Effect of limited range of motion of the hip joint and leg-length discrepancy on gait trajectory: an experiment to reproduce the asymmetric gait that occurs in patients with osteoarthritis of the hip joint.

PURPOSE: Although some symptoms that often occur with hip joint osteoarthritis (OA) may be involved in the appearance of gait disturbance, the main cause has not been identified. We hypothesised that the abnormalities in gait trajectory of patients with hip joint OA are mainly caused by limited range of motion of the hip joint or the presence of leg-length discrepancy, or both. To investigate this hypothesis, we examined whether the abnormal gait trajectory in patients with hip joint OA can be reproduced in healthy individuals by asking them to wear a hip orthosis and shoe orthotic (insole). METHODS: We recruited 2 groups of participants: patients with hip joint OA (OA group, 38 patients) and healthy individuals who imitated patients with OA of the hip joint by wearing a hip orthosis or shoe orthotic (10-mm or 20-mm insole) or both (simulated OA group, 6 individuals). For gait analysis, we used a portable, wearable gait analyser with inertial sensors to evaluate 3-dimensional (3D) changes in gait trajectory. RESULTS: In the OA group, the patterns of gait trajectories that were drawn on the 3 planes (coronal, sagittal, and horizontal planes) could be roughly divided into 3 types. The gait trajectories that were drawn when wearing a hip orthosis in the simulated OA group were very similar to 1 of the 3 patterns of gait trajectory that occurs in the OA group. CONCLUSIONS: We were able to reproduce the abnormal gait trajectory that is observed in ⅓ of patients with hip OA in healthy individuals, so we propose that an extreme reduction in hip joint ROM is 1 of the causes of abnormal gait pattern in patients with OA of the hip joint. A difference in leg length of 20 mm alone has little effect on gait trajectory.

Comparison of anemia, renal function, and nutritional status in older women with femoral neck fracture and older women with osteoarthritis of the hip joint.

BACKGROUND: Several studies in older patients with femoral neck fracture found that preoperative anemia and malnutrition were associated with higher mortality and poorer physical function. Therefore, we compared nutritional status, Hb level, and renal function in women with femoral neck fracture and women of the same age with osteoarthritis of the hip joint. METHODS: We enrolled 257 women aged 70 years and older who suffered femoral neck fracture (F group) or who were scheduled to undergo total hip arthroplasty for osteoarthritis of the hip joint (OA group). The F and OA groups were further divided into 2 groups on the basis of age, ie, 74 years old and younger (F70 and OA70) and 75 years old and older (F75 and OA75). To assess whether patients had undernutrition, mortality risk, anemia, and renal dysfunction, we assessed Geriatric Nutritional Risk Index (GNRI), Hb, and eGFR. RESULTS: We found a significant difference in the mean Hb levels and GNRI scores between the F75 and OA75 and F70 and OA70. Moreover, we found a moderate correlation between Hb level and GNRI score in the F75 and OA75. With respect to the GNRI category, the percentage of patients at moderate or major risk was 42.1% in the F70 group and 57.6% in the F75 group but only 1.9% in the OA70 group and 4.3% in the OA75 group. CONCLUSION: We found that women with femoral neck fracture had significantly lower Hb levels and lower GNRI scores than women with hip OA in the same age and that anemia and undernutrition were closely linked in women aged 75 and above. Moreover, we found that more than 40% of patients with a femoral neck fracture had a moderate to major risk on the basis of their GNRI scores.

Effects of social isolation associated with the COVID-19 pandemic on hip muscle strength, hip joint pain, and walking ability in patients with osteoarthritis of the hip joint.

To reduce the spread of the Sars-CoV-2 virus, governments in many countries adopted a social isolation strategy. However, social isolation may adversely affect people's health, e.g., by decreasing the muscle function of lower limbs. We recruited 118 patients who had undergone total hip arthroplasty (THA) and 87 patients with moderate to severe hip joint osteoarthritis (OA) and measured hip muscle strength, hip joint pain, and walking ability from before to one year after the start of the COVID-19 pandemic. During the pandemic, hip flexion (straight leg raise, SLR) strength decreased in 13.1% of patients in the post-THA group and 25.6% in the severe-OA group; in the severe-OA group, the decrease in SLR strength was mainly in patients aged 65 years and older. In addition, pain increased to mild or moderate and walkable distance decreased in more patients in the severe-OA group.

Comparison of the 5-Year Outcomes Between Standard and Short Fit-and-Fill Stems in Japanese Populations.

Background: Fit-and-fill stems are known to have excellent outcomes; however, severe stress shielding has been reported in Japanese populations. Short fit-and-fill stems were modified for Asians; however, there have been no previous reports of its outcome. In this study, we compared the 5-year (mean 68-month) outcomes of 2 fit-and-fill stems with different lengths (standard or short). Material and methods: We reviewed 100 total hip arthroplasties in each standard- or short-stem group. Radiographs were evaluated for femoral morphology, stress shielding, bone remodeling, and fixation. Clinical evaluation was performed using the Japanese Orthopaedic Association (JOA) scores. Results: There was no difference in the degree of stress shielding between the 2 groups. Significant differences were observed in radiolucent lines in zone 4 (P = .005) and cortical hypertrophy in zone 3 (P < .0001) and 5 (P = .048) between the 2 groups. The canal flare index (P < .0003), cortical index (P < .0003), height (P < .0345), and stem size (P < .0081) individually affected stress shielding in the standard-stem group. In contrast, the cortical index (P < .0107) was the only relative factor in the short-stem group. All stems were judged to have bone ingrowth. The JOA score improved significantly (P < .0001); however, there were no significant differences between the 2 groups. Conclusion: The outcomes of both standard and short fit-and-fill stems were favorable. There were no significant differences in the stress shielding or JOA scores. Although there were a few differences in bone remodeling and factors affecting stress shielding, stem length reduction has been achieved without adverse effects with the Japanese femur.

Acetabular cartilage abnormalities in elderly patients with femoral neck fractures.

INTRODUCTION: Both hemiarthroplasty (HA) and total hip arthroplasty (THA) are widely accepted surgical procedures for hip replacement following displaced femoral neck fractures. However, in cases involving an intact joint line before surgery, the choice between HA and THA remains debatable. This study investigated the prevalence of acetabular cartilage and labral abnormalities in elderly patients with femoral neck fractures. METHODS: Thirty-seven patients underwent hip arthroplasty for femoral neck fractures between April 2020 and February 2021. After excluding 4 patients, 33 patients (6 men and 27 women; mean age = 82.2 [range = 67-98] years) with fractures in 12 left and 21 right hips were included. After femoral head removal during arthroplasty, the acetabulum was macroscopically examined for the presence of cartilage and labral lesions. Acetabular cartilage abnormalities were classified as either overall degeneration or partial damage according to the cartilage damage classification system. RESULTS: Acetabular cartilage abnormalities, including overall degeneration or partial damage, were found in all hips (100%). Out of the 33 hips, overall degeneration, partial damage, and labral abnormalities were detected in 32 (96.9%), 16 (48.4%), and 9 (27.2%) hips, respectively. DISCUSSION: In this study, most elderly patients with femoral neck fractures exhibited acetabular cartilage and labral abnormalities, which were already present at the time of surgery. Therefore, surgeons should carefully examine these abnormalities as they may impact postoperative outcomes such as pain and function.

Effects of Pre-Donated Autologous Blood Transfusion on Peri-Operative Hemoglobin Concentration and Mid-Term Health Outcomes in Primary Total Knee Arthroplasty.

The effects of auto-BT in primary TKA on the perioperative hemoglobin (Hb) concentration and mid-term health outcomes are unknown. This study was performed to analyze the detailed changes in the perioperative Hb concentration before and after the operation (days 0-14 postoperatively), cardiovascular events, and mortality rate within 1 and 5 years postoperatively. One hundred patients undergoing primary TKA with auto-BT using 800 mL of preoperatively collected blood at the authors' institution were included. The mean Hb concentration before and after autologous blood collection was 12.7 ± 1.1 and 11.7 ± 1.2 g/dL, respectively. After primary TKA with auto-BT, the mean Hb concentration on day 0, 1, 3, 7, and 14 was 10.2 ± 1.2, 9.9 ± 1.2, 10.4 ± 1.3, 10.5 ± 1.3, and 11.0 ± 1.3 g/dL, respectively. Only one (1%) patient required additional allogenic blood transfusion. No patients developed cardiovascular events, and the 1- and 5-year postoperative mortality rate was 1.0% and 2.0%, respectively. Primary TKA with auto-BT showed relatively small perioperative changes in the Hb concentration, a low incidence of cardiovascular events, and a low mortality rate within 1 and 5 years postoperatively. These findings suggest that auto-BT, in which blood is preoperatively collected, is beneficial for patient safety and health, even if its cost-effectiveness may be debatable.

Changes in serum creatine kinase and C-reactive protein after posterior and direct anterior approaches in total hip arthroplasty.

PURPOSE: Some studies reported that measuring serum creatine kinase (CK) level is an objective method with which to determine the relative invasiveness of surgery. The purpose of this study was to evaluate the change in postoperative serum CK levels as a measure of whether the direct anterior approach (DAA) is less invasive than the posterior approach (PA) regarding postoperative rehabilitation. MATERIALS AND METHODS: We prospectively recruited 71 women who were undergoing total hip arthroplasty, 47 were treated by the PA and 24 by the DAA. Serum CK and C-reactive protein (CRP) levels were measured preoperatively and 3 hours and 1, 4, 7, 10, and 14 days after the operation. RESULTS: The serum CK levels were significantly higher in the DAA group than in the PA group on postoperative days 1, 4, 7, 10, and 14. On postoperative day 4 and 7, the percentage of patients whose serum CK levels were above the normal range was 46.8% and 8.5% in the PA group and 95.2% and 45.5% in the DAA group. CONCLUSIONS: CK levels were significantly higher in the 2 weeks after THA by a DAA than after the same procedure by a PA indicating that DAA causes prolonged muscle damage. Although the DAA is considered to be a muscle-sparing approach this may not be the case and DAA may not actually be a minimally-invasive approach.

Appearance and Frequency of Deep Venous Thrombosis After Total Hip Arthroplasty.

Objectives: Postoperative venous thromboembolism is an important peri-operative complication associated with total hip arthroplasty (THA). In particular, early detection of deep venous thrombosis (DVT) is important for the prevention of pulmonary embolism (PE). However, the methods and timing of examinations for DVT detection differ among the facilities. This study aimed to clarify the time, site, and frequency of DVT after THA. Materials and Methods: Background characteristics including age, sex, body mass index, diagnosis, operation type, operation time, and anesthesia type were investigated in 348 patients who underwent THA at our hospital between April 2017 and April 2019. Blood tests were performed preoperatively and on postoperative days (POD) 0, 1, 3, 7, 14, and 21. Simultaneously, vascular ultrasonography was performed to investigate the time and site of thrombus occurrence before and after the surgery. Results: DVT was observed in 27.2% of the patients on POD 21. The DVT-positive ratio was 9.4% (6/64) in males and 31.3% (89/284) in females. There was a significant difference between the groups (p = 0.0002). Patients in the DVT-positive group were significantly older than those in the DVT-negative group (73.0 ± 7.9 years vs. 63.3 ± 11.2 years, p = 0.0041). DVT mainly occurred in the soleal vein (74.7%). However, there was no significant difference between the operated and non-operated sides. In the DVT-positive group, thrombus occurred in 13.3% of preoperative cases, 20.0% on POD 0, 46.7% on POD 1, 13.3% on POD 3, 6.7% on POD 7, and 0% on POD 14 and 21. Conclusions: Vascular ultrasonography showed that thrombus occurred most frequently in the soleal vein. Thrombus occurred in 66.6% of DVT-positive patients by POD 1, indicating that thrombus appeared very early after surgery. All thrombus cases were formed by POD 7.

New Linked-Wire-Type External Fixator (the Ichi-Fixator System) for Metacarpal Fractures: Case Series and Literature Review.

Background: External fixator is an effective treatment option in the comminuted or unstable metacarpal fractures. The new linked-wire type of external fixator (the Ichi-Fixator System) developed for hand and wrist fractures enables fine adjustment of the fixation under fluoroscopic inspection through small screws inside the fixator fitted externally. This technique is designed to reinforce the stability and rigidity of conventional percutaneous Kirchner wire fixation. The aim of this study is to assess the effectiveness of the fixator for comminuted or unstable metacarpal fractures through the evaluation of short-term results in ten cases. Methods: Patients were fixated with fixator pins and metal clamps using the Ichi-Fixator System. All patients were then examined for post-operative complications, functional recovery, visual analogue scale (VAS) score, and the Quick Disabilities of the Arm, Shoulder, and Hand (Q-DASH) score at the end of the final follow-up consultation. Results: Operative treatment using the Ichi-Fixator System facilitates anatomical reduction and allows immediate full mobilization, producing good outcomes. No infections were observed in all cases, including those at pin insertion sites. There were no implant failure and nonunion. Patients could perform all routine activities with normal grip strength and retained a full range of hand motion without pain. This treatment method with improved postoperative comfort would allow immediate return to work, which would clearly boost patient satisfaction. Conclusions: Ichi-Fixator System is considered to be useful for the treatment of metacarpal fractures, and this will provide a new surgical option for all hand fractures.

Radiographic assessment of the tibiofemoral relationship in anterior cruciate ligament deficient knees.

BACKGROUND: The intercondylar roof line is one of the indicators used during anterior cruciate ligament (ACL) reconstruction to see the relation to the position of the tibial tunnel. The tibial tunnel can be made posteriorly in the anteriorly subluxated tibia. During ACL reconstruction, the tibiofemoral relationship of the opposite or normal knee should be considered. The purpose of this study was to examine the radiographic tibiofemoral relationship of the sagittal plane in a standing position in ACL deficient knees. METHODS: In this study, 64 patients were evaluated for inclusion. Lateral radiographs of the injured and uninjured knee were obtained preoperatively in a standing position. The knee was fully extended with the opposite foot on a step, asking the patients to bear weight fully on one leg. The tibiofemoral relationship was evaluated in the radiographs. RESULTS: The mean value of anterior tibial subluxation was 1.2 mm in the injured side and -1.6 mm in the uninjured side. The tibia was located in a significantly anterior position in the injured knee (p < 0.0001). The mean distance of the space for the ACL was 9.7 mm in the injured side and 10.7 mm in the uninjured side (p < 0.01). Roof-plateau angle averaged 63.6° in the injured side and 67.4° in the uninjured side (p < 0.001). CONCLUSION: The tibiofemoral relationship of the ACL deficient knee was different from that of normal knee in the standing position. The relationship of the normal knee should be considered during ACL reconstruction and the risk of secondary lesions in the ACL deficient knee in activities of daily life should be considered.

Association of ABO blood group with postoperative total bleeding volume in patients undergoing total hip arthroplasty.

BACKGROUND AND OBJECTIVES: As individuals with blood types A, B and AB have approximately 25% higher levels of vWF than those with type O, the risk of developing venous thrombotic events has been investigated in a number of clinical studies, but whether individuals with type O blood experience increased bleeding remains to be clarified. The purpose of this study was to evaluate an association of ABO blood group with intraoperative bleeding and postoperative total bleeding in patients undergoing total hip arthroplasty. MATERIALS AND METHODS: We prospectively recruited 84 women who were undergoing total hip arthroplasty. The differences between blood groups in mean age, body weight, preoperative and postoperative Hct levels, and postoperative/preoperative Hct ratio, intraoperative bleeding volume (IBV), and total bleeding volume (TBV) were evaluated. RESULTS: Twenty-six patients had type A blood, 17 had type B, 9 had type AB, and 30 had type O. There were no significant differences in mean age, body weight or operating time between the different ABO blood groups. While there was no significant difference in these Hct levels or IBV among the different blood groups, there was a significant difference in TBV between type O and type AB, and between type O and non-type O. CONCLUSION: Our study in patients undergoing total hip arthroplasty suggests that patients in blood group O tend to have large amounts of bleeding.

Total hip arthroplasty with reconstruction of acetabulum through direct anterior approach for metastatic bone disease of acetabulum combined with pathological proximal femoral neck fracture: A case report.

Most surgical treatment options for metastatic acetabular lesions involve variants of total hip arthroplasty (THA). However, these are technically complex reconstructions performed in very frail patients, and previous reports indicate complications such as dislocation, deep infection, aseptic loosening, and intraoperative death. A 73-year-old man presented to the emergency department at our hospital with right hip pain following a fall. He had undergone nephrectomy for the treatment of right kidney cancer at the age of 68 years. Four years after the nephrectomy, multiple lung metastases, pelvic bone metastases, and right femoral head and neck bone metastases were found. A radiograph of the hip joint showed a pathological proximal femoral fracture with a radiolucent lesion of the acetabulum. THA with acetabular reconstruction using a Kerboull-type (KT) plate through the direct anterior approach (DAA) was performed. After removal of the femoral head, curettage of the metastatic acetabular dome lesion was carefully performed under fluoroscopic guidance. After the KT plate was placed, cementation of the metastatic acetabular dome lesion was performed, and an optimally sized polyethylene liner was fixed with cement. A cemented stem was inserted after confirming the hip joint stability. At the 14-month follow-up, he could walk steadily without any complications and his modified Harris hip score was 100. The DAA conserves soft tissue because it is an intermuscular approach. Accordingly, postoperative recovery is fast and thus associated with a low dislocation rate and effective pain reduction. The acetabulum with metastatic disease was reconstructed using a KT plate for hip joint stability. Bone with metastatic disease that appears adequate at the time of THA may become incompetent after a few years. THA with acetabular reconstruction using a KT plate through the DAA was an effective treatment for metastatic bone disease of the acetabulum combined with pathological proximal femoral neck fracture.

Effect of femoral offset and limb length discrepancy on hip joint muscle strength and gait trajectory after total hip arthroplasty.

BACKGROUD: Femoral offset (FO) and limb length discrepancy (LLD) are important perioperative considerations when performing THA. Decreased FO prevents improvement of gait and muscle recovery and residual LLD has a prominent influence on patient satisfaction with THA, while few studies have investigated the relationship between FO and/or LLD and gait disturbances. We investigated the association between these two factors and hip muscle strength and the results of 3-D gait analysis after THA. METHODS: We evaluated 92 patients (including 20 patients who underwent gait analysis) in whom total hip arthroplasty was performed for unilateral evere osteoarthritis of the hip joint. FO and LLD were measured on a standard anteroposterior radiograph of the pelvis. Hip muscle strength was evaluated by isometric hip flexion (in the manner of straight leg raising test: SLR) and hip abduction strength. To evaluate 3-D walking trajectory, we used a portable gait analyzer. RESULTS: Reduction of global FO by > 5 mm after THA compared to the contralateral hip was associated with hip abductor muscle weakness. On the other hand, LLD ≤ 20 mm had no influence on hip abductor muscle strength and SLR strength. In gait analysis, SLR strength showed a significant difference between the sagittal plane symmetrical and asymmetrical groups. CONCLUSION: Postoperative global FO > 5 mm less than that of the contralateral hip was associated with hip abductor muscle weakness. And, from the results of 3-D gait analysis, SLR weakness may increase gait asymmetry in the sagittal plane.

Physiologic Leg Bowing is not a Physiologic Condition but Instead is Associated with Vitamin D Disorders in Toddlers.

When children around 2-year-old show leg bowing without lower-limb radiographic abnormalities for rickets, the leg bowing is classified as "physiologic" genu varum without conducting a blood test. However, it has recently been suggested that toddlers who are diagnosed with physiologic genu varum may in fact have some form of bone metabolic disorder. In this 1:2 case-control study, blood samples were obtained from 33 toddlers with genu varum without radiographic abnormalities for rickets and 66 age- and gender-matched healthy children. Serum alkaline phosphatase (sALP), intact parathyroid hormone (siPTH), 25-hydroxy vitamin D [s25(OH)D], calcium (sCa), and inorganic phosphate (sP) were measured. s25(OH)D of the subjects with genu varum (24.8 ng/ml) were significantly lower than those of the control (33.6 ng/ml) (p < 0.001). The frequency of vitamin D insufficiency/deficiency (< 20 ng/ml) of the subjects with genu varum (39%) was significantly higher than that in the control (14%) (p = 0.004) (odds ratio by vitamin D insufficiency/deficiency: 4.1 [1.5-11.1, p = 0.004]). sCa in subjects with genu varum (10.2 ng/ml) were significantly higher than in control (9.8 ng/ml) (p < 0.001), as were sALP (1057 IU/l) and siPTH (28.4 pg/ml) (740 IU/l and 8.8 pg/ml in control, respectively; p < 0.001). siPTH levels were associated with s25(OH)D levels in subjects with genu varum (r = - 0.57, p < 0.001), while no association was observed in the control (r = 0.11, p = 0.36). Genu varum without radiographic abnormalities of rickets was associated with both vitamin D and bone-metabolic disorders in toddlers, indicating that physiologic genu varum is not a physiologic condition in toddlers.

Optimal cutoff score for patient-reported outcome measures after anterior cruciate ligament reconstruction using load-displacement curve analysis.

To assess psychological components after anterior cruciate ligament (ACL) injury, we developed a new patient-reported outcome measure, the Japanese anterior cruciate ligament injury questionnaire 25 (JACL-25), and demonstrated that the JACL-25 is valid, reliable, and sufficiently responsive to evaluate psychological factors that are associated with outcomes in individuals with ACL injuries. The purpose of this study was to identify the optimum cutoff score for the JACL-25 that indicates successful clinical outcomes, combining with the graphical data obtained using the KT-2000. We studied 30 patients who underwent primary ACL reconstruction with a patella tendon or hamstring tendon autograft. On the same day of the JACL-25 evaluation, anterior knee laxity tests were performed using the KT-2000 arthrometer. ACL stiffness was calculated on the graphs of the hysteresis, which can be used to measure side-to-side differences in anterior translation. Akaike's information criterion (AIC) was used to determine the most appropriate cutoff level for the JACL-25 score for the stiffness reduction ratio and anterior-posterior (AP) translation. The average JACL-25 score was 23.8 (standard deviation (SD) 18.4). The average side-to-side displacement difference in AP translation was 2.4 (SD 4.2) mm. The average stiffness reduction ratio was 24.4% (SD 31.8). The smallest AIC values for the cutoff level for the JACL-25 score, the stiffness reduction ratio, and side-to-side differences of the anterior translation were 9, 27%, and 1.1 mm, respectively. We determined the optimal cutoff score for the JACL-25 that identifies successful clinical outcomes.

Influence of hip joint dysfunction on motor disorders in Japanese patients with osteoarthritis of the hip: Assessment of the JHEQ and GLFS-25 scores and hip muscle strength.

BACKGROUND: Motor disorders are caused by orthopedic problems that are mainly related to aging. These disorders can lead to a decline of physical activity and impairment of ADL. When evaluating a patient's motor function after treatment, it is necessary to determine whether or not the level of function is age-appropriate. To investigate the influence of hip joint dysfunction on motor disorders, we determined the JHEQ and GLFS-25 scores and performed muscle strength testing in female patients with hip osteoarthritis. METHODS: The subjects were 108 women who had received THA, 56 women scheduled for THA, and 64 women on conservative treatment. The JHEQ score (evaluation scale for hip joint function) and GLFS-25 score (evaluation scale for ADL) were determined and muscle strength testing was conducted at a routine outpatient visit. RESULTS: A strong correlation was found between the total JHEQ score and the GLFS-25 score (r = - 0.837). Patients after THA and patients with successful conservative treatment aged 60-79 years showed similar motor function to healthy persons of the same age. There was a significant difference of straight leg raising and abduction strength (both p < 0.01) between patients in GLFS-25 levels 1-3 and patients in GLFS-25 levels 4-7. CONCLUSION: While hip joint dysfunction has a strong influence on overall motor function, the patients after THA and patients with successful conservative treatment showed similar motor function to healthy persons of the same age. And patients with hip osteoarthritis must preserve or increase SLR strength to maintain adequate motor function.

Postoperative hemoglobin and recovery of hip muscle strength after total hip arthroplasty.

BACKGROUND: The presence/absence of postoperative anemia are presumed to have an impact on early recovery after surgery. This study was performed to compare hip muscle strength and hemoglobin during the perioperative period in 82 patients undergoing THA. METHODS: Evaluation of presence/absence of anemia was performed by calculating the 10-day postoperative/preoperative Hb ratio. Muscle strength was investigated before and 2 months after surgery. RESULTS: Postoperative SLR strength showed a significant difference between the patients whose 10-day postoperative/preoperative Hb ratio was <85% and ≧ 85%. CONCLUSION: We need to consider perioperative strategies to minimize anemia in order to improve patient outcomes.

Early clinical evaluation of total hip arthroplasty by three-dimensional gait analysis and muscle strength testing.

BACKGROUND: As improvement of gait is an important reason for patients to undergo total hip arthroplasty (THA) and they generally tend to evaluate its success based on postoperative walking ability, objective functional evaluation of postoperative gait is important. However, the patient's normal gait before osteoarthritis is unknown and the changes that will occur postoperatively are unclear. We investigated the change in gait and hip joint muscle strength after THA by using a portable gait rhythmograph (PGR) and muscle strength measuring device. PATIENT AND METHODS: The subjects were 46 women (mean age: 65.9 years) with osteoarthritis of the hip. Gait analysis and muscle strength testing were performed before THA, as well as 3 weeks and 3 months after surgery. We measured the walking speed, step length, and gait trajectory using PGR prospectively. PGR is attached to the patient's waist and records signals at a sampling rate of 100 Hz. Isometric torque of hip flexion and abduction were measured by using a hand-held dynamometer. RESULTS: There was no improvement at 3 weeks postoperatively, but the walking speed, stride length and muscle strength were clearly showed improvement at 3 months postoperatively. The walking trajectory was not normal preoperatively, since the trajectory was not symmetrical and did not intersect in the midline or form a butterfly pattern, and abnormality of the trajectory tended to persist postoperative 3 months despite resolution of hip joint pain after surgery. CONCLUSION: Since postoperative improvement of gait is an important consideration for patients undergoing THA, it seems relevant to evaluate changes in the gait after surgery and three-dimensional analysis with a PGR may be useful for this purpose.

Changes in serum chromium levels over 12 years after Metasul metal-on-metal total hip arthroplasty.

We reported the longitudinal changes in serum chromium levels over a minimum of 7 years postoperatively in five men and 25 women with a mean age of 60.3 years after primary unilateral total hip arthroplasty with a Metasul metal-on-metal articulation. The serum chromium ion level showed little variation (0.6-1.2 µg/L) from 2 to 12 years postoperatively in 16/30 patients after unilateral primary Metasul metal-on-metal total hip arthroplasty. On the other hand, the serum chromium level stayed high or showed gradual elevation in 8/30 patients, even though they had well-fixed and well-functioning prostheses.