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Background: Microfracture is one surgical treatment strategy for osteochondral lesions of the talus (OLTs) but results in fibrocartilage repair tissue, which has inferior mechanical properties to native hyaline cartilage. Biological regulation of microfracture has been suggested to improve the quality of cartilage repair in patients., Purpose: To determine if administration of losartan, fisetin, or losartan and fisetin combined can enhance microfracture-mediated cartilage repair of OLTs in a rabbit model., Study Design: Controlled laboratory study., Methods: Four-month-old female rabbits were divided into the following groups (8 rabbits per group): microfracture only (microfracture), microfracture plus losartan (losartan), microfracture plus fisetin (fisetin), and microfracture plus losartan and fisetin (losartan+fisetin). A 2.7-mm osteochondral defect and 4 microfracture holes were created in the talar dome cartilage. The rabbits were administered losartan (10 mg/kg/day), fisetin (20 mg/kg/day), or losartan and fisetin orally until euthanized 12 weeks after surgery. Gross evaluation, micro-computed tomography, histology, and immunohistochemistry evaluations of the osteochondral defects were performed as well as quantitative polymerase chain reaction of capsule tissue and enzyme-linked immunosorbent assay of serum., Results: The losartan and fisetin groups had increased International Cartilage Regeneration & Joint Preservation Society macroscopic scores with improved cartilage repair and enhanced subchondral bone healing compared with the microfracture group. However, the losartan+fisetin group did not show a synergistic effect. O'Driscoll histology scores were higher in the losartan and fisetin groups compared with the microfracture group, while the losartan+fisetin group had a lower score than the losartan, fisetin, and microfracture groups. Collagen type 2 staining revealed organized chondrocytes in the losartan and fisetin groups, but the losartan+fisetin group did not show improvement when compared with other groups. Fisetin treatment decreased catalase and transforming growth factor-β1-activated kinase 1 expression in capsular tissue., Conclusion: Concomitant microfracture and biological regulation, using oral administration of either losartan or fisetin, may improve cartilage healing of OLTs; however, losartan and fisetin combined in the current drug administration regimen does not appear to provide synergistic effects., Clinical Relevance: Oral intake of losartan or fisetin may result in beneficial effects on microfracture-mediated cartilage repair of OLTs., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This project was funded by a philanthropy gift from the Smead/Byram family. The position of I.K.S. at the Steadman Philippon Research Institute was partially supported by Arthrex. M.J.P has received consulting fees and royalties from Smith & Nephew; royalties and support for education from Linvatec Corporation; research support from Arthrex; speaking fees from Synthes GMBH; and hospitality payments from Siemens Medical Solutions USA. T.O.C. has received consulting fees and royalties from Arthrex and Stryker; holds stock in BICMD; and has received support for education from Gemini Mountain and Wright Medical. J.H. has received royalty payment from Cook Myosite. J.J.R. has received consulting fees from Smith & Nephew and a grant from Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Background: Osteochondral defects of the medial femoral condyle combined with varus malalignment in young and active patients are a debilitating condition, which can result in early osteoarthritis. Osteochondral autologous transfer (OAT) combined with valgus high tibial osteotomy (HTO) might therefore be a comprehensive solution to maintain long-term knee function., Purpose/hypothesis: The purpose of this study was to report clinical results and survivorship after combined OAT and valgus HTO for symptomatic osteochondral defects of the medial femoral condyle in the setting of varus malalignment at a long-term follow-up. It was hypothesized that undergoing combined OAT and valgus HTO would produce favorable clinical results along with a low rate of conversion to arthroplasty., Study Design: Case series; Level of evidence, 4., Methods: All patients treated between 1998 and 2008 with combined valgus HTO and OAT for deep osteochondral defects of the medial femoral condyle and concomitant varus malalignment >2° without meniscal repair/transplantation, osteoarthritis, or ligamentous instability/reconstruction were included. The survival rates of this combined procedure were evaluated. Failure was defined as conversion to knee joint arthroplasty during the follow-up period. Patient-reported outcomes were collected pre- and postoperatively, including the Lysholm score, visual analog scale score, Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity Scale score, and subjective level of satisfaction (scale 0-10)., Results: Of 74 patients who were included for 10-year follow-up, 3 had died. A total of 15 patients were lost to follow-up, so 56 patients could be reevaluated, for a follow-up rate of nearly 80%. The mean age at surgery was 38.8 ± 9.9 years (range, 19.9-62.4 years), and the mean follow-up time was 18.9 ± 3.0 years (median, 18.8 years; range, 14.1-24.8 years). The survival rates were 87% at 10 years, 86% at 15 years, and 77% at 19 years after surgery. At final follow-up, the Lysholm score showed a mean increase of 39 points (95% CI, 25.4-50.0 points; P < .001) from 40 points to 79 points, representing a significant improvement. Overall, 96% of patients surpassed the minimal clinically important difference (MCID) for the Lysholm score. The visual analog scale score decreased by a mean of 4.8 points (range, 5-10 points) from 7.5 points to 2.7 points ( P < .001), and 80% of patients surpassed the MCID. The mean Tegner Activity Scale score was 4.5 ± 1.6, and the mean KOOS subscale scores at final follow-up were as follows: Pain: 81 ± 21 (range, 19-100), Symptoms: 80 ± 22 (range, 21-100), Activities of Daily Living: 85 ± 21 (range, 18-100), Sports: 68 ± 32 (range, 0-100), and Quality of Life: 67 ± 28 (range, 0-100). Overall, 78% of the patients were satisfied with the results of the operation., Conclusion: The combination of OAT and valgus HTO presents a viable treatment option for patients affected by osteochondral defects of the medial femoral condyle and concurrent varus malalignment. A sustained and substantial improvement in clinical outcomes, significantly reduced pain severity, and a high rate of long-term survivorship can be anticipated in the long-term follow-up., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: S.S. is a consultant for Arthrex GmbH, medi GmbH & Co KG, and KLS Martin Group. A.B.I. is a consultant for Arthrex Inc. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Disclosure forms for all authors are available online.

Background: Microfracture is the most common treatment for cartilage defects of the knee. In microfracture surgery, holes are randomly drilled into the subchondral bone. The effect of the hole's location on its interaction with the cartilage defect site and its influence on the healing process is currently uncertain ., Purpose: To investigate the effects of different microfracture locations on healing in a rabbit knee osteochondral defect model., Study Design: Controlled laboratory study., Methods: A total of 29 adult New Zealand White rabbits were divided into 5 groups. In the healthy cartilage control group (n = 5), no surgical procedure was performed. Cylindrical full-thickness cartilage defects (5 × 3 mm) were created in the patellar groove of the remaining 24 rabbits. In the defect control group (n = 6), only the defect was created. A microfracture was performed at the 12-o'clock position (group peripheral single; n = 6), centrally (group central; n = 6), and at the 12- and 6-o'clock positions (group peripheral double; n = 6) of the defect. The animals were sacrificed after 8 weeks. Cartilage healing was evaluated by International Cartilage Regeneration & Joint Preservation Society (ICRS) score, modified O'Driscoll score, immunohistochemical analysis (type 1 collagen, type 2 collagen, and aggrecan), and scanning electron microscopy analysis., Results: In group peripheral double, better cartilage healing was observed in all parameters compared with the other groups ( P < .05). Group peripheral double had the greatest amount of filling, with 79% of the defect area filled with fibrocartilage repair tissue. Group peripheral single demonstrated filling of 73% of the defect area, group central 56%, and the defect control group 45%. The ICRS score was significantly higher in group peripheral single compared with group central and the defect control group. Type 2 collagen and aggrecan immunoreactivity were significantly stronger in group central than group peripheral single and the defect control group ( P < .05)., Conclusion: Microfracture performed at the peripheral margin of the defect had better filling characteristics in a rabbit model. This study suggests that interaction of pluripotent cells released from the microfracture site with the intact cartilage may enhance the quality of the repair tissue., Clinical Relevance: The location of microfracture holes in relation to the peripheral border of the osteochondral defect (to the intact cartilage) is important in both the quality and the quantity of the newly formed repair tissue.

Background: Osteochondral defects of the talus can be effectively treated using microfracture, which is technically safe, accessible, and affordable. However, fibrous tissue and fibrocartilage comprise the majority of tissue repairs resulting from these procedures. These tissue types lack the mechanical characteristics of native hyaline cartilage and might significantly contribute to the decline in long-term outcomes. Recombinant human-bone morphogenetic protein-2 (rhBMP-2) has been shown to promote matrix synthesis and increase cartilage formation, thus enhancing chondrogenesis in vitro., Purpose: This study aimed to evaluate the treatment ability of combining rhBMP-2 with microfracture in rabbit talus osteochondral defect., Study Design: Controlled laboratory study., Methods: A full-thickness chondral defect (3 × 3 × 2 mm) was constructed in the center talar dome of 24 New Zealand White male rabbits, which were then divided into 4 groups of 6. Each group received the appropriate treatment: group 1 (control; no treatment of defect), group 2 (microfracture treatment), group 3 (rhBMP-2/hydroxyapatite treatment), and group 4 (microfracture combined with rhBMP-2/hydroxyapatite treatment). Animals were sacrificed at 2, 4, and 6 weeks postoperatively. The International Cartilage Regeneration & Joint Preservation Society macroscopic score, which considers the degree of defect repair, the integration to the border zone, and the macroscopic appearance, was used to assess the repaired tissue's macroscopic appearance. Subchondral bone regeneration in defects was analyzed using micro-computed tomography, and the histological findings were graded using a modified version of the Wakitani scoring system for osteochondral repair., Results: At 2, 4, and 6 weeks, micro-computed tomography analysis revealed that groups 3 and 4 exhibited subchondral bone healing that was more significantly improved compared with groups 1. No sample showed excessive bone growth from the subchondral bone area. According to macroscopic and histological results, group 4 showed higher-quality cartilage and more accelerated cartilage regeneration than the other groups over time., Conclusion: These findings show that osteochondral defect repair in a rabbit talus model could be effectively accelerated and improved by combining rhBMP-2 with microfracture., Clinical Relevance: Using rhBMP-2 in combination with microfracture may enhance the repair of talar osteochondral lesions.

Background: Magnetic resonance imaging (MRI) is considered to be the gold standard for imaging of osteochondritis dissecans (OCD)., Purpose/hypothesis: The purpose was to determine the additional value of a preoperative computed tomography (CT) scan in adolescent patients with capitellar OCD of the elbow. Consistent with the fact that OCD is a lesion involving the subchondral bone, the hypothesis was that CT would be superior to MRI for imaging OCD of the capitellum., Study Design: Cohort study (diagnosis); Level of evidence, 3., Methods: All patients being treated surgically for an OCD of the capitellum between 2006 and 2016 at one institution were reviewed for preoperative imaging. A total of 28 patients met the inclusion criteria. Corresponding MRI and CT scans were compared retrospectively. Multiple parameters were recorded, with special emphasis on OCD lesion size, fragmentation, and tilt as well as joint surface integrity, loose bodies, and osteophytes., Results: The OCD lesions were best seen on CT scans, whereas MRI T1-weighted images overestimated and T2-weighted images underestimated the size of defects. A subchondral fracture nonunion was found on CT scans in 18 patients, whereas this was seen on MRI T1-weighted images in only 2 patients ( P < .001) and MRI T2-weighted images in 4 patients ( P < .001). Fragmentation of the OCD fragment was found on CT scans in 17 patients but on MRI scans in only 9 patients ( P = .05). Osteophytes as a sign of secondary degenerative changes were seen on CT scans in 24 patients and were seen on MRI scans in 15 patients ( P = .02). Altogether, only 51 of 89 secondary changes including loose bodies, effects on the radial head and ulnohumeral joint, and osteophytes that were seen on CT scans were also seen on MRI scans ( P = .002)., Conclusion: OCD fragmentation and secondary changes were more often diagnosed on CT. These factors indicate OCD instability or advanced OCD stages, which are indications for surgery. In an adolescent who is considered at risk for OCD (baseball, gymnastics, weightlifting, tennis) and who has lateral elbow joint pain with axial or valgus load bearing, CT is our imaging modality of choice for diagnosing and staging OCD of the capitellum.

Background: The first-line clinical strategy for small cartilage/osteochondral defects is microfracture (MF). However, its repair efficacy needs improvement., Hypothesis: Appropriate energy radial shockwave stimulation in MF holes would greatly improve repair efficacy in the porcine osteochondral defect model, and it may obtain comparable performance with common tissue engineering techniques., Study Design: Controlled laboratory study., Methods: Osteochondral defect models (8-mm diameter, 3-mm depth) were established in the weightbearing area of Bama pigs' medial femoral condyles. In total, 25 minipigs were randomly divided into 5 groups: control (Con; without treatment), MF, MF augmentation (MF+; treated with appropriate energy radial shockwave stimulation in MF holes after MF), tissue engineering (TE; treated with compounds of microcarrier and bone marrow mesenchymal stem cells), and sham (as the positive control). After 3 months of intervention, osteochondral specimens were harvested for macroscopic, radiological, biomechanical, and histological evaluations. The statistical data were analyzed using 1-way analysis of variance., Results: Based on the macroscopic appearance, the smoothness and integration of the repaired tissue in the MF+ group were improved when compared with the Con and MF groups. The histological staining suggested more abundant cartilaginous matrix deposition in the MF+ group versus the Con and MF groups. The general scores of the macroscopic and histological appearances were comparable in the MF+ and the TE groups. The high signal areas of the osteochondral unit in the magnetic resonance images were significantly decreased in the MF+ group, with no difference with the TE group. The micro-computed tomography data demonstrated the safety of direct in situ radial shockwave performance. Biomechanical tests revealed that the repaired tissue's Young modulus was highest in the MF+ group and not statistically different from that in the TE group., Conclusion: Direct in situ radial shockwave stimulation with appropriate energy significantly improves the short-term repair efficacy of MF. More encouragingly, the MF+ group in our study obtained repair performance comparable with the TE therapy., Clinical Relevance: This strategy is easy to perform and can readily be generalized with safety and higher cartilage repair efficacy. Moreover, it is expected to be accomplished under arthroscopy, indicating tremendous clinical transformative value.

Background: It is unclear whether the results of osteochondral transplant using autografts or allografts for talar osteochondral defect are equivalent., Purpose: A systematic review of the literature was conducted to compare allografts and autografts in terms of patient-reported outcome measures (PROMs), MRI findings, and complications., Study Design: Systematic review; Level of evidence, 4., Methods: This study was conducted according to the PRISMA guidelines. The literature search was conducted in February 2021. All studies investigating the outcomes of allograft and/or autograft osteochondral transplant as management for osteochondral defects of the talus were accessed. The outcomes of interest were visual analog scale (VAS) score for pain, American Orthopaedic Foot and Ankle Society (AOFAS) score, and Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Data concerning the rates of failure and revision surgery were also collected. Continuous data were analyzed using the mean difference (MD), whereas binary data were evaluated with the odds ratio (OR) effect measure., Results: Data from 40 studies (1174 procedures) with a mean follow-up of 46.5 ± 25 months were retrieved. There was comparability concerning the length of follow-up, male to female ratio, mean age, body mass index, defect size, VAS score, and AOFAS score ( P > .1) between the groups at baseline. At the last follow-up, the MOCART (MD, 10.5; P = .04) and AOFAS (MD, 4.8; P = .04) scores were better in the autograft group. The VAS score was similar between the 2 groups ( P = .4). At the last follow-up, autografts demonstrated lower rate of revision surgery (OR, 7.2; P < .0001) and failure (OR, 5.1; P < .0001)., Conclusion: Based on the main findings of the present systematic review, talar osteochondral transplant using allografts was associated with higher rates of failure and revision compared with autografts at midterm follow-up.

Background: Various cell-free scaffolds are already in use for the treatment of osteochondral defects (OCDs); however, a gold standard material has not yet been defined., Purpose: This study compared the macroscopic, histological, and scanning electron microscopy (SEM) characteristics of Chondro-Gide (CG), MaioRegen (MA), and poly-d,l-lactide-co-caprolactone (PLCL) cell-free scaffolds enhanced with small-diameter microfractures (SDMs) for OCDs in a rabbit model., Study Design: Controlled laboratory study., Methods: In total, 54 knees from 27 rabbits were used in this study. Three rabbits were sacrificed at the beginning of the study to form an intact cartilage control group (group IC). An OCD model was created at the center of the trochlea, and SDMs were generated in 24 rabbits. Rabbits with OCDs were divided into 4 groups (n = 12 knees per group) according to the cell-free scaffold applied: CG (group CG), MA (group MA), PLCL (group PLCL), and a control group (group SDM). Half of the rabbits were sacrificed at 1 month after treatment, while the other half were sacrificed at 3 months after treatment. Healed cartilage was evaluated macroscopically (using International Cartilage Regeneration & Joint Preservation Society [ICRS] classification criteria) and histopathologically (using modified O'Driscoll scores and collagen staining). Additionally, cell-free scaffold morphologies were compared using SEM analysis., Results: ICRS and modified O'Driscoll classification and staining with collagen type 1 and type 2 demonstrated significant differences among groups at both 1 and 3 months after treatment ( P < .05). The histological characteristics of the group IC samples were superior to those of all other groups, except group PLCL, at 3 months after treatment ( P < .05). In addition, the histological properties of group PLCL samples were superior to those of group SDM samples at both 1 and 3 months after treatment in terms of the modified O'Driscoll scores and type 1 collagen staining ( P < .05). Concerning type 2 collagen staining intensity, the groups were ranked from highest to lowest at 3 months after treatment as follows: group PLCL (30.3 ± 2.6) > group MA (26.6 ± 1.2) > group CG (23.3 ± 2.3) > group SDM (18.9 ± 0.9)., Conclusion: OCDs treated with enhanced SDM using cell-free PLCL scaffolds had superior histopathological and microenvironmental properties, more hyaline cartilage, and more type 2 collagen compared with those treated using CG or MA scaffolds., Clinical Relevance: OCDs treated with PLCL cell-free scaffolds may have superior histopathological properties and contain more type 2 collagen than do OCDs treated with CG or MA cell-free scaffolds.

Background: Hemiarthroplasty using a polyvinyl alcohol (PVA) hydrogel synthetic implant has been suggested as a good alternative to arthrodesis for the treatment of hallux rigidus. However, failure rates as high as 20% have been recorded., Purpose: To characterize the pathological processes in bone, cartilage, and the synovial membrane after PVA hemiarthroplasty in an ovine model with 6 months of follow-up., Study Design: Controlled laboratory study., Methods: A unilateral osteochondral defect (8-mm diameter × 10-mm depth) was made in the medial femoral condyle in 6 sheep. Animals were randomized to receive a PVA implant (n = 4) or to have an empty defect (n = 2) and were monitored for 6 months. Patellofemoral radiographs were obtained at monthly intervals, and quantitative computed tomography was performed at the end of the study. After death, the joints were macroscopically evaluated and scored. Osteochondral and synovial membrane histological findings were assessed using modified Osteoarthritis Research Society International (OARSI) and aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) scoring systems. Immunohistochemistry using Iba1 was performed to evaluate activated macrophage infiltration., Results: Overall, 2 sheep with PVA implants were euthanized at 1 and 5 months because of uncontrollable pain and lameness (failed implants). Quantitative computed tomography showed that sheep with failed implants had 2.1-fold more osteolysis than those with successful implants. The sheep with failed implants had osteoarthritis with extensive glycosaminoglycan loss and cartilage fibrillation of the condyle and opposing tibial surface on histological examination. A foreign body reaction with severe chronic lymphoplasmacytic and granulomatous inflammation with giant cells was detected surrounding the implant. The synovial membrane ALVAL score was 9 of 19 and 14 of 19 in failed implants with synovial hyperplasia and lymphoplasmacytic and macrophage infiltration. In contrast, the synovial membrane in successful implants and empty defects was normal (ALVAL score = 0/19). Immunolabeling for Iba1 in failed implants confirmed extensive and dense macrophage infiltration within the condyle and synovial membrane, with the highest immunoreactive score (9/9)., Conclusion: PVA hydrogel implants had a 50% failure rate with uncontrollable pain, severe osteolysis, inflammation, and foreign body reactions., Clinical Relevance: The failure rate and pathological characteristics of the PVA implants suggest that their use should not be continued in human patients without further in vivo safety studies.

Level of Evidence : Level V, expert opinion.

Background: The management of adolescents with acute first-time patellar dislocation with an associated loose body remains a debated topic. The rate of recurrent dislocation in these patients may be up to 61% if the medial patellofemoral ligament (MPFL) is repaired or not addressed surgically. To our knowledge, a prospective evaluation of MPFL reconstruction for adolescents with acute first-time patellar dislocation with an associated chondral or osteochondral loose body has not been previously performed., Purpose/hypothesis: The purpose of this study was to analyze patients with a first-time patellar dislocation who required surgery for a loose body, comparing those who underwent MPFL repair or no treatment with those who underwent MPFL reconstruction during the index procedure. The hypothesis was that performing MPFL reconstruction would reduce the rate of recurrent instability and improve patient-reported outcomes compared with MPFL repair or no treatment. A secondary objective was to report outcomes of those patients who underwent reconstruction versus those who did not., Study Design: Case series; Level of evidence, 4., Methods: This was a prospective analysis of adolescents treated with MPFL reconstruction for acute first-time patellar dislocation with associated loose bodies between 2015 and 2017 at a single pediatric level 1 trauma center with minimum 2-year follow-up. Retrospective analysis was previously performed for a similar cohort of adolescents treated with MPFL repair or no treatment. Patient characteristic data, radiographic measurements, and surgical variables were compared. Primary outcome measures included recurrent subluxation or dislocation and the need for further stabilization procedures. Secondary outcomes included Kujala score, Single Assessment Numeric Evaluation score, patient satisfaction, and ability to return to sport., Results: A total of 76 patients were included, 30 in the MPFL reconstruction cohort and 46 in the MPFL repair or no-treatment cohort. The only difference noted in patient characteristic, radiographic, or surgical variables was a smaller Insall-Salvati ratio in the reconstruction group (1.29 vs 1.42; P = .011). Compared with MPFL repair or no treatment, MPFL reconstruction was associated with less recurrent instability (10.0% vs 58.7%; P < .001), fewer secondary procedures (6.7% vs 47.8%; P < .001), and more frequent return to sports (66.7% vs 39.1%; P = .003). No differences in patient-reported outcomes were noted., Conclusion: Performing concomitant MPFL reconstruction in adolescents with first-time patellar dislocation and an intra-articular loose body results in a 5-fold reduction in recurrent instability, reduces the need for subsequent surgery, and improves patients' ability to return to sports compared with repairing or not treating the MPFL.

Background: Ultrapurified alginate (UPAL) gel implantation has been demonstrated as effective in cartilage repair for osteochondral defects; however, cell transplantation within UPAL gels would be required to treat larger defects., Hypothesis: The combination of UPAL gel and bone marrow aspirate concentrate (BMAC) would enhance cartilage repair and subchondral bone repair for large osteochondral defects., Study Design: Controlled laboratory study., Methods: A total of 104 osteochondral defects (1 defect per knee) of 52 rabbits were randomly divided into 4 groups (26 defects per group): defects without any treatment (Defect group), defects treated using UPAL gel alone (UPAL group), defects treated using UPAL gel containing allogenic bone marrow mesenchymal stromal cells (UPAL-MSC group), and defects treated using UPAL gel containing BMAC (UPAL-BMAC group). At 4 and 16 weeks postoperatively, macroscopic and histologic evaluations and measurements of repaired subchondral bone volumes of reparative tissues were performed. Collagen orientation and mechanical properties of the reparative tissue were assessed at 16 weeks., Results: The defects in the UPAL-BMAC group were repaired with hyaline-like cartilage with well-organized collagen structures. The histologic scores at 4 weeks were significantly higher in the UPAL-BMAC group (16.9 ± 2.0) than in the Defect group (4.7 ± 1.9; P < .05), the UPAL group (10.0 ± 3.3; P < .05), and the UPAL-MSC group (12.2 ± 2.9; P < .05). At 16 weeks, the score in the UPAL-BMAC group (24.4 ± 1.7) was significantly higher than those in the Defect group (9.0 ± 3.7; P < .05), the UPAL group (14.2 ± 3.9; P < .05), and the UPAL-MSC group (16.3 ± 3.6; P < .05). At 4 and 16 weeks, the macroscopic evaluations were significantly superior in the UPAL-BMAC group compared with the other groups, and the values of repaired subchondral bone volumes in the UPAL-BMAC group were significantly higher than those in the Defect and UPAL groups. The mechanical properties of the reparative tissues were significantly better in the UPAL-BMAC group than in the other groups., Conclusion: The implantation of UPAL gel containing BMAC-enhanced hyaline-like cartilage repair and subchondral bone repair of osteochondral defects in a rabbit knee model., Clinical Relevance: These data support the potential clinical application of 1-step treatment for large osteochondral defects using biomaterial implantation with cell transplantation.

Background: Long-term outcomes of current clinical interventions for osteochondral defect are less than satisfactory. One possible reason is an ignorance of the interface structure between cartilage and subchondral bone, the calcified cartilage zone (CCZ). However, the importance of natural CCZ in osteochondral defects has not been directly described., Purpose: To explore the feasibility of fabricating trilayer scaffold containing natural CCZ for osteochondral defects and the role of CCZ in the repair process., Study Design: Controlled laboratory study., Methods: The scaffold was prepared by cross-linking lyophilized type II collagen sponge and acellular normal pig subchondral bone with or without natural CCZ. Autologous bone marrow stem cells (BMSCs) of minipig were mixed with type II collagen gel and injected into the cartilage layer of the scaffold before operation. Thirty minipigs were randomly divided into CCZ (n = 10), non-CCZ (n = 10), and blank control (n = 10) groups. An 8 mm-diameter full-thickness osteochondral defect was created on the trochlear surface, and scaffold containing BMSCs was transplanted into the defect according to grouping requirements. At 12 and 24 weeks postoperatively, specimens were assessed by macroscopic observation, magnetic resonance imaging examination, and histological observations (hematoxylin and eosin, Safranin O-fast green, type II collagen immunohistochemical, and Sirius red staining). Semiquantitative cartilage repair scoring was conducted using the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) system and the O'Driscoll repaired cartilage value system., Results: The defects in the blank control and non-CCZ groups were filled with fibrous tissue, while the cartilage layer of the CCZ group was mainly repaired by hyaline cartilage at 24 weeks postoperatively. The superior repair outcome of the CCZ group was confirmed by MOCART and O'Driscoll score., Conclusion: The trilayer scaffold containing natural CCZ obtained the best repair effect compared with the non-CCZ scaffold and the blank control, indicating the importance of the CCZ in osteochondral tissue engineering., Clinical Relevance: This study demonstrates the necessity to reconstruct CCZ in clinical osteochondral defect repair and provides a possible strategy for osteochondral tissue engineering.

Background: Bone marrow stimulation (BMS) via microfracture historically has been a first-line treatment for articular cartilage lesions. However, BMS has become less favorable because of resulting fibrocartilage formation. Previous studies have shown that angiogenesis blockade promotes cartilage repair. Bevacizumab is a Food and Drug Administration-approved medication used clinically to prevent angiogenesis., Hypothesis: The intra-articular injection of bevacizumab would prevent angiogenesis after BMS and lead to improved cartilage repair with more hyaline-like cartilage., Study Design: Controlled laboratory study., Methods: The dose of bevacizumab was first optimized in a rabbit osteochondral defect model with BMS. Then, 48 rabbits (n = 8/group/time point) were divided into 3 groups: osteochondral defect (defect), osteochondral defect + BMS (BMS group), and osteochondral defect + BMS + bevacizumab intra-articular injection (bevacizumab group). Rabbits were sacrificed at either 6 or 12 weeks after surgery. Three-dimensional (3D) micro-computed tomography (microCT), macroscope score, modified O'Driscoll histology scores, collagen type 2, Herovici staining, and hematoxylin and eosin staining were performed. Angiogenesis markers were also evaluated., Results: The intra-articular dose of 12.5 mg/0.5 mL bevacizumab was found to be effective without deleteriously affecting the subchondral bone. Intra-articular injection of bevacizumab resulted in significantly improved cartilage repair for the bevacizumab group compared with the BMS or the defect group based on 3D microCT, the macroscope score (both P < .05), the modified O'Driscoll histology score ( P = .0034 and P = .019 vs defect and BMS groups, respectively), collagen type 2, Herovici staining, and hematoxylin and eosin staining at 6 weeks. Cartilage in the bevacizumab group had significantly more hyaline cartilage than did that in other groups. At 12 weeks, the cartilage layer regenerated in all groups; however, the bevacizumab group showed more hyaline-like morphology, as demonstrated by microCT, histology scores ( P < .001 and .0225 vs defect and BMS groups, respectively), histology, and immunohistochemistry. The bevacizumab injection did not significantly change mRNA expressions of smooth muscle actin, vascular endothelial growth factor, or hypoxia-inducible factor-1 alpha., Conclusion: Intra-articular injection of bevacizumab significantly enhanced the quality and quantity of hyaline-like cartilage after BMS in a rabbit model. Future large-animal and human studies are necessary to evaluate the clinical effect of this therapy, which may lead to improved BMS outcomes and thus the durability of the regenerated cartilage., Clinical Relevance: The use of bevacizumab may be an important clinical adjunct to improve BMS-mediated cartilage repair.

Cryopreserved umbilical cord (UC) allografts have been shown to promote postoperative wound healing by suppressing inflammation and reducing scar formation. The purpose of this study was to determine whether adjunctive use of UC may improve clinical and functional outcomes following arthroscopic repair of talar osteochondral defects (OCDs). A total of 10 patients with talar OCDs that failed nonoperative treatment were enrolled in this single-center, prospective, pilot study. Clinical and functional outcomes were assessed using the Ankle Osteoarthritis Scale (AOS), Foot and Ankle Ability Measure, and Visual Analog Scale (VAS) pain scale at 6, 12, 24, and 52 weeks postoperatively. Results showed a consistent improvement in all outcome measures. VAS pain scores significantly improved from 4.2 ± 2.9 to 1.3 ± 2.2 at 52 weeks (P = .015). AOS difficulty and pain scores nonsignificantly improved from 27.0 ± 24.6 and 33.1 ± 28.3 at baseline to 15.3 ± 20.5 and 14.8 ± 18.7 at 52 weeks, respectively. The clinical outcome improvement was accompanied by significant reduction in OCD defect size and associated bone marrow lesion. This pilot study suggests that adjunctive use of UC during arthroscopic repair of talar OCD may lead to clinical and functional improvement. Levels of Evidence: Level II: Prospective Cohort Study.

Background: Osteoarthritis is the leading cause of disability worldwide; cartilage degeneration and defects are the central features. Significant progress in tissue engineering holds promise to regenerate damaged cartilage tissue. However, a formidable challenge is to develop a 3-dimensional (3D) tissue construct that can regulate local immune environment to facilitate the intrinsic osteochondral regeneration., Purpose: To evaluate efficacy of a 3D-printed decellularized cartilage extracellular matrix (ECM) and polyethylene glycol diacrylate (PEGDA) integrated novel scaffold (PEGDA/ECM) together with the natural compound honokiol (Hon) for regenerating osteochondral defect., Study Design: Controlled laboratory study., Methods: We used a stereolithography-based 3D printer for PEGDA/ECM bioprinting. A total of 36 Sprague-Dawley rats with cylindrical osteochondral defect in the trochlear groove of the femur were randomly assigned into 3 different treatments: no scaffold implantation (Defect group), 3D printed PEGDA/ECM scaffold alone (PEGDA/ECM group), or Hon suspended in a 3D-printed PEGDA/ECM scaffold (PEGDA/ECM/Hon group). 12 rats that underwent only medial parapatellar incision surgery were used as normal controls. The femur specimens were postoperatively harvested at 4 and 8 weeks for gross, micro-CT, and histological evaluations. The efficacy of PEGDA/ECM/Hon scaffold on the release of proinflammatory cytokines from the macrophages stimulated by lipopolysaccharide (LPS) was evaluated in-vitro., Results: In vitro results determined that PEGDA/ECM/Hon scaffold could suppress the release of proinflammatory cytokines from macrophages that were stimulated by LPS. Macroscopic images showed that the PEGDA/ECM/Hon group had significantly higher ICRS scoring than that of defect and PEGDA/ECM groups. Micro-CT evaluation demonstrated that much more bony tissue was formed in the defect sites implanted with the PEGDA/ECM scaffold or PEGDA/ECM/Hon scaffold compared with the untreated defects. Histological analysis showed that the PEGDA/ECM/Hon group had a significant enhancement in osteochondral regeneration at 4 and 8 weeks after surgery in comparison with the ECM/PEGDA or defect group., Conclusion: This study demonstrated that 3D printing of PEGDA/ECM hydrogel incorporating the anti-inflammatory phytomolecule honokiol could provide a promising scaffold for osteochondral defect repair.

Background: While smaller talar dome osteochondral lesions (OCLs) are successfully treated with bone marrow stimulation techniques, the optimal treatment for large or cystic OCLs remains controversial. This study tested the hypothesis that transferring structural autograft bone from the distal tibia to the talus for large or cystic OCLs improves pain and function., Methods: Thirty-two patients with large or cystic OCLs underwent structural bone grafting from the ipsilateral distal tibia to the talar dome. Patients were assessed with subjective patient-centered tools and objective clinical outcomes. Average age was 48.6 ± 14.9 years, and average follow-up was 19.5 ± 13.3 months. Average lesion area was 86.2 ± 23.5 mm 2 , and average depth was 8.4 ± 3.0mm., Results: At final follow-up, improvement compared to preoperative scores was seen in American Orthopaedic Foot & Ankle Society (65.4 ± 21.2 to 86.9 ± 15.0, P < .05), Foot Function Index (48.9 ± 20.8 to 21.1 ± 18.9, P < .05), visual analog scale for pain (4.7 ± 3.0 to 1.4 ± 1.5, P < .05), and Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (40.4 ± 5.4 to 45.5 ± 7.4, P < .05) scores. There was no improvement in PROMIS pain interference (54.7 ± 18.1 to 52.4 ± 7.3, P > .05). Satisfaction with surgery was 8.4 ± 1.3/10, and 96% of patients would have the procedure again. Ninety-four percent of patients returned to work and/or play. One patient had a deep vein thrombosis 6 weeks postoperatively, and 1 patient underwent ankle fusion at 18 months postoperatively., Conclusion: This study demonstrates that structural bone graft harvested from the distal tibia transferred to the talus was a safe and effective treatment for large and cystic OCLs. Outcomes compare favorably to other described techniques for treatment of these injuries., Level of Evidence: Level IV, case series.

Background: Human amniotic mesenchymal stem cells (hAMSCs) are being widely applied in various fields. Therefore, hAMSCs represent a promising candidate to facilitate cartilage regeneration. Nonetheless, no studies have investigated the application of hAMSC sheets to repair cartilage defects in vivo., Purpose: To evaluate hAMSC sheets encapsulating cartilage particles to promote repair of rabbit osteochondral defects., Study Design: Controlled laboratory study., Methods: hAMSC sheets were constructed with passage 3 hAMSCs. The phenotypic and structural characteristics of hAMSC sheets were evaluated by flow cytometry and scanning electron microscopy, respectively. The potential for chondrogenic differentiation of hAMSC sheets was assessed by cartilage-specific marker staining, immunohistochemistry, and mRNA and protein expression (SOX9, COLII, and ACAN). Osteochondral defects (diameter, 3.5 mm; depth, 3 mm) were created in the left patellar grooves of 20 New Zealand White rabbits (female or male). The defects were treated with hAMSC sheet/cartilage particles (n = 5), cartilage particles (n = 5), hAMSC sheets (n = 5), or fibrin glue (n = 5). Macroscopic and histological evaluations of the regenerated tissue were conducted after 3 months. The survival time and differentiation of transplanted hAMSCs in the defect area were evaluated by immunofluorescence., Results: hAMSC sheets had a multilayered structure, with cells stacked layer by layer. Importantly, hAMSC sheets highly expressed phenotypic markers of mesenchymal stem cells. Cartilage-specific marker staining and immunohistochemistry were positive, and mRNA and protein expression was higher in the chondrogenically induced hAMSC sheet group than in the hAMSC sheet group ( P < .05). hAMSC sheet/cartilage particles formed a large amount of hyaline-like cartilage in the defect area. In addition, macroscopic and histological scores were significantly higher than those in the other groups. Integration with surrounding normal cartilage and subchondral bone regeneration in the hAMSC sheet/cartilage particles group were better when compared with the other groups. A large number of human nuclear-specific antigen-positive cells were observed in the defect area of hAMSC sheet/cartilage particles and hAMSC sheet groups. Moreover, some positive cells expressed SOX9., Conclusion: hAMSC sheets encapsulating cartilage particles facilitate osteochondral defect repair., Clinical Relevance: Delivery of cells in the form of a cell sheet in conjunction with cartilage particles provides a novel approach for cell-based cartilage regeneration.

Background: The treatment of osteochondral defects (OCDs) constitutes a major problem for orthopaedic surgeons. The altered mechanics and the cell types, with associated soluble factors derived from the exposed subchondral bone, are likely responsible for the mechanically and structurally inferior articular cartilage subsequently obtained as a repair tissue. There is therefore an unmet clinical need for bioresponsive biomaterials that allow cell delivery, reduce cell infiltration from the bone marrow, and support chondrogenesis in the presence of joint mechanical loading., Purpose: To develop a cell-laden injectable biomaterial, with bioadhesive properties, low cell invasion, and good mechanoresilience, in which simulated joint loading could induce tissue maturation through the production and activation of transforming growth factor beta 1 (TGF-β1)., Study Design: Controlled laboratory study., Methods: Human bone marrow-derived mesenchymal stromal/stem cells were encapsulated in tyramine-modified hyaluronic acid (HA-Tyr) hydrogels, with crosslinking initiated by the addition of horseradish peroxidase (HRP) and various concentrations of hydrogen peroxide (H 2 O 2 ; 0.3-2 mM). Cytocompatibility and biomechanical and adhesive properties were analyzed by live/dead staining, rheology, and push-out test, respectively. For multiaxial loading, cell-laden hydrogels were subjected to 10% compression superimposed onto a 0.5-N preload and shear loading (±25°) at 1 Hz for 1 hour per day and 5 times a week for 4 weeks. TGF-β1 production and activation were measured by enzyme-linked immunosorbent assay (ELISA)., Results: The viscoelastic properties of the cell-laden HA-Tyr hydrogels, as crosslinked with different ratios of HRP and H 2 O 2 , were demonstrated for a range of cell densities and HRP/H 2 O 2 concentrations. In the absence of serum supplementation, cell invasion into HA-Tyr hydrogels was minimal to absent. The bonding strength of HA-Tyr to articular cartilage compared favorably with clinically used fibrin gel., Conclusion: HA-Tyr hydrogels can be mechanically conditioned to induce activation of endogenous TGF-b1 produced by the embedded cells. HA-Tyr hydrogels function as cell carriers supporting biomechanically induced production and activation of TGF-β1 and as bioadhesive materials with low cell invasion, suggesting that they hold promise as a novel biomaterial for OCD repair strategies., Clinical Relevance: Leveraging physiological joint mechanics to support chondrogenic graft maturation in an optimized mechanosensitive hydrogel in the absence of exogenous growth factors is of highest interest for OCD repair.

Background: It is unclear whether chondral fragments without bone have the potential to heal after fixation. Controversy exists and opinions differ regarding the optimal treatment of chondral defects after pure chondral fracture., Purpose: To determine clinical and radiographic outcomes after internal fixation of traumatic chondral fragments repaired to bone in the knee., Study Design: Case series; Level of evidence, 4., Methods: A retrospective clinical and radiographic evaluation of 10 male patients with a mean age of 14.6 years (range, 10-25 years) at the time of surgery was performed. Eight of 10 patients were skeletally immature. Patients were selected by operating surgeons per the presence of a large displaced pure chondral fragment on magnetic resonance imaging and confirmed on intraoperative inspection. All patients had a diagnosed traumatic displaced pure chondral fracture of the knee (without bone) and underwent internal fixation with minimum 1-year follow-up. Validated patient-reported and surgeon-measured outcomes were collected pre- and postoperatively. All patients were evaluated at a mean 56 months postoperatively., Results: At surgery, the mean defect size that was primarily repaired with the displaced chondral fragment was 1.9 × 2.0 cm. With minimum 1-year follow-up, there were no clinical failures. All 8 patients who had subsequent magnetic resonance imaging follow-up had radiographic evidence of complete healing of the chondral fragment back to bone. At a mean follow-up of 56 months (range, 13-171 months; median, 36 months), patients had a mean International Knee Documentation Committee score of 94.74 (range, 87.4-100), a mean Marx Activity Scale score of 14.4 (range, 8-16), and a mean Tegner Activity Scale score of 7 (range, 5-9). At final follow-up, all patients except 1 returned to sports., Conclusion: The treatment of large traumatic chondral fragments is controversial. In this select series of 10 young patients who underwent primary repair with internal fixation, there were no failures clinically. Patients demonstrated excellent short-term clinical and radiographic results after fixation of these relatively large chondral fragments in the knee.

Background: Recruitment of endogenous stem cells has been considered an alternative to cell injection/implantation in articular cartilage repair., Purpose: (1) To develop a cartilage tissue-engineering scaffold with clinically available biomaterials and functionalize the scaffold with an aptamer (Apt19s) that specifically recognizes pluripotent stem cells. (2) To determine whether this scaffold could recruit joint-resident mesenchymal stem cells (MSCs) when implanted into an osteochondral defect in a rabbit model and to examine the effects of cartilage regeneration., Study Design: Controlled laboratory study., Methods: The reinforced scaffold was fabricated by embedding a silk fibroin sponge into silk fibroin/hyaluronic acid-tyramine hydrogel and characterized in vitro. A cylindrical osteochondral defect (3.2 mm wide × 4 mm deep) was created in the trochlear grooves of rabbit knees. The rabbits were randomly assigned into 3 groups: Apt19s-functionalized scaffold group, scaffold-only group, and control group. Animals were sacrificed at 6 and 12 weeks after transplantation. Repaired tissues were evaluated via gross examination, histologic examination, and immunohistochemistry., Results: In vitro, this aptamer-functionalized scaffold could recruit bone marrow-derived MSCs and support cell adhesion. In vivo, the aptamer-functionalized scaffold enhanced cell homing in comparison with the aptamer-free scaffold. The aptamer-functionalized scaffold group also exhibited superior cartilage restoration when compared with the scaffold-only group and the control group., Conclusion: The Apt19s-functionalized scaffold exhibited the ability to recruit MSCs both in vitro and in vivo and achieved a better outcome of cartilage repair than the scaffold only or control in an osteochondral defect model., Clinical Relevance: The findings demonstrate a promising strategy of using aptamer-functionalized bioscaffolds for restoration of chondral/osteochondral defects via aptamer-introduced homing of MSCs.

Background: Autologous chondrocyte implantation, which uses passaged chondrocytes, commonly leads to the formation of fibrocartilage. When chondrocytes are passaged to increase cell numbers, they lose their phenotype and ability to form hyaline cartilage. The use of transforming growth factor β (TGFβ) to redifferentiate passaged chondrocytes has been validated in vitro; however, it is unknown if redifferentiated chondrocytes will enhance defect repair when implanted in vivo. Furthermore, fibrin gel is used in orthopaedic surgery as a fixative and scaffold and could be an appropriate carrier to enhance retention of cells in the repair site., Purpose: To investigate if passaged redifferentiated chondrocytes in fibrin gel have the ability to form cartilage tissue and if these redifferentiated cells will enhance the formation of hyaline cartilage in vivo when implanted into critical-size osteochondral defects., Study Design: Controlled laboratory study., Methods: Rabbit and human chondrocytes were serially passaged twice in monolayer culture. Twice-passaged cells were used directly (dedifferentiated) or redifferentiated in high-density culture with TGFβ3. Dedifferentiated or redifferentiated cells were mixed with fibrin gel to form fibrin clots, which were cultured in vitro to assess the use of fibrin gel as a scaffold or implanted in vivo in a critical-size osteochondral defect in New Zealand White rabbit knee joints. Rabbits were sacrificed 6 weeks after implantation, and tissues were assessed histologically and by immunohistochemistry., Results: Redifferentiation of passaged chondrocytes by means of 3-dimensional culture in the presence of TGFβ3 improved the formation of cartilaginous tissues in vitro, and culture in fibrin gel did not affect the cell phenotype. Implantation of dedifferentiated cells in vivo resulted in fibrocartilaginous repair tissues. Redifferentiated chondrocyte implants resulted in granulation tissues containing the hyaline cartilage marker collagen type 2., Conclusion: Redifferentiated chondrocytes will maintain their chondrogenic differentiation in fibrin clots. Implanted redifferentiated chondrocytes show a different reparative response than dedifferentiated chondrocytes and do not appear to enhance repair at an early time point. Another study of longer duration is required to assess tissue maturation over time., Clinical Relevance: Redifferentiation of passaged chondrocytes with TGFβ3 before implantation does not improve defect repair in the first 6 weeks.

Background: Multiple ankle pathologies have been found to coexist with chronic lateral ankle ligament instability, but their prevalence varies widely in the literature. The purpose of this study is to reexamine the prevalence of these associated pathologies and to determine their impact on reoperation rate., Methods: We retrospectively reviewed 382 cases of lateral ankle ligament repair/reconstruction between June 2006 and November 2016. Patient charts and radiograph reports were examined for the presence of any associated foot and ankle pathologies as well as clinical course. The effect of copathologies on reoperation rate was examined using binary logistic regression and the χ 2 test., Results: We included a total of 99 cases. Copathologies included peroneal pathology (75/99, 75.8%), ankle impingement (40/99, 40.4%), and osteochondral lesion of the talus (17/99, 17.2%); 36.4% (36/99) had a low-lying muscle belly of peroneus brevis. The total reoperation rate was 12/92 (13.1%). It was lower in cases with peroneal pathology (8.7% vs 27.5%, P = .032)., Conclusion: Peroneal pathology, ankle impingement, and osteochondral lesions were the most common associated copathologies in surgical patients with chronic lateral ankle ligament instability. The presence of peroneal pathology may lead to fewer reoperations, possibly as a result of a more comprehensive first-time surgical approach. Level of Evidence: Level III: Retrospective cohort.

Background: Osteochondral allograft transplantation (OCA) is a successful knee joint preservation technique; however, the effects of defect size and defect size:condyle ratio (DSCR) are poorly understood., Purpose: To quantify clinical outcomes of isolated OCA of the knee based on defect size and DSCR., Study Design: Cohort study; Level of evidence, 3., Methods: Data from patients who underwent OCA of the knee without major concomitant procedures by a single surgeon were analyzed at a minimum follow-up of 2 years. Osteochondral defect size was measured intraoperatively, and femoral condyle size was measured with preoperative imaging. Patient-reported outcomes, reoperations, and survival rates were analyzed per defect size and DSCR, comparing males and females and patients <40 and ≥40 years old., Results: Sixty-eight patients were included, of whom 57% were male (mean ± SD: age, 34.5 ± 10.3 years; follow-up, 5.2 ± 2.6 years). Mean osteochondral defect size and DSCR were 3.48 ± 1.72 cm 2 and 0.2 ± 0.1, respectively. Defect size was larger among males as compared with females (3.97 ± 1.71 cm 2 vs 2.81 ± 1.16 cm 2 , P = .005), while DSCRs were not significantly different between sexes ( P = .609). The cohort as a whole demonstrated improvements in the following scores: Lysholm, International Knee Documentation Committee, Knee injury and Osteoarthritis Outcome Score, Western Ontario and McMaster Universities Osteoarthritis Index, and 12-Item Short Form Health Survey Physical ( P < .05). There were 27 reoperations (39.7%) at a mean of 2.5 ± 1.92 years and 8 failures (11.8%) at a mean of 2.62 ± 1.3 years. Mean DCSR was higher among patients with graft failure (0.26 ± 0.20 vs 0.19 ± 0.07, P = .049). After stratification by age, failures among patients ≥40 years old were associated with a larger defect size (mean 5.37 ± 3.50 cm 2 vs 3.22 ± 1.32 cm 2 , P = .03) and higher DSCR (mean 0.30 ± 0.25 vs 0.19 ± 0.06, P = .05) when compared with nonfailures. Failures among patients <40 years old were not significantly associated with defect size or DSCR ( P > .05) as compared with nonfailures., Conclusion: Patients undergoing isolated OCA transplantation demonstrated significant clinical improvements and a graft survival of 88.2% at 5.2 years. Failures overall were associated with a larger DSCR, and failures among patients ≥40 years old with a larger DSCR and larger defect size. Increasing defect size among males was positively correlated with some improved outcomes, although this was not maintained in analysis of the DSCR, suggesting similar prognosis after OCA regardless of sex., Clinical Relevance: Failed osteochondral allografts are associated with larger defect sizes and defect:condyle ratios in this study, providing additional information to surgeons for appropriate patient consultation.

Purpose: Choosing a therapeutic cell source for osteochondral repair remains a challenge. The present study investigated coculturing mesenchymal stem cells (MSCs) from different sources to provide an improved therapeutic cell option for osteochondral repair., Methods: Dutch and Japanese white rabbits were used in this study, the first for isolating MSCs and the second for creating an osteochondral model in the medial femoral condyle. The 26 rabbit knees were divided randomly into four groups: control ( n = 6), bone marrow-derived MSCs (BMSCs) ( n = 7), synovial tissue MSCs (SMSCs) ( n = 7), and cocultured MSCs ( n = 6). Tissue repair was assessed using the Fortier scale, and colony-forming assay was performed., Results: At different cell densities, cocultured and SMSCs formed larger colonies than BMSCs, indicating their high proliferative potential. After 2 months, complete filling of the defect with smooth surface regularity was detected in the cocultured MSC group, although there was no significant difference among the therapeutic groups macroscopically. Also, tissue repair was histologically better in the cocultured MSC group than in the control and SMSC groups, due to repair of the subchondral bone and coverage with hyaline cartilage. Additionally, toluidine blue and collagen-II staining intensity in the repaired tissue was better in the cocultured MSC group than in the remaining groups., Conclusion: Our results suggest that cocultured MSCs are a suitable option for the regeneration capability of osteochondral defects due to their enhanced osteochondrogenic potential.

Background: First-time patellar dislocation with an associated chondral or osteochondral loose body is typically treated operatively to address the loose fragment. The incidence of recurrent instability in this patient population if the medial patellofemoral ligament (MPFL) is not reconstructed is unknown., Purpose: To determine the recurrent instability rate in patients undergoing surgery for patellar instability with chondral or osteochondral loose bodies, as well as to identify and stratify risk factors for recurrent instability., Study Design: Case series; Level of evidence, 4., Methods: This was a retrospective analysis of adolescent patients treated operatively for acute patellar dislocation with associated chondral or osteochondral loose bodies between 2010 and 2016 at a single pediatric level I trauma center with minimum 2-year follow-up. Potential demographic, injury-related, radiographic, and surgical risk factors were recorded. The primary outcome variable was recurrent subluxation and/or dislocation. Secondary outcome variables included need for additional procedures, Kujala score, Single Assessment Numerical Evaluation (SANE) score, and patient satisfaction., Results: Forty-one patients were included. In total, 61% experienced recurrent instability at a mean follow-up of 4.1 years and 39% required subsequent MPFL reconstruction. Tibial tubercle-trochlear groove (TT-TG) distance greater than 15 mm was a risk factor for recurrent instability ( P = .03). Patients with TT-TG distance greater than 15 mm and greater than 20 mm had recurrent instability rates of 75% and 86%, respectively. MPFL repair did not reduce the rate of recurrent instability ( P = .87). Recurrent instability was associated with significantly worse mean Kujala (93.9 vs 83.0; P = .01), SANE (88.9 vs 73.1; P = .01), and patient satisfaction scores (9.4 vs 7.3; P = .002)., Conclusion: If the MPFL is not reconstructed during index loose body treatment, children have a 61% recurrent instability rate. Patients with TT-TG distance greater than 15 mm, and particularly greater than 20 mm, are at highest risk for recurrent instability.

Background: Engraftment and longevity of transplanted cells are crucial for stem cell-based cartilage treatment., Purpose: To determine whether cultured spherical cell masses of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) could improve engraftment at defect sites and to examine their corresponding effects on osteochondral regeneration., Study Design: Controlled laboratory study., Methods: A cylindrical osteochondral defect (5 mm wide × 5 mm deep) was created in trochlear grooves of rabbit knees. The single-cell type of hBM-MSCs with fibrin glue, the spherical type of hBM-MSCs with fibrin glue, and cell-free fibrin glue (control) were each implanted into osteochondral defect sites. A total of 18 rabbit knees were randomly assigned to 1 of the 3 groups (3 rabbits per group). Animals were sacrificed at 6 and 12 weeks after transplantation. Repaired tissues were evaluated via gross examination, histologic examination, and immunofluorescence analysis., Results: Transplantation with spherical hBM-MSCs exhibited superior overall osteochondral restoration when compared with the single-type group, as evidenced by well-ordered mature collagen fibrils produced during subchondral bone formation in the zonation phenomenon. Immunofluorescence analysis of osteochondral defect areas with human-specific antigen revealed a larger number of mesenchymal stem cells in the spherical-type group than the single cell-type group., Conclusion: Transplantation of spherical hBM-MSCs was better than single cells from monolayer culture in improving osteochondral regeneration., Clinical Relevance: The findings demonstrate a simple strategy for enhancing the potency of stem cells required for restoration of osteochondral defects. Furthermore, this strategy may be implemented with other types of stem/progenitor cell-based therapies.

Background: Treatment of osteochondral talar defects (OCDs) after failed previous surgery is challenging. Promising short-term results have been reported with use of a metal resurfacing inlay implant., Purpose: To evaluate the midterm clinical effectiveness of the metal implant for OCDs of the medial talar dome after failed previous surgery., Study Design: Case series; Level of evidence, 4., Methods: We prospectively studied all patients who met the inclusion criteria and received a metal resurfacing inlay implant between 2007 and 2014. The primary outcome measure was implant survival, as measured by reoperation rate. Secondary outcome measures were numeric rating scales for pain at rest and during walking, running, and stair climbing; the Foot and Ankle Outcome Score (FAOS); the American Orthopaedic Foot and Ankle Society Ankle Hindfoot Scale; the 36-Item Short Form Health Survey (SF-36); return to work and sports; and radiographic evaluation., Results: This study included 38 patients with a mean age of 39 years (SD, ±13 years) and a mean follow-up of 5.1 years (SD, ±1.5 years). Two patients (5%) underwent revision surgery by means of an ankle arthrodesis (2 and 6 years postoperatively). In 8 patients, computed tomography scanning was conducted to assess postoperative complaints. These scans showed impression of the tibial plafond (n = 4), a small tibial cyst (<2.5 mm; n = 1), and cyst formation around the implant screw (n = 4). A total of 21 reoperations were performed, including medial malleolar screw removal (n = 12), arthroscopic removal of bony anterior impingement (n = 7), and calcaneal realignment osteotomy (n = 2). All secondary outcome measures improved significantly, apart from pain at rest, the FAOS symptoms subscale, and the SF-36 mental component scale. The mean time for return to sport was 4.1 months (SD, ±3 months), and 77% of patients resumed sporting activities postoperatively. Only 1 patient did not return to work postoperatively. Radiographs at final follow-up showed cyst formation (n = 2), subchondral periprosthetic radiolucency (n = 2), and non-preexisting joint space narrowing (n = 2)., Conclusion: This study shows that the metal implant is an effective technique when assessed at midterm follow-up for OCDs of the medial talar dome after failed previous surgery.

Background: Focal damage to articular cartilage, also called an osteochondral defect (OCD), can be a cause of pain and decreased range of motion. Recent advancements have led to transplantation techniques using particulated juvenile articular cartilage allograft. This technique has been applied to the first metatarsal head to a very limited degree, with no published results to our knowledge. The aim of this study was to review the clinical results of patients who underwent particulated juvenile cartilage allograft implantation for first metatarsal head OCDs., Methods: We performed a retrospective consecutive case series study. Nine patients, at an average age of 41 years, were treated for symptomatic focal osteochondral defects of the first metatarsal head with particulate cartilage grafting from 2010 to 2016. Patients were contacted by phone to assess interest in returning to the office for follow-up, where weightbearing radiographs of the foot were obtained and a foot examination was performed., Results: At an average follow-up of 3.3 years, 7 of 9 patients reported no pain with recreational activities and no patient required further operations. This patient cohort was physically active, with 6 of 9 listing running as a regular activity. The average overall American Orthopaedic Foot & Ankle Society (AOFAS) Hallux Metatarsophalangeal-Interphalangeal Scale questionnaire score was 85 (maximum 100), AOFAS pain 35.6 (maximum 40), and AOFAS function 40.1 (maximum 45). Patient satisfaction surveys correlated with the AOFAS scores and revealed that 7 of 9 patients were very satisfied with their results, 1 was satisfied, and 1 patient was very dissatisfied., Conclusion: Particulated juvenile cartilage allograft transplantation is a promising treatment option for symptomatic first metatarsophalangeal focal articular cartilage lesions. Further study is needed to demonstrate which lesions respond better to this type of cartilage graft versus traditional marrow-stimulating procedures., Level of Evidence: Level IV, retrospective case series.

We investigated talus and tibial plafond subchondral bone puncture strength based on surface location. Puncture tests of the subchondral bone were performed in 9 equal zones on the articular surface of 12 cadaver specimens aged 49.1 years (range, 36-56 years). Compressive load was applied through a microfracture awl at 2 mm/min. Puncture strength was defined as the first load drop in load-deflection curves. In the talus, zone 1 (215 ± 91 N) and zone 2, the anterior medial and anterior middle zones, had significantly greater puncture strength than zones 7, 8, and 9, the posterior medial, middle, and lateral zones (104 ± 43 N, 115 ± 43 N, and 102 ± 35 N, respectively; P < .001). In the tibial plafond, zone 3, the anterior-lateral zone, and zone 7, the posterior medial zone, had significantly greater strength than zone 8, the posterior middle zone (202 ± 72 N, 206 ± 121 N, and 112 ± 65 N, respectively; P < .001) These results suggest that the subchondral bone is significantly weaker to penetrative force in the posterior region than in the anterior region of the talar dome and of the tibial plafond. These findings may have implications for microfracture awl design and for understanding the complex anatomy and physiology of the ankle joint., Levels of Evidence: Controlled laboratory study.

Background: Traumatic tears of the tibialis posterior (TP) tendon following an ankle sprain are rare. The purpose of this study was to report our case series of TP tendon tears following an ankle sprain., Methods: Patients with persistent TP tendon pain after an ankle sprain were retrospectively identified over a 4-year period and reviewed. A comparison of magnetic resonance imaging (MRI) interpretations by a radiologist and surgeon was made. Patients failing conservative management underwent operative repair of the TP tendon tear and concomitant pathology. Failure of the index surgery was defined as TP tendinosis, which was treated with excision and flexor digitorum longus tendon transfer. Outcomes were measured with the Foot Function Index (FFI) and American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot scores., Results: Thirteen patients were found to have a TP tendon tear following an ankle sprain. The incidence for TP tears with sprains presented to our clinic was 1.04%. MRI identified TP tendon pathology in 4 patients by a radiologist review and in 11 patients by a surgeon review. The most common concomitant pathology was a talar osteochondral defect in 13 of 13 patients and ligament instability in 12 of 13 patients (5/13 lateral, 3/13 medial, 4/13 multidirectional instability). Four of 13 patients failed the index surgery. Of the 9 remaining patients, 4 had clinical follow-up at an average of 4.6 years postoperatively. The average FFI subscale scores were the following: pain, 40.4; disability, 28.9; and activity, 23.6. The average AOFAS hindfoot score was 68.8., Conclusion: Despite being rare, a TP tendon tear should be included in the differential diagnosis for persistent medial-sided pain following an ankle sprain. MRI findings can be subtle. Associated pathology was very common and likely confounded the diagnosis and outcomes. Patients should be counseled on the possibility of poor outcomes and long-term pain., Level of Evidence: Level IV, case series.

Background: Widespread adoption of fresh allograft transplantation remains limited, predominantly by supply issues. To overcome these limitations, a preshaped, cylindrical sterilized and decellularized osteochondral allograft (SDOCA) implant was recently introduced as a clinical treatment option., Purpose: To evaluate functional outcomes and graft survivorship among patients treated with the SDOCA implant for knee cartilage injuries., Study Design: Case series; Level of evidence, 4., Methods: An institutional review board-approved database was used to identify a series of patients with prospectively collected data who had been treated with the SDOCA implant. The surgeries were performed at 2 centers by 2 surgeons. Patient-reported outcomes, magnetic resonance imaging (MRI), and the number and type of reoperations were assessed. Failure was defined as structural damage of the graft diagnosed by arthroscopy or MRI, and any reoperation resulting in removal of the allograft. Patients were evaluated pre- and postoperatively using the Knee injury and Osteoarthritis Outcome Score (KOOS) and Marx Sports Activity Scale. MRI was assessed preoperatively and postoperatively., Results: There were 32 patients with a mean age (±SD) of 35.1 ± 10.6 years; 59% were male. Twenty-three (72%) knees had previous surgery. The mean defect area (±SD) was 2.9 ± 2.0 cm(2), and the mean allograft size was 13.18 ± 2.3 mm (6 grafts ≤9 mm and 59 grafts ≥11 mm). The median number of allografts per knee was 2 (range, 1-5 grafts). Twenty-three of the 32 knees (72%) were considered failures by the definition detailed above. Of these, 14 knees (43%) had further surgery after the index procedure. Implant survivorship was 19.6% at 2 years. The mean follow-up duration was 1.29 years (range, 0.11-2.8 years). KOOS pain, activities of daily living (ADL), sports and recreation (sport/rec), and knee-related quality of life improved significantly from the preoperative visit to latest follow-up. Age was significantly predictive of failure, with a hazard ratio of 1.68 per 1 SD older (95% CI, 1.05-2.68; P = .030). The MOCART (magnetic resonance observation of cartilage repair tissue) feature effusion was the only score to correlate with KOOS (symptoms, pain, ADL, sport/rec)., Conclusion: The SDOCA implant demonstrated a 72% failure rate within the first 2 years of implantation at these 2 institutions., (© 2016 The Author(s).)

Background: Osteochondral defects (OCDs) of the talus usually affect athletic patients. The primary surgical treatment consists of arthroscopic debridement and microfracture. Various possibilities have been suggested to improve the recovery process after debridement and microfracture. A potential solution to obtain this goal is the application of pulsed electromagnetic fields (PEMFs), which stimulate the repair process of bone and cartilage., Hypothesis: The use of PEMFs after arthroscopic debridement and microfracture of an OCD of the talus leads to earlier resumption of sports and an increased number of patients that resume sports., Study Design: Randomized controlled trial; Level of evidence, 1., Methods: A total of 68 patients were randomized to receive either PEMFs (n = 36) or placebo (n = 32) after arthroscopic treatment of an OCD of the talus. The primary outcomes (ie, the number of patients who resumed sports and time to resumption of sports) were analyzed with Kaplan-Meier curves as well as Mann-Whitney U, chi-square, and log-rank tests. Secondary functional outcomes were assessed with questionnaires (American Orthopaedic Foot and Ankle Society ankle-hindfoot score, Foot and Ankle Outcome Score, EuroQol, and numeric rating scales for pain and satisfaction) at multiple time points up to 1-year follow-up. To assess bone repair, computed tomography scans were obtained at 2 weeks and 1 year postoperatively., Results: Almost all outcome measures improved significantly in both groups. The percentage of sport resumption (PEMF, 79%; placebo, 80%; P = .95) and median time to sport resumption (PEMF, 17 weeks; placebo, 16 weeks; P = .69) did not differ significantly between the treatment groups. Likewise, there were no significant between-group differences with regard to the secondary functional outcomes and the computed tomography results., Conclusion: PEMF does not lead to a higher percentage of patients who resume sports or to earlier resumption of sports after arthroscopic debridement and microfracture of talar OCDs. Furthermore, no differences were found in bone repair between groups., Registration: Netherlands Trial Register NTR1636., (© 2016 The Author(s).)

Context: Isolated chondral and osteochondral defects of the knee are a difficult clinical challenge, particularly in younger patients for whom alternatives such as partial or total knee arthroplasty are rarely advised. Numerous surgical techniques have been developed to address focal cartilage defects. Cartilage treatment strategies are characterized as palliation (eg, chondroplasty and debridement), repair (eg, drilling and microfracture [MF]), or restoration (eg, autologous chondrocyte implantation [ACI], osteochondral autograft [OAT], and osteochondral allograft [OCA])., Evidence Acquisition: PubMed was searched for treatment articles using the keywords knee, articular cartilage, and osteochondral defect, with a focus on articles published in the past 5 years., Study Design: Clinical review., Level of Evidence: Level 4., Results: In general, smaller lesions (<2 cm(2)) are best treated with MF or OAT. Furthermore, OAT shows trends toward greater longevity and durability as well as improved outcomes in high-demand patients. Intermediate-size lesions (2-4 cm(2)) have shown fairly equivalent treatment results using either OAT or ACI options. For larger lesions (>4 cm(2)), ACI or OCA have shown the best results, with OCA being an option for large osteochondritis dissecans lesions and posttraumatic defects., Conclusion: These techniques may improve patient outcomes, though no single technique can reproduce normal hyaline cartilage., (© 2015 The Author(s).)

We present the novel use of particulated juvenile cartilage transfer in the upper extremity. Our patient is an active duty solider with an osteochondral defect (OCD) of the capitellum that he sustained after an improvised explosive devise injury to his left elbow.

Unlabelled: A 32-year-old male recreational athlete presented with activity-related chronic dorsal midfoot pain. Conservative treatment, including a prolonged period of immobilization, physical therapy, nonsteroidal anti-inflammatory drugs, and use of a bone stimulator, failed to resolve his symptoms. Computed tomography and magnetic resonance imaging demonstrated a cystic appearing focus within the navicular in conjunction with a osteochondral lesion within the proximal articular surface of the navicular. This case report presents an arthroscopically assisted treatment of a navicular osteochondral lesion using curettage and backfilling with fibrin glue, flowable collagen, and autogenous bone grafting., Levels of Evidence: Therapeutic, Level IV., (© 2014 The Author(s).)