Orthopedic applications of acellular human dermal allograft for shoulder and elbow surgery

Advances, challenges, and future directions in the clinical translation of ECM biomaterials for regenerative medicine applications

Extracellular Matrix (ECM) scaffolds and biomaterials have been widely used for decades across a variety of diverse clinical applications and have been implanted in millions of patients worldwide. ECM-based biomaterials have been especially successful in soft tissue repair applications but their utility in other clinical applications such as for regeneration of bone or neural tissue is less well understood. The beneficial healing outcome with the use of ECM biomaterials is the result of their biocompatibility, their biophysical properties and their ability to modify cell behavior after injury. As a consequence of successful clinical outcomes, there has been motivation for the development of next-generation formulations of ECM materials ranging from hydrogels, bioinks, powders, to whole organ or tissue scaffolds. The continued development of novel ECM formulations as well as active research interest in these materials ensures a wealth of possibilities for future clinical translation and innovation in regenerative medicine. The clinical translation of next generation formulations ECM scaffolds faces predictable challenges such as manufacturing, manageable regulatory pathways, surgical implantation, and the cost required to address these challenges. The current status of ECM-based biomaterials, including clinical translation, novel formulations and therapies currently under development, and the challenges that limit clinical translation of ECM biomaterials are reviewed herein.

Gouty destruction of a patellar tendon reconstruction and novel revision reconstruction technique: A case report

BACKGROUND

Gout is a disease characterized by hyperuricemia, and resultant deposition of uric acid crystals in tissues. While typically manifested as intraarticular crystals or tophi, gout can also cause pathology at entheses. Gouty deposition within tendinous structures put them at risk for traumatic and degenerative rupture. Furthermore, allografts can also be at risk of rupture in the setting of severe gout. We present the case of a 56-year-old female with severe gouty disease who sustained a re-rupture of a patellar tendon allograft reconstruction.

CASE SUMMARY

A 56-year-old female presented to clinic after feeling her left knee pop and collapse beneath her while descending stairs. She had a history of tophaceous gout and left patellar tendon rupture with reconstruction and multiple revisions over the course of 19 years. This patient presented with pain and extensor lag. A magnetic resonance image demonstrated a ruptured patellar tendon allograft reconstruction and avulsion fracture at the tibial tubercle. The patient was treated with a novel intervention of Achilles allograft with bone block in a unique configuration with a dermal allograft incorporated into the reconstruction. She was made non-weight bearing in the operative extremity in extension for the first four weeks postoperatively and was then progressed to active flexion over the course of eight weeks. At twelve weeks, she was able to fully extend her operative knee and at five months she was resuming her normal activities and exercises.

CONCLUSION

Failed patellar tendon reconstruction due to gouty infiltration is treated with dermal allograft augmented Achilles tendon reconstruction with bone block.

Surgical Treatment and Outcomes for Gluteal Tendon Tears

PURPOSE OF REVIEW

Gluteus medius and minimus tears, or hip abductor tendon tears, are increasingly identified as a source of lateral hip pain. Once underappreciated and undertreated, they are now recognized as a cause of greater trochanteric pain syndrome and a pathology amenable to both nonoperative and operative modalities. This review summarizes relevant anatomy, clinical presentation, and treatment options for gluteus medius tears, focusing on surgical options.

RECENT FINDINGS

When surgical intervention is indicated, repair, reconstruction, or tendon transfer may be considered. Open and endoscopic repair techniques demonstrate similar outcomes with improvements in patient-reported outcomes and low complication and retear rates for both partial and full thickness tears. Variations in fixation construct and graft augmentations have been described, though clinical evidence remains limited to support specific techniques. Gluteus maximus transfer via open approach is a salvage option for the severely atrophied, retracted, or revision gluteus tendon; however, persistent limitations in abduction strength and gait abnormalities are common. Emerging evidence continues to evolve our understanding of surgical decision-making for gluteus tendon tears. The current literature supports either open or endoscopic repair techniques and open tendon transfer as a salvAage option. Further study is needed to determine the optimal fixation construct, the role of graft augmentation, and patient-related factors that influence postoperative outcomes.

Current trends in the prevention of adhesions after zone 2 flexor tendon repair

Treating flexor tendon injuries within the digital flexor sheath (commonly referred to as palmar hand zone 2) presents both technical and logistical challenges. Success hinges on striking a delicate balance between safeguarding the surgical repair for tendon healing and initiating early rehabilitation to mitigate the formation of tendon adhesions. Adhesions between tendon slips and between tendons and the flexor sheath impede tendon movement, leading to postoperative stiffness and functional impairment. While current approaches to flexor tendon repair prioritize maximizing tendon strength for early mobilization and adhesion prevention, factors such as pain, swelling, and patient compliance may impede postoperative rehabilitation efforts. Moreover, premature mobilization could risk repair failure, necessitating additional surgical interventions. Pharmacological agents offer a potential avenue for minimizing inflammation and reducing adhesion formation while still promoting normal tendon healing. Although some systemic and local agents have shown promising results in animal studies, their clinical efficacy remains uncertain. Limitations in these studies include the relevance of chosen animal models to human populations and the adequacy of tools and measurement techniques in accurately assessing the impact of adhesions. This article provides an overview of the clinical challenges associated with flexor tendon injuries, discusses current on- and off-label agents aimed at minimizing adhesion formation, and examines investigational models designed to study adhesion reduction after intra-synovial flexor tendon repair. Understanding the clinical problem and experimental models may serve as a catalyst for future research aimed at addressing intra-synovial tendon adhesions following zone 2 flexor tendon repair.

Prospective Outcomes of a Biological Resurfacing Arthroplasty with Fascia Lata Autograft (BioJoint) for the Treatment of Osteoarthritis of the Midtarsal Joint Complex

OBJECTIVE

To determine the clinical, safety, and radiological outcomes after biological resurfacing arthroplasty for the treatment of osteoarthritis (OA) of one or more joints of the midtarsal joint complex.

DESIGN

All prospectively followed patients with OA to one of or multiple joints of the midtarsal joint complex who were operated with a biological resurfacing arthroplasty with a fascia lata autograft (BioJoint procedure) were included. A total of 7 patients were included (5 males, 2 females), with a median age of 52 (interquartile range [IQR] 44-55) years. The primary outcome was the Numeric Rating Scale (NRS) for pain during walking 2 years postoperatively. Range of motion (ROM), revision rates, and complications were assessed. A postoperative MRI scan was performed to assess progression of OA, graft position and ingrowth, and the degree of bone marrow edema.

RESULTS

There was a 100% follow-up of the patients (median follow-up: 33 [IQR 26-33] months). The NRS during walking improved from 6 preoperatively to 2 at 2 years postoperatively (P < 0.05). There were no reoperations nor severe complications. The limitations in the ROM remained limited in the majority of the cases. MRI at 2 years of follow-up showed no progression of OA, reduced bone marrow edema, and no loosening of the grafts.

CONCLUSION

Biological resurfacing arthroplasty with a fascia lata autograft (BioJoint procedure) for OA to one or more joints in the midtarsal joint complex showed clinically relevant pain reduction during walking, improvement in clinical and radiological outcomes, and proved to be safe and durable.

Arthroscopic-Assisted Lower Trapezius Tendon Transfer Using a Fasciae Lata Autograft in Treatment of Posterior Superior Irreparable Rotator Cuff Tears in Lateral Decubitus Position

The optimal treatment for patients with posterior superior irreparable rotator cuff tears (PSIRCTs) is still a topic of ongoing debate. Lower trapezius tendon transfer is one of the effective surgical treatments for PSIRCTs in younger patients and elderly patients with high activity levels without arthritis. In this report, we describe an arthroscopic-assisted technique for lower trapezius transfer using a fascia lata autograft for patient with PSIRCTs in lateral decubitus position.

Reconstruction of chronic distal biceps ruptures by dermal matrix

OBJECTIVES

Distal biceps tear is uncommon, with well-recognized risk factors and typical clinical presentation. Delays in surgical treatment lead to several challenges, such as tendon retraction and tendon degeneration. We present a surgical technique using a sterilized acellular dermal matrix, which provides a solution for a challenging pathology.

MATERIAL AND METHODS

We present a detailed surgical technique of distal biceps reconstruction with acellular dermal matrix, performed in 4 patients, with an average time to diagnosis of 36 days (range, 28-45 days). Demographics, clinical data, range of motion and subjective satisfaction were collected.

RESULTS

At a mean follow-up of 18 months, all 4 patients showed full range of motion and strength, complete recovery and previous work resumed without pain. No complications appeared during this time.

CONCLUSIONS

Delayed distal biceps tear reconstruction by acellular dermal matrix showed promising results. Meticulous surgical technique using this matrix provided excellent reconstruction, with very solid anatomical repair and exceptionally good fixation, good clinical outcome and satisfied patients.

LEVEL OF EVIDENCE

IV.

Human Dermal Allograft Patch Augmentation of Degenerate Rotator Cuff Tendon Using a Single Lateral-Row Technique

The role of biological augmentation in arthroscopic rotator cuff repair surgery has increased over the years. It has shown favorable healing rates and functional outcomes. Patch augmentation is commonly applied in repairs of massively retracted cuff tears, full-thickness tears, revision repair, or open cuff surgery. There is a paucity of literature on the use of patch augmentation when dealing with a chronic degenerate tendon associated with small-sized cuff tears. In recent years, the resorbable bioinductive bovine collagen implant has gained popularity for its application in partial-thickness tears via an isolated bioinductive repair fashion, without traditional rotator cuff repair. These bioinductive implants, albeit promising in their biological properties for tendon repair, lack structural strength and do not confer similar biomechanical advantages as human dermal allograft. We share our surgical technique for an arthroscopic patch augmentation involving human dermal allograft, using a single-lateral row surgical fixation, to address a degenerate cuff tendon with small-sized rotator cuff tear. We believe that our use of a human dermal patch augmentation conferred increased biomechanical advantage and reduced costs while delivering favorable outcomes for patients in our value-driven care.

Reconstruction of the Acromioclavicular Joint Using a Double Augmentation With Hamstrings Tendon and Dermal Graft

The purpose of this article is to describe a technique to restore both vertical and horizontal stability using an augmentation of the acromioclavicular ligament complex (ACLC) and coracoclavicular (CC) ligaments with the combination of synthetic and biological support. Our technique introduces a modification in the surgical procedure for acromioclavicular (AC) joint dislocations; it provides the use of biological supplements not only during the repair of the CC ligaments but also when the ACLC is restored due to the use of a dermal patch as an augmentation allograft after the use of a horizontal cerclage. The main purpose of this technique is to replicate the anatomy and functionality of the native ligaments that stabilize the AC joint to improve both clinical and functional results.

Chronic Pectoralis Major Rupture Reconstruction With Interpositional Acellular Dermal Allograft

Background: Pectoralis major tendon (PMT) rupture commonly occurs in males 20 to 39 years of age. PMT rupture is most often associated with gym-based exercise, with attempted bench press being the most common causative event, but it is also associated with contact or impact sports. Delayed presentation, misdiagnoses, and chronic PMT rupture can result in a therapeutic dilemma.

Case Series: We present 2 cases of chronic PMT rupture that were operatively managed using acellular dermal allograft as an interposition graft. Patients’ final follow-ups were at 20 and 30 months, respectively. Strength in their pectoralis major muscle was well preserved on the contralateral side: 88% for patient 1 and 110% for patient 2.

Conclusion: Our reported technique using an interpositional acellular dermal allograft is a good option to treat chronic PMT rupture.

A New Treatment for the Reconstruction of the Medial Compartment of the Ankle: The Combined Use of Biological Materials

Fractures, especially if articular and periarticular, are frequently associated to functional and clinical disabling outcomes and chronic pain. In particular, the injuries with loss of bone, ligament, and/or tendon tissue in which the full recovery of the wound area is not obtained are the worst anatomical/pathological conditions to heal. In this study, three different biological materials were used as regenerative approaches to rebuild the medial malleolus fracture of the ankle in which loss of bone, ligament, and tendon tissue occur. In particular, the morselized human bone tissue was combined with the human dermis decellularized, both augmented with homologous platelet-rich plasma. The magnetic resonance imaging study with contrast at the follow-up showed a signal compatible with vascularization of the tissue without sign of degeneration. Our new regenerative approach in which different biological materials were combined together showed a good choice of treatment for the reconstruction of not repairable outcome of a fracture.

Comparison of biologic scaffolds for augmentation of partial rotator cuff tears in a canine model

BACKGROUND

This study was designed to test the hypothesis that biologic scaffold augmentation of articular-sided partial-thickness supraspinatus tendon tears would be associated with superior functional, imaging, biomechanical, and histologic properties compared with untreated tears in a preclinical canine model.

METHODS

With Institutional Animal Care and Use Committee approval, dogs (n = 16) underwent half-thickness resection of the articular portion of the supraspinatus tendon (SST). Defects were treated by débridement (DB) (n = 8) or scaffold augmentation on the bursal side using amnion matrix cord scaffold (AM) (n = 8), decellularized human dermal allograft (AF) (n = 8), or bovine collagen patch (RMP) (n = 8). Control dogs (n = 4; 8 normal shoulders) were included. Assessments included lameness, function, comfortable shoulder range of motion (CROM), pain, ultrasonography, magnetic resonance imaging (MRI), arthroscopy, gross examination, biomechanical testing, and histopathology.

RESULTS

At 3 months, CROM was significantly lower and pain significantly higher in DB compared with all other groups. At 6 months, CROM was significantly lower and pain significantly higher in RMP compared with AM and AF, and AM and AF showed significantly less thickening than DB and RMP. AF had the least severe MRI pathology and AM had significantly less MRI pathology than DB. AF SSTs and biceps tendons showed the least severe histopathology, and AM SSTs showed significantly less histopathology than DB and RMP SSTs.

CONCLUSION

Biologic scaffolds can be effective in augmenting healing of articular-sided partial-thickness SST tears when compared with débridement in a preclinical canine model. Decellularized human dermal allograft and amnion matrix cord may have advantages over the bovine collagen patch for use in this indication.

Acellular dermal matrix augmentation significantly increases ultimate load to failure of pectoralis major tendon repair: a biomechanical study

BACKGROUND

Biomechanical studies have demonstrated that standard pectoralis major tendon (PMT) repairs have inferior strength compared with native tendon.

HYPOTHESIS

Augmentation of PMT repair with an acellular dermal matrix (ADM) will increase the ultimate load to failure.

METHODS

Eighteen cadaveric specimens were allocated to 3 repair groups: standard repair (SR); augmented repair (AR) with ADM; and intact, native tendon (NT). Specimens were tested for cyclic elongation, linear stiffness, load to 5 mm displacement, maximum load to failure, and method of failure.

RESULTS

Maximum load to failure in AR (1450 ± 295 N) was significantly higher than SR (921 ± 159 N; P = .0042) and equivalent to NT (1289 ± 240 N; P = .49). NT required the highest load to displace 5 mm (709 ± 202 N), which was higher than AR (346 ± 95 N; P < .001) and SR (375 ± 55; P = .0015). NT stiffness (125 ± 42 N/mm) was greater than the AR (69 ± 19 N/mm; P = .0073) or SR (75 ± 11 N/mm; P = .015). The mode of failure for SR was suture pullout from the PMT as opposed to button pullout from the humerus (fracture) for AR.

CONCLUSION

ADM augmentation of PMT repair significantly increases ultimate load to failure.

Rationale for Biologic Augmentation of Rotator Cuff Repairs

The structural integrity of rotator cuff repair (RCR) has been a primary focus for shoulder surgeons seeking long-term clinical and functional success. Improvements in surgical techniques have allowed for superior initial biomechanical fixation. However, tendon healing remains a significant clinical problem even after rigid time-zero repair. The lack of long-term healing has led to increased interest in biologic augmentation to improve tendon-to-bone healing. This interest has led to a rise in the investigation of small molecular therapies, cell-based strategies, and tissue-derived treatments offering surgeons a new therapeutic toolbox for potentially improving RCR long-term outcomes. However, the delivery, efficacy, and safety of these treatments remain under investigation. Additional well-designed, high-level studies are of paramount importance in creating evidence-based guidelines for the implementation of new biologic solutions. This review article discusses the current preclinical, translational, and clinical experience with and rationale for biologic augmentation in RCR.

Arthroscopic Rotator Cuff Repair With Allograft Augmentation: Making It Simple

Rotator cuff tears are increasing in frequency in the aging population and are a common issue seen by orthopaedic surgeons. In patients with large, multi-tendon rotator cuff tears or retears, treatment can be challenging. Failure rates of up to 90% have been reported for rotator cuff repair (RCR) of large, multi-tendon tears. Biological augmentation has been an area of interest because of the distinctly different biology of the repaired tendon compared with the native tendon. These biological differences affect the ultimate tensile properties of the repair and may contribute to gap formation and the high failure rate of repairs. RCR with allograft augmentation is a technique that shows potential benefit to healing and preventing retears. Arthroscopic augmentation of RCRs can be challenging. The technique described in this Technical Note illustrates a simple and easily reproducible method for augmenting RCRs with human acellular dermal allograft.

Failure of Dermal Allograft Repair of Massive Rotator Cuff Tears in Magnetic Resonance Imaging and Clinical Assessment

Background

Massive retracted rotator cuff tears represent a therapeutic dilemma, particularly in the young and middle-aged patients who are not appropriate for a reverse total shoulder replacement. Interposition grafting using human dermal allograft offers an alternative treatment.

Methods

A retrospective review of all patients who underwent interposition grafting using human dermal allograft between December 2013 and May 2015 for massive rotator cuff tears at our tertiary referral center was performed. Preoperative and 6 month postoperative magnetic resonance imaging (MRI) assessments were performed in all patients, with postoperative graft integrity being the primary outcome measure. Clinical evaluation was performed using the Oxford shoulder score, Constant score, and Disabilities of the Arm, Shoulder and Hand (DASH) score.

Results

The mean age at the time of follow-up was 54 years. On MRI, 84% of grafts were seen to have failed at 6 months. Strength was grossly reduced on the operative side when supraspinatus and subscapularis were tested; despite this, Constant score (mean, 48.2) was comparable to that in the previous reports. DASH and Oxford scores were a mean of 24.94 and 37.16, respectively.

Conclusions

Based on these results, in particular the MRI findings, we cannot advocate the use of dermal allograft as an interposition graft for the repair of massive rotator cuff tears.

Achilles Tendon Augmented Repair Using Human Acellular Dermal Matrix: A Case Series

Achilles tendon ruptures are common in the general population, especially among members of the older demographic occasionally active in sports. Operative treatments provide a lower incidence of rerupture than do nonoperative treatments, although surgical complications remain a concern. The use of a human acellular dermal matrix to augment Achilles tendon repair might reduce the incidence of complications. In the present case series, we describe the outcomes of 9 patients who underwent Achilles tendon repair with acellular dermal matrix augmentation. Functional outcomes were evaluated using the Foot Function Index-Revised long form, and the clinical results were recorded. After a mean average follow-up period of 14.4 (range 12.0 to 20.0) months, the mean Foot Function Index-Revised long form score was 33.0% ± 4.2%. No cases of rerupture or complications that required additional treatment occurred during the observation period. The outcomes we have presented support further evaluation beyond this case series for using a human acellular dermal matrix to augment Achilles tendon repairs.

Latissimus Dorsi Tendon Transfer with GraftJacket® Augmentation to Increase Tendon Length for an Irreparable Rotator Cuff Tear

Massive irreparable rotator cuff tears can be reconstructed with latissimus dorsi tendon transfers (LDTT). Although uncommon, the natural length of the latissimus dorsi tendon (LDT) could be insufficient for transfer even after adequate soft tissue releases. Descriptions of cases where grafts were needed to lengthen the LDT are therefore rare. We located only two reports of the use of an acellular dermal matrix to increase effective tendon length in tendon transfers about the shoulder: (1) GraftJacket patch for a pectoralis major tendon reconstruction and (2) ArthroFlex® patch for LDTT. Both of these brands of allograft patches are obtained from human cadavers. These products are usually used to cover soft tissue repairs and offer supplemental support rather than for increasing tendon length. Extending the LDTT with GraftJacket to achieve adequate length, to our knowledge, has not been reported in the literature. We report the case of a 50-year-old male who had a massive, irreparable left shoulder rotator cuff tear that was reconstructed with a LDTT. The natural length of his LDT was insufficient for transfer. This unexpected situation was rectified by sewing two patches of GraftJacket to the LDT. The patient had greatly improved shoulder function at two-year follow-up.

Cadaveric Study of Insertional Anatomy of Distal Biceps Tendon and its Relationship to the Dynamic Proximal Radioulnar Space

PURPOSE

To quantify and assess the relationship between the insertional dimensions of the distal biceps tendon (DBT) and radioulnar space (RUS) in 3 rotational positions. We hypothesized that in all positions RUS would be adequate for the DBT and would remain adequate even after an incremental increase (1 to 3 mm) in tendon thickness.

METHODS

Eleven fresh-frozen cadaveric elbows were dissected; DBT dimensions and bicipital tuberosity measurements were performed and insertional footprints were quantified using a distal biceps footprint index. The RUS was measured at 3 levels of the bicipital tuberosity and in 3 positions of forearm rotation. We performed statistical analysis to analyze differences in RUS (positional and inter-level). In addition, significant differences between DBT thickness (native and incremental) and RUS were analyzed to identify potential sites of radioulnar impingement.

RESULTS

The DBT had a mean length of 92 mm; thickness ranged from 2.9 to 6.1 mm. Three variations in DBT insertional footprint were observed and quantified. The RUS linear distance reduced significantly from a supinated to a pronated position at each of 3 bicipital tuberosity levels; the reduction was statistically significant at the lower tuberosity level (45%). Pronation RUS distance was adequate for native DBT thickness and was significantly less when DBT thickness increased by 2 and 3 mm.

CONCLUSIONS

Radioulnar space reduces significantly from the supinated to the pronated position and is most evident in the lower aspect of the tuberosity. In addition, the RUS in pronation is inadequate for incremental increases in DBT thickness.

CLINICAL RELEVANCE

Postoperative DBT impingement in the RUS may be prevented by avoiding techniques that increase the thickness of the tendon and by using a reattachment site at the proximal aspect of the tuberosity.

Use of grafts in rotator cuff re-rupture

INTRODUCTION AND OBJECTIVES

Rotator cuff re-ruptures appear in 38-65% of cases. In order to reduce this rate, many studies have been performed using different types of biomaterial for purely mechanical aims (re-inforce the suture) and/or biological agents (growth factor transporterts). The aim of this study is to review 22 cases treated with xenografts and analyse various current alternatives.

MATERIALS AND METHODS

A descriptive and retrospective study was conducted using the variables of age, sex, laterality, time of surgery, involvement in MRI, number of anchors, and final mobility results on the Constant and the University of California Los Angeles (UCLA) validated scales.

RESULTS

The study included 22 patients, with a mean age of 51.7±4.6 years. A mean of 2 anchors were used and 13 patients were treated with a porcine intestinal submucosa implant, 6 with equine pericardium, and 3 with porcine dermis. Final results were: 37.6±13 points for the Constant test, and 16.9±3.9 points on the UCLA scale. The follow up was 36±10.2 months.

CONCLUSIONS

In our experience, xenografts could provide good functional results and they would be a surgical alternative to tendon transfers in cases of massive tears. Further studies should be conducted with other biomaterials.

Ex Vivo Dermis Mechanical Behavior in Relation to Decellularization Treatment Length

Background:

The dermis is a commonly used source tissue for biologic scaffolds; all cellular and nuclear materials need to be removed to limit the inflammatory immune response by the host organism. The decellularization is critical because it must preserve the structural integrity of the extracellular matrix. This work has analyzed a decellularization procedure commonly followed for the dermal tissue that is a chemical treatment with sodium hydroxide. The goal of this work is to identify the optimal treatment length on the basis of structural properties.

Methods:

Tensile tests have been performed on the native tissue and on tissues decellularized for 1-7 weeks in sodium hydroxide. The collected data have been analyzed through Tukey-Kramer test to assess if the mechanical properties (ultimate tensile stress and elastic modulus) of decellularized tissues were significantly different from the properties of the native tissue. These tests have been performed on specimens cut along two orthogonal directions (parallel and perpendicular to Langer’s lines).

Results:

The decellularization treatment performed with sodium hydroxide in general weakens the tissue: both the ultimate stress and the elastic modulus get lower. The structural properties along Langer lines orientation are more strongly impacted, while the structural properties orthogonal to Langer lines can be preserved with an optimal duration of the decellularization treatment that is 5-6 weeks.

Conclusion:

The duration of the decellularization treatment is critical not only to reach a complete decellularization, but also to preserve the mechanical properties of the tissue; 5-6 week treatment performed with sodium hydroxide allows preserving the mechanical properties of the native tissue perpendicularly to Langer lines orientation, and minimizing the impact of the decellularization process on the mechanical properties along the Langer lines orientation.