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BACKGROUND: Osteochondral allograft (OCA) transplantation is an important surgical technique for full-thickness chondral defects in the knee. For patients undergoing this procedure, topography matching between the donor and recipient sites is essential to limit premature wear of the OCA. Currently, there is no standardized process of donor and recipient graft matching. PURPOSE: To evaluate a novel topography matching technique for distal femoral condyle OCA transplantation using 3-dimensional (3D) laser scanning to create 3D-printed patient-specific instrumentation in a human cadaveric model. STUDY DESIGN: Descriptive laboratory study. METHODS: Human cadaveric distal femoral condyles (n = 12) underwent 3D laser scanning. An 18-mm circular osteochondral recipient defect was virtually created on the medial femoral condyle (MFC), and the position and orientation of the best topography-matched osteochondral graft from a paired donor lateral femoral condyle (LFC) were determined using an in silico analysis algorithm minimizing articular step-off distances between the edges of the graft and recipient defect. Distances between the entire surface of the OCA graft and the underneath surface of the MFC were evaluated as surface mismatch. Donor (LFC) and recipient (MFC) 3D-printed patient-specific guides were created based on 3D reconstructions of the scanned condyles. Through use of the guides, OCAs were harvested from the LFC and transplanted to the reamed recipient defect site (MFC). The post-OCA recipient condyles were laser scanned. The 360° articular step-off and cartilage topography mismatch were measured. RESULTS: The mean cartilage step-off and graft surface mismatch for the in silico OCA transplant were 0.073 ± 0.029 mm (range, 0.005-0.113 mm) and 0.166 ± 0.039 mm (range, 0.120-0.243 mm), respectively. Comparatively, the cadaveric specimens postimplant had significantly larger step-off differences (0.173 ± 0.085 mm; range, 0.082-0.399 mm; P = .001) but equivalent graft surface topography matching (0.181 ± 0.080 mm; range, 0.087-0.396 mm; P = .678). All 12 OCA transplants had mean circumferential step-off differences less than a clinically significant cutoff of 0.5 mm. CONCLUSION: These findings suggest that the use of 3D-printed patient-specific guides for OCA transplantation has the ability to reliably optimize cartilage topography matching for LFC to MFC transplantation. This study demonstrated substantially lower step-off values compared with previous orthopaedic literature when also evaluating LFC to MFC transplantation. Using this novel technique in a model performing MFC to MFC transplantation has the potential to yield further enhanced results due to improved radii of curvature matching. CLINICAL RELEVANCE: Topography-matched graft implantation for focal chondral defects of the knee in patients improves surface matching and has the potential to improve long-term outcomes. Efficient selection of the allograft also allows improved availability of the limited allograft sources.

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BACKGROUND: Chondrocyte viability is associated with the clinical success of osteochondral allograft (OCA) transplantation. PURPOSE: To investigate the effect of distal femoral OCA plug harvest and recipient site preparation on regional cell viability using traditional handheld saline irrigation versus saline submersion. STUDY DESIGN: Controlled laboratory study. METHODS: For each of 13 femoral hemicondyles, 4 cartilage samples were harvested: (1) 5-mm control cartilage, (2) 15-mm OCA donor plug harvested with a powered coring reamer and concurrent handheld saline irrigation ("traditional"), (3) 15-mm OCA donor plug harvested while submerged under normal saline ("submerged"), and (4) 5-mm cartilage from the peripheral rim of a recipient socket created with a 15-mm cannulated counterbore reamer to a total depth of 7 mm with concurrent handheld saline irrigation ("recipient"). The 15 mm-diameter plugs were divided into the central 5 mm and the peripheral 5 mm (2 edges) for comparisons. Samples were stained using calcein and ethidium, and live/dead cell percentages were calculated and compared across groups. RESULTS: Compared with the submerged group, the traditional group had significantly lower percentages of live cells across the whole plug (71.54% ± 4.82% vs 61.42% ± 4.98%, respectively; P = .003), at the center of the plug (72.76% ± 5.87% vs 62.30% ± 6.11%, respectively; P = .005), and at the periphery of the plug (70.93% ± 4.51% vs 60.91% ± 4.75%, respectively; P = .003). The traditional group had significantly fewer live cells in all plug regions compared with the control group (77.51% ± 9.23%; P < .0001). There were no significant differences in cell viability between the control and submerged groups (whole: P = .590; center: P = .713; periphery: P = .799). There were no differences between the central and peripheral 5-mm plug regions for the traditional (62.30% ± 6.11% vs 60.91% ± 4.75%, respectively; P = .108) and submerged (72.76% ± 5.87% vs 70.93% ± 4.51%, respectively; P = .061) groups. The recipient group (61.10% ± 5.02%) had significantly lower cell viability compared with the control group (P < .0001) and the periphery of the submerged group (P = .009) but was equivalent to the periphery of the traditional group (P = .990). CONCLUSION: There was a significant amount of chondrocyte death induced by OCA donor plug harvesting using a powered coring reamer with traditional handheld saline irrigation, which was mitigated by harvesting the plug while the allograft was submerged under saline. CLINICAL RELEVANCE: Mitigating this thermally induced damage by harvesting the OCA plug while the allograft was submerged in saline maintained chondrocyte viability throughout the plug and may help to improve the integration and survival of OCAs.

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OBJECTIVE: To investigate the cytokine release profile and histological response of human cartilage after exposure to autologous conditioned serum (ACS) and freeze-dried allogenic conditioned serum (FD-CS). DESIGN: Cartilage explants were collected from 6 patients undergoing total knee arthroplasty. ACS and FD-CS were created from patient serum samples. Cartilage samples were divided into 6 groups: (1) untreated control, (2) ACS, (3) FD-CS, (4) untreated interleukin (IL)-1ß (5 ng/ml), (5) IL-1ß + ACS, and (6) IL-1ß + FD-CS. After 12 days, cartilage samples were analyzed with glycosaminoglycan (GAG) concentration normalized to wet weight while comparing cytokine concentrations, and histological scoring. RESULTS: There was a significant decrease in pathology scoring for ACS (P = 0.0368) and FD-CS (P = 0.0368) in the IL-1ß injury groups compared with the untreated IL-1ß insult group. ACS and FD-CS significantly mitigate the IL-1ß induced increase in basic fibroblast growth factor (bFGF) (P = 0.0009 and P = 0.0002, respectively). FD-CS showed a significant decrease in IL-1ß concentration in the presence of IL-1ß insult compared with the untreated IL-1ß group (P < 0.0001). ACS-treated samples had significantly higher concentration of tumor necrosis factor (TNF)-α independent of IL-1ß when compared with samples not treated with biologics (P = 0.0053). CONCLUSIONS: Explanted osteoarthritic cartilage responds favorably and equivalently to treatment with ACS and FD-CS from a histological perspective. Both ACS and FD-CS were able to mitigate the IL-1ß-induced increases in bFGF and FD-CS lowered IL-1ß concentration while increasing interleukin-1 receptor antagonist (IL-1Ra) concentration. Although the cytokine profile of cartilage tissue explants treated with FD-CS appears to be different than that of ACS, this difference does not seem to affect biologic activity of FD-CS.

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A lateral opening-wedge distal femoral osteotomy is useful to offload the lateral tibiofemoral compartment for focal chondral defects or isolated lateral compartment arthritis. Although beneficial for these lateral compartment disorders, a distal femoral osteotomy requires careful forethought to optimize correction accuracy and safety. We recommend the following for effective execution of a distal femoral osteotomy: (1) Plan the desired correction preoperatively while accounting for an individual patient's anatomy and femoral width. (2) Perform an iliotibial band Z-lengthening for large deformity corrections to not overconstrain the lateral structures. (3) Use the plate to help guide the level of the osteotomy, which will facilitate bony contact after the osteotomy and decrease plate prominence. (4) Perform the osteotomy with a saw anteriorly and an osteotome posteriorly for safety and stop the osteotomy approximately 1 cm short of the far cortex. (5) Fashion tricortical wedge grafts at the height of the planned correction to maintain reduction and facilitate plate placement. (6) Control the plate position to lie optimally at the level of the osteotomy, ensuring it is not proud and is parallel with the femoral shaft. With these presurgical and intraoperative steps, a lateral opening-wedge distal femoral osteotomy can be performed effectively.

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BACKGROUND: All-suture anchors and knotless anchors are increasingly used in the repair of anteroinferior labral tears in patients with shoulder instability. Optimal repair constructs may limit recurrent instability. PURPOSE: To perform a quantitative biomechanical comparison of 3 labral fixation devices for soft tissue Bankart lesions: knotless soft-body tensionable anchor (SB knotless), knotted soft-body anchor (SB knotted), and knotless hard-body PEEK (polyether ether ketone) interference anchor (HB knotless). STUDY DESIGN: Controlled laboratory study. METHODS: A total of 21 glenoid specimens were randomized into 3 groups: SB knotless, SB knotted, and HB knotless. Artificial Bankart lesions were created at the anteroinferior labrum. Anchors were placed at the 3:30, 4:30, and 5:30 clockface positions, and sutures were passed through 1 cm of tissue. Anchors were tested simultaneously as one construct by pulling capsular tissue connected to the anteroinferior quadrant. Cyclic loading (5-25 N, 100 cycles) was followed by load-to-failure testing (15 mm/min). Biomechanical testing variables were collected, and failure mechanisms were recorded per individual anchor. RESULTS: There were no differences in baseline specimen characteristics. There was no difference in elongation during cyclic loading (P = .40). The ultimate load to failure between SB knotless (309.7 ± 125.6 N), SB knotted (226.4 ± 34.8 N), and HB knotless (256.5 ± 90.5 N) did not significantly differ (P = .25). Failure mechanisms differed among groups (P = .008); mechanisms included anchor pullout (SB knotless: 33.3%; SB knotted: 23.8%; HB knotless: 28.6%), suture pull-through (SB knotless: 66.7%; SB knotted: 38.1%; HB knotless: 33.3%), and anchor fixation method failure, defined as knot failure for knotted anchors or locking mechanism failure for knotless anchors (SB knotless: 0.0%; SB knotted: 38.1%; HB knotless: 38.1%).). CONCLUSION: The SB knotless, SB knotted, and HB knotless labral fixation anchors studied exhibited comparable elongation during cyclic loading, stiffness, and ultimate loads to failure in a cadaveric model. However, the failure mechanisms significantly differed, as SB knotless anchors failed primarily from suture pull-through, while SB knotted and HB knotless anchors were subject to knot failure and locking mechanism failure, respectively. CLINICAL RELEVANCE: These data support the benefit of SB knotless anchors for anteroinferior labral repair in limiting knot failure typically seen with knotted anchors, perhaps demonstrating that all-suture anchors may have better locking mechanism quality than their PEEK counterparts.

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We present an evidence-based approach to optimize the biologic incorporation of osteochondral allografts: (1) The donor graft is gradually rewarmed to room temperature to reverse the metabolic suppression from cold storage. (2) The graft is harvested while submerged in saline to limit thermal necrosis. (3) Subchondral bone depth is preferred at 4 to 6 mm depth (total plug depth ∼5-8 mm including articular cartilage) to reduce graft immunogenicity and to promote incorporation. (4) The bone is prepared with grooves/beveling to decrease impaction forces, increase access to subchondral deep zones during preparation, and promote graft-host interface healing. (5) High-pressure pulsed lavage is used to reduce antigenicity by removing marrow elements. (6) Pressurized carbon dioxide following pulsed lavage further reduces marrow elements and improves graft porosity for orthobiologic incorporation. (7) Orthobiologic substances (e.g., concentrated bone marrow aspirate) may enhance incorporation on imaging and result in greater osteogenic potential. (8) A suture is placed behind the graft to facilitate removal and repositioning; atraumatic graft insertion without high impaction forces maintains chondrocyte viability. These evidence-based pearls for osteochondral allograft handling optimize metabolic activity, reduce thermal necrosis, reduce antigenicity with removal of marrow elements, enhance biologic potential, and maintain chondrocyte viability to optimize biologic healing and clinical success.

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Purpose: To describe the morphology of the adductor tubercle (AT), medial epicondyle (ME), and gastrocnemius tubercle (GT); to quantify their relationships to the medial patellofemoral ligament (MPFL) footprint location; and to classify the reliability of each landmark based on measurement variability. Methods: Eight cadaveric specimens were dissected to expose the following landmarks on the femur: MPFL footprint, AT, ME, and GT. Using the MicroScribe 3D digitizer, each landmark was projected into a 3-dimensional coordinate system and reconstructed into a complex, closed polygon. For each specimen tubercle, the base surface area, volume, height, base:height ratio, sulcus point, and distance from the MPFL footprint center were calculated. Levene's test was performed to evaluate differences in variance of the morphologic parameters between the three osseous structures. Results: The ME had significantly greater variance in volume than the GT (P = .032), and the AT (17.5 ± 3.9) and GT (19.5 ± 3.6) were significantly less variable in base:height ratio than the ME (95.3 ± 19.2; P < .001). The GT was the closest to the MPFL footprint center (7.1 ± 3.1 mm) compared with the AT (13.4 ± 3.6 mm, P = .002) and ME (13.2 ± 2.7 mm, P = .003). However, the tubercles were equally variable in terms of distance to the MPFL footprint center (P = .86). Lastly, the sulcus point was estimated to be on average 1.9 ± 2.9 mm distal and 2.0 ± 2.0 mm posterior to the MPFL center point. Conclusions: The 3 major osseous landmarks of the medial femur have significantly different variances in volume and base:height ratio. Specifically, the variability and elongated morphology of the ME differentiated this landmark from the AT and GT, which demonstrated the most consistent morphology. Clinical Relevance: The results of this study may be useful to accurately locate landmarks for femoral tunnel placement and determine the isometric MPFL point during reconstruction.