

BACKGROUND

Fixation of tendon transfers in pediatric feet typically involves passing a suture that is secured to a tendon, through an intraosseous tunnel, and tying it over an external button on the plantar foot, with appropriate tension. After adequate time is allowed for bone-tendon healing, the suture and button are removed. This construct can be complicated by suture breakage with loss of fixation, and/or skin ulceration under the button. Internal suspension systems of tendons and ligaments in adults have demonstrated excellent fixation strength and minimal intraosseous tunnel displacement, with no risk of skin ulceration and no need for suture and button removal. This study compared the biomechanical properties of the suture-external button and internal suspension fixation techniques in cadavers. The primary outcome and secondary outcomes were displacement of suture-fixation construct during dynamic loading, and static loading, respectively.

METHODS

Nine adult cadaver feet were obtained. Both the external button and internal suspension techniques were tested once in each cadaver, in random order. Relative displacement of the fixation construct within the bone tunnel was recorded with video capture during dynamic and static loading. A custom Matlab script processed video and materials testing data. Static and cyclic displacements were analyzed between fixation groups using a paired t test (alpha value =0.05).

RESULTS

Internal suspension fixation had significantly less mean displacement of the tendon within the bone tunnel than the external button technique during dynamic (0.3 mm internal suspension system, 0.7 mm external button, P = .0115) and static loading (0.4 mm internal suspension system, 2.2 mm external button, P = .0019).

CONCLUSIONS

Internal suspension systems may provide superior fixation compared to the traditional external button for tendon transfers, with the added benefit of avoiding the risk of skin ulceration and the need for suture and button removal.

CLINICAL RELEVANCE

It appears internal suspension method of tendon transfer fixation would be an acceptable alternative to traditional methods of fixation with an external button.

Bone-to-bone integrations were complete within 5 months after anatomical rectangular tunnel anterior cruciate ligament reconstruction using a bone-patellar tendon-bone graft

PURPOSE

Anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone (BTB) graft is known to provide secure fixation due to the direct bone-to-bone integration of the bone plug and bone tunnel. It is important to know the time required for bone integration when designing the postoperative rehabilitation protocol or deciding when the patient can return to competition-level activity, especially if the patient is an athlete. However, because reports are scarce, the period necessary for bone-to-bone integration after ACL reconstruction using a BTB graft remains unclear. The purpose of this study was to clarify this issue. It was hypothesised that ACL reconstruction using a BTB graft via an anatomical rectangular tunnel would help in the integration between bone plugs and bone tunnels on both the femoral and tibial sides after at least 6 months, at which point basic exercises similar to pre-injury sporting activity levels can be resumed.

METHODS

This study included 40 knees treated with ACL reconstruction using a BTB graft via anatomical rectangular tunnel reconstruction between 2013 and 2014 in a single institute. The integration between bone plugs and bone tunnels was evaluated using multi-slice tomosynthesis, which is a technique for producing slice images using conventional radiographic systems, at 1, 3, and 5 months postoperatively. All procedures were performed by two experienced surgeons. Bone integration was evaluated by two orthopaedic doctors.

RESULTS

The rates of integration of the bone plug and femoral bone tunnel on tomosynthesis at 1, 3, and 5 months postoperatively were 0, 55, and 100%, respectively. On the tibial side, the corresponding rates were 0, 75, and 100%, respectively. The rate of integration on the tibial side was significantly higher than that on the femoral side at 3 months postoperatively (p = 0.031).

CONCLUSIONS

Bone-to-bone integration on the femoral and tibial sides was complete within 5 months after surgery in all cases. Since the time required for bone integration is important in designing the postoperative rehabilitation approach, these results will serve as a useful guideline for planning rehabilitation protocols.

LEVEL OF EVIDENCE

IV.

Treatment of Distal Biceps Tendon Injuries with Particular Emphasis on Postoperative Physiotherapy

Distal biceps tendon injuries are relatively rare. Standard treatment of complete tears and significant partial tears involves surgical anatomical reinsertion of the tendon at the radial tuberosity. Chronic injuries are usually managed with surgical tendon reconstruction using autografts or allografts. Conservative treatment is mostly limited to the elderly, individuals with a very low level of physical activity, patients with evident contraindications to surgical treat-ment, and cases of mild partial tendon tears. The selection of an optimum surgical technique and method of fixation remains controversial. The aim of this paper is to characterize distal biceps tendon injuries, discuss methods of their surgical treatment, and analyze postoperative physiotherapy regimens described in the literature. A literature review did not reveal any relationship between the surgical method and type of fixation used on the one hand and the period of immobilization, type of immobilization, or the postoperative physiotherapy regimen on the other.

Secure fixation of femoral bone plug with a suspensory button in anatomical anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft

PURPOSE

the efficacy and safety of using a suspensory button for femoral fixation in anatomical anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BPTB) graft have not been established. The purpose of the current study was to evaluate bone plug integration onto the femoral socket and migration of the bone plug and the EndoButton (EB) (Smith & Nephew, Andover, MA, USA) after rectangular tunnel ACL reconstruction with BPTB autograft.

METHODS

thirty-four patients who underwent anatomical rectangular ACL reconstruction with BPTB graft using EB for femoral fixation and in whom three-dimensional (3D) computed tomography (CT) was performed one week and one year after surgery were included in this study. Bone plug integration onto the femoral socket, bone plug migration, soft tissue interposition, EB migration and EB rotation were evaluated on 3D CT. The clinical outcome was also assessed and correlated with the imaging outcomes.

RESULTS

the bone plug was integrated onto the femoral socket in all cases. The incidence of bone plug migration, soft tissue interposition, EB migration and EB rotation was 15, 15, 9 and 56%, respectively. No significant association was observed between the imaging outcomes. The postoperative mean Lysholm score was 97.1 ± 5.0 points. The postoperative side-to-side difference, evaluated using a KT-2000 arthrometer, averaged 0.5 ± 1.3 mm. There were no complications associated with EB use. Imaging outcomes did not affect the postoperative KT side-to-side difference.

CONCLUSIONS

the EB is considered a reliable device for femoral fixation in anatomical rectangular tunnel ACL reconstruction with BPTB autograft.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Mechanical properties of suspensory fixation devices for anterior cruciate ligament reconstruction: comparison of the fixed-length loop device versus the adjustable-length loop device

BACKGROUND

No definite consensus has been reached regarding the optimal technique for graft fixation to the femur in an anterior cruciate ligament reconstruction. The purpose of this study was to evaluate the mechanical strength of two cortical suspension devices which were the TightRope (TR), a new adjustable-length loop device, and the EndoButton (EB), a well-established fixed-length loop device.

METHODS

The devices were tested under cyclic and pull-to-failure loading conditions in both an isolated device setup and a specimen setup using porcine femora and bovine flexor tendons. In particular, we examined the influence of tendon and device lengths, whereby the total length of the bone tunnel was fixed to 35 mm and an effective length of tendon in the bone tunnel was adjusted.

RESULTS

In the isolated device testing, the EB showed significantly higher ultimate tensile strength than the TR. The displacement after preloading for the EB was statistically lower than that for the TR, and retained a significant difference after the cyclic load. In contrast, specimen testing showed no statistical difference in the displacement among the EB group and TR groups.

CONCLUSION

This study indicated that the EB provides greater mechanical strength than the TR. An important new finding was the measurement of initial displacement from the initiation of fixation until loading began using 50 N of tension. In isolated device testing, the TR induced significantly more displacement than the EB during preloading, which could reflect the TR loop's stretching capacity until a certain amount of tension is applied.

Femoral suspension devices for anterior cruciate ligament reconstruction: do adjustable loops lengthen?

BACKGROUND

Cortical suspension devices are commonly used for femoral graft fixation during anterior cruciate ligament (ACL) reconstructive surgery. Adjustable-length fixation devices provide technical advantages over fixed-length loops but may be more susceptible to lengthening during cyclic loading.

HYPOTHESIS

Both fixed-length and adjustable-length femoral cortical suspension devices would withstand ultimate loads greater than those normally experienced by the native ACL and would prevent clinically significant lengthening during prolonged cyclic loading.

STUDY DESIGN

Controlled laboratory study.

METHODS

Mechanical testing was performed on 3 ACL graft cortical suspensory devices by use of an extended cyclic loading (4500 cycles at 10-250 N) and pull-to-failure protocol. Two adjustable-length devices were additionally tested with the free suture ends tied.

RESULTS

Total displacement after 4500 cycles of tensioning at variable loads (expressed as mean ± SD) was 42.45 mm (±7.01 mm) for the Arthrex TightRope RT, 5.76 mm (±0.35 mm) for the Biomet ToggleLoc, and 1.34 mm (±0.03 mm) for the Smith & Nephew EndoButton CL Ultra (P < .001). The Arthrex TightRope reached clinical failure of 3 mm lengthening after fewer cycles (1349 ± 316) than the Biomet ToggleLoc (2576 ± 73) (P < .001). The Smith & Nephew EndoButton did not reach clinical failure during cyclic testing. With the free suture ends tied, after 4500 cycles, the Arthrex TightRope had a significant decrease in lengthening to 13.36 ± 1.86 mm (P < .037) There was also a significant difference in ultimate load between the TightRope (809.11 ± 52.94 N) and the other 2 constructs (P < .001).

CONCLUSION

The ultimate load of all graft-fixation devices exceeded the forces likely to be experienced in a patient's knee during the early postoperative rehabilitation period. However, the adjustable-length fixation devices experienced a clinically significant increase in loop lengthening during cyclic testing. This lengthening is partially caused by suture slippage into the adjustable-length loop.

CLINICAL RELEVANCE

Adjustable-length ACL graft cortical suspension devices lengthen under cyclic loads because free suture ends are pulled into the adjustable loop. This may allow for graft-fixation device lengthening during the acute postoperative period.