Hideo Noguchi

Sonographic Appearance of the Flexor Tendon, Volar Plate, and A1 Pulley With Respect to the Severity of Trigger Finger

PURPOSE To evaluate trigger digits with sonography to determine morphological changes in the A1 pulley, flexor tendon, and volar plate in relation to the severity of triggering. METHODS We evaluated 67 trigger digits and graded them into 1 of 4 groups. We compared the groups according to severity and to contralateral fingers, which served as controls. RESULTS The thickness of the flexor tendons under the A1 pulley was proportional to the severity of triggering. The anteroposterior thickness of the flexor tendon increased significantly among the grades exhibiting triggering regardless of the affected digit. However, in digits other than the thumb, tendon thickness increased even in the absence of active triggering. Thickening tended to be greater with finger flexion. The A1 pulley exhibited the greatest thickness and the volar plate exhibited significant thickening in the group that exhibited continuous triggering that was easily reduced with active extension (grade III). CONCLUSIONS The flexor tendon thickened significantly before patients experienced triggering except in the thumb. In the thumb, the flexor tendon and A1 pulley thickened significantly only after patients exhibited triggering. Thickening of the volar plate appears to have an important role in continuous triggering. Although most clinicians can easily determine the severity of a trigger digit by clinical examination, ultrasound might be helpful for objectively understanding the severity and response to treatment, by examining the thickness of the flexor tendon and A1 pulley. In particular, sonographic measurement of the A1 pulley might be useful in judging the progression of trigger finger severity. In cases where a Doppler signal is detected inside the A1 pulley, more conservative therapies might be worth considering before surgery. TYPE OF STUDY/LEVEL OF EVIDENCE Diagnostic ΙΙΙ.

Posterior Condylar Offset Does Not Correlate With Knee Flexion After TKA

BackgroundStudies of medial and lateral femoral posterior condylar offset have disagreed on whether posterior condylar offset affects maximum knee flexion angle after TKA.Questions/purposesWe asked whether posterior condylar offset was correlated with knee flexion angle 1 year after surgery in (1) a PCL-retaining meniscal-bearing TKA implant, or in (2) a PCL-substituting mobile-bearing TKA implant.MethodsKnee flexion angle was examined preoperatively and 12 months postoperatively in 170 patients who underwent primary TKAs to clarify the effect of PCL-retaining (85 knees) and PCL-substituting (85 knees) prostheses on knee flexion angle. A quasirandomized design was used; patients were assigned to receive one or the other implant using chart numbers. A quantitative three-dimensional technique with CT was used to examine individual changes in medial and lateral posterior condylar offsets.ResultsIn PCL-retaining meniscal-bearing knees, there were no significant correlations between posterior condylar offset and knee flexion at 1 year. In these knees, the mean (± SD) postoperative differences in medial and lateral posterior condylar offsets were 0.0 ± 3.6 mm and 3.8 ± 3.6 mm, respectively. The postoperative change in maximum knee flexion angle was −5° ± 15°. In PCL-substituting rotating-platform knees, similarly, there were no significant correlations between posterior condylar offset and knee flexion 1 year after surgery. In these knees, the mean postoperative differences in medial and lateral posterior condylar offsets were −0.5 ± 3.3 mm and 3.3 ± 4.2 mm, respectively. The postoperative change in maximum knee flexion angle was −2° ± 18°.ConclusionsDifferences in individual posterior condylar offset with current PCL-retaining or PCL-substituting prostheses did not correlate with changes in knee flexion 1 year after TKA. We should recognize that correctly identifying which condyle affects the results of the TKA may be difficult with conventional radiographic techniques.Level of EvidenceLevel II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Changes in the Medial and Lateral Posterior Condylar Offset in Total Knee Arthroplasty

The purpose of this study was to clarify the changes between preoperation and postoperation in each posterior condylar offset (PCO) using computed tomography (CT) and to compare them to conventional radiographic (x-ray) evaluation in total knee arthroplasty. One hundred nine knees in 97 patients were evaluated. The medial PCO was significantly larger before surgery. The lateral PCO was significantly larger after surgery. Changes in the PCO on x-ray showed no significant correlation with the changes observed in the CT-evaluated medial (R = 0.028) and lateral PCO (R = 0.190). Changes in PCO observed by x-ray did not reflect those of the medial or lateral condyles on CT. We recommend CT-based evaluation of PCO by condyle when assessing the influence of PCO on range of motion following total knee arthroplasty.

Does mobile-bearing knee arthroplasty motion change with activity?

BACKGROUND The purpose of this study was to evaluate the effect of mobile-bearing implant design and activity on knee arthroplasty kinematics during three activities of daily living. METHODS In vivo kinematics were analyzed using 3D model registration from fluoroscopic images of non-weightbearing knee flexion-extension, weight-bearing squatting and stair activities in 20 knees in 10 patients with bilateral total knee arthroplasty. Each patient had one rotating-platform and one meniscal-bearing variant of the same prosthesis design. RESULTS Anteroposterior translations in meniscal-bearing knees were larger than those in rotating-platform knees for the different dynamic conditions. Meniscal-bearing knees showed more posterior femoral locations with activities that increased demand on the quadriceps. Condylar translations changed little in rotating-platform knees with different activities. CONCLUSIONS Activity dynamics can have a significant influence on knee kinematics, and have a greater effect on the kinematics of unconstrained meniscal-bearing prostheses than rotating-platform knee prostheses. LEVEL OF EVIDENCE Level II.

Safety and efficacy of a new tourniquet system

BackgroundIn upper limb surgery, the pneumatic tourniquet is an essential tool to provide a clean, bloodless surgical field, improving visualization of anatomical structures and preventing iatrogenic failure. Optimal inflation pressure to accomplish these objects without injuring normal tissue and inducing complications is not yet established. Use of the minimum tourniquet pressure necessary to produce a bloodless surgical field is preferable in order to prevent injury to normal tissue. Various methods have been implemented in an effort to lower effective cuff pressure. The purpose of this study is to report clinical experience with a new tourniquet system in which pressure is synchronized with systolic blood pressure (SBP) using a vital information monitor.MethodsWe routinely used the tourniquet system in 120 consecutive upper limb surgeries performed under general anaesthesia in our operating room instead of our clinic. Cuff pressure was automatically regulated to additional 100 mmHg based on the SBP and was renewed every 2.5 minutes intervals.ResultsAn excellent bloodless field was obtained in 119 cases, with the exception of one case of a 44-year-old woman who underwent internal screw fixation of metacarpal fracture. No complications, such as compartment syndrome, deep vein disorder, skin disorder, paresis, or nerve damage, occurred during or after surgery.ConclusionsThis new tourniquet system, synchronized with SBP, can be varied to correspond with sharp rises or drops in SBP to supply adequate pressure. The system reduces labor needed to deflate and re-inflate to achieve different pressures. It also seemed to contribute to the safety in upper limb surgery, in spite of rare unexpected oozing mid-surgery, by reducing tissue pressure.

Comparison of analog 2D and digital 3D preoperative templating for predicting implant size in total knee arthroplasty

The aim of this study was to compare the accuracy of preoperative templating in total knee arthroplasty (TKA) using conventional two-dimensional (2D) and computed tomography (CT)-based three-dimensional (3D) procedures, and to confirm the necessity of 3D evaluation for preoperative planning. One hundred consecutive primary TKAs were analyzed. Preoperative templating was performed for each TKA using both conventional 2D radiographs and a CT-based 3D image model created using KneeCAS software. Accuracies with regard to the predicted and actual implant sizes were determined for each procedure. The 3D procedure was found to be more accurate (59%) than the 2D procedure (56%) in predicting implant size, but the difference was not statistically significant (p = 0.67). Computer-assisted surgery systems are often used for preoperative planning in TKA. However, our results do not support the superiority of 3D preoperative templating over 2D conventional evaluation in predicting implant size. Thus, 3D templating may not be necessary for preoperatively predicting implant size in TKA, and can only be used as an approximate guide.

Biomechanical characteristics of nonbridging external fixators for distal radius fractures.

PURPOSE Nonbridging external fixation is becoming popular for distal radius fractures, although its biomechanical characteristics have not been documented. This study evaluated the biomechanical characteristics of nonbridging external fixators for distal radius fractures. METHODS We tested 3 currently available nonbridging fixators (F-Wrist fixator, Hoffman II Compact, and Pennig Dynamic Wrist Fixator) and determined their relative stiffness under axial compression, torsion, and bending moments (dorsal, volar, radial, and ulnar aspects) using a uniform unstable distal radius fracture model. The contact pressure and its total load on the fracture plane were also measured to evaluate the mechanical stimuli at the stable fracture site using a pressure-sensitive conductive rubber sensor. RESULTS Differences were observed in the stiffness: the Pennig fixator was the stiffest, whereas the F-Wrist fixator was the least rigid. The total load transmitted from the wrist joint to the fracture plane depended on the fixator stiffness in axial compression. CONCLUSIONS By determining the biomechanical characteristics of nonbridging external fixators, these data may help the clinician when deciding on a particular device for nonbridging external fixation.

Sonographic Analyses of Pulley and Flexor Tendon in Idiopathic Trigger Finger with Interphalangeal Joint Contracture

This study investigated the sonographic appearance of the pulley and flexor tendon in idiopathic trigger finger in correlation with the contracture of the interphalangeal (IP) joint in the thumb or proximal IP (PIP) joint in the other digits. Sonographic measurements using axial images were performed in 177 affected digits including 17 thumbs and 34 other digits judged to have IP or PIP joint contracture and 77 contralateral control digits. The A1 pulley of the contracture group was significantly thicker than that of the non-contracture group in all digits, whereas the flexor tendon was thicker only in digits other than the thumb. In the analysis using calculated cut-off values, A1 pulley thickening in the thumb and A1 pulley and flexor tendon thickening in the other digits showed statistically significant correlations with IP or PIP joint contracture. This study sonographically confirmed previous reports showing that enlargement of the flexor tendons contribute to the pathogenesis of PIP joint contracture.

Sonographic Appearance of the Pronator Quadratus Muscle in Healthy Volunteers

The purpose of this study was to investigate the sonographic appearance of the pronator quadratus muscle in healthy volunteers.

A New Tourniquet System that Determines Pressures in Synchrony With Systolic Blood Pressure in Total Knee Arthroplasty

This study reports the comparison of the clinical use of a new tourniquet system for total knee arthroplasty that can determine its pressure in synchrony with systolic blood pressure (SBP) with the conventional that keeps the initial setting pressure. We prospectively applied the additional pressure of 100 mm Hg based on the SBP recorded before skin incision to consecutive 72 procedures (conventional, initial 36; new, following 36). Six knees with the conventional and none of 5 with the new showed oozing blood in surgical field after sharp rise in SBP. Based on no statistically significant differences of the perioperative blood loss without any tourniquet-related postoperative complications in both groups, the new system seemed to be a practical device especially for controlling a bloodless surgical field.