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Objective Articular cartilage defect causes joint pain and finally progresses to osteoarthritis. Although the subchondral bone condition affects clinical outcomes of cartilage defects, the natural course of changes in subchondral bone and associated pain in full-thickness cartilage defects remain unknown. Therefore, we investigated the natural course of histological changes in subchondral bone and joint pain in cartilage defects using a rat model. Design Full-thickness cartilage defects were created at the medial femoral condyle of 10-week-old male Sprague-Dawley rats. Rats were sacrificed at 3, 7, 14, 28, and 56 days postoperatively, and histological including immunohistochemistry and tartrate-resistant acid phosphatase (TRAP) staining and micro-computed tomography (μCT) analyses of their knees were performed. Pain was evaluated using behavioral analysis and immunofluorescence staining of the dorsal root ganglion (DRG). Results The contour of the subchondral bone plate was maintained until day 3, but it was absorbed just under the cartilage defect from day 7 to 14. Starting on day 28, sclerotic changes surrounding the bone absorption area were detected. In the subchondral bone, the number of TRAP-positive cells peaked on day 14. Osteocalcin-positive cells were observed at 7 days, and their number gradually increased till day 56. Behavioral analysis showed that the total distance and the number of getting up by hind legs decreased on day 14. The number of calcitonin gene-related peptide-positive fibers in the DRG increased and was the highest on day 14. Conclusions The subchondral bone condition under cartilage defects dynamically changes from bone resorption to sclerosis and is related to pain level.

The cause of osteochondral lesions of the talus (OLT) in patients without a history of trauma remains unclear, and almost all nontraumatic lesions appear to involve the medial talar dome. This study aimed to investigate the relationship between foot alignment, deltoid morphology, and medial OLT in pediatric patients. In total, 28 patients (31 feet) with medial OLT (17 boys, 11 girls, mean age: 14.9 years), and 50 patients without OLT (50 feet, 31 boys, 19 girls, mean age: 14.5 years) were included in this study. The OLT patients were subdivided into traumatic and nontraumatic groups. Radiographic parameters of the foot arch were measured on weight-bearing lateral images. The extent of the OLT was measured on computed tomographic images. The ratio of deep deltoid attachment length of the talus to talar height was examined as deltoid ligament position index (DPI) on coronal magnetic resonance imaging. Nontraumatic medial lesions were frequently observed in pediatric patients (54.8%) compared to traumatic lesions. The depression of the foot arch was commonly identified in pediatric patients with resistant medial lesions. The lesion size was moderately correlated with DPI (rho = 0.48; P = 0.0086). The attachment of the deep deltoid ligament to the medial talar dome was located more proximally in nontraumatic lesions than in traumatic lesions and the control group. Our findings suggest that a combination of foot alignment and the anatomic variations in the attachment of the deep deltoid ligament contributes to the incidence of nontraumatic medial OLT in the pediatric population. Level of evidence: level IV.

Background: The bone marrow stimulation (BMS) technique is performed for osteochondral lesions of the talus (OLTs) with a lesion size of 2. The lesion defect is covered with fibrocartilage, and the clinical outcomes deteriorate over time. In contrast, the osteochondral fragment fixation can restore the native articular surface. The difference in clinical outcomes between these procedures is unclear. Purpose: To compare the clinical outcomes of BMS and osteochondral fragment fixation for OLTs and examine the characteristics of patients with poor clinical outcomes of BMS. Study Design: Cohort study; Level of evidence, 3. Methods: In total, 62 ankles in 59 patients with OLTs were included. BMS was performed for 26 ankles, and fixation was performed for 36 ankles. Clinical outcomes, including the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle Hindfoot Scale and bone marrow edema (BME) as identified on magnetic resonance imaging, were compared between the 2 groups. On computed tomography scans, the lesion location was compared with or without BME in each group. Results: The AOFAS scores in the fixation group (97.3 ± 4.3 points) were significantly higher than those in the BMS group (91.3 ± 7.7 points), even when the lesion size was 2 ( P < .05). When comparing the ankles with or without BME in each group, the AOFAS scores at the final follow-up were significantly lower for the ankles with BME (88.6 ± 7.8 points) than for those without BME (95.0 ± 6.1 points) in the BMS group ( P < .05). Lesions with BME in the sagittal plane were located more centrally than those without BME in the BMS group. In the fixation group, there were no significant differences in AOFAS scores and location of the lesion in ankles with or without BME. Conclusion: The clinical outcomes of osteochondral fragment fixation are superior to those of BMS in OLTs, even for lesions sized 2. Fixation is recommended even for small lesions, especially for more centralized lesions in the medial and lateral sides of the talus.

The subtalar joint has a possible compensatory mechanism for supramalleolar deformities; the failure of this mechanism causes the progression of ankle osteoarthritis. However, the reason for this failure has not been fully elucidated. This study aimed to evaluate the characteristics of the morphologic changes in the subtalar joint in varus ankle osteoarthritis using computed tomography. The study included 30 patients with severe osteoarthritis (modified Kellgren-Lawrence classification grade ≥ 3; mean age: 68.5 years) and 30 patients without- or with early osteoarthritis (grade 0-1; mean age: 43.0 years) as the control group. The location of cysts, osteophyte formation in the subtalar joint, and thickness of the subchondral bone plate were evaluated. In the osteoarthritis group, cyst formation was observed on the posterolateral side of the posterior facet of the calcaneus in 6 cases (20%) and of the talus in 7 cases (23.3%). Osteophyte formation was observed in the talus in 21 cases (70.0%) and in the calcaneus in 29 cases (96.6%). Osteophyte formation was observed on the posterior or lateral side of the posterior facet, and osteophyte contact between the talus and calcaneus was observed. The subchondral bone plate of the posterior medial side of the posterior facet of the talus was significantly thicker in the osteoarthritis group. The subtalar joint is less affected in severe varus ankle osteoarthritis containing a thickened subchondral bone plate in the posteromedial aspect of the posterior talar facet.

Tenosynovial giant cell tumour encompasses a group of lesions that present with synovial differentiation and most commonly occur in the joint synovium, bursae, and tendon sheaths. Diffuse-type tenosynovial giant cell tumour, previously known as pigmented villonodular synovitis, is one of the most common benign soft tissue tumours of the foot and ankle and usually affects young adults. The differential diagnosis of diffuse-type tenosynovial giant cell tumours remains a clinical problem because its clinical symptoms are similar to those of inflammatory arthritis, including rheumatoid arthritis. Moreover, persistent diffuse-type tenosynovial giant cell tumours can lead to articular deterioration, including osseous erosions and subchondral bone cysts. Joint-preserving procedures are considered optimal for treating younger patients with ankle osteoarthritis because the indication of ankle arthrodesis and total ankle arthroplasty is limited. Thus, ankle distraction arthroplasty could be an alternative for treating diffuse-type tenosynovial giant cell tumour with articular deterioration in young patients. Here, we report about a woman in her early 30s who presented with ankle pain owing to a diffuse-type tenosynovial giant cell tumour with an articular cartilage defect and subchondral bone cysts. We performed ankle distraction arthroplasty combined with an autologous bone graft. A follow-up examination at 2 years revealed preservation of physical function and pain alleviation. These findings suggest that distraction arthroplasty is a viable treatment option for remedying the destruction of the articular cartilage and subchondral bone owing to diffuse-type tenosynovial giant cell tumours in young adults.

Objectives To analyse the microstructural changes of subchondral trabecular bone in patients with osteonecrosis of the femoral head (ONFH) using multi-detector row computed tomography (MDCT). Methods We retrospectively investigated 76 hips in 50 patients diagnosed with ONFH between 2017 and 2021. Groups 1, 2, 3, and 4 comprised hips without ONFH, ONFH without femoral head collapse (FHC), ONFH with mild collapse (2 mm), respectively. All patients underwent MDCT, and the subchondral trabecular bone microstructure was assessed. Regions of interests were set at the lateral boundary of the femoral head necrotic lesion and centre of the acetabular weight-bearing portion. Results In both the femoral head and the acetabular regions, there were significant differences in Groups 2 and 3 compared to Group 1, with increased volumetric bone mineral density and apparent bone volume fraction, and more plate-like with increased connectivity, indicating that osteosclerotic changes were occurring. Conclusions In both the femoral head and the acetabular regions, osteosclerotic changes of subchondral trabecular bone microstructure were present before FHC.

Fixation of the osteochondral fragment has the advantage to restore the naturally congruent morphology of the talar dome with native hyaline cartilage in the treatment of the osteochondral lesion of the talus (OLT). Surgical treatment of medial talar osteochondral lesions is commonly done through a medial malleolar osteotomy. However, a medial malleolar osteotomy is an invasive procedure and gives negative impacts on clinical outcomes. Fixation for the posteromedial lesion of the OLT without the medial malleolar osteotomy may provide good clinical outcomes. We showed arthroscopic fixation for medial OLT without the medial malleolar osteotomy. Curettage and bone grafting between the fragment and its bed were performed, and then 2-mm bone tunnel in the medial malleolus was created. Bioabsorbable pins were inserted through the tunnel to fix the osteochondral fragment. Three cases (mean age 18.6 years) were treated using this technique for medial OLT and followed at 16 months (range, 12-24 months). The Japanese Society for Surgery of the Foot scale improved from 73.3 ± 1.2 points before surgery to 95.7 ± 7.5 points at the final follow-up. Bone union of the osteochondral fragment was confirmed on magnetic resonance imaging (MRI). Arthroscopic fixation for medial OLT is less invasive and yields good clinical outcomes. Levels of Evidence: Level V

It is unclear whether osteochondral lesions of the talus (OLTs) without chronic lateral ankle instability (CLAI) progress to osteoarthritis, which affects the therapeutic strategy. Especially, the efficacy of conservative treatment for OLT remains controversial. Since various anatomical abnormalities have been reported, there may be abnormal movement of the talus in the mortise, causing ankle instability. We hypothesized that OLTs have frequent osteoarthritic changes even without CLAI. This study aimed to evaluate the incidence of osteoarthritic changes and stress distribution on the talus in OLT.Fifty-eight ankles with medial OLT without CLAI were retrospectively reviewed. Osteophytes and joint space narrowing on radiographs were scored using Kraus's classification and compared to ankles without OLTs. OA scores were compared between over 18 years and less than 17 years in OLTs. On computed tomography images, the area of OLTs was measured. Besides, Hounsfield Units (HU) of the talus in patients with and without OLTs were measured and compared.Osteoarthritic changes were observed in 54 of the 58 ankles (94.8%) in the OLT patients. Osteophytes were frequently observed at the medial gutter and anterior tibial plafond. The OA score in patients aged over 18 years was significantly higher than that in patients aged less than 17 years (P 0.05). HU values in the talus were significantly higher than those in non-OLT patients. OLTs more than 100 mmMedial OLT without CLAI has frequently osteoarthritic changes, especially large lesions. Osteoarthritic changes in OLTs will progress over time, which needs to be considered when deciding whether to perform the surgical or non-surgical treatment.

Background: Arthroscopic anterior talofibular ligament (ATFL) repair is widely performed for chronic lateral ankle instability (CLAI). Although many studies have reported excellent outcomes with this procedure, the recurrence of instability remains a common concern. Therefore, this study aimed to analyze the risk factors for the recurrence of instability after arthroscopic repair for CLAI. Methods: Fifty-six ankles of 53 patients with a mean age of 31.8 ± 14.7 years were retrospectively reviewed. All patients underwent arthroscopic ATFL repair. If instability remained immediately after ATFL repair, calcaneofibular ligament (CFL) repair was performed. The Ankle Activity Score (AAS) was assessed preoperatively, and clinical outcomes including the Japanese Society for Surgery of the Foot scale, Karlsson-Peterson scores, and the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) were evaluated preoperatively and at the final follow-up. Talar tilt angle (TTA) was assessed preoperatively and 1 year postoperatively. Ankles were divided into 2 groups—nonrecurrence (postoperative TTA, Results: Sixteen ankles showed recurrent instability, whereas 40 did not. AAS, TTA, and social functioning in the SAFE-Q were significantly higher in the recurrence group than those in the nonrecurrence group preoperatively. In addition, the rate of poor ATFL remnant quality and the number of CFLs not repaired despite the preoperative injury diagnosis were significantly higher in the recurrence group than in the nonrecurrence group. Conclusion: Arthroscopic repair for ATFL and CFL deficiencies with preoperative high activity, poor remnant quality, and neglected CFL injury can result in the recurrence of instability. Appropriate surgical procedures to prevent the recurrence of instability should be selected for these ankles. Level of Evidence: Level IV, retrospective case series.

Background: Rotational ankle instability (RAI) is associated with the faster onset of severe ankle osteoarthritis via dysfunction of the anterior talofibular ligament, calcaneofibular ligament, and deltoid ligament. No specific clinical examination is available for RAI, and diagnostic imaging has limitations in evaluating ligament degradation. This study investigated the deltoid ligament degeneration using Hounsfield unit (HU) values on computed tomography (CT) images. Methods: Patients were enrolled in this retrospective analysis if they had undergone magnetic resonance imaging (MRI) and CT scans of the ankle. The chronic ankle instability (CAI) group comprised 20 ankles with CAI (9 men, 11 women; mean age, 28.7 years) and the control group comprised 28 ankles (16 men, 12 women, mean age, 41.3 years). The average HU values of the deep posterior tibiotalar ligament (dPTL) that constitutes the deltoid ligament were measured on coronal CT images, and MRI results were used as a reference. All patients were subdivided based on the MRI findings of dPTL injury such as fascicular disruption, irregularity, and the loss of striation. Results: A strong negative correlation was identified between age and HU values for all patients (Spearman ρ = −0.63; P < .001). The mean HU values of the dPTL for participants aged Conclusion: In addition to the conventional imaging examination such as stress radiographs and MRI, HU measurements of CT images could be useful for quantitatively and noninvasively evaluating degenerative changes in the deltoid ligament for CAI patients to assist the diagnosis of RAI. Level of Evidence: Level III. case-control study.

Ligament quality can affect clinical outcomes of ligament repair in chronic lateral ankle instability (CLAI). Magnetic resonance imaging (MRI) is used to assess the morphological changes of ligaments, but the measurement of signal intensity enables quantitative evaluation, which can evaluate the degree of the ligament quality. This study aimed to evaluate the qualitative diagnostic capacity for anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) injuries of the signal intensity on MRI.Thirty-eight and 20 ankles with and without CLAI, respectively, were included. The regions of interest (ROIs) were set in the ATFL, CFL, and tibialis anterior tendon (TAT) on MRI, and the signal intensities were measured. The signal intensities of the ATFL and CFL were corrected using TAT as the signal intensity ratio (SIR). The SIRs of the ATFL and CFL in the control and CLAI groups were compared. The relationship between the SIR of the ATFL and the arthroscopic findings was analyzed. Finally, the SIRs of the CFL in CLAI with and without CFL repair were compared.The mean SIR of the ATFL in the CLAI group (6.1 ± 2.4) was significantly higher than that in the control (2.1 ± 0.4) (P 0.01). The SIR of the ATFL was associated with the arthroscopic grading. The mean SIR of the CFL in the CLAI groups (4.1 ± 2.5) was significantly higher than that in the control (1.7 ± 0.4) (P 0.01). The SIR of the CFL in patients with the requirement of the CFL repair (6.2 ± 1.9) was significantly higher than that without the CFL repair (2.1 ± 0.5) (P 0.05).The SIR is useful for evaluating the quality of the ATFL and CFL, which enables the decision of the treatment strategy of the CLAI.

Medial malleolar osteotomy has been widely performed for posteromedial osteochondral lesions of the talus (OLT) to expose the lesion. In osteochondral fragment fixation, bioabsorbable pins should be inserted as perpendicular as possible to obtain the rigid fixation. However, the exposure of the lesion may depend on the osteotomy angle, which affects the pin insertion angles. This study aimed to analyze the relationship between pin insertion and osteotomy angles in the medial malleolar osteotomy.Twenty-four ankles of 23 patients were included. The malleolar bisector angle which was calculated from radiographs and actual osteotomy angles were measured on radiographs, and the pin insertion and osteotomy angles were measured using MRI. The intersection angle was defined by the tangential line of the tibial plafond and medial malleolar articular facet, and the bisector of this angle was defined as the malleolar bisector angle. The relationship between pin insertion and osteotomy angles was analyzed.There was no significant difference between the actual osteotomy (55.7° ± 6.6°) and malleolar bisector angles (57.4° ± 4.3°) on the radiograph. There was a significant correlation between pin insertion and osteotomy angles (rs = 0.601). The pin insertion angle (54.3° ± 5.9°) in the lower actual osteotomy angle than the malleolar bisector angle was smaller than those in the higher actual osteotomy angle (63.4° ± 8.2°).This study showed the osteotomy angle affected pin insertion angle. The osteotomy angle should not be smaller than the malleolar bisector angle at medial malleolar osteotomy to insert pins as perpendicular as possible for fixation of posteromedial OLTs.

Background Lateral ankle ligament repair for chronic lateral ankle instability is common, and arthroscopic repair of the anterior talofibular ligament (ATFL) has been widely performed. However, it is desirable to repair of calcaneofibular ligament (CFL) combined with arthroscopic ATFL repair to obtain good long term clinical outcomes. Repairing CFL through small skin incision, there is the possibility to interfere with ATFL and CFL anchors because of close attachment of ATFL and CFL at fibula. The purpose of this study is to determine the safety anchor insertion angles for ATFL and CFL on CT images and to achieve ATFL and CFL repair with minimally invasive technique. Methods Fifty ankles in 50 patients were included in this study. On a sagittal CT image, the anchor drill hole angles for ATFL and CFL were measured to avoid interference with these anchors. Then, arthroscopic ATFL repair combined with CFL repair was performed on 15 patients according to the safety insertion angles obtained by CT. CFL repair was performed through 1.5 cm length of accessory anterolateral portal. Clinical outcome was evaluated using the Japanese Society for the Surgery of the Foot (JSSF) ankle hindfoot scale and the Karlsson score before surgery and at final follow-up. Results On the CT image, the mean angles between the ATFL drill hole and anterior border of the fibula was 59.4 ± 6.5°, and those between the longitudinal axis of the fibula and ATFL drill hole, and the CFL drill hole were 34.6 ± 5.0°, and 15.1 ± 5.7°, respectively. Postoperative CT after arthroscopic ATFL repair combined with CFL repair showed that no interference with 2 anchors, and JSSF scale and the Karlsson score were significantly improved from preoperative to final follow-up. Conclusions This study showed how safety ATFL and CFL anchor insertion angles comprise a minimally invasive anatomical repair technique.

Arthroscopic ankle arthrodesis (AAA) has advantages of being less invasive and achieving a high bone union rate. However, there are still some nonunion or delayed union cases, especially those of high-grade deformity. During AAA, curettage of the subchondral bone using an abrader burr provides bone debris, and there is the possibility of bone debris being used as autograft to improve bone union. The purpose of this study is to analyze bone debris histologically, and the effect of its implantation on bone union of AAA. Bone debris from 6 patients was collected during AAA. Bone debris/atelocollagen composite was made and cultured for 4 weeks. Histological analyses were performed before and after culture. Twenty-six patients with AAA were divided into 2 groups with or without bone debris implantation, and the time to union after surgery was evaluated. In histological analysis of bone debris/atelocollagen composite, bone debris contained bone, cartilage and synovium fragment at time 0. After 4 weeks of culture, osteocalcin positive cells migrated and proliferated in the gel. Ki67 positive cells significantly increased after culture. In clinical cases, time to union was significantly shorter in the bone debris group (9.3 ± 1.3 weeks) than that in the control (12.4 ± 3.1 weeks). This study showed that bone debris contained the osteochonductive and osteoinductive properties, and there is the potential for its implantation into the ankle joint to improve bone union in ankle arthrodesis.

Background Hypermobility of the first tarsometatarsal (TMT) joint is frequently identified in patients with hallux valgus (HV); however, its association with the development of osteoarthritis in the first TMT joint in such patients remains unknown. The purpose of this study was to clarify the distribution of subchondral bone density of the first TMT joint via computed tomography (CT) using Hounsfield units (HU). Methods Patients were divided into three groups: the osteotomy (20 feet; 20 women, mean age: 61.8 years), arthrodesis (23 feet; two men, 21 women, 71.2 years), and control group (patients without HV deformity who had undergone CT scans of the foot; 13 feet; seven men, six women, 29.7 years). The HU ratios were calculated, which were defined as the HU value of each subdivision of the subarticular spongiosa of the first TMT joint [dorsomedial (DM), dorsolateral (DL), plantomedial (PM), and plantolateral (PL)] divided by the HU values of the entire joint surface. The ratios for the osteotomy, arthrodesis, and control groups were compared. The degradation of the articular cartilage in the first TMT joint was histologically graded in the arthrodesis group. Tukey–Kramer multiple comparison analysis was conducted to compare the HU ratios among the three groups, and the histological grade in each subdivision. Results The arthrodesis group demonstrated high HU ratios in the DM area of the medial cuneiform, and significantly lower HU ratios in the PL area of the first metatarsal. Lower HU ratios in the DL area were observed in both the osteotomy and the arthrodesis group when compared to that in the medial cuneiform of the control group. The histological evaluation indicated nearly normal articular cartilage for all subdivided areas in both the medial cuneiform and the first metatarsal in patients with severe HV. Conclusions Although high subchondral bone density was identified in the DM area of the medial cuneiform in severe HV, only mild degradation was histologically observed in the articular cartilage of the first TMT joint. Our findings suggest that the indications for arthrodesis of the first TMT should be reconsidered based on the severity of the degenerative changes in the first TMT joint.

Although arthroscopic anterior talofibular ligament (ATFL) repair for chronic lateral ankle instability (CLAI) has been widely performed, there are several issues such as the efficacy of the isolated ATFL repair for the ATFL and calcaneofibular ligament (CFL) injury and the influence of the poor remnant on the clinical outcomes to be discussed. This study aimed to evaluate clinical outcomes of the arthroscopic ATFL repair with the stepwise decision regarding the requirement of CFL repair and the influence of remnant qualities on clinical outcomes.Forty-four ankles underwent arthroscopic surgery to repair the lateral ankle ligament for CLAI. After arthroscopic ATFL repair, CFL repair was performed if instability remained. Clinical outcomes including the Karlsson-Peterson (KP) scores, Japanese Society for Surgery of the Foot (JSSF) scale, and the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) were assessed at the final follow-up. ATFL remnants were classified into excellent, moderate, and poor according to the arthroscopic findings, and the clinical outcomes of each remnant group were compared.Twenty-five ankles were required for CFL repair after ATFL repair. K-P score was significantly improved from 66.1 ± 5.3 to 94.8 ± 6.5 points (p 0.01). JSSF scale was significantly improved from 70.5 ± 4.5 to 95.9 ± 6.0 points (p 0.01). The SAFE-Q was also significantly improved on all subscales. There were no significant differences in clinical outcomes among excellent, moderate, and poor remnants.Stepwise decision for CFL repair in addition to arthroscopic ATFL repair gave satisfactory clinical outcomes in CLAI regardless of the remnant quality.

We aimed to evaluate the associations between implant alignment/position and patient-reported outcomes following total hip arthroplasty using CT-based simulation software.We reviewed hips of 137 patients (27 males, 110 females, mean age: 67.3 years old) who underwent total hip arthroplasty. Radiographic evaluations were based on the software for evaluation of the parameters related to implant alignment/position and femoral/3-dimensional offset using post-operative CT data. Pre-operative and one-year post-operative patient-reported outcomes using Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire scores were evaluated.The total and movement scores of normal combined anteversion and stem anteversion angle groups were significantly higher than those of lower and higher groups. The pain and movement scores of decreased femoral offset group were significantly lower than those of restored and increased femoral offset group. There were no significant differences in all scores in cup inclination and anteversion angle, stem coronal alignment, and 3-dimensional femoral offset among groups. Moreover, investigation of the associations between combined anteversion angle/stem anteversion/femoral offset and movement scores revealed that combined anteversion angle and stem anteversion were significantly associated with the movement that needs deep hip flexion and occasionally deep abduction, and high femoral offset was also associated with the movement that needs deep hip flexion.Surgeons should consider the stem anteversion, stem sagittal alignment, and combined anteversion, in addition to the femoral offset to achieve patient's post-operative satisfaction, although the surgeon may have a relatively larger choice for the implant positioning, especially on the cup side.

Recent reports have described midterm natural courses of osteochondral lesion of the talus (OLT) and lack of progression of ankle osteoarthritis (OA) in adult patients. The relationship between the OLT managed with nonoperative treatment and development of OA in children remains unknown. We report the long-term course of medial OLT in a 12-year-old female who was treated nonoperatively for 10 years. Radiographically, no osteoarthritic changes were observed at the first examination. She initially returned to her basketball club after nonoperative treatment. Although daily activities were not restricted, limitation of recreational activities began to appear at 4 years of follow-up. Subsequently, plain radiographs revealed bone absorption around the osteochondral fragment and osteophyte formation at the medial gutter, then ankle OA was advanced at the final follow-up.

The anterior talofibular ligament (ATFL) comprises the superior and inferior fascicles. The inferior fascicle is connected to the calcaneofibular ligament, and forms "lateral fibulotalocalcaneal ligament (LFTCL) complex". This study aimed to evaluate the feasibility of diagnosing LFTCL complex injuries in patients with chronic lateral ankle instability (CLAI).Forty-eight ankles (35 with CLAI and 13 without CLAI) underwent arthroscopic surgery, and preoperative magnetic resonance imaging (MRI) was conducted with 0.8 mm- thick axial and oblique slices. The diagnostic accuracy of injuries to the superior fascicle and LFTCL complex was evaluated by two observers.The sensitivity and specificity of the LFTCL complex injury were 94.7% and 92.3% for observer 1 and 84.2% and 84.6% for observer 2, respectively.MRI with 0.8 mm slices could detect LFTCL complex injury in patients with CLAI. Diagnosing the LFTCL complex injury on MRI will improve outcomes of an arthroscopic isolated ATFL repair.

Accurate evaluation of hip instability is critical for the diagnosis and successful treatment of developmental dysplasia of the hip (DDH). However, dynamic evaluation of hip instability is not well established. This study aimed to use the lateral view from a radiograph to evaluate dynamic antero-posterior hip instability in patients with DDH.Seventy-four patients (92 hips) with DDH (DDH group) and 46 patients (59 hips) without hip pain and DDH (Control group) were examined. A false profile view (FPV) according to Lequesne was taken at standard and 90° flexion with the hip of interest defined as functional FPV; the translation of the center of the femoral head (CFH) obtained from the functional FPV was measured. As a validation test, we measured the anterior translation of the CFH using ultrasonography (US).There was a significant difference between the two groups in the translation of the CFH (p 0.01). The degree of CFH translation depended on the severity of DDH (lateral center edge angle, r = -0.56, p 0.01; vertical center anterior margin angle, r = -0.57, p0.01) and lateralization of the femoral head (head lateralization index, r = 0.54, p 0.01). There was a significant correlation between functional FPV and US measurements (r = 0.71, p 0.01).The present study confirmed that antero-posterior hip instability in DDH patients can be detected using functional FPV. Our novel measurement, as a new method for assessing hip instability, may be useful for evaluating hip dynamic instability in diagnosing the etiology, and determining and evaluating the treatment for DDH at lower cost and improved accessibility.

Chronic lateral ankle instability (CLAI) is associated with osteoarthritis (OA). However, the characteristics of patients with CLAI who progress to OA are not clear. Measurement of Hounsfield Unit (HU) value on computed tomography (CT) is reported to be useful to evaluate the stress distribution. We aimed to evaluate the stress distribution in the ankle and subtalar joints and factors enhancing it in patients with CLAI. Thirty-three ankles with CLAI (CLAI group) and 26 ankles without CLAI (control group) were included. A mean age of CLAI was 35.2 years and control was 30.3 years. Color map was created in the ankle and subtalar joint according to the HU values using three-dimensional CT to identify the region with high HU values, and HU values in those regions were measured using two-dimensional CT and compared between control and CLAI groups. In CLAI group, the relationships between HU values and ankle activity score (AAS), OA, talar tilting angle (TTA), cartilage injury were assessed. The HU values in the anteromedial region of the talus and lateral region in the subtalar joint were higher than those in the control. In CLAI, patients with an AAS of ≧ 6, over 10° of TTA, cartilage injury, and OA changes in the medial gutter had significantly higher HU values in the lateral region of the subtalar joint than those with an AAS of ≦5, less than 10° of TTA without cartilage injury and OA change. CLAI patients, especially in the patients with high activity level, large TTA, cartilage injury, and OA changes at the medial gutter, have high HU values in the lateral region of the subtalar joint, which suggests that disruption of the subtalar compensation toward OA will occur. For these patients, instability should be completely eliminated to prevent ankle OA. Level III, comparative series.

Background: Fixation of osteochondral fragments is a potential option for treating an osteochondral lesion of the talus (OLT) involving large lesions in the remaining articular cartilage surface. Bioabsorbable devices, especially those made of poly-L-lactic acid (PLLA), can be used for the fixation of an OLT. Postoperative osteolysis surrounding the PLLA pins is occasionally observed; however, the significance of osteolysis remains unknown. Purpose: To elucidate the association between osteolysis surrounding the PLLA pins, histopathological findings in subchondral bone, and preoperative Hounsfield unit (HU) values at the pin fixation site. Study Design: Case Series; Level of evidence, 4. Methods: This retrospective analysis included 20 patients with OLT (11 men and 9 women; mean age, 20.9 years; 1 bilateral case). Tissue from the osteochondral fragment was collected intraoperatively using a bone biopsy needle for histological evaluation. The fragment was fixed through the biopsy hole using a PLLA pin. Osteolysis surrounding the PLLA pin was assessed at 1 year postoperatively using magnetic resonance imaging (MRI). Histopathological scores were assigned based on trabecular bone loss, empty lacunae, inflammatory granulation tissue, cartilage-like tissue, and the presence of osteoclasts. The HU values around the pin insertion site, detected on the postoperative MRI scans, were measured using the region of interest based on the preoperative coronal and sagittal computed tomography (CT) images. Results: Osteolysis was observed postoperatively in 9 ankles (42.9%). Histopathological evaluation revealed that the osteolysis group had a significantly higher pathological score than the nonosteolysis group (10.2 vs 6.3; P < .001). Lower HU values were identified in the osteolysis group on preoperative coronal and sagittal CT images ( P < .05). The histopathological score negatively correlated with preoperative HU values (Pearson r = −0.46; P = .037). Conclusion: Intraoperative biopsy of the OLT allowed for histopathological evaluation of the same site as that of the PLLA pin fixation. Our findings suggest that preoperative subchondral trabecular deterioration is associated with the incidence of postoperative osteolysis surrounding the PLLA pin. Additionally, low preoperative HU values in subchondral bone under OLT may serve as a predictor of osteolysis surrounding the PLLA pin.

Chronic ankle instability (CAI) leads to the ankle osteoarthritis (OA), and ligament repair is performed to restore ankle stability. However, anterior talofibular ligament (ATFL) repair alone is not sufficient to stabilize the ankle in some cases, which additionally require calcaneofibular ligament (CFL) repair. This study aimed to explore characteristics of CAI that necessitated the repair of both ATFL and CFL. Forty-three patients (44 ankles) with CAI treated operatively were retrospectively reviewed. After ATFL repair, patients with residual ankle instability revealed by the varus stress under fluoroscopy additionally underwent CFL repair. Preoperative condition and intraoperative findings of the combined ATFL and CFL repair (AC) (n = 24) and only ATFL repair (A) (n = 20) groups were compared. The ankle activity score of group AC was significantly higher (p.05) than that of group A. OA changes at the medial gutter were observed in 62.5% (15/24) in the group AC and 20% (4/20) in group A. Chondral/osteochondral lesions were seen in 66.7% (16/24) in the group AC and 20% (4/20) in group A. The remnant quality in group AC was inferior to that of group A. CAI that necessitated both ATFL and CFL repair exhibited characteristic findings such as high ankle activity score, high rate of chondral/osteochondral lesions and/or OA changes, and poor quality of ATFL remnants compared to those in CAI that required only ATFL repair. The repair of both ATFL and CFL should be considered in CAI which exhibit these characteristics to ensure complete correction of the instability.

Background: Chronic ankle instability (CAI) induces osteoarthritis (OA) by inflicting abnormal stresses on the medial gutter. It is important to detect early OA change and to explore factors likely to induce the OA. The purpose of this study was to evaluate subchondral bone change in the medial gutter of CAI using computed tomography (CT) scans. Methods: Thirty-five ankles with CAI (CAI group) and 35 ankles without CAI (control group) were included. The region of interest (ROI) in the subchondral bone of the medial gutter on CT axial images was set on the tibia and talus. The Hounsfield unit (HU) in ROIs was measured and corrected by the HU of the fibula in the same slice. HU ratios were compared between the CAI and control groups. In the CAI group, the relationship between the HU ratio and the talar tilt angle (TTA), OA change, and the anterior talofibular ligament (ATFL) remnant quality were analyzed. Results: The mean HU ratio in the CAI group was significantly higher than that in the control. In the CAI group, HU ratios in ≥10 degrees of TTA were significantly higher than those in Conclusion: CAI patients exhibited subchondral bone change in the medial gutter, which suggests that the elimination of instability may help to prevent or decrease the development and/or progression of osteoarthritis. Level of Evidence: Level III, comparative series.

Background: Retrograde drilling (RD) is generally used for treating osteochondral lesion of the talus (OLT) with a stable osteochondral fragment and nearly normal articular cartilage surface. Previous studies that included participants of various ages have reported good clinical results. This study aimed to clarify the clinical outcomes of RD for OLT in juvenile patients whose bone-forming ability and physical activity might affect the healing process. Methods: This retrospective study included 8 juvenile patients who underwent RD for OLT (5 boys and 3 girls, mean age 14.9 years, mean follow-up 2 years, 7 medial and 1 central lesion). American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score and ankle activity score were evaluated, and arthroscopic findings were graded according to the International Cartilage Research Society (ICRS) classification system. The condition of the underlying bone was assessed on preoperative computed tomographic images. The stability, incorporation, and subsidence of the osteochondral fragment, articular surface congruity, and the area of the bone marrow lesion (BML) were evaluated using magnetic resonance imaging (MRI). Results: AOFAS ankle-hindfoot score and ankle activity score significantly improved postoperatively. Arthroscopically, the lesions were classified as ICRS grade 0 or 1. Bone sclerosis or multiple small cysts of the underlying bone were observed in all patients. MRI demonstrated no signs of osteochondral fragment instability or subsidence, good or fair fragment incorporation, good articular surface congruity, or slight irregularity. The postoperative BML was reduced; however, these BMLs were still detectable at 1 year after surgery. Conclusion: Our data suggested that RD is an option for treating juvenile patients with OLT refractory to nonoperative treatment at short-term follow-up. Although bone sclerosis or multiple small cysts were identified in the underlying bone preoperatively and the BML under the osteochondral fragment remained postoperatively, clinical status such as pain and physical activity level were improved by RD. Level of Evidence: Level IV, retrospective case series.