The pediatric ankle can present a broad range of normal variation and pathology unique to certain stages of development. Understanding the expected age ranges of ossification and fusion about the ankle is essential to provide accurate diagnoses regarding skeletal integrity. This conclusion has been well characterized radiographically and is supported by cadaveric research. The range of appearances on magnetic resonance imaging has also been well described. Knowledge about the structure of the periosteum and perichondrium aids in image interpretation as well as explaining typical injury patterns. The expected appearance of the physis and regional bone marrow signal is also of utmost importance. Ultrasonography is a valuable tool in pediatric musculoskeletal imaging but is limited when there is concern for intra-articular pathology. Computed tomography tends to be reserved for preoperative evaluation. We describe normal variation and maturation-dependent pathology of the pediatric ankle with an emphasis on imaging considerations.

BACKGROUND:The Trabecular Metal (Zimmer Biomet, Warsaw, IN) total ankle arthroplasty (TAA) system uses a lateral approach with a fibular osteotomy to gain access to the tibiotalar joint and a sagittally curved tibial component. This is the first TAA system to laterally approach the ankle, and few studies have explored outcomes associated with this implant. This study aimed to report the 5-year clinical and radiographic outcomes as well as the survivorship of the implant.METHODS:Over a 3-year period, 2 fellowship-trained foot and ankle surgeons used this implant system to treat 38 end-stage arthritic ankles. Reoperation and revision data were collected from all patients (100%) as part of the local prospective database. Patients completed the Foot and Ankle Outcome Score (FAOS) questionnaire preoperatively and at each annual follow-up visit; scores for a minimum of 5 years were available for 28 (73.7%) patients. A radiographic analysis compared postoperative coronal and sagittal alignment in weightbearing radiographs at a minimum of 5 years with that at 3 months postoperatively, as well as cyst or lucency formation, which was available for 21 patients (55.3%).RESULTS:At 5 years, there were 3 revisions (7.9%) and 9 reoperations (23.7%). Reoperations included 4 fibular hardware removal and 5 medial gutter debridement procedures. The FAOS significantly improved for all domains (P < .05). Implant positioning did not significantly change between 3 months and 5 years postoperatively.CONCLUSION:Our 5-year results in this small series using this unique prosthesis showed good overall survivorship (92.1%) and a reoperation rate of 23.7%, along with clinically significant improvement in patient-reported outcomes.LEVELS OF EVIDENCE:Level IV: Retrospective case series.

Osteoid osteomas are benign bone tumors that are commonly found in the cortical segments of long bone but can occasionally occur in the talus of the foot. They typically present in younger males and are characterized by lesions with a vascularized nidus surrounded by sclerotic bone. Plain radiographs can often miss the diagnosis, requiring further imaging with computed tomography (CT) or magnetic resonance imaging (MRI). Lesions often lead to a significant inflammatory response resulting in an impaired range of motion and nocturnal pain. Conservative management with non-steroidal anti-inflammatory medications and a walking boot is considered first-line therapy, with failure to respond being an indication for surgical intervention. Surgical treatment traditionally consisted of en bloc resection but has been replaced by CTguided radio-frequency ablation (RFA) when conservative management has failed. Four cases of osteoid osteoma of the talus are presented which all went on to RFA after conservative management failed. The patients' non-specific symptomatology and unremarkable findings on plain radiographs led to further evaluation using MRI or CT, which aided in the diagnosis. Following imaging, RFA was performed which resulted in 100% relief of pain and symptoms in all four patients and a return to full activity without limitations. Osteoid osteomas of the talus present unique challenges due to the non-specific symptoms and complex surrounding anatomy that accompanies this condition. Management should include the use of CT for localization and RFA of the lesion, which we have shown leads to complete resolution of symptoms and return to normal daily activities.

Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: Spring ligament reconstruction (SLR) has been proposed as an adjunct to other reconstructive procedures to potentially avoid talonavicular joint fusion in progressive collapsing foot deformity (PCFD) with severe abduction deformity. However, most clinical reports present short-term follow-up data and include only a small number of patients. Recent cadaveric studies have demonstrated that the spring ligament maintains medial tibiotalar stability by forming a large confluent (tibiospring) ligament with the superficial deltoid ligament. Therefore, the purpose of this study was to investigate the medium to long-term results of our nonanatomic tibiospring ligament complex reconstruction using allograft tendon, as an adjunct to other reconstructive procedures in PCFD with severe abduction deformity. This study to our knowledge represents the largest number of patients and the longest follow-up to date. Methods: This study retrospectively reviewed prospectively collected data of 26 patients (27 feet, mean age of 61.4 years) who underwent SLR with allograft tendon as part of PCFD reconstruction. The mean follow-up of the cohort was 8 years (range, 5- 13.4). The SLR was performed when bony correction with lateral column lengthening (LCL) achieved at least 50% of abduction correction but failed to provide adequate abduction correction under intraoperative fluoroscopy. The tendon graft was positioned from the inferior navicular to the medial malleolus via bone tunnels and screw posts (Figure 1). Radiographic evaluation consisted of five parameters including talonavicular coverage angle (TNC), with the maintenance of correction being evaluated by comparing parameters from the early postoperative period (mean: 11.6 months, range, 8-17) to final follow-up. Foot and Ankle Outcome Score (FAOS) and patient satisfaction questionnaires were collected at final follow-up. Conversion to talonavicular or subtalar fusion was considered as a failure. Results: Final radiographs demonstrated successful abduction correction, with the mean TNC improving from 43.7 degrees preoperatively to 14.1 degrees postoperatively (P < .0001). All other radiographic parameters improved significantly and exhibited maintenance of the correction (Table 1). All FAOS subscales showed significant improvement. Responses to the satisfaction questionnaire were received from all except one patient, of whom 88.5% (23/26) were satisfied with the results, 96.2% (25/26) would undergo the surgery again, and 88.5% (23/26) would recommend the surgery. Eight feet (29.6%) required painful hardware removal and one (3.7%) developed non-union of the LCL osteotomy. No patient required conversion to talonavicular or subtalar fusion. Conclusion: This study demonstrates favorable medium- to long-term outcomes, as well as maintenance of the correction, following a nonanatomic tibiospring ligament complex reconstruction using allograft tendon augmentation in addition to other corrective procedures for the surgical treatment of PCFD with severe abduction deformity. As there is growing evidence of the potential for excessive foot stiffness following LCL, a remaining question is whether it is reasonable to use SLR to reduce the amount of LCL needed, as long as the bony procedure achieves at least 50% of the required abduction correction, as described in the current study.

Category: Hindfoot; Midfoot/Forefoot Introduction/ Purpose: Subluxation at the subtalar joint is one of the major radiographic features that characterize progressive collapsing foot deformity (PCFD). Although it is recognized that the cervical ligament plays an important function in maintaining the subtalar joint's stability, its role and involvement in PCFD is largely unknown. The purpose of this study was to assess the prevalence of cervical ligament insufficiency in patients with PCFD and to establish if its integrity of it changes with increasing axial plane deformity. We hypothesized that there will be a higher prevalence of cervical ligament insufficiency in a PCFD cohort compared to that of a control group. Additionally, we hypothesized that those with higher degrees of cervical ligament insufficiency will have a more severe abduction deformity and talocalcaneal subluxation. Methods: This study retrospectively reviewed magnetic resonance imaging (MRI) of 78 PCFD patients and age- and gender- matched controls. A radiologist specializing in musculoskeletal disorders evaluated the structural derangement of the cervical ligament into five grades (Grade 0 indicating normal and Grade 4 indicating a tear greater than 50% of the cross-sectional area), as previously described. To compare its involvement in PCFD, two commonly involved ligaments (spring and interosseous) in PCFD were also evaluated. Plain radiographic parameters, including the talonavicular coverage angle (TNC), lateral talo-1st metatarsal (Meary’s) angle, calcaneal pitch, and hindfoot moment arm, as well as axial plane orientation of the talus (TM-Tal) and calcaneus (TM-Calc) relative to the transmalleolar axis and talocalcaneal subluxation (Diff Calc-Tal), were correlated with the cervical ligament MRI grading system. Results: The overall distribution of the degree of cervical ligament involvement was significantly different between the PCFD and control groups (P < .001, Table 1). MRI evidence of a tear (Grades 3 or 4) in the cervical ligament was identified in 47 of 78 (60.3%) feet in the PCFD group, which was significantly higher than the control group (10.9%) and greater than that of superomedial spring (43.6%) and talocalcaneal interosseous (44.9%) ligaments. Univariate ordinal logistic regression modelling demonstrated a predictive ability of TM-Calc (Odds ratio [OR]: 1.17, 95% confidence interval [CI]: 1.06-1.30, p=.004), Diff Calc- Tal (OR: 1.15, 95% CI: 1.06-1.26, p=.002), TNC (OR: 1.08, 95% CI: 1.03-1.13, p=.003), and Meary’s angle (OR: 1.05, 95% CI: 1.02-1.10, p=.006) in determining higher cervical ligament grade on MRI (Figure 1). Conclusion: We found that cervical ligament insufficiency is a significant component of PCFD and is more common than anticipated in this study. Based on the radiographic findings in the current study, cervical ligament insufficiency appears to be primarily associated with axial plane midfoot and hindfoot deformity. If its biomechanical properties are established in the future studies, we think the reconstruction of the cervical ligament may be a potential adjunct surgical procedure for PCFD patients with significant axial plane deformity.

Mechanical ankle instability can lead to isolated cartilage lesions or early osteoarthritis. Many of the signs and symptoms can be clinically elusive with the need to isolate and define primary and secondary injuries with imaging. Currently available imaging modalities to diagnose chronic ankle instability are presented here. Level of Evidence: Diagnostic level V.

Background: Osteochondral autograft transplant (OAT) is often used to treat large osteochondral lesions of the talus and is generally associated with good outcomes. The addition of adjuncts such as cartilage extracellular matrix with bone marrow aspirate concentrate (ECM-BMAC) may further improve the OAT procedure but have not been thoroughly studied. We hypothesized that the placement of ECM-BMAC around the OAT graft would improve radiographic and patient-reported outcomes following OAT. Methods: Patients who received OAT, with ECM-BMAC or BMAC alone, were screened and their charts were reviewed. For patients who did receive ECM-BMAC, the mixture was spread around the edges of the OAT plug and into any surrounding areas of cartilage damage. Survey and radiographic data were collected. Average follow-up in both groups was over 2 years. Magnetic resonance imaging scans were scored using the Magnetic Resonance Observation of Cartilage Tissue (MOCART) system. Outcomes were compared statistically between groups. Results: Patients treated with ECM-BMAC (n = 34) demonstrated significantly greater improvement of scores in the FAOS categories Symptoms (17 vs −3; P = .02) and Sports Activities (40 vs 7; P = .02), and the MOCART category Subchondral Lamina (P = .008) compared to those treated with BMAC alone (n = 30). They also experienced significantly lower rates of postoperative cysts (53% vs 18%, P = .04) and edema (94% vs 59%, P = .02). Conclusion: The addition of ECM-BMAC to OAT was associated with improved imaging and clinical outcomes compared to OAT with BMAC alone.

Category: Midfoot/Forefoot; Lesser Toes; Other Introduction/Purpose: Bio-integrative implants, uniquely designed with high mineral fiber content, were developed to encourage paced, gradual degradation while enhancing bio-integrative response. Previous publications demonstrated the safe use of these fiber-reinforced implants in both in vivo preclinical models and in clinical use. The main focus of this study was to assess the longer-term clinical outcomes and to evaluate implant bio-integration, using a newly developed Magnetic Resonance Imaging (MRI) scoring system. The device used in this study was a Proximal Interphalangeal Joint (PIPJ) fixation implant. The scoring system implemented in this study was developed based on the review of existing literature describing MRI evaluation of degradable orthopedic implants, concentrating on various local tissue reactions and the implant-to-bone interphase characteristics. Methods: Twenty-four patients were enrolled in this multicentre study, all previously treated for a single hammertoe deformity using the fiber-reinforced, bio-integrative fixation implant. Implant material is composed of continuous reinforcing mineral fibers (SiO2, Na2O, CaO, MgO, B2O3, and P2O5), bound together by a degradable polymer [poly (L-lactide-co-D,L-lactide), PLDLA]) in a 50% w/w ratio. Final study visit took place two years post-operatively. X-ray was used to assess radiographic PIPJ fusion, defined as at least 50% bridging across the osteotomy site. MRI scans were reviewed by an independent radiologist, using a newly developed bio-integration score on a scale of 0-10. The score focused on material bio-integration defined by the evaluation of implant and bone border visibility, and parameters for local tissue response; fluid accumulation, cyst formation and local bone edema. Patient Reported Outcomes of Visual Analogue Scale (VAS) for pain, were also collected. Results were analysed and compared to previously published data. Results: Radiographic PIPJ fusion rate was 96% (n=23) at the 2-year follow-up. MRI was performed and analyzed for all patients. The border between implant and surrounding bone was scored as not visible in 88% of subjects (n=21) and partially visible in remaining 12% (n=3) (100% partially visible at the 1 -year). Mild bone edema was detected in 4% (n=1) (29% at 1-year). The edema findings were not evaluated as adverse implant-related. There were no cyst formation or fluid accumulation findings. The mean bio-integration score was 9.70+-0.69 at the 2-year timepoint (7.71+-0.46 at 1-year). Patient reported outcomes showed improvement from baseline with pain score reduced to 0.04+-0.20 compared to the initial score of 5.3+-2.5 at screening. No implant-related adverse effects were reported. Conclusion: Study results provide evidence of safe bio-integration of the fiber-reinforced implants, with favourable clinical outcome at 2-years follow-up. MRI scans did not detect fluid accumulation, cyst formation or adverse implant-related edema findings. Primarily, these study results represent a first longer-term follow-up for these implants in a clinical setting. The advanced bio-integration results at 2-years corelate well with substantial degradation previously demonstrated in animal models at a similar timepoint. Proven to provide the mechanical strength and safe elimination of the material without adverse local inflammation, this technology shows promising potential to be implemented on broader applications in orthopaedic surgery.

Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: Lateral bony impingement, one of the main causes of lateral foot pain in progressive collapsing foot deformity (PCFD), reflects disease severity and may affect surgical planning. Weightbearing computed tomography (WBCT) is known to provide better sensitivity in detecting impingement over simple radiographs, however, many Orthopaedic centers have not yet acquired WBCT imaging. This study aimed to (1) investigate the correlation of common radiographic parameters measured on standard weightbearing radiographs with talocalcaneal and calcaneofibular distance assessed with WBCT and (2) establish cut-off values for radiographic measurements on standard radiographs to detect lateral bony impingement as identified on WBCT. Methods: Ninety-one adult patients (mean age and standard deviation, 54.1 +- 17.2 years) treated for PCFD with standard preoperative radiographs and WBCT within 6 months of each other were retrospectively identified. Patients with previous ipsilateral foot and ankle surgery or asymmetric ankle arthritis (talar tilt > 2 degrees) were excluded. The talocalcaneal distance at the sinus tarsi and subfibular calcaneofibular distance were measured in multiplanar reconstructed WBCT images. Bony impingement was defined as direct contact between the structures. The relationships between WBCT measurements and four common parameters (Talonavicular coverage angle [TNC], Talo-1st metatarsal angle, Calcaneal pitch, and hindfoot moment arm [HMA]) in standard radiographs were assessed with Pearson correlations. Receiver operating characteristic (ROC) curve analysis was performed to determine the ability of radiographic parameter thresholds to predict sinus tarsi or calcaneofibular bony impingement, and the area under curve (AUC), sensitivity, specificity, negative and positive predictive value were calculated. Results: Talocalcaneal distance narrowing at the sinus tarsi on WBCT was strongly correlated with TNC (r = 0.64, p < 0.001), and the calcaneofibular distance narrowing on WBCT correlated with the HMA moderately yet best among the parameters (r=0.55, p<0.001). Interrater and intrarater reliability of WBCT measurements was excellent. TNC (AUC=0.837, 95% confidence interval [CI], 0.745-0.906) and HMA (AUC=0.959, 95%CI, 0.895-0.989) provided the best predictive ability for sinus tarsi and calcaneofibular bony impingement, respectively (Figure 1). The cut-off value for TNC for predicting sinus tarsi bony impingement was 25.4 degrees, with a sensitivity of 80.4% and a specificity of 72.5%. The cut-off value for HMA for predicting calcaneofibular bony impingement was 25.4mm, with a sensitivity of 100% and a specificity of 81.2% (Table 1). Conclusion: This study provides evidence that common radiographic parameters in standard radiographs can be potentially used to detect lateral bony impingement in PCFD. Narrowing of talocalcaneal distance at the sinus tarsi was best correlated with abduction deformity of the foot, and the narrowing of calcaneofibular distance was best correlated with valgus hindfoot deformity. TNC and HMA on standard radiographs may be used for detecting sinus tarsi and calcaneofibular bony impingement, respectively.

Creative Commons Non Commercial CC BY-NC: This article is distributed under the terms of the Creative Commons AttributionNonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage). Topical Review

BACKGROUND:A bio-integrative fiber-reinforced implant (OSSIOfiber® Hammertoe Fixation Implant, OSSIO Ltd., Caesarea, Israel) for proximal interphalangeal joint (PIPJ) correction-arthrodesis showed partial bio-integration at 1-year follow-up (1FU) in a previous study. The study was prolonged to assess the bio-integration at 2-year-follow-up (2FU).METHODS:Twenty-four patients with proximal interphalangeal joint (PIPJ) correction-arthrodesis using the fiber-reinforced implant and analysed at 1FU, completed 2FU. Follow-up included clinical examination, patient reported outcomes, radiographs, MRI and bio-integration scoring. Results were compared between the 1FU and 2FU (paired t-test).RESULTS:Radiographs confirmed fusion in 96 % (n = 23) at 2FU (1FU, 92 % (n = 22)). Implant was no longer visible in 21 % (n = 5), partially visible in 33 % (n = 8), and fully visible in 46 % (n = 11)(1FU, fully visible 100 % (n = 24)). The border between implant and surrounding bone was scored not visible in 88 % (n = 21) and partially visible in 12 % (n = 3) (1FU, border partially visible 100 % (n = 24)). There were no cyst formation or fluid accumulation findings 1FU/2FU. Mild bone edema was detected in 4 % (n = 1) (1FU, 29 % (n = 7)). None of the edema findings were considered as adverse implant related. The mean bio-integration score was 9.71 ± 0.69 at 2FU (1FU, 7.71 ± 0.46). The parameters of border between implant and bone and bone edema further improved at the 2FU compared to the 1FU, total bio-integration score was also higher at 2FU than 1FU (each p < 0.05).CONCLUSIONS:This study demonstrates 96 % PIPJ fusion rate and increased bio-integration from 1FU to 2FU, reaching advanced bio-integration of the fiber-reinforced implant at 2FU.

This first of a 2-part series of articles recounts the key points presented in a collaborative symposium sponsored jointly by the Arthritis Foundation and the American Orthopaedic Foot & Ankle Society with the intent to survey the state of scientific knowledge related to incidence, diagnosis, pathologic mechanisms, and injection treatment options for osteoarthritis (OA) of the foot and ankle. A meeting was held virtually on December 3, 2021. A group of experts were invited to present brief synopses of the current state of knowledge and research in this area. Part 1 overviews areas of epidemiology and pathophysiology, current approaches in imaging, diagnostic and therapeutic injections, and genetics. Opportunities for future research are discussed. The OA scientific community, including funding agencies, academia, industry, and regulatory agencies, must recognize the needs of patients that suffer from arthritis of foot and ankle. The foot and ankle contain a myriad of interrelated joints and tissues that together provide a critical functionality. When this functionality is compromised by OA, significant disability results, yet the foot and ankle are generally understudied by the research community. Level of Evidence: Level V - Review Article/Expert Opinion.

This second of a 2-part series of articles recounts the key points presented in a collaborative symposium sponsored jointly by the Arthritis Foundation and the American Orthopaedic Foot & Ankle Society with the intent to survey current treatment options for osteoarthritis (OA) of the foot and ankle. A meeting was held virtually on December 10, 2021. A group of experts were invited to present brief synopses of the current state of knowledge and research in this area. Topics were chosen by meeting organizers, who then identified and invited the expert speakers. Part 2 overviews the current treatment options, including orthotics, non–joint destructive procedures, as well as arthroscopies and arthroplasties in ankles and feet. Opportunities for future research are also discussed, such as developments in surgical options for ankle and the first metatarsophalangeal joint. The OA scientific community, including funding agencies, academia, industry, and regulatory agencies, must recognize the importance to patients of addressing the foot and ankle with improved basic, translational, and clinical research. Level of Evidence: Level V, review article/expert opinion.

Category: Ankle; Arthroscopy; Trauma Introduction/Purpose: The MOCART scoring system is commonly used in both the knee and ankle literature to quantitatively assess cartilage repairs on MRI. For both the knee and ankle, MOCART scores have demonstrated little ability to correlate with clinical outcomes such as survey scores. The system also suffers from issues with repeatability and reproducibility of individual scores. This study seeks to analyze the correlation between MOCART scores and PRMOIS scores obtained from the same time period from patients undergoing surgical management of an osteochondral lesion of the talus. It also seeks to determine MOCART's intra-rater reliability by analyzing multiple independent scoring attempts by the same radiologist. We hypothesized that MOCART scores would correlate with PROMIS outcomes and be repeatable for a given rater. Methods: Patients treated for an osteochondral lesion of the talus by a single surgeon in our department were screened for the existence of preoperative and postoperative MRI and survey scores completed within five months of one another. Each MRI was scored using the MOCART system by one radiologist fellowship-trained in musculoskeletal radiology on two separate occasions, with at least one week between scoring attempts. Each MOCART category and the overall score was compared to each PROMIS category. We also compared the presence of cysts and edema, as noted by the raters, to each PROMIS category. Results: MOCART scores were found to be repeatable between scoring attempts for individual categories and especially for the overall score. Preoperative MOCART scores correlated positively to preoperative PROMIS scores for the Physical Function (r= 0.0173), Pain Interference (r=0.1093), and Depression (r=0.0812) domains. Postoperative MOCART scores correlated positively with postoperative PROMIS scores for the Physical Function (r=0.1639) and Global Physical Health (r= 0.2152) domains. Postoperative MOCART scores did not correlate positively to change in PROMIS scores nor did change in MOCART scores correlate positively to change in PROMIS scores as we had expected. One significant correlation existed between postoperative MOCART score and pre to postoperative change in PROMIS Global Mental Health, but the correlation was negative (r= -0.527; p= 0.044). The presence of cyst and edema likewise did not demonstrate any consistent pattern. Conclusion: While the MOCART score may be repeatable for a given reader, it faces significant issues with correlation to PROMIS outcomes. This has been noted before for certain surgical techniques and other outcomes measurements. We find that this pattern holds true more broadly when looking at a range of methods for the treatment of osteochondral lesions. While quantitative evaluation of MRI is important for better understanding cartilage repair techniques, problems with the MOCART system should be acknowledged and solutions considered.

Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: Lateral bony impingement, one of the main causes of lateral foot pain in progressive collapsing foot deformity (PCFD), reflects disease severity and may affect surgical planning. Weightbearing computed tomography (WBCT) is known to provide better sensitivity in detecting impingement over simple radiographs, however, many Orthopaedic centers have not yet acquired WBCT imaging. This study aimed to (1) investigate the correlation of common radiographic parameters measured on standard weightbearing radiographs with talocalcaneal and calcaneofibular distance assessed with WBCT and (2) establish cut-off values for radiographic measurements on standard radiographs to detect lateral bony impingement as identified on WBCT. Methods: Ninety-one adult patients (mean age and standard deviation, 54.1 +- 17.2 years) treated for PCFD with standard preoperative radiographs and WBCT within 6 months of each other were retrospectively identified. Patients with previous ipsilateral foot and ankle surgery or asymmetric ankle arthritis (talar tilt > 2 degrees) were excluded. The talocalcaneal distance at the sinus tarsi and subfibular calcaneofibular distance were measured in multiplanar reconstructed WBCT images. Bony impingement was defined as direct contact between the structures. The relationships between WBCT measurements and four common parameters (Talonavicular coverage angle [TNC], Talo-1st metatarsal angle, Calcaneal pitch, and hindfoot moment arm [HMA]) in standard radiographs were assessed with Pearson correlations. Receiver operating characteristic (ROC) curve analysis was performed to determine the ability of radiographic parameter thresholds to predict sinus tarsi or calcaneofibular bony impingement, and the area under curve (AUC), sensitivity, specificity, negative and positive predictive value were calculated. Results: Talocalcaneal distance narrowing at the sinus tarsi on WBCT was strongly correlated with TNC (r = 0.64, p < 0.001), and the calcaneofibular distance narrowing on WBCT correlated with the HMA moderately yet best among the parameters (r=0.55, p<0.001). Interrater and intrarater reliability of WBCT measurements was excellent. TNC (AUC=0.837, 95% confidence interval [CI], 0.745-0.906) and HMA (AUC=0.959, 95%CI, 0.895-0.989) provided the best predictive ability for sinus tarsi and calcaneofibular bony impingement, respectively (Figure 1). The cut-off value for TNC for predicting sinus tarsi bony impingement was 25.4 degrees, with a sensitivity of 80.4% and a specificity of 72.5%. The cut-off value for HMA for predicting calcaneofibular bony impingement was 25.4mm, with a sensitivity of 100% and a specificity of 81.2% (Table 1). Conclusion: This study provides evidence that common radiographic parameters in standard radiographs can be potentially used to detect lateral bony impingement in PCFD. Narrowing of talocalcaneal distance at the sinus tarsi was best correlated with abduction deformity of the foot, and the narrowing of calcaneofibular distance was best correlated with valgus hindfoot deformity. TNC and HMA on standard radiographs may be used for detecting sinus tarsi and calcaneofibular bony impingement, respectively. Keywords Flatfoot AAFD Computed Tomography Weightbearing CT , Weight Bearing CT , Flatfoot

BACKGROUND:Historically, microfracture has been used to treat small talar osteochondral lesions with good results, whereas osteochondral autologous transplantation (OAT) has proven effective for the treatment of larger lesions. It is not clear which method is more effective for medium-sized lesions around the critical size of 150 mm2, above which microfracture outcomes tend to be poor. The purpose of this study was to determine the potential advantages of OAT augmented with a combination of extracellular matrix and bone marrow aspirate concentrate (ECM-BMAC) compared to debridement with ECM-BMAC (DEB) in the treatment of medium-sized osteochondral lesions of the talus (OLTs).METHODS:Clinical and radiographic data were collected retrospectively for patients treated by a single fellowship-trained foot and ankle surgeon. Magnetic resonance images (MRIs) were scored using the Magnetic Resonance Observation of Cartilage Tissue (MOCART) system and were evaluated for the presence of cysts and edema. Fifty-two patients met inclusion criteria, with 25 who received an OAT procedure. Age, body mass index, lesion size, lesion location, and follow-up time were similar between groups. Average MRI follow-up times were 16.7 months for the OAT group and 20.3 months for the DEB group (P = .38).RESULTS:Patients treated with OAT had significantly higher average total MOCART scores (69 vs 55, P = .04) and significantly lower rates of cyst (14% vs 55%, P < .01), edema (59% vs 90%, P = .04), revision surgery (0% vs 19%, P = .05), and therapeutic injection for pain (4% vs 30%, P = .02) compared to patients treated with DEB. No significant differences were detected in patient-reported outcome scores between groups.CONCLUSION:The native hyaline cartilage introduced by OAT appears to result in higher-quality repair tissue when compared to DEB, as evidenced by OAT patients' higher MOCART scores and lower rates of cyst and edema. There was no difference in clinical outcome scores, though OAT patients did not require revision surgery or therapeutic injection for pain as frequently as DEB patients.LEVEL OF EVIDENCE:Level III, retrospective comparative study.

Background: The objective of this study was to evaluate the correlation between Weightbearing CT (WBCT) markers of pronounced peritalar subluxation (PTS) and MRI findings of soft tissue insufficiency in patients with flexible Progressive Collapsing Foot Deformity (PCFD). We hypothesized that significant correlation would be found. Methods: Retrospective comparative study with 54 flexible PCFD patients. WBCT and MRI variables deformity severity were evaluated, including markers of pronounced PTS, as well as soft tissue degeneration. A multiple regression analysis and partition prediction models were used to evaluate the relationship between bone alignment and soft tissue injury. P-values of less than .05 were considered significant. Results: Degeneration of the posterior tibial tendon was significantly associated with sinus tarsi impingement (p = .04). Spring ligament degeneration correlated to subtalar joint subluxation (p = .04). Talocalcaneal interosseous ligament involvement was the only one to significantly correlate to the presence of subfibular impingement (p = .02). Conclusion: Our results demonstrated that WBCT markers of pronounced deformity and PTS were significantly correlated to MRI involvement of the PTT and other important restraints such as the spring and talocalcaneal interosseus ligaments. LEVEL OF EVIDENCE: Level III, Retrospective comparative study. (c) 2020 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Background: Microfracture (MF) has been used historically to treat osteochondral lesions of the talus (OLTs), with favorable outcomes reported in approximately 80% to 85% of cases. However, MF repairs have been shown to degrade over time at long-term follow-up, suggesting that further study into optimal OLT treatment is warranted. The use of adjuvant extracellular matrix with bone marrow aspirate concentrate (ECM-BMAC) has not been extensively evaluated in the literature. We present a comparison of patient-reported and radiographic outcomes following ECM-BMAC repair vs traditional MF. Methods: Patients who underwent MF (n = 67) or ECM-BMAC (n = 62) treatment for an OLT were identified and their charts were retrospectively reviewed. Postoperative magnetic resonance imaging (MRI) was evaluated and patient-reported outcome scores, either Foot and Ankle Outcome Scores (FAOS) or Patient-Reported Measurement Information System (PROMIS) scores, were collected. MRIs were scored by a radiologist, fellowship trained in musculoskeletal radiology, using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) system. Radiographic and clinical outcomes were compared between groups. Results: On average, patients treated with ECM-BMAC demonstrated a higher total MOCART score compared to the MF group (73 ± SD 11.5 vs 54.0 ± 24.1; P = .0015). ECM-BMAC patients also had significantly better scores for the Infill, Integration, and Signal MOCART subcategories. Last, patients treated with ECM-BMAC had a lower rate of revision compared to those treated with MF (4.8% vs 20.9%; P = .007). FAOS scores were compared between groups, with no significant differences observed. Conclusion: When comparing outcomes between patients treated for an OLT with ECM-BMAC vs traditional MF, we observed superior MRI results for ECM-BMAC patients. The rate of revision surgery was higher for MF patients, although patient-reported outcomes were similar between groups. The use of ECM-BMAC as an adjuvant therapy in the treatment of OLTs may result in improved reparative tissue when compared to MF. Level of Evidence: Level III, comparative series.

Foot and ankle instability can be seen both in acute and chronic settings, and isolating the diagnosis can be difficult. Imaging can contribute to the clinical presentation not only by identifying abnormal morphology of various supporting soft tissue structures but also by providing referring clinicians with a sense of how functionally incompetent those structures are by utilizing weight-bearing images and with comparison to the contralateral side. Loading the affected joint and visualizing changes in alignment provide clinicians with information regarding the severity of the abnormality and, therefore, how it should be managed.

Objectives: The aim of this study is to directly compare clinical outcomes following the treatment of medium-sized osteochondral lesions of the talus (OLTs) using a microfracture technique augmented with Extracellular Matrix and Bone Marrow Aspirate Concentrate (MFX) versus OAT to determine which treatment is superior for medium-sized lesions. Methods: Patients treated for an OLT between 2015 and 2018 by a single surgeon, fellowship-trained in sports medicine and foot and ankle, were screened for this study. Retrospective chart review determined treatment, lesion size, lesion location, concurrent injuries, and demographic information. Patients at a minimum of 12 months follow-up, treated with MFX or OAT, and lesions sized 80-165mm2 were eligible for inclusion. All surgical repairs were augmented with an adjuvant mixture of micronized cartilage extracellular matrix and bone marrow aspirate concentrate (ECM-BMAC). Patient-reported functional outcomes were collected through our institution’s prospective Registry database. Patients treated prior to March 2016 were administered preoperative Foot and Ankle Outcome Score questionnaires. Those treated after this date were administered preoperative Physical Function, Pain Interference, Global Physical Health, Global Mental Health, Depression, and Pain Intensity Patient-Reported Outcome Information System (PROMIS) domains. Both FAOS and PROMIS were administered postoperatively. Postoperative MRIs were assessed using a modified magnetic resonance observation of cartilage repair tissue (MOCART) score. Student’s paired and two-group t-tests were used to evaluate for statistically significant pre-to-postoperative change and differences between procedure groups (p less than 0.05). Results: Twenty-seven patients treated with MFX (age range, 14-58) and twenty-three patients treated using OAT (age range, 22-64) were identified. All OAT patients received a single-plug transplantation. The final average lesion size ± standard deviation (SD) for patients treated with MFX was 115.44mm2± 22.51 (range, 156-80mm2) and 121.78mm2± 23.98 (range, 165-80mm2) for those treated using OAT (p=0.34). On average, functional outcome scores improved pre-to-postoperatively across all scales within both groups. Statistically significant improvements were detected in PROMIS Physical Function (Δ=8.32, p=0.01), Pain Interference (Δ=-7.15, p=0.02), Global Physical Health (Δ=5.87, p=0.03), and Pain Intensity (Δ=-7.06, p=0.05) domains for the MFX cohort. For the OAT patient group, significant pre-to-postoperative change was seen in the FAOS subcategories of Pain (Δ=28.70, p=0.03), Sports Activities (Δ=43.12, p<0.01), and Quality of Life (Δ=43.75, p=0.01); overall FAOS score (Δ=29.93, p=0.01); and PROMIS Physical Function (Δ=13.66, p=0.01), Pain Interference (Δ=-14.58, p<0.01), Global Physical Health (Δ=12.2, p=0.01), Depression (Δ=-4.13, p=0.02), and Pain Intensity (Δ=-16.56, p=0.02) domains. On average, with the exception of the postoperative Sports Activities subscale, postoperative FAOS and pre-to-postoperative change in FAOS were higher and greater in the OAT patient group. Similarly, on average, the OAT group had better PROMIS t-scores indicating higher function or less pain and greater pre-to-postoperative change in each PROMIS domain. The OAT cohort’s average postoperative Pain Interference t-score (± SD) of 43.09 (± 5.81) and Depression t-score of 40.06 (± 6.84) were significantly lower than their respective counterparts in the MFX cohort: 50.08 (± 9.47) for Pain Interference and 48.09 (± 7.86) in Depression. (Table 1) Finally, the mean overall MOCART score was 55.67 (± 24.11) within the MFX cohort, average follow-up 15.29 months, and 71 (± 15.60) within the OAT cohort average follow-up 15.8 months. This difference was also statistically significant (p=0.04). Conclusion: The OAT group had a higher MOCART score indicating the use of a single osteochondral autograft plug may result in better structural repair than microfracture abrasion chondroplasty augmented with a mixture of adjuvant ECM-BMAC. In addition, higher average FAOS scores, better average PROMIS t-scores, and greater pre-to-postoperative change in the OAT patient group indicate functional results may be better in this group as well. Specifically, significantly lower Pain Interference and Depression domains and significantly higher Global Mental Health scores indicate patients treated using OAT experience less pain and better psychological benefits postoperatively compared to patients treated using MFX. These results suggest filling the lesion with transplanted autograft bone and native, hyaline cartilage may perform better than and the biomechanically inferior fibrocartilage produced following microfracture even when augmented with adjuvant therapy. OAT may result in better overall clinical outcomes, specifically in a population of patients with medium sized lesions (range, 80 mm2 -165 mm2).