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Bone & Joint Open
Vol. 3, Issue 5 | Pages 390 - 397
1 May 2022
Hiranaka T Suda Y Saitoh A Tanaka A Arimoto A Koide M Fujishiro T Okamoto K

The kinematic alignment (KA) approach to total knee arthroplasty (TKA) has recently increased in popularity. Accordingly, a number of derivatives have arisen and have caused confusion. Clarification is therefore needed for a better understanding of KA-TKA. Calipered (or true, pure) KA is performed by cutting the bone parallel to the articular surface, compensating for cartilage wear. In soft-tissue respecting KA, the tibial cutting surface is decided parallel to the femoral cutting surface (or trial component) with in-line traction. These approaches are categorized as unrestricted KA because there is no consideration of leg alignment or component orientation. Restricted KA is an approach where the periarthritic joint surface is replicated within a safe range, due to concerns about extreme alignments that have been considered ‘alignment outliers’ in the neutral mechanical alignment approach. More recently, functional alignment and inverse kinematic alignment have been advocated, where bone cuts are made following intraoperative planning, using intraoperative measurements acquired with computer assistance to fulfill good coordination of soft-tissue balance and alignment. The KA-TKA approach aims to restore the patients’ own harmony of three knee elements (morphology, soft-tissue balance, and alignment) and eventually the patients’ own kinematics. The respective approaches start from different points corresponding to one of the elements, yet each aim for the same goal, although the existing implants and techniques have not yet perfectly fulfilled that goal.

Bone & Joint Research
Vol. 11, Issue 4 | Pages 226 - 228
20 Apr 2022
Hiranaka T Suda Y Saitoh A Koide M Tanaka A Arimoto A Fujishiro T Okamoto K

The Bone & Joint Journal
Vol. 102-B, Issue 3 | Pages 285 - 292
1 Mar 2020
Tanaka A Katagiri H Murata H Wasa J Miyagi M Honda Y Takahashi M


The aim of this study is to evaluate the clinical results of operative intervention for femoral metastases which were selected based on expected survival and to discuss appropriate surgical strategies.


From 2002 to 2017, 148 consecutive patients undergoing surgery for femoral metastasis were included in this study. Prognostic risk assessments were performed according to the Katagiri and revised Katagiri scoring system. In general, the low-risk group underwent resection and reconstruction with endoprosthetic replacement (EPR), while the high-risk group underwent internal fixation (IF) and radiation therapy. For the intermediate-risk group, the operative choice depended on the patient’s condition, degree of bone destruction, and radio-sensitivity. Overall survival, local failure, walking ability, and systemic complications were evaluated.

Bone & Joint Research
Vol. 5, Issue 6 | Pages 232 - 238
1 Jun 2016
Tanaka A Yoshimura Y Aoki K Kito M Okamoto M Suzuki S Momose T Kato H


Our objective was to predict the knee extension strength and post-operative function in quadriceps resection for soft-tissue sarcoma of the thigh.


A total of 18 patients (14 men, four women) underwent total or partial quadriceps resection for soft-tissue sarcoma of the thigh between 2002 and 2014. The number of resected quadriceps was surveyed, knee extension strength was measured with the Biodex isokinetic dynamometer system (affected side/unaffected side) and relationships between these were examined. The Musculoskeletal Tumor Society (MSTS) score, Toronto Extremity Salvage Score (TESS), European Quality of Life-5 Dimensions (EQ-5D) score and the Short Form 8 were used to evaluate post-operative function and examine correlations with extension strength. The cutoff value for extension strength to expect good post-operative function was also calculated using a receiver operating characteristic (ROC) curve and Fisher’s exact test.