Shoulder and elbow pain in junior high school baseball players: Results of a nationwide survey.

BACKGROUND: Despite proposals and guidelines to prevent baseball injuries in young players by societies and organizations, many shoulder and elbow injuries continue to occur among junior high school baseball players. In order to investigate the training conditions of junior high school baseball players and the risk factors for shoulder and elbow pain in the players, we conducted a questionnaire survey among junior high school baseball players throughout the country. METHODS: The questionnaire survey was conducted among junior high school baseball players in September 2016. RESULTS: A total of 11,134 junior high school baseball players belonging to 495 teams responded to the survey. Among these, 4004 players trained every day of the week and 1151 players played baseball games every month with no off-season. Among 9752 players who did not have shoulder and/or elbow pain in the spring and summer of 2015, 19.2% of players experienced elbow pain over the course of one year, 13.6% of players experienced shoulder pain, and 28.0% complained of shoulder and/or elbow pain. The frequency of elbow pain was more than that of shoulder pain. At risk for shoulder pain were pitchers and catchers and second-year students, while risk factors for elbow pain were playing pitcher and catcher positions, pitching or throwing ≥300 balls per week, playing ≥10 games on average per month and being left-handed. CONCLUSION: Risk factors for shoulder pain were different from those for elbow pain. To prevent elbow pain, coaches should pay attention to pitchers and catchers and left-handed players and not allow players to pitch or throw ≥300 full-power balls per week or participate in ≥10 games per month. They should also pay attention to pitchers and catchers and second-year students to prevent shoulder pain. It is important for coaches to train multiple pitchers and catchers.

Shoulder and elbow pain in elementary school baseball players: The results from a nation-wide survey in Japan.

BACKGROUND: Despite recommendations on how to prevent baseball injuries in youths by the Japanese Society of Clinical Sports Medicine, shoulder and elbow pain still frequently occurs in young baseball players. We conducted a questionnaire survey among baseball players at elementary schools across the country to understand the practice conditions of players, examining the risk factors of shoulder and elbow pain in baseball players. METHODS: The questionnaire survey was conducted among elementary school baseball players as members of the Baseball Federation of Japan in September 2015. RESULTS: A total of 8354 players belonging to 412 teams (average age: 8.9) responded to the survey. Among 7894 players who did not have any shoulder and/or elbow pain in September 2014, elbow pain was experienced in 12.3% of them, shoulder pain in 8.0% and shoulder and/or elbow pain in 17.4% during the previous one year. A total of 2835 (39.9% of the total) practiced four days or more per week and 97.6% practiced 3 h or more per day on Saturdays and Sundays. The risk factors associated shoulder and elbow pain included a male sex, older age, pitchers and catchers, and players throwing more than 50 balls per day. CONCLUSIONS: It has been revealed that Japanese elementary school baseball players train too much. Coaches should pay attention to older players, male players, pitchers and catchers in order to prevent shoulder and elbow pain. Furthermore, elementary school baseball players should not be allowed to throw more than 50 balls per day. STUDY DESIGN: Retrospective cohort study.

Anterior Cruciate Ligament Reconstruction Does Not Fully Restore Normal 3D Knee Kinematics at 12 Months During Walking and Walk-Pivoting: A Longitudinal Gait Analysis Study.

The purpose of the current study was to longitudinally evaluate how preoperative knee kinematics change after ACL reconstruction. Three-dimensional gait analysis using the point cluster method was undertaken on the same subjects preoperatively and at 3, 6, and 12 months after ACL reconstructive surgery. Thirteen subjects (7 males, 6 females) were examined while performing 2 different activities at self-selected speeds: walking and walk-pivoting (walking, pivoting toward the landed limb side and walking away). The contralateral knees of subjects at 12 months postoperatively were selected as control knees. Flexion range in the stance phase increased with time after surgery, but remained lower than in the contralateral knee, even at 12 months postoperatively (P < .05) during walking and walk-pivoting. The rotation pattern during walking and walk-pivoting showed an offset toward external rotation by 6 months postoperatively compared with control knees, while at 12 months postoperatively the offset had nearly disappeared and the movement pattern resembled that in control knees. These findings suggest that a return to sport participation by 6 months after ACL reconstruction requires careful consideration. Depending on the type of sport, activity restriction even after 12 months may need to be considered to allow complete kinematic restoration.

Asymmetry of the knee extension deficit in standing affects weight-bearing distribution in patients with bilateral end-stage knee osteoarthritis.

PURPOSE: The aim of this study was to evaluate weight-bearing distribution in patients with bilateral end-stage knee osteoarthritis (OA) and to clarify the gait parameters affecting the weight-bearing distribution during both standing and walking using gait analysis. METHODS: Twenty-five patients (averaged 71 years) with symptomatic bilateral end-stage medial knee OA participated in this study. They performed relaxed standing, placing one foot on a force plate and thereafter, level walking. First, knee resultant force was calculated on bilateral knees during standing. The knees in each patient were divided into Higher and Lower force side for the definition of dominant side limb. Second, gait parameters in each subject were compared between both sides. RESULTS: Each patient had large weight-bearing asymmetry, though passive range of motion, subjective pain level, femorotibial angle and radiographic disease severities were not significantly different between both sides. In standing, knees on Higher force side were significantly extended (11.2 ± 6.5°) than on Lower force side (14.4 ± 7.3°, P = 0.0086). Similarly, knees on Higher force side were also significantly extended at heel strike during gait. Besides, peak values of extension moment, knee adduction moment, knee adduction moment impulse and vertical force during gait were significantly greater on Higher force side. CONCLUSIONS: Ability to extend the knee in standing was considered to be an essential factor to decide loading condition. It is clinically important to examine the ability to extend the knee in standing when considering loading asymmetry during gait in patients with bilateral knee OA. LEVEL OF EVIDENCE: III.

Asymmetry of the leg alignment affects trunk bending in the coronal plane after unilateral total knee arthroplasty.

Unilateral total knee arthroplasty (TKA) would produce asymmetric changes of lower extremity in patients with bilateral varus deformity. Our purpose was to investigate whether asymmetry of the leg alignment would affect trunk bending in the coronal plane after unilateral TKA. Twenty patients (mean 76 years old) with bilateral end-stage knee osteoarthritis (OA) participated. Spine images during relaxed standing were obtained on pre- and postoperative day 21. As a result, the shoulder tilted more to the TKA side and the pelvis inclined more to the contralateral OA side. These results suggested that the trunk would bend away from the contralateral OA side after unilateral TKA in patients with bilateral end-stage knee OA and varus deformity. Asymmetry of the leg alignment led to asymmetric trunk bending.

Bilateral Medial and Lateral Discoid Menisci: A Case Report.

Introduction: A discoid meniscus is a typical anatomical variation of the knee. There are several cases of either lateral or medial discoid menisci; however, their combination is rare. We describe a rare instance of bilateral discoid medial and lateral menisci. Case Report: A 14-year-old boy who developed left knee pain after twisting his knee at school was referred to our hospital. He had limited extension of -10°, lateral clicking, and pain on the McMurray test in the left knee and complained of slight clicks in the right knee. Magnetic resonance imaging results for both knees revealed discoid medial and lateral menisci. Surgery was performed on the symptomatic left knee. Arthroscopically, a Wrisberg-type discoid lateral meniscus and an incomplete-type medial discoid meniscus were confirmed. The symptomatic lateral meniscus was saucerized and sutured and only the asymptomatic medial meniscus was observed. The patient was doing well 24 months after surgery. Conclusion: We report a rare case of bilateral medial and lateral discoid menisci.

Lateral Patellar Facetectomy Reduces the Incidence of Anterior Knee Pain in Patellar Resurfaced Total Knee Arthroplasty.

Lateral patellar facet impingement (LPFI) can cause anterior knee pain (AKP) after patellar resurfaced total knee arthroplasty (TKA). Recently, lateral patellar facetectomy (LPF), which has been used for LPFI, has been performed during primary TKA, providing good clinical outcomes. However, the effect of LPF on AKP in primary patellar resurfaced TKA has not been sufficiently studied. The purpose of this study was to examine the effect of LPF on the development of AKP in patellar resurfaced TKAs with minimum follow-up of 3 years. This retrospective cohort study included 84 knees of 66 consecutive patients who underwent patellar resurfaced TKA between April 2007 and November 2014 in our hospital. The subjects were divided into two groups: TKA with LPF (LPF group; 47 knees) and TKA without LPF (no-LPF group; 37 knees). Postoperative AKP, the primary outcome, the Japanese Orthopaedic Association (JOA) score, and range of motion were investigated at the final visit and compared between the two groups. Six knees (16.2%) had AKP in the no-LPF group, whereas none of the knees had AKP in the LPF group at the final visit. The incidence of AKP was significantly lower in the LPF group (p = 0.004). The postoperative JOA score and flexion angle were significantly higher in the LPF group than in the no-LPF group. LPF correlated with less incidence of postoperative AKP and improved the JOA score and knee flexion angle. In patellar resurfaced TKA, LPF may be considered an additional maneuver to avoid postoperative AKP.

Pressurized carbon dioxide lavage reduces the incidence of a radiolucent line around the tibial component two years after total knee arthroplasty.

INTRODUCTION: In cemented total knee arthroplasty (TKA), pressurized carbon dioxide (CO2) lavage prior to cement fixation can eliminate debris at the bone-cement interface and is considered effective for increasing cement penetration and preventing aseptic loosening. Regarding the risk of a preliminary diagnosis of implant loosening, a radiolucent line (RLL) is a valuable sign. The purpose of this study was to compare the incidence of a tibial RLL at 2 years after TKA with and without pressurized CO2 lavage. METHODS: This is a retrospective study. One hundred knees from 98 patients were enrolled in this study. TKA was performed without pressurized CO2 lavage (CO2- group) for the first 47 knees, and with pressurized CO2 lavage (CO2+ group) for the next 53 knees. The depth of cement penetration was measured just after surgery, and the incidence of tibial RLL > 2 mm at 2 years after TKA was determined. RESULTS: Significant differences between groups were not seen regarding pre- and postoperative clinical factors. The depth of cement penetration in each area was significantly higher in the CO2+ group. The frequency of knees with RLL > 2 mm was significantly lower in the CO2+ group than in the CO2- group (p < 0.001). CONCLUSIONS: Pressurized CO2 lavage improved cement penetration and decreased the incidence of tibial RLL > 2 mm at 2 years after TKA.

Effects of foot progression angle on kinematics and kinetics of a cutting movement.

PURPOSE: Foot progression angle is a key factor for biomechanical knee load, which is associated with noncontact anterior cruciate ligament (ACL) injury during sports-specific tasks. The purpose of the present study was to assess the biomechanics of trunk, pelvis, and lower extremities during a cutting maneuver under different foot progression angles. METHODS: Nineteen male collegiate athletes (ages 18-24) participated in the present study. Cutting motion was analyzed using eight infrared cameras (250 Hz), two force plates (1250 Hz), and 44 reflective markers. Subjects performed 45-degree side cutting maneuvers under three foot progression angles, including 20 degrees (toe-out: TO), 0 degrees (neutral: TN), and - 20 degrees (toe-in: TI). Peak values of each biomechanical parameters in trunk, pelvis, hip, and knee within a first 40% stance phase and each parameter at the timing of the peak vertical ground reaction force were assessed. A statistical analysis was performed to compare data among the three-foot progression angles using the Friedman test. RESULTS: Peak angles of knee abduction, tibial internal rotation, hip internal rotation, and hip adduction were significantly greater for TI position than for TO position (p < 0.01). Peak moments of knee abduction and tibial internal rotation under TI position were also significantly larger than TO position (p < 0.01). Moreover, greater peak pelvis-trunk rotation was found for TI position than for TN and TO positions (p < 0.01). CONCLUSION: From the present study, TI position could lead to an increased risk of ACL injury during a pre-planned cut maneuver, compared to TO position.

Optimal time period for blood glucose level evaluation after total knee arthroplasty in patients without diabetes: a prospective, observational study.

BACKGROUND: Postoperative hyperglycemia has been reported to be a risk factor for postoperative infection even in patients without diabetes mellitus (DM). However, there is no standard for how long blood glucose level (BGL) monitoring should be performed after total knee arthroplasty (TKA). The purpose of this study was to determine the optimal time period for BGL evaluation after TKA in patients without DM. METHODS: This prospective study included 132 knees of 110 patients who underwent TKA between March 2018 and July 2021 in our hospital. Fasting BGLs were measured preoperatively, at 9:00 PM on the day of surgery (DOS), and at 7:00 AM on postoperative days (PODs) 1, 2, and 3. Patients were divided into two groups with a preoperative hemoglobin A1c (HbA1c) cut-off value of 5.9%, and the BGLs on POD 1 were compared between the two groups. RESULTS: The BGLs were significantly higher on the DOS, POD 1, and POD 2 than preoperative levels. The BGL was significantly higher on POD 1 than at any other time point. Patients with an HbA1c ≥ 5.9% had significantly higher BGLs than those with an HbA1c < 5.9% on POD 1. CONCLUSIONS: The optimal time period for BGL evaluation after TKA in patients without DM was considered to be from postoperative to POD 2. Patients with an HbA1c ≥ 5.9% may require careful perioperative glycemic control.

Association between magnetic resonance imaging characteristics and pathological findings in entire posterior cruciate ligament with mucoid degeneration.

Magnetic resonance imaging (MRI) findings of a tram-track appearance and celery stalk appearance in mucoid degeneration of the cruciate ligament are valuable; however, their pathological basis is unclear. Because these appearances are generally seen throughout the entire ligament, the association between MRI findings and pathological findings must be verified in specimens of the whole degenerated ligament, including the ligamentous attachments to bone. We herein report two cases of mucoid degeneration of the posterior cruciate ligament with osteoarthritis of the knee requiring total knee arthroplasty. The entire degenerated ligament, including the ligamentous attachments to bone, was removed and pathologically evaluated. On pathological examination, the central portion of the lesion showed typical mucoid degeneration, whereas the marginal and adherent portions showed normal ligament tissue, consistent with a tram-track appearance on T2-weighted MRI. The fibrous normal ligament tissues in the longitudinal direction in regions of mucoid degeneration were consistent with a celery stalk appearance on T2-weighted MRI. No mucoid degeneration was found in the attachment area. The tram-track appearance and celery stalk appearance of mucoid degeneration on MRI can be explained by the pathological findings.

Vitamin A intake is related to stress fracture occurrence in male collegiate long-distance runners.

BACKGROUND: Nutrient intake has an essential role in bone disorder prevention among long-distance runners. However, the influence of Vitamin A intake on the risk of stress fractures remains unknown. This prospective study aimed to investigate the association between Vitamin A intake, and stress fracture occurrence in male collegiate long-distance runners. METHODS: Forty-one male long-distance runners were recruited from a top-class long-distance college running team whose complete survey data on bone mass, anthropometric measurements, blood and urine tests, food intake frequency, history of competing in long-distance races, and monthly running distance during 2009-2010 were available. The influence of factors related to stress fractures, including Vitamin A intake, at baseline and the occurrence of stress fractures during the 1-year period were investigated. RESULTS: Four athletes experienced stress fractures during the study period (stress fracture group) and had significantly higher Vitamin A, calcium, and iron intake at baseline compared with that in the nonstress fracture group. In the stress fracture group, the mean daily Vitamin A intake was 2792 µg of retinol activity equivalents (RAE), which was higher than the upper intake limit for males aged 18-25 years in the Japanese Dietary Standard. Logistic regression analyses showed that only Vitamin A intake independently contributed to stress fracture occurrence. The odds ratio of developing stress fractures with a 100-µg RAE increase in Vitamin A intake was 1.22. CONCLUSIONS: A result of the present study suggested that Vitamin A intake was associated with stress fracture occurrence in male collegiate long-distance runners.

Suture Anchor Repair With Fully Threaded Knotless Anchors for Quadriceps Tendon Rupture Resulted in Favorable Outcomes After 2 Years.

PURPOSE: To investigate clinical outcomes over 2 years in cases of quadriceps tendon rupture (QTR) that were surgically treated using fully threaded knotless anchors. METHODS: A total of four knees in four male patients with QTR repaired with fully threaded knotless anchors at our hospital from November 2017 to January 2019 were enrolled. Mean patient age at surgery was 65.3 years (range: 61-70 years). Intraoperatively, stability of the sutured site was confirmed by knee flexion to 90°. Full weight walking with the orthosis in extension was commenced on the seventh postoperative day. Surgical findings, pathologies of the ruptured quadriceps tendons, and postoperative clinical outcomes were evaluated in all patients. RESULTS: The QTR was complete in three cases and partial in one. Average surgical duration was 58.5 (range: 49-74) minutes. Pathological evaluation revealed hyaline degeneration with granulation of the quadriceps tendon in two cases. No complications, such as infection and rerupture, occurred. Magnetic resonance imaging performed 1 year postoperatively confirmed complete healing of the repaired tendon. The mean follow-up period was 35.5 months (range: 24-46 months). None of the patients had extension lag of the knee, and mean Lysholm score and range of flexion were 95.3 (range: 85-100) and 141.3° (range: 140-145°), respectively, at the final follow-up. CONCLUSIONS: Clinical outcomes were favorable in all cases, including two cases with pathological degenerative changes. Suture anchor repair with fully threaded knotless anchors can be considered a minimally invasive and effective method for QTR, with sufficient strength to allow early rehabilitation.

Not Using a Tourniquet May Reduce the Incidence of Asymptomatic Deep Venous Thrombosis After ACL Reconstruction: An Observational Study.

BACKGROUND: Deep venous thrombosis (DVT) and pulmonary embolism are serious potential complications after anterior cruciate ligament reconstruction (ACLR). Little is known about the influence of tourniquet use on the incidence of DVT after ACLR. PURPOSE: To compare the incidence of DVT after ACLR with and without the use of a tourniquet. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Between November 2018 and May 2020, a total of 60 consecutive ACLRs in 60 patients, including 7 revision surgeries, were performed without tourniquet use at our hospital and were enrolled in this study (T- group). In addition, 55 consecutive ACLRs in 55 patients, including 10 revision surgeries, were performed with tourniquet use between April 2017 and September 2018 and were enrolled as the control group (T+ group). DVT was diagnosed using ultrasonography of both legs performed preoperatively and at postoperative week 1. The incidence of postoperative DVT was compared between the T- and T+ groups. Logistic regression analysis was performed to evaluate the effect of older age (≥40 vs <40 years) and tourniquet use on the occurrence of DVT. RESULTS: No DVTs were detected preoperatively. The incidence of postoperative DVT was significantly lower in the T- group compared with the T+ group (1 patient [1.7%] vs 9 patients [16.4%]; P = .005). All patients with DVT were asymptomatic. Although the mean operative time was not significantly different (80.8 minutes in the T+ group vs 78.5 minutes in the T- group; P = .461), the mean blood loss from the drain was significantly lower in the T- group than in the T+ group (149.9 vs 201.9 mL; P < .001). Age ≥40 years and tourniquet use were significantly related to the occurrence of DVT (odds ratio, 8.3 [95% CI, 1.9-36.8]; P = .005; and odds ratio, 8.8 [95% CI, 1.0-75.3]; P = .047, respectively). CONCLUSION: ACLRs performed without tourniquet resulted in a significantly lower incidence of DVT after ACLR and significantly less bleeding from drains. If adequate visibility of the surgical field is obtained, ACLR without tourniquet use may reduce the incidence of DVT.

The "coiling-up procedure": a novel technique for extra-articular arthroscopy.

The "coiling-up procedure" is a novel technique for extra-articular arthroscopy. A coil-shaped lifter is used to create the extra-articular working space, and a dry arthroscopy is performed. It can be combined with conventional intra-articular arthroscopy to enable direct vision from both inside and outside the joint. We have successfully used this technique to perform a vastus lateralis release in cases of painful bipartite patella. This is an innovative technique that offers the possibility of expanding the indications for extra-articular arthroscopy to other areas of the body. We describe in detail the technique for this new procedure in the knee.

Medial patellofemoral ligament reconstruction with hanger lifting procedure.

Medial patellofemoral ligament (MPFL) reconstruction has become a common surgical procedure in the treatment of recurrent dislocation of the patella. A technique of MPFL reconstruction with the "hanger lifting procedure" using extra-articular arthroscopy is presented. After conventional intra-articular arthroscopy, an incision about 1 cm long is made at the superomedial edge of the patella. A bone tunnel is created with a guide pin and overdrilling method, from this portal to the subcutaneous surface of the patella. Using a semi-loop-shaped hanger, the harvested Gracillis tendon is passed through the bone tunnel using a passing pin. Under extra-articular arthroscopy with the "hanger lifting procedure", this tendon is then led back to the superomedial portal. Both ends of the Gracillis tendon are then led to the femoral fixation site posterosuperior to the medial epicondyle with a tendon passer, and fixed by an absorbable interference screw. This procedure can be performed under a minimum incision using a hanger, but control radiographs should be taken to confirm appropriate placement of bone tunnels.

Accuracy of implant positioning for minimally invasive total knee arthroplasty in patients with severe varus deformity.

Minimally invasive surgery (MIS) in total knee arthroplasty (TKA) reportedly yields decreased patient morbidity and a rapid return of function, but how much deformity can be accepted for MIS-TKA remains unclear. This study investigated 238 knees from 218 consecutive patients who underwent MIS-TKA. Patients were divided into groups with tibiofemoral mechanical axis (TFM) 195 degrees or greater and TFM less than 195 degrees, then clinical and radiographic results were compared. Similar improvements in knee score at 3 months postoperatively were obtained in the both groups, whereas radiographic accuracy of the coronal alignment in the TFM >or=195 degrees group was inferior to that in TFM <195 degrees group. Postoperative TFM was significantly worsened in patients with lateral bowing angle of the femoral shaft (LBFS) 4 degrees or greater, and 53% of patients in the TFM >or=195 degrees group displayed LBFS 4 degrees or greater, explaining the inferior radiographic accuracy in this group compared with the TFM <195 degrees group. These results indicate that use of MIS techniques decreases radiographic accuracy, particularly in patients with severe genu varum and increased LBFS.

Extension limitation in standing affects weight-bearing asymmetry after unilateral total knee arthroplasty.

The aim of this study was to evaluate weight-bearing condition after unilateral total knee arthroplasty (TKA) during standing and to examine whether the condition affects knee kinetics during gait in both limbs. Twenty-five patients, who underwent unilateral TKA for symptomatic bilateral osteoarthritis and who were on average 74 years old, participated. As a result, operated limbs became dominant in 80% of the patients. The other 20%, who had lack of knee extension during standing, showed more weight bearing in nonoperated knees. Furthermore, extension limitation in the operated knee in standing led to mechanical overload in the contralateral limb during gait. Therefore, to avoid progression of the osteoarthritis in the contralateral knee, it is important to acquire full extension in the operated knees during standing after unilateral TKA.

Benign Neglect of Anomalous Insertion of the Anterior Horn of the Medial Meniscus as an Incidental Finding During Knee Arthroscopy.

PURPOSE: To evaluate the clinical results following arthroscopic surgery in patients with anomaly of the anterior horn of the medial meniscus (AHMM) that was found unexpectedly during surgery and discuss whether resection is necessary in patients without anteromedial knee pain (AMKP). METHODS: Between May 2014 and April 2017, a total of 387 knee arthroscopies in 379 patients were performed. Among these, 11 knees in 11 patients showed an anomalous insertion of the AHMM (incidence, 2.8%), and all 11 patients were included in this study. For these 11 patients, medical records including preoperative diagnosis, arthroscopic findings, and pre- and postoperative clinical evaluations were analyzed. RESULTS: None of the patients complained of AMKP before arthroscopy. Two patients were diagnosed with lateral meniscus injury and the other 9 patients were diagnosed with medial meniscus injury. All anomalies of the AHMM were found incidentally during arthroscopic surgery. The anomaly formed a band-like structure arising from the anterior portion of the medial meniscus and was attached to the anterior aspect of the ACL and femoral intercondylar notch. All 11 patients underwent partial meniscectomy, but anomalies of the AHMM were not resected. One patient was excluded from clinical evaluation, as that patient required subsequent total knee arthroplasty due to osteoarthritis. For the other 10 patients, mean follow-up was 36.8 months (range, 26-61 months). Knee pain was relieved, and none developed postoperative AMKP. Mean Lysholm score improved significantly from 55.9 to 91.2 (P < .001). CONCLUSIONS: The incidence of the anomaly was 2.8% in our study. If the patient has no AMKP before arthroscopic surgery, anomaly of the AHMM is a silent lesion that does not warrant resection. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

When does postoperative standing function after total knee arthroplasty improve beyond preoperative level of function?

The purpose of the current study was to investigate inpatient recovery process during relaxed standing, and to clarify the question of when postoperative standing function would improve beyond preoperative level of function following total knee arthroplasty (TKA). Thirty patients with bilateral knee osteoarthritis, averaged 75 years old, participated. Subjects underwent unilateral TKA. Evaluations were divided into two categories; subjective and objective components. Subjective component was based on pain level (Visual Analog Scale: 100 mm), and objective component consisted of vertical knee force (%BW) and knee flexion angle (degrees) during relaxed standing. Data evaluations were done pre- and post-operatively. Preoperative pain score was 69.1. After TKA, pain level became maximum (89.9) and significantly larger on postoperative day 3. Thereafter, pain gradually decreased, and it (60.4) was significantly smaller on postoperative day 8 than preoperative score. Preoperative vertical knee force was 43.5%BW. After TKA, it became minimum (32.8) on postoperative day 3. Thereafter, knee force gradually increased, and it (44.1) was significantly larger on postoperative day 17. Preoperative knee flexion angle was 15.6 degrees . After TKA, knee flexion angle during standing became maximum (20.0) on postoperative day 4. Thereafter, subjects could gradually extend the knee, and on postoperative day 16, it (14.3 degrees ) was smaller. From our results, subjective pain was significantly reduced from postoperative day 8, and objective knee condition, including vertical knee force on TKA side and knee flexion angle on TKA side during standing, significantly became better from postoperative day 17 and 16, respectively.