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

Treatment of rotator cuff tears: a systematic review and meta-analysis

BACKGROUND

There is ongoing controversy regarding optimal treatment for full-thickness rotator cuff tears. Given that the evidence surrounding the use of various treatment options has expanded, an overall assessment is required.

OBJECTIVES

The following were compared to determine which resulted in improved patient-reported function, pain, and reoperation rates for each: (1) double-row (DR) fixation and single-row (SR) fixation in arthroscopic cuff repair; (2) latissimus dorsi transfer (LDT) with lower trapezius transfer (LTT), partial rotator cuff repair, and superior capsular reconstruction (SCR); and (3) early and late surgical intervention.

METHODS

Medline, Embase, and Cochrane were searched through to April 20, 2021. Additional studies were identified from reviews. The following were included: (1) All English-language randomized controlled trials (RCTs) in patients ≥18 years of age comparing SR and DR fixation, (2) observational studies comparing LDT with LTT, partial repair, and SCR, and (3) observational studies comparing early vs. late treatment of full-thickness rotator cuff tears.

RESULTS

A total of 15 RCTs (n = 1096 randomized patients) were included in the meta-analysis of SR vs. DR fixation. No significant standardized mean differences in function (0.08, 95% confidence interval [CI] -0.09, 0.24) or pain (-0.01, 95% CI -0.52, 0.49) were observed. There was a difference in retear rates in favor of DR compared with SR fixation (RR 1.56, 95% CI 1.06, 2.29). Four studies were included in the systematic review of LDT compared with a surgical control. LDT and partial repair did not reveal any differences in function (-1.12, 95% CI -4.02, 1.78) on comparison. A single study compared arthroscopically assisted LDT to LTT and observed a nonstatistical difference in the Constant score of 14.7 (95% CI -4.06, 33.46). A single RCT compared LDT with SCR and revealed a trend toward superiority for the Constant score with SCR with a mean difference of -9.6 (95% CI -19.82, 0.62). Comparison of early vs. late treatment revealed a paucity of comparative studies with varying definitions of "early" and "late" treatment, which made meaningful interpretation of the results difficult.

CONCLUSION

DR fixation leads to similar improvement in function and pain compared with SR fixation and results in a higher healing rate. LDT transfer yields results similar to those from partial repair, LTT, and SCR in functional outcomes. Further study is required to determine the optimal timing of treatment and to increase confidence in these findings. Future trials of high methodologic quality comparing LDT with LTT and SCR are required.

[Rotator cuff repair: single- vs double-row. Clinical and biomechanical results]

BACKGROUND

The goal of rotator cuff repair is a high initial mechanical stability as a requirement for adequate biological recovery of the tendon-to-bone complex. Notwithstanding the significant increase in publications concerning the topic of rotator cuff repair, there are still controversies regarding surgical technique.

OBJECTIVES

The aim of this work is to present an overview of the recently published results of biomechanical and clinical studies on rotator cuff repair using single- and double-row techniques.

MATERIALS AND METHODS

The review is based on a selective literature research of PubMed, Embase, and the Cochrane Database on the subject of the clinical and biomechanical results of single- and double-row repair.

RESULTS

In general, neither the biomechanical nor the clinical evidence can recommend the use of a double-row concept for the treatment for every rotator cuff tear. Only tears of more than 3 cm seem to benefit from better results on both imaging and in clinical outcome studies compared with the use of single-row techniques.

CONCLUSIONS

Despite a significant increase in publications on the surgical treatment of rotator cuff tears in recent years, the clinical results were not significantly improved in the literature so far. Unique information and algorithms, from which the optimal treatment of this entity can be derived, are still inadequate. Because of the cost-effectiveness and the currently vague evidence, the double-row techniques cannot be generally recommended for the repair of all rotator cuff tears.

Reconstruction of 25 and 50 % subscapularis tears: a single anchor with a double-mattress suture is sufficient for the reconstruction

PURPOSE

Evaluation of the biomechanical performance of repairs of 25 % (Fox/Romeo II) and 50 % (Fox/Romeo III) full-thickness subscapularis tears using a single-suture anchor.

METHODS

Six pairs of human cadaver specimens were used for the testing. Artificial subscapularis tears were created in order to simulate a 25 % (6) and a 50 % (6) full-thickness tear. The reconstructions were made with a double-loaded suture anchor (5.5-mm Bio-Corkscrew with two No. 2 Fiberwire) creating a double-mattress suture repair. Reconstructions were cyclically loaded from 10 to 60 N. The load was increased stepwise up to 100 and 180 N. Cyclic displacement (means + standard dev.) as well as load-to-failure was determined, and mode of failure was recorded.

RESULTS

In the reconstructed shoulders at 60 N, a mean cyclic displacement of 3.2 ± 0.7 mm was found in the 25 % tear, 2.6 ± 0.6 mm in the 50 % tear. At 100 N, 5.1 ± 1.2 mm was seen in the 25 % tear and 4.3 ± 0.3 mm in the 50 % tear. At highest load of 180 N, 7.6 ± 2.2 mm was recorded in the 25 % tear, 6.5 ± 0.8 mm was found in the 50 % tear. Ultimate failure load was 486 ± 167 N in the 25 % tear and 455 ± 213 N in the 50 % tear. Statistically significant differences between the tested repairs were seen neither in cyclic displacement nor in ultimate failure loads (p > 0.05). Mode of failure revealed bone fractures and anchor pull-out as major cause in the 25 % group, whereas failure of the suture-tendon interface was the major cause of failure in the 50 % group.

CONCLUSIONS

Subscapularis repair using a single double-loaded suture anchor revealed similar biomechanical performance in 25 % compared to 50 % full-thickness subscapularis tears. With increased tear size, however, an optimized suture-tendon interface seems to become more relevant in order to decrease failure rate of the repair.

CLINICAL RELEVANCE

A single double-loaded suture anchor provides sufficient biomechanical strength even in Fox/Romeo grade III tears of the subscapularis tendon. However, a modified suture configuration is recommended, especially in grade III tears as the suture-tendon interface is the weakest point of the construct.

Radiostereometric Evaluation of Tendon Elongation After Distal Biceps Repair

BACKGROUND

Operative repair of distal biceps tendon ruptures has shown successful outcomes. However, little is known about the amount of tendon or repair site lengthening after repair.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate distal biceps tendon repair via intratendinous radiostereometric analysis to analyze tendon lengthening at different time intervals of healing. The hypothesis was that there is significant lengthening after repair.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Eleven patients with distal biceps ruptures requiring operative repair were recruited. During repair, two 2-mm tantalum beads with laser-etched holes were sutured to the distal biceps tendon. Beads were evaluated via computed tomography scans immediately postoperatively and at 16 weeks. Radiographs were obtained at time 0 and then at 4, 8, and 16 weeks postoperatively. Measurements were made using the button-to-bead and bead-to-bead distances to assess repair site elongation as well as tendon elongation over time. After final follow-up, patients filled out the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire and underwent ultrasound to confirm the integrity of the tendon.

RESULTS

Ten patients had complete ruptures, with 1 having a partial rupture that underwent completion of the tear and subsequent repair. All patients showed statistically significant lengthening after surgery. The mean amount of tendon lengthening after surgery was 22.8 mm (range, 11.2-30.9 mm; P < .05), and the repair site lengthened a mean 17.0 mm (range, 9.6-30.6 mm; P < .05) from surgery to final follow-up. The greatest change in lengthening was noted between time 0 and week 4 (mean, 11.3 mm; P < .05), with the least amount of lengthening between weeks 8 and 16 (mean, 2.6 mm; P < .05). The mean DASH score was 11.2. Final ultrasound evaluations found all tendons to be in continuity.

CONCLUSION

All patients undergoing distal biceps tendon repair have significant elongation after surgery, with the greatest amount of lengthening seen in the early postoperative period.

Advances in biology and mechanics of rotator cuff repair

High initial fixation strength, mechanical stability and biological healing of the tendon-to-bone interface are the main goals after rotator cuff repair surgery. Advances in the understanding of rotator cuff biology and biomechanics as well as improvements in surgical techniques have led to the development of new strategies that may allow a tendon-to-bone interface healing process, rather than the formation of a fibrovascular scar tissue. Although single-row repair remains the most cost-effective technique to address a rotator cuff tear, some biological intervention has been recently introduced to improve tissue healing and clinical outcome of rotator cuff repair. Animal models are critical to ensure safety and efficacy of new treatment strategies; however, although rat shoulders as well as sheep and goats are considered the most appropriate models for studying rotator cuff pathology, no one of them can fully reproduce the human condition. Emerging therapies involve growth factors, stem cells and tissue engineering. Experimental application of growth factors and platelet-rich plasma demonstrated promising results, but has not yet been transferred into standardized clinical practice. Although preclinical animal studies showed promising results on the efficacy of enhanced biological approaches, application of these techniques in human rotator cuff repairs is still very limited. Randomized controlled clinical trials and post-marketing surveillance are needed to clearly prove the clinical efficacy and define proper indications for the use of combined biological approaches. The following review article outlines the state of the art of rotator cuff repair and the use of growth factors, scaffolds and stem cells therapy, providing future directions to improve tendon healing after rotator cuff repair.

LEVEL OF EVIDENCE

Expert opinion, Level V.

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.

Does transosseous-equivalent rotator cuff repair biomechanically provide a "self-reinforcement" effect compared with single-row repair?

BACKGROUND

Transosseous-equivalent (TOE) rotator cuff repair has been theorized to be "self-reinforcing" against potentially destructive and increasing tendon loads. The goal of this study was to biomechanically verify and characterize the effect of increasing tendon load on frictional resistance over a repaired footprint for single-row (SR) and TOE repair techniques.

METHODS

In 10 fresh frozen human shoulders, TOE and SR supraspinatus tendon repairs were performed in each specimen. For all repairs, a pressure sensor was secured at the tendon-footprint interface. The supraspinatus tendon was loaded with 0, 20, 40, 60, and 80 N at 0° and 30° abduction. Paired t tests and multivariate regression analyses were used for comparisons.

RESULTS

The SR repair had significant increases in footprint contact force, area, and pressure between each and all tendon-loading conditions (P < .05). The TOE repair similarly demonstrated increases in footprint contact force with increasing tendon load (P < .05). Comparing between repairs, TOE repair had more footprint contact force, area, pressure, and peak pressure at each load for both abduction angles (P < .05). With increasing load, the TOE repair had a significantly higher progression (slope) of footprint force and pressure compared with the SR repair.

CONCLUSIONS

Self-reinforcing capacity in rotator cuff repair has been biomechanically characterized and verified. The TOE repair, with tendon-bridging sutures fixed medially and spanning the footprint, provides disproportionately more progressive footprint frictional resistance with increasing tendon loads compared with the SR repair secured over isolated fixation points. This self-reinforcing effect could help sustain structural integrity and potentially improve healing biology.

Is double-row rotator cuff repair clinically superior to single-row rotator cuff repair: a systematic review of overlapping meta-analyses

PURPOSE

Multiple meta-analyses of randomized clinical trials, the highest available level of evidence, have been conducted to determine whether double-row (DR) or single-row (SR) rotator cuff repair (RCR) provides superior clinical outcomes and structural healing; however, results are discordant. The purpose of this study was to conduct a systematic review of meta-analyses comparing SR and DR RCR to elucidate the cause of discordance and to determine which meta-analysis provides the current best available evidence.

METHODS

In this study we evaluated available scientific support for SR versus DR RCR by systematically reviewing the literature for published meta-analyses. Data were extracted from these meta-analyses for patient outcomes and structural healing. Meta-analysis quality was assessed with the Oxman-Guyatt and Quality of Reporting of Meta-analyses (QUOROM) systems. The Jadad algorithm was then applied to determine which meta-analyses provided the highest level of evidence.

RESULTS

Eight meta-analyses met the eligibility criteria: 4 including Level I evidence and 4 including both Level I and Level II evidence. Six meta-analyses found no differences between SR and DR RCR for patient outcomes, whereas 2 favored DR RCR for tears greater than 3 cm. Two meta-analyses found no structural healing differences between SR and DR RCR, whereas 3 found DR repair to be superior for tears greater than 3 cm and 2 found DR repair to be superior for all tears. Four meta-analyses had low Oxman-Guyatt scores (<3) indicative of major flaws. After application of the Jadad algorithm, 3 concordant high-quality meta-analyses were selected, all of which found significantly better structural healing with DR compared with SR RCR.

CONCLUSIONS

According to this systematic review of overlapping meta-analyses comparing SR and DR RCR, the current highest level of evidence suggests that DR RCR provides superior structural healing to SR RCR.

LEVEL OF EVIDENCE

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

Biomechanical effects of a 2 suture-pass medial inter-implant mattress on transosseous-equivalent rotator cuff repair and considerations for a "technical efficiency ratio"

BACKGROUND

Rotator cuff repair involving fewer tendon suture passes without compromising biomechanical performance would represent a technical advancement. An inter-implant "medial pulley-mattress" transosseous-equivalent (MP-TOE) repair requiring fewer tendon suture-passes was hypothesized to provide equivalent biomechanical characteristics compared to the control.

METHODS

In 6 human cadaveric shoulders, a transosseous-equivalent (TOE) repair (control) was performed utilizing 2 separate medial mattresses resulting in 4 tendon-bridging sutures. In 6 matched-pairs, 2 single-loaded anchors were used to create a medial inter-implant mattress construct (all sutures shuttled in 1 tendon pass per anchor)-after knot-tying, the same tendon-bridging pattern as the control was created. A materials testing machine cyclically loaded each repair from 10-180 N for 30 cycles; each repair subsequently underwent failure testing. Gap and strain were measured with a video digitizing system. A "technical efficiency ratio" (TER) was defined as: (#knots + #suture passes + #suture limbs)/#fixation points.

RESULTS

Cyclic and failure testing demonstrated no significant differences between constructs. Gap formation at cycle 30 was 5.3 ± 0.8 mm (TOE) and 5.0 ± 0.3 mm (MP-TOE) (P = .62). Cycle 30 anterior strain values were -16.0 ± 7.3% (TOE) and -15.8 ± 6.6% (MP-TOE) (P = .99). Yield loads were 208.7 ± 2.7 N (TOE) and 204.0 ± 1.3 N (MP-TOE) (P = .17). Mode of failure demonstrated less tendon cut-out with the MP-TOE repair. The MP-TOE repair has a TER of 2.0 vs 2.5 for the control.

CONCLUSION

The MP-TOE repair requiring fewer tendon suture passes, yet creating an additional inter-implant mattress configuration, is biomechanically equivalent to the original TOE technique, and may limit failure with improved medial load-sharing capacity. A TER may help quantify technical ease and help standardize comparisons between repair techniques.

Biomechanical comparison of single-row, double-row, and transosseous-equivalent repair techniques after healing in an animal rotator cuff tear model

The transosseous-equivalent (TOE) rotator cuff repair technique increases failure loads and contact pressure and area between tendon and bone compared to single-row (SR) and double-row (DR) repairs, but no study has investigated if this translates into improved healing in vivo. We hypothesized that a TOE repair in a rabbit chronic rotator cuff tear model would demonstrate a better biomechanical profile than SR and DR repairs after 12 weeks of healing. A two-stage surgical procedure was performed on 21 New Zealand White Rabbits. The right subscapularis tendon was transected and allowed to retract for 6 weeks to simulate a chronic tear. Repair was done with the SR, DR, or TOE technique and allowed to heal for 12 weeks. Cyclic loading and load to failure biomechanical testing was then performed. The TOE repair showed greater biomechanical characteristics than DR, which in turn were greater than SR. These included yield load (p < 0.05), energy absorbed to yield (p < 0.05), and ultimate load (p < 0.05). For repair of a chronic, retracted rotator cuff tear, the TOE technique was the strongest biomechanical construct after healing followed by DR with SR being the weakest.

Biomechanical validation of rotator cuff repair techniques and considerations for a "technical efficiency ratio"

Biomechanical studies are commonly used to validate new or modified rotator cuff repair techniques. Additional knots, more tendon suture passes, and obligatory suture management requirements are often the "cost" for improved biomechanical results. This cost can amount to increased technical difficulty and surgical times. However, technical ease or difficulty as a measurable variable has not been quantified. A basic measure for technical ease would allow surgeons the ability to objectively assess and compare rotator cuff repair practicality and potentially help in the design of future studies to standardize repair techniques alongside biomechanical measures. A proposed rotator cuff repair "technical efficiency ratio" is defined as follows: (No. of knots + No. of tendon suture passes + No. of suture limbs)/No. of pilot holes created. This can give a measure of "work" or utility achieved per fixation point created for a particular type of repair (e.g., single or double row), with a smaller number representing relatively more efficiency per anchor or fixation point used. If repairs validated in the laboratory are too cumbersome to perform in vivo from a practical standpoint, technical ease should be a prerequisite measure, and the success of a repair technique should not necessarily be based on biomechanics alone.