Akihiko Toda

Post-cam clunk syndrome after posterior stabilized total knee arthroplasty as a sign of early femoral component loosening

Soft tissue impingements are well-known complications of total knee arthroplasty. The impingements usually occur between the medial or lateral femoral component and tibial insert, and between the patella and femoral components. We report a rare case of impingement of the soft tissue between the femoral intercondylar fossa and post of the polyethylene insert, which caused pain and walking disability. After the surgery for the arthroscopic removal of the soft tissue, the symptoms disappeared. However, prosthetic loosening of the femur occurred several months after the arthroscopic surgery, requiring revision surgery. We would propose to call this symptom as post-cam clunk syndrome.

Inaccurate rotational component position in image-free navigated unicompartmental knee arthroplasty

Background/Objective The success of unicompartmental knee arthroplasty (UKA) is highly dependent on the accuracy of component and leg alignment. Computer-assisted surgery is gaining popularity in total knee arthroplasty with numerous studies reporting improved accuracy and decreased variability in implant position and postoperative limb alignment compared with conventional techniques. However, literature evaluating the accuracy of computer-navigated UKA is limited. Therefore, this study aimed to investigate the accuracy of component positions in navigated UKA using a three-dimensional (3D) image-matching system. To the best of our knowledge, this study is the first to evaluate the accuracy of implant-placement position in UKA using 3D image-matching systems. Methods Twenty-three knees in 22 patients (9 men, 13 women) underwent computer-assisted UKA performed by a senior surgeon from 2011 to 2013. All surgeries were performed with measured resection techniques using an image-free-navigation system. We recorded the coronal, sagittal, and rotational bone-resection angles towards the mechanical axis in the distal femur and proximal tibia using image-free navigation intraoperatively. The coronal, sagittal, and rotational alignments of the femoral and tibial components were also measured using the 3D image-matching system, and the accuracy of the navigated UKA was evaluated. The rotational alignment of the femur and tibia was defined as surgical epicondylar axis and Akagis line, and a deviation over 3° from the AA was defined as an outlier. Results We observed coronal outliers for the femoral component in four of the 23 patients, and for the tibial component in three of the 23 patients. We also observed sagittal outliers for the femoral component in five of 23 patients, and for the tibial component in three of the 23 patients. Twenty-two tibial components were placed in external rotation relative to the rotational reference line. Conclusion In both coronal and sagittal alignments, there were a definite proportion of outliers. The ratio of outliers in rotational alignment was especially higher than that in coronal and sagittal alignments. In UKA, the identification of bony landmarks is difficult because of the small operation field. Therefore, careful surface mapping of particular bony landmarks is necessary, and it is not enough to use image-free navigation system in UKA.

Surgical management of the peroneus quartus muscle for bilateral ankle pain: a case report.

The peroneus quartus muscle is an accessory muscle seen in the lateral compartment of the lower leg. Although the peroneus quartus muscle is asymptomatic in general, it sometimes becomes pathologic. We present the rare case of bilateral ankle pain with crepitation caused by the peroneus quartus muscle. Magnetic resonance imaging should be considered to assist with diagnosing this condition. Foot and ankle surgeons should consider it in the preoperative differential diagnosis when patients present with posterior ankle pain.

Quantitative Evaluation of Patient Specific Instrument for Total Knee Arthroplasty

Patient specific instruments (PSI) system has been attracting considerable attention for navigation-free surgical operation of total knee arthroplasty (TKA). PSI is a jig which guides a cutting section of the femoral or the tibia bones where TKA implant is attached to ensure accurate and reproducible surgery, and is prepared for a specific patient. However, another problem has been raised because the attachment of PSI will cause errors of TKA guidance. This paper proposes a novel system to evaluate the accuracy of attaching PSI during TKA operation using cone-beam CT. The system acquires 3-D sectional images of PSI attached to knee, and evaluates the attachment accuracy by means of image registration techniques with computer-aided design (CAD). It calculates the position and the angle of guidance pin, and compares with the preoperative planning. The system has been applied to three subjects which had been operated TKA with PSI. The results produced 3-D renderings of the attached PSI and of the planned PSI, and calculated angle differences between the attached and the planned guidance pin. By using them, we can evaluate the attachment accuracy of PSI, and also evaluate the implanting accuracy of TKA.

Image-based Evaluation of Patient Specific Instrument Attachment in TKA☆

Abstract Patient specific instruments (PSI) system has been attracting considerable attention for navigation-free surgical operation of total knee arthroplasty (TKA). PSI is a jig which guides a cutting section of the femoral or the tibia bones where TKA implant is attached to ensure accurate and reproducible surgery, and is prepared for a specific patient. However, another problem has been raised because the attachment of PSI will cause errors of TKA guidance. This paper proposes a novel system to evaluate the accuracy of attaching PSI during TKA operation using cone-beam CT. The system acquires 3-D sectional images of PSI attached to knee, and evaluates the attachment accuracy by means of image registration techniques with computer-aided design (CAD). It calculates the position and the angle of guidance pin, and compares with the preoperative planning. The system has been applied to three subjects which had been operated TKA with PSI. The results produced 3- D renderings of the attached PSI and of the planned PSI, and calculated angle differences between the attached and the planned guidance pin. By using them, we can evaluate the attachment accuracy of PSI, and also evaluate the implanting accuracy of TKA.