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

Load to Failure and Stiffness: Anchor Placement and Suture Pattern Effects on Load to Failure in Rotator Cuff Repairs

BACKGROUND

Rotator cuff tendinopathy is a frequent cause of shoulder pain that can lead to decreased strength and range of motion. Failures after using the single-row technique of rotator cuff repair have led to the development of the double-row technique, which is said to allow for more anatomical restoration of the footprint.

PURPOSE

To compare 5 different types of suture patterns while maintaining equality in number of anchors. The hypothesis was that the Mason-Allen-crossed cruciform transosseous-equivalent technique is superior to other suture configurations while maintaining equality in suture limbs and anchors.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 25 fresh-frozen cadaveric shoulders were randomized into 5 suture configuration groups: single-row repair with simple stitch technique; single-row repair with modified Mason-Allen technique; double-row Mason-Allen technique; double-row cross-bridge technique; and double-row suture bridge technique. Load and displacement were recorded at 100 Hz until failure. Stiffness and bone mineral density were also measured.

RESULTS

There was no significant difference in peak load at failure, stiffness, maximum displacement at failure, or mean bone mineral density among the 5 suture configuration groups (P < .05).

CONCLUSION

According to study results, when choosing a repair technique, other factors such as number of sutures in the repair should be considered to judge the strength of the repair.

CLINICAL RELEVANCE

Previous in vitro studies have shown the double-row rotator cuff repair to be superior to the single-row repair; however, clinical research does not necessarily support this. This study found no difference when comparing 5 different repair methods, supporting research that suggests the number of sutures and not the pattern can affect biomechanical properties.

Assessment and treatment strategies for rotator cuff tears

Tears of the rotator cuff are common and becoming an increasingly frequent problem. There is a vast amount of literature on the merits and limitations of the various methods of clinical and radiological assessment of rotator cuff tears. This is also the case with regard to treatment strategies. Certain popular beliefs and principles practiced widely and the basis upon which they are derived may be prone to inaccuracy. We provide an overview of the historical management of rotator cuff tears, as well as an explanation for how and why rotator cuff tears should be managed, and propose a structured methodology for their assessment and treatment.

Factors affecting healing after arthroscopic rotator cuff repair

Rotator cuff repair has been shown to have good long-term results. Unfortunately, a significant proportion of repairs still fail to heal. Many factors, both patient and surgeon related, can influence healing after repair. Older age, larger tear size, worse muscle quality, greater muscle-tendon unit retraction, smoking, osteoporosis, diabetes and hypercholesterolemia have all shown to negatively influence tendon healing. Surgeon related factors that can influence healing include repair construct-single vs double row, rehabilitation, and biologics including platelet rich plasma and mesenchymal stem cells. Double-row repairs are biomechanically stronger and have better healing rates compared with single-row repairs although clinical outcomes are equivalent between both constructs. Slower, less aggressive rehabilitation programs have demonstrated improved healing with no negative effect on final range of motion and are therefore recommended after repair of most full thickness tears. Additionally no definitive evidence supports the use of platelet rich plasma or mesenchymal stem cells regarding improvement of healing rates and clinical outcomes. Further research is needed to identify effective biologically directed augmentations that will improve healing rates and clinical outcomes after rotator cuff repair.

A cost analysis of single-row versus double-row and suture bridge rotator cuff repair methods

PURPOSE

To calculate the costs to the US healthcare system of transition from single-row (SR) to double-row (DR) rotator cuff repair (RCR) and to calculate the decrease in re-operations for re-tear that DR RCR would need to accomplish in order to render the transition cost-neutral.

METHODS

Standard accounting methods were used to determine the cost of a single RCR, the annual cost to the US healthcare system of rotator cuff surgery, the cost of a single-revision RCR, and the decrease in revision for re-tear rate necessary to make DR or suture bridge (SB) methods cost-neutral in comparison with SR methods. We varied tear size, operating room cost, time required for implant placement, annual tear size distribution, and repair method.

RESULTS

The cost of RCR ranged from $7,572 (SR, <1 cm tear) to $12,979 (DR, >5 cm tear). Complete conversion from SR RCR to a DR technique without an associated decrease in revision surgeries would increase the annual US healthcare cost between $80 million and $262 million per year. To obtain cost neutrality, use of DR or SB methods would need to result in one fewer revision in every 17 primary repairs (for tears <1 cm) to one fewer in every four primary repairs (for tears >5 cm).

CONCLUSIONS

Conversion from SR to DR or SB RCR techniques would result in considerable increases in healthcare expenditures. Since the large decreases in revision surgery rates necessary to justify DR or SB repairs purely on a cost basis may not be realistic or even possible, the use of these methods should be supported by evidence of improved structural healing rates and quality-adjusted life years in comparison with SR methods.

LEVEL OF EVIDENCE

IV.

Biomechanical evaluation of suture-tendon interface and tissue holding of three suture configurations in torn and degenerated versus intact human rotator cuffs

PURPOSE

The purpose of this study was to biomechanically evaluate suture-tendon interface and tissue holding of three sutures in torn and degenerated versus intact human rotator cuffs.

METHODS

Sixty-three human rotator cuff tendons were divided into torn degenerated group (TDG), n = 21 and intact group (IG), n = 42. Ultimate tension load (UTL) and cyclic loading were tested for three arthroscopic sutures: simple, horizontal, and massive cuff sutures (MCS).

RESULTS

Ultimate tension load was significantly higher (p < 0.05) for the MCS (194 ± 68 N) in comparison with the simple (105 ± 48 N) and horizontal sutures (141 ± 49 N) in IG. In TDG, UTL was not significantly higher (n.s.) for MCS (118 ± 49 N), simple (79 ± 30 N), and horizontal sutures (107 ± 28 N) in comparison with IG. MCS (118 ± 49 N) showed no significantly superior UTL in comparison with the simple and horizontal sutures in the TDG. MCA elongation was 0.6 ± 0.7 mm in the IG and 1.3 ± 0.7 mm in the TDG, while horizontal suture elongation was 0.7 ± 0.4 mm in the IG and 1.3 ± 0.5 mm in the TDG. Simple suture elongation was 1.1 ± 0.5 mm in the IG and 1.6 ± 0.7 mm in the TDG.

CONCLUSION

Human torn and degenerated rotator cuffs have poor tissue quality, significantly lower UTL and higher cyclic elongation in comparison with intact cuffs regardless of the type of suture used for repair, which invites the need for repair techniques that grasps greater tissue volume in addition to augmentation techniques.

CLINICAL RELEVANCE

Clinicians better use repair techniques that grasp greater tissue volume (e.g. MCS, modified Mason-Allen cross bridge, double-row cross bridge, etc.) when repairing the torn and degenerated rotator cuffs.

In vivo blood flow after rotator cuff reconstruction in a sheep model: comparison of single versus double row

PURPOSE

Arthroscopic double-row (DR) suture anchor repair of rotator cuff tears has been shown to be superior to most single-row (SR) techniques with regard to footprint reconstruction, load to failure and tendon-to-bone contact pressures. The hypothesis of this study was that the greater contact pressures of DR techniques would compromise blood flow to a higher degree than SR repair. The aim of this experimental study was to evaluate the effect of a DR and a SR technique on tendon blood flow in a sheep model.

METHODS

Eighteen sheep underwent detachment and immediate repair of the infraspinatus tendon using either a Mason-Allen or a suture-bridge technique. Tendon blood flow was measured using laser Doppler flowmetry before detachment, immediately after repair and 12 weeks thereafter. Six regions of interest were measured, three over the lateral and three over the medial aspect of the footprint.

RESULTS

Immediately after repair, tendon blood flow decreased significantly in both repair groups (P = 0.004). In the SR group, blood flow decreased by 100.1 arbitrary units (AU) (83.6 %) after repair, in the DR by 81.4 AU (90.5 %). Subgroup analysis showed blood flow over the lateral aspect of the footprint decreased by 126.3 AU (92.2 %) in the SR and 84.4 AU (90.9 %) in the DR group, whereas over the medial aspect, it decreased by 73.9 AU (72.0 %) in the SR and 78.5 AU (90.1 %) in the DR group. None of the differences between the groups were significant. At 12 weeks, measured blood flow in the DR group had increased to 90.1 AU (100.2 %) compared to the native tendons and was at 72.5 AU (60.5 %) for the SR group. Again, the difference between SR and DR group was not statistically significant (n.s.). Assessment for retears showed that 4 of 8 tendons (50 %) in the DR group and 3 of 9 tendons (33.3 %) in the SR group had to be classified as re-ruptures.

CONCLUSION

Suture anchor repair leads to an intraoperative decrease in tendon blood flow regardless of the repair technique. A significant difference between SR and DR repair was not found. These findings indicate that tendon blood flow should not be a factor to determine the use of either repair technique over the other.

Viscoelastic properties of common suture material used for rotator cuff repair and arthroscopic procedures

PURPOSE

The purpose of this study was to evaluate the viscoelastic properties of 5 suture materials, commonly used in arthroscopic rotator cuff repairs, when subjected to physiological loads.

METHODS

We evaluated 5 commercially available No. 2 sutures undergoing both creep and cyclic testing in both dry air and phosphate-buffered saline solution (PBS) maintained at 37°C. The selected sutures were MagnumWire (ArthroCare, Austin, TX), Ethibond (Ethicon, Somerville, NJ), FiberWire (Arthrex, Naples, FL), Orthocord (DePuy, Warsaw, IN), and Force Fiber (Tornier, Bloomington, MN).

RESULTS

Regarding creep testing, in the PBS test environment, FiberWire showed the greatest stiffness (71.1 ± 2.1 N/mm), the smallest initial extension at the 60-N load (1.10 ± 0.04 mm), and the smallest amount of creep (0.57 ± 0.01 mm). Orthocord showed the smallest amount of relaxed elongation in PBS (0.73 ± 0.11 mm). Regarding cyclic testing, in the PBS testing environment, Ethibond exhibited the smallest dynamic creep (0.28 ± 0.02 mm), FiberWire displayed the smallest peak-to-peak displacement (0.17 ± 0.00 mm), and Orthocord showed the smallest amount of relaxed elongation after cyclic loading (0.63 ± 0.11 mm).

CONCLUSIONS

FiberWire consistently displayed more extreme viscoelastic properties--greater stiffness and less extensibility--than the other suture types studied. Orthocord showed the smallest amount of relaxed elongation in both testing environments. Differences in testing environment affect the behavior of each suture type. Testing in physiologically approximating conditions such as PBS maintained at 37°C is warranted.

CLINICAL RELEVANCE

Although many other factors affect the success of rotator cuff repairs, the viscoelastic properties of sutures may be a useful predictor of suture performance.

Incidence of retear with double-row versus single-row rotator cuff repair

Rotator cuff tears have a high recurrence rate, even after arthroscopic rotator cuff repair. Although some biomechanical evidence suggests the superiority of the double-row vs the single-row technique, clinical findings regarding these methods have been controversial. The purpose of this study was to determine whether the double-row repair method results in a lower incidence of recurrent tearing compared with the single-row method. Electronic databases were systematically searched to identify reports of randomized, controlled trials (RCTs) comparing single-row with double-row rotator cuff repair. The primary outcome assessed was retear of the repaired cuff. Secondary outcome measures were the American Shoulder and Elbow Surgeons (ASES) shoulder score, the Constant shoulder score, and the University of California, Los Angeles (UCLA) score. Heterogeneity between the included studies was assessed. Six studies involving 428 patients were included in the review. Compared with single-row repair, double-row repair demonstrated a lower retear incidence (risk ratio [RR]=1.71 [95% confidence interval (CI), 1.18-2.49]; P=.005; I(2)=0%) and a reduced incidence of partial-thickness retears (RR=2.16 [95% CI, 1.26-3.71]; P=.005; I(2)=26%). Functional ASES, Constant, and UCLA scores showed no difference between single- and double-row cuff repairs. Use of the double-row technique decreased the incidence of retears, especially partial-thickness retears, compared with the single-row technique. The functional outcome was not significantly different between the 2 techniques. To improve the structural outcome of the repaired rotator cuff, surgeons should use the double-row technique. However, further long-term RCTs on this topic are needed.

Biomechanical analysis of rotator cuff repairs with extracellular matrix graft augmentation

Despite advances in surgical techniques, 20% to 90% of rotator cuff (RTC) repairs fail. They tend to fail at the suture-tendon junction due to tension at the repair and gap formation prior to healing. This study evaluated the gap formation and ultimate tensile failure loads of a RTC repair with a decellularized human dermal allograft. Augmentation of a RTC repair with an extracellular matrix graft decreased gap formation and increased load to failure in a human RTC repair model.

The evaluation and treatment of rotator cuff pathology

Rotator cuff pathology accounts for most presentations of shoulder pain to primary care clinics. History and physical examination are important for excluding other causes of shoulder pain, while imaging assists in confirming the diagnosis and defining the severity of the abnormality. Treatment options include nonsteroidal anti-inflammatory agents, subacromial corticosteroid injections, and exercise therapy. Surgical intervention is generally reserved for those failing nonoperative measures and/or healthy, young, and middle-aged adults with full-thickness rotator cuff tears. No surgical technique has proved to be superior. Despite surgery, about 20% of patients experience retears, more likely occurring in those with larger tears.

Surface-holding repair: an original arthroscopic rotator cuff repair technique

BACKGROUND

Arthroscopic rotator cuff repair provides satisfactory results; however, there is still a high rate of re-tear. The objective of this study was to present a surface-holding technique that we recently developed for arthroscopic rotator cuff repair in detail and to evaluate the clinical outcome as well as cuff repair integrity with this new method.

MATERIALS AND METHODS

A consecutive series of 116 patients with full-thickness rotator cuff tears underwent arthroscopic surface-holding repair and were monitored with the Japanese Orthopaedic Association, Constant-Murley, and University of California-Los Angeles scores to assess the clinical outcome. The mean follow-up period was 17.9 months (range, 12-40 months). Cuff repair integrity was evaluated by magnetic resonance imaging.

RESULTS

All 3 rating systems at the time of final follow-up reflected a significant improvement in functional recovery of the shoulder compared with the preoperative scores. The overall rate of rotator cuff retear was 19.0% (22 of 116 shoulders), and the rates were 13.6% (9 of 66 shoulders) for small and medium-sized tears and 26% (13 of 50 shoulders) for large and massive tears. The rate for large and massive tears was much higher in patients older than 70 years (58.3%) compared with those younger than 70 years (36.3%), whereas the retear rates were similar in these 2 groups (22.2% and 17.5%, respectively).

CONCLUSIONS

Arthroscopic surface-holding repair technique with medial suture and transosseous fixation improved rotator cuff healing. This method may be useful both for young patients and for elderly patients, who frequently have chronic large and massive tears, including osteoporotic bones.

Clinical and structural outcomes after arthroscopic single-row versus double-row rotator cuff repair: a systematic review and meta-analysis of level I randomized clinical trials

BACKGROUND

The purpose of this study was to perform a systematic review and meta-analysis of all available level I randomized controlled trials comparing single-row with double-row repair to statistically compare clinical outcomes and imaging-diagnosed re-tear rates.

METHODS

A literature search was undertaken to identify all level I randomized controlled trials comparing structural or clinical outcomes after single-row versus double-row rotator cuff repair. Clinical outcomes measures included in the meta-analysis were the American Shoulder and Elbow Surgeons, University of California-Los Angeles, and Constant scores; structural outcomes included imaging-confirmed re-tears. Meta-analyses compared raw mean differences in outcomes measures and relative risk ratios for imaging-diagnosed re-tears after single-row or double-row repairs by a random-effects model.

RESULTS

The literature search identified a total of 7 studies that were included in the meta-analysis. There were no significant differences in preoperative to postoperative change in American Shoulder and Elbow Surgeons, University of California-Los Angeles, or Constant scores between the single-row and double-row groups (P = .440, .116, and .156, respectively). The overall re-tear rate was 25.9% (68/263) in the single-row group and 14.2% (37/261) in the double-row group. There was a statistically significant increased risk of sustaining an imaging-proven re-tear of any type in the single-row group (relative risk, 1.76 [95% confidence interval, 1.25-2.48]; P = .001), with partial-thickness re-tears accounting for the majority of this difference (relative risk, 1.99 [95% confidence interval, 1.40-3.82]; P = .039).

CONCLUSION

Single-row repairs resulted in significantly higher re-tear rates compared with double-row repairs, especially with regard to partial-thickness re-tears. However, there were no detectable differences in improvement in outcomes scores between single-row and double-row repairs.

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.

Comparisons of retear patterns for 3 arthroscopic rotator cuff repair methods

BACKGROUND

Only a few studies have reported an unusual retear pattern after arthroscopic rotator cuff repair based on the repair method.

PURPOSE

To compare the retear pattern of the arthroscopic single-row technique (SRT), conventional suture-bridge technique (SBT), and knotless suture-bridge technique (K-SBT) for rotator cuff tears.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study evaluated 65 shoulders with retears revealed on magnetic resonance imaging at least 6 months after arthroscopic repair for a full-thickness rotator cuff tear. A retear was revealed in 21, 22, and 22 shoulders after the SRT, SBT, and K-SBT, respectively. Retears were classified as type 1 (unhealed tendons), type 2 (medially ruptured tendons with a healed footprint), or type 3 (unable to classify). Retear patterns were classified as full- or partial-thickness lesions; partial-thickness retears were further classified as articular- or bursal-side lesions.

RESULTS

A type 1 retear was observed in 71.4%, 40.9%, and 54.5% and a type 2 retear in 23.8%, 59.0%, and 40.9% of patients in the SRT, SBT, and K-SBT groups, respectively. No significant differences were observed among the 3 groups together (P = .195); however, a significant difference was observed between the SRT and SBT groups alone (P = .049). No significant differences were observed for either type 1 (P = .121) or type 2 (including both full- and partial-thickness) retears (P = .064) among the 3 groups together. When respective pairs of groups were compared, a significant difference was noted in both type 1 (P = .044) and type 2 retears (P = .019) between the SRT and SBT groups alone. No significant differences were observed in type 1 (P = .281) or type 2 full-thickness retears (P = .117) among the 3 groups together. When pairs of groups were compared, a significant difference in type 2 full-thickness retears was detected between the SRT and SBT groups alone (P = .037).

CONCLUSION

The SBT has a different retear pattern than that of the SRT. However, the K-SBT retear pattern was not different from that of the SRT.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Ultrasound evaluation of arthroscopic full-thickness supraspinatus rotator cuff repair: single-row versus double-row suture bridge (transosseous equivalent) fixation. Results of a prospective, randomized study

BACKGROUND

The purpose of this study was to compare the structural outcomes of a single-row rotator cuff repair and double-row suture bridge fixation after arthroscopic repair of a full-thickness supraspinatus rotator cuff tear.

MATERIAL AND METHODS

We evaluated with diagnostic ultrasound a consecutive series of ninety shoulders in ninety patients with full-thickness supraspinatus tears at an average of 10 months (range, 6-12) after operation. A single surgeon at a single hospital performed the repairs. Inclusion criteria were full-thickness supraspinatus tears less than 25 mm in their anterior to posterior dimension. Exclusion criteria were prior operations on the shoulder, partial thickness tears, subscapularis tears, infraspinatus tears, combined supraspinatus and infraspinatus repairs and irreparable supraspinatus tears. Forty-three shoulders were repaired with single-row technique and 47 shoulders with double-row suture bridge technique. Postoperative rehabilitation was identical for both groups. Ultrasound criteria for healed repair included visualization of a tendon with normal thickness and length, and a negative compression test.

RESULTS

Eighty-three patients were available for ultrasound examination (40 single-row and 43 suture-bridge). Thirty of 40 patients (75%) with single-row repair demonstrated a healed rotator cuff repair compared to 40/43 (93%) patients with suture-bridge repair (P = .024).

CONCLUSION

Arthroscopic double-row suture bridge repair (transosseous equivalent) of an isolated supraspinatus rotator cuff tear resulted in a significantly higher tendon healing rate (as determined by ultrasound examination) when compared to arthroscopic single-row repair.

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

Purpose:

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

Materials and Methods:

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

Results:

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

Conclusions:

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

Clinical Relevance:

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

Outcomes of single-row versus double-row arthroscopic rotator cuff repair: a systematic review and meta-analysis of current evidence

PURPOSE

Our purpose was to perform a systematic review and meta-analysis of the clinical outcomes of single-row versus double-row repair.

METHODS

An electronic search was performed using PubMed, EMBASE, and the Cochrane Library up to September 30, 2012. Studies that met the inclusion and exclusion criteria were assessed for quality of methodology. The primary analysis included Level I evidence from studies examining single-row versus double-row repair. The second meta-analysis and subgroup analysis were performed for evidence Levels I, II, and III.

RESULTS

The primary analysis of studies providing 6 Level I randomized controlled trials showed no clinically significant differences in Constant scores, University of California, Los Angeles (UCLA), and American Shoulder and Elbow Surgeons (ASES) scores between double-row and single-row rotator cuff repair. The overall odds ratio (OR) of intact rotator cuff tendon healing was 1.93 in patients treated with double-row versus single-row repair, and the difference was significant. The results of the second meta-analysis including evidence Levels I, II, and III were similar to those of the primary analysis. In the subgroup with tears less than 3 cm, there was no statistically significant difference between the groups with regard to shoulder functional score and structure integrity. A statistically significant benefit of double-row repair in the ASES and UCLA scores was observed in the subgroup with tears greater than 3 cm; however, these differences were not clinically significant. The OR for tendon healing was found to be more favorable for double-row repair than for single-row repair in the subgroup with tears greater than 3 cm.

CONCLUSIONS

Double-row repair provides a significantly higher rate of intact tendon healing than does single-row repair, and this advantage was mainly reflected in patients with large or massive tears. However, this benefit did not translate into clinically confirmed functional improvement. Thus, the double-row technique should be used only in carefully selected patients.

LEVEL OF EVIDENCE

Level III, systematic review of Levels I, II, and III studies.

Single-row or double-row fixation technique for full-thickness rotator cuff tears: a meta-analysis

Background

The single-row and double-row fixation techniques have been widely used for rotator cuff tears. However, whether the double-row technique produces superior clinical or anatomic outcomes is still considered controversial. This study aims to use meta-analysis to compare the clinical and anatomical outcomes between the two techniques.

Methods

The Pubmed, Embase, and Cochrane library databases were searched for relevant studies published before November 1, 2012. Studies clearly reporting a comparison of the single-row and double-row techniques were selected. The Constant, ASES, and UCLA scale systems and the rotator cuff integrity rate were evaluated. The weighted mean differences and relative risks were calculated using a fixed-effects or random-effects model.

Results

Eight studies were included in this meta-analysis. The weighted mean differences of the ASES (−0.84; P = 0.04; I² = 0%) and UCLA (−0.75; P = 0.007; I² = 0%) scales were significantly low in the single-row group for full-thickness rotator cuff tears. For tear sizes smaller than 3 cm, no significant difference was found between the groups no matter in Constant (P = 0.95; I² = 0%), ASES (P = 0.77; I² = 0%), or UCLA (P = 0.24; I² = 13%) scales. For tear sizes larger than 3 cm, the ASES (−1.95; P = 0.001; I² = 49%) and UCLA (−1.17; P = 0.006; I² = 0%) scales were markedly lower in the single-row group. The integrity of the rotator cuff (0.81; P = 0.0004; I² = 10%) was greater and the partial thickness retear rate (1.93; P = 0.007; I² = 10%) was less in the double-row group. Full-thickness retears showed no difference between the groups (P = 0.15; I² = 0%).

Conclusion

The meta-analysis suggests that the double-row fixation technique increases post-operative rotator cuff integrity and improves the clinical outcomes, especially for full-thickness rotator cuff tears larger than 3 cm. For tear sizes smaller than 3 cm, there was no difference in the clinical outcomes between the two techniques.

Level of Evidence

Level I.

Current biomechanical concepts for rotator cuff 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.

Outcome and structural integrity of rotator cuff after arthroscopic treatment of large and massive tears with double row technique: a 2-year followup

Purpose. The purpose of this study was to evaluate the functional outcome and the tendon healing after arthroscopic double row rotator cuff repair of large and massive rotator cuff tears. Methods. 82 patients with a full-thickness large and massive rotator cuff tear underwent arthroscopic repair with double row technique. Results were evaluated by use of the UCLA, ASES, and Constant questionnaires, the Shoulder Strength Index (SSI), and range of motion. Follow-up time was 2 years. Magnetic resonance imaging (MRI) studies were performed on each shoulder preoperatively and 2 years after repair. Results. 100% of the patients were followed up. UCLA, ASES, and Constant questionnaires showed significant improvement compared with preoperatively (P < 0.001). Range of motion and SSI in flexion, abduction, and internal and external rotation also showed significant improvement (P < 0.001). MRI studies showed 24 cases of tear after repair (29%). Only 8 cases were a full-thickness tear. Conclusions. At two years of followup, in large and massive rotator cuff tears, an arthroscopic double row rotator cuff repair technique produces an excellent functional outcome and structural integrity.

Single-row vs. double-row arthroscopic rotator cuff repair: clinical and 3 Tesla MR arthrography results

BACKGROUND

Arthroscopic rotator cuff repair has become popular in the last few years because it avoids large skin incisions and deltoid detachment and dysfunction. Earlier arthroscopic single-row (SR) repair methods achieved only partial restoration of the original footprint of the tendons of the rotator cuff, while double-row (DR) repair methods presented many biomechanical advantages and higher rates of tendon-to-bone healing. However, DR repair failed to demonstrate better clinical results than SR repair in clinical trials. MR imaging at 3 Tesla, especially with intra-articular contrast medium (MRA), showed a better diagnostic performance than 1.5 Tesla in the musculoskeletal setting. The objective of this study was to retrospectively evaluate the clinical and 3 Tesla MRA results in two groups of patients operated on for a medium-sized full-thickness rotator cuff tear with two different techniques.

METHODS

The first group consisted of 20 patients operated on with the SR technique; the second group consisted of 20 patients operated on with the DR technique. All patients were evaluated at a minimum of 3 years after surgery. The primary end point was the re-tear rate at 3 Tesla MRA. The secondary end points were the Constant-Murley Scale (CMS), the Simple Shoulder Test (SST) scores, surgical time and implant expense.

RESULTS

The mean follow-up was 40 months in the SR group and 38.9 months in the DR group. The mean postoperative CMS was 70 in the SR group and 68 in the DR group. The mean SST score was 9.4 in the SR group and 10.1 in the DR group. The re-tear rate was 60% in the SR group and 25% in the DR group. Leakage of the contrast medium was observed in all patients.

CONCLUSIONS

To the best of our knowledge, this is the first report on 3 Tesla MRA in the evaluation of two different techniques of rotator cuff repair. DR repair resulted in a statistically significant lower re-tear rate, with longer surgical time and higher implant expense, despite no difference in clinical outcomes. We think that leakage of the contrast medium is due to an incomplete tendon-to-bone sealing, which is not a re-tear. This phenomenon could have important medicolegal implications. Level of evidence III. Treatment study: Case-control study.

Three-dimensional evaluation of cyclic displacement in single-row and double-row rotator cuff reconstructions under static external rotation

BACKGROUND

The double-row suture bridge repair was recently introduced and has demonstrated superior biomechanical results and higher yield load compared with the traditional double-row technique. It therefore seemed reasonable to compare this second generation of double-row constructs to the modified single-row double mattress reconstruction.

HYPOTHESIS

The repair technique, initial tear size, and tendon subregion will have a significant effect on 3-dimensional (3D) cyclic displacement under additional static external rotation of a modified single-row compared with a double-row rotator cuff repair.

STUDY DESIGN

Controlled laboratory study.

METHODS

Rotator cuff tears (small to medium: 25 mm; medium to large: 35 mm) were created in 24 human cadaveric shoulders. Rotator cuff repairs were performed as modified single-row or double-row repairs, and cyclic loading (10-60 N, 10-100 N) was applied under 20° of external rotation. Radiostereometric analysis was used to calculate cyclic displacement in the anteroposterior (x), craniocaudal (y), and mediolateral (z) planes with a focus on the repair constructs and the initial tear size. Moreover, differences in cyclic displacement of the anterior compared with the posterior tendon subregions were calculated.

RESULTS

Significantly lower cyclic displacement was seen in small to medium tears for the single-row compared with double-row repair at 60 and 100 N in the x plane (P = .001) and y plane (P = .001). The results were similar in medium to large tears at 100 N in the x plane (P = .004). Comparison of 25-mm versus 35-mm tears did not show any statistically significant differences for the single-row repairs. In the double-row repairs, lower gap formation was found for the 35-mm tears (P ≤ .05). Comparison of the anterior versus posterior tendon subregions revealed a trend toward higher anterior gap formation, although this was statistically not significant.

CONCLUSION

The tested single-row reconstruction achieved superior results in 3D cyclic displacement to the tested double-row repair. Extension of the initial rupture size did not have a negative effect on the biomechanical results of the tested constructs.

CLINICAL RELEVANCE

Single-row repairs with modified suture configurations provide comparable biomechanical strength to double-row repairs. Furthermore, as increased gap formation in the early postoperative period might lead to failure of the construct, a strong anterior fixation and restricted external rotation protocol might be considered in rotator cuff repairs to avoid this problem.

Arthroscopic rotator cuff repair: techniques in 2012

Techniques for arthroscopic partial-thickness and full-thickness RTC repairs continue to advance. When selecting an RTC repair technique, it is important to identify the tear pattern and adhere to the fundamentals of tendon mobilization and footprint preparation. Partial RTC tears greater than 50% in thickness can be reproducibly repaired with tear completion or transtendinous techniques with good clinical outcomes. Based on the available literature, small, less than 1-cm RTC tears can effectively be repaired with single-row techniques. Tears sized 1 cm to 3 cm can be repaired with either single-row, double-row, or transosseous-equivalent techniques based on surgeon comfort, tendon quality, and tissue mobility. Tears greater than 3 cm have shown superior results when transosseous-equivalent techniques are used. Further clinical studies are needed to definitively conclude the ideal RTC repair technique.

Superiority of bridging techniques with medial fixation on initial strength

PURPOSE

The purpose of our study was to evaluate the initial fixation strength of bridging techniques compared to other suture techniques for rotator cuff repair using a biomechanical animal model, which incorporated pretesting of intact tendons.

METHODS

Seventy-six fresh bovine shoulders were used for testing seven suture configurations including simple suture (SS), mattress suture (MS), Mason-Allen (MA), modified double row (mDR), SpeedBridge (SpB), SpeedBridge with medial fixation (mSpB), and double-mattress SutureBridge (dmSuB) techniques. Cyclic loading was performed with all intact bone-tendon complex before (pretest) and after repair of the tendon (main test) at the level of 10 and 180 N at 100 Hz with displacement-controlled ramps of ± 33 mm/s. The pretest was stopped after 200 cycles. For the main test, the loading scheme was continued for a maximum of 500 cycles or until failure.

RESULTS

The mean elongation of all 76 intact tendons measured at the pretest was 3.8 ± 0.6 mm (2.4-5.4 mm). No differences of gap formations at the 1st cycle were detected between SS, MS, MA, and mDR. SpB showed significant higher gap formations compared to all other suture techniques (p = 0.001). No significant differences were detected between mSpB and dmSuB, whereas both techniques were significant different when compared to the other groups (p < 0.05).

CONCLUSIONS

In this study, results showed that bridging techniques with medial fixations have superior initial repair strength compared to other suture techniques. Knowledge of initial fixation strength of rotator cuff repair techniques may be of informative value to the surgeon.

Functional outcomes and structural integrity after double-pulley suture bridge rotator cuff repair using serial ultrasonographic examination

BACKGROUND

We evaluated the integrity and functional outcomes of rotator cuff tear after performing the double-pulley suture bridge (DPSB) repair technique according to the tear size by using serial ultrasonographic examinations.

MATERIALS AND METHODS

The study included 41 consecutive arthroscopic rotator repairs using the DPSB technique. The average follow-up was 28 months. We completed the serial ultrasonographic examinations and compared the results with the functional outcome using the American Shoulder and Elbow Surgeons (ASES) score, the Constant score, the Korean Shoulder Scoring (KSS) system, and the University of California, Los Angeles (UCLA) score.

RESULTS

The overall retear rate was 19.5% (8 of 41), comprising 50% (2 of 4) for massive tears, 18% (2 of 11) for large tears, 17% (4 of 23) for medium tears, and no failures for small tears (0 of 3). The retear rate was 17.6% (6 of 34) after complete repair and 28.6% (2 of 7) after repair with gap formation. Seventy-five percent (6 of 8) of retears were identified within 6 months after operation and 25% (2 of 8) were identified more than 1 year after repair. The functional outcomes of the intact group and the retear group according to the ASES score, the Constant score, the KSS, and the UCLA score were 96, 93, 94, and 33, and 90, 82, 87, and 31, respectively (P > .05).

CONCLUSION

The overall retear rate after DPSB repair was 19.5% with 2 time periods of retear. The outcome improved independent of the tear size and the cuff integrity.

Extracorporeal shock wave therapy is not useful after arthroscopic rotator cuff repair

PURPOSE

Extracorporeal shock wave therapy (ESWT) is known to accelerate the healing of musculoskeletal tissue. The purpose of this study was to test the hypothesis that ESWT stimulates rotator cuff healing after arthroscopic repair.

METHODS

Seventy-one consecutive patients with a small- to large-sized rotator cuff tear underwent arthroscopic rotator cuff repair. The patients were randomized into two groups: 35 patients underwent ESWT at 6 weeks after surgery (ESWT group) and 36 patients did not (control group). Cuff integrity was evaluated with computed tomographic arthrography at 6 months after surgery. Constant and UCLA scores were measurable outcomes.

RESULTS

All patients were available for a minimum one-year follow-up. The mean age of the ESWT and control groups was 59.4 (SD: 7.7) and 58.6 years (SD: 7.8) (n.s.). There were no significant differences in tear size and repair method between the two groups (n.s.). The mean Constant and UCLA scores, respectively, increased from 54.6 to 90.6 (P < 0.001) and from 18.5 to 27.4 (P < 0.001) in the ESWT group, and from 58.9 to 89.3 (P < 0.001) and 18.5 to 27.4 in the control group. Computed tomographic arthrography was performed in 26 patients from the ESWT group and 24 from the control group, and cuff integrity was maintained in 46 out of 50 patients. Definite re-tear was observed in two patients of the ESWT group and four of the controls. There were no complications associated with ESWT.

CONCLUSION

This study failed to prove that ESWT stimulates rotator cuff healing after arthroscopic rotator cuff repair. Additional ESWT after rotator cuff repair could theoretically be advantageous, and it was proven to be safe in this study.

LEVEL OF EVIDENCE

II.

Influence of the initial rupture size and tendon subregion on three-dimensional biomechanical properties of single-row and double-row rotator cuff reconstructions

PURPOSE

Influence of the initial rotator cuff tear size and of different subregions of the SSP tendon on the cyclic loading behavior of a modified single-row reconstruction compared to a suture-bridging double-row repair.

METHODS

Artificial tears (25 and 35 mm) were created in the rotator cuff of 24 human cadaver shoulders. The reconstructions were performed as a single-row repair (SR) using a modified suture configuration or a suture-bridge double-row repair (DR). Radiostereometric analysis was used under cyclic loading (50 cycles, 10–180 N, 10–250 N) to calculate cyclic displacement in three different planes (anteroposterior (x), craniocaudal (y) and mediolateral (z) level). Cyclic displacement was recorded, and differences in cyclic displacement of the anterior compared to the posterior subregions of the tendon were calculated.

RESULTS

In small-to-medium tears (25 mm) and medium-to-large tears (35 mm), significant lower cyclic displacement was seen for the SR-reconstruction compared to the DR-repair at 180 N (p ≤ 0.0001; p = 0.001) and 250 N (p = 0.001; p = 0.007) in the x-level. These results were confirmed in the y-level at 180 N (p = 0.001; p = 0.0022) and 250 N (p = 0.005; p = 0.0018). Comparison of the initial tear sizes demonstrated significant differences in cyclic displacement for the DR technique in the x-level at 180 N (p = 0.002) and 250 N (p = 0.004). Comparison of the anterior versus the posterior subregion of the tendon revealed significant lower gap formation in the posterior compared to the anterior subregions in the x-level for both tested rotator cuff repairs (p ≤ 0.05).

CONCLUSIONS

The tested single-row repair using a modified suture configuration achieved superior results in three-dimensional measurements of cyclic displacement compared to the tested double-row suture-bridge repair. The results were dependent on the initial rupture size of the rotator cuff tear. Furthermore, significant differences were found between tendon subregions of the rotator cuff with significantly higher gap formation for the anterior compared to the posterior subregions.

Meta-analysis of Clinical and Radiographic Outcomes After Arthroscopic Single-Row Versus Double-Row Rotator Cuff Repair

Context:

Double-row rotator cuff repair methods have improved biomechanical performance when compared with single-row repairs.

Objective:

To review clinical outcomes of single-row versus double-row rotator cuff repair with the hypothesis that double-row rotator cuff repair will result in better clinical and radiographic outcomes.

Data Sources:

Published literature from January 1980 to April 2010. Key terms included rotator cuff, prospective studies, outcomes, and suture techniques.

Study Selection:

The literature was systematically searched, and 5 level I and II studies were found comparing clinical outcomes of single-row and double-row rotator cuff repair. Coleman methodology scores were calculated for each article.

Data Extraction:

Meta-analysis was performed, with treatment effect between single row and double row for clinical outcomes and with odds ratios for radiographic results. The sample size necessary to detect a given difference in clinical outcome between the 2 methods was calculated.

Results:

Three level I studies had Coleman scores of 80, 74, and 81, and two level II studies had scores of 78 and 73. There were 156 patients with single-row repairs and 147 patients with double-row repairs, both with an average follow-up of 23 months (range, 12-40 months). Double-row repairs resulted in a greater treatment effect for each validated outcome measure in 4 studies, but the differences were not clinically or statistically significant (range, 0.4-2.2 points; 95% confidence interval, –0.19, 4.68 points). Double-row repairs had better radiographic results, but the differences were also not statistically significant (P = 0.13). Two studies had adequate power to detect a 10-point difference between repair methods using the Constant score, and 1 study had power to detect a 5-point difference using the UCLA (University of California, Los Angeles) score.

Conclusions:

Double-row rotator cuff repair does not show a statistically significant improvement in clinical outcome or radiographic healing with short-term follow-up.

Revision rotator cuff repair

The management of patients with a failed rotator cuff repair is challenging. Revision arthroscopic repairs can be entertained in select patients when realistic outcomes are understood. Complete evaluation of the shoulder is needed to identify and treat potential confounding pain generators. The ability to determine if a recurrent tear is repairable is difficult, because there are no established criteria to make this determination. If a recurrent tear is found to be repairable, the results of the surgery are encouraging, although persistent limitations in shoulder function are common. Strategies to improve the rates of tendon healing should be used and include the use of stronger repair constructs, when possible, and implementation of a slower rehabilitation progression.

Rotator cuff: biology and current arthroscopic techniques

The present article summarizes current trends in arthroscopic rotator cuff repairs focusing on the used repair technique, potential influencing factors on the results, and long-term outcome after reconstruction of the rotator cuff. Moreover, different treatment options for the treatment for irreparable rotator cuff ruptures were described, and the results of additional augmentation of the repairs with platelet-rich plasma were critically analyzed. Based on the current literature, double-row repairs did not achieve superior clinical results compared to single-row repairs neither in the clinical results nor in the re-rupture rate. Multiple factors such as age, fatty infiltration, and initial rupture size might influence the results. If the rupture is not repairable, various options were described including cuff debridement, partial repair, tuberoplasty, or tendon transfers. The additional augmentation with platelet-rich plasma did not reveal any significant differences in the healing rate compared to conventional rotator cuff repairs.

LEVEL OF EVIDENCE

IV.

Single-row versus double-row arthroscopic repair in the treatment of rotator cuff tears: a prospective randomized clinical study

PURPOSE

The purpose of this study was to compare arthroscopic rotator cuff repair with single-row and double-row techniques because research has demonstrated the superiority of double-row repair from a biological and mechanical point of view but there is no evidence of clinical superiority.

METHODS

A total of 160 patients with a full-thickness rotator cuff tear underwent arthroscopic repair with suture anchors. They were randomised into two groups of 80 patients according to the repair technique: single-row (group 1) and double-row (group 2). Results were evaluated by use of the University of California, Los Angeles (UCLA), American Shoulder and Elbow Surgeons (ASES) and Constant questionnaires, the Shoulder Strength Index (SSI) and range of motion. Follow-up time was two years. Magnetic resonance imaging (MRI) studies were performed on each shoulder preoperatively and two years after repair.

RESULTS

One hundred per cent of the patients were followed up. All measurements showed significant improvement compared with the preoperative status. The UCLA score showed significant improvement in group 2. In over 30-mm tears UCLA and ASES showed significant differences. SSI showed significant improvement in group 2. Range of motion showed significant improvements in flexion and abduction in group 2. In under 30-mm tears group 2 showed also significant improvement in internal and external rotation. In MRI studies there were no significant differences.

CONCLUSIONS

At two years follow-up the double-row repair technique showed a significant difference in clinical outcome compared with single-row repair and this was even more significative in over 30-mm tears. No MRI differences were observed.

Does double-row rotator cuff repair improve functional outcome of patients compared with single-row technique? A systematic review

BACKGROUND

The advantage of single-row versus double-row arthroscopic rotator cuff repair techniques has been a controversial issue in sports medicine and shoulder surgery. There is biomechanical evidence that double-row techniques are superior to single-row techniques; however, there is no clinical evidence that the double-row technique provides an improved functional outcome.

HYPOTHESIS

When compared with single-row rotator cuff repair, double-row fixation, although biomechanically superior, has no clinical benefit with respect to retear rate or improved functional outcome.

STUDY DESIGN

Systematic review.

METHODS

The authors reviewed prospective studies of level I or II clinical evidence that compared the efficacy of single- and double-row rotator cuff repairs. Functional outcome scores included the American Shoulder and Elbow Surgeons (ASES) shoulder scale, the Constant shoulder score, and the University of California, Los Angeles (UCLA) shoulder rating scale. Radiographic failures and complications were also analyzed. A test of heterogeneity for patient demographics was also performed to determine if there were differences in the patient profiles across the included studies.

RESULTS

Seven studies fulfilled our inclusion criteria. The test of heterogeneity across these studies showed no differences. The functional ASES, Constant, and UCLA outcome scores revealed no difference between single- and double-row rotator cuff repairs. The total retear rate, which included both complete and partial retears, was 43.1% for the single-row repair and 27.2% for the double-row repair (P = .057), representing a trend toward higher failures in the single-row group.

CONCLUSION

Through a comprehensive literature search and meta-analysis of current arthroscopic rotator cuff repairs, we found that the single-row repairs did not differ from the double-row repairs in functional outcome scores. The double-row repairs revealed a trend toward a lower radiographic proven retear rate, although the data did not reach statistical significance. There may be a concerning trend toward higher retear rates in patients undergoing a single-row repair, but further studies are required.

Comparable biomechanical results for a modified single-row rotator cuff reconstruction using triple-loaded suture anchors versus a suture-bridging double-row repair

PURPOSE

To compare the biomechanical properties and footprint coverage of a single-row (SR) repair using a modified suture configuration versus a double-row (DR) suture-bridge repair in small to medium and medium to large rotator cuff tears.

METHODS

We created 25- and 35-mm artificial defects in the rotator cuff of 24 human cadaveric shoulders. The reconstructions were performed as either an SR repair with triple-loaded suture anchors (2 to 3 anchors) and a modified suture configuration or a modified suture-bridge DR repair (4 to 6 anchors). Reconstructions were cyclically loaded from 10 to 60 N. The load was increased stepwise up to 100, 180, and 250 N. Cyclic displacement and load to failure were determined. Furthermore, footprint widths were quantified.

RESULTS

In the 25-mm rupture, ultimate load to failure was 533 ± 107 N for the SR repair and 681 ± 250 N for the DR technique (P ≥ .21). In the 35-mm tear, ultimate load to failure was 792 ± 122 N for the SR reconstruction and 891 ± 174 N for the DR reconstruction (P ≥ .28). There were no statistically significant differences for both tested rupture sizes. Cyclic displacement showed no significant differences between the tested configurations at 60 N (P = .563), 100 N (P = .171), 180 N (P = .211), and 250 N (P = .478) for the 25-mm tear. For the 35-mm tear, cyclic displacement showed significantly lower gap formation for the SR reconstruction at 180 N (P = .037) and 250 N (P = .020). No significant differences were found at 60 N (P = .296) and 100 N (P = .077). A significantly greater footprint width (P = .028) was seen for the DR repair (16.2 mm) compared with the SR repair (13.8 mm). However, both reconstructions were able to achieve complete footprint coverage compared with the initial footprint.

CONCLUSIONS

The tested SR repair using a modified suture configuration was similar in load to failure and cyclic displacement to the DR suture-bridge technique independent of the tested initial sizes of the rupture. The tested DR repair consistently restored a larger footprint than the SR method. However, both constructs achieved complete footprint coverage.

CLINICAL RELEVANCE

SR repairs with modified suture configurations might combine the biomechanical advantages and increased footprint coverage that are described for DR repairs without increasing the overall costs of the reconstruction.

Clinical outcome and imaging of arthroscopic single-row and double-row rotator cuff repair: a prospective randomized trial

PURPOSE

The purpose of this study was to compare the clinical and imaging outcomes of single-row and double-row suture anchor fixation in arthroscopic rotator cuff repair with emphasis on analysis of the effect of various tear size on repair integrity.

METHODS

Fifty-three patents were randomized to either single-row or double-row rotator cuff repair at the time of surgical intervention. The clinical results were evaluated by applying the UCLA score and the ASES index and assessing muscle strength in abduction and external rotation with a minimum 2-year follow-up. The postoperative rotator cuff integrity was evaluated by magnetic resonance arthrography at 6-month and minimum 2-year follow-up.

RESULTS

We enrolled 27 patients in the single-row group and 26 patients in the double-row group. Statistically, the UCLA score; the ASES index; and muscle strength were significantly increased in both groups after surgery, but there was no significant difference between the 2 groups. At minimum 2-year follow-up, intact rotator cuffs were found in 17 patients in the single-row group and 20 in the double-row group, based on magnetic resonance arthrography results. Overall, there was no significant difference in postoperative structural integrity between the 2 groups at 6-month and 2-year follow-up. In patients with tear size larger than 3 cm, the muscle strength of the shoulder was significantly better in the double-row group. For the final imaging results, regardless of the tear size, there was no difference between the single-row and double-row groups.

CONCLUSIONS

Arthroscopic rotator cuff repair with double-row fixation showed better shoulder strength in patients with larger tear size (>3 cm) in comparison with single-row fixation. However, the imaging results showed no significant difference in cuff integrity in both groups in patients with any tear size at 6-month and minimum 2-year follow-up.

LEVEL OF EVIDENCE

Level II, lesser-quality randomized control trial.

A biomechanical analysis of point of failure during lateral-row tensioning in transosseous-equivalent rotator cuff repair

PURPOSE

The purpose of this study was to determine the maximum load and point of failure of the construct during tensioning of the lateral row of a transosseous-equivalent (TOE) rotator cuff repair.

METHODS

In 6 fresh-frozen human shoulders, a TOE rotator cuff repair was performed, with 1 suture from each medial anchor passed through the tendon and tied in a horizontal mattress pattern. One of 2 limbs from each of 2 medial anchors was pulled laterally over the tendon. After preparation of the lateral bone for anchor placement, the 2 limbs were passed through the polyether ether ketone (PEEK) eyelet of a knotless anchor and tied to a tensiometer. The lateral anchor was placed into the prepared bone tunnel but not fully seated. Tensioning of the lateral-row repair was simulated by pulling the tensiometer to tighten the suture limbs as they passed through the eyelet of the knotless anchor. The mode of failure and maximum tension were recorded. The procedure was then repeated for the second lateral-row anchor.

RESULTS

The mean load to failure during lateral-row placement in the TOE model was 80.8 ± 21.0 N (median, 83 N; range, 27.2 to 115.8 N). There was no statistically significant difference between load to failure during lateral-row tensioning for the anterior and posterior anchors (P = .84). Each of the 12 constructs failed at the eyelet of the lateral anchor. Retrieval analysis showed no failure of the medial anchors, no medial suture cutout through the rotator cuff tendon, and no signs of gapping at the repair site.

CONCLUSIONS

Our results suggest that the medial-row repair does not appear vulnerable during tensioning of the lateral row of a TOE rotator cuff repair with the implants tested. However, surgeons should exercise caution when tensioning the lateral row, especially when lateral-row anchors with PEEK eyelets are implemented.

CLINICAL RELEVANCE

For this repair construct, the findings suggest that although the medial row is not vulnerable during lateral-row tensioning of a TOE rotator cuff repair, lateral-row anchors with PEEK eyelets appear vulnerable to early failure.

Bone marrow-derived mesenchymal stem cells obtained during arthroscopic rotator cuff repair surgery show potential for tendon cell differentiation after treatment with insulin

PURPOSE

The purpose of this study was to determine whether a one-time physiologic dose of insulin when compared with the growth factors insulin-like growth factor 1, β-fibroblastic growth factor, and growth differentiation factor 5 is capable of differentiating bone marrow-derived mesenchymal stem cells (MSCs) into tendon.

METHODS

Eleven patients undergoing arthroscopic rotator cuff repair consented to undergo aspiration of bone marrow. A dose-response curve was calculated to determine the optimal dose of insulin needed to differentiate MSCs into tendon. After purification of bone marrow in the operating room, MSCs were exposed to either insulin or tendon-inducing growth factors or were left untreated to serve as a control. The potential for MSCs in each of these groups to differentiate into tendon was evaluated with a multistep process that included determination of the genetic upregulation for tendon-specific proteins, confirmation that the levels of these proteins were actually increased, staining of the MSCs with antibodies for these proteins to ensure that they were expressed on the cell surface, and finally, evaluation of cell morphology to verify the MSCs' tendon-like appearance.

RESULTS

MSCs treated with insulin showed increased gene expression of tendon-specific markers (P < .05), increased content of tendon-specific proteins (P < .05), and increased receptors on the cell surface (P < .05) compared with control cells. Histologic analysis showed a tendon-like appearance compared with the control cells.

CONCLUSIONS

Bone marrow-derived MSCs treated with a single physiologic dose of insulin differentiated into cells with characteristics consistent with tendon.

CLINICAL RELEVANCE

The potential for MSCs to differentiate into tendon after a 1-time dose of insulin may assist in developing practical biologic options for augmentation of rotator cuff repairs.

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.

Arthroscopic rotator cuff repair using a suture bridge technique: is the repair integrity actually maintained?

BACKGROUND

Suture bridge repair has been recognized to have superior biomechanical characteristics, as shown in previous biomechanical studies. However, it is not clear whether the tendon heals better in vivo after suture bridge repair.

PURPOSE

To evaluate the clinical results and repair integrity after arthroscopic rotator cuff repair using a suture bridge technique for patients with rotator cuff tears.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

One hundred twenty-three shoulders (120 patients) that underwent arthroscopic suture bridge repair for full-thickness rotator cuff tear were enrolled for this study. The mean duration of follow-up was 25.2 months (range, 16-34 months). The postoperative repair integrity was analyzed with use of magnetic resonance imaging (MRI) in 87 shoulders. According to the retear patterns on postoperative MRI, the cases were divided into type 1 (failure at the original repair site) or 2 (failure around the medial row).

RESULTS

At the last follow-up, the University of California at Los Angeles (UCLA) score improved from the preoperative mean of 13.2 points to 29.7 points (P < .001). The rotator cuff was completely healed in 58 (66.7%) of the 87 shoulders, and there was a recurrent tear in 29 shoulders (33.3%). The incidence of retear tended to increase with age older than 60 years at the time of surgery (P = .002). When there was a larger intraoperative tear, the rate of retear was also higher (P = .002). When the severity of preoperative fatty degeneration of the cuff muscles was higher, there was a greater chance of a recurrent tear (P < .001). The retear patterns on postoperative MRI in 29 shoulders with recurrent failures were classified as type 1 in 12 shoulders (41.4%) and type 2 in 17 shoulders (58.6%). The preoperative cuff tear size did not have an influence on retear patterns (P = .236), but the percentage of type 1 retear increased with the severity of fatty degeneration or muscle atrophy (P = .041, .023).

CONCLUSION

Arthroscopic suture bridge repair of full-thickness rotator cuff tears led to a relatively high rate of recurrent defects. However, the mean 25-month follow-up demonstrated excellent pain relief and improvement in the ability to perform the activities of daily living, despite the structural failures. The factors affecting tendon healing were the patient's age, the size and extent of the tear, and the presence of fatty degeneration in the rotator cuff muscle. The retear in cases with a suture bridge technique tended to be more frequently at the musculotendinous junction.

Contact area and pressure in suture bridge rotator cuff repair using knotless lateral anchors

PURPOSE

To evaluate whether the use of knotless lateral anchors in a suture bridge construct produces better contact area and pressure parameters than a suture bridge construct with standard lateral anchors that require knots or a double-row repair. The hypothesis was that knotless lateral anchors would produce better contact area and pressure parameters than the other two constructs.

METHODS

A total of fifteen matched pairs of cadaveric shoulders were divided into three groups. In Group 1, a suture bridge using knotless anchors for the lateral row was performed on five shoulders. A suture bridge using standard lateral row anchors that require knots was performed on the contralateral shoulders. In Group 2, suture bridge with knotless lateral row anchors was compared with double-row repair. In Group 3, suture bridge using standard lateral row anchors was compared with double-row repair. The contact conditions of the rotator cuff footprint were measured using pressure-sensitive film.

RESULTS

There were no statistically significant differences between any of the techniques regarding contact area F(2, 15.7) = 3.09, P = 0.07 or mean contact pressure F(2, 15.1) = 2.35, P = 0.12. A post hoc power analysis suggests differences between techniques are likely less than 91-113 mm(2) for area and 0.071-0.089 N for pressure.

CONCLUSIONS

The use of knotless anchors in the lateral row of a suture bridge repair did not increase the footprint contact area or contact pressure when compared to a suture bridge repair requiring knots laterally or to a double-row repair.

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

BACKGROUND

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

HYPOTHESIS

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

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

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

RESULTS

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

CONCLUSION

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

Biomechanical evaluation of four different transosseous-equivalent/suture bridge rotator cuff repairs

PURPOSE

Evaluate the biomechanical behavior of four variants of the transosseous-equivalent/suture bridge (TOE/SB) repair.

METHODS

Four suture bridge (SB) constructs were created using 24 sheep infraspinatus tendon-humerus constructs (n = 6 per technique). The groups were (1) Knotted Standard Suture Bridge (Standard SB)--suture bridge with two medial mattress stitches, (2) Knotted Double Suture Bridge (Double SB)--four medial mattress stitches, (3) Untied Suture Bridge with Medial FT Anchors (Untied SB with FT)--two medial mattress stitches without knots, and (4) Untied Suture Bridge with PushLocks (Untied SB with Pushlocks)--two medial mattress stitches without knots. The contact area footprint was measured with an electronic pressure film prior to dynamic mechanical testing for gapping and testing to failure.

RESULTS

The Double SB produced the greatest contact area footprint compared to the other techniques, which did not differ. The Double SB repair with a mean failure load of 456.9N was significantly stronger than the Untied SB with Pushlocks repair at 300N (P = 0.023), the standard SB repair at 295N (P = 0.019), and lastly the Untied SB with FT repair at 284N (P = 0.011). No differences were detected between the two mattress stitch standard SB repair with knots and the knotless two mattress stitch repairs (Untied SB with FT and Untied SB with Pushlocks). Gaps developed during cyclic loading in all repairs apart from the Double SB repair.

CONCLUSIONS

The transosseous-equivalent/suture bridge repair with 4 stitches tied in the medial row and maximal lateral suture strand utilization (Double SB) outperformed all other repairs in terms of failure load, tendon-bone contact, and gapping characteristics. The presence of knots in the medial row did not change tendon fixation with respect to failure load, contact area or gapping characteristics.

Arthroscopic treatment of rotator cuff disease

The goal of this article is to summarize the current concepts on rotator cuff disease with an emphasis on arthroscopic treatment. Most rotator cuff tears are the result of an ongoing attritional process. Once present, a tear is likely to gradually increase in size. Partial-thickness and subscapularis tears can both be successfully treated arthroscopically if conservative management fails. Partial tears involving greater than 50% of tendon thickness should be repaired. Articular-sided partial tears involving less than 50% of the rotator cuff can reliably be treated with debridement. A more aggressive approach should be considered for low-grade tears (<50%) if they occur on the bursal side. Biomechanical and anatomic studies have shown clear superiority with dual-row fixation compared with single-row techniques. However, current studies have yet to show clear clinical advantage with dual-row over single-row repairs. Biceps tenotomy or tenodesis can reliably provide symptomatic improvement in patients with irreparable massive tears. True pseudoparalysis of the shoulder is a contraindication to this procedure alone and other alternatives should be considered.

Arthroscopic rotator cuff repair using a single-row of triple-loaded suture anchors with a modified suture configuration

Achieving an adequate restoration of the muscle-tendon-bone unit and the anatomical footprint is essential for a successful outcome in open and arthroscopic rotator cuff repair. The described suture grasping technique using triple-loaded suture anchors might combine high initial fixation strength with good footprint coverage. It describes two mattress' stitches medial at the articular margin of the tendon. Additionally, a third mattress stitch is performed laterally to increase footprint contact and avoid dog-ear deformity. The triple-mattress repair is easy to perform and might be a good alternative in either arthroscopic or open rotator cuff repair.

Single-row repair versus double-row repair of full-thickness rotator cuff tears

PURPOSE

The purpose of this meta-analysis was to assess whether there are differences in the outcomes between single-row and double-row rotator cuff repair.

METHODS

Using MEDLINE, SCOPUS, SCIRUS, CINAHL, and the Cochrane Library, as well as a hand search, we searched for articles comparing single-row and double-row rotator cuff repair that were published before September 2009. The controlled clinical studies that met the inclusion and exclusion criteria were assessed for quality of methodology. Two of the authors performed this review and assessment. Any disagreements were resolved by the third author.

RESULTS

Three randomized controlled studies and two controlled clinical cohort studies were included in this meta-analysis. These studies were assessed as having a moderate to high level of evidence. The results showed that double-row repair improved tendon healing and provided greater external rotation but with significantly increased operative time. Furthermore, this study found that double-row repair decreased the recurrence rate. However, there were no statistically significant differences found in shoulder function as assessed by Constant score; American Shoulder and Elbow Surgeons (ASES) score; University of California, Los Angeles (UCLA) score; Western Ontario Rotator Cuff (WORC) index; Disabilities of the Arm, Shoulder and Hand (DASH) score; muscle strength; forward flexion; internal rotation; patient satisfaction; return to work; and adverse events.

CONCLUSIONS

Despite the fact that double-row repair shows a significantly higher rate of tendon healing and greater external rotation than does single-row repair, there is no significant improvement in shoulder function, muscle strength, forward flexion, internal rotation, patient satisfaction, or return to work.

LEVEL OF EVIDENCE

Level II, meta-analysis of Level I and Level II studies.

Early structural and functional outcomes for arthroscopic double-row transosseous-equivalent rotator cuff repair

BACKGROUND

The arthroscopic double-row transosseous-equivalent (TOE) rotator cuff repair is growing in popularity. The current body of literature supports this technique; however, the number of patients in these studies is relatively small. The authors conducted this study to learn more about the natural history of this construct in a large sample of patients.

HYPOTHESIS

The double-row TOE rotator cuff repair will have an acceptable structural failure rate with improved clinical outcomes at 1-year follow-up.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between June 2006 and October 2007, 225 patients underwent an all-arthroscopic rotator cuff repair at 2 surgical centers. A total of 155 TOE primary rotator cuff repairs were performed, and 154 of these patients met the inclusion criteria. Assessment of structural integrity was based on evaluation of postoperative magnetic resonance imaging or computed tomography arthrogram at a minimum of 12 months after surgery. The Constant scores, visual analog pain scale, range of motion, strength, and complications were the clinical outcomes analyzed for the study. Seventeen patients (of 154) had postoperative shoulder stiffness at follow-up.

RESULTS

The 154 patients were clinically and radiologically evaluated at a mean of 15 months postoperatively (range, 12-26.1 months). The study included 47 small (30.5%), 89 large (57.1%), and 19 massive (12.3%) rotator cuff tears. Analysis of postoperative imaging demonstrated that 92%, 83%, and 84% of the small, large, and massive rotator cuff tears, respectively, were intact. The mean Constant score improved from 44.42 points preoperatively to 80.47 points postoperatively (P < .001). The mean preoperative pain score improved from 3.83 to 12.77 (P < .001) postoperatively. The mean forward flexion improved from 123.06° preoperatively to 162.39° postoperatively (P < .001). Seventeen patients (of 154) had postoperative shoulder stiffness at follow-up.

CONCLUSION

The short-term results of this study indicate that the clinical outcomes and structural integrity of TOE double-row rotator cuff repair (the suture-bridge technique) have results that compare favorably with those reported for other double-row suture anchor techniques employed in rotator cuff repairs. Long-term follow-up will be necessary to determine if the durability of these repairs and the structural integrity of these constructs maintain their performance over time.