Mode of failure for rotator cuff repair with suture anchors identified at revision surgery

Rotator cuff tears are a common cause of shoulder pain and dysfunction. After surgical repair, there is a significant re-tear rate (25%-90%). The aim of this study was to determine the primary mode of mechanical failure for rotator cuffs repaired with suture anchors at the time of revision rotator cuff repair. We prospectively followed 342 consecutive torn rotator cuffs, repaired by a single surgeon using suture anchors and a mattress-suturing configuration. Of those shoulders, 21 (6%) subsequently underwent a revision rotator cuff repair by the original surgeon, and 1 underwent a second revision repair. Intraoperative findings, including the mode of failure, were systematically recorded at revision surgery and compared with the findings at the primary repair. In addition, 81 primary rotator cuff repairs had a radiographic and fluoroscopic evaluation at a mean of 37 weeks after repair to assess for any loosening or migration of the anchors. At revision rotator cuff repair, the predominant mode of failure was tendon pulling through sutures (19/22 shoulders) (P <.001). Two recurrent tears occurred in a new location adjacent to the previous repair, and one anchor was found loose in the supraspinatus tendon. The mean size of the rotator cuff tear was larger at the revision surgery (P =.043), the tendon quality ranked poorer (P =.013), and the tendon mobility decreased (P =.002), as compared with the index procedure. The radiographs and fluoroscopic examination showed that all 335 anchors in 81 patients were in bone. Rotator cuff repairs with suture anchors that underwent revision surgery failed mechanically by three mechanisms, the most common of which was tendon pulling through sutures. This suggests that the weak link in rotator cuff repairs with suture anchors and horizontal mattress sutures, as determined at revision surgery, is the tendon-suture interface.     

The effects of chronic unloading and gap formation on tendon‐to‐bone healing in a rat model of massive rotator cuff tears

The objective of this study was to understand the effect of pre‐repair rotator cuff chronicity on post‐repair healing outcomes using a chronic and acute multi‐tendon rat rotator cuff injury model. Full‐thickness dual tendon injuries (supra‐ and infraspinatus) were created unilaterally in adult male Sprague Dawley rats, and left chronically detached for 8 or 16 weeks. After chronic detachment, tears were repaired and acute dual tendon injuries were created and immediately repaired on contralateral shoulders. Tissue level outcomes for bone, tendon, and muscle were assessed 4 or 8 weeks after repair using histology, microcomputed tomography, biomechanical testing, and biochemical assays. Substantial gap formation was seen in 35% of acute repairs and 44% of chronic repairs. Gap formation negatively correlated with mechanical and structural outcomes for both healing time points regardless of injury duration. Bone and histomorphometry, as well as biomechanics, were similar between acute and chronic injury and repair regardless of chronicity and duration of healing. This study was the first to implement a multi‐tendon rotator cuff injury with surgical repair following both chronic and acute injuries. Massive tear in a rodent model resulted in gap formation regardless of injury duration which had detrimental effects on repair outcomes. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:439–447, 2014.     

Tissue‐engineered tendon constructs for rotator cuff repair in sheep

Current rotator cuff repair commonly involves the use of single or double row suture techniques, and despite successful outcomes, failure rates continue to range from 20 to 95%. Failure to regenerate native biomechanical properties at the enthesis is thought to contribute to failure rates. Thus, the need for technologies that improve structural healing of the enthesis after rotator cuff repair is imperative. To address this issue, our lab has previously demonstrated enthesis regeneration using a tissue‐engineered graft approach in a sheep anterior cruciate ligament (ACL) repair model. We hypothesized that our tissue‐engineered graft designed for ACL repair also will be effective in rotator cuff repair. The goal of this study was to test the efficacy of our Engineered Tissue Graft for Rotator Cuff (ETG‐RC) in a rotator cuff tear model in sheep and compare this novel graft technology to the commonly used double row suture repair technique. Following a 6‐month recovery, the grafted and contralateral shoulders were removed, imaged using X‐ray, and tested biomechanically. Additionally, the infraspinatus muscle, myotendinous junction, enthesis, and humeral head were preserved for histological analysis of muscle, tendon, and enthesis structure. Our results showed that our ETC‐RCs reached 31% of the native tendon tangent modulus, which was a modest, non‐significant, 11% increase over that of the suture‐only repairs. However, the histological analysis showed the regeneration of a native‐like enthesis in the ETG‐RC‐repaired animals. This advanced structural healing may improve over longer times and may diminish recurrence rates of rotator cuff tears and lead to better clinical outcomes. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:289–299, 2018.     

Arthroscopic Intratendinous Repair of the Delaminated Partial-Thickness Rotator Cuff Tear in Overhead Athletes

A distinct type of partial-thickness rotator cuff tear has been observed in overhead athletes, characterized by partial failure of the undersurface of the posterior supraspinatus and anterior infraspinatus tendons with intratendinous delamination. We present a technique of percutaneous intratendinous repair using nonabsorbable mattress sutures designed for the management of articular-side delaminated partial-thickness tears. After tear evaluation and preparation, the torn rotator cuff undersurface is held in a reduced position with a grasper through an anterolateral rotator interval portal while viewing intra-articularly. Two spinal needles are then placed percutaneously through the full thickness of the torn and intact rotator cuff. A polydioxanone suture is passed through each needle, retrieved out the anterior portal, and used to shuttle a single nonabsorbable No. 2 suture through the tissue, creating a mattress suture. Multiple mattress sutures can be placed as dictated by tear size and morphology, with suture retrieval and knot securing then proceeding in the subacromial space. We have adopted this approach with the goals of anatomically re-establishing the rotator cuff insertion and sealing the area of intratendinous delamination while preventing significant alteration to the anatomy of the rotator cuff insertion, which could lead to motion deficits, internal impingement, and potential tear recurrence.     

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.     

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.     

A biodegradable button to augment suture attachment in rotator cuff repair

Recent experimental studies suggest that the use of suture anchors for rotator cuff tear (RCT) repair transfers the "weak link" to the suture-tendon interface where failure occurs as the sutures cut through the tendon. The purpose of this study was to evaluate the effect of using a suture augmentation button on the fixation strength of rotator cuff tendon repair. A 1.5 cm by 2 cm defect was created in the supraspinatus tendon of seven cadaveric shoulder pairs and two suture anchors inserted in each humerus for suture attachment. For one of each pair, the defect was repaired with sutures placed in a horizontal mattress configuration. The other side was repaired with the sutures being passed through low profile, bioabsorbable buttons placed on the bursal tendon surface prior to knot tying. The supraspinatus tendon was cyclically loaded at a physiologic rate and load (33 mm/sec and 180 N, respectively). The number of loading cycles was recorded when the specimens developed 0.75 cm and 1.5 cm gaps at the repair site. The specimens were then tested to failure. Specimens in the unaugmented group developed 0.75 cm and 1.5 cm gaps at an average of 135 cycles and 362 cycles, respectively. The button augmented group developed these gaps at average of 420 cycles and 708 cycles, respectively. These differences were statistically significant (p < 0.05). The gaps progressively increased in all specimens, which eventually failed by suture cutting through tendon in all specimens. This study demonstrates that in vitro, suture augmentation with a low profile, bioabsorbable button provides significantly enhanced fixation when using suture anchors to repair torn rotator cuff tendon. This device may be a useful adjunct to current methods of rotator cuff repair.     

Mattress suture-bridge technique for bursal-side partial-thickness rotator cuff tears

The standard procedure used to repair partial-thickness tears involves initial progression of the lesion to a full-thickness tear prior to tendon repair. However, the option for a bursal-side partial-thickness rotator cuff tear includes the preservation of as much of the remaining intact fibers as possible. Instead of inserting suture anchors in the medial row, as in the conventional suture-bridge technique, two mattress sutures are inserted into the rotator cuff. Full-thickness access is achieved using a percutaneous spinal needle and medial mattress sutures to preserve the articular bone attachment of the remnant fibers and to compress the repaired tendon on the footprint. Our method can help preserve the remnant rotator cuff tendon without tissue damage and can restore the normal rotator cuff footprint.     

“Transosseous-Equivalent” Rotator Cuff Repair Technique

In order to optimize healing biology at a repaired rotator cuff footprint, we have developed a “transosseous-equivalent” rotator cuff repair that can be performed arthroscopically. What the arthroscopically repaired tendon experiences is “equivalent” to what is experienced with a traditional open suture-bridge technique. This repair maximizes the utility of a single-row repair technique by preserving the suture limbs of the medial single-row and bridging these sutures over the footprint insertion with distal-lateral interference screw suture fixation; the medial row uses a mattress suture configuration. The geometry of the construct compresses the tendon, optimizing tendon-to-tuberosity contact dimensions, while providing strength sufficient to withstand immediate postoperative rehabilitation.     

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.

Biomechanical comparison of suture anchor versus margin convergence plus suture anchor for rotator cuff repair

Objective: To evaluate results of margin convergence versus suture anchors in rotator cuff repair, and to determine which method is mechanically superior. Methods: Eighteen kangaroo shoulders were randomly divided into three groups (n = 6). A full thickness tendon defect 1.0 cm × 1.5 cm in size was created in the supraspinatus tendon at humeral insertion, simulating a massive rotator cuff tear. Three different techniques were employed for rotator cuff repair: (i) Mitek GII suture anchor alone (Group 1); (ii) margin convergence alone (Group 2); and (iii) margin convergence plus Mitek GII suture anchor (Group 3). Combined loads were applied to each specimen. After completion of cyclic loading, the construct was loaded to failure. ANOVA and LSD (Least Significant Difference) multiple comparisons of the means were applied to results. Results: Cyclic load testing showed progressive gap formation in each repaired specimen with increasing cycles. Group 1 reached 50% failure at an average of 34 cycles, Group 2 at 75 cycles and Group 3 at 73 cycles. There were significant difference between Groups 1 and 2, and Groups 1 and 3 (P ≤ 0.001). After 100 loading cycles, the average gap size was 6.8 mm, 6.1 mm and 4.7 mm in Groups 1, 2 and 3, respectively. There was a significant difference between Groups 1 and 3 (P ≤ 0.015). All specimens eventually reached failure. Conclusion: Rotator cuff repairs with margin convergence +/? suture anchor were far stronger than suture anchor alone, both in gap formation and ultimate failure load. However, progressive gap formation with cyclic loading seems inevitable after cuff repair, which may facilitate clinical understanding of the phenomena of re‐tear or residual defect.     

The low-profile Roman bridge technique for knotless double-row repair of the rotator cuff

With advances in arthroscopic surgery, many techniques have been developed to increase the tendon–bone contact area, reconstituting a more anatomic configuration of the rotator cuff footprint and providing a better environment for tendon healing. We present a low-profile arthroscopic rotator cuff repair technique which uses suture bridges to optimize rotator cuff tendon–footprint contact area and mean pressure. A 5.5 mm Bio-Corkscrew suture anchor (Arthrex, Naples, FL, USA), double-loaded with No. 2 FiberWire sutures (Arthrex, Naples, FL, USA), is placed in the anteromedial aspect of the footprint. Two suture limbs from a single suture are both passed through a single anterior point in the rotator cuff. One suture limb is retrieved from the cannula. The second suture limb is passed through a single posterior point in the rotator cuff producing two points of fixation in the tendon, with a tendon bridge between them. The same suture limb is retrieved through the lateral portal, and then inserted into the bone by means of a Pushlock (Arthrex, Naples, FL, USA), placed approximately 1.5–2 cm posterior to the first anchor. This second suture is passed again in the posterior aspect of the cuff. The limbs of the first suture are pulled to compress the tendon in the medial aspect of the footprint. The two free suture limbs are used to produce suture bridges over the tendon by means of a Pushlock (Arthrex, Naples, FL, USA), placed 1 cm distal to the lateral edge of the footprint relative to the medially placed suture anchors anterior to posterior. This technique allows us to perform a low-profile (single pulley–suture bridges) repair for knotless double-row repair of the rotator cuff.     

Biomechanical evaluation of a rotator cuff defect model augmented with a bioresorbable scaffold in goats

A bioresorbable patch used for augmentation of rotator cuff repair was evaluated to determine if it would increase strength of cuff repairs associated with tendon defects and also show histologic incorporation over time. Forty goats underwent rotator cuff repairs of the infraspinatus tendon bilaterally. Tendons were detached and a defect was created prior to repair. One side was repaired and augmented with a 4 cm2 polylactic acid patch in each animal. On the other side, the same size defect was repaired in the same manner but without the patch to serve as a control. Animals were sacrificed at 3, 6, 12, and 24 weeks. Ultimate load to failure and histology were reported. No significant difference in load to failure was found between groups. A cellular fibrous tissue occupied the patch at 6 weeks, which over time matured into a dense, homogeneous fibrous tissue with alignment of collagen between the scaffold bundles.     

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. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1254–1260, 2013     

切开修补治疗肩袖撕裂的中远期随访

目的 对切开行肩袖修补术的肩袖撕裂患者行中远期随访,分析术前、术中因素对手术疗效的影响.方法 回顾性研究1987年5月至2002年10月在北京医院骨科进行切开手术修补撕裂肩袖的43例患者(44肩).男20例(21肩),女23例(23肩);手术时平均年龄53岁(22～76岁).13肩为小型撕裂(＜1 cm),18肩为中型撕裂(1～3 cm),10肩为大型撕裂(3～5 cm),3肩为巨大型撕裂(＞5 cm).撕裂累及冈上肌31肩,累及冈上肌和冈下肌9肩,累及冈上肌和肩胛下肌3肩,累及冈上肌、冈下肌和肩胛下肌1肩.以Mclaughlin术(肌腱-骨)修补25肩,以肌腱-骨联合肌腱-肌腱缝合法修补11肩,以肌腱-肌腱缝合法修补7肩,三角肌深部肌腱转位术(高岸式)修补1肩.术后平均随访88.2个月(52～250个月),以美国加州大学洛杉矶分校(University of California at Los Angeles,UCLA)功能评分评价患者手术前后的肩关节功能,以视觉模拟评分系统(visual analogue scale,VAS)分析患者对手术效果的主观评价.对患者的年龄、性别、优势手、外伤史、手术前病程和肩袖撕裂大小等因素对预后的影响行统计学分析.结果 44肩UCLA评分术前平均为(11.5±2.8)分,末次随访时平均为(29.7±5.3)分.36肩得分＞28分,达到优或良;6肩为可;2肩得分＜20分,评定为差.患者对39肩的手术疗效满意,主观满意率89%.患者主观满意度与UCLA评分呈显著正相关(r=0.72,P＜0.01).肩袖撕裂的大小(r=-0.404,P=0.007)、术前病程(r=-0.332,P=0.028)与术后结果呈负相关,即肩袖撕裂范围越大、术前病程越长,手术疗效就越差.而手术患者的年龄、性别、优势手、外伤史与手术的预后无关.结论 切开修补治疗肩袖全层撕裂能获得满意的中远期疗效,肩袖的撕裂大小、术前病程与术后结果呈负相关.     

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.     

A Modified Suture-Bridge Technique for a Marginal Dog-Ear Deformity Caused During Rotator Cuff Repair

Recently, the suture-bridge technique was found to maximize the utility of a single-row construct by using the suture limbs from the medial mattress sutures to bridge and compress the repaired tendon. However, the formation of marginal dog-ear deformities at a repaired rotator cuff is not uncommon with the suture-bridge technique. If a dog-ear deformity is observed at the margin after completion of the rotator cuff repair, the detached marginal cuff is pierced via a suture hook. One strand of the uncut suture in the lateral row is transported through the deformed cuff. A nonsliding knot is seated on top of the detached cuff and presses this area of soft tissue firmly onto the bone. If necessary, these steps are repeated for the other side of the detached rotator cuff. After completion of the rotator cuff repair, a “zigzag” pattern of compression of the cuff against the bone footprint without detachment of the rotator cuff is observed. After repair of the rotator cuff tear via the suture-bridge technique, the benefit of our simple technique for treating a marginal detached cuff is that the footprint contact area of the rotator cuff is restored completely, without the need for additional suture anchors.     

Arthroscopic repair of full-thickness tears of the supraspinatus: does the tendon really heal?

BACKGROUND: Good functional results have been reported for arthroscopic repair of rotator cuff tears, but the rate of tendon-to-bone healing is still unknown. Our hypothesis was that arthroscopic repair of full-thickness supraspinatus tears achieves a rate of complete tendon healing equivalent to those reported in the literature with open or mini-open techniques. METHODS: Sixty-five consecutive shoulders with a chronic full-thickness supraspinatus tear were repaired arthroscopically in sixty-five patients with use of a tension-band suture technique. Patients ranged in age from twenty-nine to seventy-nine years. The average duration of follow-up was twenty-nine months. Fifty-one patients (fifty-one shoulders) had a computed tomographic arthrogram, and fourteen had a magnetic resonance imaging scan, performed between six months and three years after surgery. All patients were assessed with regard to function and the strength of the shoulder elevation. RESULTS: The rotator cuff was completely healed and watertight in forty-six (71%) of the sixty-five patients and was partially healed in three. Although the supraspinatus tendon did not heal to the tuberosity in sixteen shoulders, the size of the persistent defect was smaller than the initial tear in fifteen. Sixty-two of the sixty-five patients were satisfied with the result. The Constant score improved from an average (and standard deviation) of 51.6 +/- 10.6 points preoperatively to 83.8 +/- 10.3 points at the time of the last follow-up evaluation (p < 0.001), and the average University of California at Los Angeles score improved from 11.5 +/- 1.1 to 32.3 +/- 1.3 (p < 0.001). The average strength of the shoulder elevation was significantly better (p = 0.001) when the tendon had healed (7.3 +/- 2.9 kg) than when it had not (4.7 +/- 1.9 kg). Factors that were negatively associated with tendon healing were increasing age and associated delamination of the subscapularis or infraspinatus tendon. Only ten (43%) of twenty-three patients over the age of sixty-five years had completely healed tendons (p < 0.001). CONCLUSIONS: Arthroscopic repair of an isolated supraspinatus detachment commonly leads to complete tendon healing. The absence of healing of the repaired rotator cuff is associated with inferior strength. Patients over the age of sixty-five years (p = 0.001) and patients with associated delamination of the subscapularis and/or the infraspinatus (p = 0.02) have significantly lower rates of healing.     

The effect of suture materials and techniques on the outcome of repair of the rotator cuff: a prospective, randomised study

In a prospective, randomised study on the repair of tears of the rotator cuff we compared the clinical results of two suture techniques for which different suture materials were used. We prospectively randomised 100 patients with tears of the rotator cuff into two groups. Group 1 had transosseous repair with No. 3 Ethibond using modified Mason-Allen sutures and group 2 had transosseous repair with 1.0 mm polydioxanone cord using modified Kessler sutures. After 24 to 30 months the patients were evaluated clinically using the Constant score and by ultrasonography. Of the 100 patients, 92 completed the study. No significant statistical difference was seen between the two groups: Constant score, 91% vs 92%; rate of further tear, 18% vs 22%; and revision, 4% vs 4%. In cases of further tear the outcome in group 2 did not differ from that for the intact repairs (91% vs 91%), but in group 1 it was significantly worse (94% vs 77%, p = 0.005). Overall, seven patients had complications which required revision surgery, in four for pain (two in each group) and in three for infection (two in group 1 and one in group 2).     

Restoration of anterior–posterior rotator cuff force balance improves shoulder function in a rat model of chronic massive tears

The rotator cuff musculature imparts dynamic stability to the glenohumeral joint. In particular, the balance between the subscapularis anteriorly and the infraspinatus posteriorly, often referred to as the rotator cuff “force couple,” is critical for concavity compression and concentric rotation of the humeral head. Restoration of this anterior–posterior force balance after chronic, massive rotator cuff tears may allow for deltoid compensation, but no in vivo studies have quantitatively demonstrated an improvement in shoulder function. Our goal was to determine if restoring this balance of forces improves shoulder function after two‐tendon rotator cuff tears in a rat model. Forty‐eight rats underwent detachment of the supraspinatus and infraspinatus. After four weeks, rats were randomly assigned to three groups: no repair, infraspinatus repair, and two‐tendon repair. Quantitative ambulatory measures including medial/lateral forces, braking, propulsion, and step width were significantly different between the infraspinatus and no repair group and similar between the infraspinatus and two‐tendon repair groups at almost all time points. These results suggest that repairing the infraspinatus back to its insertion site without repair of the supraspinatus can improve shoulder function to a level similar to repairing both the infraspinatus and supraspinatus tendons. Clinically, a partial repair of the posterior cuff after a two‐tendon tear may be sufficient to restore adequate function. An in vivo model system for two‐tendon repair of massive rotator cuff tears is presented. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1028–1033, 2011