Effect of a compression staple on correction of varus deformity during arthroscopic ankle arthrodesis.

BACKGROUND: Arthroscopic ankle arthrodesis (AAA) has become popular because of its higher rate of bone union, lower invasiveness, and shorter hospital stays compared to those of open arthrodesis. However, postoperative malalignment is often observed for severe varus deformity, which can cause nonunion, pain, and adjacent joint arthrosis. A compression staple can provide a persistent, strong compressive force on the bone surface. This study aimed to clarify the difference in alignment correction in AAA by comparing a compression staple and screws fixation with screws-only fixation pre- and postoperatively. METHODS: Seventy ankles in 67 patients undergoing AAA were retrospectively reviewed. AAA with three screws through the distal tibia was performed in 53 ankles, and 17 ankles underwent AAA with a compression staple and two screws. After the preparation of the joint surface arthroscopically, patients in the S group had three canulated cancellous screws inserted through the medial tibia. Patients in the CS group had a compression staple placed at the lateral aspect of the tibiotalar joint and two screws inserted through the medial side. Clinical scores and pre-and postoperative alignment on plain radiographs were compared between the two procedures. RESULTS: There were no significant differences in the pre-and postoperative Japanese Society for Surgery of the Foot scale. One ankle in the S group exhibited nonunion. There were no significant differences in talar tilt and tibiotalar angles between the groups. The tibial plafond angle in the CS group was significantly lower than that in the S group (p < 0.05). Postoperatively, talar tilt and tibiotalar angles on the coronal image, and the lateral tibiotalar angle in the CS group were significantly lower than those in the S group (p < 0.05). CONCLUSION: AAA with a compression staple and two-screw fixations could obtain more optimal alignments than AAA with screw-only fixation, even in cases with severe varus deformity.

Osteophyte Cartilage as a Potential Source for Minced Cartilage Implantation: A Novel Approach for Articular Cartilage Repair in Osteoarthritis.

Osteoarthritis (OA) is a common joint disorder characterized by cartilage degeneration, often leading to pain and functional impairment. Minced cartilage implantation (MCI) has emerged as a promising one-step alternative for large cartilage defects. However, the source of chondrocytes for MCI remains a challenge, particularly in advanced OA, as normal cartilage is scarce. We performed in vitro studies to evaluate the feasibility of MCI using osteophyte cartilage, which is present in patients with advanced OA. Osteophyte and articular cartilage samples were obtained from 22 patients who underwent total knee arthroplasty. Chondrocyte migration and proliferation were assessed using cartilage fragment/atelocollagen composites to compare the characteristics and regenerative potential of osteophytes and articular cartilage. Histological analysis revealed differences in cartilage composition between osteophytes and articular cartilage, with higher expression of type X collagen and increased chondrocyte proliferation in the osteophyte cartilage. Gene expression analysis identified distinct gene expression profiles between osteophytes and articular cartilage; the expression levels of COL2A1, ACAN, and SOX9 were not significantly different. Chondrocytes derived from osteophyte cartilage exhibit enhanced proliferation, and glycosaminoglycan production is increased in both osteophytes and articular cartilage. Osteophyte cartilage may serve as a viable alternative source of MCI for treating large cartilage defects in OA.

Relationship between pain and intra-articular pathology in patients with chronic lateral ankle instability.

PURPOSE: Repeated ankle sprains can lead to chronic lateral ankle instability (CLAI). It is unclear whether CLAI causes pain unless complicated by intra-articular lesions. This study aimed to analyze the characteristics of pain and the relationship between pain and intra-articular pathology in patients with CLAI. MATERIALS AND METHODS: Fifty-three ankles in 46 patients with CLAI who had undergone surgery were retrospectively reviewed. The self-administered foot evaluation questionnaire (SAFE-Q) was given to patients the day before surgery. Intra-articular lesions were assessed using arthroscopy and magnetic resonance imaging (MRI). In addition, the Hounsfield Unit (HU) on computed tomography (CT) of the medial gutter was measured. The relationship between pain and intra-articular findings was also analyzed. RESULTS: The pain and pain-related scores in the SAFE-Q were significantly correlated with synovitis in 96.3% (rs = - 0.532). HU ratios in the tibia and talus were also significantly correlated with pain (rs = - 0.603, - 0.534, respectively). The arthroscopic synovitis score and HU ratios in patients with high pain scores were significantly higher than those in patients with low pain scores. Forty ankles (75.5%) had synovitis and articular cartilage injuries were observed in 22 ankles (41.5%). Patients with fluid collection or bone marrow lesions (BML) scored significantly lower in pain than those without, but there was no significant difference between patients with and without cartilage injury. Multiple regression analysis revealed that a high synovitis score and HU ratio of the talus were significantly associated with high pain. CONCLUSIONS: Intra-articular lesions such as synovitis and BML were associated with pain in patients with CLAI. Osteosclerotic changes in the medial gutter also induced ankle pain, indicating that osteoarthritic changes had already begun. Therefore, lateral ankle ligament injuries after ankle sprain should be appropriately treated to avoid secondary degenerative changes.

Loosening of the anterolateral capsule affects the stability after arthroscopic lateral ankle ligament repair of chronic ankle instability.

PURPOSE: Arthroscopic anterior talofibular ligament (ATFL) repair for chronic lateral ankle instability (CLAI) has been widely performed. The recurrence of the instability after the surgery sometimes occurs, which may cause the development of osteoarthritis. Therefore, it is important to elucidate the factors of the recurrence. This study aimed to evaluate the loosening of the capsule in the MRI and whether it affected clinical outcomes or not in arthroscopic ATFL repair. MATERIALS AND METHODS: Thirty-eight ankles in 35 patients with CLAI treated by arthroscopic lateral ligament repair were included. The capsule protrusion area defined as the area that protruded ATFL laterally from the line connecting the fibula and talus attachment on MRI was measured. Capsule protrusion area in ankles with or without CLAI was compared and the relationships between it and clinical outcomes were assessed. RESULTS: The capsule protrusion area in the CLAI group (74.2 ± 36.4 mm2) was significantly larger than that in the control (25.5 ± 14.3 mm2) (p < 0.01). The capsule protrusion area in the poor remnant group (93.8 ± 36.4 mm2) was significantly larger than that in the excellent (53.2 ± 40.3 mm2) (p < 0.05). The capsule protrusion area in the patients with recurrent instability (99.8 ± 35.2 mm2) was significantly larger than that without recurrent instability (62.4 ± 30.9 mm2) (p < 0.01). Clinical scores in the recurrent group were significantly lower than those in the non-recurrent group (p < 0.05). CONCLUSIONS: Capsule loosening would be one of the causes of the recurrence of instability after arthroscopic lateral ankle ligament repair. Evaluation of the capsule protrusion area on MRI is helpful to choose appropriate surgical procedures for CLAI patients.

Comparison of Clinical Outcomes With Arthroscopic ATFL Repair With the CFL Repair and Open ATFL and CFL Repair in Chronic Lateral Ankle Instability.

It is important to eliminate instability related to chronic lateral ankle instability (CLAI) to prevent osteoarthritis progression. We performed arthroscopic anterior talofibular ligament (ATFL) repair and performed calcaneofibular ligament (CFL) repair if instability remained. This study aimed to assess the clinical outcomes of our arthroscopic procedure compared to that of open surgery. Forty ankles underwent arthroscopic surgery and 23 ankles underwent open surgery to repair the lateral ankle ligaments for CLAI. In the arthroscopic surgery, varus stress was applied under fluoroscopy after ATFL repair, and CFL repair was performed if instability remained. Open surgery was performed using the Broström procedure with ATFL and CFL repair. To assess clinical outcomes, American Orthopaedic Foot & Ankle Society (AOFAS) and Karlsson-Peterson (KP) scores were collected preoperatively and at the final follow-up. The talar tilt angle (TTA) was measured preoperatively and 1 year postoperatively. The arthroscopic group showed significantly higher AOFAS and KP scores at the final follow-up compared to the open surgery group. There was no significant difference in TTA at 1 year between the groups. In open surgery, 2 patients required revision surgery. There were no major complications, but scar-related pain in 2 cases of open surgery was reported. Arthroscopic ATFL repair with the CFL repair gave satisfactory clinical outcomes compared to open surgery in CLAI because of low invasive to soft tissue including the joint capsule. It is important to minimize soft tissue dissection in repairing the lateral ankle ligament in patients with CLAI.

The role of substance P on maintaining ligament homeostasis by inhibiting endochondral ossification during osteoarthritis progression.

PURPOSE: Osteoarthritis (OA) is characterized by the degeneration of various tissues, including ligaments. However, pathological changes such as chondrogenesis and ossification in ligaments during OA are still unclear. Substance P (SP), a neuropeptide, has various functions including bone metabolism. This study aimed to analyze the expression and function of SP in OA ligaments, and the therapeutic potential of SP agonists in OA mice. MATERIALS AND METHODS: Expressions of SP, SOX9, and MMP13 were histologically analyzed in the posterior cruciate ligament (PCL) in humans with OA and Senescence-accelerated mouse-prone 8 (SAMP8) mice as a spontaneous OA model. The effect of SP agonists on chondrogenesis was evaluated using human ligament cells. Finally, SP agonists were administered intraperitoneally to destabilized medial meniscus (DMM) mice, and the PCL was histologically evaluated. RESULTS: In PCL of humans and mice, the expression of SP, SOX9, and MMP13 was upregulated as OA progressed, but their expression was downregulated in severe degeneration. SP and SOX9 were co-expressed in chondrocyte-like cells. In ligament cells, SP agonists downregulated SOX9, RUNX2, and COL10A1. On evaluating chondrogenesis in ligament cells, pellet diameter was reduced in those treated with the SP agonists compared to those untreated. Administration of SP agonists ameliorated PCL degeneration in DMM mice. The Osteoarthritis Research Society and ligament scores in mice with SP agonists were significantly lower than those without SP agonists. CONCLUSIONS: SP plays an important role in maintaining ligament homeostasis by inhibiting endochondral ossification during OA progression. Targeting SP has therapeutic potential for preventing ligament degeneration.

Stepwise decision making for CFL repair in addition to arthroscopic ATFL repair yields good clinical outcomes in chronic lateral ankle instability regardless of the remnant quality.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: Stepwise decision for CFL repair in addition to arthroscopic ATFL repair gave satisfactory clinical outcomes in CLAI regardless of the remnant quality.

Correction effects of peroneus longus contraction on hallux valgus radiographic parameters.

BACKGROUND: Hypermobility of the first tarsometatarsal joint plays an important role in hallux valgus pathogenesis. The peroneus longus is recognized as a dynamic stabilizer of the first tarsometatarsal joint. However, the association between the peroneus longus function and the hallux valgus deformity remains unknown. This study aimed to determine the effect of peroneus longus contraction induced by electrical muscle stimulation on the correction of hallux valgus radiographic parameters in patients with hallux valgus. METHODS: Thirty-five patients with hallux valgus (47 feet; 2 men, 33 women; mean age 64.9 years) were included. Non-weight-bearing dorsoplantar radiographs of the foot were obtained with and without electrical muscle stimulation of the peroneus longus. Radiographic parameters of hallux valgus deformities, including the hallux valgus angle, intermetatarsal angle, first metatarsal protrusion distance, and distance between the first and second metatarsal bases, were measured and compared between the two conditions. RESULTS: All hallux valgus radiographic parameters were significantly improved by contraction of the peroneus longus. The median hallux valgus angle decreased by 13.2°. Fewer changes in the hallux valgus angle were identified in patients with severe deformity and geriatric patients. CONCLUSIONS: Although the peroneus longus muscle has received little attention in the management of hallux valgus, our findings suggest that it has the potential to be a novel conservative approach for treating mild-to-moderate hallux valgus.

MRI signal intensity ratio reflects the quality of the anterior talofibular and calcaneofibular ligaments in patients with chronic lateral ankle instability.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: The SIR is useful for evaluating the quality of the ATFL and CFL, which enables the decision of the treatment strategy of the CLAI.

Hounsfield Unit values on the subchondral bone are related to clinical outcomes in bone marrow stimulation for osteochondral lesions of the talus.

BACKGROUND: Poor clinical outcomes in bone marrow stimulation (BMS) for the osteochondral lesion of the talus (OLT) are caused by subchondral bone deterioration. It is reported that microfracture induces endochondral ossification in the subchondral bone, which may affect the subchondral bone condition after BMS. This study analyzed osteosclerotic patterns of the bed in OLTs on computed tomography (CT) images and the relationship between the subchondral bone condition and clinical outcomes of BMS. METHODS: Sixty-nine ankles in 61 patients with OLT were included. Hounsfield unit (HU) on the bed of OLTs was measured on CT images and the pattern of osteosclerosis or absorption in the bed was analyzed. In these patients, 25 ankles in 24 patients underwent BMS. They were divided into 2 groups according to the presence of bone marrow edema (BME) one year after surgery, and clinical outcomes were compared. RESULTS: HUs in the anterior region were significantly higher than those of other areas. In patients with BMS, the JSSF scale for BME positive group (88.0 ± 7.7 points) was significantly lower than that for BME negative group (95.0 ± 6.1 points) (p < 0.05) at the final follow-up. On preoperative CT images, HU values of the central region in the BME-positive group were significantly lower than those in the BME-negative group (p < 0.05). CONCLUSION: Osteosclerotic changes in the anterior part of the bed were frequently observed, and BMS for the area with low HU values decreased clinical outcomes. BMS should be performed with attention to subchondral bone condition to obtain good clinical outcomes. LEVEL OF EVIDENCE: 4, case series.

Development of osteophytes and joint space narrowing is associated with cartilage degeneration of the osteochondral fragment in the osteochondral lesion of the talus.

BACKGROUND: During surgery for osteochondral lesions of the talus (OLT), preservation or excision of the osteochondral fragment is chosen based on the cartilage condition which influences the indication and clinical outcomes of surgical treatments. However, it is difficult to predict arthroscopic and histological findings of the cartilage on osteochondral fragments by radiographic evaluation. We focused on osteoarthritis (OA) changes on plain radiographs to predict the cartilage condition of the OLT. This study aimed to evaluate whether OA changes, including osteophyte and joint space narrowing, could predict arthroscopic and histological findings of the cartilage in OLT. METHODS: Seventy ankles with OLT were included in this study. Osteophytes and joint space narrowing were scored on plain radiographs. Lesion sizes were measured on computed tomography images. The cartilage surfaces of fragments were arthroscopically assessed using the International Cartilage Repair Society (ICRS) grade. Biopsy specimens from 32 ankles were histologically analyzed using the Mankin score. The relationships between OA scores, lesion size, ICRS grades, and Mankin score were analyzed. RESULTS: OA changes were frequently observed with increasing ICRS grades, especially in the medial tibiotalar joint. OA scores in patients with ICRS grade 1 were significantly lower than those in ICRS grades 2,3, and 4. The lesion sizes in patients with ICRS grade 3 and 4 were significantly smaller than those in patients with ICRS grade 1 and 2. Histological analysis showed increasing Mankin scores as the ICRS grade worsened. A mild correlation existed between the OA and Mankin scores (rs = 0.494). CONCLUSIONS: OA changes, such as osteophyte formation and joint space narrowing, are associated with arthroscopic findings of the articular surface and cartilage degeneration in osteochondral fragment in OLT. Articular cartilage conditions can be predicted by OA changes on plain radiographs, which is useful for choosing the appropriate treatment for patients with OLT. LEVEL OF EVIDENCE: Level Ⅳ, case series.

The role of the oblique medial osteotomy angle during osteochondral fragment fixation in patients with a posteromedial osteochondral lesion of the talus.

BACKGROUND: 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. METHODS: 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. RESULTS: 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°). CONCLUSIONS: 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.

Augmentation of the medial collateral ligament using suture tape reduces the recurrence after corrective surgery for severe hallux valgus.

BACKGROUND: The severity of hallux valgus (HV) deformity is associated with recurrence after corrective surgery because of the degenerative change of the medial capsule including the medial collateral ligament (MCL) at the metatarsophalangeal joint. This study aimed to assess the effectiveness of the MCL augmentation using a suture tape anchor of the recurrence of HV and to evaluate the histological changes of the medial joint capsule in HV patients. METHODS: Thirty-four feet with severe hallux valgus were included and divided into 2 groups. Seventeen feet had the MCL reconstruction using suture tape anchor with a combination of the corrective osteotomy as the suture tape group (mean age, 64.0 years), and other seventeen feet had the corrective osteotomy without MCL reconstruction as the control group (mean age, 62.0 years). HV angle (HVA) and intermetatarsal angle (IMA) on the weight-bearing radiograms and the Japanese Society for Surgery of the Foot (JSSF) score in both groups were compared at the final follow-up. The medial capsule was harvested from other 20 feet with HV and the relationship between the severity of HV and the histological findings was analyzed. RESULTS: HVA, IMA, and JSSF scores in both groups were significantly improved from preoperatively to the final follow-up (P < 0.01). At the final follow-up, HVA in the suture tape group (9.2°) was significantly smaller than that in the control (15.4°) (P < 0.01). There were no significant differences in the IMA and the JSSF score at the final follow-up between both groups. Histological scores in HV with ≥40° HVA was significantly worse than those in <40°. CONCLUSION: The medial joint capsule in severe HV deformity showed the degenerative change and the MCL reconstruction using suture tape combined with osteotomy provides a strong medial constraint to prevent the recurrence of the deformity in severe hallux valgus. LEVEL OF CLINICAL EVIDENCE: 3.

Morphology and deformity of the distal phalanx in hallux valgus.

BACKGROUND: Studies have shown that the first metatarsal contributes to hallux valgus. The proximal phalanx, another factor that defines the hallux valgus angle, also contributes to the development of hallux valgus. There have been no reports on the use of computed tomography to evaluate bone morphology of the proximal phalanx. The purpose of this study was to analyze the morphology and deformity of the proximal phalanx and its relationship to hallux valgus using computed tomography, and to consider the indications for proximal phalanx surgery in hallux valgus. METHODS: Patients who consulted at our clinic for foot and ankle disorders and underwent both weight-bearing radiography and computed tomography between May 2019 and March 2022 were included in the study. The hallux valgus angle, sesamoid subluxation, first metatarsal length, proximal phalanx length, metatarsal-proximal phalanx ratio, proximal phalanx valgus angle, metatarsal-proximal phalanx angle, proximal phalanx rotation angle, and distal phalanx-proximal phalanx angle were measured. These parameters were compared between the hallux valgus and control groups. In the hallux valgus group, the hallux valgus and proximal phalanx valgus angles were measured and compared using weight-bearing radiographs. RESULTS: A total of 83 feet in 65 patients were diagnosed with hallux valgus (hallux valgus group; mean age of 68.0 ± 13.8 years) and 30 feet in 22 patients without hallux valgus (control group; mean age of 67.0 ± 25.8 years) were included in the study. The proximal phalanx length, metatarsal-proximal phalanx ratio and angle, and distal phalanx-proximal phalanx angle were significantly greater in the hallux valgus group than in the control group. However, the proximal phalanx valgus and rotation angles were not significantly different between the groups. CONCLUSION: Since there was no significant difference in the proximal phalanx morphology, except length, between the hallux valgus and control groups, the indications for osteotomy of the proximal phalanx should be carefully considered.

Quantitative evaluation of calcaneofibular ligament injury on the oblique coronal view of magnetic resonance imaging in chronic lateral ankle instability.

BACKGROUND: In the treatment of chronic lateral ankle instability (CLAI), the repair of the calcaneofibular ligament (CFL) and anterior talofibular ligament (ATFL) is still being discussed, possibly due to the difficulty in assessing CFL injuries. In particular, it is challenging to evaluate the extent of CFL deficiency quantitively. We hypothesized that CFL tension change would alter morphology of the CFL on magnetic resonance imaging (MRI) and that measuring this morphological change allows assessing CFL injury quantitatively. Thus, this study aimed to analyze the feasibility of quantitatively assessing CFL injuries using MRI. METHODS: Sixty-four ankles with CLAI were included and divided into two groups: with (ATFL and CFL group, 31 ankles) or without CFL repair (ATFL group, 33 ankles) in addition to arthroscopic ATFL repair. The angle between the CFL and calcaneal axis (CFLCA) and the bending angles of the CFL was defined as the flexed CFL angle (FCA) were measured on the oblique CFL view of preoperative MRI. The diagnostic abilities of these angles for CFL injury and correlations between these angles and stress radiographs were analyzed. RESULTS: The sensitivity and specificity of CFLCA were 86.7 % and 88.7 %, and those of FCA were 63.3 % and 77.4 %, respectively. The combination of CFLCA and FCA improved the sensitivity to 93.3 %. The cutoff points of CFLCA and FCA were 3.8° and 121.2°, respectively. There were significant moderate and weak correlations between the talar tilting angle and CFLCA or FCA (rs = -0.533, and rs = -0.402, respectively). The CFLCA and FCA were significantly smaller in the ATFL and CFL group than those in the other groups. CONCLUSIONS: Measurement of CFLCA and FCA in oblique CFL view on MRI could be useful for the quantitative evaluation of CFL injury in patients with CLAI． LEVEL OF EVIDENCE: Level IV. case-control study.

High-fat diet-induced obesity accelerates the progression of spontaneous osteoarthritis in Senescence-Accelerated Mouse Prone 8 (SAMP8).

OBJECTIVES: Aging and obesity are major risk factors for osteoarthritis (OA), a widespread disease currently lacking efficient treatments. Senescence-accelerated mouse prone 8 (SAMP8) display early-onset aging phenotypes, including OA. This study investigates the impacts of high-fat diet (HFD)-induced obesity on OA development in SAMP8. METHODS: SAMP8 at five weeks were fed either a normal chow diet or an HFD for ten weeks to induce obesity. Parameters related to obesity, liver function, and lipid and glucose metabolism were analyzed. At 14 weeks of age, knee joint pathology, bone mineral density, and muscle strength were assessed. Immunohistochemistry and TUNEL staining were performed to evaluate markers for cartilage degeneration and chondrocyte apoptosis. RESULTS: At 14 weeks of age, HFD-induced obesity increased liver and adipose tissue inflammation in SAMP8 without further exacerbating diabetes. Histological scoring revealed aggravated cartilage, menisci deterioration, and synovitis, while no further loss of bone mineral density or muscle strength was observed. Increased chondrocyte apoptosis was detected in knee joints following HFD feeding. CONCLUSIONS: Ten weeks of HFD feeding promotes spontaneous OA progression in 14-week-old SAMP8, potentially via liver damage subsequent chondrocyte apoptosis. This aging-obese mouse model may prove valuable for further exploration of spontaneous OA pathophysiology.

Distributional patterns of subchondral bone density and histopathological features of the first tarsometatarsal joint in hallux valgus feet.

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.

High incidence of osteoarthritic changes in patients with osteochondral lesions of the talus without chronic lateral ankle instability.

BACKGROUND: 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. METHODS: 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. RESULTS: 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 mm2 had a significantly higher osteoarthritic score than those less than 100 mm2. CONCLUSION: Medial 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.

High-stress distribution in the lateral region of the subtalar joint in the patient with chronic lateral ankle instability.

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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 OF EVIDENCE: Level III, comparative series.

Characteristics of Chronic Ankle Instability Requiring Both Anterior Talofibular and Calcaneofibular Ligament Repair.

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.