Tsutomu Kawano

The accuracy of image-guided knee replacement based on computed tomography.

Our study evaluated the accuracy of an image-guided total knee replacement system based on CT with regard to preparation of the femoral and tibial bone using nine limbs from five cadavers. The accuracy was assessed by direct measurement using an extramedullary alignment rod without radiographs. The mean angular errors of the femur and tibia, which represent angular gaps from the real mechanical axis in the coronal plane, were 0.3 degrees and 1.1 degrees, respectively. The CT-based system, provided almost perfect alignment of the femoral component with less than 1 degrees of error and excellent alignment with less than 3 degrees of error for the tibial component. Our results suggest that standardisation of knee replacement by the use of this system will lead to improved long-term survival of total knee arthroplasty.

The Oblique Posterior Femoral Condylar Radiographic View Following Total Knee Arthroplasty

BACKGROUND It is often difficult to evaluate the posterior aspects of the femoral condyles after total knee arthroplasty. We have developed an imaging technique involving the use of the oblique posterior condylar view for the evaluation of the posterior aspects of the femoral condyles. The purpose of the present study was to compare the efficacy of this view with that of the true-lateral view. METHODS Three orthopaedic surgeons analyzed fifty-five sets of radiographs (consisting of oblique posterior condylar and true-lateral views) for patients who had undergone total knee arthroplasty. The accuracy and reproducibility of the oblique posterior condylar view for the detection of radiolucencies were compared with those of the true-lateral view. RESULTS The oblique posterior condylar view was significantly better than the true-lateral view for the detection of radiolucencies of the posterior aspects of the femoral condyles (p < 0.0005). CONCLUSIONS Radiographic analysis with use of the oblique posterior condylar view is technically easy and is accurate for the evaluation of radiolucencies of the posterior aspects of the femoral condyles after total knee arthroplasty.

Varus–valgus laxity correlates with pain in osteoarthritis of the knee

Pain during osteoarthritis (OA) of the knee does not necessarily correlate with the severity of the radiographic grade, and the mechanism of pain has not been completely clarified. The purpose of this study was to evaluate risk factors for pain in the knee OA using epidemiologic analyses. We evaluated 518 out of 4183 people over the age of 40 (156 males and 362 females) from Shinyoshitomi village, Japan. Mean ages were 63.8 years for men and 60.7 years for women. Screening included a physical examination of the knee and a standing AP roentgenogram of the bilateral knee. Radiographic OA was defined as a Kellgren-Lawrence grade 2 or higher. All data were coded and pain risk factors were evaluated using a multiple logistic regression model. Radiographic OA was observed in 18.4% of men and 26% of women. Of these subjects with OA, 10.9% of men and 32.5% of women complained of knee pain. Seven factors-age, gender, BMI, radiographic grade, varus-valgus laxity, torque of quadriceps muscles, and varus-valgus alignment-were evaluated as potential risk factors for pain. A significant increase in the odds ratio was observed with varus-valgus laxity (p=0.005; odds ratio, 3.04). Our results suggest that varus-valgus laxity is a risk factor for pain during knee OA.

Validity of an oblique posterior condylar radiographic view for revision total knee arthroplasty

We have previously developed a radiographic technique, the oblique posterior condylar view, for assessment of the posterior aspect of the femoral condyles after total knee arthroplasty. The purpose of this study was to confirm the validity of this radiographic view based upon intra-operative findings at revision total knee arthroplasty. Lateral and oblique posterior condylar views were performed for 11 knees prior to revision total knee arthroplasty, and radiolucent lines or osteolysis of the posterior aspect of the femoral condyles were identified. These findings were compared with the intra-operative appearance of the posterior aspects of the femoral condyles. Statistical analysis showed that sensitivity and efficacy were significantly better for the oblique posterior condylar than the lateral view. This method can, therefore, be considered as suitable for routine follow-up radiographs of the femoral component and in the pre-operative planning of revision surgery.

Two subtypes of radiographic osteoarthritis in the distal interphalangeal joint of the hand.

BackgroundThe etiology and pathogenesis of hand osteoarthritis (OA) are not completely clarified, and several factors may cooperate in a multifactorial fashion in its development. The purpose of this study was to clarify the effects of the dominant hand that contribute to the development of distal interphalangeal (DIP) joint OA using epidemiological analyses.MethodsA total of 518 subjects (156 men, 362 women) in a rural community were analyzed. Their mean age was 63.8 years for men and 60.7 years for women. Anteroposterior (AP) standing radiographs of bilateral knees, lateral views of the lumbar spine, and AP views of bilateral hands were obtained. Furthermore, a survey of their life patterns was conducted using self-administered questionnaires. Radiographic osteoarthritis was defined as Kellgren and Lawrence grade 2 or higher. Hand OA was limited to Heberden’s nodes. Generalized OA (GOA) was defined as bilateral knee OA plus lumbar spine OA.ResultsGOA was observed in 13.0% of the subjects. The incidence of DIP joint OA was significantly higher in the GOA group than that in the non-GOA group. In the GOA group, the incidence of right-hand DIP joint OA in right-handed and left-handed subjects was 37.5% and 40.0%, respectively, without a significant difference. In the non-GOA group, however, the incidence of right-hand DIP joint OA in right-handed and left-handed subjects was 16.4% and 3.2%, respectively, with a significant difference. With a multiple logistic regression model, the P value of the handedness was marginal (0.060), but a clear tendency of increase in the odds ratio (7.129) was observed in the dominant hand for the non- GOA group. In contrast, there was no effect of the handedness on right-hand DIP joint OA in the GOA group.ConclusionsThere are two subtypes of hand DIP joint OA in terms of the etiology. One is environmental, and the other is genetic.

Influence of Age on Healing Capacity of Acute Tears of the Anterior Cruciate Ligament Based on Magnetic Resonance Imaging Assessment.

Objective The purpose of this study was to evaluate the influence of patient age on the effects of conservative treatment of the anterior cruciate ligament (ACL). Methods A total of 102 consecutive patients with acute ACL injury were allowed to heal without surgery. Final magnetic resonance imaging images of the ACL were classified from grade I, indicating good morphological recovery, to grade IV, indicating poor recovery. Chi-square analysis was used to determine significant differences in the incidence of grades I and II among those less than 20 versus those 20 years or more of age. Results The mean follow-up to final magnetic resonance imaging was 9 months. A significant difference in the frequency of grades I and II was observed between age groups (<20 years, 13.0%; ≥20 years, 69.6%; P < 0.0001). Conclusion ACL injury was more severe, and morphological recovery with conservative treatment was poorer among younger patients than among adults.