Role of vascularity for successful bone formation and repair.

Tissue engineering has been touted as the solution to regenerate tissue in patients. Yet current strategies for orthopedic application are limited because of the inability to successfully manage critical sized defects without a working vascular system. Bone grafts are commonly used in critical sized defects to fill the gap in missing bone tissue. Proper vasculature is vital to the success of these grafts to promote bone growth. The aim of this review is to describe the contribution of tissues surrounding critical sized defects, focusing in particular on the progenitor cell influx and factors contributing to neovascularization. An overview of clinical techniques to visualize patient vascular supply and evaluation of clinical techniques to increase blood flow to the critical defect site illustrates the current efforts of surgical intervention to promote proper bone formation. The opportunity and need lies in the development of tissue engineered bone grafts that can use and enhance available vascular supplies.

The effectiveness of cervical mucus electrical impedance compared to basal body temperature to determine fertility window.

BACKGROUND: Serial serum hormone measurements and transvaginal ultrasound are reliable measures to predict ovulation. These measures are inconvenient and expensive therefore, basal body temperature charting (BBT) and urine ovulation predictor kits (OPK) for luteinizing hormone are often used to determine the 6-day fertile window. However, BBT does not clearly change until 1-2 days after ovulation. Additionally, while OPK can indicate positivity prior to ovulation, false readings are common. A novel alternative approach involves measuring electrolyte trends in cervical mucus using electrical impedance spectroscopy. Cervical mucus electrolyte measurements are associated with hormone level changes during the menstrual cycle. The purpose of this study was to compare the effectiveness of cervical mucus electrical impedance and basal body temperature. We sought to determine if cervical mucus electrolyte measurements provided improved detection of the ovulation day and therefore, improve fertility timing for women. METHODS: 14 healthy women between 18 and 44 years of age with normal menstrual cycles were enrolled in the Observational Study. Participants measured BBT and cervical mucus electrical impedance daily for 3 menstrual cycles using Kegg (Lady Technologies Inc. San Francisco, California, USA). Ovulation date for each cycle was confirmed by measuring hormone levels in urine and serum, and by vaginal ultrasound. RESULTS: Electrical impedance was significantly different between the follicular phase versus ovulatory date (p = 0.007) and between the luteal phase versus the ovulatory date (p = 0.007). A significant difference in the rate of change of cervical impedance measurements in the pre-ovulatory follicular phase was found compared to BBT (p = 0.0225). The sensitivity (+ 7.14%), specificity (+ 20.35%), and accuracy (+ 17.59) to determine the 1-day fertility window was significantly higher using cervical mucus impedance compared to BBT. CONCLUSIONS: BBT is considered unreliable for evaluating ovulatory function. Cervical mucus electrical impedance offers a novel measure of electrolyte changes associated with hormone levels. We report that pre-ovulatory electrical impedance patterns demonstrated higher sensitivity, specificity, and accuracy for determining the fertility window when compared to BBT. These findings suggest that changes in electrical impedance may provide an accurate method for predicting ovulation and for measuring ovulatory function.

Strong Correlation Between Femoral Condyle Radius of Curvature and Anterior-Posterior Length: Implications for Osteochondral Allograft Matching.

BACKGROUND: The radius of curvature (ROC) of the femoral condyle is a factor in potential cartilage incongruities following osteochondral allograft (OCA) transplantation. Accurate restoration of the chondral surface may be achievable by using "best-fit" donor-recipient matching based on linear femorotibial dimensions, such as the femoral condyle anterior-posterior length (APL), femoral condyle width (lateral-medial length, LML), femoral hemicondyle width (HCW), and tibial plateau width (TPW), particularly if they correlate well with the ROC. This study aimed to investigate the correlative relationship between femorotibial dimensions and the ROC. METHODS: Computed tomography (CT) scans from 49 patients (31 men 28 ± 10 years old and 18 women 27 ± 6 years old) were analyzed. Axial images were used for APL and LML measurements, while coronal images were used for HCW and TPW. True sagittal images of the medial femoral condyle (MFC) and lateral femoral condyle (LFC) were used to calculate their individual ROCs by determining the best-fit circles along the condylar surface. Linear regression models were used to determine the relationship between the femorotibial dimensions and ROC. Measurements were repeated for a randomly selected subset of the data, and intraclass correlation coefficients (ICCs) were calculated to investigate intra- and interobserver reliability. RESULTS: All femorotibial dimensions showed significant correlations with the MFC and LFC ROCs (p < 0.01). The ROC correlations with femorotibial dimensions were found to be in the following descending order: APL (R2 ≥ 0.83), LML (R2 ≥ 0.52), TPW (R2 ≥ 0.36), and HCW (R2 ≥ 0.27). The intra- and interobserver reliabilities for the APL (ICC > 0.98) and ROC (ICC > 0.94) were excellent. CONCLUSIONS: The ROC was strongly correlated with the APL of the MFC and LFC. Donor-recipient APL matching in OCA transplantation may provide a level of matching similar to that achievable by direct ROC measurements. CLINICAL RELEVANCE: Determining the most predictive femorotibial dimension for ROC restoration in the OCA matching process may improve clinical outcomes, particularly for patients with large osteochondral lesions.

Elevated Lipid Metabolites in Stored Clinical OCA Media Correlate With Chondrocyte Death.

BACKGROUND: A major limitation of osteochondral allografts (OCA) is the deterioration of cartilage health associated with cell death during prolonged storage. However, little is known about the mechanisms that contribute to chondrocyte death during storage. PURPOSE/HYPOTHESIS: This study aimed to determine whether bioactive lipid metabolites accumulate in the storage media of OCA and whether they are associated with a loss of chondrocyte viability during prolonged storage. It was hypothesized that free fatty acids (FFAs) would accumulate over time in the storage media of OCA and adversely affect cartilage health during storage. STUDY DESIGN: Controlled laboratory study. METHODS: A group of 21 (n = 6-8 OCA/treatment group) fresh human hemicondylar OCA tissues and media were analyzed after 7, 28, and 68 days of prolonged cold (4°C) storage. Targeted mass spectrometry analysis was used to quantify bioactive FFAs, as well as primary (lipid hydroperoxide [ROOH]) and secondary (malondialdehyde) lipid oxidation products. Chondrocyte viability was measured using a fluorescence-based live/dead assay and confocal microscopy. RESULTS: The concentration of all targeted fatty acid metabolites in storage media was significantly increased with increased cold storage time (P < .05). ROOH was significantly higher on day 28 of cold storage. No difference in secondary ROOH products in storage media was observed. Chondrocyte viability significantly declined in both the en face and the vertical cross-sectional analysis with increased cold storage time and inversely correlated with fatty acid metabolites (P < .05). CONCLUSION: It is well established that elevated levels of certain FFAs and lipid oxidation products can alter cell function and cause cell death via lipotoxicity and other mechanisms. This work is the first to identify elevated levels of FFA metabolites and primary oxidation lipid products in the storage media from clinical OCA. The concentrations of FFA metabolites were measured at levels (>100 µM) known to induce cell death and were directly correlated with chondrocyte viability. CLINICAL RELEVANCE: These findings provide important targets for understanding why cartilage health declines during cold storage, which can be used to optimize media formulations and improve graft health.

Avascular necrosis of the proximal humerus: a novel indication for the use of osteochondral allograft transplantation in the shoulder: Case report.

Osteochondral allograft (OCA) transplantation is an increasingly available biologic treatment option for a range of intraarticular aetiologies. To our knowledge, no prior publication has documented the use of this technology to treat a lesion of the proximal humerus secondary to avascular necrosis (AVN). We describe our experience treating a 42-year-old female executive with idiopathic AVN of the proximal humerus with a fresh osteochondral allograft. Computed tomography (CT) at 3 months post-op showed full bony incorporation and a restored native joint contour. Over the initial 7 months post-operatively, she reported continued improvements in pain and function as measured by quick Disabilities of the Arm, Shoulder, and Hand (DASH) scores. She was discharged from physical therapy after 6 months, reporting no rest pain, full active and passive range of motion, and unrestricted occupational and recreational activity.

Osteochondral Allograft Transplantation in the Shoulder: A Systematic Review of Indications and Outcomes.

OBJECTIVE: To collate current literature pertaining to the published reports of indications for, and outcomes of, osteochondral allograft (OCA) transplantations in the shoulder so as to guide surgeons in the management of various etiologies of osteochondral lesions in this joint. DESIGN: A systematic review of the current literature was performed in February 2022 in the PubMed, Cochrane, and EMBASE databases using specific search terms and predetermined inclusion/exclusion criteria. RESULTS: One-hundred-twenty-three articles were initially identified, 30 full-text articles were assessed for eligibility, and 17 articles met inclusion criteria. Data were collected for study characteristics, etiology, lesion size/location, intervention/type of graft used, follow-up, and outcomes. In total, 83 shoulders were included (n = 83) in the review with an average follow-up of 45.7 months. Nine specific indications for OCA transplantation in the shoulder included: reverse Hill-Sachs lesions (33), Hill-Sachs lesions (22), pain pump chondrolysis (10), recurrent shoulder instability (7), osteoarthritis/degenerative changes (5), radiofrequency chondrolysis (2), prominent suture anchors (2), glenoid lesion (1), and osteochondritis dissecans (1). Seventeen patients had concomitant surgeries and two patients were lost to follow-up. Of the total 83 shoulders, 68 had favorable outcomes and 13 had unfavorable outcomes as determined by graft incorporation, pain scores, functionality/ROM, patient-reported satisfaction, and/or requirement for revision/arthroplasty. Of the 13 with unfavorable outcomes, a disproportionate number had concomitant surgeries and/or were performed for pain pump chondrolysis (6). CONCLUSIONS: The use of OCAs appears to be a viable option for a variety of difficult-to-treat shoulder pathologies, particularly those characterized by isolated osteochondral injuries.

Meniscus Size Differs Between Patient and Donor Populations for Meniscus Allograft Transplantation.

Purpose: To determine the extent of variability in meniscus size and anthropometric data between donors (supply) and patients (demand), to evaluate potential factors that may contribute to size discrepancies, and to determine whether the discrepancies lead to longer patient wait times. Methods: Lateral and medial meniscal measurements, anthropometric data, and time to match a donor graft were extracted from a tissue supplier database. The frequency and distribution of meniscus size were analyzed. Body mass index (BMI), relative meniscus area, body mass to meniscus area index, and height to meniscus area index were compared between patient and donor pools via χ2 tests and independent samples t-test. The effect of size on time to match was analyzed using analysis of variance and post-hoc Tukey test. Results: The lateral meniscus patient population showed a greater frequency of larger size requirements compared to the donor population (P < .001) and the medial meniscus patient population showed a higher frequency of smaller meniscus size requirements (P < .001). The medial meniscus analysis showed significantly smaller meniscus areas (P < .001) in the patient population contributing to the observed trend of an increased body mass to meniscus area index and height to meniscus area index. The time to match a donor meniscus was affected by the patient meniscus size. Conclusions: This analysis demonstrates variations in frequency of meniscus sizes between donor and patient populations. This variation is attributed to differences in anthropometric data between patient and donor populations. This work identifies a mismatch between demand and supply for certain patient sizes contributing to longer times to match. Clinical Relevance: This work associated donor and patient mismatches with longer wait times. This can be useful for patient counseling as well as provide a framework to determine whether there are solutions within the current meniscus donor pool that can be used to meet this clinical need.

Fresh Osteochondral and Chondral Allograft Preservation and Storage Media: A Systematic Review of the Literature.

BACKGROUND: Storage procedures and parameters have a significant influence on the health of fresh osteochondral allograft (OCA) cartilage. To date, there is a lack of agreement on the optimal storage conditions for OCAs. PURPOSE: To systematically review the literature on (1) experimental designs and reporting of key variables of ex vivo (laboratory) studies, (2) the effects of various storage solutions and conditions on cartilage health ex vivo, and (3) in vivo animal studies and human clinical studies evaluating the effect of fresh OCA storage on osteochondral repair and outcomes. STUDY DESIGN: Systematic review; Level of evidence, 5. METHODS: A systematic review was performed using the PubMed, Embase, and Cochrane databases. The inclusion criteria were laboratory studies (ex vivo) reporting cartilage health outcomes after prolonged storage (>3 days) of fresh osteochondral or chondral tissue explants and animal studies (in vivo) reporting outcomes of fresh OCA. The inclusion criteria for clinical studies were studies (>5 patients) that analyzed the relationship of storage time or chondrocyte viability at time of implantation to patient outcomes. Frozen, cryopreserved, decellularized, synthetic, or tissue-engineered grafts were excluded. RESULTS: A total of 55 peer-reviewed articles met the inclusion criteria. Ex vivo studies reported a spectrum of tissue sources and storage solutions and conditions, although the majority of studies lacked complete reporting of key variables, including storage solution formula and environmental conditions. The effect of various conditions (eg, temperature) and storage solutions on cartilage health were inconsistent. Although 60% of animal models suggest that storage time may influence outcomes and 80% indicate inferior outcomes with frozen OCA as compared with fresh OCA, 75% of clinical studies report no correlation between storage time and outcomes. CONCLUSION: Given the variability in experimental designs and lack of reporting across studies, it is still not possible to determine optimal storage conditions, although animal studies suggest that storage time and chondrocyte viability influence osteochondral repair outcomes. A list of recommendations was developed to encourage reporting of key variables, such as media formulation, environmental factors, and methodologies used. High-quality clinical data are needed to investigate the effects of storage and graft health on outcomes.

Variability in Private Payer Medical Policies for Osteochondral Allograft Transplantation Demonstrates the Absence of Standardization in Medical Criteria Between Payers.

Purpose: To define the criteria for coverage for a cartilage restoration procedure and osteochondral allograft (OCA) transplantation and to investigate coverage for OCA procedures among private payer medical policies. Methods: A systematic search of private payer websites was conducted to identify publicly available 2018 OCA medical policies. Medical criteria related to patient demographics, defect characteristics, and previous treatment were analyzed. Trends in coverage for treatment of talus and patella and the extent of restrictiveness of medical policies were evaluated from 2016 to 2018. The extent of restrictiveness of a policy was defined by number of medical criteria established by payer policies. Policies with >5, 3-5, and <3 specified criteria for OCAs were considered strongly, moderately, and weakly restrictive, respectively. Results: In total, 49 private payer medical policies for OCA transplantation were identified. Extracted criteria varied greatly between medical policies. Ten different defect size ranges were reported across payer policies. Criteria for patient body mass index was specified in 63% of policies. Criteria for failed arthroscopic or traditional surgical procedure were identified in 20% of the policies. More than one half of policies (51%) specified knee defect location to load-bearing surfaces. Analysis of trends in positive coverage statements and restrictiveness showed an increase from 4.7% in 2016 to 39.5% for talus, 4.7% to 7.0% for patella, and a slight shift (4.7% of payers) toward weakly restrictive medical policies. Conclusions: This study demonstrates wide variability and inconsistencies in published criteria among OCA medical policies. Clinical Relevance: This study informs clinicians of the current state of coverage for OCA transplantation, providing insights into the variability of payer policies and potential impact.

Inconsistent Reporting of Preauthorization Medical Criteria for Osteochondral Allograft Transplantation Surgery.

BACKGROUND: Although osteochondral allograft (OCA) transplantation has been a standard treatment for patients with osteochondral lesions, there is a disagreement in commercial payers' medical criteria regarding the definition of medical suitability and thus authorization for OCA transplantation. The primary goal of this study was to understand where consensus between a committee of experienced cartilage restoration surgeon scientists and payer policies existed and where there was significant disagreement. METHODS: U.S. private payers were identified by reviewing health insurance market research literature. Medical criteria were then obtained from publicly available payer medical polices. A literature review was conducted to identify supporting evidence for consensus statements based on private payer medical criteria. The MOCA (Metrics of Osteochondral Allograft) Committee, 30 experienced surgeons and subject-matter experts in OCA transplantation, used a Likert scale of 1 (strongly disagree) to 5 (strongly agree) to rank each statement. The extent of agreement and disagreement among participants was measured for each statement. Consensus was defined as agreement or disagreement of >75%. RESULTS: Fifty-seven statements regarding relevant medical criteria for OCA transplantation were included in the survey. All 30 MOCA Committee members completed the survey (100% response rate). Over half of the statements (52.6%) did not reach consensus. Of the remaining 27 statements that reached consensus, respondents agreed or strongly agreed with 16 statements, and disagreed or strongly disagreed with 11 statements. Inconsistent voting was observed for statements related to osteoarthritis, inflammation, and degenerative changes. CONCLUSIONS: Commercial payers are not consistent in the medical criteria used to define patient eligibility for authorization of OCA transplantation. In contrast, an expert panel of cartilage surgeons reached a consensus that OCA transplantation was clearly suitable for a variety of specific indications. This study demonstrates the need to standardize medical criteria for cartilage restoration based on the most current literature, as well as in conjunction with experienced cartilage restoration experts. LEVEL OF EVIDENCE: Therapeutic Level V . See Instructions for Authors for a complete description of levels of evidence.

Surface topography as a tool to detect early changes in a posttraumatic equine model of osteoarthritis.

The equine model of posttraumatic osteoarthritis (OA) mimics certain aspects of the naturally occurring disease, both in horses and humans. The objective of this study was to assess articular cartilage degeneration in a posttraumatic OA model using the established macroscopic and microscopic scoring systems and compare them with a novel surface topography analysis. OA was induced in the carpal joint of 15 (n = 15) mixed breed horses. Surface changes on the articular cartilage were characterized using osteochondral blocks from the third carpal bone (C3) and radial carpal bone using surface topography, standard histological grading, and gross evaluation of the joints. Significant differences were observed between OA and non-OA joints for gross evaluation scores. Microscopic scores of hematoxylin and eosin and Safranin O and Fast Green-stained sections demonstrated no differences between OA and non-OA joints. However, articular cartilage from the induced OA joint had significantly greater surface topography measurements compared with the sham treatment group, consistent with the changes seen on gross evaluation of joints. No significant correlations were noted between surface roughness measurements, histological assessment, and gross evaluation scores. The results suggest that surface topography analysis may provide a reliable objective approach to assess early changes in the cartilage surface in OA.

Metrics of OsteoChondral Allografts (MOCA) Group Consensus Statements on the Use of Viable Osteochondral Allograft.

BACKGROUND: Osteochondral allograft (OCA) transplantation has evolved into a first-line treatment for large chondral and osteochondral defects, aided by advancements in storage protocols and a growing body of clinical evidence supporting successful clinical outcomes and long-term survivorship. Despite the body of literature supporting OCAs, there still remains controversy and debate in the surgical application of OCA, especially where high-level evidence is lacking. PURPOSE: To develop consensus among an expert group with extensive clinical and scientific experience in OCA, addressing controversies in the treatment of chondral and osteochondral defects with OCA transplantation. STUDY DESIGN: Consensus statement. METHODS: A focus group of clinical experts on OCA cartilage restoration participated in a 3-round modified Delphi process to generate a list of statements and establish consensus. Questions and statements were initially developed on specific topics that lack scientific evidence and lead to debate and controversy in the clinical community. In-person discussion occurred where statements were not agreed on after 2 rounds of voting. After final voting, the percentage of agreement and level of consensus were characterized. A systematic literature review was performed, and the level of evidence and grade were established for each statement. RESULTS: Seventeen statements spanning surgical technique, graft matching, indications, and rehabilitation reached consensus after the final round of voting. Of the 17 statements that reached consensus, 11 received unanimous (100%) agreement, and 6 received strong (80%-99%) agreement. CONCLUSION: The outcomes of this study led to the establishment of consensus statements that provide guidance on surgical and perioperative management of OCAs. The findings also provided insights on topics requiring more research or high-quality studies to further establish consensus and provide stronger evidence.

Designer Stem Cells: Genome Engineering and the Next Generation of Cell-Based Therapies.

Stem cells provide tremendous promise for the development of new therapeutic approaches for musculoskeletal conditions. In addition to their multipotency, certain types of stem cells exhibit immunomodulatory effects that can mitigate inflammation and enhance tissue repair. However, the translation of stem cell therapies to clinical practice has proven difficult due to challenges in intradonor and interdonor variability, engraftment, variability in recipient microenvironment and patient indications, and limited therapeutic biological activity. In this regard, the success of stem cell-based therapies may benefit from cellular engineering approaches to enhance factors such as purification, homing and cell survival, trophic effects, or immunomodulatory signaling. By combining recent advances in gene editing, synthetic biology, and tissue engineering, the potential exists to create new classes of "designer" cells that have prescribed cell-surface molecules and receptors as well as synthetic gene circuits that provide for autoregulated drug delivery or enhanced tissue repair. Published by Wiley Periodicals, Inc. J Orthop Res 37:1287-1293, 2019.

Characterization and Separation of Cancer Cells with a Wicking Fiber Device.

Current cancer diagnostic methods lack the ability to quickly, simply, efficiently, and inexpensively screen cancer cells from a mixed population of cancer and normal cells. Methods based on biomarkers are unreliable due to complexity of cancer cells, plasticity of markers, and lack of common tumorigenic markers. Diagnostics are time intensive, require multiple tests, and provide limited information. In this study, we developed a novel wicking fiber device that separates cancer and normal cell types. To the best of our knowledge, no previous work has used vertical wicking of cells through fibers to identify and isolate cancer cells. The device separated mouse mammary tumor cells from a cellular mixture containing normal mouse mammary cells. Further investigation showed the device separated and isolated human cancer cells from a heterogeneous mixture of normal and cancerous human cells. We report a simple, inexpensive, and rapid technique that has potential to identify and isolate cancer cells from large volumes of liquid samples that can be translated to on-site clinic diagnosis.

The effect of wicking fibres in tissue-engineered bone scaffolds.

The major limitation of large tissue-engineered constructs used for bone regeneration is the lack of vasculature and, therefore, lack of transport of essential nutrients, chemical factors and progenitor cells. Research approaches to improve the transport properties of large scaffolds focus on using angiogenic factors and vasculogenic cells to create new vasculature; however, the slow rate of vessel formation and reliance on vessel self-assembly in these approaches is problematic. In this study, a novel approach has been proposed, using proprietary engineered 'wicking' fibres of non-circular cross-section that provide highly efficient transport for fluid and cells. The effect of wicking fibres on the movement of fluorescein isothiocyanate (FITC)-conjugated protein in a three-dimensional (3D) hydrogel system was analysed. The results indicated that the rate of diffusion of the fluorescent protein was greatly enhanced in hydrogels that contained wicking fibres in comparison to those that did not. The movement of progenitor cells along wicking fibres and round fibres was assessed. This study demonstrated that wicking fibres enhance the movement of critical growth factors and progenitor cells central for bone regeneration. The results suggested that the incorporation of wicking fibres into large tissue-engineered constructs may improve the transport of growth factors and progenitor cells essential for bone formation.