The effect of abduction and rotation on footprint contact for single-row, double-row, and modified double-row rotator cuff repair techniques

Posterior Medial Meniscus Root Repair Using Two Transtibial Tunnels with Modified Mason-Allen Stitches: A Technical Note

Complete tear of the posterior medial meniscus root can result in a loss of hoop tension and increased contact pressure. Thus, medial meniscus posterior root tear (MMPRT) is increasingly recognized as an important pathology. Although several surgical techniques for MMPRT have recently been introduced, the ideal technique is not yet established. This technical note is aimed at introducing a novel surgical technique using two transtibial tunnels with modified Mason-Allen stitches in the treatment of MMPRT.

Arthroscopic single anchor repair techniques for upper third subscapularis tears provide sufficient biomechanical stability

PURPOSE

Upper third tears of the subscapularis tendon can be repaired successfully with a single anchor according to previous literature. The aim of the present study was to compare three single anchor repair techniques regarding fixation strength, footprint coverage and contact pressure in a biomechanical test set-up on human cadaveric shoulders.

METHODS

Eighteen human cadaveric shoulders were randomized in three groups with respect to the repair technique; group 1: knotted lasso-loop mattress, group 2: knotted mattress and group 3: knotless tape repair. Upper third tears of the subscapularis tendon (Lafosse type 2) were created and repairs were performed with additional contact pressure and area measurement using a pressure mapping system. Cyclic testing was performed by loading the subscapularis from 10 to 100 N for 300 cycles. A position-controlled ramp protocol up to 30 and 50 N was used to allow for pressure measurements. Finally, specimens were loaded to failure and failure modes were recorded.

RESULTS

The three groups were not significantly different regarding age, gender, bone mineral density at the lesser tuberosity, subscapularis footprint size and defect area created at the upper subscapularis insertion. A significant difference was detected between group 1 (48.6 ± 13.8%) and group 2 (25.9 ± 5.7%) regarding pressurized footprint coverage (p = 0.028). Ultimate load to failure was 630.8 ± 145.3 N in group 1, 586.9 ± 220.7 N in group 2 and 678.2 ± 236.5 N in group 3, respectively. Cyclic displacement was similar in all three groups with an average displacement of 1.2 ± 0.6 mm. The highest stiffness was found in group 1 with 88 ± 30.3, which was not statistically significantly different to group 2 (65 ± 27 N/mm) and group 3 (83.9 ± 32.9 N/mm). The most common mode of failure was suture cut-through at the suture-tendon interface (44%). Failures in group 3 were less common associated with suture cut-through (33% vs. 50% in group 1 and 2), but no significant differences were found.

CONCLUSIONS

All three tested single anchor repair techniques of upper third subscapularis tears were able to provide sufficient biomechanical stability. Knotted lasso-loop mattress and knotless tape repair were superior regarding pressurized footprint coverage compared to a knotted horizontal mattress technique and are, therefore, preferable techniques for upper subscapularis repair.

Double-Row Suture Anchor Fixation and Achilles Allograft Augmentation for Chronic Patellar Tendon Rupture Repair

Patellar tendon ruptures are functionally devastating injuries that result in failure of the knee extensor mechanism and can lead to a loss of ambulation. Chronic patellar tendon injuries are defined as tears greater than 2 weeks old and are typically more complex to manage than acute tears. Recently, the use of double-row suture anchor configurations has been explored as a technique to provide improved strength in addition to tendon-to-bone compression at the anatomic footprint. The purpose of this article is to describe a surgical technique involving chronic patellar tendon rupture repair using a double-row suture construct augmented with Achilles allograft. Our technique offers a variety of benefits and permits early postoperative mobilization.

Editorial Commentary: Anterior Cable Reconstruction for the Shoulder Superior Capsule: Time for "Indication Rounds"

Anterior cable reconstruction (ACR) techniques for the superior capsule are multiple and varied. To optimize patient outcomes, technical considerations must be supported by basic science, both anatomically and biomechanically. ACR was designed to treat only partially repairable rotator cuff tendon tears, to provide a static support to a dynamic partial (and therefore "nonanatomic") repair, and to treat tears that could not be treated by transosseous-equivalent footprint-restoring "anatomic" repairs (both capsule and tendon repaired), but were also not so large as to necessitate superior capsule reconstruction. ACR allows restoration of posterosuperior capsular function with side-to-side repair sutures, and much of the biomechanical functionality comes from using whatever inherent native superior capsule is available. Cable reconstructions should be secured to normal attachment sites on the glenoid and greater tuberosity sulcus. Also, graft tension must be accounted for when considering humeral motion such as rotation and adduction. The indications for ACR need to be carefully considered and account for both anatomic and biomechanical rationales. In the face of new ACR techniques, the need to discern what is possible versus what procedure is indicated cannot be overlooked.

Anterior Cable Reconstruction of the Superior Capsule Using Semitendinosus Allograft for Large Rotator Cuff Defects Limits Superior Migration and Subacromial Contact Without Inhibiting Range of Motion: A Biomechanical Analysis

PURPOSE

To biomechanically assess translation, contact pressures, and range of motion for anterior cable reconstruction (ACR) using hamstring allograft for large to massive rotator cuff tears.

METHODS

Eight cadaveric shoulders (mean age, 68 years) were tested with a custom testing system. Range of motion (ROM), superior translation of the humeral head, and subacromial contact pressure were measured at 0°, 30°, 60°, and 90° of external rotation (ER) with 0°, 20°, and 40° of glenohumeral abduction. Three conditions were tested: intact, stage III tear (supraspinatus + anterior half of infraspinatus), and stage III tear + allograft ACR (involving 2 supraglenoid anchors for semitendinosus tendon allograft fixation. Allograft ACR included loop-around fixation using 3 side-to-side sutures and an anchor at the articular margin to restore capsular anatomy along the anterior edge of the cuff defect.

RESULTS

ACR with allograft for stage III tears showed significantly higher total ROM compared with intact at all angles (P ≤ .028). Augmentation significantly decreased superior translation for stage III tears at 0°, 30°, and 60° ER for both 0° and 20° abduction, and at 0° and 30° ER for 40° abduction (P ≤ .043). Augmentation for stage III tears significantly reduced overall subacromial contact pressure at 30° ER with 0° and 40° abduction, and at 60° ER with 0° and 20° abduction (P ≤ .016).

CONCLUSION

Anterior cable reconstruction using cord-like allograft semitendinosus tendon can biomechanically improve superior migration and subacromial contact pressure (primarily in the lower combined abduction and rotation positions), without limiting range of motion for large rotator cuff tendon defects or tears.

CLINICAL RELEVANCE

In patients with superior glenohumeral instability, using hamstring allograft for ACR may improve rotator cuff tendon defect longevity by providing basic static ligamentous support to the dynamic tendon while helping to limit superior migration, without restricting glenohumeral kinematics.

Anterior Cable Reconstruction Using the Proximal Biceps Tendon for Large Rotator Cuff Defects

Tears of the rotator cuff tendons can occur that do not allow anatomic footprint restoration yet may not be large enough to require a superior capsular reconstruction technique. Typically, these intermediate-sized tears are addressed with a medialized repair or partial repair technique. A partially repaired rotator cuff tendon, however, can lead to a high retear rate, as the repaired tendon is required to serve as both a dynamic tendon and a static ligamentous stabilizer. One potential static support, as a nearby autologous graft donor, is the proximal long head biceps tendon. The purpose of this Technical Note is to describe a surgical technique for an anterior cable reconstruction using the proximal biceps tendon for large rotator cuff defects.

Flexor Pollicis Longus Tendon Wear Associated With Volar Plating: A Cadaveric Study

PURPOSE

This study examined the effect of low-profile volar rim plates (VR), proximally placed standard variable-angle locking plates (pVA-LCP), and distally placed standard variable-angle locking plates (dVA-LCP) on the flexor pollicis longus (FPL) tendon in a cadaver model. We hypothesized that tendons from the VR and pVA-LCP groups would exhibit similar contact pressures, wear patterns, and post-fatigue testing mechanical properties, whereas dVA-LCP tendons would exhibit higher contact pressures, increased tendon wear patterns, and decreased mechanical properties.

METHODS

Nine matched pairs of cadaveric specimens were used in this study. Thin-film pressure sensors were used to measure the initial contact loads between plates and FPL tendons. Specimens were cyclically loaded for 10,000 cycles by actuating the FPL tendon. Cycled tendons were harvested, photographed with a stereomicroscope, and graded for wear on a Likert scale by 5 observers who were blinded to the study protocol. Uniaxial tensile testing measured mechanical properties of the tendon: ultimate failure load, ultimate stress, percent stress relaxation, elastic modulus, and stiffness.

RESULTS

With regard to the cadaveric FPL tendon, VR and dVA-LCP had increased contact pressure and tendon wear compared with pVA-LCP. There were no significant differences in contact pressure or tendon wear between dVA-LCP and VR. There was no major difference in the tested mechanical properties of the FPL tendon among any of the groups.

CONCLUSIONS

Plates placed directly on or beyond the volar rim demonstrate increased contact pressures and increased tendon wear in a cadaveric model.

CLINICAL RELEVANCE

Although low-profile plates allow for fixation of smaller volar fragments in the distal radius, they cause substantial contact with the FPL tendon, which may rupture if the plate is not removed.

Distal Patellar Tendon SpeedBridge Repair

Patellar tendon ruptures are rare injuries in young athletes, resulting in disruption of the extensor mechanism, and require surgery for functional recovery. Several techniques have been reported, including end-to-end repair and single-row suture anchor constructs. The strength of these repairs has been questioned, and they are commonly augmented. We endorse a double-row repair technique that provides an anatomic restoration of the footprint, has high fixation strength, eliminates the need for graft augmentation, and allows early motion.

Transection of the medial meniscus anterior horn results in cartilage degeneration and meniscus remodeling in a large animal model

The meniscus plays a central load-bearing role in the knee joint. Unfortunately, meniscus injury is common and can lead to joint degeneration and osteoarthritis (OA). In small animal models, progressive degenerative changes occur with the unloading of the meniscus via destabilization of the medial meniscus (DMM). However, few large animal models of DMM exist and the joint-wide initiation of the disease has not yet been defined in these models. Thus, the goal of this study is to develop and validate a large animal model of surgically induced DMM and to use multimodal (mechanical, histological, and magnetic resonance imaging) and multiscale (joint to tissue level) quantitative measures to evaluate degeneration in both the meniscus and cartilage. DMM was achieved using an arthroscopic approach in 13 Yucatan minipigs. One month after DMM, joint contact area decreased and peak pressure increased, indicating altered load transmission as a result of meniscus destabilization. By 3 months, the joint had adapted to the injury and load transmission patterns were restored to baseline, likely due to the formation and maturation of a fibrovascular scar at the anterior aspect of the meniscus. Despite this, we found a decrease in the indentation modulus of the tibial cartilage and an increase in cartilage histopathology scores at 1 month compared to sham-operated animals; these deleterious changes persisted through 3 months. Over this same time course, meniscus remodeling was evident through decreased proteoglycan staining in DMM compared to sham menisci at both 1 and 3 months. These findings support that arthroscopic DMM results in joint degeneration in the Yucatan minipig and provide a new large animal testbed in which to evaluate therapeutics and interventions to treat post-traumatic OA that originates from a meniscal injury.

Biomechanical comparison of knotless wide suture double-row SutureBridge rotator cuff repair to double-row standard suture repair

BACKGROUND

A comparison of self-reinforcement and footprint compression between standard- and wide-diameter suture material in double-row SutureBridge repair techniques has not been performed. The aim of this study was to compare the self-reinforcement and footprint contact pressure generated under progressive tensile loads between 2 double-row SutureBridge rotator cuff repair techniques: 1 performed with FiberWire and 1 performed with FiberTape in a knotless technique.

MATERIALS AND METHODS

Rotator cuff repairs were performed in 10 pairs of ovine shoulders. One group underwent a double-row SutureBridge repair using FiberWire. The other group underwent an identical repair with FiberTape. Footprint contact pressure was measured from 0° to 60° of abduction under loads of 0-60 N. Pull-to-failure tests were then performed.

RESULTS

In both repair constructs at 0° of abduction, each 10-N increase in rotator cuff tensile load led to a significant increase in footprint contact pressure (P < .05). The rate of increase in footprint contact pressure was greater in the FiberTape construct (ratio, 1.68; P = .00035). In both repair constructs, the highest values for footprint contact pressure were seen at 0° of abduction. No difference in pull to failure, peak load, or total energy was found between the groups.

CONCLUSION

Self-reinforcement was seen in both double-row SutureBridge repairs with standard- and wide-diameter suture material but was greater in the repair with the wide-diameter suture material construct. Footprint compression is greater in a knotless double-row SutureBridge repair with wide-diameter suture material than in a knotted double-row SutureBridge repair with standard-diameter suture material at 20° of abduction.

Biomechanical evaluation of a novel double rip-stop technique with medial row knots for rotator cuff repair: an in vitro study

Aims

Many biomechanical studies have shown that the weakest biomechanical point of a rotator cuff repair is the suture-tendon interface at the medial row. We developed a novel double rip-stop (DRS) technique to enhance the strength at the medial row for rotator cuff repair. The objective of this study was to evaluate the biomechanical properties of the DRS technique with the conventional suture-bridge (SB) technique and to evaluate the biomechanical performance of the DRS technique with medial row knots.

Methods

A total of 24 fresh-frozen porcine shoulders were used. The infraspinatus tendons were sharply dissected and randomly repaired by one of three techniques: SB repair (SB group), DRS repair (DRS group), and DRS with medial row knots repair (DRSK group). Specimens were tested to failure. In addition, 3 mm gap formation was measured and ultimate failure load, stiffness, and failure modes were recorded.

Results

The mean load to create a 3 mm gap formation in the DRSK and DRS groups was significantly higher than in the SB group. The DRSK group had the highest load to failure with a mean ultimate failure load of 395.0 N (SD 56.8) compared to the SB and DRS groups, which recorded 147.1 N (SD 34.3) and 285.9 N (SD 89.8), respectively (p < 0.001 for both). The DRS group showed a significantly higher mean failure load than the SB group (p = 0.006). Both the DRS and DRSK groups showed significantly higher mean stiffness than the SB group.

Conclusion

The biomechanical properties of the DRS technique were significantly improved compared to the SB technique. The DRS technique with medial row knots showed superior biomechanical performance than the DRS technique alone.

Footprint coverage comparison between knotted and knotless techniques in a single-row rotator cuff repair: biomechanical analysis

Abstract

Background

The objective of this biomechanical study is to compare two variations of single-row knotless techniques (Knotless repair and Rip-stop Knotless repair) against a single-row double-loaded anchor (DL) repair, focused on evaluating contact pressure and contact area amongst three different single-row techniques for rotator cuff repairs.

Methods

A total of 24 fresh frozen human shoulders were tested. Specimens were randomly assigned into one of the three single-row (SR) repair groups: A Knotted single-row double-loaded anchor (DL) repair, a Knotless (K) repair, or a Knotless Rip-Stop (KRS) repair. The footprint was measured after complete detachment of the supraspinatus tendon from the greater tuberosity, introducing pressure sensors between bony footprint and detached rotator cuff, and finally reconstructing it. All specimens were mounted onto a servohydraulic test system to analyze contact variables at 0° and 30° of abduction with 0 N, 30 N and 50 N of tension.

Results

Groups did not differ significantly in their footprint sizes: DL group 359.75 ± 58.37 mm², K group 386.5 ± 102.13 mm², KRS group 415.87 ± 93.80 mm² (p = 0.84); nor in bone mineral density: DL group 0.25 ± 0.14 g/cm², K group 0.32 ± 0.19 g/cm², KRS group 0.32 ± 0.13 g/cm², (p = 0.75) or average age. The highest mean pressurized contact area measured for the K repair was 248.1 ± 50.9 mm², which equals a reconstruction of 67.1 ± 19.3% at 0° abduction and a 50 N supraspinatus load. This reconstructed area was significantly greater compared with the DL repair 152.8 ± 73.1 mm², reconstructing 42.0 ± 18.5% on average when under the same conditions (p = 0.04). The mean contact pressure did not significantly differ amongst groups (p = 1.0): DL group 30.8 ± 17.4 psi, K group 30.9 ± 17.4 psi and KRS group 30.0 ± 10.9 psi. Neither the 30° abduction angle nor the supraspinatus load had a significant influence on the contact pressure in our study.

Conclusion

Both single-row knotless techniques resulted in significantly higher footprint reconstruction, providing larger contact area and a more uniform pressure distribution when compared with the single-row Knotted techniques. The mean contact pressure did not differ among groups significantly. These knotless techniques may be an alternative if the surgeon decides to perform a single-row rotator cuff repair.

Level of evidence

Basic Science Study, Biomechanics.

Different suture anchor fixation techniques affect contact properties in humeral greater tuberosity fracture: a biomechanical study

Background

Suture anchor-based fixations of humeral greater tuberosity (GT) fractures have yielded good outcomes in both clinical and biomechanical studies. Be that as it may, the interface contact properties of these fixations have yet to be elaborated. In response, the contact characteristics of two double-row suture anchor fixations for the management of GT fracture were compared.

Methods

Two suture anchor-based fixation techniques, namely the Double-Row Suture Anchor Fixation (DR) and Suture-Bridge Technique (SB), were used to repair humeral GT fractures in 12 fresh-frozen human cadaveric shoulders. A Tekscan pressure sensor placed between the repaired tuberosity and humerus recorded continuous data points directly after repair and for 60 min at set time intervals. The constructs were then cyclically loaded until 100 N, and the shoulders tested at 0°, 30°, and 60° of abduction. Under an applied force, the contact pressure and contact area of the interface were determined.

Results

Although both fixation configurations showed decreased contact pressure and area over time, the SB group had higher contact pressure right after fixation and at all time points thereafter. In contrast, the DR group demonstrated significantly more contact pressure and area at each abduction position with the applied load. Nevertheless, contact pressure and area decreased in response to increasing abduction position for both fixation constructs.

Conclusion

Findings suggest that despite the SB construct having superior interface contact immediately after fixation, the DR construct offered better contact performance at all abduction angles with applied force.

Level of evidence

Basic Science, Biomechanics.

Shoulder abduction diminishes self-reinforcement in transosseous-equivalent rotator cuff repair in both knotted and knotless techniques

PURPOSE

The self-reinforcement mechanism after double row suturebridge rotator cuff repair generates increasing compressive forces at the tendon footprint with increasing tendon load. Passive range of motion is usually allowed after rotator cuff repair. The mechanism of self-reinforcement could be adversely affected by shoulder abduction.

METHODS

Rotator cuff tears were created ex vivo in nine pairs of ovine shoulders. Two different repair techniques were used. One group was repaired using a double row 'suturebridge' construct with tied horizontal medial row mattress sutures (Knotted repair group). The other group was repaired identically except that medial row knots were not tied (Knotless repair group). Footprint compression was measured at varying amounts of abduction and under tendon loads of 0, 10, 20, 30, 40, 50 and 60N. The rate of increase of contact pressure (degree of self-reinforcement) was calculated for each abduction angle.

RESULTS

Abduction diminishes footprint contact pressure in both knotted and knotless double row suturebridge constructs. Progressive abduction from 0 to 40 abduction in the knotless group and 0-30 in the knotted group results in a decrease in self-reinforcement. Abduction beyond this does not cause a further decrease in self-reinforcement. There was no difference in the rate of increase of footprint contact pressure at each angle of abduction when comparing the knotted and knotless groups.

CONCLUSION

In the post-operative period, high tendon load combined with minimal abduction would be expected to generate the greatest amount of footprint compression which may improve tendon healing. Therefore, to maximize footprint compression the use of abduction pillows should be avoided while early isometric strengthening should be used.

Anterior Cable Reconstruction Using the Proximal Biceps Tendon for Large Rotator Cuff Defects Limits Superior Migration and Subacromial Contact Without Inhibiting Range of Motion: A Biomechanical Analysis

PURPOSE

To assess an anterior cable reconstruction (ACR) using autologous proximal biceps tendon for large to massive rotator cuff tears.

METHODS

Nine cadaveric shoulders (mean age, 58 years) were tested with a custom testing system. Range of motion, superior translation of the humeral head, and subacromial contact pressure were measured at 0°, 30°, 60°, and 90° of external rotation (ER) with 0°, 20°, and 40° of glenohumeral abduction. Five conditions were tested: intact, stage II tear (supraspinatus), stage II tear + ACR, stage III tear (supraspinatus + anterior half of infraspinatus), and stage III tear + ACR. ACR involved a biceps tendon tenotomy at the transverse humeral ligament, preserving its labral attachment. ACR included nonpenetrating suture-loop fixation using 2 side-to-side sutures and an anchor at the articular margin to restore anatomy and secure the tendon along the anterior edge of the cuff defect. ACR was performed in 20° glenohumeral abduction and 60° ER.

RESULTS

ACR for both stage II and stage III showed significantly higher total range of motion compared with intact at all angles (P ≤ .001). ACR significantly decreased superior translation for stage II tears at 0°, 30°, and 60° ER for both 0° and 20° abduction (P ≤ .01) and for stage III tears at 0° and 30° ER for both 0° and 20° abduction (P ≤ .004). ACR for stage III tear significantly reduced peak subacromial contact pressure at 30° and 60° ER with 0° and 40° abduction and at 30° ER with 20° abduction (P ≤ .041).

CONCLUSIONS

ACR using autologous biceps tendon biomechanically normalized superior migration and subacromial contact pressure, without limiting range of motion.

CLINICAL RELEVANCE

ACR may improve rotator cuff tendon repair longevity by providing basic static ligamentous support to the dynamic tendon while helping to limit superior migration without restricting glenohumeral kinematics.

Distal Triceps Speed Bridge Repair

Distal triceps ruptures are uncommon injuries resulting in loss of elbow extension strength and necessitating surgical repair to ensure optimal functional outcome. Traditional fixation techniques using running, locking sutures through the tendon secured through bone tunnels have been shown to poorly restore the anatomic footprint and are mechanically inferior to anatomic repairs. We endorse restoring the anatomic footprint of the distal triceps, similar to the well-researched rotator cuff repair model.

Effects of Abduction Pillows on Rotator Cuff Repair: A Biomechanical Analysis

BACKGROUND

After rotator cuff repair, some surgeons use abduction pillows to unload or protect the repair construct, while others do not.

QUESTION/PURPOSE

The aim of this study was to determine which type of sling-one with a small or large abduction pillow or one without a pillow-places the repaired rotator cuff in the best position to reduce tension on the supraspinatus.

METHODS

An X-ray study was performed on asymptomatic subjects to determine what position the shoulder is placed in when wearing a sling with or without an abduction pillow. Positions were then reproduced in human cadaveric shoulders using a custom-made testing jig, and tension on the repaired supraspinatus was measured.

RESULTS

X-rays showed that abduction of the glenohumeral joint with a sling was only 4°, with a sling with a small pillow was 13°, and with a sling with a large abduction pillow was 25°. Placing the cadaveric shoulders in the position of a sling with a small abduction pillow caused a reduction in tension on the supraspinatus of 27% anteriorly and 55% posteriorly compared to placing the shoulder in the position of a sling without an abduction pillow; a large abduction pillow caused a further reduction in tension, of 42% anteriorly and 56% posteriorly.

CONCLUSION

These findings show that abduction pillows reduce tension on the repaired supraspinatus tendon.

Superior Capsular Reconstruction

Superior capsular reconstruction (SCR) of the shoulder has recently gained popularity as an option for joint-preserving shoulder surgery for patients with an irreparable rotator cuff tear. In the absence of glenohumeral arthritis, rotator cuff tear irreparability should only be diagnosed for most patients after a careful diagnostic arthroscopy. Superior capsular reconstruction adds biological, passive, superior constraint to the glenohumeral joint, thereby optimizing the rotator cuff force couples and improving joint kinematics. At short-term follow-up, SCR has been shown to be effective for pain relief and restoration of active shoulder motion, even in the worst cases of shoulder dysfunction (true shoulder pseudoparalysis). The rapid early adoption and expansion of SCR is justified by its excellent anatomical, biomechanical, and short-term clinical results. The techniques for arthroscopic SCR using dermal allograft continue to improve; however, the operation remains technically demanding. Patients with risk factors for irreparability and who might benefit from reconstruction of the superior capsule should be counseled about the operation as an additional, joint-preserving procedure that can be done in conjunction with arthroscopic, partial rotator cuff repair. [Orthopedics. 2017; 40(5):271-280.].

Bridging suture makes consistent and secure fixation in double-row rotator cuff repair

BACKGROUND

Inconsistent tension distribution may decrease the biomechanical properties of the rotator cuff tendon after double-row repair, resulting in repair failure. The purpose of this study was to compare the tension distribution along the repaired rotator cuff tendon among three double-row repair techniques.

METHODS

In each of 42 fresh-frozen porcine shoulders, a simulated infraspinatus tendon tear was repaired by using 1 of 3 double-row techniques: (1) conventional double-row repair (no bridging suture); (2) transosseous-equivalent repair (bridging suture alone); and (3) compression double-row repair (which combined conventional double-row and bridging sutures). Each specimen underwent cyclic testing at a simulated shoulder abduction angle of 0° or 40° on a material-testing machine. Gap formation and tendon strain were measured during the 1st and 30th cycles. To evaluate tension distribution after cuff repair, difference in gap and tendon strain between the superior and inferior fixations was compared among three double-row techniques.

RESULTS

At an abduction angle of 0°, gap formation after either transosseous-equivalent or compression double-row repair was significantly less than that after conventional double-row repair (p < 0.01). During the 30th cycle, both transosseous-equivalent repair (p = 0.02) and compression double-row repair (p = 0.01) at 0° abduction had significantly less difference in gap formation between the superior and inferior fixations than did conventional double-row repair. After the 30th cycle, the difference in longitudinal strain between the superior and inferior fixations at 0° abduction was significantly less with compression double-row repair (2.7% ± 2.4%) than with conventional double-row repair (8.6% ± 5.5%, p = 0.03).

CONCLUSIONS

Bridging sutures facilitate consistent and secure fixation in double-row rotator cuff repairs, suggesting that bridging sutures may be beneficial for distributing tension equally among all sutures during double-row repair of rotator cuff tears.

Knotless Transosseous-Equivalent Rotator Cuff Repair Improves Biomechanical Self-reinforcement Without Diminishing Footprint Contact Compared With Medial Knotted Repair

PURPOSE

To assess the effect of medial-row knots on self-reinforcement and footprint contact characteristics for transosseous-equivalent repair compared with the same construct without knots.

METHODS

In 8 fresh-frozen human shoulders, transosseous-equivalent repairs with and without medial-row mattress knots were performed in each specimen. A pressure sensor was fixed at the tendon-footprint interface for all repairs. Parameters measured included footprint contact area, force, and pressure. The supraspinatus tendon was loaded sequentially from 0 to 60 N at 0° and 30° of abduction.

RESULTS

Both repairs provided a linear progression (slope) of footprint force and pressure as increasing tendon loads were applied. However, the knotless repair had a significantly higher progression ("self-reinforcement" effect) than the knotted repair at both abduction angles (P = .006 at 0° and P = .021 at 30°). The addition of medial-row knots did not significantly change the footprint contact area (in square millimeters), contact force (in newtons), contact pressure (in kilopascals), or peak pressure (in kilopascals) at each load tested, as well as at both abduction angles. For a given repair, only the knotless repair had significant decreases in contact area, contact force, contact pressure, and peak pressure with increasing abduction angles from 0° to 30° (P = .004 and P = .048).

CONCLUSIONS

Knotless transosseous-equivalent repair shows an improved self-reinforcement effect, without diminishing footprint contact, compared with the same repair with medial knots. Although knotless repair itself can show diminished footprint contact with abduction, medial knots show an adverse biomechanical effect by inhibiting self-reinforcement, without improving contact characteristics compared with knotless repair at each abduction angle tested. Clinical outcomes with specific indications, on the basis of these findings, require further investigation.

CLINICAL RELEVANCE

This study biomechanically helps to validate studies that have shown clinical success with knotless transosseous-equivalent repair. The inhibition of self-reinforcement may provide a quantified biomechanical rationale for medial tear patterns seen with knotted repairs.

Arthroscopic Double-Row Transosseous Equivalent Rotator Cuff Repair with a Knotless Self-Reinforcing Technique

BACKGROUND

Rotator cuff tears are a significant cause of shoulder morbidity. Surgical techniques for repair have evolved to optimize the biologic and mechanical variables critical to tendon healing. Double-row repairs have demonstrated superior biomechanical advantages to a single-row.

METHODS

The preferred technique for rotator cuff repair of the senior author was reviewed and described in a step by step fashion. The final construct is a knotless double row transosseous equivalent construct.

RESULTS

The described technique includes the advantages of a double-row construct while also offering self reinforcement, decreased risk of suture cut through, decreased risk of medial row overtensioning and tissue strangulation, improved vascularity, the efficiency of a knotless system, and no increased risk for subacromial impingement from the burden of suture knots.

CONCLUSION

Arthroscopic knotless double row rotator cuff repair is a safe and effective method to repair rotator cuff tears.

Triple-Loaded Single-Row Versus Suture-Bridge Double-Row Rotator Cuff Tendon Repair With Platelet-Rich Plasma Fibrin Membrane: A Randomized Controlled Trial

PURPOSE

To compare the structural healing and clinical outcomes of triple-loaded single-row with suture-bridging double-row repairs of full-thickness rotator cuff tendons when both repair constructs are augmented with platelet-rich plasma fibrin membrane.

METHODS

A prospective, randomized, consecutive series of patients diagnosed with full-thickness rotator cuff tears no greater than 3 cm in anteroposterior length were treated with a triple-loaded single-row (20) or suture-bridging double-row (20) repair augmented with platelet-rich plasma fibrin membrane. The primary outcome measure was cuff integrity by magnetic resonance imaging (MRI) at 12 months postoperatively. Secondary clinical outcome measures were American Shoulder and Elbow Surgeons, Rowe, Simple Shoulder Test, Constant, and Single Assessment Numeric Evaluation scores.

RESULTS

The mean MRI interval was 12.6 months (range, 12-17 months). A total of 3 of 20 single-row repairs and 3 of 20 double-row repairs (15%) had tears at follow-up MRI. The single-row group had re-tears in 1 single tendon repair and 2 double tendon repairs. All 3 tears failed at the original attachment site (Cho type 1). In the double-row group, re-tears were found in 3 double tendon repairs. All 3 tears failed medial to the medial row near the musculotendinous junction (Cho type 2). All clinical outcome measures were significantly improved from the preoperative level (P < .0001), but there was no statistical difference between groups postoperatively.

CONCLUSIONS

There is no MRI difference in rotator cuff tendon re-tear rate at 12 months postsurgery between a triple-loaded single-row repair or a suture-bridging double-row repair when both are augmented with platelet-rich plasma fibrin membrane. No difference could be demonstrated between these repairs on clinical outcome scores.

LEVEL OF EVIDENCE

I, Prospective randomized study.

Arthroscopic Knotless, Double-Row, Extended Linked Repair for Massive Rotator Cuff Tears

The management of massive rotator cuff tears remains a challenge for physicians, with failure rates being higher when compared with smaller tears. Many surgical treatment options exist including debridement with biceps tenodesis, complete repair, partial repair, repair with augmentation devices, superior capsule reconstruction, tendon transfer, and reverse total shoulder arthroplasty. The purpose of this article is to describe our preferred surgical technique for a complete arthroscopic repair using an extended linked, knotless, double-row construct.

The optimum tension for bridging sutures in transosseous-equivalent rotator cuff repair: a cadaveric biomechanical study

BACKGROUND

Transosseous-equivalent (TOE) rotator cuff repair can increase contact area and contact pressure between the repaired cuff tendon and bony footprint and can show higher ultimate loads to failure and smaller gap formation compared with other repair techniques. However, it has been suggested that medial rotator cuff failure after TOE repair may result from increased bridging suture tension.

PURPOSE

To determine optimum bridging suture tension in TOE repair by evaluating footprint contact and construct failure characteristics at different tensions.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 18 fresh-frozen cadaveric shoulders, randomly divided into 3 groups, were constructed with a TOE configuration using the same medial suture anchor and placing a Tekscan sensing pad between the repaired rotator cuff tendon and footprint. Nine of the 18 shoulders were used to measure footprint contact characteristics. With use of the Tekscan measurement system, the contact pressure and area between the rotator cuff tendon and greater tuberosity were quantified for bridging suture tensions of 60, 90, and 120 N with glenohumeral abduction angles of 0° and 30° and humeral rotation angles of 30° (internal), 0°, and 30° (external). TOE constructs of all 18 shoulders then underwent construct failure testing (cyclic loading and load to failure) to determine the yield load, ultimate load, stiffness, hysteresis, strain, and failure mode at 60 and 120 N of tension.

RESULTS

As bridging suture tension increased, contact force, contact pressure, and peak pressure increased significantly at all positions (P < .05 for all). Regarding contact area, no significant differences were found between 90 and 120 N at all positions, although there were significant differences between 60 and 90 N. The construct failure test demonstrated no significant differences in any parameters according to various tensions (P > .05 for all).

CONCLUSION

Increasing bridging suture tension to over 90 N did not improve contact area but did increase contact force and pressure. Bridging suture tension did not significantly affect ultimate failure loads.

CLINICAL RELEVANCE

Considering the risks of overtensioning bridging sutures, it may be clinically more beneficial to keep bridging suture tension below 90 N.

Does transosseous-equivalent rotator cuff repair biomechanically provide a "self-reinforcement" effect compared with single-row repair?

BACKGROUND

Transosseous-equivalent (TOE) rotator cuff repair has been theorized to be "self-reinforcing" against potentially destructive and increasing tendon loads. The goal of this study was to biomechanically verify and characterize the effect of increasing tendon load on frictional resistance over a repaired footprint for single-row (SR) and TOE repair techniques.

METHODS

In 10 fresh frozen human shoulders, TOE and SR supraspinatus tendon repairs were performed in each specimen. For all repairs, a pressure sensor was secured at the tendon-footprint interface. The supraspinatus tendon was loaded with 0, 20, 40, 60, and 80 N at 0° and 30° abduction. Paired t tests and multivariate regression analyses were used for comparisons.

RESULTS

The SR repair had significant increases in footprint contact force, area, and pressure between each and all tendon-loading conditions (P < .05). The TOE repair similarly demonstrated increases in footprint contact force with increasing tendon load (P < .05). Comparing between repairs, TOE repair had more footprint contact force, area, pressure, and peak pressure at each load for both abduction angles (P < .05). With increasing load, the TOE repair had a significantly higher progression (slope) of footprint force and pressure compared with the SR repair.

CONCLUSIONS

Self-reinforcing capacity in rotator cuff repair has been biomechanically characterized and verified. The TOE repair, with tendon-bridging sutures fixed medially and spanning the footprint, provides disproportionately more progressive footprint frictional resistance with increasing tendon loads compared with the SR repair secured over isolated fixation points. This self-reinforcing effect could help sustain structural integrity and potentially improve healing biology.

The biomechanical effects of polytetrafluoroethylene suture augmentations in lateral-row rotator cuff repairs in an ovine model

BACKGROUND

This study investigated the biomechanical effects of expanded polytetrafluoroethylene (ePTFE) suture augmentation patches in rotator cuff repair constructs.

METHODS

The infraspinatus tendon in 24 cadaveric ovine shoulders was repaired using an inverted horizontal mattress suture with 2 knotless bone anchors (ArthroCare, Austin, TX, USA) in a lateral-row configuration. Four different repair groups (6 per group) were created: (1) standard repair using inverted horizontal mattress sutures, (2) repair with ePTFE suture augmentations on the bursal side of the tendon, (3) repair with ePTFE suture augmentations on the articular side, and, (4) repair with ePTFE suture augmentations on both sides of the tendon. Footprint contact pressure, stiffness, and the load to failure of the repair constructs were measured.

RESULTS

Repairs with ePTFE suture augmentations on the bursal side exerted significantly more footprint contact pressure (0.40 ± 0.01 MPa) than those on the articular side (0.34 ± 0.02 MPa, P = .04) and those on both sides (0.33 ± 0.02 MPa, P = .01). At 15 degrees of abduction, ePTFE-augmented repairs on the bursal side had higher footprint contact pressure (0.26 ± 0.03 MPa) compared with standard repairs (0.15 ± 0.02 MPa, P = .01) and with ePTFE-augmented repairs on the articular side (0.18 ± 0.02 MPa, P = .03). The ePTFE-augmented repairs on the bursal side demonstrated significantly higher failure loads (178 ± 18 N) than standard repairs (120 ± 17 N, P = .04).

CONCLUSIONS

Inverted horizontal mattress sutures augmented with ePTFE patches on the bursal side of the tendon enhanced footprint contact pressures and the ultimate load to failure of lateral-row rotator cuff repairs in an ovine model.

Biomechanical effects of a 2 suture-pass medial inter-implant mattress on transosseous-equivalent rotator cuff repair and considerations for a "technical efficiency ratio"

BACKGROUND

Rotator cuff repair involving fewer tendon suture passes without compromising biomechanical performance would represent a technical advancement. An inter-implant "medial pulley-mattress" transosseous-equivalent (MP-TOE) repair requiring fewer tendon suture-passes was hypothesized to provide equivalent biomechanical characteristics compared to the control.

METHODS

In 6 human cadaveric shoulders, a transosseous-equivalent (TOE) repair (control) was performed utilizing 2 separate medial mattresses resulting in 4 tendon-bridging sutures. In 6 matched-pairs, 2 single-loaded anchors were used to create a medial inter-implant mattress construct (all sutures shuttled in 1 tendon pass per anchor)-after knot-tying, the same tendon-bridging pattern as the control was created. A materials testing machine cyclically loaded each repair from 10-180 N for 30 cycles; each repair subsequently underwent failure testing. Gap and strain were measured with a video digitizing system. A "technical efficiency ratio" (TER) was defined as: (#knots + #suture passes + #suture limbs)/#fixation points.

RESULTS

Cyclic and failure testing demonstrated no significant differences between constructs. Gap formation at cycle 30 was 5.3 ± 0.8 mm (TOE) and 5.0 ± 0.3 mm (MP-TOE) (P = .62). Cycle 30 anterior strain values were -16.0 ± 7.3% (TOE) and -15.8 ± 6.6% (MP-TOE) (P = .99). Yield loads were 208.7 ± 2.7 N (TOE) and 204.0 ± 1.3 N (MP-TOE) (P = .17). Mode of failure demonstrated less tendon cut-out with the MP-TOE repair. The MP-TOE repair has a TER of 2.0 vs 2.5 for the control.

CONCLUSION

The MP-TOE repair requiring fewer tendon suture passes, yet creating an additional inter-implant mattress configuration, is biomechanically equivalent to the original TOE technique, and may limit failure with improved medial load-sharing capacity. A TER may help quantify technical ease and help standardize comparisons between repair techniques.

Biomechanical characteristics of the horizontal mattress stitch: implication for double-row and suture-bridge rotator cuff repair

BACKGROUND

We investigated the effects of bite-size horizontal mattress stitch (distance between the limbs passed through the tendon) on the biomechanical properties of the repaired tendon.

METHODS

We anchored 20 bovine Achilles tendons to bone using no. 2 high-strength suture and 5-mm titanium suture anchors in a mattress-suture technique. Tendons were allocated randomly into two groups of ten each to receive stitches with a 4- or 10-mm bite. Specimens underwent cyclic loading from 5 to 30 N at 1 mm/s for 30 cycles, followed by tensile testing to failure. Gap formation, tendon strain, hysteresis, stiffness, yield load, ultimate load, energy to yield load, and energy to ultimate load were compared between groups using unpaired t tests.

RESULTS

The 4-mm group had less (p < 0.05) gap formation and less (p < 0.05) longitudinal strain than did the 10-mm group. Ultimate load (293.6 vs. 148.9 N) and energy to ultimate load (2,563 vs. 1,472 N-mm) were greater (p < 0.001) for the 10-mm group than the 4-mm group. All tendons repaired with 4-mm suturing failed at the suture-tendon interface, with sutures pulling through the tendon, whereas the suture itself failed before the tendon did in seven of the ten specimens in the 10-mm group.

CONCLUSIONS

Whereas a 4-mm bite fixed the tendon more tightly but at the cost of decreased ultimate strength, a 10-mm bite conveyed greater ultimate strength but with increased gap and strain. These results suggest that for the conventional double-row repair, small mattress stitches provide a tighter repair, whereas large stitches are beneficial to prevent sutures from pulling through the tendon after surgery. For suture-bridge rotator cuff repair, large stitches are beneficial because the repaired tendon has a higher strength, and the slightly mobile medial knot can be tightened by lateral fixation.

Clinical comparison between double-row and transosseous-equivalent repairs for medium to large size rotator cuff tears

BACKGROUND

The transosseous-equivalent (TOE) repair of the rotator cuff tears was invented to make up for several shortcomings of the double-row (DR) repair. However, no studies have compared the clinical aspects of the DR repair and the TOE technique, supporting the superior results of the TOE technique over the DR repair, including the benefit of minimizing surgical steps. We asked whether differences existed between the two repairs regarding clinical outcomes, time and costs.

MATERIALS AND METHODS

Subjects included 55 using the DR repair and 119 using the TOE repair for the medium to large sized rotator cuff tears. Clinical outcomes were measured with a Visual Analog Scale, American Shoulder and Elbow Surgeons score, Constant score, and shoulder strength. For practical aspects, operative time and number of suture anchors used for the medial and lateral rows were compared.

RESULTS

Both repairs brought substantial improvements in pain and function. However, significant differences were not detected between the repairs in all the clinical measurements. Regarding operative time and costs, in the medium size tears, a statistical difference was found only in the anchors used for the lateral row. In the large size tears, the DR repair required more operation time than the TOE repair, while the TOE repair used more anchors for the lateral row.

CONCLUSION

This study failed to demonstrate clinical differences between the techniques. However, when stratifying rotator cuff tears according to the tear sizes, significant differences were found in operative time and cost: the DR repair had the advantage of cost effectiveness by saving anchors for the lateral row, while the TOE repair required less operative time with more anchors used for the lateral row in the large size tears. This finding provides evidence to support the use of the TOE repair to reduce surgical steps.

An in-vitro study of rotator cuff tear and repair kinematics using single- and double-row suture anchor fixation

Purpose:

Double-row suture anchor fixation of the rotator cuff was developed to reduce repair failure rates. The purpose of this study was to determine the effects of simulated rotator cuff tears and subsequent repairs using single- and double-row suture anchor fixation on three-dimensional shoulder kinematics. It was hypothesized that both single- and double-row repairs would be effective in restoring active intact kinematics of the shoulder.

Materials and Methods:

Sixteen fresh-frozen cadaveric shoulder specimens (eight matched pairs) were tested using a custom loading apparatus designed to simulate unconstrained motion of the shoulder. In each specimen, the rotator cuff was sectioned to create a medium-sized (2 cm) tear. Within each pair, one specimen was randomized to a single-row suture anchor repair, while the contralateral side underwent a double-row suture anchor repair. Joint kinematics were recorded for intact, torn, and repaired scenarios using an electromagnetic tracking device.

Results:

Active kinematics confirmed that a medium-sized rotator cuff tear affected glenohumeral kinematics when compared to the intact state. Single- and double-row suture anchor repairs restored the kinematics of the intact specimen.

Conclusions:

This study illustrates the effects of medium-sized rotator cuff tears and their repairs on active glenohumeral kinematics. No significant difference (P ≥ 0.10) was found between the kinematics of single- and double-row techniques in medium-sized rotator cuff repairs.

Clinical Relevance:

Determining the relative effects of single- and double-row suture anchor repairs of the rotator cuff will allow physicians to be better equipped to treat patients with rotator cuff disease.

Optimal shoulder immobilization postures following surgical repair of rotator cuff tears: a simulation analysis

BACKGROUND

There is a high incidence of retear following surgical repair of rotator cuff tears. Postoperative shoulder immobilization is commonly prescribed to protect the repair; but there is no consensus on the best immobilization postures.

METHODS

A generic musculoskeletal model of the shoulder was used to simulate postoperative immobilization of full thickness rotator cuff tears involving the supraspinatus only and the supraspinatus concomitantly with the infraspinatus or subscapularis. Optimal immobilization postures, which simultaneously minimized the stresses in the repaired tendons and the angle of humerus elevation, were obtained.

RESULTS

For isolated supraspinatus tears, elevation of the humerus in planes close to the scapular plane was suggested. When the infraspinatus was also involved, planes posterior to the scapular plane were suggested; while, if the subscapularis was also involved, planes anterior to the scapular plane and internal rotation were suggested. The required thoracohumeral elevation angles ranged from 58° to 109°, depending on the tear length and the muscles involved. The optimal postures reduced the stresses in the repaired tendons by between 29% and 90%.

CONCLUSION

Prescription of immobilization posture for a patient should be based on the conditions of the tear repaired. Appropriate choice of immobilization posture will reduce the stress in the repair, and as such has the potential to reduce retear rates.

Biomechanical comparison of single-row, double-row, and transosseous-equivalent repair techniques after healing in an animal rotator cuff tear model

The transosseous-equivalent (TOE) rotator cuff repair technique increases failure loads and contact pressure and area between tendon and bone compared to single-row (SR) and double-row (DR) repairs, but no study has investigated if this translates into improved healing in vivo. We hypothesized that a TOE repair in a rabbit chronic rotator cuff tear model would demonstrate a better biomechanical profile than SR and DR repairs after 12 weeks of healing. A two-stage surgical procedure was performed on 21 New Zealand White Rabbits. The right subscapularis tendon was transected and allowed to retract for 6 weeks to simulate a chronic tear. Repair was done with the SR, DR, or TOE technique and allowed to heal for 12 weeks. Cyclic loading and load to failure biomechanical testing was then performed. The TOE repair showed greater biomechanical characteristics than DR, which in turn were greater than SR. These included yield load (p < 0.05), energy absorbed to yield (p < 0.05), and ultimate load (p < 0.05). For repair of a chronic, retracted rotator cuff tear, the TOE technique was the strongest biomechanical construct after healing followed by DR with SR being the weakest.

Biomechanical validation of rotator cuff repair techniques and considerations for a "technical efficiency ratio"

Biomechanical studies are commonly used to validate new or modified rotator cuff repair techniques. Additional knots, more tendon suture passes, and obligatory suture management requirements are often the "cost" for improved biomechanical results. This cost can amount to increased technical difficulty and surgical times. However, technical ease or difficulty as a measurable variable has not been quantified. A basic measure for technical ease would allow surgeons the ability to objectively assess and compare rotator cuff repair practicality and potentially help in the design of future studies to standardize repair techniques alongside biomechanical measures. A proposed rotator cuff repair "technical efficiency ratio" is defined as follows: (No. of knots + No. of tendon suture passes + No. of suture limbs)/No. of pilot holes created. This can give a measure of "work" or utility achieved per fixation point created for a particular type of repair (e.g., single or double row), with a smaller number representing relatively more efficiency per anchor or fixation point used. If repairs validated in the laboratory are too cumbersome to perform in vivo from a practical standpoint, technical ease should be a prerequisite measure, and the success of a repair technique should not necessarily be based on biomechanics alone.

Rotator cuff tendon repair morphology comparing 2 single-anchor repair techniques

PURPOSE

To compare the effect of 2 common rotator cuff repair techniques, for smaller tears limited to the use of a single anchor, on tendon morphology in relation to the footprint.

METHODS

Six matched pairs of human shoulders were dissected, and a standardized 10-mm supraspinatus tendon tear was created. Two single-anchor repairs were performed: simple repair with the anchor on the footprint or inverted-mattress repair with the anchor 1 cm distal-lateral to the footprint. The repaired specimens were frozen in situ with liquid nitrogen. Coronal cross sections through the intact and repaired tendon were made. A digitizer was used to measure variables including tendon area and radius of tendon curvature.

RESULTS

Comparing between repairs, we found significantly more gap formation for the simple repair at the repair cross section (3.67 ± 0.32 mm v 0.68 ± 0.10 mm, P = .00050). The simple repair had less tendon area (38.28 ± 2.50 mm(2)v 58.65 ± 4.06 mm(2), P = .0036) and a smaller radius of curvature (8.47 ± 1.39 mm v 32.51 ± 3.94 mm, P = .0046). For the simple repair, there was significantly more gap formation, less tendon area, and a smaller radius of tendon curvature for all repair cross sections compared with the intact cross sections (P < .05). For the inverted-mattress repair, there was more gap formation compared with the intact condition (P < .05), although it was less than 1 mm on average; for tendon area, radius of curvature, and tendon height, the cross section centered on the repair showed no differences compared with the intact control.

CONCLUSIONS

For rotator cuff tears that are 10 mm or smaller and limited to the use of a single anchor, using a distal-lateral anchor position with tape-type suture can provide better maintenance of native tendon morphology and footprint dimensions when compared with repair that uses standard sutures and places the anchor on the footprint.

CLINICAL RELEVANCE

For smaller tears, the inverted-mattress repair described in this article may provide a relatively improved healing environment compared with a simple repair on the footprint, potentially optimizing the prevention of early tear progression.

Arthroscopic refixation of a combined fracture of the greater and lesser tuberosity of the proximal humerus

Combined fractures of the greater and the lesser tuberosity are very rare injuries. This is a case report on arthroscopic treatment using suture anchors and one distal fixation screw. Clinical and radiographic follow-up showed recovery of active motion and consolidation of the fragments in anatomic positions.

LEVEL OF EVIDENCE

V.

Biomechanical evaluation of transosseous rotator cuff repair: do anchors really matter?

BACKGROUND

Suture anchor fixation has become the preferred method for arthroscopic repairs of rotator cuff tears. Recently, newer arthroscopic repair techniques including transosseous-equivalent repairs with anchors or arthroscopic transosseous suture passage have been developed.

PURPOSE

To compare the initial biomechanical performance including ultimate load to failure and localized cyclic elongation between transosseous-equivalent repair with anchors (TOE), traditional transosseous repair with a curved bone tunnel (TO), and an arthroscopic transosseous repair technique utilizing a simple (AT) or X-box suture configuration (ATX).

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty-eight human cadaveric shoulders were dissected to create an isolated supraspinatus tear and randomized into 1 of 4 repair groups (TOE, TO, AT, ATX). Tensile testing was conducted to simulate the anatomic position of the supraspinatus with the arm in 60° of abduction and involved an initial preload, cyclic loading, and pull to failure. Localized elongation during testing was measured using optical tracking. Data were statistically assessed using analysis of variance with a Tukey post hoc test for multiple comparisons.

RESULTS

The TOE repair demonstrated a significantly higher mean ± SD failure load (558.4 ± 122.9 N) compared with the TO (325.3 ± 79.9 N), AT (291.7 ± 57.9 N), and ATX (388.5 ± 92.6 N) repairs (P < .05). There was also a significantly larger amount of first-cycle excursion in the AT group (8.19 ± 1.85 mm) compared with the TOE group (5.10 ± 0.89 mm). There was no significant difference between repair groups in stiffness during maximum load to failure or in normalized cyclic elongation. Failure modes were as follows: TOE, tendon (n = 4) and bone (n = 3); TO, suture (n = 6) and bone (n = 1); AT, tendon (n = 2) and bone (n = 3) and suture (n = 1); ATX, tendon (n = 7).

CONCLUSION

This study demonstrates that anchorless repair techniques using transosseous sutures result in significantly lower failure loads than a repair model utilizing anchors in a TOE construct.

CLINICAL RELEVANCE

Suture anchor repair appears to offer superior biomechanical properties to transosseous repairs regardless of tunnel or suture configuration.

The failure mode of two reabsorbable fixation systems: Swivelock with Fibertape versus Bio-Corkscrew with Fiberwire in bovine rotator cuff

BACKGROUND

Despite technical advances in rotator cuff surgery, recurrent or persistent defects in the repaired tendon continue to occur. The improved strength of sutures and suture anchors has shown that the most common site of failure is the suture-tendon interface. The purpose of this study was to compare two different types of repair under both cyclic and load-to-failure conditions. The hypothesis is that the use of a fixation system with knotless anchor and taped suture results in better biomechanical performance, under both cyclic and load-to-failure conditions.

METHODS

Thirty bovine shoulder specimens were randomly assigned to two group tests: the Swivelock 5-mm anchor with Fibertape (Group A) and the Bio-Corkscrew 5 mm with Fiberwire (Group B). We simulated the reconstruction of a rotator cuff tear with a single-row technique, performing a tenodesis with types A and B fixation. Each specimen underwent cyclic testing from 5 to 30 N for 30 cycles, followed by load-to-failure testing, in order to calculate the ultimate failure load (UFL).

RESULTS

Load-to-failure tests revealed a significantly higher UFL in Group A than in Group B. Wire fixing failed at the anchor loop whereas tape fixing failed at the sutures, suture-tendon interface, and anchors. Cyclic testing revealed no significantly greater slippage between the two groups. Stiffness values were not statistically significantly different. In all cases, tendons remained intact until the end of the cyclic testing.

CONCLUSIONS

The tape structure is biomechanically stronger than the wire structure.

A new technique of arthroscopic fixation using double anchors for SLAP lesions

PURPOSE

The aim of this study was to evaluate the clinical and structural outcome of the new fixation technique of type-II SLAP repair using double anchors compared with conventional method.

METHODS

Twenty-eight patients with 29 shoulders, who were followed up for at least 1 year after surgery, were enrolled. Fourteen shoulders were treated using the new technique (group 1), and 15 shoulders using the conventional technique (group 2). The clinical outcomes were evaluated using two different functional scores, the pain VAS and range of motion. The postoperative labral integrity was determined by magnetic resonance imaging at 1 year after surgery.

RESULTS

At postoperative 6 months, all functional scores of group 1 were superior to group 2, particularly in pain VAS and Constant Scoring System. All ranges of motion in group 1 showed a better result than in group 2, particularly in forward flexion and external rotation at 90° abduction (88° ± 4.8 in group 1 and 84° ± 9.2 in group 2, P = 0.03). At postoperative 12 months and the last visit, all functional scores in group 1 were superior to those in group 2 and all external rotations at 90° of abduction in group 1 showed significantly better results than those of group 2. All patients in group 1 showed complete healing of the repaired SLAP lesion but one patient in group 2 showed partial detachments on the MRI.

CONCLUSIONS

This new technique provides anatomical restoration of a SLAP lesion and yields successful clinical and structural outcomes at a short-term follow-up.

LEVEL OF EVIDENCE

Randomized controlled trials, level II.

A biomechanical comparison of tendon-bone interface motion and cyclic loading between single-row, triple-loaded cuff repairs and double-row, suture-tape cuff repairs using biocomposite anchors

PURPOSE

To compare tendon-bone interface motion and cyclic loading in a single-row, triple-loaded anchor repair with a suture-tape, rip-stop, double-row rotator cuff repair.

METHODS

Using 18 human shoulders from 9 matched cadaveric pairs, we created 2 groups of rotator cuff repairs. Group 1 was a double-row, rip-stop, suture-tape construct. Group 2 was a single-row, triple-loaded construct. Before mechanical testing, the supraspinatus footprint was measured with calipers. A superiorly positioned digital camera optically measured the tendon footprint motion during 60° of humeral internal and external rotation. Specimens were secured at a fixed angle not exceeding 45° in reference to the load. After preloading, each sample was cycled between 10 N and 100 N for 200 cycles at 1 Hz, followed by destructive testing at 33 mm/s. A digital camera with tracking software measured the repair displacement at 100 and 200 cycles. Ultimate load and failure mode for each sample were recorded.

RESULTS

The exposed anterior footprint border (6.5% ± 6%) and posterior footprint border (0.9% ± 1.7%) in group 1 were statistically less than the exposed anterior footprint border (30.3% ± 17%) and posterior footprint border (29.8% ± 14%) in group 2 (P = .003 and P < .001, respectively). The maximal internal rotation and external rotation tendon footprint displacements in group 1 (1.6 mm and 1.4 mm, respectively) were less than those in group 2 (both 3.6 mm) (P = .007 and P = .004, respectively). Mean displacement after 100 cycles for group 1 and group 2 was 2.0 mm and 3.2 mm, respectively, and at 200 cycles, mean displacement was 2.5 mm and 4.2 mm, respectively (P = .02). The mean ultimate failure load in group 1 (586 N) was greater than that in group 2 (393 N) (P = .02). The suture-tendon interface was the site of most construct failures.

CONCLUSIONS

The suture-tape, rip-stop, double-row rotator cuff repair had greater footprint coverage, less rotational footprint displacement, and a greater mean ultimate failure load than the triple-loaded, single-row repair on mechanical testing. No double-row or single-row constructs showed 5 mm of displacement after the first 100 cycles. The most common failure mode for both constructs was suture tearing through the tendon.

CLINICAL RELEVANCE

Differences in cuff fixation influence rotational tendon movement and may influence postoperative healing. Stronger repair constructs still fail at the suture-tendon interface.

A watertight construct in arthroscopic rotator cuff repair

BACKGROUND

It is unknown which type of rotator cuff repair technique best isolates the healing zone interface from the synovial fluid environment. The purpose of this study was to determine the leakage area and pattern onto the rotator cuff footprint after 3 different rotator cuff repairs.

MATERIALS AND METHODS

Six fresh frozen cadaveric glenohumeral joints in each of 3 groups were injected with gelatin to a pressure of 103 mm Hg (∼2 psi) after 1 of 3 different rotator cuff repairs of a supraspinatus tear: (1) single-row repair (SR), (2) knotless transosseous equivalent repair (KTE), and (3) traditional transosseous equivalent repair (TTE), which uses medial tied knots. Specimens were cycled in external rotation and abduction and were cooled to allow the gelatin to solidify. The supraspinatus was dissected off the footprint and photographs were taken. Scion Image (Frederick, MD, USA) was used to quantify the area.

RESULTS

The average area of leakage was 1.09 cm(2) for the SR and 1.15 cm(2) for the KTE. The TTE did not demonstrate any leakage. The pattern of leakage for the KTE was medial and central on the footprint, whereas the SR demonstrated leakage up to the tied knots. The difference in the area of leakage in the SR and KTE compared with the TTE was statistically significant. There was no difference in area of leakage between the SR and KTE.

CONCLUSION

A transosseous equivalent repair technique best prevents leakage onto the rotator cuff footprint compared with single-row and knotless repairs.

Functional and structural outcomes of single-row versus double-row versus combined double-row and suture-bridge repair for rotator cuff tears

BACKGROUND

Although previous biomechanical research has demonstrated the superiority of the suture-bridge rotator cuff repair over double-row repair from a mechanical point of view, no articles have described the structural and functional outcomes of this type of procedure.

HYPOTHESIS

The structural and functional outcomes after arthroscopic rotator cuff repair may be different between the single-row, double-row, and combined double-row and suture-bridge (compression double-row) techniques.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

There were 206 shoulders in 201 patients with full-thickness rotator cuff tears that underwent arthroscopic rotator cuff repair. Eleven patients were lost to follow-up. Sixty-five shoulders were repaired using the single-row, 23 shoulders using the double-row, and 107 shoulders using the compression double-row techniques. Clinical outcomes were evaluated at an average of 38.5 months (range, 24-74 months) after rotator cuff repair. Postoperative cuff integrity was determined using Sugaya's classification of magnetic resonance imaging (MRI).

RESULTS

The retear rates after arthroscopic rotator cuff repair were 10.8%, 26.1%, and 4.7%, respectively, for the single-row, double-row, and compression double-row techniques. In the subcategory of large and massive rotator cuff tears, the retear rate in the compression double-row group (3 of 40 shoulders, 7.5%) was significantly less than those in the single-row group (5 of 8 shoulders, 62.5%, P < .001) and the double-row group (5 of 12 shoulders, 41.7%, P < .01). Postoperative clinical outcomes in patients with a retear were significantly lower than those in patients without a retear for all 3 techniques.

CONCLUSION

The additional suture bridges decreased the retear rate for large and massive tears. The combination of the double-row and suture-bridge techniques, which had the lowest rate of postoperative retear, is an effective option for arthroscopic repair of the rotator cuff tendons because the postoperative functional outcome in patients with a retear is inferior to that without retear.

Effect of shoulder abduction angle on biomechanical properties of the repaired rotator cuff tendons with 3 types of double-row technique

BACKGROUND

After rotator cuff repair, the shoulder is immobilized in various abduction positions. However, there is no consensus on the proper abduction angle.

PURPOSE

To assess the effect of shoulder abduction angle on the biomechanical properties of the repaired rotator cuff tendons among 3 types of double-row techniques.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-two fresh-frozen porcine shoulders were used. A simulated rotator cuff tear was repaired by 1 of 3 double-row techniques: conventional double-row repair, transosseous-equivalent repair, and a combination of conventional double-row and bridging sutures (compression double-row repair). Each specimen underwent cyclic testing followed by tensile testing to failure at a simulated shoulder abduction angle of 0° or 40° on a material testing machine. Gap formation and failure loads were measured.

RESULTS

Gap formation in conventional double-row repair at 0° (1.2 ± 0.5 mm) was significantly greater than that at 40° (0.5 ± 0.3mm, P = .01). The yield and ultimate failure loads for conventional double-row repair at 40° were significantly larger than those at 0° (P < .01), whereas those for transosseous-equivalent repair (P < .01) and compression double-row repair (P < .0001) at 0° were significantly larger than those at 40°. The failure load for compression double-row repair was the greatest among the 3 double-row techniques at both 0° and 40° of abduction.

CONCLUSION

Bridging sutures have a greater effect on the biomechanical properties of the repaired rotator cuff tendon at a low abduction angle, and the conventional double-row technique has a greater effect at a high abduction angle.

CLINICAL RELEVANCE

Proper abduction position after rotator cuff repair differs between conventional double-row repair and transosseous-equivalent repair. The authors recommend the use of the combined technique of conventional double-row and bridging sutures to obtain better biomechanical properties at both low and high abduction angles.

Single versus double-row repair of the rotator cuff: does double-row repair with improved anatomical and biomechanical characteristics lead to better clinical outcome?

PURPOSE

Several techniques for arthroscopic repair of rotator cuff defects have been introduced over the past years. Besides established techniques such as single-row repairs, new techniques such as double-row reconstructions have gained increasing interest. The present article therefore provides an overview of the currently available literature on both repair techniques with respect to several anatomical, biomechanical, clinical and structural endpoints.

METHODS

Systematic literature review of biomechanical, clinical and radiographic studies investigating or comparing single- and double-row techniques. These results were evaluated and compared to provide an overview on benefits and drawbacks of the respective repair type.

RESULTS

Reconstructions of the tendon-to-bone unit for full-thickness tears in either single- or double-row technique differ with respect to several endpoints. Double-row repair techniques provide more anatomical reconstructions of the footprint and superior initial biomechanical characteristics when compared to single-row repair. With regard to clinical results, no significant differences were found while radiological data suggest a better structural tendon integrity following double-row fixation.

CONCLUSION

Presently published clinical studies cannot emphasize a clearly superior technique at this time. Available biomechanical studies are in favour of double-row repair. Radiographic studies suggest a beneficial effect of double-row reconstruction on structural integrity of the reattached tendon or reduced recurrent defect rates, respectively.

Tension, abduction, and surgical technique affect footprint compression after rotator cuff repair in an ovine model

INTRODUCTION

Shoulder motion after rotator cuff repair may result in changes in tension and contact pressure at the repair site. Our goal was to determine how tension and motion affect a repair and what type of repair best tolerates these variables.

METHODS

Rotator cuff tears were created ex vivo in 30 ovine shoulders divided into 5 groups: single-row repair, double-row repair, tension-band repair, suture bridge repair, and double-row tension-band repair. A pressure probe was passed through a hole created in the footprint to dynamically measure footprint pressure. The rotator cuffs were repaired, and contact pressure was measured with variable tension placed on the repaired tendon from 10 to 30 N and variable shoulder abduction from -10° to +10°. Repair strength was determined by use of a pull-to-failure test.

RESULTS

Increasing tension on the repaired tendon resulted in an increase in contact pressure whereas increasing the abduction angle resulted in a decrease in contact pressure in all 5 groups. For all abduction and tension combinations, the suture-bridge and double-row tension band groups recorded the highest contact pressures (P < .05), followed by the tension-band, single-row, and double-row repairs. Load to failure was greatest for the 2 double-row techniques, followed by the tension-band, suture-bridge, and single-row repairs.

DISCUSSION

Contact pressure increases as tension increases across the repair and decreases as the shoulder is abducted. The double-row tension-band rotator cuff repair showed the best combination of contact pressure and repair strength.

Repair of partial-thickness rotator cuff tears: a biomechanical analysis of footprint contact pressure and strength in an ovine model

PURPOSE

The purpose of this study was to determine whether transtendon repair by use of a novel small-diameter knotless anchor showed enhanced mechanical properties compared with tear completion and repair.

METHODS

Articular-sided partial-thickness tears were created ex vivo in the infraspinatus of 24 ovine shoulders. The specimens were randomized into 4 groups of 6 each: (1) no repair, (2) transtendon repair, (3) completion of tear with tension-band single-row repair, and (4) completion of tear with double-row repair. Footprint contact pressure and ultimate load to failure were measured in each specimen.

RESULTS

Technical failure of the transtendon anchors occurred in 3 of 15 shoulders. Transtendon repair (mean +/- SEM, 0.8 +/- 0.1 MPa) and double-row repair (1 +/- 0.09 MPa) showed 3-fold (P < .001) greater footprint contact pressures than tension-band single-row repair (0.3 +/- 0.03 MPa) and no repair (0.3 +/- 0.02 MPa). The ultimate load to failure for transtendon repair (544 +/- 22 N) was more than 3 times greater than that for the double-row repair (157 +/- 23 N) (P < .001) and the single-row repair (116 +/- 11 N) (P < .001).

CONCLUSIONS

Transtendon repair of partial-thickness tears by use of specifically designed anchors biomechanically outperformed tear completion and repair in an ovine model. Transtendon repair showed the best combination of high footprint contact pressure and high ultimate failure load. However, the high insertion failure rate of these transtendon anchors is of concern.

CLINICAL RELEVANCE

On the basis of the biomechanical data, transtendon repair of partial-thickness rotator cuff tears may be used as an alternative to tear completion and repair, but the specific transtendon anchors used in this study need further evaluation before their clinical use can be recommended.