Yasunari Ikuta

Unique Anatomic Feature of the Posterior Cruciate Ligament in Knees Associated With Osteochondritis Dissecans

Background: Osteochondritis dissecans (OCD) of the knee is a disorder in juveniles and young adults; however, its etiology still remains unclear. For OCD at the medial femoral condyle (MFC), it is sometimes observed that the lesion has a connection with fibers of the posterior cruciate ligament (PCL). Although this could be important information related to the etiology of MFC OCD, there is no report examining an association between the MFC OCD and the PCL anatomy. Purpose: To investigate the anatomic features of knees associated with MFC OCD, focusing especially on the femoral attachment of the PCL, and to compare them with knees associated with lateral femoral condyle (LFC) OCD and non-OCD lesions. Study Design: Case-control study; Level of evidence, 3. Methods: We retrospectively reviewed 39 patients (46 knees) with OCD lesions who had undergone surgical treatment. Using magnetic resonance imaging (MRI) scans, the PCL attachment at the lateral wall of the MFC was measured on the coronal sections, and the knee flexion angle was also measured on the sagittal sections. As with non-OCD knees, we reviewed and analyzed 25 knees with anterior cruciate ligament (ACL) injuries and 16 knees with meniscal injuries. Results: MRIs revealed that the femoral PCL footprint was located in a significantly more distal position in the patients with MFC OCD compared with patients with LFC OCD and ACL and meniscal injuries. There was no significant difference in knee flexion angle among the 4 groups. Conclusion: The PCL in patients with MFC OCD attached more distally at the lateral aspect of the MFC compared with knees with LFC OCD and ACL and meniscal injuries.

Added Value of Preoperative Computed Tomography for Determining Cartilage Degeneration in Patients With Osteochondral Lesions of the Talar Dome

Background: Osteochondral lesions of the talar dome (OLTs) involve the articular cartilage and subchondral bone. The subchondral bone plate (SBP) plays a crucial role in cartilage metabolism, and computed tomography (CT) can provide more precise information on subchondral bone. CT image prediction of the histological findings on OLT will be useful to determine the most appropriate therapeutic strategy. Purpose: To evaluate the unique features of the CT findings that relate to the condition of the articular cartilage in OLT. Study Design: Cohort study; Level of evidence, 3. Methods: Thirty ankles in 29 patients who had OLT with an osteochondral fragment were retrospectively reviewed. At surgery, the osteochondral fragment of 19 ankles could be preserved (preservation group) by fixation or drilling, and in the remaining 11 ankles, the osteochondral fragment was removed (excision group). Preoperative CT findings were compared between the 2 groups. Biopsies of the osteochondral fragment from 13 ankles were performed. The relationship between the CT and histological findings were evaluated. Results: The area of lesion in the preservation group was significantly larger than that in the excision group. The CT images of the lesion showed the rate of absorption of the SBP in the preservation group to be lower than that in the excision group. As for the lesion bed absorption, it was higher in the preservation group than in the excision group. All cases in the excision group showed bed sclerosis, compared with 42.1% in the preservation group. The specimens with disruption of the SBP exhibited cartilage degeneration and abundant chondrocyte cloning. OLT with absorption of the SBP on CT showed severe cartilage degeneration, while the remaining SBP on CT showed low-grade cartilage degeneration. Conclusion: This study shows the features of preoperative CT and histological findings in OLT with osteochondral fragments. The condition of the SBP affects the cartilage degeneration. CT findings provide important information for the determination of surgical treatment.

In Vivo Kinetics of Mesenchymal Stem Cells Transplanted into the Knee Joint in a Rat Model Using a Novel Magnetic Method of Localization

We have developed a magnetic system for targeting cells in minimally invasive cell transplantation. Magnetically labeled MSCs (m‐MSCs) with nanoscale iron particles can be guided into the desired region by magnetic force from an extracorporeal device. We reported that magnetic targeting of m‐MSCs enhances cartilage repair in a mini‐pig model. However, the detailed kinetics of these magnetically targeted m‐MSCs remain unknown. For clinical use, this aspect should be clarified from a safety standpoint. We therefore investigated the spatial and temporal distribution of the fluorescently‐labeled m‐MSCs transplanted into the knee joint using in vivo fluorescence combined with three‐dimensional computed tomographic imaging in a rat model. Although the intraarticularly injected m‐MSCs were spread throughout the joint cavity in the absence of magnetic force, the magnetic force caused the injected m‐MSCs to accumulate around the chondral lesion. Further examinations including ex vivo imaging, histological assessments and reverse transcription polymerase chain reaction revealed that transplanted MSCs were not present in any major organs after intraarticular administration, regardless of magnetic targeting. Our data suggest that m‐MSCs can be accumulated efficiently into a chondral lesion using our magnetic targeting system, while none of the intraarticularly transplanted MSCs migrate to other major organs.

Relationship Between Bone Marrow Lesions on MRI and Cartilage Degeneration in Osteochondral Lesions of the Talar Dome

Background: In the evaluation of osteochondral lesions of the talar dome (OLT), bone marrow lesions (BML) are commonly observed in the subchondral bone on magnetic resonance imaging (MRI). However, the significance of BML, such as the histology of the overlying cartilage, is still unclear. The purpose of this study was to investigate the relationship between the BML and cartilage degeneration in OLT. Methods: Thirty-three ankles with OLT were included in this study. All ankles underwent CT and MRI and had operative treatment. The ankles were divided into 2 groups, depending on the presence of bone sclerosis (ie, with or without) in the host bone just below the osteochondral fragment (nonsclerosis group and sclerosis group). The area of BML was compared between the 2 groups. Biopsies of the osteochondral fragment from 20 ankles were performed during surgery, and the correlation between the BML and cartilage degeneration was analyzed. The remaining 13 ankles had the CT and MRI compared with the arthroscopic findings. Results: The mean area of BML in the nonsclerosis group was significantly larger than that in the sclerosis group. In the histologic analysis, there was a significant and moderate correlation between the Mankin score and the area of BML. The mean Mankin score in the nonsclerosis group was significantly lower than that in the sclerosis group. Conclusions: This study revealed that a large area of BML on MRI exhibited low degeneration of cartilage of the osteochondral fragment, while a small area of BML indicated sclerosis of the subchondral bone with severe degeneration of cartilage. The evaluation of BML may predict the cartilage condition of the osteochondral fragment. Level of Evidence: Level III, comparative series.

Evaluation of Articular Cartilage Injury Using Computed Tomography With Axial Traction in the Ankle Joint

Background: Although chondral or osteochondral injuries are usually assessed by magnetic resonance imaging, its accuracy can be low, presumably related to the relatively thin cartilage layer and the close apposition of the cartilage of the talus and tibial plafond. We hypothesized that axial traction could provide a contrast between the articular cartilage and joint cavity, and it enabled the simultaneous evaluation of cartilage and subchondral bone. The purpose of this study was to assess the feasibility of using computed tomography (CT) imaging with axial traction for the diagnosis of articular cartilage injuries. Methods: Chondral lesions in 18 ankles were evaluated by CT with axial traction using a tensioning device and ankle strap for enlargement of the joint space of the ankle. CT was done in 3-mm slices and programmed for gray scale, and then CT images were allocated colors to make it easier to evaluate the cartilage layer. The International Cartilage Repair Society (ICRS) grades on CT were compared with those on arthroscopic findings. Results: The respective sensitivity and specificity of CT imaging with traction using ICRS grading were 74.4%, and 96.3%. The level of agreement of the ICRS grading between CT images and arthroscopic findings was moderate (kappa coefficient, 0.547). Adding axial traction to CT increased the delineation of the cartilage surface, including chondral thinning, chondral defect, and cartilage separation. Conclusions: CT with axial traction produced acceptable levels of sensitivity and specificity for the evaluation of articular cartilage injuries, in addition to the assessment of subchondral bone. Level of Evidence: Level III, comparative case series.

A Technique for the Reduction of Complications Associated With Anterior Portal Placement During Ankle Arthroscopy Using a Peripheral Vein Illumination Device

Ankle arthroscopy is a minimally invasive technique for ankle joint treatment. However, injury to the intermediate dorsal cutaneous nerve (IDCN) and the medial dorsal cutaneous nerve (MDCN) is a common complication during anterior portal placement. To prevent injuries, methods such as palpating the nerves topographically and marking the nerves by transilluminating the skin with an arthroscope have been proposed. Easier and more definitive methods of identifying the IDCN and MDCN should result in a reduction of complications. Recently, a vein imaging system was developed that projects images of subcutaneous vasculature directly onto the skin with the use of near-infrared (NIR) light. Because anatomic studies have shown that superficial veins accompany the IDCN and MDCN, protecting the subcutaneous veins could lower the risk of nerve injury. We introduce our technique for the creation of an ankle arthroscopic portal using an NIR imaging system, which displays the vein image on the skin, to prevent injury to the superficial veins and, consequently, reduce IDCN and MDCN injuries. This is the first technical report on the prevention of vein and nerve injuries using an NIR imaging system. Our technique for avoiding vein injury using a peripheral vein illumination device during anterior portal placement in ankle arthroscopy could lower the risk of complications.

A novel functional correction method for habitual patellar dislocation using autologous hamstring tendon: a case report

Habitual patellar dislocation is an uncommon condition. In this case, a patient demonstrated lateral patellar dislocation in the middle or terminal range of flexion. A functional correction of the patella was devised so that the fixation site of the autologous graft on the femur was able to stabilize the patella selectively during the middle or terminal range of flexion. It is not the anatomical medial patellofemoral ligament attachment of the femur that is essential, but that a relevant fixation point on the femur should be sought in each patient to obtain stabilization of the patella to reverse habitual patellar dislocation.

Anatomic feature of deltoid ligament attachment in posteromedial osteochondral lesion of talar dome

BACKGROUND Osteochondral lesions of the talus (OLT) are recognized as being commonly associated with trauma. However, the etiology of OLT remains unclear. In the case of a posteromedial lesion of OLT (medial OLT), the deep layer of the deltoid ligament is located close to the medial OLT, and this relationship between a medial lesion and deltoid ligament could be a risk factor for medial OLT. The purpose of this study is to investigate the unique anatomic feature of the deep deltoid attachment to the talus in patients with medial OLT compared with patients with non-medial OLT. METHODS Forty ankles with medial OLT and 40 ankles without medial OLT were retrospectively reviewed in this study. On the coronal images of MRI, the attachment of deltoid ligament was measured. The continuity of the osteochondral fragment and its bed was evaluated on MRI and arthroscopic findings. RESULTS Coronal MRI images showed that the attachment of the deep deltoid ligament to the medial OLT was broader and located more proximally than in non-medial OLT. The continuity of fibers from the insertion site of deltoid ligament to the talus to the osteochondral fragment was observed (76.7%). In the arthroscopic findings, the osteochondral fragment was obviously connected to the talus at the medial site in 85.2% of feet. CONCLUSIONS The location of the deep deltoid ligament attachment to the medial OLT was more proximal and there was the possibility of these anatomic feature might contribute to the pathogenesis of medial OLT.