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

Anteroposterior tear size, age, hospital, and case number are important predictors of repair integrity: an analysis of 1962 consecutive arthroscopic single-row rotator cuff repairs

BACKGROUND

Retear or nonhealing of a surgically repaired rotator cuff is common, but the determinants of retear are poorly understood. We aimed to determine the relationship between preoperative and intraoperative factors and retear rate following rotator cuff repair and to formulate a predictive model based on this relationship, including any interaction effects between tear size, patient age, and surgical experience in contributing to the retear rate.

METHODS

We performed a post hoc analysis of prospectively collected data from 1962 consecutive patients who underwent a primary arthroscopic single-row rotator cuff repair performed by the senior author from 2007 through 2018 and postoperatively returned for 6-month follow-up ultrasonography.

RESULTS

Multiple logistic regression analysis revealed anteroposterior tear length to be the most important independent predictor of retear (Wald statistic, 90; P < .001). Other independent predictors included case number (Wald statistic, 59; P < .001), patient age at surgery (Wald statistic, 30; P < .001), and type of hospital (public vs. private) (Wald statistic, 17; P < .001). The data indicated that following rotator cuff repair, there was a 4-fold increase in the retear rate as the anteroposterior tear size increased from 1 cm to 3 cm; a 8-fold decrease when comparing case number 1000 with case number 3000; a 2-fold increase as patient age increased from 50 years to 70 years; and a 3-fold increase when comparing surgery performed in a public hospital vs. a private hospital. The area under the receiver operating characteristic curve was 0.81 (95% confidence interval, 0.78-0.84), indicating that our equation could predict 81% of retears.

CONCLUSIONS

Anteroposterior tear length was the most important independent predictor of retear or nonhealing. Other predictive factors included case number, patient age at surgery, and hospital type. The predictive effect of anteroposterior tear length, patient age, and case number in contributing to retear was additive. Our regression equation may be used to calculate patient rotator cuff retear risk at 6 months after repair.

Clinical and functional outcomes of a novel transosseous device to treat rotator cuff tears: A minimum 2-year follow-up

PURPOSE

Despite the improvements in the repair equipment techniques of rotator cuff, a gold standard method has not been defined yet and transosseous fixation through deltoid-splitting (mini-open) approach is still regarded as a good option. The primary purpose of this study is to present satisfactory clinical and functional outcomes with a novel transosseous device in full-thickness rotator cuff tear through deltoid-splitting.

MATERIALS AND METHODS

This retrospective study was performed on 70 consecutive patients who underwent surgery by a single surgeon from June 2014 to June 2016 for a full-thickness rotator cuff tear and was managed with a novel transosseous device. Total number of patients, mean age, percentage of male and female patients, mean duration of follow-up, percentage of involvement of the dominant extremity, affected shoulder, and tear size were recorded. Functional and clinical outcomes were assessed baseline and postoperatively at 3 and 6 months and final follow-up using Disabilities of the Arm, Shoulder and Hand (Q-DASH) and Constant-Murley scores.

RESULTS

A total of 70 (49 (70%) female, 21 (30%) male) patients whose mean age was 58.66 ± 9.19 (38-77) years were included. The mean surgery time was 35.33 ± 5.34 (28-55) min. The mean follow-up time was 28.31 ± 3.03 (24-36) months. According to the DeOrio and Cofield classification, 15 (21.43%) tears were small, 33 (47.14%) medium, 16 (22.86%) large, and 6 (8.57%) massive. By the final follow-up, the mean Constant-Murley score had significantly improved from 27.67 ± 7.46 (13-41) to 81.25 ± 3.77 (74-87; p = 0.0001) and the Q-DASH score had decreased from 82.34 ± 10.37 (65.91-100) to 10.28 ± 6.88 (0-23.45; p = 0.0001). There were no significant differences in the Constant-Murley or Q-DASH score at baseline-final follow-up between the small, medium, large, and massive tear groups (p > 0.05).

CONCLUSIONS

Treatment of full-thickness rotator cuff tear using this novel transosseous device significantly improved functional and clinical scores. However, further long-term prospective randomized multicenter trials involving comparative studies are necessary to confirm these findings.

Biomechanical Strength of Rotator Cuff Repairs: A Systematic Review and Meta-regression Analysis of Cadaveric Studies

BACKGROUND

Biomechanical cadaveric studies of rotator cuff repair (RCR) have shown that transosseous equivalent and double-row anchored repairs are stronger than other repair constructs.

PURPOSE

To identify technical and procedural parameters that most reliably predict biomechanical performance of RCR constructs.

STUDY DESIGN

Systematic review.

METHODS

The authors systematically searched the EMBASE and PubMed databases for biomechanical studies that measured RCR performance in cadaveric specimens. The authors performed a meta-regression on the pooled data set with study outcomes (gap formation, failure mode, and ultimate failure load) as dependent variables and procedural parameters (eg, construct type, number of suture limbs) as covariates. Stratification by covariates was performed. An alpha level of .05 was used.

RESULTS

Data from 40 eligible studies were included. Higher number of suture limbs correlated with higher ultimate failure load (β = 38 N per limb; 95% CI, 28 to 49 N) and less gap formation (β = -0.6 mm per limb; 95% CI, -1 to -0.2 mm). Other positive predictors of ultimate failure load were number of sutures, number of mattress stitches, and use of wide suture versus standard suture. When controlling for number of suture limbs, we found no significant differences among single-row anchored, double-row anchored, transosseous equivalent, and transosseous repairs. Higher number of suture limbs and transosseous equivalent repair both increased the probability of catastrophic construct failure.

CONCLUSION

This study suggests that the number of sutures, suture limbs, and mattress stitches in a RCR construct are stronger predictors of overall strength than is construct type. There is a need to balance increased construct strength with higher risk of type 2 failure.

The use of suture-tape and suture-wire in arthroscopic rotator cuff repair: A comparative biomechanics study

BACKGROUND

Rotator cuff repair surgery aims to create a secure, pressurized tendon-bone footprint to permit re-establishment of the fibrovascular interface and tendon healing. Flat-braided suture-tape is an alternative suture material to traditional suture-wire that has potential to reproduce a larger repair construct contact area. The objective of this study was to compare contact pressure, area as well as the mechanical fatigue strength between suture-wire and suture-tape Suture-bridge repair constructs in an ovine model.

METHODS

Sixty lamb infraspinatus tendons were harvested and randomly allocated to three- and four-anchor Suture-bridge repairs performed using either suture-wire or suture-tape. Thirty-two specimens were cyclically loaded for 200 cycles in an Instron testing machine, while tendon gap formation was recorded using a high speed digital motion analysis system. Loading to failure was then performed to evaluate construct ultimate tensile strength and stiffness. The remaining 28 specimens were assessed for repair contact pressure and area using pressure-sensitive film.

RESULTS

There was a significantly greater average tendon contact pressure (mean difference: 0.064 MPa, p = 0.04) and area (mean difference: 2.71 mm², p = 0.03) in fiber-tape repair constructs compared to those in fiber-wire constructs for the three-anchor Suture-bridge configuration. The four-anchor suture-tape constructs had a significantly larger ultimate tensile strength than that of the four-anchor suture-wire constructs (mean difference: 56.4 N, p = 0.04). There were no significant differences in gap formation or stiffness between suture-tape and suture-wire constructs (p > 0.05).

CONCLUSION

Suture-tape offers greater pressurised tendon-bone contact than suture-wire in three-anchor Suture-bridge repairs, while greater mechanical strength is achieved with the use of suture-tape in four-anchor Suture-bridge constructs.

Functional and Radiographic Outcomes After Arthroscopic Transosseous Suture Repair of Medium Sized Rotator Cuff Tears

PURPOSE

To evaluate the functional and anatomical outcomes after arthroscopic transosseous suture (TOS) repair of 2 to 4 cm sized rotator cuff tears and to identify preoperative factors influencing repair failure.

METHODS

From May 2013 to August 2014, patients with symptomatic 2 to 4 cm full-thickness tears underwent arthroscopic TOS repair, and those who could be followed up for a minimum of 2 years were included in this retrospective study. Functional and anatomical outcomes were analyzed up to 2 years postoperatively. Factors affecting cuff repair failure were evaluated, using both univariate and multivariate analyses.

RESULTS

Twenty-seven patients were included. On preoperative magnetic resonance imaging data, the mean anteroposterior dimension tear size was 27.0 ± 3.3 mm and mean retraction was 30.7 ± 3.1 mm. Anatomic failure (Sugaya III, IV, and V) rate was 33% with arthroscopic TOS repair; however, significant improvements were found regardless of cuff healing. Mean American Shoulder and Elbow Surgeons score (range, 0-100) improved from 48.8 ± 16.6 preoperatively to 80.1 ± 11.1 postoperatively (P < .001), mean Constant score (range, 0-100) improved from 54.5 ± 11.8 to 73.7 ± 8.5 (P < .001), and mean pain visual analog scale score (range, 0-10) improved from 3.9 ± 1.7 to 2.0 ± 1.1 (P < .001). These changes reached each minimal clinically important difference previously reported. Greater tear size in anteroposterior dimension (P = .034), decreased acromiohumeral distance (P = .022), and higher fatty infiltration of supraspinatus (P = .011) were independent preoperative factors associated with repair failure. Twelve patients (44%) experienced intraoperative bone laceration.

CONCLUSIONS

Arthroscopic TOS repair was a reliable technique for patients with 2 to 4 cm size rotator cuff tear. Preoperative factors associated with cuff repair failure were greater tear size in anteroposterior dimension, decreased acromiohumeral distance, and higher fatty infiltration of supraspinatus.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Advantages of Arthroscopic Rotator Cuff Repair With a Transosseous Suture Technique: A Prospective Randomized Controlled Trial

BACKGROUND

Rotator cuff tear is a common finding in patients with painful, poorly functioning shoulders. The surgical management of this disorder has improved greatly and can now be fully arthroscopic.

PURPOSE

To evaluate clinical and radiological results of arthroscopic rotator cuff repair using 2 different techniques: single-row anchor fixation versus transosseous hardware-free suture repair.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Sixty-nine patients with rotator cuff tears were enrolled: 35 patients were operated with metal anchors and 34 with standardized transosseous repair. The patients were clinically evaluated before surgery, during the 28 days after surgery, and at least 1 year after the operation by the use of validated rating scores (Constant score, QuickDASH, and numerical rating scale [NRS]). Final follow-up was obtained at more than 3 years by a QuickDASH evaluation to detect any difference from the previous follow-up. During the follow-up, rotator cuff integrity was determined through magnetic resonance imaging and was classified according to the 5 Sugaya categories.

RESULTS

Patients operated with the transosseous technique had significantly less pain, especially from the 15th postoperative day: In the third week, the mean NRS value for the anchor group was 3.00 while that for transosseous group was 2.46 ( P = .02); in the fourth week, the values were 2.44 and 1.76, respectively ( P < .01). No differences in functional outcome were noted between the 2 groups at the final evaluation. In the evaluation of rotator cuff repair integrity, based on Sugaya magnetic resonance imaging classification, no significant difference was found between the 2 techniques in terms of retear rate ( P = .81).

CONCLUSION

No significant differences were found between the 2 arthroscopic repair techniques in terms of functional and radiological results. However, postoperative pain decreased more quickly after the transosseous procedure, which therefore emerges as a possible improvement in the surgical repair of the rotator cuff. Registration: NCT01815177 ( ClinicalTrials.gov identifier).

Icariin Promotes Tendon-Bone Healing during Repair of Rotator Cuff Tears: A Biomechanical and Histological Study

To investigate whether the systematic administration of icariin (ICA) promotes tendon-bone healing after rotator cuff reconstruction in vivo, a total of 64 male Sprague Dawley rats were used in a rotator cuff injury model and underwent rotator cuff reconstruction (bone tunnel suture fixation). Rats from the ICA group (n = 32) were gavage-fed daily with ICA at 0.125 mg/g, while rats in the control group (n = 32) received saline only. Micro-computed tomography, biomechanical tests, serum ELISA (calcium; Ca, alkaline phosphatase; AP, osteocalcin; OCN) and histological examinations (Safranin O and Fast Green staining, type I, II and III collagen (Col1, Col2, and Col3), CD31, and vascular endothelial growth factor (VEGF)) were analyzed two and four weeks after surgery. In the ICA group, the serum levels of AP and OCN were higher than in the control group. More Col1-, Col2-, CD31-, and VEGF-positive cells, together with a greater degree of osteogenesis, were detected in the ICA group compared with the control group. During mechanical testing, the ICA group showed a significantly higher ultimate failure load than the control group at both two and four weeks. Our results indicate that the systematic administration of ICA could promote angiogenesis and tendon-bone healing after rotator cuff reconstruction, with superior mechanical strength compared with the controls. Treatment for rotator cuff injury using systematically-administered ICA could be a promising strategy.

Healing disturbance with suture bridge configuration repair in rabbit rotator cuff tear

BACKGROUND

Medial row failure has been reported in the suture bridge technique of rotator cuff repair. This study compared the healing response of suture bridge configuration repair (SBCR) and parallel type transosseous repair (PTR).

METHODS

Acute rotator cuff repair was performed in 32 rabbits. Both shoulders were repaired using PTR or SBCR. In PTR, simple PTR was performed through 2 parallel transosseous tunnels created using a microdrill. In SBCR, 2 additional crisscross transosseous tunnels were added to mimic arthroscopic SBCR. At 1, 2, and 5 weeks postoperatively, comparative biomechanical testing was performed in 8 rabbits, and histologic analysis, including immunohistochemical staining for CD31, was performed in 4 rabbits.

RESULTS

Failure loads at 1 week (38.12 ± 20.43 N vs 52.00 ± 27.23 N; P = .284) and 5 weeks (97.93 ± 48.35 N vs 119.60 ± 60.81 N; P = .218) were not statistically different between the SBCR and PTR groups, respectively, but were significantly lower in the SBCR group than in the PTR group (23.56 ± 13.56 N vs. 44.25 ± 12.53 N; P = .009), respectively, at 2 weeks. Markedly greater fibrinoid deposition was observed in the SBCR group than in the PTR group at 2 weeks. For vascularization, there was a tendency that more vessels could be observed in PTR than in SBCR at 2 weeks (15.9 vs 5.6, P = .068).

CONCLUSIONS

In a rabbit acute rotator cuff repair model, SBCR exhibited inferior mechanical strength, and fewer blood vessels were observed at the healing site at 2 weeks postoperatively. Medial row tendon failure was more common in SBCR. Surgeons should consider the clinical effect of SBCR when performing rotator cuff repair.

Arthroscopic transosseous rotator cuff repair: technical note, outcomes, and complications

The goal of this study was to review the authors' initial experience with arthroscopic transosseous rotator cuff repair. Thirty-one patients with full-thickness rotator cuff tears underwent arthroscopic transosseous rotator cuff repair over a 15-month period. Preoperatively, demographics and subjective scores were recorded. Postoperatively, pain levels, subjective shoulder values, satisfaction scores, American Shoulder and Elbow Surgeons (ASES) scores, complications, and reoperations were noted with a minimum 2-year follow-up. The relationships between pre- and intraoperative variables and outcome scores were determined with univariate analysis. Average patient age was 56 years, and 23 patients (74%) were men. Twenty patients (65%) underwent primary rotator cuff repair, and 11 patients (35%) underwent revision repair. Average time to follow-up was 26 months. Average preoperative pain level and subjective shoulder value were 5.1 of 10 and 35%, respectively. Average postoperative scores included pain level of 0.9 of 10, subjective shoulder value of 84%, satisfaction score of 90.6 of 100, and ASES score of 86.3 of 100. There were 3 (9.7%) major and 2 (6%) minor complications. Patients undergoing revision rotator cuff repair had significantly worse outcomes (pain level, subjective shoulder value, ASES score; P<.05) compared with those undergoing primary repair, and cortical augmentation did not significantly affect outcome. Overall, outcomes after arthroscopic transosseous rotator cuff repair are good, although patients undergoing revision repair do not have the same outcomes as those undergoing primary cuff repair. The procedure is not without complications (9.7% major, 6% minor complications). Cortical augmentation may be used to supplement fixation, although it does not necessarily affect outcomes. Patients without such augmentation may be at increased risk for suture cutout through the bone.

A hierarchical, stretchable and stiff fibrous biotemplate engineered using stagger-electrospinning for augmentation of rotator cuff tendon-healing

The regeneration of fibrocartilage at the tendon-bone insertion site in rotator cuff tears (RCTs) is challenging due to the complexity of its composition and mechanical properties. In this study, hierarchical, stretchable and stiff fibrous scaffolds composed of microfibers of poly(ε-caprolactone) (PCL) and nanofibers of chitosan (CS) were fabricated using stagger-electrospinning for the augmentation of RCT-healing. It was found that the composite PCL-CS scaffolds had significantly improved strength and failure strain compared to the control CS scaffolds and increased stiffness compared to the control PCL scaffolds. These scaffolds also showed enhanced hydrophilicity, water absorption and a faster degradation rate compared to the PCL scaffolds. Moreover, they demonstrated better fibroblast attachment and proliferation compared to the PCL scaffolds. Radiological and histological analysis revealed that the PCL-CS scaffolds enhanced new bone formation (mineralization) and collagen and glycosaminoglycan expression (major components of extracellular matrix) compared to the PCL scaffolds. Furthermore, the torn tissues at the tendon-bone insertion site regenerated with the PCL-CS scaffolds showed higher strength and failure strain as well as stiffness compared to those repaired using only the PCL scaffolds. The above mentioned results suggest that the hierarchical, stretchable and stiff fibrous scaffolds engineered using stagger-electrospinning have great potential for the augmentation of RCT-healing.

Effect of the Interposition of Calcium Phosphate Materials on Tendon-Bone Healing During Repair of Chronic Rotator Cuff Tear

BACKGROUND

The current nature of tendon-bone healing after rotator cuff (RC) repair is still the formation of granulation tissue at the tendon-bone interface rather than the formation of fibrocartilage, which is the crucial structure in native tendon insertion and can be observed after knee ligament reconstruction. The interposition of calcium phosphate materials has been found to be able to enhance tendon-bone healing in knee ligament reconstruction. However, whether the interposition of these kinds of materials can enhance tendon-bone healing or even change the current nature of tendon-bone healing after RC repair still needs to be explored.

HYPOTHESIS

The interposition of calcium phosphate materials during RC repair would enhance tendon-bone healing or change its current nature of granulation tissue formation into a more favorable process.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 144 male Sprague-Dawley rats underwent unilateral detachment of the supraspinatus tendon, followed by delayed repair after 3 weeks. The animals were allocated into 1 of 3 groups: (1) repair alone, (2) repair with Ca5(PO4)2SiO4 (CPS) bioceramic interposition, or (3) repair with hydroxyapatite (HA) bioceramic interposition at the tendon-bone interface. Animals were sacrificed at 2, 4, or 8 weeks postoperatively, and microcomputed tomography (micro-CT) was used to quantify the new bone formation at the repair site. New fibrocartilage formation and collagen organization at the tendon-bone interface was evaluated by histomorphometric analysis. Biomechanical testing of the supraspinatus tendon-bone complex was performed. Statistical analysis was performed using 1-way analysis of variance. Significance was set at P < .05.

RESULTS

The micro-CT analysis demonstrated remarkable osteogenic activity and osteoconductivity to promote new bone formation and ingrowth of CPS and HA bioceramic, with CPS bioceramic showing better results than HA. Histological observations indicated that CPS bioceramic had excellent biocompatibility and biodegradability. At early time points after the RC repair, CPS bioceramic significantly increased the area of fibrocartilage at the tendon-bone interface compared with the control and HA groups. Moreover, CPS and HA bioceramics had significantly improved collagen organization. Biomechanical tests indicated that the CPS and HA groups have greater ultimate load to failure and stiffness than the control group at 4 and 8 weeks, and the CPS specimens exhibited the maximum ultimate load to failure, stiffness, and stress of the healing enthesis.

CONCLUSION

Both CPS and HA bioceramics aid in cell attachment and proliferation and accelerate new bone formation, and CPS bioceramic has a more prominent effect on tendon-to-bone healing.

CLINICAL RELEVANCE

Local application of CPS and HA bioceramic at the tendon-bone interface shows promise in improving healing after rotator cuff tear repair.

Biological augmentation of rotator cuff repair using bFGF-loaded electrospun poly(lactide-co-glycolide) fibrous membranes

Clinically, rotator cuff tear (RCT) is among the most common shoulder pathologies. Despite significant advances in surgical techniques, the re-tear rate after rotator cuff (RC) repair remains high. Insufficient healing capacity is likely the main factor for reconstruction failure. This study reports on a basic fibroblast growth factor (bFGF)-loaded electrospun poly(lactide-co-glycolide) (PLGA) fibrous membrane for repairing RCT. Implantable biodegradable bFGF-PLGA fibrous membranes were successfully fabricated using emulsion electrospinning technology and then characterized and evaluated with in vitro and in vivo cell proliferation assays and repairs of rat chronic RCTs. Emulsion electrospinning fabricated ultrafine fibers with a core-sheath structure which secured the bioactivity of bFGF in a sustained manner for 3 weeks. Histological observations showed that electrospun fibrous membranes have excellent biocompatibility and biodegradability. At 2, 4, and 8 weeks after in vivo RCT repair surgery, electrospun fibrous membranes significantly increased the area of glycosaminoglycan staining at the tendon-bone interface compared with the control group, and bFGF-PLGA significantly improved collagen organization, as measured by birefringence under polarized light at the healing enthesis compared with the control and PLGA groups. Biomechanical testing showed that the electrospun fibrous membrane groups had a greater ultimate load-to-failure and stiffness than the control group at 4 and 8 weeks. The bFGF-PLGA membranes had the highest ultimate load-to-failure, stiffness, and stress of the healing enthesis, and their superiority compared to PLGA alone was significant. These results demonstrated that electrospun fibrous membranes aid in cell attachment and proliferation, as well as accelerating tendon-bone remodeling, and bFGF-loaded PLGA fibrous membranes have a more pronounced effect on tendon-bone healing. Therefore, augmentation using bFGF-PLGA electrospun fibrous membranes is a promising treatment for RCT.

Gap formation in a transosseous rotator cuff repair as a function of bone quality

BACKGROUND

The transosseous approach has been well known for a long time as a valid repair approach. Over time, various criticisms have been raised over this technique principally classifiable in two main categories: technical difficulty and related reproducibility in an arthroscopic environment, and repair stability (in the suture-bone contact area). About cyclic performance, several authors have conceived test setups with the aim of simulating a real environment in dynamic load conditions. The aim of this study was to monitor gap formation in a cyclic test setup.

METHODS

The performance (measured as gap formation) has been monitored as a function of bone density to verify the effect of the latter. The test blocks have been shaped using sawbones® test bricks (Malmo, Sweden) of different densities, and the following values have been tested: 10, 15, 20, 30 and 40pcf.

FINDINGS

The comparison has been made between the two groups: traditional transosseous and new approach with an interposed device. Regarding the traditional transosseous approach in a 10-pcf environment, not even the first loading cycle was completed, the whole bone bridge was destroyed in the first loading ramp and no further loading capability was present in the repair. By increasing the block density, the surface damage in the suture-block contact decreased.

INTERPRETATION

With this work, it has been demonstrated how the traditional transosseous approach is strongly influenced by the bone quality up to the point where, in certain conditions, a safe and reliable repair is not guaranteed.

Tensile properties of a morphologically split supraspinatus tendon

The supraspinatus tendon consists morphologically of two sub-regions, anterior and posterior. The anterior sub-region is thick and tubular while the posterior is thin and strap-like. The purpose of this study was to compare the structural and mechanical properties of the anterior and posterior sub-regions of the supraspinatus tendon. The supraspinatus tendons from seven human cadaveric shoulders were morphologically divided into the anterior and posterior sub-regions. Length, width, and thickness were measured. A servo-hydraulic testing machine (MTS Systems Corporation, Minneapolis, MN) was used for tensile testing. The maximal load at failure, modulus of elasticity and ultimate tendon stress were calculated. Repeated measures were used for statistical comparisons. The mean anterior tendon cross-sectional area was 47.3 mm(2) and the posterior was 32.1 mm(2) . Failure occurred most often at the insertion site: anterior (5/7) and posterior (6/7). All parameters of the anterior sub-region were significantly greater than those of the posterior sub-region. The moduli of elasticity at the insertion site were 592.4 MPa in the anterior sub-region and 217.7 MPa in the posterior (P = 0.01). The ultimate failure loads were 779.2 N in the anterior sub-region and 335.6 N in the posterior (P = 0.003). The ultimate stresses were 22.1 MPa in the anterior sub-region and 11.6 MPa in the posterior (P = 0.008). We recognized that the anterior and posterior sub-regions of the SSP tendon have significantly different mechanical properties. In a future study, we need to evaluate how best to repair an SSP tendon considering these region-specific properties.

The rotator cuff tear repair with a new arthroscopic transosseous system: the Sharc-FT(®)

PURPOSE

Today, in rotator cuff tear repair, the transosseous sutures are considered superior from a biological and biomechanical point of view. Our purpose is to present the early clinical and biomechanical data of a new arthroscopic rotator cuff tear transosseous repair system: the Sharc-FT®.

MATERIALS AND METHODS

A total of 34 patients with rotator cuff tear affecting supraspinatus and infraspinatus, 1 to 3 cm wide, were treated and evaluated from 2010 to 2013. The average age was 63.2 years. Mean follow-up was 18.6 months. All patients were assessed through Constant score in the preoperative step and at 3-, 6-, and 12-month follow-up, performing an MRI 6 months after surgery.

RESULTS

The patients have shown a mean preoperative Constant score of 24.5 pt that constantly increases after surgery, until a mean value of 86.9 at 12 months. Regarding complications two cases of adhesive capsulitis were recorded.

CONCLUSIONS

This device permits to obtain transosseous sutures with cortical fixation; to greatly reduce the problems of lack of bone resistance; to decrease motion at tendon-footprint interface improving fatigue resistance; to make the stress-load distribution homogeneous at the footprint, thus optimizing biological healing. A later evaluation will be necessary, especially for the incidence of retears.

Initial fixation strength of transosseous-equivalent suture bridge rotator cuff repair is comparable with transosseous repair

BACKGROUND

The outcome of rotator cuff repair correlates with tendon healing. Early studies of arthroscopic rotator cuff repair demonstrate lower healing rates than traditional open techniques. Transosseous-equivalent repair techniques (suture bridge) were developed to improve the initial fixation strength.

PURPOSE

To compare the initial in vitro tensile fixation strength of a transosseous-equivalent suture bridge (TOE-SB) rotator cuff repair construct to a traditional transosseous (TO) suture construct.

STUDY DESIGN

Controlled laboratory study.

METHODS

Identical simulated rotator cuff tears were created on 8 matched pairs of humeri. Each matched pair underwent repair with 4 sutures using either the TOE-SB or TO technique. Initial fixation strength was tested in a custom testing jig. Each shoulder underwent 1000 cycles each of low and then high load testing. Gap displacement was measured at anterior and posterior sites of the repair with digital video tracking of paired reflective markers and recorded at predetermined cycle intervals.

RESULTS

There were no statistically significant differences in gap formation at the repair sites under low or high load conditions between TOE-SB and TO techniques. The mean maximal gap formation of the repairs during low load testing in the TOE-SB and TO constructs was 0.93 ± 0.88 mm and 0.55 ± 0.22 mm, respectively (P = .505). The mean maximal gap formation during high load testing in the TOE-SB and TO constructs was 2.04 ± 1.10 mm and 2.28 ± 1.62 mm, respectively (P = .517). The most significant increase in gap distance occurred at the transition from low load to high load in both constructs. Most of the incremental displacement occurred within the first 100 cycles for both high and low load testing (P < .001).

CONCLUSION

The arthroscopic TOE-SB technique is comparable in initial fixation strength to the traditional TO simple suture repair technique.

CLINICAL RELEVANCE

Arthroscopic techniques can achieve initial fixation strength comparable with traditional TO techniques performed without suture anchors.

Synthetic augmentation for massive rotator cuff tears

The management of massive, irreparable rotator cuff tears is challenging. They are associated with persistent defects, weakness, and poor outcomes, and can cause an uncoupling of forces across the glenohumeral joint, with unstable shoulder kinematics. There has been much interest in the development of scaffolds to bridge massive rotator cuff tears. As allograft materials may produce inflammatory responses in the host, there is notable interest in developing synthetic grafts for surgical use. Benefits and limitations of the available synthetic scaffolds for augmentation of rotator cuff tears are reported in the present review.

Suture loosening and its effect on tendon fixation in knotless double-row rotator cuff repairs

PURPOSE

We have occasionally observed suture loosening in initial suture legs after final fixation of adjacent suture legs in the lateral row of rotator cuff repairs during arthroscopic rotator cuff repair with transosseous-equivalent suture-bridge constructs. We sought to determine how this occurred and what effects it had on tendon fixation stability.

METHODS

Six pairs of fresh-frozen human shoulders were prepared with a simulated cuff defect. A suture-bridge repair was performed in each specimen with one of each pair randomized to one type of "knotless" lateral-row screw-in anchor and the other of the pair to a knotless push-in type. The repairs were cyclically loaded with 100 N for 1,000 cycles. Suture leg tensions were measured during the repair and after cycling. Lateral tendon laxity was measured before and after cycling. A pilot study on the effect of suture tension on the tendon contact footprint was also performed.

RESULTS

The initial suture legs did not show a decrease in tension after the second lateral-row anchor was secured. Tension of the suture legs after cycling showed that no one leg loosened more than another; however, they all loosened when compared with total suture tensions before cycling (0.1 to 1.0 mm, P = .008). There was no significant difference between suture tension changes for the 2 anchor types after cycling (P = .140). Although the lateral tendon laxity increased slightly (0.04 mm) after cycling, this was not significant (P = .245), nor was there a difference between anchor types.

CONCLUSIONS

Suture loosening occurred after cycling these rotator cuff repairs, but this did not appear to affect lateral tendon laxity for the 2 lateral anchor types studied, although medial tendon movement was observed.

CLINICAL RELEVANCE

Suture loosening after cycling the 2 transosseous-equivalent suture-bridge repairs studied could affect the area and pressure of tendon-bone contact.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Total cost and operating room time comparison of rotator cuff repair techniques at low, intermediate, and high volume centers: mini-open versus all-arthroscopic

BACKGROUND

The objective of this study was to determine mean cost and operative time differences between mini-open and all-arthroscopic rotator cuff repair techniques at surgical centers of low, intermediate, and high annual rotator cuff repair volume.

METHODS

The 2006 New York State Ambulatory Surgery Database (NY-SASD) was utilized. It represents 100% of all outpatient procedures performed in hospital-affiliated and freestanding surgical centers, containing 10,658,923 patients for 2006 alone. Only patients who had an arthroscopic acromioplasty and either open or arthroscopic rotator cuff repair were included, leaving 5,224 patients for the study. These were divided into 2 groups: the mini-open group (1,334) and the all-arthroscopic group (3,890). Surgical center volume data were divided into 3 groups: low volume (<75 rotator cuff repairs per year), intermediate volume (75-199 rotator cuff repairs per year), and high volume (200+ rotator cuff repairs per year).

RESULTS

Patient age and gender were normally distributed within the 2 groups with no significant differences between them (P = .82 and P = .31, respectively). Operative time was significantly shorter in the mini-open group (103 minutes) compared to the all-arthroscopic group (113 minutes), P < .00001. Surgical charges were also significantly less in the mini-open group ($7,841) compared to the all-arthroscopic group ($8,985), P < .00001. Regardless of the repair method, high volume surgical centers were significantly more expensive when compared to low and intermediate volume centers, P < .00001.

CONCLUSION

The mini-open rotator cuff repair technique requires significantly less operative time and is significantly less expensive than the all-arthroscopic repair. Regardless of the repair technique, high volume surgical centers cost significantly more than low and intermediate volume surgical centers.

Biomechanical analysis of an ovine rotator cuff repair via porous patch augmentation in a chronic rupture model

BACKGROUND

Rotator cuff repair is a commonly performed procedure, but many of these repairs fail in the postoperative term. Despite advances in surgical methods to optimize the repair, failure rates still persist clinically, thereby suggesting the need for novel mechanical or biological augmentation strategies. Nonresorbable implants provide an appealing approach because patch materials may confer acute mechanical stability and act as a conductive scaffold for tissue ingrowth at the site of the tendon insertion.

HYPOTHESIS

The polyurethane scaffold mesh will confer greater biomechanical function relative to a nonaugmented repair after 12 weeks in vivo using a chronic ovine model of rotator cuff repair.

STUDY DESIGN

Controlled laboratory study.

METHODS

After development of the chronic rupture model, the tensile failure properties of the nonresorbable mesh-augmented repair (n, 9) were compared with those of a surgical control in an ovine model (n, 8).

RESULTS

Rotator cuff repair with the scaffold mesh in the chronic model resulted in a significant 74.2% increase in force at failure relative to the nonaugmented surgical control (P = .021). Apparent increases in stiffness (55.4%) and global displacement at failure (21.4%) in the mesh-augmented group relative to nonaugmented controls were not significant (P = .126 and P = .123, respectively). At the study endpoint, the augmented shoulders recovered 37.8% and 40.7% of the force at failure and stiffness, respectively, of intact, nonoperated controls.

CONCLUSION

Using the previously described chronic rupture model, this study demonstrated that repair of a chronic tendon tear with the polyurethane scaffold mesh provides greater mechanical strength in the critical healing period than that of traditional suture anchor repair.

CLINICAL RELEVANCE

This device could be used to enhance the surgical repair of the rotator cuff and consequently improve long-term clinical outcome.