Yutaka Kinoshita, Toshinori Sakai, Shoichiro Takao, Akihiro Nagamachi, Yasuhiro Takahashi and Koichi Sairyo : Usefulness of CT-like Bone Contrast MRI in the Treatment of Atlantoaxial Rotatory Fixation: A Report of 3 Cases., JBJS Case Connector, 16, 1, 2026.
(要約)
Three-dimensional atlantoaxial rotatory fixation (AARF) is usually evaluated by computed tomography (CT). This report describes 3 cases of AARF that were diagnosed and treated based on CT-like bone contrast magnetic resonance imaging (CTLBC MRI) findings. Three-dimensional volume rendering CTLBC MRI scans helped with diagnosis and treatment planning.CTLBC MRI can determine the severity of dislocation and C1/C2 facet deformity in AARF and inform the treatment strategy. CTLBC MRI may reduce ionizing radiation exposure in children and merits broader evaluation.Case series, Level V.
Yasuaki Tamaki, Daisuke Hamada, Keizo Wada, Shota Shigekiyo, Yuto Sugimine, Yutaka Kinoshita, Koichi Tomita and Koichi Sairyo : Comparison of methods for evaluating soft tissue balance in robotic-assisted total knee arthroplasty: A cadaveric study., The Knee, 58, 2026.
(要約)
Robotic-assisted total knee arthroplasty (TKA) can simulate postoperative soft tissue balance based on three-dimensional positional information for the prosthesis and preoperative soft tissue balance data. However, the accuracy of soft tissue balance data obtained during robotic-assisted TKA is unclear. This study aimed to compare the reproducibility of three different assessment methods for soft tissue balance in robotic-assisted TKA and to examine the influence of examiner experience.Seven fresh-frozen cadavers were used. Three examiners assessed the medial and lateral gaps by applying a continuous varus/valgus load to the knee throughout the full range of motion using an image-free system (Navio). Soft tissue balance was evaluated by applying mild manual stress (mild group), maximum manual stress (max group), and a Z-retractor (Z group). Each examiner performed the procedure twice, and intra-rater and inter-rater reliability was evaluated using the intraclass correlation coefficient (ICC).In medial gap assessment, the ICCs for intra-rater reliability ranged from 0.88 to 0.95 in the mild group, 0.89 to 0.94 in the max group, and 0.89 to 0.95 in the Z group, with respective ICCs of 0.88, 0.88, and 0.92 for inter-rater reliability. In lateral gap assessment, the ICCs for intra-rater reliability ranged from 0.37 to 0.66 in the mild group, 0.33 to 0.86 in the max group, and 0.62 to 0.96 in the Z group, with respective ICCs of 0.41, 0.24, and 0.57 for inter-rater reliability.Intra-rater and inter-rater reliability was high for the medial gap assessment but lower for the lateral gap assessment.
(キーワード)
Humans / Arthroplasty, Replacement, Knee / Robotic Surgical Procedures / Cadaver / Reproducibility of Results / Range of Motion, Articular / Knee Joint / Aged / Male / Female
Yutaka Kinoshita, Toshinori Sakai, Kosuke Sugiura, Takahisa Kurosaki, Jiro Kobayashi, Saori Soeda, Yasuaki Tamaki, Masatoshi Morimoto, Hiroaki Manabe, Fumitake Tezuka, Kazuta Yamashita and Koichi Sairyo : Can MRI Replace CT in the Diagnosis and Staging of Lumbar Spondylolysis in Pediatric Patients? A Validation Study Using MR Bone Imaging, Journal of Pediatric Orthopedics, 46, 1, e56-e60, 2025.
(要約)
Magnetic resonance (MR) bone imaging may reduce radiation exposure compared with computed tomography (CT) in staging lumbar spondylolysis. This study aimed to validate the consistency between MR bone imaging and CT. We retrospectively investigated short tau inversion recovery (STIR), MR bone imaging, and CT scans of patients diagnosed with lumbar spondylolysis who underwent MRI and CT scans within 2 weeks between November 2021 and March 2023.We identified 190 fractures in 968 pars interarticularis of 105 patients. MR bone imaging was based on Siemens 3 Tesla T1-weighted volumetric interpolated breath-hold imaging (T1 VIBE). The CT-based staging and T1 VIBE-based staging were matched [incomplete fracture, complete fracture, gap of 2 mm (gap)]. For fracture detection with CT as a reference, the respective sensitivity, specificity, and accuracy were 94%, 99%, and 99% for incomplete fracture, 74%, 100%, and 98% for complete fracture, 81%, 99%, and 99% for gap, and 97%, 100%, and 100% for any fracture. When we assessed 62 pars with complete fracture or a gap, the rates were 91%, 100%, and 99%, respectively. In staging 190 fractures with CT as a reference, the respective sensitivity, specificity, and accuracy were 94%, 91%, and 93% for incomplete fracture, 74%, 96%, and 91% for complete fracture, 81%, 96%, and 95% for gap, and 97%, 100%, and 97% for any fracture. The respective values were 91%, 98%, and 96% for complete fracture combined with gap. Of 153 pedicles with high signal change on STIR, 10 showed no fracture line, 110 showed incomplete fracture lines, 30 showed complete fracture lines, and 3 showed a gap on T1 VIBE, compared with 5, 109, 39, and 0, respectively, on CT. The T1 VIBE sequence is highly accurate, although it has some limitations in fracture detection. T1 VIBE can be used clinically in conjunction with STIR and may replace CT in determining the treatment strategy for lumbar spondylolysis, resulting in reduced medical radiation exposure to pediatric patients. Level III diagnostic study.