Arthroscopic Superior Capsular Reconstruction with Achilles Tendon Allograft for Massive and Revision Rotator Cuff Tears

Superior Capsular Reconstruction with the mini open key-hole Technique using Achilles allograft demonstrates favorable outcomes for patients with preoperative pseudoparalysis but worse outcome and strength with longer duration pseudoparalysis

PURPOSE

The purpose of this study was to analyze whether unique SCR with key-hole technique using Achilles allograft can improve pseudoparalysis in patients with irreparable rotator cuff tears and additionally to identify preoperative factors that influence clinical outcomes.

METHODS

Between January 2018 and October 2021, patient data from SCR with our institution's unique key-hole technique using Achilles were retrospectively collected (minimum 2-years follow up). The patients were categorized into pseudoparalysis group (P group) and no pseudoparalysis group (NP group). Active range of motion (ROM) of shoulder, clinical scores (constant and pain visual analog scale scores) and muscle strength was assessed preoperatively and at 2-years postoperatively. And the correlation between preoperative and postoperative clinical data was analyzed through simple linear regression in the P group.

RESULTS

69 patients who underwent SCR with key-hole technique using Achilles, were included in the study. Group P and NP had 24 and 45 cases, respectively. Preoperative ROM (FE, ER), constant score and muscle strength (FE, ER) were significantly lower in P group than NP group. At 2-year follow-up the active ROM (FE, p<0.001, ER, p<0.001), constant score, VAS, muscle strength (FE, p<0.001, ER, p<0.001) were improved in the P group. In P group, pseudoparalysis recovered in 21 out of 24 patients (87.5%) at 2-year after surgery. The minimum clinically important difference of patient reported outcomes (Constant Score / VAS) were 8.15/1.05 for the P group and 9.47/0.92 for the NP group. Among the 3 cases of recovery failed, 2 cases were due to graft failure, and 1 case had delayed recovery. Prolonged preoperative pseudoparalysis and weaker preoperative external rotation strength were associated with worse clinical outcomes.

CONCLUSIONS

Superior capsular reconstruction with mini open key-hole technique using Achilles allograft demonstrates favorable outcomes for patients with preoperative pseudoparalysis. However, for SCR with the pseudoparalyis patients the careful attention is needed because the longer pseudoparalysis duration and the weaker external rotation strength could have the tendency of worse postoperative outcomes.

Can the Sterilization Protocol Be Improved to Enhance the Healing of Allograft Tendons? An In Vivo Study in Rabbit Tendons

BACKGROUND

Peracetic acid and irradiation are common sterilization methods for allograft tendons; however, under some conditions, both methods adversely affect the fiber arrangement and ultimate load of the tendon. An in vitro study showed that low-dose peracetic acid combined with irradiation may be less detrimental to allograft tendon structure and properties, possibly because the breakdown of peracetic acid can lead to an enlargement of the interstitial spaces and an increase in porosity.

QUESTIONS/PURPOSES

Using a rabbit Achilles tendon model, we asked: What is the effect of peracetic acid-ethanol combined irradiation on (1) the histopathology and fiber diameter of the allograft tendon, (2) tensile creep and load-to-failure biomechanical properties of allograft tendons, and (3) healing of the treated tendon in vivo compared with fresh-frozen allograft and peracetic acid-ethanol sterilization at 4 and 8 weeks?

METHODS

The Achilles tendons used in this study were sourced from euthanized 10-week-old male New Zealand White rabbits previously used for ophthalmic experiments. All allografts were divided into three groups: fresh-frozen group (control group, n = 20), peracetic acid-ethanol sterilization group (n =20), and peracetic acid-ethanol combined irradiation group (n = 20). The sterilization protocols were performed per a predetermined plan. In the peracetic acid-ethanol sterilization group, the tendon tissues were covered with the peracetic acid-ethanol sterilization solution (1% peracetic acid for 30 minutes). In the peracetic acid-ethanol combined irradiation group, the tendon tissues were covered with the peracetic acid-ethanol sterilization solution (0.2% peracetic acid for 30 minutes) and were subjected to 15 kGy gamma irradiation. Thirty 10-week-old male New Zealand White rabbits received bilateral Achilles tendon allografts surgically. Tendon samples from each group were harvested at 4 weeks (n = 30) and 8 weeks (n = 30) postoperatively. For each timepoint, eight tissues were used for histologic staining and electron microscopy, 15 tissues were used for biomechanical testing, and seven tissues were used for hydroxyproline assay and quantitative polymerase chain reaction. Histopathology was determined qualitatively by hematoxylin and eosin and Masson staining, while fiber diameter was measured quantitatively by transmission electron microscopy. Biomechanical properties were measured using cyclic loading tests and load-to-failure tests. The healing outcome was quantitatively judged through healing-related genes and proteins.

RESULTS

At 4 weeks and 8 weeks postoperatively, the peracetic acid-ethanol combined irradiation group visually demonstrated the best continuity and minimal peripheral adhesions. Histologic staining showed that tendon fibers in the peracetic acid-ethanol combined irradiation group maintained consistent alignment without notable disruptions or discontinuities, and there was a qualitatively observed increase in the number of infiltrating cells compared with the control group at the 4-week timepoint (444 ± 49 /mm 2 versus 256 ± 43 /mm 2 , mean difference 188 /mm 2 [95% confidence interval 96 to 281]; p < 0.001). At 8 weeks postoperatively, the tendon fiber diameter in the peracetic acid-ethanol combined irradiation groups was similar to that of the control group (0.23 ± 0.04 µm versus 0.21 ± 0.03 µm, mean difference 0.02 µm [95% CI -0.04 to 0.08]; p = 0.56). At 8 weeks postoperatively, the peracetic acid-ethanol combined irradiation group exhibited better properties in terms of both ultimate load (129 ± 15 N versus 89 ± 20 N, mean difference 40 N [95% CI 7 to 73]; p = 0.02) and energy absorption density (17 ± 6 kJ/m 2 versus 8 ± 4 kJ/m 2 , mean difference 8 kJ/m 2 [95% CI 0.7 to 16]; p = 0.004) compared with the control group. Gene expression analysis revealed higher expression levels of COL1A1 (2.1 ± 0.8 versus 1.0 ± 0, mean difference 1.1 [95% CI 0.1 to 2.1]; p = 0.003) and MMP13 (2.0 ± 0.8 versus 1.0 ± 0, mean difference 1.0 [95% CI 0.4 to 1.6]; p = 0.03) in the peracetic acid-ethanol combined irradiation group than in the control group. There was a higher amount of collagen Type I in tendons treated with peracetic acid-ethanol combined irradiation than in the control group (0.36 ± 0.03 versus 0.31 ± 0.04, mean difference 0.05 [95% CI 0.01 to 0.09]; p = 0.02).

CONCLUSION

Treatment with peracetic acid-ethanol combined irradiation did not have any discernible adverse effect on the histology, fiber diameter, enzymatic resistance, collagen content, or biomechanical strength of the allograft tendons compared with the control group. Peracetic acid-ethanol combined irradiation treatment had a positive impact on remodeling of the extracellular matrix and realignment of collagen fibers.

CLINICAL RELEVANCE

This sterilization method could be helpful to expand the scope and frequency with which allogeneic materials are applied. The long-term healing effect and strength of allograft tendons must be tested before clinical use, and it is necessary to conduct comparative studies on autografts and synthetic materials that are currently widely used clinically.

A biomechanical study to optimize superior capsular reconstruction operative technique

Background

The goals of this study were to optimize superior capsular reconstruction by assessing the relative fixation strength of 4 suture anchors; evaluating 3 glenoid neck locations for fixation strength and bone mineral density (BMD); determining if there is a correlation between BMD and fixation strength; and determining which portal sites have optimal access to the posterosuperior and anterosuperior glenoid neck for anchor placement.

Methods

Twenty cadaveric specimens were randomized into 4 groups: all-suture anchor (FiberTak), conventional 3.0-mm knotless suture anchor (SutureTak), 3.9-mm knotless PEEK (polyetheretherketone) Corkscrew anchor, and 4.5-mm Bio-Corkscrew anchor. Each specimen was prepared with 3 anchors into the glenoid: an anterosuperior anchor, superior anchor, and posterosuperior anchor. All anchors were inserted into the superior glenoid neck 5 mm from the glenoid rim. A materials testing system performed cyclic testing (250 cycles) followed by load-to-failure testing at 12.5 mm/s. Cyclic elongation, first cycle excursion, maximum load, and stiffness were recorded. Using custom software, BMD was calculated at each anchor location. This software was also used to assess access to the posterosuperior and anterosuperior glenoid neck from standard arthroscopic portal positions.

Results

There was no significant difference in cyclic elongation (P = .546), first cycle excursion (P = .476), maximum load (P = .817), or stiffness (P = .309) among glenoid anchor positions. Cyclic elongation was significantly longer in the PEEK Corkscrew group relative to the other implants (P ≤ .002). First cycle excursion was significantly greater in the FiberTak group relative to all other implants (P ≤ .008). For load-to-failure testing, the Bio-Corkscrew group achieved the highest maximum load (P ≤ .001). No other differences in cyclic or failure testing were observed between the groups. No differences in stiffness testing were observed (P = .133). The superior glenoid rim had the greatest BMD (P = .003), but there was no correlation between BMD and cyclic/load outcomes. The posterior portal (80% of specimens) and the anterior portal (60% of specimens) demonstrated the best access to the posterosuperior and anterosuperior glenoid neck, respectively.

Conclusion

The 4.5-mm Bio-Corkscrew anchor provided the most robust fixation to the glenoid during superior capsular reconstruction as it demonstrated the strongest maximum load, had minimal elongation, had minimal first cycle excursion, and did not fail during cyclic testing. The superior glenoid neck had the highest BMD; however, there was no correlation between BMD or glenoid anchor location and biomechanical outcomes. The posterior portal and anterior portal provided optimal access to the posterosuperior glenoid neck and anterosuperior glenoid neck, respectively.

Acellular Dermal Allograft and Tensor Fascia Lata Autograft Show Similar Patient Outcome Improvement and High Rates of Complications and Failures at a Minimum Two-Year Follow-up: A Systematic Review

PURPOSE

To compare clinical and radiologic outcomes following superior capsular reconstruction (SCR) using dermal allograft versus tensor fascia lata (TFL) autograft for massive rotator cuff tears with a minimum 2-year follow-up.

METHODS

A literature search was performed by querying Scopus, EMBASE, and PubMed computerized databases from database inception through September 2022 in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies evaluating clinical and radiologic outcomes, as well as complications following SCR for the treatment of massive rotator cuff tears were included. Study quality was assessed via the Newcastle-Ottawa Scale and the National Institutes of Health Quality Assessment. The mean change from preoperative to postoperative values (delta) was calculated for each outcome.

RESULTS

Seventeen studies, consisting of 519 patients were identified. Mean duration of follow-up ranged from 24 to 60 months. Mean reduction in visual analog scale pain score ranged from 2.9 to 5.9 points following use of dermal allograft, and 3.4 to 7.0 points following TFL autograft reconstruction. Mean improvements in American Shoulder and Elbow Surgeons score were similar between groups (dermal allograft: 28.0-61.6; TFL autograft: 24.7-59.3). The mean increase in forward flexion ranged from 31° to 38° with dermal allograft, versus 19° to 69° with TFL autograft. Average improvement in active external rotation with dermal allograft ranged from -0.4° to 11° and from 2° to 22.4° using TFL autograft. A similar change in acromiohumeral distance following SCR (dermal allograft: 0.9-3.2 mm; TFL autograft: 0.3-3.6 mm) was appreciated. The rate of complications within the dermal allograft group ranged from 4.5% to 38.2% versus 13.3% to 86.4% following TFL autograft. Failure rate ranged from 4.5 to 38.2% following dermal allograft versus 4.5 to 86.4% with TFL autograft.

CONCLUSIONS

Acellular dermal allograft versus TFL autograft for SCR both demonstrate improved VAS and American Shoulder and Elbow Surgeons scores, with increased values in flexion and external rotation, and increased visual analog scale, although with high variability. Both grafts demonstrate high rates of complications and failures at minimum 2-year follow-up.

LEVEL OF EVIDENCE

IV; systematic review of level II-IV studies.

Early Treatment of Shoulder Pathology Is Necessary but Not Enough Is Being Performed

Delayed treatment of shoulder instability results in bone loss requiring more-complicated surgery, in turn resulting in less-optimal outcomes. Similarly, delayed treatment of repairable rotator cuff tears results in irreparable tears requiring more-complicated surgery and resulting in less-optimal outcomes. Delayed treatment of shoulder pathology is a problem. Solutions include education and research investigation.