Tendon-healing to cortical bone compared with healing to a cancellous trough. A biomechanical and histological evaluation in goats

Efficacy of an Autologous Dermal Fibroblast Injection in Reducing the Retear Rate After Arthroscopic Rotator Cuff Repair: A Prospective Randomized Controlled Trial

BACKGROUND

Interest in biological augmentation for improving bone-tendon interface (BTI) healing after arthroscopic rotator cuff repair (ARCR) is growing. Dermal fibroblasts, known for collagen synthesis similar to tenocytes, have shown effectiveness in BTI healing in chronic rotator cuff tear (RCT) models in rabbits. However, no human clinical trials have been conducted.

PURPOSE

To evaluate the clinical efficacy of autologous dermal fibroblasts (ADFs) for BTI healing after ARCR in patients with full-thickness RCTs >2 cm.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

A total of 86 patients were prospectively enrolled and randomized into 2 groups: an additional ADF injection between the bone and tendon during ARCR (ADF group) or ARCR alone (control group). A skin biopsy from the buttock was performed to obtain ADFs, which were cultured for approximately 4 weeks before surgery. ARCR was standardized to the double-row suture bridge technique to reduce the heterogeneity in different repair methods. The primary variable for evaluating ADF efficacy was the retear rate using magnetic resonance imaging at 6 months postoperatively. Secondary variables included range of motion, the American Shoulder and Elbow Surgeons score, the Constant score, and the Simple Shoulder Test score at baseline and at 6 and 12 months postoperatively.

RESULTS

Overall, 13 patients dropped out because of a subscapularis tendon tear, loss to follow-up, or the withdrawal of consent (7 in the ADF group and 6 in the control group). The retear rate was significantly lower in the ADF group (5.6% [2/36]) than in the control group (24.3% [9/37]) (P = .025). The American Shoulder and Elbow Surgeons, Constant, and Simple Shoulder Test scores showed significant improvement after surgery in both groups (all P values <.001). Functional scores and range of motion did not significantly differ between the 2 groups at 6 and 12 months (all P values >.05).

CONCLUSION

ADF application into the BTI during ARCR significantly decreased the retear rate in patients with full-thickness RCTs >2 cm. Therefore, an ADF injection could be a promising biological supplement to enhance BTI healing in these patients. However, clinical outcomes showed no significant difference between the 2 groups at 6 months and 1 year postoperatively.

Bone Marrow Stimulation Yielded Similar Clinical Outcomes With Improved Tendon Healing and Abduction Strength Compared With Decortication for Arthroscopic Rotator Cuff Repair in Shoulder Active Patients

PURPOSE

To compare the clinical outcomes and tendon healing between bone marrow stimulation (BMS) and decortication as footprint preparation techniques for arthroscopic rotator cuff repair (ARCR) in shoulder active patients.

METHODS

This double-blinded randomized clinical trial recruited 120 patients aged older than 45 years, at active levels, and diagnosed with chronic unilateral rotator cuff tears. Participants were 1:1 randomized to undergo ARCR using the double-row suture-bridge technique with BMS (BMS group) or with decortication (DEC group) for footprint preparation. The primary outcome was the American Shoulder and Elbow Surgeons score (range, 0-100, with greater scores indicating better shoulder function and fewer symptoms) at 24 months. Secondary outcomes included patient-reported outcomes, physical examinations, and rotator cuff integrity (evaluated on magnetic resonance imaging using a 5-graded system).

RESULTS

Of the 120 participants (age, 58.7 ± 8.1 years; 83 females [69.2%]) enrolled and randomized between May 2017 and November 2021, 109 (90.8%) were analyzed with the completion of follow-up visits. The American Shoulder and Elbow Surgeons scores at 24 months were not statistically significantly different between the BMS and DEC groups (89.2 ± 12.2 vs 87.8 ± 13.9; adjusted difference, 1.7; 95% confidence interval -3.3 to 6.7; P = .498). The BMS group showed superior rotator cuff integrity (incomplete healing, 33.9% vs 54.7%; P = .029) and abduction muscle strength (8.7 ± 3.2 vs 7.4 ± 3.3 kg; P = .031) at 24 months as compared with the DEC group; the superiority was more significant in the subgroup of participants with higher shoulder activity levels. The rates of adverse events were comparable between groups.

CONCLUSIONS

Among shoulder active patients undergoing ARCR, BMS did not result in superior patient-reported outcomes at 24 months postoperatively compared with decortication. Nevertheless, BMS resulted in greater rates of tendon healing and clinically significant improvement in abduction strength and thus can be recommended in patients requiring high levels of manual labor or sports activities.

LEVEL OF EVIDENCE

Level I, randomized clinical trial.

Fixation strength of swelling copolymeric anchors in artificial bone

Fixation with suture anchors and metallic hardware for osteosynthesis is common in orthopedic surgeries. Most metallic commercial bone anchors achieve their fixation to bone through shear of the bone located between the threads. They have several deficiencies, including stress-shielding due to mechanical properties mismatch, generation of acidic by-products, poor osteointegration, low mechanical strength and catastrophic failure often associated with large bone defects that may be difficult to repair. To overcome these deficiencies, a swelling porous copolymeric material, to be used as bone anchors with osteointegration potential, was introduced. The purpose of this study was to investigate the fixation strength of these porous, swelling copolymeric bone anchors in artificial bone of various densities. The pull-out and subsidence studies indicate an effective fixation mechanism based on friction including re-fixation capabilities, and minimization of damage following complete failure. The study suggests that this swelling porous structure may provide an effective alternative to conventional bone anchors, particularly in low-density bone.

When is a Reverse Shoulder Arthroplasty Indicated for a Rotator Cuff Tear?

Rotator cuff tears are the most frequent shoulder injury in patients over 50 years old. Treatment of rotator cuff tears is individualized based on the age, demands, and symptoms of the patient. Nonoperative treatment may often be effective, especially in lower-demand or elderly patients. Surgical repair is indicated after failure of nonoperative treatment or in patients whose high-demand lifestyle requires full strength and function of the shoulder. In older patients, larger tears are less likely to heal and rotator cuff repair may not reliable. In cases of failed previous rotator cuff repair, there may not be enough viable tissue for complete repair. If there is underlying arthritis, a rotator cuff repair is unlikely to resolve all symptoms, and treatment to care for the arthritis and rotator cuff tear is indicated. Reverse shoulder arthroplasty provides the surgical answer for these scenarios and is now being used for numerous indications of shoulder pathology.

A porous swelling copolymeric material for improved implant fixation to bone

Most metallic commercial bone anchors, such as screws and suture anchors achieve their fixation to bone through shear of the bone located between the threads. They have several deficiencies, potentially leading to failure, which are particularly evident in low-density bone. These include stress-shielding resulting from mechanical properties mismatch; lack of mechanically induced remodeling and osteointegration; and when the pullout force on the anchor, during functional activities, exceeds their pullout strength, catastrophic failure occurs leaving behind large bone defects that may be hard to repair. To overcome these deficiencies, we introduced in this study a porous swelling co-polymeric material and studied its swelling and compressive mechanical characteristics as bone anchor under different configurations. Porosity was achieved by adding a non-dissolvable agent (NaCl) during the process of polymerization, which was later dissolved in water, leaving behind a porous structure with adequate porosity for osteointegration. Three different groups of cylindrical samples of the swelling co-polymer were investigated. Solid, fully porous, and partially porous with a solid core and a porous outer layer. The results of the swelling and simple compression study show that the partially porous swelling co-polymer maintains excellent mechanical properties matching those of cancellous bone, quick swelling response, and an adequate porous outer layer for mechanically induced osteointegration. These suggest that this material may present an effective alternative to conventional bone anchors particularly in low-density bone.

Comparison of cortical versus cancellous bone fixation in tendon-to-bone healing with a rat trans-calcaneal suture model for Achilles tendon sleeve avulsion

BACKGROUND

Trans-calcaneal suture technique is an economical and effective method for repairing Achilles tendon sleeve avulsion. Whether cancellous bone fixation upon this technique could accelerate tendon-to-bone healing is unknown. The purpose of this study is to compare the effect of cortical versus cancellous bone fixation on tendon-bone healing with a novel rat trans-calcaneal suture model.

METHODS

Trans-calcaneal suture treatment was carried out on the right hindlimb in male Sprague-Dawley rats (N = 80). They were randomly divided into the cortical group (Achilles fixed to the calcaneal cortical bone, n = 40) and the cancellous group (Achilles fixed to the calcaneal cancellous bone, n = 40). Gait analysis and immunohistochemistry were performed 1, 4, 7, and 14 days after the operation. Gross observation, biomechanical analysis, micro-CT, and histological analysis were performed 4 and 8 weeks after surgery. Independent-samples t tests were used for comparison between groups.

RESULTS

At 1, 4, and 7 days, the swing time of the affected limb in the cancellous group decreased, while the duty cycle, the maximum contact area, the print area, and the mean intensity increased significantly. The cross-sectional area of the tendon-bone junction in the cancellous group was smaller, and the failure load and stiffness were higher 4 weeks after the operation. The cancellous group showed more proportion of new bone and a relatively well-organized and dense connective tissue interface with better fibrocartilage-like tissue at 4 weeks after the operation. The ratio of ED2 + macrophages in the cancellous group was significantly higher than in the cortical group on 1, 4, 7, and 14 days. There were no significant differences in gait at 2 weeks, in appearance, biomechanics, new bone formation, and histology at 8 weeks after surgery between the two groups.

CONCLUSION

In the new rat trans-calcaneal suture model, cancellous fixation can accelerate tendon-to-bone healing in the early stage, which perhaps is related to the abundant bone marrow tissue in the cancellous bone that modulates the inflammatory processes.

Allogeneic Dermal Fibroblasts Improve Tendon-to-Bone Healing in a Rabbit Model of Chronic Rotator Cuff Tear Compared With Platelet-Rich Plasma

PURPOSE

To compare the effects of allogeneic dermal fibroblasts (ADFs) and platelet-rich plasma (PRP) on tendon-to-bone healing in a rabbit model of chronic rotator cuff tear.

METHODS

Thirty-two rabbits were divided into 4 groups (8 per group). In 2 groups, the supraspinatus tendon was detached and was left as such for 6 weeks. At 6 weeks after creating the tear model, we performed transosseous repair with 5 × 10⁶ ADFs plus fibrin injection in the left shoulder and PRP plus fibrin in the right shoulder. The relative expression of the COL1, COL3, BMP2, SCX, SOX9, and ACAN genes was assessed at 4 weeks (group A) and 12 weeks (group B) after repair. Histologic and biomechanical evaluations of tendon-to-bone healing at 12 weeks were performed with ADF injection in both shoulders in group C and PRP injection in group D.

RESULTS

At 4 weeks, COL1 and BMP2 messenger RNA expression was higher in ADF-injected shoulders (1.6 ± 0.8 and 1.0 ± 0.3, respectively) than in PRP-injected shoulders (1.0 ± 0.3 and 0.6 ± 0.3, respectively) (P = .019 and P = .013, respectively); there were no differences in all genes in ADF- and PRP-injected shoulders at 12 weeks (P > .05). Collagen continuity, orientation, and maturation of the tendon-to-bone interface were better in group C than in group D (P = .024, P = .012, and P = .013, respectively) at 12 weeks, and mean load to failure was 37.4 ± 6.2 N/kg and 24.4 ± 5.2 N/kg in group C and group D, respectively (P = .015).

CONCLUSIONS

ADFs caused higher COL1 and BMP2 expression than PRP at 4 weeks and showed better histologic and biomechanical findings at 12 weeks after rotator cuff repair of the rabbit model. ADFs enhanced healing better than PRP in the rabbit model.

CLINICAL RELEVANCE

This study could serve as a transitional study to show the effectiveness of ADFs in achieving tendon-to-bone healing after repair of chronic rotator cuff tears in humans.

Smaller Gap Formation With Suture Anchor Fixation Than Traditional Transpatellar Sutures in Patella and Quadriceps Tendon Rupture: A Systematic Review

PURPOSE

The purpose of this study is to compare the biomechanical properties between traditional transosseous tunnel and suture anchor technique repair for extensor mechanism ruptures and assess for differences in the mechanism of failure of both techniques.

METHODS

A multi-database search (PubMed, EMBASE, and Medline) was performed according to PRISMA guidelines on November 14, 2021. All articles comparing biomechanical properties of transpatellar and suture anchor technique for extensor mechanism ruptures were included. Abstracts, reviews, case reports, studies without biomechanical analysis, conference proceedings, and non-English language studies were excluded. Outcomes pursued included gap formation, load to failure, and mechanism of failure. Relevant data from studies meeting inclusion criteria were extracted and analyzed. Study methodology was assessed using the Methodological Index for Non-Randomized Studies score.

RESULTS

A total of 212 knees were biomechanically assessed, including 98 patella and 114 quadricep tendon ruptures. Five patellar tendon studies were included, and all of them reported significantly smaller gap formation in suture anchor group. Gap formation for suture anchors ranged from .9 mm to 4.1 mm, while that of transpatellar group ranged from 2.9 mm to 10.3 mm. One study reported a significantly higher load to failure in the suture anchor group, while the remaining four studies reported no significant difference. Load to failure for suture anchor ranged from 259 N to 779 N, while that of the transpatellar group ranged from 287 N to 763 N. The most common mechanism of failure was anchor pullout in suture anchor and knot failure in the transpatellar group. Five quadriceps tendon studies were included, and three studies reported statistically significant smaller gap formation in the suture anchor group. Gap formation for suture anchor ranged from 1.5 mm to 5.0 mm, while that of transpatellar group ranged from 3.1 mm to 33.3 mm. Two studies reported a significantly higher load to failure in the suture anchor group, while one study reported a higher load to failure in the transpatellar repair group. Load to failure for suture anchor ranged from 286 N to 740 N, while that of transpatellar group ranged from 251 N to 691 N. The most common mechanism of failure was suture failure in the suture anchor and knot failure in the transpatellar group.

CONCLUSION

Suture anchor fixation displays a better biomechanical profile than traditional transpatellar techniques in terms of smaller gap formations in the repair of both patella and quadriceps tendon injuries. Anchor pullout in suture anchor fixation was present mainly with the use of titanium anchors.

CLINICAL RELEVANCE

These findings above may result in better retention of tendon approximation in patella and quadriceps tendon fixation postoperatively, which may result in earlier recovery. Further randomized controlled clinical trials to compare these techniques are required.

Revisional triangular fibrocartilage complex (TFCC) repair using arthroscopic one-tunnel transosseous suture: preliminary results

PURPOSE

The purpose of this study was to report the clinical outcome of revision arthroscopic triangular fibrocartilage complex (TFCC) foveal repair using a one-tunnel transosseous suture technique after failed primary TFCC repair.

METHODS

Consecutive patients treated with arthroscopic TFCC foveal repair using the uniform one-tunnel transosseous suture technique after failed TFCC repair from 2014 to 2018 were retrospectively reviewed. The clinical outcome was evaluated using the Modified Mayo Wrist Score (MMWS) and the Quick Disabilities of the Arm, Shoulder, and Hand (Quick-DASH) score. The Visual Analog Scale (VAS) for pain, stability of the distal radioulnar joint (DRUJ), grip strength, and active range of motion (ROM) of the wrist joint also were assessed.

RESULTS

This study cohort consisted of eight patients, and their mean time to revision after initial surgery was 15.1 months. Previous surgeries were performed using an arthroscopy-assisted mini-open TFCC repair in six cases, an arthroscopic all-inside repair in one case, and an arthroscopic transosseous suture technique in the remaining case. After revisional TFCC foveal repair, all patients demonstrated improved pain and a stable DRUJ. Participants showed improvement in grip strength and mean active wrist ROM. There was improvement in MMWS (from 58.6 to 87.5) and Quick-DASH score (from 46.9 to 12.2) during the mean follow-up of 15.6 months (range: 8-36 months).

CONCLUSION

Based on the results of this study, remaining ulnar TFCC remnants may be appropriate for sufficient stable repair using an arthroscopic one-tunnel transosseous suture technique after failed primary repair. However, only a small number of patients was examined. A larger number has to be investigated to confirm the promising preliminary results.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Anatomic based microfracture technique of insertion for rotator cuff repair in Vietnamese people: Case series study

Abstract

Postoperative tendon healing is still a matter of concern after rotator cuff repair. Several techniques have been introduced to help improve this healing process. Among them, the bone marrow is commonly used source and a research subject for methods using stem cells to promote wound healing process. A number of studies have shown that bone marrow stem cells can travel up through the holes on the rotator cuff insertion sites, contributing into the rotator cuff repair process, increasing the efficiency of tendon healing and improving clinical results.

Patients and methods

Cross-sectional descriptive study was performed on 41 rotator cuff tear patients. The microfractures for these patients were calculated beforehand, which have great depth but small diameter, based on the anatomical characteristic of the rotator cuff tear insertions of Vietnamese people. Patients' rotator cuff tendon healing processes were evaluated using ultrasound after surgery. Final tendon healing and clinical results ultimately rely on MRI assessments, classified according to Sugaya's classification, UCLA and ASES scale.

Results

No cases of rupture and fracture of the greater tubercle was recorded. There was a clear progression of tendon healing on ultrasound according to postoperative follow-up time-stamps (1 month, 3 months). MRI images evaluation also reveals at the latest follow-up time, according to Sugaya classification, the ratio of tendon healing was 87.8%, while the percentage of re-rupture was 12.2%. ASES and average UCLA scale were collected at the end of the study, respectively as 95.41 ± 5.45 and 32.36 ± 2.53.

Conclusion

The technique's microfractures characteristics based on the rotator cuff tear insertion anatomy ensures a secure, straightforward approach along with promising results in terms of tendon healing rate and postoperative functional outcomes.

Effect of difference in fixation methods of tendon graft and the microfracture procedure on tendon-bone junction healing

Background

There are generally two methods of fixation for tendon grafts used in ligament reconstruction: bone tunnel fixation and anchor fixation. The microfracture (Mf) procedure is a technique to induce bleeding from the bone marrow, and the bleeding may contain cells with differentiation potential. However, few studies have compared the effects of the Mf procedure with those of the fixation methods. This study aimed to evaluate the effectiveness of the Mf procedure on two tendon graft fixation methods: histological, gene expression, tendon graft thickness, and mechanical. We especially focused our investigation on junction healing of tendon grafts and bone in the two fixation methods.

Methods

We used 20 rabbits to evaluate tendon and bone healing in a peroneal tendon graft model. The rabbit models were divided into five groups according to the combination of peroneal tendon graft fixation method and Mf technique as follows: control group (C, n = 4), bone tunnel fixation without Mf procedure group (BT − Mf, n = 4), bone tunnel fixation with Mf procedure group (BT + Mf, n = 4), anchor fixation without Mf procedure group (A − Mf, n = 4), and anchor fixation with Mf procedure group (A + Mf, n = 4). All animals were sacrificed at 4 weeks postoperatively. The specimens underwent histological evaluation, mRNA analysis, tendon graft thickness at the tendon-bone junction, and biomechanical testing.

Results

Histological evaluation of the BT + Mf and A + Mf groups showed healing with fibrocartilage formation at the tendon graft-bone junction. The mRNA expression showed significant increase in type 2 collagen, Scleraxis, and SRY-box9 in the BT + Mf and A + Mf groups. In biomechanical tests, the BT + Mf and A + Mf groups showed significantly increased tensile strength compared with the BT − Mf and A − Mf groups (BT + Mf group, 21.6 ± 1.7 N; A + Mf group, 22.5 ± 2.3 N vs. BT − Mf group, 12.3 ± 2.4 N; A − Mf group, 11 ± 2.3 N).

Conclusion

The Mf procedure resulted in fibrocartilage formation at the tendon-bone junction in the BT and anchor fixation and improved the fixation strength at 4 weeks.

Rehabilitation variability after rotator cuff repair

BACKGROUND

There has been increasing recognition of the importance for standardized postoperative rehabilitation protocols. Despite published guidelines in 2016 by the American Society of Shoulder and Elbow Therapists (ASSET), optimal postoperative rehabilitation after rotator cuff repair (RCR) remains an area of active academic debate. The goals of this study were (1) to assess the variability of RCR rehabilitation protocols published online, (2) to study the congruence between online RCR rehabilitation protocols and the ASSET consensus statement, and (3) to identify differences in online RCR rehabilitation protocols from before and after 2016.

METHODS

A web-based search was conducted for publicly available RCR rehabilitation protocols from websites of all Accreditation Council for Graduate Medical Education (ACGME) academic orthopedic institutions. A supplemental 10-page Google search was also performed with the search terms "rotator cuff repair rehabilitation protocol." Collected protocols were grouped by tear size (small/medium or large/massive) and examined for information relating to the following categories: protocol demographics, adjunctive therapy use, immobilization/range of motion, and strengthening. Findings were compared to the ASSET statement's recommendations. Protocols published before and after ASSET's 2016 publication were compared for differences.

RESULTS

A total of 66 online RCR rehabilitation protocols were collected. Only 16 of 187 (8.5%) ACGME institutions provided online RCR rehabilitation protocols. The collected protocols recommend more aggressive rehabilitation in comparison to ASSET, specifically regarding immobilization time, passive range of motion initiation, active assisted range of motion initiation, and strengthening initiation (P < .001). Protocols published after 2016 trended toward more conservative recommendations in comparison to protocols published before 2016. Regardless of this trend, the majority of these recommendations were still largely more aggressive than ASSET's recommendations.

CONCLUSION

Despite an attempt by ASSET to provide standardization, this study highlights the marked variations that still exist regarding RCR rehabilitation. Additionally, online RCR rehabilitation protocols tend to make more aggressive recommendations than the ASSET consensus statement. Further research is needed to address these variations and to either validate, alter, or reject the ASSET recommendations.

In Vivo Imaging of Fibroblast Activity Using a 68Ga-Labeled Fibroblast Activation Protein Alpha (FAP-α) Inhibitor: Study in a Mouse Rotator Cuff Repair Model

BACKGROUND

Rotator cuff repair site failure is a well-established clinical concern. Tendon-to-bone healing is initiated by inflammatory mediators followed by matrix synthesis by fibroblasts. The kinetics of fibroblast accumulation and activity are currently poorly understood.

METHODS

Ninety-six mice underwent supraspinatus tendon repair. Six were used for imaging using a novel 68Gallium (Ga)-labeled fibroblast activation protein alpha (FAP-α) inhibitor and positron emission tomography-computed tomography (PET/CT) at days 0 (before surgery), 3, 7, 14, and 28. Sixty-eight animals were divided into 4 groups to be evaluated at 3, 7, 14, or 28 days. Twenty-two native shoulders from mice without surgery were used as the control group (intact tendon). Six animals from each group were used for histological analysis; 6 from each group were used for evaluation of fibroblastic response-related gene expression; and 10 mice each from the intact, 14-day, and 28-day groups were used for biomechanical testing.

RESULTS

There was minimal localization of 68Ga-labeled FAP-α inhibitor in the shoulders at day 0 (before surgery). There was significantly increased uptake in the shoulders with surgery compared with the contralateral sides without surgery at 3, 7, and 14 days. 68Ga-labeled FAP-α inhibitor uptake in the surgically treated shoulders increased gradually and peaked at 14 days followed by a decrease at 28 days. Gene expression for smooth muscle alpha (α)-2 (acta2), FAP-α, and fibronectin increased postsurgery followed by a drop at 28 days. Immunohistochemical analysis showed that FAP-α-positive cell density followed a similar temporal trend, peaking at 14 days. All trends matched closely with the PET/CT results. Biomechanical testing demonstrated a gradual increase in failure load during the healing process.

CONCLUSIONS

68Ga-labeled FAP-α inhibitor PET/CT allows facile, high-contrast in vivo 3-dimensional imaging of fibroblastic activity in a mouse rotator cuff repair model.

CLINICAL RELEVANCE

Noninvasive imaging of activated fibroblasts using labeled radiotracers may be a valuable tool to follow the progression of healing at the bone-tendon interface.

Engineering multi-tissue units for regenerative Medicine: Bone-tendon-muscle units of the rotator cuff

Our body systems are comprised of numerous multi-tissue units. For the musculoskeletal system, one of the predominant functional units is comprised of bone, tendon/ligament, and muscle tissues working in tandem to facilitate locomotion. To successfully treat musculoskeletal injuries and diseases, critical consideration and thoughtful integration of clinical, biological, and engineering aspects are necessary to achieve translational bench-to-bedside research. In particular, identifying ideal biomaterial design specifications, understanding prior and recent tissue engineering advances, and judicious application of biomaterial and fabrication technologies will be crucial for addressing current clinical challenges in engineering multi-tissue units. Using rotator cuff tears as an example, insights relevant for engineering a bone-tendon-muscle multi-tissue unit are presented. This review highlights the tissue engineering strategies for musculoskeletal repair and regeneration with implications for other bone-tendon-muscle units, their derivatives, and analogous non-musculoskeletal tissue structures.

Outcomes of Surgical Repair Versus Primary Tenodesis for Proximal Rectus Femoris Avulsion Injuries in Professional Athletes

BACKGROUND

Surgical repair of proximal rectus femoris avulsion injuries is associated with prolonged periods of rehabilitation and highly variable risk of injury recurrence. Surgical tenodesis of these injuries is often reserved for recurrent injuries or revision surgery. To our knowledge, the outcomes of proximal rectus femoris avulsion injuries treated with surgical repair versus primary tenodesis have not been previously reported.

HYPOTHESIS

Primary tenodesis of proximal rectus femoris avulsion injuries is associated with reduced risk of injury recurrence as compared with surgical repair.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study included 25 patients (22 male and 3 female) who underwent surgical repair versus 30 patients (26 male and 4 female) who received primary tenodesis for proximal rectus femoris avulsion injuries. Predefined outcomes were recorded at regular intervals after surgery. Mean follow-up time was 27.9 months (range, 24.0-31.7 months) from date of surgery.

RESULTS

All patients returned to their preinjury levels of sporting activity. Primary tenodesis was associated with earlier return to preinjury level of sporting function as compared with surgical repair (mean ± SD, 12.4 ± 1.6 vs 15.8 ± 2.2 weeks; P < .001) and reduced risk of recurrence (0% vs 16%; P < .001). At 1-year follow-up, there was no difference in surgical repair versus primary tenodesis relating to patient satisfaction scores (12 very satisfied and 13 satisfied vs 16 very satisfied and 14 satisfied; P = .70), isometric quadriceps strength (95.6% ± 2.8% vs 95.2% ± 6.3%; P = .31), Tegner scores (median [interquartile range], 9 [8-9] vs 9 [8-9]; P = .54), and lower extremity functional scores (73 [72-76] vs 74 [72-75]; P = .41). High patient satisfaction, quadriceps muscle strength, and functional outcome scores were maintained and remained comparable between treatment groups at 2-year follow-up.

CONCLUSION

Primary tenodesis was associated with reduced time for return to preinjury level of sporting function and decreased risk of injury recurrence when compared with surgical repair for proximal rectus femoris avulsion injuries. There were no differences in patient satisfaction, functional outcome scores, and quadriceps muscle strength between the treatment groups at 1- and 2-year follow-up.

Anatomic Restoration of the Biceps Brachii Insertion Through a Single Anterior Incision

Treatment of distal biceps tendon ruptures with surgical repair has been shown to restore peak elbow flexion and supination strength, as well as minimize fatigue with repetitive activity. The anatomic footprint of the biceps is slightly posterior to the apical prominence of the bicipital tuberosity. Single-incision and double-incision methods for repairing distal biceps tendon ruptures have been described. However, previously described single-incision techniques have been unable to accurately re-establish the anatomic position of the tendinous insertion. We describe our technique of performing an anatomic distal biceps repair using a single anterior incision. The proposed benefits of this technique include the restoration of the anatomic footprint area, insertion site, and consequently the native cam effect of the bicipital tuberosity all through a single incision. From a patient's perspective, the proposed benefit of this technique includes the restoration of supination strength using a single incision.

Intramedullary Cortical Button Repair for Distal Biceps Tendon Rupture: A Single-Center Experience

PURPOSE

The aim of this retrospective study was to evaluate the clinical outcome and complication rate of intramedullary cortical button repair for distal biceps tendon rupture (partial and complete tears).

METHODS

Between 2010 and 2014, a total of 28 patients with an acute distal biceps tendon rupture underwent intramedullary cortical button repair. Twenty-four patients (mean age, 49 years) with a mean follow-up of 28 months were included in the study. Twenty patients were examined clinically and by maximum isometric strength testing in flexion (at 90°) and supination of both arms. Twenty-four patients completed functional scores including the Mayo Elbow Performance Score (MEPS), the Andrews-Carson-Score (ACS) and the shortened Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire. Furthermore, follow-up radiographs of 24 patients were analyzed.

RESULTS

Compared with the contralateral elbow, the active range of motion (ROM) was the same. The mean strength for flexion was 100.8% ± 14% and for supination 93.1% ± 22% compared with the uninjured side. The mean MEPS for all patients was 95.6 ± 8.2, the mean ACS 194.2 ± 9.4 and the QuickDASH 3.8 ± 7.6. Heterotopic ossification (HO) was seen on radiographs in 46% of patients, but was symptomatic in only 1 patient. One patient suffered a tendon rerupture, and 1 asymptomatic button migration was seen in the follow-up.

CONCLUSIONS

Intramedullary cortical button repair provides good results with respect to strength, ROM, and functional outcomes. Because the posterior cortex is not violated, the risk of iatrogenic posterior interosseous nerve injury is minimized. However, the patient should be warned of a high prevalence of postoperative HO.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Sarcoid of the Upper Humerus Found Incidentally on MR Images Obtained for Work-Up of Rotator Cuff Tear Where Compromised Tissue Quality Was a Concern for Surgical Success

Sarcoidosis is an idiopathic systemic inflammatory disorder characterized histologically by noncaseating granulomas. The pathogenesis likely includes genetic, immunologic, and environmental factors. The lungs, skin, and eyes are most commonly affected. Although bone involvement is possible, sarcoidosis of the humerus is rare, with few cases reported. Furthermore, we are unaware of any reports of sarcoidosis of the upper humerus with a coexisting rotator cuff tear. We report the case of a 50-year-old female with sarcoidosis of the humerus and a coexisting tear of the supraspinatus tendon. Her medical history includes type 2 diabetes, depression, and fatigue. She had chronic shoulder pain that worsened after her dog jerked on the leash. Radiographs were grossly normal. Subsequent magnetic resonance imaging (MRI) demonstrated a possible small full-thickness rotator cuff tear. Multiple rounded lesions were also noted within the proximal humerus. A biopsy demonstrated noncaseating granulomas, confirming the diagnosis of sarcoidosis. There was concern that her sarcoid lesions would compromise bone quality, limiting options for surgical repair of her rotator cuff tear. However, it was determined that her lesion did not involve cortical bone, and surgery was performed. During surgery, the supraspinatus tendon was found to be partially torn and was treated with arthroscopic debridement and acromioplasty. An excellent result was ultimately achieved after her rheumatologist started adalimumab injections. This case demonstrates that there can be a rare incidental finding of osseous sarcoid lesions in the upper humerus where the bone might be compromised in the location of a planned rotator cuff repair.

Recurrent tears of the rotator cuff: Effect of repair technique and management options

Retears of the rotator cuff, following operative repair, is not an uncommon event. Various factors have been shown to influence recurrence including the technique of repair. Multiple techniques have been performed with varying results and complications. The repair technique significantly affects the rate and pattern of retears. Although risk of retears with double row and suture bridge techniques is relatively low, medial cuff failure is a potential complication which poses significant challenges when revision repair is undertaken. Modifications in surgical techniques in, both, double row and suture bridge repairs can help decrease the risk of medial cuff failure. Thorough analysis of retear rates and patterns reported, and their relation with the repair technique, provides new insights about the pathogenesis of rotator cuff retears, their future prevention and appropriate management.

Effects of Allogenic Dermal Fibroblasts on Rotator Cuff Healing in a Rabbit Model of Chronic Tear

BACKGROUND

The failure of rotator cuffs to heal after repair is an unresolved surgical issue. There have been substantial efforts, including the use of biological supplements, to enhance tendon healing. Dermal fibroblasts are a good candidate for tendon tissue engineering because they are similar to the tenocytes used for collagen synthesis. In addition, they are easily accessible because autologous dermal fibroblasts can be obtained from individual skin without major skin defects and allogenic dermal fibroblasts (ADFs) have already been commercialized in the field of skin engineering.

PURPOSE

To determine the effects of dermal fibroblasts on tendon-to-bone healing in a rabbit model of a chronic rotator cuff tear.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 33 rabbits were randomly allocated into 3 groups (n = 11 each). Supraspinatus tendons were detached and left for 6 weeks to establish a chronic rotator tear model. Torn tendons were repaired in a transosseous manner with the injection of 5 × 10⁶ ADFs with fibrin in group A, fibrin only in group B, and saline only in group C. At 12 weeks after repair, the mechanical test and histological evaluation were performed.

RESULTS

Seven rabbits died before the evaluation (1 in group A, 2 in group B, 4 in group C). In the final evaluation, the mean ± SD load to failure was 48.1 ± 13.3 N/kg for group A, 34.5 ± 8.9 N/kg for group B, and 31.1 ± 8.3 N/kg for group C, and group A showed significantly higher load-to-failure values than the other groups ( P = .011). The midsubstance tear rate, which presented stronger tendon-to-bone healing than insertional tear, was 50.0% in group A, 22.2% in group B, 28.6% in group C, but the differences were not statistically significant ( P = .413). In the histological evaluation, group A showed greater collagen fiber continuity and better orientation than the other groups.

CONCLUSION

This controlled laboratory study verified, on the basis of biomechanics and histology, the potential for the use of ADFs in rotator cuff healing. The current results suggest a new biological supplement to increase the rate of rotator cuff healing.

CLINICAL RELEVANCE

The most important finding of this study was the potential for a new biological supplement to enhance rotator cuff healing-a continuing challenge.

Does Greater Trochanter Decortication Affect Suture Anchor Pullout Strength in Abductor Tendon Repairs? A Biomechanical Study

BACKGROUND

Greater trochanter decortication is frequently performed at the time of abductor tendon repair to theoretically increase healing potential. No previous studies have determined the effect that greater trochanter decortication has on the pullout strength of suture anchors. Hypothesis/Purpose: The purpose of this study is to determine whether greater trochanter decortication and bone mineral density affect suture anchor pullout strength in abductor tendon repair. The authors hypothesize that both will have a significant detrimental effect on suture anchor pullout strength.

STUDY DESIGN

Controlled laboratory study.

METHODS

Nineteen cadaveric proximal femurs with accompanying demographic data and computed tomography scans were skeletonized to expose the greater trochanter. Bone density measurements were acquired by converting Hounsfield units to T-score, based on a standardized volumetric sample in the intertrochanteric region of the femur. The gluteus medius insertion site on the lateral facet of the greater trochanter was evenly divided into 2 regions, anterior-distal and posterior-proximal, and each region was randomly assigned to receive either no decortication or 2 mm of bone decortication. A single biocomposite anchor was implanted in each region and initially tested with cyclic loading for 10 cycles at 0-50 N, 0-100 N, 0-150 N, and 0-200 N, followed by load to failure (LTF) tested at 1 mm/s. For each trial, the number of cycles endured, LTF, mechanism of failure, and stiffness were recorded.

RESULTS

Greater trochanters with no decortication and 2 mm of decortication survived a mean ± SD 35.1 ± 6.4 and 28.5 ± 10.6 cycles, respectively ( P < .01). Load to failure for nondecorticated specimens was 206.7 ± 75.0 N versus 152.3 ± 60.2 N for decorticated specimens ( P < .001). In a multivariate analysis, decortication and bone density were determinants in LTF ( P < .05).

CONCLUSION

Decortication and decreased bone mineral density significantly decreased the pullout strength of suture anchors in the lateral facet of the greater trochanter.

CLINICAL RELEVANCE

Bone density should be considered when determining whether to perform greater trochanter decortication in abductor tendon repairs.

Primary and Secondary Consequences of Rotator Cuff Injury on Joint Stabilizing Tissues in the Shoulder

Rotator cuff tears (RCTs) are one of the primary causes of shoulder pain and dysfunction in the upper extremity accounting over 4.5 million physician visits per year with 250,000 rotator cuff repairs being performed annually in the U.S. While the tear is often considered an injury to a specific tendon/tendons and consequently treated as such, there are secondary effects of RCTs that may have significant consequences for shoulder function. Specifically, RCTs have been shown to affect the joint cartilage, bone, the ligaments, as well as the remaining intact tendons of the shoulder joint. Injuries associated with the upper extremities account for the largest percent of workplace injuries. Unfortunately, the variable success rate related to RCTs motivates the need for a better understanding of the biomechanical consequences associated with the shoulder injuries. Understanding the timing of the injury and the secondary anatomic consequences that are likely to have occurred are also of great importance in treatment planning because the approach to the treatment algorithm is influenced by the functional and anatomic state of the rotator cuff and the shoulder complex in general. In this review, we summarized the contribution of RCTs to joint stability in terms of both primary (injured tendon) and secondary (remaining tissues) consequences including anatomic changes in the tissues surrounding the affected tendon/tendons. The mechanical basis of normal shoulder joint function depends on the balance between active muscle forces and passive stabilization from the joint surfaces, capsular ligaments, and labrum. Evaluating the role of all tissues working together as a system for maintaining joint stability during function is important to understand the effects of RCT, specifically in the working population, and may provide insight into root causes of shoulder injury.

Comparison of Bone Tunnel and Cortical Surface Tendon-to-Bone Healing in a Rabbit Model of Biceps Tenodesis

BACKGROUND

Many orthopaedic surgical procedures involve reattachment of a single tendon to bone. Whether tendon-to-bone healing is better facilitated by tendon fixation within a bone tunnel or on a cortical surface is unknown. The purpose of this study was to evaluate tendon-healing within a bone tunnel compared with that on the cortical surface in a rabbit model of biceps tenodesis.

METHODS

Thirty-two rabbits (24 weeks of age) underwent unilateral proximal biceps tenodesis with tendon fixation within a bone tunnel (BT group) or on the cortical surface (SA [surface attachment] group). Postoperatively, rabbits were allowed free-cage activity without immobilization. All rabbits were killed 8 weeks after surgery. Healing was assessed by biomechanical testing, microcomputed tomography (micro-CT), and histomorphometric analysis.

RESULTS

Biomechanical testing demonstrated no significant difference between the groups in mean failure loads (BT: 56.8 ± 28.8 N, SA: 55.8 ± 14.9 N; p = 0.92) or stiffness (BT: 26.3 ± 16.6 N/mm, SA: 32.3 ± 9.6 N/mm; p = 0.34). Micro-CT analysis demonstrated no significant difference between the groups in mean volume of newly formed bone (BT: 69.3 ± 13.9 mm, SA: 65.5 ± 21.9 mm; p = 0.70) or tissue mineral density of newly formed bone (BT: 721.4 ± 10.9 mg/cm, SA: 698.6 ± 26.2 mg/cm; p = 0.07). On average, newly formed bone within the tunnel represented only 5% of the total new bone formed in the BT specimens. Histological analysis demonstrated tendon-bone interdigitation and early fibrocartilaginous zone formation on the outer cortical surface in both groups. In contrast, minimal tendon-bone bonding was observed within the tunnel in the BT specimens.

CONCLUSIONS

Tendon fixation in a bone tunnel and on the cortical surface resulted in similar healing profiles. For tendons placed within a bone tunnel, intratunnel healing was minimal compared with the healing outside the tunnel on the cortical surface.

CLINICAL RELEVANCE

The creation of large bone tunnels, which can lead to stress risers and increase the risk of fracture, may not be necessary for biceps tenodesis procedures.

[Arthroscopic rotator cuff surgery : New and established methods]

This present article summarizes established and current developments and aspects of rotator cuff surgery. Achieved milestones as well as current approaches are presented and assessed with respect to their clinical and radiographic impact. Despite biomechanical and technical improvements in modern rotator cuff repair techniques, re-defect and re-tearing rates could not be fully eliminated. Meanwhile, the importance of biological processes around successful tendon-bone reintegration has been increasingly recognized. Hence, this article presents the current scientific standing regarding biological growth factors, platelet-rich plasma and rotator cuff augmentation techniques (with allogenic/autologous grafts). In summary, there are clear biomechanical advantages as well as many promising approaches to biological augmentation; however, the latter have not yet been transferred into regular clinical application.

Application of a Demineralized Cortical Bone Matrix and Bone Marrow-Derived Mesenchymal Stem Cells in a Model of Chronic Rotator Cuff Degeneration

BACKGROUND

The success of rotator cuff repair is primarily dependent on tendon-bone healing. Failure is common because weak scar tissue replaces the native enthesis, rendering it prone to reruptures. A demineralized bone matrix (DBM) consists of a network of collagen fibers that provide a sustained release of growth factors such as bone morphogenetic proteins. Previous studies have demonstrated that it can regenerate a fibrocartilaginous enthesis.

HYPOTHESIS

The use of a DBM and mesenchymal stem cells (MSCs) at the healing enthesis will result in a higher bone mineral density at the tendon insertion and will enhance the regeneration of a morphologically superior enthesis when compared with an acellular human dermal matrix.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eighteen female Wistar rats underwent unilateral detachment of the supraspinatus tendon. Three weeks later, tendon repair was carried out in animals randomized into 3 groups: group 1 received augmentation of the repair with a cortical allogenic DBM (n = 6); group 2 received augmentation with a nonmeshed, ultrathick, acellular human dermal matrix (n = 6); and group 3 underwent tendon-bone repair without a scaffold (n = 6). All animals received 1 × 10⁶ MSCs delivered in fibrin glue to the repair site. Specimens were retrieved at 6 weeks postoperatively for histological analysis and the evaluation of bone mineral density.

RESULTS

All groups demonstrated closure of the tendon-bone gap with a fibrocartilaginous enthesis. Although there were no significant differences in the enthesis maturation and modified Movin scores, repair augmented with a dermal matrix + MSCs exhibited a disorganized enthesis, abnormal collagen fiber arrangement, and greater cellularity compared with other MSC groups. Only repairs augmented with a DBM + MSCs reached a bone mineral density not significantly lower than nonoperated controls.

CONCLUSION

A DBM enhanced with MSCs can augment rotator cuff healing at 6 weeks and restore bone mineral density at the enthesis to its preinjury levels.

CLINICAL RELEVANCE

Biological augmentation of rotator cuff repair with a DBM and MSCs may reduce the incidence of retears, although further studies are required to determine its effectiveness.

Demineralized Bone Matrix to Augment Tendon-Bone Healing: A Systematic Review

Background:

Following injury to the rotator cuff and anterior cruciate ligament, a direct enthesis is not regenerated, and healing occurs with biomechanically inferior fibrous tissue. Demineralized bone matrix (DBM) is a collagen scaffold that contains growth factors and is a promising biological material for tendon and ligament repair because it can regenerate a direct fibrocartilaginous insertion via endochondral ossification.

Purpose:

To provide a comprehensive review of the literature investigating the use of DBM to augment tendon-bone healing in tendon repair and anterior cruciate ligament reconstruction (ACLR).

Study Design:

Systematic review.

Methods:

Electronic databases (MEDLINE and EMBASE) were searched for preclinical and clinical studies that evaluated the use of DBM in tendon repair and ACLR. Search terms included the following: (“demineralized bone matrix” OR “demineralized cortical bone”) AND (“tissue scaffold” OR “tissue engineering” OR “ligament” OR “tendon” OR “anterior cruciate ligament” OR “rotator cuff”). Peer-reviewed articles written in English were included, and no date restriction was applied (searches performed February 10, 2017). Methodological quality was assessed with peer-reviewed scoring criteria.

Results:

The search strategy identified 339 articles. After removal of duplicates and screening according to inclusion criteria, 8 studies were included for full review (tendon repair, n = 4; ACLR, n = 4). No human clinical studies were identified. All 8 studies were preclinical animal studies with good methodological quality. Five studies compared DBM augmentation with non-DBM controls, of which 4 (80%) reported positive findings in terms of histological and biomechanical outcomes.

Conclusion:

Preclinical evidence indicates that DBM can improve tendon-bone healing, although clinical studies are lacking. A range of animal models of tendon repair and ACLR showed that DBM can re-create a direct fibrocartilaginous enthesis, although the animal models are not without limitations. Before clinical trials are justified, research is required that determines the best source of DBM (allogenic vs xenogenic) and the best form of DBM (demineralized cortical bone vs DBM paste) to be used in them.

Biomechanical Analysis of Bilateral Facet Joint Stabilization Using Bioderived Tendon for Posterior Cervical Spine Motion Reservation in Goats

OBJECTIVES

To investigate the biomechanical properties of a novel stabilization method for posterior cervical motion preservation using bioderived freeze-dried tendon.

METHODS

Experiments were conducted both in vitro and in vivo. For the in vitro group, 15 fresh-frozen goat spines (C1-C7) were randomly divided into 3 subgroups: intact (INT-vitro, n = 5), injury model (IM-vitro, n = 5), and bilateral facet joint stabilization (BFJS-vitro, n = 5) subgroups. For the in vivo group, 15 adult goats were randomly divided into 3 experimental subgroups: INT-vivo subgroup (n = 5), IM-vivo subgroup (n = 5), and BFJS-vivo subgroup (n = 5). Goats in the in vivo group were euthanized 12 weeks after surgery. Biomechanical tests were performed to evaluate range of motion. Histologic analysis was conducted to evaluate survival and reactions associated with the bioderived tendon.

RESULTS

Compared with the INT-vitro and INT-vivo subgroups, the flexion of IM-vitro and IM-vivo subgroups increased significantly, respectively (P < 0.05). The flexion of the BFJS-vitro and BFJS-vivo subgroups was significantly smaller than in the IM-vitro and IM-vivo subgroups, respectively (P < 0.05). Significant differences between the BFJS-vitro and BFJS-vivo subgroups were observed in flexion, lateral bending, and rotation (P < 0.05). Histologic evaluation demonstrated that fibers arranged regularly and stained homogeneously. New vessels in growth indicated that the bioderived tendon was survival and processed good regeneration.

CONCLUSIONS

Bilateral facet joint stabilization can significantly limit excessive flexion motion and maintain adequate stability. Furthermore, the preservation of extension motions without limiting lateral bending and rotation ideally simulates the features of the posterior ligamentous complex. This preserves the dynamic stability of the lower cervical spine.

Effect of Footprint Preparation on Tendon-to-Bone Healing: A Histologic and Biomechanical Study in a Rat Rotator Cuff Repair Model

PURPOSE

To compare the histologic and biomechanical effects of 3 different footprint preparations for repair of tendon-to-bone insertions and to assess the behavior of bone marrow-derived cells in each method of insertion repair.

METHODS

We randomized 81 male Sprague-Dawley rats and green fluorescent protein-bone marrow chimeric rats into 3 groups. In group A, we performed rotator cuff repair after separating the supraspinatus tendon from the greater tuberosity and removing the residual tendon tissue. In group B, we also drilled 3 holes into the footprint. The native fibrocartilage was preserved in groups A and B. In group C, we excavated the footprint until the cancellous bone was exposed. Histologic repair of the tendon-to-bone insertion, behavior of the bone marrow-derived cells, and ultimate force to failure were examined postoperatively.

RESULTS

The areas of metachromasia in groups A, B, and C were 0.033 ± 0.019, 0.089 ± 0.022, and 0.002 ± 0.001 mm²/mm², respectively, at 4 weeks and 0.029 ± 0.022, 0.090 ± 0.039, and 0.003 ± 0.001 mm²/mm², respectively, at 8 weeks. At 4 and 8 weeks postoperatively, significantly higher cartilage matrix production was observed in group B than in group C (4 weeks, P = .002; 8 weeks, P < .001). In green fluorescent protein-bone marrow chimeric rats in group B, bone marrow-derived chondrogenic cells infiltrated the fibrocartilage layer. Ultimate force to failure was significantly higher in group B (19.7 ± 3.4 N) than in group C (16.7 ± 2.0 N) at 8 weeks (P = .031).

CONCLUSIONS

Drilling into the footprint and preserving the fibrocartilage improved the quality of repair tissue and biomechanical strength at the tendon-to-bone insertion after rotator cuff repair in an animal model.

CLINICAL RELEVANCE

Drilling into the footprint and preserving the fibrocartilage can enhance repair of tendon-to-bone insertions. This method may be clinically useful in rotator cuff repair.

Editorial Commentary: Remnant-Preserving Philosophy Extended to Rotator Cuff Repair: Can We Improve Tendon Healing by Preserving the Native Insertional Fibrocartilage?

Tendon-to-bone healing in rotator cuff repair is affected by the method of footprint preparation. Bone drilling and preserving the native fibrocartilage at the tendon attachment site improved tissue quality and mechanical strength of bone-tendon interface in an animal model.

Length of time between surgery and return to sport after ulnar collateral ligament reconstruction in Major League Baseball pitchers does not predict need for revision surgery

HYPOTHESIS

Pitchers who return to sport (RTS) sooner will have a higher risk of revision ulnar collateral ligament reconstruction (UCLR) than those who return later.

METHODS

All professional (major and minor league) baseball pitchers who underwent UCLR between 1974 and 2016 were identified. Date of the index UCLR was recorded. The date of the first game back at any professional level after surgery and the date the pitcher returned to the same level of play (if applicable) were recorded. Length of time between these dates was compared for pitchers who required a revision UCLR and those who did not.

RESULTS

Overall, 569 pitchers (average age, 24.8 ± 4.1 years) underwent UCLR and had reliable game logs after surgery. No statistically significant difference existed in the length of time to RTS at any professional level or at the same professional level between those pitchers who did not require a revision UCLR and those who did (P = .442, P = .238). Pitchers who required revision UCLR returned to any level of play almost 2 months earlier (14.7 vs. 16.5 months) and returned to the same level of play >2 months earlier (15.2 vs. 17.7 months) than matched controls who did not require revision UCLR, although this was not statistically significant (P = .179, P = .204).

CONCLUSION

No statistically significant difference existed in the length of time to RTS after UCLR in professional baseball players who required a revision UCLR and those who did not.

The influence of different footprint preparation techniques on tissue regeneration in rotator cuff repair in an animal model

INTRODUCTION

Rotator cuff tears are common diseases of the upper extremity. There are no recommendations to the surgeon on how to prepare the footprint to ensure optimal tendon-to-bone healing. However, biologic augmentation using stem cells and growth factors is considered to encourage the healing process of the tendon. The aim of the study was to investigate the biomechanical and histological outcome of different footprint preparations in rotator cuff repair.

MATERIAL AND METHODS

One hundred and eighty-nine Sprague-Dawley rats were randomly assigned to either spongialization, radiofrequency ablation or an untreated control group. Rats were killed after 1 or 7 weeks for histological evaluation or after 7 weeks for biomechanical testing.

RESULTS

Histological evaluation showed better tissue organization in the control and spongialization group compared to the radiofrequency ablation group. The highest collagen I to collagen III quotient was found in the control group, followed closely by the spongialization group. Measured quotients showed a decrease in the values after 1 week compared to the values after 7 weeks, except in the radiofrequency ablation group, where an increase was detected. A significant difference was found in the load to failure test comparing the radiofrequency ablation group to the spongialization group (p = 0.0409) and control group (p = 0.014), but not comparing the spongialization group to the control group (p = 0.2456).

CONCLUSIONS

The results of this study suggest that spongialization of the footprint before attaching the torn supraspinatus tendon can lead to better structural properties and higher quality of tendon-to-bone restoration at the insertion area when compared with radiofrequency ablation.

Surgical Management of Rectus Femoris Avulsion Among Professional Soccer Players

BACKGROUND

Rectus femoris injuries are common among athletes, especially in kicking sports such as soccer; however, proximal rectus femoris avulsions in athletes are a relatively rare entity.

PURPOSE/HYPOTHESIS

The purpose of this study was to describe and report the results of an original technique of surgical excision of the proximal tendon remnant followed by a muscular suture repair. Our hypothesis was that this technique limits the risk of recurrence in high-level athletes and allows for rapid recovery without loss of quadriceps strength.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Our retrospective series included 5 players aged 31.8 ± 3.9 years with acute proximal rectus femoris avulsion injuries who underwent a surgical resection of the proximal tendon between March 2012 and June 2014. Four of these players had recurrent rectus femoris injuries in the 9 months before surgery, while 1 player had surgery after a first injury. Mean follow-up was 18.2 ± 12.6 months, and minimum follow-up was 9 months. We analyzed the age, sex distribution, physical examination outcomes, type and mechanism of injury, diagnosis, treatment and complications during surgery, postoperative follow-up, and time to return to play. The Lower Extremity Functional Scale (LEFS) and Marx scores were obtained at 3-month follow-up, and isokinetic tests were performed before return to sports. A telephone interview was completed to determine the presence of recurrence at an average follow-up of 18.2 months.

RESULTS

At 3-month follow-up, all patients had Marx activity scores of 16 and LEFS scores of 80. Return to the previous level of play occurred at a mean of 15.8 ± 2.6 weeks after surgery, and none of the athletes suffered a recurrence. Isokinetic test results were comparable between both sides.

CONCLUSION

The surgical treatment of proximal rectus femoris avulsions, consisting of resection of the tendinous part of the muscle, is a reliable and safe technique allowing a fast recovery in professional athletes.

Distal biceps tendon history, updates, and controversies: from the closed American Shoulder and Elbow Surgeons meeting-2015

Understanding of the distal biceps anatomy, mechanics, and biology during the last 75 years has greatly improved the physician's ability to advise and to treat patients with ruptured distal tendons. The goal of this paper is to review the past and current advances on complete distal biceps ruptures as well as controversies and future directions that were discussed and debated during the closed American Shoulder and Elbow Surgeons meeting in 2015.

Three-dimensional ultrastructural analysis of development at the supraspinatus insertion by using focused ion beam/scanning electron microscope tomography in rats

To obtain a successful outcome after rotator cuff repair, the repaired tendon must be biologically anchored to the bone. However, the histological structure at the repaired tendon-bone interface differs from that of the site of normal tendon insertion. Therefore, analyzing postnatal development in detail will contribute to understanding the repaired tendon-bone interface after rotator cuff repair. In this study, we analyzed postnatal development at the tendon-bone insertion in terms of temporal changes in SOX9/SCX expression and three-dimensional (3D) ultrastructure with FIB/SEM tomography, a new scanning electron microscopic method. Sixteen postnatal Sprague-Dawley rats were used for the study. One-, two-, three-, and four-week-old rats were sacrificed and both right and left shoulders were removed; eight normal supraspinatus tendon insertions were isolated for each time point. At each time point, four specimens were evaluated with fluorescent immunostaining for SOX9/SCX expression, and the remaining four specimens were evaluated with FIB/SEM tomography. Even in postnatal development, SOX9(+) /SCX(+) expression was observed at the tendon insertion; expression gradually decreased with postnatal development at the normal tendon insertion. In 3D ultrastructure, the morphology of the cells and the number/orientation of the cell processes drastically changed by postnatal week 4. The pattern of SOX9/SCX expression and 3D ultrastructural changes obtained in this study contribute to an understanding of the complicated development of normal tendon-bone insertion. Therefore, this study helps elucidate the pathophysiology of tendon-bone insertion, especially in cases of rotator cuff tear and repair. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:969-976, 2016.

The American Society of Shoulder and Elbow Therapists' consensus statement on rehabilitation following arthroscopic rotator cuff repair

This is a consensus statement on rehabilitation developed by the American Society of Shoulder and Elbow Therapists. The purpose of this statement is to aid clinical decision making during the rehabilitation of patients after arthroscopic rotator cuff repair. The overarching philosophy of rehabilitation is centered on the principle of the gradual application of controlled stresses to the healing rotator cuff repair with consideration of rotator cuff tear size, tissue quality, and patient variables. This statement describes a rehabilitation framework that includes a 2-week period of strict immobilization and a staged introduction of protected, passive range of motion during weeks 2-6 postoperatively, followed by restoration of active range of motion, and then progressive strengthening beginning at postoperative week 12. When appropriate, rehabilitation continues with a functional progression for return to athletic or demanding work activities. This document represents the first consensus rehabilitation statement developed by a multidisciplinary society of international rehabilitation professionals specifically for the postoperative care of patients after arthroscopic rotator cuff repair.

Suture Anchor Biomechanics After Rotator Cuff Footprint Decortication

PURPOSE

To identify the biomechanical consequences of violating the cortical shelf when preparing the greater tuberosity for suture anchor repair.

METHODS

Demographic information and bone mineral density were obtained for 20 fresh-frozen human humeri (10 matched pairs). Suture anchors were placed at a predetermined location in decorticated and non-decorticated settings after randomization. Anchors were tested under cyclic loads followed by load-to-failure testing. The number of cycles, failure mode, stiffness, and final pullout strength were recorded.

RESULTS

Nineteen specimens met the inclusion criteria for final testing. A significant difference in mean ultimate load to failure was seen between the non-decorticated specimens (244.04 ± 89.06 N/mm) and the decorticated humeri (62.84 ± 38.04 N/mm, P < .0001). Regression analysis showed positive correlations with female gender and decreased bone mineral density (P = .008 and P = .0005, respectively).

CONCLUSIONS

Decortication of the rotator cuff footprint significantly decreases the pullout strength of the suture anchor. Gender and bone mineral density also play a significant role in bone-anchor biomechanics and should be considered during repair.

CLINICAL RELEVANCE

Caution should be exercised when preparing the rotator cuff footprint before suture anchor placement because of the significant risk of early repair failure at the bone-anchor interface.

Characterization of progenitor cells derived from torn human rotator cuff tendons by gene expression patterns of chondrogenesis, osteogenesis, and adipogenesis

Background

It is important to regenerate the tendon-to-bone interface after rotator cuff repair to prevent re-tears. The cells from torn human rotator cuff were targeted, and their capacity for multilineage differentiation was investigated.

Methods

The edges of the rotator cuff were harvested during arthroscopic rotator cuff repair from nine patients, minced into pieces, and cultured on dishes. Adherent cells were cultured, phenotypically characterized. Then expandability, differentiation potential and gene expression were analyzed.

Results

Flow cytometry revealed that the mesenchymal stem cells (MSC)-related markers CD29, CD44, CD105, and CD166 were positive. However, CD14, CD34, and CD45 were negative. On RT-PCR analyses, the cells showed osteogenic, adipogenic, and chondrogenic potential after 3 weeks of culture under the respective differentiation conditions. In addition, SOX9, type II collagen, and type X collagen expression patterns during chondrogenesis were similar to those of endochondral ossification at the enthesis.

Conclusions

The cells derived from torn human rotator cuff are multipotent mesenchymal stem cells with the ability to undergo multilineage differentiation, suggesting that MSCs form this tissue could be regenerative capacity for potential self-repair.

[Clinical management of rotator cuff tears. Current concepts in cell-based therapy strategies]

Due to the increasing demand for functionality in an aging yet physically active society, the treatment of rotator cuff tears is of ever-growing importance. Despite intensive research efforts, the treatment of degenerative rotator cuff tears, in particular their long-term outcome, is still a challenge. While in recent years the focus was on biomechanics and the technical aspects of rotator cuff reconstruction, attention has now turned to the biological considerations of tendon regeneration. This article highlights the current state of biological rotator cuff augmentation in a clinical setting and provides an insight into and an outlook on the experimental procedures.

Evaluation of a collagen-coated, resorbable fiber scaffold loaded with a peptide basic fibroblast growth factor mimetic in a sheep model of rotator cuff repair

BACKGROUND

A new scaffold design combined with a peptide growth factor was tested prospectively for safety and for improved tendon healing in sheep.

METHODS

The infraspinatus tendon was detached and then surgically repaired to the humerus using sutures and anchors in 50 adult sheep. The repairs in 40 of these sheep were reinforced with a scaffold containing F2A, a peptide mimetic of basic fibroblast growth factor. The sheep were examined after 8 or 26 weeks with magnetic resonance imaging, full necropsy, and histopathologic analysis. A second cohort of 30 sheep underwent surgical repair--20 with scaffolds containing F2A. The 30 shoulders were tested mechanically after 8 weeks.

RESULTS

The scaffold and F2A showed no toxicity. Scaffold-repaired tendons were 31% thicker than surgically repaired controls (P = .037) at 8 weeks. There was more new bone formed at the tendon footprint in sheep treated with F2A. Surgically repaired tendons delaminated from the humerus across 14% of the footprint area. The extent of delamination decreased to 1.3% with increasing doses of F2A (P = .004). More of the repair tissue at the footprint was tendon-like in the peptide-treated sheep. On mechanical testing, only 7 shoulders tore at the repair site. The repairs in the other 23 shoulders were already stronger than the midsubstance tendon at 8 weeks.

CONCLUSIONS

The new scaffold and peptide safely improved tendon healing.

Assessment of the Postoperative Appearance of the Rotator Cuff Tendon Using Serial Sonography After Arthroscopic Repair of a Rotator Cuff Tear

OBJECTIVES

The purpose of this study was to evaluate serial changes in sonographic findings of a rotator cuff tendon after rotator cuff repair.

METHODS

Sixty-five arthroscopically repaired rotator cuff tears (43 full-thickness tears and 22 partial-thickness tears) were retrospectively included in this study. Serial sonographic examinations were performed at 5 weeks, 3 months, and 6 months after surgery. The sonographic findings of the repaired tendon were assessed for a recurrent tear, tendon thickness, morphologic tendon characteristics, vascularity, and bursitis at each time point.

RESULTS

Four recurrent tears occurred within 3 months of surgery. The postoperative tendon thickness decreased from 5 weeks to 6 months after surgery (P = .001). There were significant changes in the morphologic tendon characteristics, including the echo texture, fibrillar pattern, and surface irregularity of the repaired tendon, from 5 weeks to 6 months after surgery (P < .001). Additionally, subacromial-subdeltoid bursitis and the vascularity of the repaired tendon decreased postoperatively over time.

CONCLUSIONS

Serial sonography after arthroscopic rotator cuff repair was useful for monitoring the postoperative changes in a repaired tendon. The morphologic appearance of the repaired tendon and peritendinous soft tissue changes improved over time and nearly normalized within 6 months of surgery.

Novel single-loop and double-loop knot stitch in comparison with the modified Mason-Allen stitch for rotator cuff repair

PURPOSE

In rotator cuff repair, strong and long-lasting suturing techniques that do not require additional implants are needed. This study examines the ultimate load to failure and the Young's modulus at the suture-tendon interface for a novel single-loop knot stitch and double-loop knot stitch. These values are compared to those of the modified Mason-Allen stitch.

METHODS

Twenty-four infraspinatus muscles with tendons were dissected from porcine shoulders (twelve Goettingen minipigs). The preparations were randomly allocated to three groups of eight samples. Load-to-failure testing of the single-loop knot stitch, the double-loop knot stitch and the mMAS were performed using a Zwick 1446 universal testing machine (Zwick-Roell AG, Ulm, Germany).

RESULTS

The highest ultimate load to failure for the three techniques occurred with the double-loop knot stitch with a median value of 382.2 N (range 291.8-454.2 N). These values were significantly higher than those of the single-loop knot stitch, which had a median value of 259.5 N (range 139.6-366.3 N) and the modified Mason-Allen stitch, which had a median value of 309.3 N (range 84.55-382.9 N). The values of the single-loop knot stitch and the modified Mason-Allen stitch did not differ significantly. Regarding the Young's modulus, no significant differences were found between the double-loop knot stitch with a median value of 496.02 N/mm² (range 400.4-572.6 N/mm²) and the modified Mason-Allen stitch with 498.5 N/mm² (range 375.5-749.2 N/mm²) with respect to the stiffness of the suture-tendon complex. The median value for the Young's modulus of the single-loop knot stitch of 392.1 N/mm² (range 285.7-510.6 N/mm²) was significantly lower than those of the double-loop knot stitch and modified Mason-Allen stitch.

CONCLUSION

This in vitro animal study demonstrated that both the single-loop knot stitch and the double-loop knot stitch have excellent ultimate load-to-failure properties when used for rotator cuff repair. The introduced single-loop knot stitch and double-loop knot stitch offer an alternative to other common used stitch techniques in rotator cuff repair.

Mini-open incision for distal biceps repair by suture anchors: follow-up of eighteen patients

BACKGROUND

This clinical trial was done to describe a mini approach for distal biceps repair using two or three suture anchors.

PATIENTS AND METHODS

Twenty patients have undergone surgical repair over the last 10 years. All patients were males with mean age 46.8 (range 35-72), and dominant arm was involved in 70 %. Eighteen patients were evaluated with subjective and objective criteria including patient's satisfaction, active range of motion (ROM), and maximum isometric strength (in supination and flexion) using Cybex dynamometer. Functional scoring included Mayo Elbow Performance Score, Disabilities of the Arm, Shoulder and Hand score and Oxford Elbow Score.

RESULTS

Eighty percent of patients were highly satisfied, with excellent results as defined by Mayo and Oxford Elbow score. Compared to contralateral, the active ROM was not affected in flexion and extension, but pronation and supination were decreased by 5°-10° in two cases. One of eighteen showed hypoesthesia of first and second fingers, and one of eighteen showed a symptomatic heterotopic ossification. There were no reruptures.

CONCLUSIONS

Surgical repair of distal biceps tendon with a mini-single-incision as we described provides patient's satisfaction and very good results with respect to ROM and functional scoring, with a low complication rate.

The influence of intraoperative factors and postoperative rehabilitation compliance on the integrity of the rotator cuff after arthroscopic repair

BACKGROUND

The purpose of this study was to determine when cuff re-tear commonly occurs in the postoperative period and to investigate the clinical factors that might predispose to an early cuff re-tear.

METHODS

All patients with rotator cuff (supraspinatus ± infraspinatus) tear that required arthroscopic repair during the period between June 1, 2010, and May 31, 2012, with completed serial ultrasound examinations at 6 weeks, 12 weeks, and 26 weeks postoperatively were included. Intraoperative findings were noted. Functional clinical outcomes were assessed by Constant score, Western Ontario Rotator Cuff Index, and Oxford score. Compliance of patients with postoperative rehabilitation was established.

RESULTS

There were 127 cases; the mean age of patients was 60 years. Overall re-tear rate was 29.1%. The percentage of new re-tears was significantly higher in the first 12 weeks than in the second 12 weeks postoperatively (25.2% and 3.9%, respectively). The patient's postoperative compliance was a significant prognostic factor for re-tearing. Significant associations were also found between re-tear and primary tear size, tendon quality, repair tension, cuff retraction, and footprint coverage. Poor compliance of patients was highest (17.3%) during the second 6 weeks postoperatively. Better functional outcomes were noted in patients who had re-torn their cuffs at the 12-week period (Oxford mean scores, P = .04).

CONCLUSIONS

Understanding of the predisposing factors will assist in predicting the prognosis of the repaired rotator cuff. Despite the progress of patients' functions postoperatively, an early significant improvement of the clinical outcome should be a warning sign to a surgeon that the patient's compliance may be suboptimal, resulting in an increased risk of the cuff's re-tearing.

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.