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.

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.

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 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.

Effects of Preoperative Abnormality of Posterior Tibial Tendon on the Surgical Outcomes of Medial Osteochondral Lesion of the Talus.

BACKGROUND: Although surgical treatment for osteochondral lesion of the talus (OLT) can obtain good clinical outcomes, the rate of return to sports is variable. It is reported that medial OLT unrelated to trauma has abnormal structures in the medial aspect, which may induce the medial OLT due to the medial instability. The posterior tibial tendon (PTT) plays an important role in the stabilization of the foot, and high mechanical stress may be added to the PTT to compensate for medial instability in medial OLT. We investigated whether abnormal PTT findings on preoperative magnetic resonance imaging (MRI) in patients with OLT affect clinical outcomes after surgery.  Methods: Eighty-one ankles in 74 patients who were treated surgically for OLT were included in this study (41 men and 33 women; mean age, 26.0 years). Abnormalities of the PTT were evaluated using preoperative MRI. The Japanese Society for Surgery of the Foot (JSSF) scale, arch height, and ankle activity score (AAS) on standing plain radiogram were compared between patients with and those without preoperative PTT abnormalities. RESULTS: Twenty-five ankles (30.9%) had PTT abnormalities on preoperative MRI. All patients with preoperative PTT abnormalities were medial OLT. There were no significant differences in the preoperative JSSF scale in the procedures for OLT. The postoperative JSSF scale and arch height were significantly lower in patients with preoperative PTT abnormalities than those without them. AAS in patients with preoperative abnormalities significantly decreased at the final follow-up.  Conclusion: PTT abnormalities on preoperative MRI may affect clinical outcomes even in preoperative asymptomatic patients in the medial OLT unrelated to trauma.

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.

Safe Insertion Angle of the Suture Button to Avoid Saphenous Structure in Syndesmosis Injury.

In placing the medial suture button for syndesmosis injury, the risk of great saphenous vein and saphenous nerve injury has been reported. This study aimed to determine the safe insertion angle of the guide pin to avoid saphenous structure injury during suture button fixation. The incidence of saphenous structure injury was investigated using 8 legs of cadavers. The greater saphenous vein was depicted on the skin using near-infrared light (VeinViewer® Flex) and the distance between the greater saphenous vein and the posterior edge of the tibia at levels of 10, 20, and 30 mm from the joint line of the tibiotalar joint was measured in the 60 legs of healthy participants. On computed tomography (CT) images, the angles between the greater saphenous vein and transmalleolar axis at levels of 10, 20, and 30 mm from the joint line of the tibiotalar joint were measured. The cadaveric study revealed that the percentages of contact with the saphenous nerve were 8.3% to 16.7%. Using near-infrared light, the vein and tibia distance was 32.9 ± 6.8 mm of 10 mm, 26.6 ± 6.4 mm of 20 mm, and 20.4 ± 6.4 mm of 30 mm. The angle between the vein and transmalleolar axis was 1.0° to 9.4°, and more proximal, the angle was smaller. The veins depicted by near-infrared light can be a landmark to identify great saphenous vein, and injury of the saphenous structure can be prevented using VeinViewer Flex or considering the insertion angle defined in this study when placing the suture button for syndesmosis injuries.Level of Evidence: Level IV.