Biomechanical evaluation of arthroscopic rotator cuff stitches

BACKGROUND: The suture configurations in arthroscopic rotator cuff repairs have been limited to simple and horizontal stitches. Recent objective evaluations have demonstrated high failure rates of arthroscopic repairs of rotator cuff tears. A novel stitch for arthroscopic repair of the rotator cuff, the massive cuff stitch, was developed to increase the strength of the suture-tendon interface. The goal of this study was to determine the biomechanical properties of the massive cuff stitch and to compare it with other stitches commonly used for rotator cuff repair. METHODS: Eight pairs of sheep infraspinatus tendons were harvested and split in half to yield a set of four tendon specimens from each animal. Four stitch configurations (simple, horizontal, massive cuff, and modified Mason-Allen) were randomized and biomechanically tested in each set of tendon specimens. Each specimen was first cyclically loaded on an MTS uniaxial load frame under force control from 5 to 30 N at 0.25 Hz for twenty cycles. Each specimen was then loaded to failure under displacement control at a rate of 1 mm/sec. Cyclic elongation, peak-to-peak displacement, ultimate tensile load, and stiffness were measured with use of an optical motion analysis system and load-cell output. The type of failure (suture breakage or pull-out) was also recorded. A repeated-measures analysis of variance was performed on the results, with the alpha level of significance set at p < 0.05. RESULTS: There was no difference in cyclic elongation or peak-to-peak displacement among the four stitches. Ultimate tensile load was significantly higher (p < 0.05) for the massive cuff stitch (233 +/- 40 N) and the modified Mason-Allen stitch (246 +/- 40 N) than it was for either the simple stitch (72 +/- 18 N) or the horizontal stitch (77 +/- 15 N). There was no significant difference in the ultimate load between the massive cuff and modified Mason-Allen stitches. There was also no difference in stiffness among the four stitches. The simple and horizontal stitches failed by tissue pull-out, whereas the massive cuff and Mason-Allen stitches failed by a mixture of suture breakage and pull-out. CONCLUSIONS: The massive cuff stitch provides strength comparable with that of the modified Mason-Allen stitch commonly used in open rotator cuff repair. The ultimate tensile load before failure of the massive cuff stitch was significantly higher (p < 0.05) than that of the simple and horizontal stitches.     

Mechanical strength of arthroscopic rotator cuff repair techniques: an in vitro study

BACKGROUND: Retears after rotator cuff repairs occur relatively frequently and may compromise the functional result. The goal of this study was to analyze the mechanical properties following arthroscopic techniques for rotator cuff repair and to evaluate possible alternative techniques. METHODS: In the first part, five different bone anchors (the Revo screw; Mitek Rotator Cuff anchor, 5.0-mm Statak, PANALOK RC absorbable anchor, and 5.0-mm Bio-Statak) were tested in vitro under cyclic loading on five pairs of cadaveric shoulders. Then five types of arthroscopic tendon suturing instruments were tested on rotator cuff tendons. Finally, the arthroscopically performed mattress and modified Mason-Allen stitches, fixed with either the Revo screw or the Bio-Statak, were evaluated on ten pairs of human cadaveric shoulders. RESULTS: The holding strengths of the various anchors were similar, ranging from 130 to 180 N, and approximated the holding strength of knotted number-2 suture materials. The fixation of the tested anchors yielded comparable values of stiffness except for one anchor, which showed significantly greater subsidence under cyclic load (p = 0.003). All tested, commercially available arthroscopic suturing devices were unsuitable for performing a modified Mason-Allen stitch on normal supraspinatus tendons. Modification of a commercially available suture punch with a longer needle allowed us to consistently perform a modified Mason-Allen stitch. The modified Mason-Allen stitch, which has shown favorable mechanical properties in open repairs of the rotator cuff, was not found to be stronger than the mattress stitch when performed arthroscopically and used with bone anchors. When the modified Mason-Allen stitch was fixed to one anchor, it was even weaker than a mattress stitch repaired with another anchor (168 versus 228 N). Unequal loading of the two suture branches due to the more rigid modified Mason-Allen stitch may be the reason for this difference. CONCLUSIONS: Arthroscopic techniques for rotator cuff repair with use of the mattress stitch and bone anchors allow for a relatively solid fixation. The holding strength is not improved with use of the modified Mason-Allen stitch. Although a direct comparison with previous in vitro studies is not possible, the holding strength of open fixation techniques seems to be stronger. If rotator cuffs are subjected to high postoperative loading, open repair might be preferred to reduce the risk of a retear, until stronger arthroscopic fixation techniques are developed.     

关节镜下肩袖损伤缝合技术研究进展

关节镜下肩袖修补术已非常普遍.许多单排锚钉、双排锚钉和经骨隧道修复技术应用于临床,但肩袖修复的最佳方法仍不清楚.生物力学研究证明相比于单排,双排锚钉修复的力度更强,而单排锚钉中的巨大肩袖缝合技术和改良Mason-Allen缝合技术力学性能最佳.临床研究显示双排锚钉修复能改善肩袖愈合率,但各种缝合技术的预后功能评分无明显...     

A biomechanical comparison of single and double-row fixation in arthroscopic rotator cuff repair

BACKGROUND: The optimal method for arthroscopic rotator cuff repair is not yet known. The hypothesis of the present study was that a double-row repair would demonstrate superior static and cyclic mechanical behavior when compared with a single-row repair. The specific aims were to measure gap formation at the bone-tendon interface under static creep loading and the ultimate strength and mode of failure of both methods of repair under cyclic loading. METHODS: A standardized tear of the supraspinatus tendon was created in sixteen fresh cadaveric shoulders. Arthroscopic rotator cuff repairs were performed with use of either a double-row technique (eight specimens) or a single-row technique (eight specimens) with nonabsorbable sutures that were double-loaded on a titanium suture anchor. The repairs were loaded statically for one hour, and the gap formation was measured. Cyclic loading to failure was then performed. RESULTS: Gap formation during static loading was significantly greater in the single-row group than in the double-row group (mean and standard deviation, 5.0 +/- 1.2 mm compared with 3.8 +/- 1.4 mm; p < 0.05). Under cyclic loading, the double-row repairs failed at a mean of 320 +/- 96.9 N whereas the single-row repairs failed at a mean of 224 +/- 147.9 N (p = 0.058). Three single-row repairs and three double-row repairs failed as a result of suture cut-through. Four single-row repairs and one double-row repair failed as a result of anchor or suture failure. The remaining five repairs did not fail, and a midsubstance tear of the tendon occurred. CONCLUSIONS: Although more technically demanding, the double-row technique demonstrates superior resistance to gap formation under static loading as compared with the single-row technique. CLINICAL RELEVANCE: A double-row reconstruction of the supraspinatus tendon insertion may provide a more reliable construct than a single-row repair and could be used as an alternative to open reconstruction for the treatment of isolated tears.     

Comparative and experimental study on different tendinous grasping techniques in rotator cuff repair: a new reinforced stitch

Arthroscopic repair of wide rotator cuff ruptures is burdened by a percentage of recurrences that is greater than the repair carried out when an open technique is used. One of the main reasons for this difference can be searched for in the minor hold of stitching on the tendinous aspect obtained with arthroscopic repair. In fact, when an open technique is used, good hold can be guaranteed by using reinforced stitches such as the modified Mason-Allen. Thus, arthroscopic repair technique on the tendinous aspect, particularly in wide and massive injuries, must be improved. It was the purpose of this study to compare a new reinforced stitch that can easily be obtained in arthroscopy (simple stitch that orthogonally crosses a horizontal stitch previously knotted on the tendon: SS-HL), with traditional stitches (simple stitch, mattress-stitch and modified Mason-Allen stitch). Tests were carried out on sheep infraspinatus tendons in order to evaluate the resistance of pull-out. The SS-HL stitch showed resistance to loading that was similar to that when the modified Mason-Allen was used, but it was greater than that shown by the simple stitch (+48%) and the mattress stitch (+35%).     

Experimental rotator cuff repair. A preliminary study.

BACKGROUND: The repair of chronic, massive rotator cuff tears is associated with a high rate of failure. Prospective studies comparing different repair techniques are difficult to design and carry out because of the many factors that influence structural and clinical outcomes. The objective of this study was to develop a suitable animal model for evaluation of the efficacy of different repair techniques for massive rotator cuff tears and to use this model to compare a new repair technique, tested in vitro, with the conventional technique. METHODS: We compared two techniques of rotator cuff repair in vivo using the left shoulders of forty-seven sheep. With the conventional technique, simple stitches were used and both suture ends were passed transosseously and tied over the greater tuberosity of the humerus. With the other technique, the modified Mason-Allen stitch was used and both suture ends were passed transosseously and tied over a cortical-bone-augmentation device. This device consisted of a poly(L/D-lactide) plate that was fifteen millimeters long, ten millimeters wide, and two millimeters thick. Number-3 braided polyester suture material was used in all of the experiments. RESULTS: In pilot studies (without prevention of full weight-bearing), most repairs failed regardless of the technique that was used. The simple stitch always failed by the suture pulling through the tendon or the bone; the suture material did not break or tear. The modified Mason-Allen stitch failed in only two of seventeen shoulders. In ten shoulders, the suture material failed even though the stitches were intact. Thus, we concluded that the modified Mason-Allen stitch is a more secure method of achieving suture purchase in the tendon. In eight of sixteen shoulders, the nonaugmented double transosseous bone-fixation technique failed by the suture pulling through the bone. The cortical-bone-augmentation technique never failed. In definite studies, prevention of full weight-bearing was achieved by fixation of a ten-centimeter-diameter ball under the hoof of the sheep. This led to healing in eight of ten shoulders repaired with the modified Mason-Allen stitch and cortical-bone augmentation. On histological analysis, both the simple-stitch and the modified Mason-Allen technique caused similar degrees of transient localized tissue damage. Mechanical pullout tests of repairs with the new technique showed a failure strength that was approximately 30 percent of that of an intact infraspinatus tendon at six weeks, 52 percent of that of an intact tendon at three months, and 81 percent of that of an intact tendon at six months. CONCLUSIONS: The repair technique with a modified Mason-Allen stitch with number-3 braided polyester suture material and cortical-bone augmentation was superior to the conventional repair technique. Use of the modified Mason-Allen stitch and the cortical-bone-augmentation device transferred the weakest point of the repair to the suture material rather than to the bone or the tendon. Failure to protect the rotator cuff post-operatively was associated with an exceedingly high rate of failure, even if optimum repair technique was used. CLINICAL RELEVANCE: Different techniques for rotator cuff repair substantially influence the rate of failure. A modified Mason-Allen stitch does not cause tendon necrosis, and use of this stitch with cortical-bone augmentation yields a repair that is biologically well tolerated and stronger in vivo than a repair with the conventional technique. Unprotected repairs, however, have an exceedingly high rate of failure even if optimum repair technique is used. Postoperative protection from tension overload, such as with an abduction splint, may be necessary for successful healing of massive rotator cuff tears.     

Biomechanischer Vergleich aktueller Refixationsarten im Rahmen der Rekonstruktion von Rotatorenmanschettenläsionen in einem in-vivo-Tiermodell

A significant controversy exists regarding the optimal fixation technique in rotator cuff surgery. The aim of this study was to compare the time-dependent bio-mechanical properties of the traditional open transosseous suture technique and modified Mason-Allen stitches (SMMA group) versus the double-loaded suture anchor technique and so-called arthroscopic Mason-Allen stitches (AAMA group) in rotator cuff repair. A total of 18 mature sheep were randomized to the two repair groups. After 6, 12, or 26 weeks, evaluation of the reinsertion site of the infraspinatus tendon was performed. In a biomechanical evaluation all specimens were loaded to failure at a constant displacement rate using a standard universal testing machine. The load-to-failure and stiffness of the healed bone-tendon interface were calculated. Magnetic resonance imaging analysis showed cuff integrity in all cases and no evidence of foreign body reaction to the anchors. Load-to-failure and stiffness data did not indicate any significant difference between the two treatment groups, neither at 6 weeks nor at 12 or 26 weeks. However, at time zero the AAMA group had a higher load-to-failure in comparison to the SMMA group (P<0.010), but there was no difference for the stiffness (P<0.121). This in vivo study showed that the AAMA technique provides superior stability and after healing would gain strength comparable to the SMMA technique.     

Biomechanical comparison of single-row arthroscopic rotator cuff repair technique versus transosseous repair technique

This study determined the effect of tear size on gap formation of single-row simple-suture arthroscopic rotator cuff repair (ARCR) vs transosseous Mason-Allen suture open RCR (ORCR) in 13 pairs of human cadaveric shoulders. A massive tear was created in 6 pairs and a large tear in 7. Repairs were cyclically tested in low-load and high-load conditions, with no significant difference in gap formation. Under low-load, gapping was greater in massive tears. Under high-load, there was a trend toward increased gap with ARCR for large tears. All repairs of massive tears failed in high-load. Gapping was greater posteriorly in massive tears for both techniques. Gap formation of a modeled RCR depends upon the tear size. ARCR of larger tears may have higher failure rates than ORCR, and the posterior aspect appears to be the site of maximum gapping. Specific attention should be directed toward maximizing initial fixation of larger rotator cuff tears, especially at the posterior aspect.     

Arthroscopic Placement of a Modified Mason-Allen Stitch

Recent studies have shown all-arthroscopic rotator cuff repairs to have comparable clinical results to mini-open or open repairs. Previous drawbacks to arthroscopic repair have included not being able to place a modified Mason-Allen stitch with a suture anchor technique. We present a technique using the Arthrex Scorpion device (Arthrex, Naples, FL) to place a modified Mason-Allen stitch arthroscopically via a double-loaded FiberWire metal suture anchor (Arthrex). The Scorpion suture passer places a stitch from inferior to superior through the torn rotator cuff. The suture is grabbed and reloaded into the Scorpion device. The device is then turned upside down, and a horizontal stitch is placed from superior to inferior. The stitch is retrieved again and reloaded a third time. The last pass is placed so that the final stitch passes anterior to the inferior suture but beyond the previously placed horizontal mattress stitch. This effectively reproduces the described biomechanically superior modified Mason-Allen stitch.     

The outcome and structural integrity of arthroscopic rotator cuff repair with use of the double-row suture anchor technique

BACKGROUND: The reported rate of failure after arthroscopic rotator cuff repair has varied widely. The influence of the repair technique on the failure rates and functional outcomes after open or arthroscopic rotator cuff repair remains controversial. The purpose of the present study was to evaluate the functional and anatomic results of arthroscopic rotator cuff repairs performed with the double-row suture anchor technique on the basis of computed tomography or magnetic resonance imaging arthrography in order to determine the postoperative integrity of the repairs. METHODS: A prospective series of 105 consecutive shoulders undergoing arthroscopic double-row rotator cuff repair of the supraspinatus or a combination of the supraspinatus and infraspinatus were evaluated at a minimum of two years after surgery. The evaluation included a routine history and physical examination as well as determination of the preoperative and postoperative strength, pain, range of motion, and Constant scores. All shoulders had a preoperative and postoperative computed tomography arthrogram (103 shoulders) or magnetic resonance imaging arthrogram (two shoulders). RESULTS: There were thirty-six small rotator cuff tears, forty-seven large isolated supraspinatus or combined supraspinatus and infraspinatus tendon tears, and twenty-two massive rotator cuff tears. The mean Constant score (and standard deviation) was 43.2+/-15.1 points (range, 8 to 83 points) preoperatively and 80.1+/-11.1 points (range, 46 to 100 points) postoperatively. Twelve of the 105 repairs failed. Intact rotator cuff repairs were associated with significantly increased strength and active range of motion. CONCLUSIONS: Arthroscopic repair of a rotator cuff tear with use of the double-row suture anchor technique results in a much lower rate of failure than has previously been reported in association with either open or arthroscopic repair methods. Patients with an intact rotator cuff repair have better pain relief than those with a failed repair. After repair, large and massive rotator cuff tears result in more postoperative weakness than small tears do.     

Part II: Biomechanical assessment for a footprint-restoring transosseous-equivalent rotator cuff repair technique compared with a double-row repair technique

We hypothesized that a transosseous-equivalent repair would demonstrate improved tensile strength and gap formation between the tendon and tuberosity when compared with a double-row technique. In 6 fresh-frozen human shoulders, a transosseous-equivalent rotator cuff repair was performed: a suture limb from each of two medial anchors was bridged over the tendon and fixed laterally with an interference screw. In 6 contralateral matched-pair specimens, a double-row repair was performed. For all repairs, a materials testing machine was used to load each repair cyclically from 10 N to 180 N for 30 cycles; each repair underwent tensile testing to measure failure loads at a deformation rate of 1 mm/sec. Gap formation between the tendon edge and insertion was measured with a video digitizing system. The mean ultimate load to failure was significantly greater for the transosseous-equivalent technique (443.0 +/- 87.8 N) compared with the double-row technique (299.2 +/- 52.5 N) (P = .043). Gap formation during cyclic loading was not significantly different between the transosseous-equivalent and double-row techniques, with mean values of 3.74 +/- 1.51 mm and 3.79 +/- 0.68 mm, respectively (P = .95). Stiffness for all cycles was not statistically different between the two constructs (P > .40). The transosseous-equivalent rotator cuff repair technique improves ultimate failure loads when compared with a double-row technique. Gap formation is similar for both techniques. A transosseous-equivalent repair helps restore footprint dimensions and provides a stronger repair than the double-row technique, which may help optimize healing biology.     

An arthroscopic stitch for massive rotator cuff tears: the mac stitch

Arthroscopic repair of rotator cuff tears has become popular with the advancement in technology and arthroscopic technique. As we attempt to arthroscopically repair larger rotator cuff tears, we are relying more on tissue fixation. The tendon–suture interface has been recognized as the weak link in rotator cuff repair. In this article, we propose the use of the Mac stitch—a simple modification of suture placement, a combination of a horizontal and vertical loop at the site of repair—to increase the strength of tissue fixation. The Mac stitch is a simple arthroscopic stitch that can be used for small and massive rotator cuff repairs.     

Relative Fixation Strength of Rabbit Subscapularis Repair Is Comparable to Human Supraspinatus Repair at Time 0

Background

Recent evidence suggests that the rabbit subscapularis tendon may be anatomically, biomechanically, and histologically suitable to study rotator cuff pathology and repair. However, biomechanical comparisons of rotator cuff repairs in this model have not been evaluated and compared to those in human cadaveric specimens.

Questions/purposes

We quantified the biomechanical properties of the repaired rabbit subscapularis tendon after (1) single-row, (2) double-row, and (3) transosseous-equivalent rotator cuff repair techniques and compared the ratios of repairs to previously published data for human repairs.

Methods

Tensile testing was performed on 21 New Zealand White rabbit subscapularis tendon-humerus complexes for single-row repair, double-row repair, and transosseous-equivalent repair (n = 7 for each group). Video digitizing software was used to quantify deformation. Load elongation data were then used to quantify structural properties. We compared the ratios of rotator cuff repairs for the rabbit data to data from human supraspinatus repair studies previously performed in our laboratory. For our primary end points (linear stiffness, yield load, ultimate load, and energy absorbed to failure), with the numbers available, our statistical power to detect a clinically important difference (defined as 15%) was 85%.

Results

The ratios of single-row/double-row repair were 0.72, 0.73, 0.71, and 0.66 for human supraspinatus and 0.77, 0.74, 0.79, and 0.89 for rabbit subscapularis repair for linear stiffness, yield load, ultimate load, and energy absorbed to failure, respectively. The ratios of double-row/transosseous-equivalent repair were 1.0, 0.86, 0.70, and 0.41 for human supraspinatus and 1.22, 0.85, 0.76, and 0.60 for rabbit subscapularis for linear stiffness, yield load, ultimate load, and energy absorbed to failure, respectively. There were no differences comparing rabbit to human repair ratios for any parameter (p > 0.09 for all comparisons).

Conclusions

Subscapularis repairs in the rabbit at Time 0 result in comparable ratios to human supraspinatus repairs.

Clinical Relevance

The biomechanical similarities between the different types of rotator cuff repair in the rabbit subscapularis and human supraspinatus at Time 0 provide more evidence that the rabbit subscapularis may be an appropriate model to study rotator cuff repairs.     

A New Approach to Improving the Tissue Grip of the Medial-Row Repair in the Suture-Bridge Technique: The “Modified Lasso-Loop Stitch”

The double-row rotator cuff repair has proved to be biomechanically superior to the single-row technique. However, this has not been shown clinically. At the moment, all the methods proposed for medial-row suturing in the suture-bridge technique recommend a mattress suture or a simple stitch. The lasso-loop stitch has been proposed as a technique to improve tissue grip and has been used in open rotator cuff repairs, in biceps tenodesis, and in the Bankart procedure. We propose a method in which a modified version of this stitch can be used to repair the medial row of a double-row repair. In the “modified lasso-loop stitch,” a circumferential stitch is constructed over the posteromedial and anteromedial anchor. This stitch exerts an appropriate amount of radial compression on the encased tendon as the tails of the posteromedial and anteromedial suture are fixed to the anterolateral anchor. Through this technique, the reduction force is augmented and a compression force is created, thus allowing restoration of the rotator cuff footprint. This technique provides a strong cuff-suture interface while appropriate tensioning of the modified lasso-loop stitch allows minimal strangulation of the tendon. This technique has been shown to work with and without a knot.     

关节镜下双排固定治疗肩袖损伤

目的 观察关节镜下单排、双排固定治疗肩袖损伤的近期效果. 方法 对8例肩袖损伤采用单排固定,7例肩袖损伤进行双排固定,观察术后功能恢复情况,进行UCLA评分. 结果 双排固定术后恢复时间短,功能恢复快,UCLA评分明显优于单排固定.单排固定组2例锚钉拔出,行再次手术固定;2例术后锻炼时出现疼痛和术前症状,再次手术时发现缝合线断裂,予再次固定. 结论 肩袖损伤的关节镜下双排固定效果明显优于单排固定,双排固定不仅增加了固定强度,同时使肩袖肌腱断端与肱骨大结节的接触面积大大增加,更有利于腱骨愈合.     

Arthroscopic rotator cuff repair with double-row fixation

BACKGROUND: The treatment of rotator cuff tears has evolved from open surgical repairs to complete arthroscopic repairs over the past two decades. In this study, we reviewed the results of arthroscopic rotator cuff repairs with the so-called double-row, or footprint, reconstruction technique. METHODS: Between 1998 and 2002, 264 patients underwent an arthroscopic rotator cuff repair with double-row fixation. The average age at the time of the operation was fifty-nine years. Two hundred and thirty-eight patients (242 shoulders) were available for follow-up; 210 were evaluated with a full clinical examination and thirty-two, with a questionnaire only. Preoperative and postoperative examinations consisted of determination of a Constant score and a visual analogue score for pain as well as a full physical examination of the shoulder. Ultrasonography was done at a minimum of twelve months postoperatively to assess the integrity of the cuff. RESULTS: The average score for pain improved from 7.4 points (range, 3 to 10 points) preoperatively to 0.7 point (range, 0 to 3 points) postoperatively. The subjective outcome was excellent or good in 220 (90.9%) of the 242 shoulders. The average increase in the Constant score after the operation was 25.4 points (range, 0 to 57 points). Ultrasonography demonstrated an intact rotator cuff in 83% (174) of the shoulders overall, 47% (fifteen) of the thirty-two with a repair of a massive tear, 78% (thirty-two) of the forty-one with a repair of a large tear, 93% (113) of the 121 with a repair of a medium tear, and 88% (fourteen) of the sixteen with a repair of a small tear. Strength and active elevation increased significantly more in the group with an intact repair at the time of follow-up than in the group with a failed repair; however, there was no difference in the pain scores. CONCLUSIONS: Arthroscopic rotator cuff repair with double-row fixation can achieve a high percentage of excellent subjective and objective results. Integrity of the repair can be expected in the majority of shoulders treated for a large, medium, or small tear, and the strength and range of motion provided by an intact repair are significantly better than those following a failed repair. LEVEL OF EVIDENCE: Therapeutic Level IV.     

Tensile strength of a new suture for fixation of tendon grafts when using a weave technique

PURPOSE: To evaluate a new corner stitch construct for tendon graft or tendon transfer fixation and compare the tensile strength with a conventional central cross-suture design in human cadaver tendons. METHODS: Flexor digitorum profundus tendons of the index, middle, and ring fingers (48 total) were used as recipients and palmaris longus, extensor indicis proprius, and extensor digitorum communis tendons of the index finger (48 total) were used as grafts from 16 fresh-frozen human cadaver hands. We compared the cross-stitch technique with a new corner stitch technique in tendon repairs made with 1, 2, or 3 weaves (8 per group). Tendons were sutured at each weave with either 2 full-thickness cross-stitches or 4 partial-thickness corner stitches of 4-0 nylon. Mattress sutures also were placed through the free tendon end for each repair type. The tensile strength of the tendon-graft composite was measured with a materials testing machine. RESULTS: The tensile strength of the repairs increased significantly with the number of weaves. When 2 or 3 weaves were used with the corner stitch or when 3 weaves were used with the cross-stitch, the repairs were significantly stronger. Although no significant difference in strength to failure was noted when comparing cross and corner stitches with equivalent numbers of weaves, qualitatively there was a difference in mode of failure with the 3-weave corner stitches failing primarily by intrasubstance tendon failure and the 3-weave cross-stitch repairs failing by tendon pullout. CONCLUSIONS: The corner stitch is as strong as conventional cross-stitch repairs and its superficial placement may be more favorable to tendon blood supply. This repair may be advantageous for clinical applications.     

Editorial Commentary: Biology and Biomechanics Must Be Carefully Balanced for a Durable Rotator Cuff Repair

Arthroscopic rotator cuff repair strategies have evolved over 3 decades, but suture anchor design, anchor configuration, and stitches have been largely driven by repair biomechanics. In recent years there has been a shift toward repair strategies that enhance the biology of tendon repair. Double-row and transosseous equivalent suture anchor repair constructs demonstrate excellent time zero mechanical properties, but the resulting increased repair tension and tendon compression may compromise tendon healing. Modern single-row repairs employing medialized triple-loaded suture anchors, simple stitches, and lateral marrow venting avoid some of the problems associated with double-row repairs and demonstrate excellent short-term healing and clinical results. The most robust repair fails if the tendon does not heal. Biology and biomechanics must be carefully balanced.     

Repair integrity and functional outcome after arthroscopic double-row rotator cuff repair. A prospective outcome study

BACKGROUND: The retear rate following rotator cuff repair is variable. Recent biomechanical studies have demonstrated that double-row tendon-to-bone fixation excels in initial fixation strength and footprint coverage compared with the single-row or transosseous fixation methods. This study was designed to report the repair integrity and clinical outcome following arthroscopic double-row rotator cuff repair. METHODS: A consecutive series of 106 patients with full-thickness rotator cuff tears underwent arthroscopic double-row rotator cuff repair with use of suture anchors and were followed prospectively. Twenty patients lacked complete follow-up data or were lost to follow-up. The eighty-six study subjects included fifty-two men and thirty-four women, with an average age of 60.5 years. There were twenty-six small, thirty medium, twenty-two large, and eight massive tears. Clinical outcomes were evaluated at an average of thirty-one months. Repair integrity was estimated with use of magnetic resonance imaging, which was performed, on the average, fourteen months postoperatively, and was classified into five categories, with type I indicating sufficient thickness with homogeneously low intensity; type II, sufficient thickness with partial high intensity; type III, insufficient thickness without discontinuity; type IV, the presence of a minor discontinuity; and type V, the presence of a major discontinuity. RESULTS: The average clinical outcome scores all improved significantly at the time of the final follow-up (p < 0.01). At a mean of fourteen months postoperatively, magnetic resonance imaging revealed that thirty-seven shoulders had a type-I repair; twenty-one, a type-II repair; thirteen, a type-III repair; eight, a type-IV repair; and seven, a type-V repair. The overall rate of retears (types IV and V) was 17%. The retear rate was 5% for small-to-medium tears, while it was 40% for large and massive tears. The shoulders with a type-V repair demonstrated significantly inferior functional outcome in terms of overall scores and strength compared with the other types of repairs (p < 0.01). CONCLUSIONS: Arthroscopic double-row repair can result in improved repair integrity compared with open or miniopen repair methods. However, the retear rate for shoulders with large and massive tears remains higher than that for smaller tears, and shoulders with large repair defects (type V) demonstrate significantly inferior functional outcomes.     

Single row rotator cuff repair with modified technique

Rotator cuff tear is a common medical condition. We introduce various suture methods that can be used for arthroscopic rotator cuff repair, review the single row rotator cuff repair method with modified technique, and introduce the Ulsan-University (UU) stich. We compare the UU stitch with the modified Mason-Allen (MA) suture method. The UU stitch configuration is a simple alternative to the modified MA suture configuration for rotator cuff repair.