Supraspinatus Tendon Reconstruction Versus the Bridging Technique in a Rat Model: Histological, Biomechanical, and Functional Outcomes.

BACKGROUND: Massive irreparable rotator cuff tears (MIRCTs) are among the most challenging shoulder conditions to treat surgically. Supraspinatus tendon reconstruction (STR) is a recently introduced technique for MIRCTs based on fascia lata-muscle interface healing, which completely differs from the classic bridging technique with fascia lata-tendon interface healing. However, histological and biomechanical comparisons of the fascia-muscle and fascia-tendon interfaces have not been performed. PURPOSE: To investigate the histological and biomechanical healing of the fascia-bone interface and fascia-muscle interface after chronic MIRCTs in a rat model using different surgical methods. STUDY DESIGN: Controlled laboratory study. METHODS: The authors established a chronic MIRCT model in the right shoulder of rats and then repaired it using the STR or bridging repair technique. Evaluations were performed at 2, 4, 8, and 12 weeks, including histological, imaging, biomechanical, and functional analyses. RESULTS: Both techniques resulted in good fascia-bone interface healing based on the histological results. The STR group had significantly more cartilage formation at 8 and 12 weeks and higher Modified Tendon Maturity Score after 12 weeks at the fascia-bone interface compared with the bridging repair group and formed the typical 4-layered structure. Collagen fibers in the fascia-muscle and fascia-tendon interfaces exhibited normal muscle-tendon interface characteristics at 12 weeks. However, the STR group had more improvement in fatty infiltration compared with the bridging repair group. The ultimate failure load and stiffness did not differ between the STR and bridging repair groups 4 weeks postoperatively in both the fascia-bone interface and supraspinatus muscle-fascia-bone integrity. Movement distance and grasp time were significantly longer in the STR group than in the bridging repair group at 12 weeks and attached the level in the normal control groups. CONCLUSION: These results suggest that the fascia-muscle interface from the STR technique is histologically and functionally better than the fascia-tendon interface. Moreover, this study provides a theoretical basis for the clinical use of the STR technique. CLINICAL RELEVANCE: The fascia-muscle interface and fascia-tendon interface were the key points of the STR and bridging techniques, respectively. The fascia-muscle interface is histologically and functionally superior to the bridging technique, and the STR technique might be a better choice for the treatment of MIRCTs.

[Comparison of mid-term effectiveness between diabetic secondary stiff shoulder and primary frozen shoulder after arthroscopic shoulder capsular release combined with acromiohumeral distance restoration].

Objective: To compare the mid-term effectiveness of arthroscopic shoulder capsular release combined with acromiohumeral distance (AHD) restoration in the treatment of diabetic secondary stiff shoulder and primary frozen shoulder. Methods: A retrospective analysis was conducted on clinical data of 22 patients with diabetic secondary stiff shoulder (group A) and 33 patients with primary frozen shoulder (group B), who underwent arthroscopic 270° capsular release combined with AHD restoration treatment. There was no significant difference between the two groups in gender, age, affected side, disease duration, and preoperative AHD, shoulder flexion range of motion, abduction range of motion, American Shoulder and Elbow Surgeons (ASES) score, visual analogue scale (VAS) score, and Constant score ( P>0.05). Only the difference in the internal rotation cone rank and external rotation range of motion between the two groups showed significant differences ( P<0.05). The improvement in shoulder pain and function was evaluated by using VAS score, ASES score, and Constant score before operation and at last follow-up. Active flexion, abduction, external rotation range of motion, and internal rotation cone rank were recorded and compared. AHD was measured on X-ray films. Results: All patients were followed up 24-92 months (median, 57 months). There was no significant difference in follow-up time between group A and group B ( P>0.05). No fractures or glenoid labrum tears occurred during operation, all incisions healed by first intention, and no complication such as wound infection or nerve injury was observed during the follow-up. At last follow-up, there were significant improvements in active flexion, abduction, external rotation range of motion, internal rotation cone rank, AHD, VAS score, ASES score, and Constant score when compared with preoperative ones in both groups ( P<0.05). Except for the difference in change in external rotation range of motion, which had significant difference between the two groups ( P<0.05), there was no significant difference in other indicators between the two groups ( P>0.05). Conclusion: Arthroscopic capsular release combined with AHD restoration can achieve good mid-term effectiveness in the treatment of diabetic secondary stiff shoulder and primary frozen shoulder. However, the improvement in external rotation range of motion is more significant in the patients with diabetic secondary stiff shoulder.

Fascia Lata Autografts Achieve Interface Healing With the Supraspinatus Muscle Histologically and Mechanically in a Rat Supraspinatus Tendon Reconstruction Model for Massive Irreparable Rotator Cuff Tears.

PURPOSE: To evaluate the histologic healing process and mechanical characteristics of the interface between a fascia lata autograft and supraspinatus muscle by establishing a supraspinatus tendon reconstruction model for chronic massive irreparable rotator cuff tears (MIRCTs). METHODS: A total of 40 rats were studied. Eight rats were killed to establish an intact control group, and the other rats were first established as a chronic MIRCT model and then developed as the supraspinatus tendon reconstruction model. Histology, fatty infiltration, mechanics, and open field test for the interface between the fascia lata autograft and muscle were assessed at 2, 4, 8, and 16 weeks postoperatively. RESULTS: Histologically, the interface between the fascia lata autograft and muscle gradually regenerated structural characteristics similar to the normal muscle-tendon interface by 16 weeks postoperatively. The amount of collagen I and III increased significantly during the healing time and stabilized at 8 weeks postoperatively. Fatty infiltration was obvious in the supraspinatus muscle 4 weeks after establishing the MIRCT model. However, the degree of fatty infiltration in the supraspinatus muscle gradually decreased after supraspinatus tendon reconstruction and stabilized at 8 weeks postoperatively. The ultimate failure force and ultimate stress gradually increased from 2 to 16 weeks and reached the level of the intact control tendon at 16 weeks postoperatively (P = .086). The movability of the forepaw returned to normal in the open field test (P = .907). CONCLUSIONS: In this rat supraspinatus tendon reconstruction model, fascia lata autografts showed good interface healing with the supraspinatus muscle, and fatty infiltration in the supraspinatus muscle was histologically decreased. The interface between the fascia lata autograft and muscle showed mechanical strength similar to the anatomic muscle-tendon interface. CLINICAL RELEVANCE: A supraspinatus tendon reconstruction technique using fascia lata autografts might be a good histologic and biomechanical option for treating MIRCTs.

Supraspinatus Tendon Reconstruction Using Fascia Lata Autograft for Irreparable Posterosuperior Massive Rotator Cuff Tears.

Superior capsule reconstruction has shown good long-term clinical efficacy in treating irreparable posterosuperior massive rotator cuff tears. However, conventional superior capsule reconstruction did not treat the medial supraspinatus tendons. Therefore, dynamic function of the posterosuperior rotator cuff does not restore effectively, especially the function of active abduction and external rotation. We describe a supraspinatus tendon reconstruction technique that presents a stepwise approach to accomplish the dual goals of stable anatomic reconstruction and restoring the dynamic function of the supraspinatus tendon.

Dynamic Superior Capsular Reconstruction for Irreparable Massive Rotator Cuff Tears: Histologic Analysis in a Rat Model and Short-term Clinical Evaluation.

BACKGROUND: Superior capsular reconstruction (SCR) has been demonstrated to be a valuable treatment for patients with irreparable massive rotator cuff tears (IMRCTs). However, the torn medial supraspinatus (SSP) tendons, which acted as dynamic stabilizers, were left untreated in conventional SCR, and the dynamic force from the SSP tendon was not restored. PURPOSE: To evaluate the effect of dynamic SCR (dSCR) on fascia-to-bone healing in a rat model, and to compare the short-term clinical effectiveness of dSCR and SCR using autologous fascia lata (FL) in patients with IMRCTs. STUDY DESIGN: Controlled laboratory study and cohort study; Level of evidence, 3. METHODS: A total of 50 rats were divided randomly into 2 groups: the dSCR group and the SCR group (25 rats per group). First, chronic IMRCTs were created, and then the torn tendons in both groups were subjected to SCR using autologous thoracolumbar fascial (TLF) grafts. The remnant of the SSP tendon was sutured to the medial part of the TLF graft in the dSCR group but not in the SCR group. Histologic sections were assessed at 1, 2, 4, 8, and 16 weeks postoperatively. In the clinical study, 22 patients (9 SCR, 13 dSCR) were analyzed. The recovery of shoulder function, including the active range of motion (ROM), visual analog scale (VAS), American Shoulder and Elbow Surgeons score, Constant score, and University of California Los Angeles score, acromiohumeral distance (AHD), and fatty infiltration, was evaluated before surgery and at the last follow-up. RESULTS: Histologic analysis of the fascia-to-bone junction in the rat model showed that the TLF gradually migrated into tendon-like tissue over the rotator cuff defects in both groups, and the modified tendon maturation score of the fascia-to-bone interface in the dSCR group was higher than that in the SCR group at 4 weeks (12.20 ± 1.30 vs 14.60 ± 1.52; P = .004), 8 weeks (19.60 ± 1.14 vs 22.20 ± 1.10; P = .019), and 16 weeks (23.80 ± 0.84 vs 26.20 ± 0.84 P = .024). The dSCR group showed earlier fibrocartilage cell formation and angiogenesis. In the clinical study, all 22 patients completed a minimum of 12 months of follow-up after surgery, and the mean follow-up duration was 22.89 ± 7.59 months in the SCR group and 25.62 ± 7.32 months in the dSCR group. The patients in both groups showed significant improvements in terms of ROM, shoulder function scores, and AHD. At the last follow-up, abduction (56.67°± 27.39° vs 86.54°± 30.37°; P = .029), external rotation (25.00°± 9.35° vs 33.08°± 8.55°; P = .049), internal rotation cone rank (-2.78 ± 2.44 vs -4.38 ± 1.12; P = .049), VAS (-3.00 ± 0.87 vs -3.92 ± 0.95; P = .031) and Constant (47.89 ± 15.39 vs 59.15 ± 9.74; P = .048) scores, and the AHD improvement degree (3.06 ± 1.41 mm vs 4.38 ± 1.35 mm; P = .039) in the dSCR group were significantly improved compared with those in the SCR group. The results of fatty infiltration at the last follow-up showed that there was significant improvement compared with the preoperative results in both the conventional SCR (P = .036) and the dSCR (P = .001) groups. However, there were no significant differences between the 2 groups (P = .511). CONCLUSION: dSCR can promote faster fascia-to-bone healing in a rat model, and the dSCR technique could provide a preferable treatment option for patients with IMRCTs. CLINICAL RELEVANCE: dSCR might restore the dynamic of SSP in some sense and then improve the fatty infiltration in the SSP.

Revascularization character of autologous fascia lata graft following shoulder superior capsule reconstruction by enhanced magnetic resonance imaging.

BACKGROUND: Fascia lata has been used for arthroscopic superior capsule reconstruction (ASCR) and verified to achieve a good clinical outcome. However, it is still not known about revascularization character of the fascia lata after ASCR. This study was performed to evaluate the revascularization of autologous fascia lata grafts after ASCR by enhanced magnetic resonance imaging (MRI). METHODS: A prospective study of 19 patients with irreparable rotator cuff tears underwent ASCR with autologous fascia lata grafts from September 2019 to April 2021. Radiography examinations and clinical evaluations were performed preoperatively and postoperatively at 6 weeks and 3, 6, and 12 months. The signal-to-noise quotient (SNQ) value and enhancement index (EI) of autologous fascia lata grafts in the great tubercle insertion (GTI), midpoint of the graft (MG), and glenoid insertion (GI) were compared for radiography examination. Clinical evaluation included the American Shoulder and Elbow Surgeons (ASES) score, University of California Los Angeles (UCLA) shoulder score, and Visual Analog Scale (VAS) score. RESULTS: The SNQ values in T1WI enhancement at GI and GTI were significantly higher than those at the plain MRI scan at all postoperative observation timepoints; however, the SNQ values in T1WI enhancement at MG did not show a significant difference until 3 months postoperation. EI values at GTI and GI were significantly higher than those at MG at 6 weeks and 3 months postoperation, while there was no significant difference in the EI value between GTI and GI. At 6 months postoperation, the EI value at GI was significantly higher than those at MG. At 12 months postoperation, the EI value at GI was significantly higher than those at MG and GTI; however, there was no significant difference between GTI and MG. The EI values at GTI and MG peaked at 3 months and 6 months postoperation, respectively, and then plateaued at 12 months postoperation. However, there was no significant difference in the EI value among the different postoperative timepoints at GI. The EI value did not correlate with the VAS and ASES, UCLA scores at any time point or any postoperative observation location. CONCLUSION: Revascularization of the fascia lata was dependent on the location of the fascia lata and plateaus at 12 months postoperation. The EI value did not correlate with the VAS and ASES, UCLA scores during12 months postoperation.

Histologic and biomechanical evaluation of the thoracolumbar fascia graft for massive rotator cuff tears in a rat model.

BACKGROUND: Fascial autografts, which are easily available grafts, have provided a promising option in patients with massive rotator cuff tears. However, no fascial autografts other than the fascia lata have been reported, and the exact healing process of the fascia-to-bone interface is not well understood. The objective of this study is to histologically and biomechanically evaluate the effect of the thoracolumbar fascia (TLF) on fascia-to-bone healing. METHODS: A total of 88 rats were used in this study. Eight rats were killed at the beginning to form an intact control group, and the other rats were divided randomly into 2 groups (40 rats per group): the TLF augmentation group (TLF group) and the repair group (R group). The right supraspinatus was detached, and a 3 × 5 mm defect of the supraspinatus was created. The TLF was used to augment the torn supraspinatus in the TLF group, whereas in the R group, the torn supraspinatus was repaired in only a transosseous manner. Histology and biomechanics were assessed at 1, 2, 4, 8, and 16 weeks postoperatively. RESULTS: The modified tendon maturation score of the TLF group was higher than that of the R group at 8 weeks (23.00 ± 0.71 vs. 24.40 ± 0.89, P = .025) and 16 weeks (24.60 ± 0.55 vs. 26.40 ± 0.55, P ≤ .001). The TLF group showed a rapid vascular reaction, and the peak value appeared at 1 week. Later, the capillary density decreased, and almost no angiogenesis was observed at 8 weeks postoperatively. Immunohistochemistry results demonstrated a significantly higher percentage of collagen I in the TLF group at 4, 8, and 16 weeks (24.78% ± 2.76% vs. 20.67% ± 2.11% at 4 weeks, P = .046; 25.46% ± 1.77% vs. 21.49% ± 2.33% at 8 weeks, P = .026; 34.77% ± 2.25% vs. 30.01% ± 3.17% at 16 weeks, P = .040) postoperatively. Biomechanical tests revealed that the ultimate failure force in the TLF group was significantly higher than that in the R group at the final evaluation (29.13 ± 2.49 N vs. 23.10 ± 3.47 N, P = .022). CONCLUSIONS: The TLF autograft can promote a faster biological healing process and a better fixation strength. It could be used as an alternative reinforcement or bridging patch when the fascia lata is not appropriate or available for superior capsule reconstruction (SCR).

[The short-term effectiveness of superior capsular reconstruction using autologous fascia lata graft for irreparable massive rotator cuff tears].

OBJECTIVE: To observe and evaluate the short-term effectiveness of superior capsular reconstruction using autologous fascia lata graft for irreparable massive rotator cuff tears. METHODS: The clinical data of 9 patients with irreparable massive rotator cuff tears treated with arthroscopic superior capsular reconstruction by using autologous fascia lata graft between September 2019 and April 2020 were retrospectively analysed. There were 4 males and 5 females with a median age of 66 years (range, 55-70 years). The disease duration was 6-60 months with an average of 19.1 months. According to Hamada classification, the patients were classified as grade 1 in 2 cases, grade 2 in 2 cases, grade 3 in 2 cases, and grade 4 in 3 cases. Before and after operation, the visual analogue scale (VAS) score was used to evaluate the improvement of shoulder joint pain, the American Shoulder and Elbow Surgeons (ASES) score, Constant score, and the University of California Los Angeles (UCLA) shoulder function score were used to evaluate the improvement of shoulder joint function. The active range of motion of shoulder joint was recorded, including forward flexion, abduction, lateral external rotation, and internal rotation. The changes of subacromial space were recorded by anteroposterior X-ray film of shoulder joint. Sugaya classification was used to judge the integrity of rotator cuff immediately after operation and at last follow-up. RESULTS: The operation time was 210-380 minutes, with an average of 302.3 minutes. All incisions healed by first intention after operation, and there was no complication such as infection and nonunion of incisions. Two patients had numbness of the upper limbs on the surgical side after operation, and the numbness completely relieved at 6 weeks after operation; 5 cases with preoperative pseudoparalysis symptoms recovered after operation. Nine patients were followed up 12-17 months, with an average of 14.1 months. At last follow-up, the patient's active range of motion of shoulder joint (forward flexion, abduction, lateral external rotation, and internal rotation), subacromial space distance, VAS score, ASES score, Constant score, and UCLA score significantly improved when compared with preoperative ones ( P<0.05). There was no significant difference in the Sugaya classification between at last follow-up and immediately after operation ( Z=-1.633, P=0.102). CONCLUSION: Superior capsular reconstruction using autologous fascia lata graft can restore the superior stability and achieve a good short-term effectiveness for irreparable massive rotator cuff tears.

Advancement in Arthroscopic Superior Capsular Reconstruction for Irreparable Massive Rotator Cuff Tear.

Irreparable massive rotator cuff tear (IMRCT) was one of the causes of shoulder dysfunction, despite technical improvement, the failure rate of IMRCT was still demonstrated to be high. Traditional treatments like non-surgical treatments, partial rotator cuff repair, and tendon transfers could only achieve a slight improvement. A potential cause for high failure rate was the fact that traditional treatments cannot restore the superior stability of glenohumeral joint, and thus restricted the movement of shoulder joint severely. Superior capsular reconstruction (SCR) using a variety of grafts (autograft, allograft, xenograft, or synthetic grafts) provided a promising option for IMRCT. In surgery, graft was fixed medially to superior glenoid and laterally to the footprint of humeral greater tuberosity. SCR could increase the stability of the superior glenohumeral joint, decrease the subacromial pressure and acromiohumeral distance. This review summarized the relevant literature regarding the alternative grafts, surgery indications, operative techniques and clinical outcomes of SCR. we compared the different grafts, key surgical steps, the advantages and disadvantages of different surgical methods to provide clinicians with new surgical insights into the treatments of IMRCT. In conclusion, IMRCT without severe glenohumeral arthritis was the best suitable indication for SCR. The clinical outcomes were positive in the short-term and middle-term following-up. More studies were necessary to determine long-term results of this surgical procedure.

Femtosecond laser-induced periodic grooves and nanopore clusters make a synergistic effect on osteogenic differentiation.

Polyether-ether-ketone (PEEK) materials have good biocompatibility, excellent corrosion resistance, chemical stability and an elastic modulus close to that of natural bone. However, due to its biological inertness, PEEK may affect osteogenic differentiation and leads to osseointegration failure, though PEEK is expected to improve osseointegration. In this work, by changing the power of femtosecond laser, micro-grooves are made on the PEEK surface. As observed by scanning electron microscopy, the trench has a periodic structure, the micro shape is neat, and the trench is also covered with nanometer-level pore clusters. In the in vitro culture experiments, through the proliferation experiment of mouse bone marrow mesenchymalstem cells (mBMSCs), cell viability analysis and alkaline phosphatase activity analysis, it is proven that after femtosecond laser treatment of the PEEK surface, the micro-grooves on the surface and the nanopore clusters due to laser energy ablation can produce a synergistic effect, enhancing the osteogenic differentiation ability of cells, and improving the bone integration ability of PEEK materials.

[Research progress of indication and treatment of graft in shoulder superior capsular reconstruction for rotator cuff tear].

OBJECTIVE: To review the research progress of indication and treatment of graft in shoulder superior capsular reconstruction (SCR) for rotator cuff tear (RCT). METHODS: The literature related to shoulder SCR in recent years was extensively reviewed, and the anatomy, biomechanics, surgical indications, and treatment of graft in SCR were summarized. RESULTS: Superior capsule plays a role as a functional complex with rotator cuff, ligament, and whole capsule. SCR can effectively restore the superior stability of the shoulder. The indications of SCR include the irreparable massive RCT, massive RCT combined with pseudoparalysis shoulder, medium/large RCT with severe degenerative rotator cuff tissue, and dual-layer RCT. In order to achieve a better healing of tendon-bone in graft and decrease the rate of long-term graft retearing, it is essential to select an appropriate thickness graft, fix the graft in right intensity, and get a better capsular continuity. CONCLUSION: The technique of SCR advanced to SCR for reinforcement and it is indicated from substantial massive RCT to severe degeneration of rotator cuff tissue. Graft treatment is the key step for a successful SCR.

[Three-dimensional printed Ti6Al4V-4Cu alloy promotes osteogenic gene expression through bone immune regulation].

OBJECTIVE: To investigate the effects of three-dimensional (3D) printed Ti6Al4V-4Cu alloy on inflammation and osteogenic gene expression in mouse bone marrow mesenchymal stem cells (BMSCs) and mouse mononuclear macrophage line RAW264.7. METHODS: Ti6Al4V and Ti6Al4V-4Cu alloys were prepared by selective laser melting, and the extracts of the two materials were prepared according to the biological evaluation standard of medical devices. The effects of two kinds of extracts on the proliferation of mouse BMSCs and mouse RAW264.7 cells were detected by cell counting kit 8 method. After co-cultured with mouse BMSCs for 3 days, the expression of osteogenesis- related genes [collagen type Ⅰ (Col-Ⅰ), alkaline phosphatase (ALP), Runx family transcription factor 2 (Runx-2), osteoprotegerin (OPG), and osteopontin (OPN)] were detected by real-time fluorescence quantitative PCR. After co-cultured with mouse RAW264.7 cells for 1 day, the expressions of inflammation-related genes [interleukin 4 (IL-4) and nitric oxide synthase 2 (iNOS)] were detected by real-time fluorescence quantitative PCR, and the supernatants of the two groups were collected to detect the secretion of vascular endothelial growth factor a (VEGF-a) and bone morphogenetic protein 2 (BMP-2) by ELISA. The osteogenic conditioned medium were prepared with the supernatants of the two groups and co-cultured with BMSCs for 3 days. The expressions of osteogenesis-related genes (Col-Ⅰ, ALP, Runx-2, OPG, and OPN) were detected by real-time fluorescence quantitative PCR. RESULTS: Compared with Ti6Al4V alloy extract, Ti6Al4V-4Cu alloy extract had no obvious effect on the proliferation of BMSCs and RAW264.7 cells, but it could promote the expression of OPG mRNA in BMSCs, reduce the expression of iNOS mRNA in RAW264.7 cells, and promote the expression of IL-4 mRNA. It could also promote the secretions of VEGF-a and BMP-2 in RAW264.7 cells. Ti6Al4V-4Cu osteogenic conditioned medium could promote the expressions of Col-Ⅰ, ALP, Runx-2, OPG, and OPN mRNAs in BMSCs. The differences were all significant ( P<0.05). CONCLUSION: 3D printed Ti6Al4V-4Cu alloy can promote RAW264.7 cells to secret VEGF-a and BMP-2 by releasing copper ions, thus promoting osteogenesis through bone immune regulation, which lays a theoretical foundation for the application of metal prosthesis.