Bone Mineralization Changes in the Subchondral Bone of the Medial Gutter in Chronic Lateral Ankle Instability

Clinical significance of posterior talofibular ligament injury in chronic lateral ankle instability

PURPOSE

Although arthroscopic repair of the anterior talofibular ligament (ATFL) is widely performed, the effect of posterior talofibular ligament (PTFL) injury on clinical outcomes remains unclear. This study aimed to evaluate the magnetic resonance imaging (MRI) findings of the PTFL in chronic lateral ankle instability (CLAI) and determine whether the presence or absence of PTFL injury affected the postoperative outcomes of arthroscopic ATFL repair.

MATERIALS AND METHODS

Forty ankles of 35 patients who underwent arthroscopic repair for CLAI were included in this study as the experimental group, together with 25 ankles of 24 patients without CLAI as the control group. The PTFL thickness (PTFLT) and PTFL cross-sectional area (PTFLCSA) were measured using MRI and compared between the control and CLAI groups. The clinical outcomes of arthroscopic repair were compared between ankles with and without PTFL injuries.

RESULTS

The mean PTFLT and PTFLCSA values were significantly higher in the CLAI group than in the control group. The PTFLT and PTFLCSA in the PTFL injury group were significantly larger than those in the non-injury group in the CLAI group. Postoperatively, there were no significant differences in clinical scores and talar tilt angles on stress radiographs between ankles with and without PTFL injury; however, instability recurrence was frequently observed in ankles with PTFL injury (32.1%) compared to the ankles without PTFL injury (16.7%). Poor-quality ATFL remnant, ATFL inferior fascicle, and calcaneofibular ligament injuries were frequently observed in ankles with PTFL injuries.

CONCLUSIONS

Our findings indicate that PTFL injury is highly associated with CLAI but it does not affect postoperative clinical scores. However, postoperative instability recurrence was more often observed in ankles with PTFL injuries, given that they frequently have poor-quality ATFL remnants and CFL injuries.

EVIDENCE LEVEL

Level III.

The Hounsfield Unit Values of Talar Subchondral Bone Predict Articular Cartilage Degeneration in Patients With Ankle Osteoarthritis

BACKGROUND

Therapeutic strategies for ankle osteoarthritis (OA) are determined based on OA staging, alignment, and articular cartilage conditions. However, it is difficult to evaluate the degeneration of the remaining cartilage using imaging modalities. Subchondral bone plays a crucial role in maintaining cartilage homeostasis. Measurement of local Hounsfield unit (HU) values allows for the quantitative assessment of small changes in the subchondral bone. This study aimed to evaluate a relationship between the HU values of the subchondral bone and the histologic findings of articular cartilage in ankle OA.

METHODS

The talar articular surface was harvested from 14 ankles during arthroplasty. The talus was divided into anterior, middle, and posterior parts, and histologic specimens were prepared. Safranin O staining was performed and histologic findings were evaluated using the modified Mankin score. The regions of interest (ROIs) were set in the medial, central, and lateral regions of the specimens and computed tomography (CT) images, and the relationship between the HU values and histologic findings was analyzed.

RESULTS

As OA progressed, cartilage defects increased. In conjunction with cartilage degeneration, the subchondral bone plate thickened, and the HU values increased. The HU value significantly and positively correlated with the modified Mankin score (r = 0.756), subchondral bone thickness (r = 0.674, P < .01), and trabecular bone area (r = 0.637). The cutoff HU values were 594 (sensitivity, 0.813; specificity, 0.944) for 3 points and 727 (sensitivity, 0.929; specificity, 0.782) for 11 points on the modified Mankin score.

CONCLUSION

Significant correlations between HU values and cartilage degeneration in ankle OA were noted. Measuring HU values on CT images can be useful for evaluating the joint surface condition, including histologic findings of the remaining cartilage.

The Relationship Between Calcaneofibular Ligament Injury and Ankle Osteoarthritis Progression: A Comprehensive Analysis of Stress Distribution and Osteophyte Formation in the Subtalar Joint

BACKGROUND

Ankle osteoarthritis (OA) mainly arises from trauma, particularly lateral ligament injuries. Among lateral ligament injuries, ankles with calcaneofibular ligament (CFL) injuries exhibit increased instability and can be a risk factor ankle OA progression. However, the relationship between CFL injury and OA progression remains unclear. Therefore, this study aims to assess the relationship between CFL injuries and ankle OA by investigating stress changes and osteophyte formation in subtalar joint.

METHODS

We retrospectively reviewed the magnetic resonance imaging (MRI) and plain radiographic evaluations of 100 ankles of 91 patients presenting with chronic ankle instability (CAI), ankle OA, or other ankle conditions. The association between CFL injuries on the oblique view of MRI and the severity of ankle OA (based on Takakura-Tanaka classification) was statistically evaluated. Additionally, 71 ankles were further subjected to CT evaluation to determine the association between the CFL injuries and the Hounsfield unit (HU) ratios of the subtalar joint and medial gutter, and the correlation between the subtalar HU ratios and osteophyte severity were statistically evaluated.

RESULTS

CFL injury was observed in 35.9% (14/39) of patients with stage 0, 42.9% (9/21) with stage 1, 50.0% (10/20) with stage 2, 100% (9/9) with stage 3a, and 90.9% (10/11) with stage 3b. CFL-injured ankles exhibited higher HU ratios in the medial gutter and lower ratios in the medial posterior subtalar joint compared to uninjured ankles. A negative correlation was observed between medial osteophyte severity and the medial subtalar joint HU ratio.

CONCLUSION

Our findings suggest that CFL injuries are common in severe ankle OA impairing the compensatory function of the subtalar joint through abnormal stress distribution and osteophyte formation.

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.

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.

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.

LEVEL OF EVIDENCE: 4

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.

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.

LEVEL OF EVIDENCE: 4

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.

Using Radiomics to Detect Subtle Architecture Changes of Cartilage and Subchondral Bone in Chronic Lateral Ankle Instability Patients Based on MRI PD-FS Images

RATIONALE AND OBJECTIVES

To use radiomics to detect the subtle changes of cartilage and subchondral bone in chronic lateral ankle instability (CLAI) patients based on MRI PD-FS images.

MATERIALS AND METHODS

A total of 215 CLAI patients and 186 healthy controls were included and randomly split into a training set (n=281, patients/controls=151/130) and an independent test set (n=120, patients/controls=64/56). They underwent ankle MRI examinations. On sagittal PD-FS images, eight cartilage regions and their corresponding subchondral bone regions were drawn. Radiomics models of cartilage, subchondral bone and combined cartilage and subchondral bone were built to differentiate CLAI patients from controls. A receiver operating characteristic curve (ROC) was used to assess the model's performance.

RESULTS

In the test dataset, the cartilage model yielded an area under the curve (AUC) of 0.0.912 (95% confidence interval (CI): 0.858-0.965, p<0.001), a sensitivity of 0.859, a specificity of 0.893, a negative predictive value (NPV) of 0.848, and a positive predictive value (PPV) of 0.902. The subchondral bone model yielded an AUC of 0.837 (95% CI: 0.766-0.907, p<0.001), a sensitivity of 0.875, a specificity of 0.714, an NPV of 0.833, and a PPV of 0.778. For the combined model, the AUC was 0.921 (95% CI: 0.863-0.972, p<0.001), sensitivity was 0.844, specificity was 0.911, NPV was 0.836, and PPV was 0.915, whose AUC was higher than those of both the cartilage model and the subchondral bone model.

CONCLUSION

The combined radiomics model achieved satisfying performance in detecting potential early architectural changes in cartilage and subchondral bone for CLAI patients.

Risk Factors for the Recurrence of Instability After Lateral Ankle Ligament Repair

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, <6 degrees) and recurrence (postoperative TTA, ≥6 degrees)-and clinical outcomes were compared.

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.

Pure ligamentous ankle dislocation: A case report

INTRODUCTION AND IMPORTANCE

Pure ankle dislocation is a rare injury, and this injury is an orthopedic emergency requiring immediate reduction. In more common circumstances, this injury is usually associated with malleolar fractures. The standardized treatment protocol is still deficient.

CASE PRESENTATION

We report a case of a 33-year-old woman who presented with an open ankle dislocation without concomitant malleolar fractures. Early extensive wound debridement, immediate reduction, and immobilization of the ankle joint using an external fixator were performed during the first surgery. During the second surgery, which was performed 3 weeks later, the medial and lateral ankle ligaments were repaired, and a suture tape internal brace was added. A good functional outcome with the American Foot and Ankle Society score of 87 was achieved at 1-year follow-up.

DISCUSSION

In an open dislocation with massive ligamentous injury, staged surgery could be performed to prevent deep infection, with extensive debridement and immobilization using an external fixator in the first stage and ligament repair in the second stage. An internal brace using a suture tape is an option for ligament repair if the remnant is not sufficient to be repaired, as in this case. Early range of motion exercises should be initiated after second-stage surgery to prevent stiffness.

CONCLUSION

Staged surgery using an external fixator and ligament repair using a suture tape and internal brace augmentation can be an effective option for a pure ligamentous ankle dislocation with an open wound and a poor remnant of ankle ligaments.

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.

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.

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.

Joint Stabilization Surgery for Chronic Ankle Instability and Medial Ankle Osteoarthritis: A Critically Appraised Topic

Clinical Scenario: Patients with chronic ankle instability (CAI) who require surgical intervention are often diagnosed with medial ankle osteoarthritis (OA). Lateral joint stabilization procedures are commonly performed among this patient population to restore bony alignment and improve cartilage loading patterns to increase patient-reported function and mitigate further degenerative changes. Focused Clinical Question: What is the available evidence to support joint stabilization procedures on patient-reported outcomes and progression of radiographic OA among patients with CAI who have medial ankle OA? Summary of Key Findings: An electronic search of relevant databases was performed to identify peer-reviewed articles examining preoperative and postoperative clinical outcomes and radiographic evidence of ankle OA. A total of 3 peer-reviewed articles were retrieved. All 3 articles employed a retrospective case series study design. All 3 articles demonstrated improved patient-reported outcomes at the final follow-up visit. Two articles demonstrated that between 11% and 27% of patients progressed in at least 1stage of radiographic ankle OA between the preoperative assessment and the final follow-up visit (40-56 mo). Clinical Bottom Line: Joint stabilization surgery for patients with CAI and medial ankle OA is associated with improved clinical outcomes and a low rate of worsening radiographic joint degeneration within the first 5 years. Strength of Recommendation: Consistent evidence exists across all 3 articles. However, this evidence is based on a low-quality study design. Therefore, there is a grade-C level of evidence to support joint stabilization for improving patient-reported and radiographic outcomes within the first 5 years after surgery for patients with CAI and medial ankle OA.

Quantitative Analysis of Deltoid Ligament Degradation in Patients With Chronic Ankle Instability Using Computed Tomographic Images

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 <60 years were 81.0 HU for the control group (21 ankles) and 69.5 HU for the CAI group (P = .0075). No significant differences in the HU values were observed for the dPTL among the MRI subgroups.

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.