Fresh Osteochondral Allograft Research Articles

Participation in Sports or Recreational Activities After Osteochondral Allograft Transplantation of the Talus

Background: Fresh osteochondral allograft (OCA) transplantation is a viable treatment option for osteochondral defects of the talus. However, sufficient data are not available on patients’ participation in sports or recreational activities after the procedure. Purpose: To assess whether patients undergoing OCA transplantation of the talus participated in sports or recreational activities postoperatively. Study Design: Case series; level of evidence, 4. Methods: A total of 36 ankles in 34 patients underwent OCA transplantation of the talus. At a mean follow-up of 9.2 years, information on participation in sports or recreational activities pre- and postoperatively was obtained, as well as postoperative pain, function, and satisfaction. Results: The mean age at the time of surgery was 36.1 years (range, 20.5-57.7 years), and 50% of patients were men. The mean graft size was 3.6 cm2 (range, 1-7.2 cm2) or 41.1% of the talar dome. Before the injury, 63.9% of patients (23/36 ankles) reported being highly competitive athletes or well trained and frequently sporting; 36.1% of patients (13/36 ankles) reported sometimes sporting or were nonsporting. Also, 66.7% of patients (24/36 ankles) were able to participate in sports or recreational activities after OCA transplantation and 50% (18/36 ankles) were still participating in sports or recreational activities at the latest follow-up. In a subset of well-trained or highly competitive athletes, 73.9% (17/23 ankles) were able to return to sports or recreational activities at any point after OCA transplantation, and 65.2% (15/23 ankles) were still participating at the latest follow-up. Further surgery occurred in 16.7% of patients (6/36 ankles). Graft survivorship was 94.3% at 5 years and 85.3% at 10 years. There was a significant improvement in the mean Olerud-Molander Ankle Scores, and the mean Foot and Ankle Ability Measure scores were high postoperatively. Moreover, 79.4% of patients (27/34 ankles) were either satisfied or extremely satisfied with the allograft surgery. Conclusion: Fresh OCA transplantation is a reasonable surgical option for osteochondral defects of the talus for young, active patients who have failed previous operative management or have massive defects.

Fresh Osteochondral Allograft to Medial Femoral Condyle With Proximal Tibial Opening Wedge Osteotomy

Background: Contributors to knee degeneration include mechanical axis malalignment, patellar maltracking, meniscal deficiency, and tibiofemoral instability. Full-thickness osteochondral defects in young, active patients can lead to significant pain and instability. The gold standard treatment for large (>2 cm2) osteochondral defects is an osteochondral allograft (OCA) which addresses the pathologic articular cartilage loss and underlying bone deficiency. While biologic failure of fresh OCAs is reported, the majority of early failures are attributed to unaddressed mechanical malalignment in the coronal plane. Proximal tibial osteotomy (PTO) corrects malalignment thereby unloading the affected medial compartment and the newly placed OCA, improving long-term survivability. Indications: OCAs are indicated for isolated osteochondral defects and lesions in active young patients. PTO is indicated for patients with varus malalignment who risk potential graft failure of the affected medial compartment. Technique Description: The articular cartilage defect is identified, and a guide pin is drilled in the center. The defect is templated and scored around the margins. A reamer is used to drill to a total depth of 7 to 8 mm. The recipient site is then dilated for graft insertion. On the donor graft, the harvest site is outlined and drilled to the proper diameter. Careful measurement is utilized to ensure graft depth measurements match the recipient site. Once sized, the graft is tapped into place obtaining an anatomic fit along its entire periphery. The osteotomy is performed by using guide pins to delineate the plane cutting the tibia. Fluoroscopy confirmed the osteotomy site and angle. A spacing plate was securely inserted with screws, with placement confirmed by fluoroscopy. Results: Fresh OCAs can restore osteochondral defects. PTO corrects malalignment and unloads the affected medial compartment, decreasing the risk of revision graft failure or total knee arthroplasty. Discussion: Clinical and biomechanical studies that compared isolated and concomitant procedures demonstrated that OCA with PTOs had significantly greater survival rates. Significant malalignment increases the risk of graft failure. It remains unclear whether concomitant osteotomy with osteoarticular allografts leads to increased complication risk; inherent risks remain associated with individual procedures. In adolescents, simultaneous corrective osteotomy along with fresh OCA may delay arthroplasty and associated ambulatory restrictions. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Osteochondral Allograft Transplantation in the Knee

Osteochondral injuries of the knee can be a frequent source of debilitating pain and dysfunction. Significant chondral (>1.5-2 cm2) lesions of the femoral condyles can be especially difficult to manage with nonsurgical measures. Fresh osteochondral allograft (OCA) transplantation has been shown to be a reliable surgical procedure to manage a wide array of high-grade focal chondral lesions, with or without subchondral bone involvement. OCA transplantation affords the transfer of a size-matched allograft of mature hyaline cartilage with its associated subchondral bony scaffold. Indications include primary or secondary management of large, high-grade chondral or osteochondral defects secondary to trauma, developmental malformation, osteonecrosis, or other focal degenerative disease. Contraindications include end-stage osteoarthritis, uncorrected malalignment, ligament or meniscus deficiency, and inflammatory joint disease. Improvements in surgical technique, allograft storage, and tissue availability have created more reproducible clinical results and increased chondrocyte viability. Long-term (>10 year) graft survival rates have been shown to be between 70% and 91%, and the procedure has been shown to be cost-effective based on cost per quality-adjusted life year. Finally, OCA transplantation has been shown to provide excellent return to play rate for athletes with medium-to-large cartilage lesions. OCA transplantation is therefore an important option in the treatment algorithm of articular cartilage injuries.

High-Speed Centrifugation Efficiently Removes Immunogenic Elements in Osteochondral Allografts.

The current clinical pulse lavage technique for flushing fresh osteochondral allografts (OCAs) to remove immunogenic elements from the subchondral bone is ineffective. This study aimed to identify the optimal method for removing immunogenic elements from OCAs. We examined five methods for the physical removal of immunogenic elements from OCAs from the femoral condyle of porcine knees. We distributed the OCAs randomly into the following seven groups: (1) control, (2) saline, (3) ultrasound, (4) vortex vibration (VV), (5) low-pulse lavage (LPL), (6) high-pulse lavage (HPL), and (7) high-speed centrifugation (HSC). OCAs were evaluated using weight measurement, micro-computed tomography (micro-CT), macroscopic and histological evaluation, DNA quantification, and chondrocyte activity testing. Additionally, the subchondral bone was zoned to assess the bone marrow and nucleated cell contents. One-way ANOVA and paired two-tailed Student's t-test are used for statistical analysis. Histological evaluation and DNA quantification showed no significant reduction in marrow elements compared to the control group after the OCAs were treated with saline, ultrasound, or VV treatments; however, there was a significant reduction in marrow elements after LPL, HPL, and HSC treatments. Furthermore, HSC more effectively reduced the marrow elements of OCAs in the middle and deep zones compared with LPL (p < 0.0001) and HPL (p < 0.0001). Macroscopic evaluation revealed a significant reduction in blood, lipid, and marrow elements in the subchondral bone after HSC. Micro-CT, histological analyses, and chondrocyte viability results showed that HSC did not damage the subchondral bone and cartilage; however, LPL and HPL may damage the subchondral bone. HSC may play an important role in decreasing immunogenicity and therefore potentially increasing the success of OCA transplantation.

Treatment of osteochondral injuries of the humeral head using fresh osteochondral allograft transplantation

BackgroundLarge osteochondral lesions of the humeral head can result from locked posterior dislocations, avascular necrosis, and osteochondritis dissecans. Fresh osteochondral allograft (OCA) transplantation is a treatment option for young patients with focal osteochondral defects of the humeral head. The purpose of this case series was to assess graft survivorship, subjective patient-reported outcomes (PROMs), and satisfaction among seven patients who underwent OCA transplantation of the humeral head. MethodsWe identified seven patients who underwent humeral head OCA transplantation between 2008 and 2017. A custom questionnaire for patient reported outcome measures including ASES, QuickDASH, Likert satisfaction, and reoperations was mailed to each patient. Clinical failure was defined as further surgery that involved removal of the allograft. ResultsMedian follow-up duration was 10 years (range, 4.6 to 13.5 years) with a median age of 21.6 years (range, 18.5 to 43.5 years). Most patients (86%) reported improved function and reduced pain. At final follow-up, 71% of patients reported ongoing problems with their shoulder including pain, stiffness, clicking/grinding, limited range of motion, and instability. Return to recreational activities was high at 86% but 43% expressed limitations with activity due to their shoulder. Overall satisfaction was high at 71% with mean ASES and QuickDASH scores at 62.4 and 29.2 respectively. Reoperation after OCA occurred in one patient (14%). ConclusionsAmong this case series of seven patients who underwent OCA transplantation of the humeral head, patient satisfaction was high at 10 year follow-up and most returned to recreational activity although most also had persistent shoulder symptoms.

Combined Trochlear, Patellar, Medial and Lateral Condyle Fresh Osteochondral Allograft Transplantation: A Case Report

Background: This is a case report of a 41-year-old man with torsional knee trauma in 2019 and chondral lesions. Previous microfracture had failed, and the patient presented with a dull pain and knee effusion. Imaging revealed multiple focal lesions including trochlea, patella, medial condyle, and lateral condyle. Fresh osteochondral allograft (OCA) transplantation is a versatile treatment for large defects as it is based on mature, living hyaline cartilage attached to a bone interface. A patient with multiple chondral lesions is rare, and this report presents a case with multiple symptomatic large focal lesions in the knee that underwent a fresh OCA in all 3 knee compartments. Indications: Osteochondral allograft is indicated for patients who present with activity-related pain and recurrent knee effusion. Contraindications are patient clinical conditions that may lead to complications, such as tobacco use, inflammatory arthritis, or septic arthritis. Technique Description: After the chondral defect is exposed, an appropriate allograft Mega-OATS sizer (15-30 mm) is chosen. Cartilage and the subchondral bone are drilled until the desired depth. The donor allograft is drilled in the desired diameter, and excess bone is removed according to the previous measurements of the recipient site. The graft is advanced with firm pressure into the created socket. Postoperative rehabilitation includes a limited range of motion and proprioceptive weightbearing in the first 2 weeks but expected total weightbearing and a full range of motion by the sixth week. Results: Range of motion was full by 6 weeks of surgery. The effusion lasted for 2 months after the surgery. Fresh OCA is a good surgical option for patients with multiple large chondral defects. Discussion/Conclusion: Patient satisfaction is high since the mature cartilage leads to a fast rehabilitation compared with the other surgical procedures for large chondral defects. This technique appears to be effective also for multiple focal lesions as presented in this article. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form.

Utility of Talus Osteochondral Allograft Augmentation for Varying Hill-Sachs Lesion Sizes: A Cadaveric Study.

Humeral head reconstruction with fresh osteochondral allografts (OCA) serves as a potential treatment option for anatomic reconstruction. More specifically, talus OCA is a promising graft source because of its high congruency with a dense cartilaginous surface. To analyze the surface geometry of the talus OCA plug augmentation for the management of shoulder instability with varying sizes of Hill-Sachs lesions (HSLs). Controlled laboratory study. Seven fresh-frozen cadaveric shoulders were tested in this study. The humeral heads were analyzed using actual patients' computed tomography scans. Surface laser scan analysis was performed on 7 testing states: (1) native state; (2) small HSL; (3) talus OCA augmentation for small HSL; (4) medium HSL; (5) talus OCA augmentation for medium HSL; (6) large HSL; and (7) talus OCA augmentation for large HSL. OCA plugs were harvested from the talus allograft and placed in the most medial and superior aspect of each HSL lesion. Surface congruency was calculated as the mean absolute error and the root mean squared error in the distance. A 1-way repeated-measures analysis of variance was performed to evaluate the effects of the difference in the HSL size and associated talus OCA plugs on surface congruency and the HSL surface area. The surface area analysis of the humeral head with the large (1469 ± 75 mm2), medium (1391 ± 81 mm2), and small (1230 ± 54 mm2) HSLs exhibited significantly higher surface areas than the native state (1007 ± 88 mm2; P < .001 for all sizes). The native state exhibited significantly lower surface areas as compared with after talus OCA augmentation for large HSLs (1235 ± 63 mm2; P < .001) but not for small or medium HSLs. Talus OCA augmentation yielded improved surface areas and congruency after treatment in small, medium, and large HSLs (P < .001). Talus OCA plug augmentation restored surface area and congruency across all tested HSLs, and the surface area was best improved with the most common HSLs-small and medium. Talus OCA plugs may provide a viable option for restoring congruity of the shoulder in patients with recurrent anterior glenohumeral instability and an HSL.

All-Arthroscopic Treatment of Off-Track Hill–Sachs Lesions Using Fresh Osteochondral Allograft Plugs: “Rocks in a Stream”

Osteochondral allograft transplantation is a well-described technique for the treatment of large, engaging Hill–Sachs lesions. Traditionally, osteochondral allografts are size-matched to the defect, which can be expensive and time-consuming, and the majority of described techniques require an open approach. This Technical Note describes an all-arthroscopic approach to Hill–Sachs osteochondral allograft transplantation using premade osteochondral allograft plugs, eliminating the need for size-matching and graft harvest. This approach works not by anatomically filling the defect, but rather by bridging the defect to prevent it from engaging the glenoid.

Humeral Head Reconstruction With Osteochondral Allograft: Bone Plug Optimization for Hill-Sachs Lesions Using CT-Based Computer Modeling Analysis.

Engaging Hill-Sachs lesions (HSLs) pose a significant risk for failure of surgical repair of recurrent anterior shoulder instability. Reconstruction with fresh osteochondral allograft (OCA) has been proposed as a treatment for large HSLs. To determine the optimal characteristics of talus OCA bone plugs in a computer-simulated HSL model. Descriptive laboratory study; Level of evidence, 6. Included were 132 patients with recurrent anterior instability with visible HSLs; patients who had multidirectional instability or previous shoulder surgery were excluded. Three-dimensional computed tomography models were constructed, and a custom computer optimization algorithm was generated to maximize bone plug surface area at the most superior apex (superiorization) and minimize its position relative to the most medial margin of the HSL defect (medialization). The optimal number, diameter, medialization, and superiorization of the bone plug(s) were reported. Percentages of restored glenoid track width and conversion from off- to on-track HSLs after bone plug optimization were calculated. A total of 86 patients were included in the final analysis. Off-track lesions made up 19.7% of HSLs and, of these, the mean bone plug size was 9.9 ± 1.4 mm, with 2.2 mm ± 1.7 mm of medialization and 3.3 mm ± 2.9 mm of superiorization. The optimization identified 21% of HSLs requiring 1 bone plug, 65% requiring 2 plugs, and 14% requiring 3 plugs, with a mean overall coverage of 60%. The mean width of the restored HSLs was 68%, and all off-track HSLs (n = 17) were restored to on-track. A Jenks natural-breaks analysis calculated 3 ideal bone plug diameters of 8 mm (small), 10.4 mm (medium), and 12 mm (large) in order to convert this group of HSLs to on-track. Using a custom computer algorithm, we have demonstrated the optimal talus OCA bone plug diameters for reconstructing HSLs to successfully restore the HSL track and, on average, 60% of the HSL surface area and 68% of the HSL width. Reconstructing HSLs with talus OCA is a promising treatment option with excellent fit and restoration of HSLs. This study will help guide surgeons to optimize OCA bone plugs from the humeral head, femoral head, and talus for varying sizes of HSLs.

Paper 69: Do Patients Participate in Sports or Recreational Activity After Osteochondral Allograft Transplantation of the Talus?

Objectives: Fresh osteochondral allograft (OCA) transplantation has been reported as a viable treatment option for chondral lesions of the talus, but there is insufficient data regarding patients’ participation in sports or recreational activity following the procedure. The purpose of this study was to assess the frequency of patients who participated in sports or recreational activity following OCA of the talus. Methods: We identified 36 ankles in 34 patients (70% well trained or highly competitive athletes) who underwent OCA transplantation of the talus. Mean age was 36 years and 50% were male. Postoperatively, participation in sport or recreational activity, foot and ankle ability measure (FAAM) scores, American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot scores, and patient satisfaction with the results of surgery were assessed. Further surgery on the ankle was captured, and OCA failure was defined as any operation that involved removal of the allograft. Results: At a mean follow up of 8.6 years, 67% of patients reported that they had participated in sports or recreational activity after the OCA transplantation. Among those who participated in sport or recreation, 68% returned to their pre-injury sport, 21% played in competitive sports, and 95% participated in regular exercise. Following the OCA transplantation, 17% of ankles required further surgery and 11% were classified as OCA failures (underwent revision OCA transplantation or fusion). There was significant improvement in FAAM and AOFAS ankle-hindfoot scores, and 79% of patients were either satisfied or extremely satisfied with the results of surgery. Survivorship of the OCA transplantation was 94% at five years and 85% at ten years. Conclusions: Fresh OCA transplantation is a reasonable surgical option for osteochondral defects of the talus for young, active patients who have failed non-operative management. Most patients participate in sports or recreational activity following OCA transplantation of the talus.

Application of 3D Modeling Software to Preoperative MRI for Prediction of Surface Area of Tissue Applied During Osteochondral Allograft Reconstruction of the Knee.

Preoperative magnetic resonance imaging (MRI) is used to estimate the quantity of tissue provided for fresh osteochondral allograft (FOCA) in the knee. Use of 3-dimensional (3D) MRI modeling software for this purpose may improve defect assessment, providing a more accurate estimate of osteochondral allograft tissue required and eliminating the possibility of acquiring an inadequate quantity of tissue for transplant surgery. To evaluate the capacity of damage assessment (DA) 3D MRI modeling software to preoperatively estimate the osteochondral allograft surface area used in surgery. Cohort study (diagnosis); Level of evidence, 2. Included were 36 patients who had undergone FOCA surgery to the distal femur. Based on the preoperative MRI scans, the DA software estimated the total surface area of the lesion as well as the surface areas of each subarea of injury: full-thickness cartilage injury (International Cartilage Repair Society [ICRS] grade 4), partial-thickness cartilage injury (ICRS grade 2-3), bone marrow edema, bone loss, and bone cyst. The probability of overestimation of graft tissue areas by the DA software was calculated using a Bayes-moderated proportion, and the relationship between the prediction discrepancy (ie, over- or underestimation) and the magnitude of the DA estimate was assessed using nonparametric local-linear regression. The DA total surface area measurement overestimated the actual area of FOCA tissue transplanted 81.6% (95% CI, 67.2%-91.4%) of the time, corresponding to a median overestimation of 3.14 cm2, or 1.78 times the area of FOCA transplanted. The DA software overestimated the area of FOCA transplanted 100% of the time for defect areas measuring >4.52 cm2. For defects <4.21 cm2, the maximum-magnitude underestimation of tissue area was 1.45 cm2 (on a fold scale, 0.63 times the transplanted area); a plausible heuristic is that multiplying small DA-measured areas of injury by a factor of ∼1.5 would yield an overestimation of the tissue area transplanted most of the time. The DA 3D modeling software overestimated osteochondral defect size >80% of the time in 36 distal femoral FOCA cases. A policy of consistent but limited overestimation of osteochondral defect size may provide a more reliable basis for predicting the minimum safe amount of allograft tissue to acquire for transplantation.

The “BioHumi" Humeral Head Osteochondral Allograft Transplantation for Reverse Hill-Sachs Lesion of the Shoulder

Osteochondral defects of the shoulder due to posterior instability are less frequent than those caused by anterior instability. Although uncommon, locked posterior dislocations can create sizable osteochondral lesions of the anterior humeral head known as reverse Hill-Sachs lesions. Treatment of these defects to restore the congruent contour of the glenohumeral joint is essential to reduce recurrence of instability and prevent long-term sequelae of arthritis. Historically, nonanatomic options, such as transposition of the subscapularis tendon or lesser tuberosity into the defect and humeral rotational osteotomy, have been endorsed to treat reverse Hill-Sachs lesions. More contemporary techniques have focused on restoring not only the bony architecture but also the chondral surface using fresh osteochondral allografts. The evolution of this approach has been challenging because of the large impacted wedge-shaped defect typically encountered with a locked posterior dislocation. Many surgeons employ techniques using multiple circular grafts or customizing a nonanatomic graft to fill these defects. Given the unstable nature of these grafts, metallic screws are often placed through the chondral surface for fixation. The evolution of the “BioHumi” technique has made treatment of large reverse Hill-Sachs lesions technically simpler and more reproducible using innovative instrumentation to transplant an elliptical osteochondral allograft.

Early Postoperative CT Scan Provides Prognostic Data on Clinical Outcomes of Fresh Osteochondral Transplantation of the Knee

Background: There is a lack of information regarding the ability of imaging studies to predict clinical outcomes after fresh osteochondral allograft (FOCA) transplantation of the knee. Purpose: To determine the value of computed tomography (CT) scans to predict the clinical outcome of FOCA transplantation using the assessment computed tomography osteochondral allograft (ACTOCA) score. Study Design: Cohort study; Level of evidence, 3. Methods: We prospectively collected data from all consecutive patients who underwent FOCA transplantation for osteochondral knee lesions at one institution between August 2017 and August 2019. All patients were followed up for a minimum of 2 years. CT scans performed 6 months after surgery were evaluated by a musculoskeletal radiologist using the ACTOCA scoring system. The radiologist was blinded to the patient’s medical history. Clinical outcomes were assessed preoperatively and at 12 and 30 months postoperatively using the International Knee Documentation Committee (IKDC) score, the Kujala score, the Tegner activity scale, and the Western Ontario Meniscal Evaluation Tool (WOMET) score. Results: A total of 38 cases were included. The ACTOCA score at 6 months after surgery showed a statistically significant correlation with clinical results at 12 and 30 months. The correlation was better at 30 months, showing a high negative correlation with the IKDC score (−0.663) and a moderate negative correlation with the Kujala, WOMET, and Tegner scores (−0.593; −0.547, and −0.593, respectively) (P < .001). Conclusion: A statistically significant correlation between the mean ACTOCA score on CT scans at 6 months and the clinical results measured by the IKDC, Kujala, WOMET, and Tegner scores at 30 months confirmed the predictive value of the ACTOCA score for use in clinical practice.

Osteochondral Allograft Transplant for Combined Medial and Lateral Patellar Cartilage Lesions: The Osteochondral Wide Lesion (OWL) Technique

Symptomatic articular cartilage injuries are often seen in young active patients and athletes. Magnetic resonance imaging screening examinations have frequently identified such lesions in athletic patients. Patellofemoral chondral defects were previously identified as the most common knee cartilage lesion in high-level athletes. Chondral defects measuring 2 cm2 or greater and complex cartilage defects involving bone loss are ideally replaced with fresh osteochondral allograft. We describe a technique indicated for patients with symptomatic and recurrent anterior knee pain associated with osteochondral patellar defects including the lateral and medial patellar facets. Patients who have undergone previous interventions, including membrane techniques, microfracture, or autologous chondral transplantation, without clinical benefit are also eligible to undergo osteochondral allograft transplantation for combined medial and lateral patellar cartilage lesions, that is, the osteochondral wide lesion (OWL) technique.

A Comparative Study Using Fluorescent Confocal Microscopy and Flow Cytometry to Evaluate Chondrocyte Viability in Human Osteochondral Allografts.

The preservation conditions of fresh osteochondral allografts for clinical applications are critical due their objective: to transplant mature hyaline cartilage containing viable chondrocytes, maintaining their metabolic activity and also preserving the structural and functional characteristics of the extracellular matrix. The aim of the present study was to compare fluorescence confocal microscopy and flow cytometry techniques to evaluate the viability of the chondrocytes present in the osteochondral tissue, in order to determine their effectiveness and thus ensure reproducibility and robustness of the analysis. To this end, osteochondral allografts from human cadaveric donors were preserved at 4 °C for 3 weeks in a preservation medium supplemented with antibiotic and antifungal agents. Cell viability of chondrocytes was determined by monitoring the cartilage for 3 weeks of preservation by confocal fluorescence microscopy and flow cytometry, obtaining cell viabilities of 83.7 ± 2.6% and 55.8 ± 7.8% for week three, respectively. The confocal fluorescence microscopy approach is more advantageous and accurate, as it correlates better with actual cell viability values for monitoring osteochondral graft preservation, detecting only the cells that died a natural death associated with the preservation method.

Talar Allograft Preparation for Treatment of Reverse Hill-Sachs Defect in Recurrent Posterior Shoulder Instability

Reverse Hill-Sachs lesions (rHSLs) after chronic posterior shoulder instability are important to recognize and treat appropriately. Treatment options for posterior instability with rHSL in the current literature are primarily based on percentage of humeral bone loss. In cases of moderate (25% to 50%) anterolateral humeral head bone loss, fresh osteochondral allografts are preferred. Recent literature has indicated that the talus serves as a robust grafting alternative site for the humeral head, as the talar dome shows high congruency and offers variable sizes. The purpose of this Technical Note is, therefore, to describe our technique for talus allograft preparation for the treatment of a large rHSL that highlights precise cutting anatomy, sizing options, and use of orthobiologics to ensure excellent talus union to the native humeral head surface.

Paper 42: Effects of Blood Type Mismatching on Functional Graft Survival after Osteochondral Allograft Transplantation

Objectives:To explore a factor that may contribute to potentially detrimental sub-rejection immune responses, we compared donor and recipient blood types following osteochondral allograft (OCA) transplants from a subset of patients in an IRB-approved dedicated lifelong registry to determine potential relationships for blood type mismatches with documented graft failures. The study was designed to test the hypothesis that OCA transplantation patients receiving blood type mismatched allografts would be more likely to require OCA revision or artificial arthroplasty surgery compared to those receiving donor-recipient matched allografts.Methods:A subset of patients was selected from those enrolled (n=414) in our center’s IRB-approved lifelong registry for OCA transplantation clinical outcomes. This subset included patients with complete donor and recipient ABO and Rh Factor data available such that there was a 2:1 ratio of successful versus failed outcomes for age-, BMI-, and joint-matched OCA transplant recipients for statistical analyses. Donor blood type information was obtained from the respective tissue banks. Recipient blood type information was obtained from electronic medical records. Patients who required OCA revision or artificial arthroplasty were defined as graft failures. Outcomes were assessed for all patients included in the blood type mismatching analyses. Osteochondral tissues that were resected from the knee, hip, and ankle of patients undergoing standard-of-care revision or arthroplasty surgeries, and that otherwise would be discarded, were recovered for histologic assessments. Subjective histologic assessments were performed by a pathologist who was blinded to patient demographics, blood typing information, outcomes data, and tissue source. When aggregates of lymphocytes and plasma cells were observed surrounding small blood vessels (consistent with an immune response), immunohistochemistry for CD3, CD8, and CD20 was performed to further characterize the lymphocytes (T cell marker, cytotoxic T lymphocytes, and B cell marker, respectively) for subjective assessment of relevant immune responses. Subjects were grouped by ABO blood type, Rh Factor, and both. Histologically evaluated failures were separated by immune response as positive or negative. Fisher’s exact tests were used for statistical analyses with a p-value of less than 0.05 set a priori to define statistical significance.Results:A total of 103 patients were included for analysis with 33 of these requiring OCA revision or artificial arthroplasty. Of the clinical failures, 18 had previously transplanted osteochondral allograft tissues recovered for histological assessment. Twelve (66%) of these recovered OCAs had aggregates of CD3+, CD8+, and CD20+ lymphocytes around small blood vessels in the bone marrow spaces and adipose/collagenous tissue of the previously transplanted allograft. The remaining resected OCAs (34%) did not show a similar pattern of T- and B-cell infiltrates around blood vessels. Other histologic abnormalities associated with failed OCAs included avascular necrosis, subchondral micro and macro fractures, subchondral collapse, and/or articular cartilage erosion or delamination. No statistically significant differences in proportions for success versus failure based on mismatches for ABO type, Rh Factor, or both were noted. Similarly, no statistically significant differences in proportions for positive versus negative immune responses based on mismatches for ABO type, Rh Factor, or both were noted.Conclusions:Donor-recipient mismatches for ABO blood type and/or Rh Factor were not associated with higher likelihood for patients to require OCA revision or artificial arthroplasty surgery. Similarly, donor-recipient mismatches for ABO blood type and/or Rh Factor were not associated with higher likelihood for positive immune responses in previously implanted OCA tissues recovered from patients who required revision or artificial arthroplasty surgeries. However, two-thirds of the tissues recovered from graft failure cases had T- and B-cell infiltrates, suggesting sub-rejection immune responses occur after OCA transplantation that should be further investigated to determine potential mechanistic relationships with graft failures. The results of the present study support current clinical practice for transplantation of fresh OCAs, which does not require HLA or blood type matching or immunosuppressive medication for recipients. However, histologic assessments suggest that sub-rejection immune responses may play a role in graft failures and should be further investigated.

Salvage Procedures: Last Chance Before Arthroplasty

Lower-extremity misalignment hastens the development of chondral and osteochondral knee lesions. In active young patients with bipolar osteochondral lesions, the bipolar fresh osteochondral allograft procedure is a useful salvage treatment option. Although the surgical technique is technically demanding and high reoperation and failure rates are expected, patients with surviving allografts show a significant clinical improvement. Careful patient selection is key to delivering desired results. In this review, we present and discuss recent surgical techniques and developments in bipolar fresh osteochondral allograft procedures.

Midterm Prospective Evaluation of Structural Allograft Transplantation for Osteochondral Lesions of the Talar Shoulder.

In cases of large osteochondral lesions of the talus (OLTs), fresh structural or bulk osteochondral allograft transplantation has yielded favorable outcomes in several retrospective and few prospective case series. The purpose of this study was to prospectively evaluate patients who received fresh structural allograft transplantation of the talar shoulder. A prospective evaluation of patients who received a fresh structural allograft of an OLT was performed. Preoperative imaging included magnetic resonance imaging (MRI) and/or computed tomography (CT) with plain radiographs. The following patient-reported outcomes questionnaires were administered preoperatively and yearly after surgery: 36-Item Short-Form Health Survey (SF-36), visual analog scale (VAS) for pain, and the Short Musculoskeletal Functional Assessment (SMFA). Preoperative and postoperative imaging were evaluated for allograft assimilation, evidence of arthritic changes, or functional range of motion abnormalities. Thirty-one patients with a mean age of 41.4 years (±14.1, range 18-69) underwent structural fresh osteochondral allograft transplantation to the talar shoulder and were included in this study. The mean follow-up was 56.2 months (±36.1, range 24-142). The majority of patients were female (n=17, 54.8%), reported some history of prior ankle trauma (n=21, 67.7%), and underwent prior ankle surgery (n=23, 74.2%). The mean lesion size on CT scan was 1879 mm3 (n = 27) compared to the mean lesion size of 3877 mm3 (n = 21) on MRI. There was a significant improvement in the mean preoperative VAS score (P < .0001), SF-36 score (P < .0005), SMFA bother index (P < .0015), and the SMFA function index (P < .0001) at final follow-up. A total of 15 (48.4%) patients underwent an additional surgery following their osteochondral allograft transplant, most commonly arthroscopic debridement or removal of hardware, performed at an average of 25.2 (±13.0) from their index procedure. There was one failure that required a total ankle replacement. The overall graft survival rate was 96.8%. Fresh, structural allograft transplantation resulted in significant improvement in patient-reported postoperative pain and function in patients suffering from OLTs. The graft survival rate was 96.8% at a mean of 56.2 months follow-up, with half of patients requiring a second procedure. Level IV, prospective case series.

Osteochondral Allograft Transplantation for a Cartilage Defect of the Humeral Capitellum

Background: Cartilage defects of the humeral capitellum most frequently present as osteochondritis dissecans (OCD) in young overhead athletes, such as baseball players. Historically, surgical options have included debridement, marrow stimulation, and osteochondral autograft transplantation. Fresh osteochondral allograft (OCA) transplantation comprises an additional treatment option that can structurally restore osteochondral defects and has demonstrated satisfactory outcomes without the donor-site morbidity associated with osteochondral autograft transplantation. Indication: OCA transplantation provides structural restoration of the articular surface and can be used for large (&gt;1 cm diameter) lesions not amenable to refixation. Additionally, OCA transplantation can address both chondral and subchondral pathology and is suited for the treatment of failed previous surgical interventions, such as debridement or marrow stimulation. Technique Description: Following diagnostic arthroscopy, an anconeus splitting mini-open approach was performed to expose the capitellar defect. The defect was measured to be 10 mm, and a central guide pin was placed. A 10-mm reamer was used to prepare the defect bed to a depth of 8 mm. An OCA plug was then cut from a fresh femoral hemicondyle to match the prepared defect. The graft was soaked in bone marrow aspirate concentrate harvested from the iliac crest, and the plug was then inserted into the defect and tamped to be concentric with the surrounding articular cartilage. Results: OCA transplantation of the capitellum allows for the restoration of the articular surface with a structural graft and can be used for large defects and revision cases. While OCA transplantation is well described in the knee with long-term efficacy, the application of this technique to the capitellum is relatively recent. Recent case series for the capitellum have displayed significant improvements in patient-reported outcome measures and predictable return to sports. Discussion/Conclusion: OCA transplantation for the humeral capitellum provides an effective treatment option for large, unstable cartilage lesions not amenable to refixation. The procedure allows for restoration of the articular surface and can provide improvements in pain and function as well as return to sport.