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 an arthroscopic rotator cuff repair technique which uses suture bridges to optimize rotator cuff tendon-footprint contact area and mean pressure.
Two medial row 5.5-mm Bio-Corkscrew suture anchors (Arthrex, Naples, FL), which are double-loaded with No. 2 FiberWire sutures (Arthrex, Naples, FL), are placed in the medial aspect of the footprint. Two suture limbs from a single suture are both passed through a single point in the rotator cuff. This is performed for both anchors. The medial row sutures are tied using the double pulley technique. A suture limb is retrieved from each of the medial anchors through the lateral portal, and manually tied as a six-throw surgeon's knot over a metal rod. The two free suture limbs are pulled to transport the knot over the top of the tendon bridge. Then the two free suture limbs that were used to pull the knot down are tied. The end of the sutures are cut. The same double pulley technique is repeated for the other two suture limbs from the two medial anchors, but the two free suture limbs are used to produce suture bridges over the tendon, by means of a Pushlock (Arthrex, Naples, FL), placed 1 cm distal to the lateral edge of the footprint.
This technique maximizes the advantages of two techniques. On the one hand, the double pulley technique provides an extremely secure fixation in the medial aspect of the footprint. On the other hand, the suture bridges allow to improve pressurized contact area and mean footprint pressure. In this way, the bony footprint in not compromised by the distal-lateral fixation, and it is thus possible to share the load between fixation points. This maximizes the strength of the repair and provides a barrier preventing penetration of synovial fluid into the healing area of tendon and bone.
Rotator cuff tears are frequently associated with pathologies of the long head of the biceps tendon (LHBT). Tenotomy and tenodesis of the LHBT are commonly used to manage disorders of the LHBT.
We present an arthroscopic soft tissue LHBT tenodesis associated with a Roman Bridge (double pulley – suture bridges) repair
Two medial row 5.5-mm Bio-Corkscrew suture anchors (Arthrex, Naples, FL), double-loaded with No. 2 FiberWire sutures (Arthrex, Naples, FL), are placed in the medial aspect of the footprint. A shuttle is passed through an anterior point of the rotator cuff and through the LHBT by means of a Penetrator or a BirdBeak suture passer (Arthrex, Naples, FL). A tenotomy of the LHBT is performed. All the sutures from the anteromedial anchor are passed through a single anterior point in the rotator cuff using a shuttle technique. All the sutures from the posteromedial anchor are passed through a single posterior point in the rotator cuff. The sutures in the medial row are tied using the double pulley technique. A suture limb is retrieved from each of the medial anchors and manually tied as a six-throw surgeon's knot over a metal rod. The two free suture limbs are pulled to transport the knot over the top of the tendon bridge. The two free suture limbs are then used to produce suture bridges over the tendon, using a Pushlock (Arthrex, Naples, FL), placed 1 cm distal to the lateral edge of the footprint. The same double pulley – suture bridges technique is repeated for the other two suture limbs from the two medial anchors.
This technique allows to perform a double pulley – suture bridges repair for a rotator cuff tear, associated with a soft tissue tenodesis for the management of LHBT pathology. The tenodesis of the LHBT is performed just with the passage of a shuttle inside the LHBT, after passing it through the anterior portion of the rotator cuff, with successive detachment of the LHBT from the glenoid. It is a technically easy procedure which can be performed relatively quickly, and does not require additional fixation.
This experimental study aimed to compare the load-to-failure rate and stiffness of single- versus double-row suture techniques for repairing rotator cuff lesions using two different suture materials. Additionally, the mode of failure of each repair was evaluated.
In 32 sheep shoulders, a standardized tear of the infraspinatus tendon was created. Then, n = 8 specimen were randomized to four repair methods: (1) Double-row Anchor Ethibond® coupled with polyester sutures, USP No. 2; (2) Double-Row Anchor HiFi® with polyblend polyethylene sutures, USP No. 2; (3) Single-Row Anchor Ethibond® coupled with braided polyester sutures, USP No. 2; and (4) Single-Row Anchor HiFi® with braided polyblend polyethylene sutures, USP No. 2. Arthroscopic Mason–Allen stitches were placed (single-row) and combined with medial horizontal mattress stitches (double-row). All specimens were loaded to failure at a constant displacement rate on a material testing machine.
Group 4 showed lowest load-to-failure result with 155.7 ± 31.1 N compared to group 1 (293.4 ± 16.1 N) and group 2 (397.7 ± 7.4 N) (P < 0.001). Stiffness was highest in group 2 (162 ± 7.3 N/mm) and lowest in group 4 (84.4 ± 19.9 mm) (P < 0.001). In group 4, the main cause of failure was due to the suture cutting through the tendon (n = 6), a failure case observed in only n = 1 specimen in group 2 (P < 0.001).
A double-row technique combined with arthroscopic Mason-Allen/horizontal mattress stitches provides high initial failure strength and may minimize the risk of the polyethylene sutures cutting through the tendon in rotator cuff repair when a single load force is used.
Rotator cuff; Single-row; Double-row; Load-to-failure; Sheep shoulder
Despite advancements in arthroscopic rotator cuff repair techniques, achieving tendon-to-bone healing can be difficult in the setting of poor-quality tendon. Moreover, medial tendon tears or tears with lateral tendon loss may preclude standard techniques. Rip-stop suture configurations have been shown to improve load to failure compared with simple or mattress stitch patterns and may be particularly valuable in these settings. The purpose of this report is to describe a technical modification of a rip-stop rotator cuff repair that combines the advantages of a rip-stop suture (by providing resistance to tissue cutout) and a double row of load-sharing suture anchors (minimizing the load per anchor and therefore the load per suture within each anchor).
Although presumed, damage in the remaining (intact) rotator cuff tendons in the presence of an isolated supraspinatus tendon tear or multiple tendon tear has not been well studied. This study utilized an animal model of multiple rotator cuff tendon tears to investigate alterations in the remaining (intact) tendon mechanical properties at 4 and 8 weeks post-injury. Twenty-four animals served as uninjured controls, while seventy-two were divided among the tendon detachment groups (supraspinatus tendon detachment, supraspinatus+infraspinatus tendon detachment, supraspinatus+subscapularis tendon detachment). We found the remaining (intact) rotator cuff tendons have decreased mechanical properties in the presence of rotator cuff tears. Remaining (intact) subscapularis and infraspinatus tendon cross-sectional area increased, while tendon modulus decreased after both one and two tendon tears. Additionally, the remaining (intact) tendon cross-sectional areas continued to increase with time post-injury. These alterations could potentially lead to further tendon damage and tear progression.
Few case reports have described the surgical treatment of calcifying tendonitis of the subscapularis tendon. We present a case of symptomatic diffuse calcifying tendonitis involving the subscapularis and infraspinatus insertions that was difficult to detect arthroscopically. The patient was treated with arthroscopic incision of the tendinous insertions thorough removal of the calcific deposits and subsequent repair using a suture-anchor technique. Two years after the surgical procedure, the patient was completely pain-free and attained full range of motion. Radiographic evaluation performed 2 years after the procedure revealed no calcific deposits. We conclude that the combination of incision of the subscapularis and infraspinatus insertions, complete removal of the calcific deposits, and subsequent suture-anchor repair in an all-arthroscopic manner can lead to an excellent clinical outcome without compromising the functional integrity of the rotator cuff tendons.
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.
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.
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.
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.
Double-row; glenohumeral joint; rotator cuff; single-row; suture anchor repair
For the past few decades, the repair of rotator cuff tears has evolved significantly with advances in arthroscopy techniques, suture anchors and instrumentation. From the biomechanical perspective, the focus in arthroscopic repair has been on increasing fixation strength and restoration of the footprint contact characteristics to provide early rehabilitation and improve healing. To accomplish these objectives, various repair strategies and construct configurations have been developed for rotator cuff repair with the understanding that many factors contribute to the structural integrity of the repaired construct. These include repaired rotator cuff tendon-footprint motion, increased tendon-footprint contact area and pressure, and tissue quality of tendon and bone. In addition, the healing response may be compromised by intrinsic factors such as decreased vascularity, hypoxia, and fibrocartilaginous changes or aforementioned extrinsic compression factors. Furthermore, it is well documented that torn rotator cuff muscles have a tendency to atrophy and become subject to fatty infiltration which may affect the longevity of the repair. Despite all the aforementioned factors, initial fixation strength is an essential consideration in optimizing rotator cuff repair. Therefore, numerous biomechanical studies have focused on elucidating the strongest devices, knots, and repair configurations to improve contact characteristics for rotator cuff repair. In this review, the biomechanical concepts behind current rotator cuff repair techniques will be reviewed and discussed.
Rotator cuff repair; Load to failure; Biomechanics; Transosseous-equivalent
Surgical repair of massive rotator cuff tears is associated with less favorable clinical results and a higher retear rate than repair of smaller tears, which is attributed to irreversible degenerative changes of the musculotendinous unit.
Materials and Methods:
During the study period, 25 consecutive patients with a massive rotator cuff tear were enrolled in the study and the tears were repaired with an open suture anchor repair technique. Preoperative and postoperative clinical assessments were performed with the Constant score, the simple shoulder test (SST) and a pain visual analog scale (VAS). At the final follow-up, rotator cuff strength measurement was evaluated and assessment of tendon integrity, fatty degeneration and muscle atrophy was done using a standardized magnetic resonance imaging protocol.
The mean follow-up period was 70 months. The mean constant score improved significantly from 42.3 to 73.1 points at the final follow-up. Both the SST and the pain VAS improved significantly from 5.3 to 10.2 points and from 6.3 to 2.1, respectively. The overall retear rate was 44% after 6 years. Patients with an intact repair had better shoulder scores and rotator cuff strength than those with a failed repair, and also the retear group showed a significant clinical improvement (each P<0.05). Rotator cuff strength in all testing positions was significantly reduced for the operated compared to the contralateral shoulder. Muscle atrophy and fatty infiltration of the rotator cuff muscles did not recover in intact repairs, whereas both parameters progressed in retorn cuffs.
Open repair of massive rotator tears achieved high patient satisfaction and a good clinical outcome at the long-term follow-up despite a high retear rate. Also, shoulders with retorn cuffs were significantly improved by the procedure. Muscle atrophy and fatty muscle degeneration could not be reversed after repair and rotator cuff strength still did not equal that of the contralateral shoulder after 6 years.
Level of evidence:
Magnetic resonance imaging; massive rotator cuff tear; open rotator cuff repair; rotator cuff strength; subscapularis function
The purpose of this systematic review was to address the treatment of rotator cuff tears by applying tissue engineering approaches to improve tendon healing, specifically platelet rich plasma (PRP) augmentation, stem cells, and scaffolds. Our systematic search was performed using the combination of the following terms: “rotator cuff”, “shoulder”, “PRP”, “platelet rich plasma”, “stemcells”, “scaffold”, “growth factors”, and “tissue engineering”. No level I or II studies were found on the use of scaffolds and stem cells for rotator cuff repair. Three studies compared rotator cuff repair with or without PRP augmentation. All authors performed arthroscopic rotator cuff repair with different techniques of suture anchor fixation and different PRP augmentation. The three studies found no difference in clinical rating scales and functional outcomes between PRP and control groups. Only one study showed clinical statistically significant difference between the two groups at the 3-month follow up. Any statistically significant difference in the rates of tendon rerupture between the control group and the PRP group was found using the magnetic resonance imaging. The current literature on tissue engineering application for rotator cuff repair is scanty. Comparative studies included in this review suggest that PRP augmented repair of a rotator cuff does not yield improved functional and clinical outcome compared with non-augmented repair at a medium and long-term followup.
A rotator cuff tear causes morphologic changes in rotator cuff muscles and tendons and reduced shoulder strength. The mechanisms by which these changes affect joint strength are not understood. This study’s purpose was to empirically determine rotation moment arms for subregions of supraspinatus, infraspinatus, and for teres minor, and to test the hypothesis that subregions of the cuff tendons increase their effective moment arms through connections to other subregions. Tendon excursions were measured for full ranges of rotation on 10 independent glenohumeral specimens with the humerus abducted in the scapular plane at 10 and 60°. Supraspinatus and infraspinatus tendons were divided into equal width subregions. Two conditions were tested: tendon divided to the musculotendinous junction, and tendon divided to the insertion on the humerus. Moment arms were determined from tendon excursion via the principle of virtual work. Moment arms for the infraspinatus (p < 0.001) and supraspinatus (p < 0.001) were significantly greater when the tendon was only divided to the musculotendinous junction versus division to the humeral head. Moment arms across subregions of infraspinatus (p < 0.001) and supraspinatus (p < 0.001) were significantly different. A difference in teres minor moment arm was not found for the two cuff tendon conditions. Moment arm differences between muscle subregions and for tendon division conditions have clinical implications. Interaction between cuff regions could explain why some subjects retain strength after a small cuff tear. This finding helps explain why a partial cuff repair may be beneficial when a complete repair is not possible. Data presented here can help differentiate between cuff tear cases that would benefit from cuff repair and cases for which cuff repair might not be as favorable.
shoulder; external rotation; moment arm; infraspinatus; teres minor; supraspinatus
Rotator cuff tears are disabling conditions that result in joint loading changes and functional deficiencies. Clinically, damage to the long-head of the biceps tendon has been found in conjunction with rotator cuff tears and this damage is thought to increase with increasing rotator cuff tear size. Despite its importance, controversy exists regarding the optimal treatment for the biceps. An animal model of this condition would allow for controlled studies to investigate the etiology of this problem and potential treatment strategies. We created rotator cuff tears in the rat model by detaching single (supraspinatus) and multiple (supraspinatus+infraspinatus or supraspinatus+subscapularis) rotator cuff tendons and measured the mechanical properties along the length of the long-head of the biceps tendon four and eight weeks following injury. Area of the biceps was increased in the presence of a single rotator cuff tendon tear (by ~150%), with a greater increase in the presence of a multiple rotator cuff tendon tear (by up to 220%). Modulus values decreased as much as 43% and 56% with one and two tendon tears, respectively. Also, multiple tendon tear conditions involving the infraspinatus in addition to the supraspinatus affected the biceps tendon more than those involving the subscapularis and supraspinatus. Finally, biceps tendon mechanical properties worsened over time in multiple rotator cuff tendon tears. Therefore, the rat model correlates well with clinical findings of biceps tendon pathology in the presence of rotator cuff tears and can be used to evaluate etiology and treatment modalities.
Surgically repaired rotator cuff repairs may re-tear in the post-operative follow-up phase, and periodic imaging is useful for early detection. The authors describe a simple surgical technique that provides a visible clue to the tendon edge on an anteroposterior radiograph of the shoulder. The technique involves arthroscopic or mini-open radio-opaque tagging of the tendon edge using a metal marker, and followed by a double-row rotator cuff repair using suture anchors. Serial post-operative radiographs may then be used to monitor the position of the marker. Progressive or marked displacement of the marker suggests a failure of cuff repair integrity and should be evaluated further.
Arthroscopic repair; double-row repair; rotator cuff; shoulder surgery
Latissimus dorsi transfer is a well-established method for the treatment of posterosuperior massive irreparable rotator cuff tears. We propose using an arthroscopically assisted technique that avoids insult to the deltoid. With the patient in the lateral decubitus position, an L-shaped incision is made along the anterior belly of the latissimus muscle and then along the posterior axillary line. The latissimus and teres major are identified and separated. The tendon insertion of the latissimus is isolated, and a FiberWire traction suture (Arthrex, Naples, FL) is placed, facilitating dissection of the muscle to the thoracodorsal neurovascular pedicle and subsequent mobilization. The interval deep to the deltoid and superficial to the teres minor is developed into a subdeltoid tunnel for arthroscopic tendon transfer. The latissimus tendon is then transferred and stabilized arthroscopically to the lateral aspect of the infraspinatus and supraspinatus footprints by multiple suture anchors.
Biodegradable implants lead to problems such as cyst formation, soft-tissue inflammation, loose implant fragments or local osteolysis. This report represents the first published case of an intraosseous foreign body granuloma in the humeral head after arthroscopic rotator cuff tear fixation with a poly-l-lactide (PLLA) suture anchor. A 48-year-old female patient presented with pain in her right shoulder. A refixation of her right supraspinatus tendon with a biodegradable suture anchor was performed 11 months ago at an external hospital. Laboratory tests showed normal values for C-reactive protein, leukocytes and the erythrocyte sedimentation rate. No signs of infection or instability were noted. The visual analogue scale (VAS) was 8, the simple shoulder test (SST) was 4 and the American shoulder and elbow surgeons score (ASES) was 44. Plain radiographs showed high lucency in the area of the tuberculum majus. MRI showed an intra- and extraosseous mass surrounded by fluid in this area. Surgical care involved arthroscopic debridement and removal of the suture anchor. Histological examination revealed a foreign body granuloma. At the 18-month follow-up the patient was nearly pain-free. The VAS was 2, SST was 10 and ASES was 88. Foreign body granulomas are a well known but rarely described complication that arises after the use of biodegradable suture anchors in shoulder surgery. Every patient presenting with shoulder pain after usage of a biodegradable fixation material should be evaluated closely. Orthopaedic surgeons should be aware of the possibility of delayed foreign body reactions, especially after using PLLA anchors.
Foreign body granuloma; Bioabsorbable; Suture anchor; Shoulder; Rotator cuff tear
A common distal radio-ulnar joint (DRUJ) stabilisation procedure uses a tendon graft running from the lip of the radial sigmoid notch to the ulnar fovea and through a bony tunnel to the ulnar shaft, before being wrapped round the distal ulna and sutured to itself. Such graft fixation can be challenging and requires a considerable tendon length. The graft length could be reduced by fixing the graft to the ulna using a bone anchor or interference screw. The aim of this study was to compare the strength of three distal ulna graft fixation methods (tendon wrapping and suturing, bone anchor and interference screw). Four human cadaveric ulnae were used. A tendon strip was run through a tunnel in the distal ulna and secured by: (1) wrapping round the shaft and suturing it to itself, (2) a bone anchor and (3) an interference screw in the bone tunnel. Load to failure was determined using a custom-made apparatus and an Instron machine. Maximum failure load was highest for the bone anchor fixation (99.3 ± 23.7 N) followed by the suturing (96.2 ± 12.1 N), and the interference screw fixation (46.9 ± 5.6 N). There was no significant difference between the tendon suturing and bone anchor methods, but the tendon suturing was statistically significantly higher compared to the interference screw (P = 0.028). In performing anatomical stabilisation of the DRUJ fixation of the tendon graft to the distal ulna with a bone anchor provides the most secure fixation. This may make the stabilisation technique less demanding and require a smaller tendon graft.
DRUJ; Wrist instability; Tenodesis; Interference screw
Arthroscopic repair of the rotator cuff is a demanding surgery. Accurate placement of anchors is key to success.
A 38-year-old woman received arthroscopic repair of her rotator cuff using a double row suture anchor technique. Postoperatively, she developed impingement syndrome which resulted from vertical displacement of a suture anchor once the shoulder was mobilised. The anchor was removed eight weeks following initial surgery and the patient had an uneventful recovery.
Impingement syndrome following arthroscopic repair of the rotator cuffs using double row suture anchor has not been widely reported. This is the first such case where anchoring has resulted in impingement syndrome.
Biceps tenodesis techniques can use a large-caliber interference screw, a suture anchor, or a knotless anchor. This report describes a tenodesis technique that is easy to perform and does not require any knotting. Before penetration of the tendon with the tip, a No. 2 nonabsorbable braided suture is passed through the lumen of the hook-like instrument. The use of only 1 hooking maneuver through the tendon can allow the winding of the whole tendon. The eyelet of a knotless anchor (Bio-PushLock; Arthrex, Naples, FL) with 2 ends of the suture is inserted into the bone hole at the bicipital groove.
We present a simple technique of arthroscopic rotator cuff repair using a spinal needle and suture loop.
With the arthroscope laterally, a spinal needle looped with PDS is inserted percutaneously into the shoulder posteriorly and penetrated through the healthy posterior cuff tear margin. Anteriorly, another spinal needle loaded with PDS is inserted percutaneously to engage the healthy tissue at the anterior tear margin. The suture in the anterior needle is then delivered into the suture loop of the posterior needle using a suture retriever. The posterior needle and loop are then pulled out carrying the anterior suture with it. The two limbs of this suture are then retrieved through a cannula for knotting. The same procedure is then repeated for additional suturing. Suture anchors placed over the greater tuberosity are used to complete the repair.
This is an easy method of rotator cuff repair using simple instruments and lesser time, hence can be employed at centers with less equipment and at reduced cost to the patient.
Surgical repair of symptomatic, retracted rotator cuff tears unresponsive to non-operative treatments requires closure of the tear without undue tension and reattaching the torn tendon to its former insertion site. In this study, the length of the torn tendon edge was hypothesized to be longer than the length of the humeral insertion site. The objective of this study was to quantify the discrepancy in length of the torn tendon edge and the length of the avulsed humeral insertion site.
Materials and methods
Full thickness, rotator cuff tears that were found in twelve fresh frozen cadaver shoulders was studied. The length of the torn tendon edge, the length of the avulsed humeral insertion site and the retraction were measured using digital calipers.
Each tear involved the supraspinatus and the infraspinatus was additionally torn in six. The size of the tear was medium in eight and large in four. The length of the torn tendon edge was always longer than the length of the avulsed humeral insertion site. Retraction was 29.9 ± 9.3 mm (range 21–48 mm). The repair ratio, defined as the ratio of length of torn tendon edge to the length of avulsed humeral insertion site, was 2.6 ± 0.4 (range 2.1–3.5).
As only the length of the torn tendon edge equal to the length of the avulsed humeral insertion site can be repaired to bone, a repair ratio more than one precludes a simple repair and an additional repair technique such as margin convergence would be necessary for the remaining unapproximated torn tendon edge in rotator cuff tears. Repair ratio may aid in selection of the surgical repair technique of these rotator cuff tears.
Rotator cuff tear; Repair; Retraction; Insertion
Failure of suture anchor fixation in rotator cuff repair can occur at different interfaces. Prior studies show fixation at the bone-anchor interface can be augmented using polymethylmethacrylate (PMMA) cement, and screw fixation into bone can be strengthened using bioabsorbable tricalcium phosphate cement.
We wished to determine whether augmentation of suture anchor fixation using bioabsorbable tricalcium phosphate cement would increase pullout strength of suture anchors from bone and the number of cycles to failure, to determine the mode of failure after cement augmentation, and to compare strength and mode of failure with those after augmentation with PMMA.
We used 10 matched pairs of cadaveric proximal humeri and implanted a metal screw-type suture anchor in one side and on the other side injected tricalcium phosphate cement into the anchor holes before anchor placement. We tested all specimens to failure using a ramped cyclic loading protocol.
Tricalcium phosphate cement augmentation increased the final load to failure by 29% and the number of cycles to failure by 20%. Visual inspection confirmed that failure occurred at the cement-bone interface.
Tricalcium phosphate cement appears to augment suture anchor fixation into bone, reducing the risk of anchor pullout and failure.
When relying on suture anchor fixation in bone of questionable quality, we suggest considering augmentation of suture anchor fixation with bioabsorbable cement. This method also provides potential for bioabsorbability and may be more amenable to arthroscopic application.
With advancements in arthroscopic surgery, arthroscopic biceps tenodesis with suture anchor recently has been reported to be a reasonable option for the treatment of biceps pathologies, especially for those that are symptomatic or accompanied by a rotator cuff tear. We introduce our technique of arthroscopic biceps tenodesis with suture anchor that we call the loop-suture technique, which is constructed with 1 loop strand and another sutured strand. This technique can help to improve biceps grip and simultaneously minimize longitudinal splitting of the tendon. In addition, it is relatively simple and can be performed with the use of conventional devices and arthroscopic portals used for rotator cuff repair, without the formation of additional portals or a separate incision for the tenodesis.
Background and purpose The New Zealand white rabbit subscapularis tendon passes under a bony arch to insert on the lesser tubercle of the humerus in a manner analogous to the supraspinatus tendon in humans. We assessed whether this unique anatomy may provide a new animal model of the shoulder to improve our understanding of rotator cuff pathology.
Methods The dimensions of the rotator cuff insertions (subscapularis, supraspinatus, and infraspinatus) were measured on 10 fresh frozen cadaveric New Zealand white rabbit shoulders. Mechanical testing was performed on 8 fresh frozen subscapularis insertions (4 matched pairs). Video analysis of the gait cycle was performed on 2 live animals.
Results The origins, insertions, and innervations of the rabbit rotator cuff musculature are analogous to those in humans. However, the rabbit acromion is a rudimentary structure with only the infraspinatus and teres minor muscles passing beneath. Furthermore, at the point where the infraspinatus passes under the arch, it is muscular rather than tendinous. The anterior aspect of the glenohumeral joint contains an additional bony tunnel with its boundaries being the tuberculum supraglenoidale laterally, the coracoideus process superiorly, the tuberculum infraglenoidale inferiorly, and the coracobrachialis muscle medially. The origin of the rabbit subscapularis muscle resides on the anterior scapula. The subscapularis tendon then traverses this bony tunnel prior to its insertion on the lesser tubercle of the humerus. Video analysis and anatomic dissections confirmed excursion of the subscapularis tendon within this bony tunnel throughout the gait cycle. The subscapularis footprint on the proximal humerus measured 6.8 mm (SD 0.29) × 2.5 mm (SD 0.17). Mechanical testing of the subscapularis tendon showed the stiffness to range from 57 to 117 N/mm (SD 23). Ultimate yield ranged from 88 to 215 N (SD 518). The elastic modulus of the rabbit tendon was 56 MPa. 6 of the 8 subscapularis tendons failed at the tendon mid-substance; the other 2 failed at the bony insertion.
Interpretation The unique anatomic architecture and the mechanical characteristics of the rabbit subscapularis muscle provide an opportunity to improve our understanding of rotator cuff pathology.
Although the incidence of partial-thickness rotator cuff tears (PTRCTs) was reported to be from 13% to 32% in cadaveric studies, the actual incidence is not yet known. The causes of PTRCTs can be explained by either extrinsic or intrinsic theories. Studies suggest that intrinsic degeneration within the rotator cuff is the principal factor in the pathogenesis of rotator cuff tears. Extrinsic causes include subacromial impingement, acute traumatic events, and repetitive microtrauma. However, acromially initiated rotator cuff pathology does not occur and extrinsic impingement does not cause pathology on the articular side of the tendon. An arthroscopic classification system has been developed based on the location and depth of the tear. These include the articular, bursal, and intratendinous areas. Both ultrasound and magnetic resonance image are reported with a high accuracy of 87%. Conservative treatment, such as subacromial or intra-articular injections and suprascapular nerve block with or without block of the articular branches of the circumflex nerve, should be considered prior to operative treatment for PTRCTs.
injections; intrinsic; nerve block; rotator cuff
The purpose of the present study is to describe the technique of margin convergence for U-shaped rotator cuff tears and report the clinical outcomes and ultrasonography with a minimum of 2 years follow-up. Three hundred eleven patients with a rotator cuff tear were prospectively enrolled in a registry at one institution. Inclusion criteria included any patient undergoing arthroscopic margin convergence for a rotator cuff tear. Exclusion criteria included open or mini-open rotator cuff repairs or suture anchor fixation to the cuff insertion without margin convergence. The outcome measurements included physical examination, manual muscle testing, the American Shoulder and Elbow Surgeons (ASES) score, and ultrasonography. Nineteen patients met the study criteria and 13 were available for 2-year follow-up (68.4%). The mean age of this cohort was 62.2 ± 7.5 years with a mean pre-operative rotator cuff tear size of 4.0 ± 1.6 cm. The ASES score increased significantly from 50.0 ± 17.7 before surgery to 83.3 ± 19.5 at 2 years (P = 0.01). The active forward elevation also improved from 156.2 ± 11.9° before surgery to 168.0 ± 12.1 at 2 years (P = 0.03). The active external rotation 54.4 ± 14.5 at baseline and improved to 57.1 ± 19.1 at 2 years (P = 0.04). The strength also increased significantly from 6.7 ± 6.4 to 10.6 ± 4.9 lb at 1 year (P = 0.048). The post-operative ultrasound demonstrated that 46.2% of rotator cuff tears were healed at 2 years. In conclusion, margin convergence is a useful technique for U-shaped tears that are difficult to mobilize.
margin convergence; rotator cuff; shoulder arthroscopy