Go Omori

Long-term results of non-operative treatment of anterior cruciate ligament injury.

We retrospectively reviewed the record of 89 patients with complete anterior cruciate ligament injury, documented by arthroscopic examination to investigate the long-term results in relation to the generation of osteoarthritis. The mean age of the patients was 34.9 years at follow-up and the mean duration of follow-up was 12.0 years. The mean Lysholm score was 89 points at follow-up. The mean Tegner activity score was 5.7 points before injury and 4.5 points at follow-up. Plain radiographs revealed 63% of osteoarthritis and 37% of which had joint space narrowing. The age of the patients, the level of sports activity, the history of meniscectomy, obesity and the osteoarthritis of the contralateral knee were found to be significant risk factors in osteoarthritis after anterior cruciate ligament injury. The most influential factor for osteoarthritis was considered meniscectomy, in combination with the risk factors of primary osteoarthritis. It should also be noted that modification of sports activity level was the most important factor for avoiding the combined injury of meniscus and osteoarthritis.

Bone tunnel enlargement after anterior cruciate ligament reconstruction using hamstring tendons.

We retrospectively reviewed 87 anterior cruciate ligament reconstructions using autogenous hamstring tendons with the Endobutton technique to investigate the relationship between bone tunnel enlargement and clinical outcome and to identify factors that contribute to the enlargement. The clinical outcome was evaluated using the Lysholm score and KT-1000 arthrometer. The location of the femoral tunnel with respect to Blumensaats line, the tibial tunnel with respect to the tibial plateau, and the angle between the femoral tunnel and Blumensaats line (femoral tunnel angle) were measured. Bone tunnel enlargement was observed in 32 patients (37%). Enlargement occurred in 22 of the femoral tunnels and 26 of the tibial tunnels. Enlargement of both tunnels occurred in 16 knees. There was no statistical difference in Lysholm scores or KT-1000 arthrometer measurements between the enlarged group and the unenlarged group. The femoral tunnel was placed more anteriorly in the enlarged femoral tunnel group than in the unenlarged femoral tunnel group. The tibial tunnel was placed more anteriorly in the enlarged tibial tunnel group than in the unenlarged tibial tunnel group. The femoral tunnel angle was significantly smaller in the enlarged femoral tunnel group than in the femoral unenlarged group. Gender, patient age, intraoperative isometricity, and graft size were not significant factors. Bone tunnel enlargement was not correlated with the clinical outcome measures. We conclude that the main factor associated with tunnel enlargement are the locations and angles of the tunnels. The windshield-wiper motion of the graft may be enhanced by changing tension in the graft due to tunnel malposition. An acute femoral tunnel angle may increase the mechanical stress on the anterior margin of the femoral tunnel.

Influence of the Femoral Tunnel Location and Angle on the Contact Pressure in the Femoral Tunnel in Anterior Cruciate Ligament Reconstruction

Background The causes of bone tunnel enlargement after anterior cruciate ligament reconstruction have not been thoroughly investigated. Hypothesis A malpositioned femoral tunnel and an acute femoral tunnel angle may increase the mechanical stress in the femoral tunnel. Study Design Controlled laboratory study. Methods Three femoral tunnels (normal, anterior, and acute) and the tibial tunnel were made in four fresh-frozen cadaveric knees. Aluminum cylinders containing pressure-sensitive conductive rubber sensors at the joint entrance were inserted into the femoral tunnels. Dynamic changes in the contact pressure of the graft in the femoral tunnel were measured. Results Peak contact pressures and dynamic changes in contact pressure for the normal and anterior femoral tunnels demonstrated no differences. Maximum contact pressure of the graft was observed at the anterior portion with the knee in full extension and at the posterior portion with deep knee flexion. Consistent contact pressure occurred at the anterior aspect of the acute femoral tunnel throughout the range of motion. Mean contact pressure at the anterior region of the acute femoral tunnel was significantly higher than that of the normal femoral tunnel at 60°, 90°, and 120° of knee flexion. Conclusions The consistent contact pressure in the anterior aspect of the acute femoral tunnel may erode the anterior portion of the femoral tunnel, resulting in bone tunnel enlargement. Clinical Relevance The femoral tunnel direction in anterior cruciate ligament reconstruction is an important factor in reducing femoral tunnel enlargement.

Three-dimensional lower extremity alignment in the weight-bearing standing position in healthy elderly subjects

BackgroundAlthough assessment of lower extremity alignment is important for the treatment and evaluation of diseases that present with malalignment of the lower extremity, it has generally been performed using only plain radiographs seen in two dimensions (2D). In addition, there is no consensus regarding the criteria for quantitative three-dimensional (3D) evaluation of the relative angle between the femur and tibia. The purpose of this study was to establish assessment methods and criteria for quantitatively evaluating lower extremity alignment in 3D and to obtain reference data from normal elderly subjects.MethodsThe normal alignment of 82 limbs of 45 healthy elderly subjects (24 women, 21 men; mean age 65 years, range 60–81 years) was analyzed in 3D with regard to flexion, adduction-abduction, and rotational angle of the knee in the weight-bearing, standing position. The obtained computed tomography (CT) and biplanar computed radiography (CR) data were used to define several anatomical axes of the femur and tibia as references.ResultsIn the sagittal plane, the mean extension-flexion angle was significantly more recurvatum in women than in men. In the coronal plane, the mean 3D hip-knee-ankle angle was more varus by several degrees in this Japanese series than that in a Caucasian series reported previously. Regarding rotational alignment, the mean angle between the anteroposterior axis of the tibia and the transepicondylar axis of the femur in this series was slightly larger (externally rotated) than that of previously reported Japanese series examined in the supine position.ConclusionsThese data are believed to represent important references for 3D evaluation of morbid lower extremity alignment in the weight-bearing, standing position and are important for biomechanical research (e.g., 3D analyses of knee kinematics) because the relative angles between the femur and tibia are assessed three-dimensionally.

Automated image registration for assessing three-dimensional alignment of entire lower extremity and implant position using bi-plane radiography.

An automated image-matching technique is presented to assess alignment of the entire lower extremity for normal and implanted knees and the positioning of implants with respect to bone. Sawbone femur and tibia and femoral and tibial components of a total knee arthroplasty system were used. Three spherical markers were attached to each sawbone and each component to define the local coordinate system. Outlines of the three-dimensional (3D) bone models and component computer-aided design (CAD) models were projected onto extracted contours of the femur, tibia, and implants in frontal and oblique X-ray images. Three-dimensional position of each model was recovered by minimizing the difference between the projected outline and the contour. Median values of the absolute error in estimating relative positions were within 0.5mm and 0.6 degrees for the femur with respect to the tibia, 0.5mm and 0.5 degrees for the femoral component with respect to the tibial component, 0.6mm and 0.6 degrees for the femoral component with respect to the femur, and 0.5mm and 0.4 degrees for the tibial component with respect to the tibia, indicating significant improvements when compared to manually obtained results.

Intra-articular hyaluronic acid injection versus oral non-steroidal anti-inflammatory drug for the treatment of knee osteoarthritis: a multi-center, randomized, open-label, non-inferiority trial

IntroductionWhile many of the commonly used conservative treatments for knee osteoarthritis (OA) have been recognized to be effective, there is still insufficient evidence available. Among the pharmacological treatments for knee OA, oral non-steroidal anti-inflammatory drugs (NSAIDs) act rapidly and are recommended for the management of OA. However, frequent and serious adverse effects of NSAIDs have been recognized. Intra-articular injections of hyaluronic acid (IA-HA) for the treatment of knee OA have been shown to reduce pain and improve joint function. However, there has been no qualified direct comparison study of the efficacy and safety between IA-HA and NSAIDs for patients with knee OA. The aim of this study was to clarify the efficacy and safety of early-phase IA-HA in comparison to those of NSAIDs for patients with knee OA.MethodsThis multicenter, randomized, open-label, parallel-group, non-inferiority comparison study with an oral NSAID involved a total of 200 patients with knee OA. An independent, computer-generated randomization sequence was used to randomly assign patients in a 1:1 ratio to NSAIDs three times per day for five weeks (n = 100) or IA-HA once a week for five weeks (n = 100). The primary endpoint was the percentage change in the patient-oriented outcome measure for knee OA, the Japanese Knee Osteoarthritis Measure (JKOM) score. All patients were questioned regarding any adverse events during treatment. The full analysis set (FAS) was used for analysis. The margin of non-inferiority was 10%.ResultsThe analyses of primary endpoint included 98 patients in the IA-HA group and 86 patients in the NSAID group. The difference in the percentage changes of the JKOM score between the two intervention arms (IA-HA; -34.7% (P<0.001), NSAID; -32.2% (P<0.001)) was -2.5% (95% confidence interval (CI): -14.0 to 9.1), indicating IA-HA was not inferior to NSAID. The frequency of both withdrawal and adverse events in the IA-HA group were significantly lower than those in the NSAID group (P = 0.026 and 0.004, respectively).ConclusionsThe early efficacy of IA-HA is suggested to be not inferior to that of NSAIDs, and that the safety of the early phase of IA-HA is superior to that of NSAIDs for patients with knee OA.Trial registrationUMIN Clinical Trials Registry (UMIN- CTR), UMIN000001026.

Obesity and osteoarthritis of the knee in women: results from the Matsudai Knee Osteoarthritis survey

Abstract A 14-year longitudinal study of middle-aged women was conducted to evaluate the role of obesity in the initiation and progression of idiopathic knee osteoarthritis and to investigate the effect of weight loss on its natural course. Of the 1191 women participating in the first Matsudai Knee Osteoarthritis Survey in 1979, 608 women without possible secondary osteoarthritis were re-evaluated in 1993. Data were collected by questionnaire, physical examination, and weight-bearing anteroposterior knee radiographs. The mean age of the subjects was 51.3 (range 40–65) years with mean body mass index (BMI) of 23.0 (range 16.0–34.7) at the first survey. Incident disease was defined if a grade 0 knee (a modified Kellgren and Lawrence scale) at the first survey advanced to grade 2 or higher at follow-up. Progression of the disease was defined if a grade 1 or 2 knee advanced to a higher grade at follow-up. We found that higher BMI at the first survey increased the risk of both the initiation and progression of knee osteoarthritis. Obese women (BMI≧25.0) with a decrease in body mass index of 2 units or more during the 14 years had a lower risk for radiological deterioration, although weight gain did not alter the risk significantly.

Contact pressure and three-dimensional tracking of unresurfaced patella in total knee arthroplasty

Abstract Ten fresh-frozen cadaver knees were studied to investigate the contact pressure distribution and three dimensional (3-D) tracking of the patella under consecutive three different conditions. They have included (a) an intact knee, (b) the unresurfaced patella in bicompartmental knee arthroplasty (Bi-TKA), and (c) the resurfaced patella in tricompartmental knee arthroplasty (Tri-TKA). A pressure-sensitive conductive rubber (PSR) sensor system was developed to measure the patellar contact pressure dynamically, and two sets of high resolution video cameras with direct linear transformation method was used to measure the 3-D patellar tracking. Total contact area on the patella was decreased in Bi-TKA, and further decreased in Tri-TKA. However, patellar contact area was significantly less in Tri-TKA than in the intact knee in 0 to 100 degrees of knee flexion ( P P

The effect of geometry of the tibial polyethylene insert on the tibiofemoral contact kinematics in Advance Medial Pivot total knee arthroplasty

BackgroundIn modern total knee arthroplasty (TKA), it is important to reproduce both medial pivot motion and posterior femoral rollback to obtain greater postoperative knee flexion. Several studies have reported the factors affecting knee motion and range of motion after TKA. The purpose of this study was to evaluate the effect of the tibial insert geometry on the tibiofemoral contact kinematics, especially focusing on the medial pivot motion and posterior femoral rollback.MethodsSeven cadaveric knees were replaced with the Advance Medial Pivot TKA, and two different geometries of polyethylene tibial insert, the standard medial pivot design (MP-design) and double high design (DH-design), were biomechanically compared. Four experimental configurations were evaluated in each specimen in this order: (1) the MP-design with posterior cruciate ligament (PCL) retaining, (2) the DH-design with PCL retaining, (3) the MP-design with PCL sacrificing, and (4) the DH-design with PCL sacrificing.ResultsUnder the PCL-retaining condition, both designs showed no medial pivot but bicondylar femoral rollback more than 60° of knee flexion. In the MP-design, tibiofemoral contact point (estimated contact point, ECP) of the medial compartment was located on the posterior lip of the ball-insocket structure while demonstrating greater than 120° of knee flexion. The posterior translation was also the same in both designs. On the other hand, ECP of the MP-design and the DH-design showed only medial pivot pattern under the PCL-sacrificing condition. In the DH-design, ECP of the lateral compartment showed paradoxical anterior translation from 0° to 60° of knee flexion. Total posterior translation was significantly greater in the lateral compartment than that in the medial compartment.ConclusionsThe results of this study suggest that in this type of TKA system the ball-in-socket geometry in the MP-design has an advantage for reproducing medial pivot motion in the PCL-sacrificing condition, and the flexion path structure in the DH-design is considered to be both effective and safe for femoral rollback in the PCL-retaining condition. However, neither design is sufficient to reproduce medial pivot motion and posterior femoral rollback. Therefore, a different design of tibial insert is needed for more physiological kinematics after TKA.

The effect of an ankle brace on the 3-dimensional kinematics and tibio-talar contact condition for lateral ankle sprains

Ten fresh-frozen cadaveric ankles were studied to investigate the effect of an ankle brace (Air-Stirrup) on the three-dimensional (3-D) motion and contact-pressure distribution of the talo-tibial joint with lateral ligamentous injury. Three-dimensional motion and contact-pressure distribution were simultaneously measured under dynamic conditions employing a direct linear-transformation technique and a dynamic-pressure sensor, respectively. Inversion increased significantly upon severing of the anterior talo-fibular (ATF) ligament and calcaneo-fibular (CF) ligaments; however, restoration to the intact level was observed following application of the ankle brace. Internal rotation also increased upon severing of the lateral ligaments in the plantar flexion; however, this difference was not altered by using the ankle brace. The contact area on the articular surface of the talus shifted from posterior to anterior between plantar flexion and dorsal flexion; additionally, a high pressure area was evident in the medial aspect of the talus following severing of the lateral ligaments. Upon application of the ankle brace, however, no significant changes were apparent in the contact condition. The results of this study suggest that stabilization against inversion is the major function of braces in terms of protection of ankle sprains. Ankle sprains, however, often occur in combinations of inversion, plantar flexion and internal rotation; therefore, restriction of plantar flexion and internal rotation may also be an important function of the ankle brace.