Minimally invasive surgery supercapsular percutaneously-assisted total hip (SuperPath) arthroplasty.

BACKGROUND AND AIM: The benefits of minimally invasive surgical techniques in total hip arthroplasty (THA) are well known, but concerns about applying SuperPATH in patients with secondary OA of acetabular dysplasia do not have been reported. We aim to evaluate whether SuperPATH is applicable to secondary OA, furthermore, to quantify the recovery of lower extremity function. METHODS: 30 patients with secondary OA admitted for THA applying SuperPATH were investigated. Clinical Japanese Orthopaedic Association (JOA) Score and radiographical evaluation were performed. Following was examined pre- and early post-operatively; pain level, blood tests, TUG and 10-M walking time for lower limb recovery. RESULTS: Preoperative radiographic measurements revealed an average Sharp angle of 46.2 ± 2.8 degrees and CE angle of 19.4 ± 7.3 degrees. 29 THAs had Crowe Type I and 1 THA had Crowe Type II. JOA score improved from 48.8 preoperatively to 91.5 at 2 months postoperatively. The perioperative pain assessment (VAS) averaged 7.0±1.5 preoperatively, 4.6±2.6 on the first postoperative day, then decreased gradually to 1.2±1.4 at 2 weeks. Blood data showed that creatine kinase, myoglobin, and CRP were significantly elevated on the day after surgery, but they normalized at 2 weeks postoperatively. Both TUG and 10M walking time showed slightly higher values at 1 week postoperatively compared to preoperatively but recovered to the same level as preoperatively at 2 weeks after surgery. CONCLUSIONS: Our data suggests that SuperPATH approach to THA for dysplastic OA was applicable to mildly dysplastic OA and achieved an early recovery of lower limb function.

Usefulness of an Accelerometer-Based Portable Navigation System for Total Knee Arthroplasty: A Multicenter Prospective Randomized Controlled Trial.

BACKGROUND: An accelerometer-based portable navigation system was recently introduced to improve prosthetic alignment during total knee arthroplasty (TKA). The purpose of this multicenter prospective randomized controlled trial (RCT) was to evaluate the effects of this accelerometer-based portable navigation system for achieving more accurate alignment during TKA in the clinical setting. METHODS: One hundred patients with primary varus osteoarthritis of the knee were enrolled in this prospective RCT conducted in 5 hospitals. A navigation system was utilized in 50 patients (navigation group), and a conventional intramedullary femoral guide and an extramedullary tibial guide were utilized in 50 patients (conventional group). At 6 months postoperatively, weight-bearing radiographs were obtained of the whole operative leg. An experienced surgeon who was blinded to the treatment assignments then measured the alignment to 1 decimal place with use of computer software. Power analysis showed that 41 knees were required in each group. RESULTS: There were no complications as a result of the use of the accelerometer-based portable navigation system. Postoperative radiographs were obtained in 45 patients from each group. There were no significant differences in sex, age, height, body weight, body mass index, preoperative femorotibial angle, and operative time between groups. The absolute differences of the femoral prosthesis (p = 0.01), tibial prosthesis (p < 0.01), and hip-knee-ankle angle (p < 0.01) from a neutral mechanical axis were less in the navigation group compared with those in the conventional group. Alignment outliers (>2° away from the neutral mechanical axis) of the tibial prosthesis and hip-knee-ankle angle were less in the navigation group (9% and 27%, respectively) compared with those in the conventional group (31% and 49%; p = 0.01 and p = 0.04, respectively). CONCLUSIONS: To our knowledge, this is the first multicenter prospective RCT to evaluate an accelerometer-based portable navigation system. An accelerometer-based portable navigation system provides more accurate prosthetic and limb alignment in the coronal plane than conventional techniques, without extended operative time or an increased rate of complications. The results of this study may help orthopaedic surgeons decide whether or not to use an accelerometer-based portable navigation system. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Analyzing the characteristics of rising from the bed in patients having undergone total hip arthroplasty immediately after surgery.

BACKGROUND: Immediately after patients undergo total hip arthroplasty (THA), they are often coached through the process of rising from the bed to prevent dislocation. However, motion analysis of this process, which can guide coaching methods, has not been conducted. The purpose of this study was to clarify whether there is a difference in hip joint angle, rise time, pain, and difficulty based on the method of rising from the bed in postoperative patients, immediately after THA. METHODS: Twenty patients who underwent THA were enrolled in this study. Seven days after surgery, 3-D motion analysis was performed while subjects rose from the bed using six different methods that include rising from the bed using either the affected or non-affected side either with or without assistance. Hip joint angle, rise time, pain, and difficulty were evaluated. RESULTS: In all six methods, the maximal hip joint angle of the affected side was in the safe range. The maximal hip adduction angle and adduction angle at maximum flexion of the affected side were significantly lower in patients who rose from the bed using their affected side than in those who rose using their non-affected side. There were no differences in maximal hip flexion angle, internal rotation angle, internal rotation angle at maximum flexion of the affected side, rise time, pain, or difficulty regardless of the direction of rising from the bed or the use of assistance. SIGNIFICANCE: Coaching patients to rise from the bed is better performed when using the most optimal method that takes into consideration the movement direction and patient's individuality.

Polyethylene Wear Associated With 26- and 32-mm Heads in Total Hip Arthroplasty: A Multicenter, Prospective Study.

BACKGROUND: Although there were many clinical studies of highly cross-linked polyethylene (XLPE) wear among different femoral head diameters, few referred to thickness of XLPE in case larger femoral heads were used because smaller sockets were frequently used for Asian population. METHODS: This prospective study included 240 hips that underwent primary total hip arthroplasty using XLPE combined with 26-mm (group S) or 32-mm (group L) cobalt-chromium head with maximum follow-up of 10 years. We measured 3-dimensional (3-D) linear penetration rate of XLPE among same implant design groups except head diameter and estimated the validity of thinner XLPE. RESULTS: Our study demonstrated comparable 3-D linear penetration rates, which were 0.06 ± 0.07 mm/y for group S and 0.03 ± 0.02 mm/y for group L at 10 years after surgery and penetration rates seemed to be almost constant with no significant difference after 3 years. Minimum liner thickness (5.3 mm for 48-mm socket in combination with 32-mm femoral head) and the second thinnest XLPE (6.3 mm in case of socket from 50 mm to 54 mm combined with 32-mm femoral head) was distributed in 25% and 72% with group L, respectively, and there were no significant differences in penetration rates between 5.3-mm- and 6.3-mm-thickness groups. CONCLUSION: Our study suggested that whether to select 26- or 32-mm diameters of femoral head does not affect XLPE wear in combination with this type of articulation.

Tailor-made surgical guide based on rapid prototyping technique for cup insertion in total hip arthroplasty.

BACKGROUND: A surgical guide made by the rapid prototyping (RP) technique for cup insertion in total hip arthroplasty might be useful to avoid malalignment of the cup, which indicates postoperative complications. METHODS: To address this research question, we applied a RP-based guide to 24 patients with their CT images. We designed it to fit onto the acetabular edge and to insert a Kirschner wire (K-wire) which indicated a planned cup direction. We intraoperatively placed it on the acetabular edge, inserted the K-wire through the guide on the superior acetabulum and implanted the cup while observing the alignment of the K-wire. We also recorded the additional time needed to use the guide. RESULTS: The mean cup accuracy between planned and postoperative alignments was 2.8 degrees (SD = 2.1 degrees ) for abduction and 3.7 degrees (SD = 2.7 degrees ) for anteversion. The mean additional time was 3.5 (range 2-6) min. CONCLUSION: We can use this guide with acceptable accuracy and without consuming an excessive amount of time.

Four-dimensional model of the lower extremity after total hip arthroplasty.

We have developed a four-dimensional (4D) model of the lower extremities after total hip arthroplasty in patients. The model can aid in preventing complications such as dislocation and wearing of the sliding surface. The skeletal structure and implant alignment were obtained from CT data. We applied registration method using CAD data to estimate accurate implant alignment from scattered CT data. The reconstructed three-dimensional (3D) skeletal model was combined with motion capture data that were acquired by an optical tracking system. We displayed the patient's skeletal movement and analyzed several parameters that relate to complications. The patient's skeletal model was superimposed onto video footage that was taken by a synchronized and calibrated digital video camera. For validation of the measurement error in this system, we used open MRI to evaluate the relative movement between skin markers and bones. This system visually represents not only the 3D anatomical structure, but also 4D dynamic functions that include the time sequential transitions of components and their positions. The open MRI results indicated that the average error in hip angle was within 5 degrees for each static posture. This system enables clinicians to analyze patient's motions on the basis of individual differences. We found that our system was an effective tool in providing precise guidance of daily postoperative motions that was individualized for each patient. This system will be applicable for surgical planning, assessment of postoperative activities, and the development of new surgical techniques, materials, and prosthetic designs.

A novel system of four-dimensional motion analysis after total hip arthroplasty.

We have developed a novel system of four-dimensional motion analysis after total hip arthroplasty (THA) that can aid in preventing dislocation by assessing safe range of motion for patients in several daily activities. This system uses skeletal structure data from CT and motion capture data from an infrared position sensor. A 3-D model reconstructed from CT data is combined with the motion capture data. Using this system, we analyzed hip motion when getting up from and sitting down in a chair or picking up an object while sitting in a chair in 17 patients (26 hips) who underwent THA. To assess the accuracy of this system's measurements, open MRI was used to evaluate positions of skin markers against bones in five healthy volunteers in various postures. No impingement between bones and/or implants was found in any subjects during any activities. However, mean angle at the point of maximum hip flexion was different for each patient. The open MRI results indicated that average error in hip angle of the present system was within 5 degrees for each static posture. The functional position of the pelvis during daily activities must be taken into account when assessing the real risk of dislocation. The present system enables dynamic analysis involving not only alignment of components and bones of each patient, but also individual differences in characteristics of daily motions. Further investigation using this system can help determine safe ranges of motion for preventing hip dislocation, improving the accuracy of individualized guidance for patients regarding postoperative activities.

Recovery of walking speed and symmetrical movement of the pelvis and lower extremity joints after unilateral THA.

In 17 patients with unilateral hip disease who underwent total hip arthroplasty (THA), the gait was analyzed preoperatively and 1, 3, 6, and 12 months after unilateral THA using a Vicon system to assess the recovery of walking speed and symmetrical movement of the hip, knee, ankle, and pelvis. The walking speed of these patients reached that of normal Japanese persons by 12 months after surgery. Walking speed was correlated with the range of hip motion on the operated side at 1 month postoperatively, and was correlated with the hip joint extension moment of force on both sides from 3 to 6 months after surgery. Before THA, asymmetry was observed in the range of the hip motion, maximum hip flexion, maximum hip extension, maximum knee flexion, as well as in pelvic obliquity, pelvic tilt, and pelvic rotation. There were no differences of the stride length or step length between both sides throughout the observation period. The preoperative range of hip flexion on the operated side during a gait cycle (21.3+/-7.9 degrees ) was significantly smaller than on the non-operated side (46.7+/-7.1 degrees ), and the difference between sides was still significant at 12 months after surgery (35.1+/-6.2 degrees on the operated side and 43.6+/-5.7 degrees on the non-operated side). The majority (74%) of the difference in hip motion range during this period was due to the difference in maximum extension of the hip. The increase in the range of pelvic tilt and the range of motion of the opposite hip showed an inverse correlation with the range of motion of the operated hip, suggesting a compensatory preoperative role. However, this correlation became insignificant after 6 months postoperatively. Asymmetry of the range of hip motion persisted at 12 months after THA in patients with unilateral coxoarthropathy during free level walking, while the operation normalized the spatial asymmetry of other joints and the walking speed prior to the recovery of hip motion.

Effectiveness of the ROBODOC system in preventing intraoperative pulmonary embolism.

Intraoperative pulmonary embolism occurs not only during cemented but also during cementless total hip arthroplasty (THA). We determined whether the ROBODOC femoral milling system can reduce intraoperative pulmonary embolism, by using of transesophageal echocardiography and hemodynamic monitoring. We did a prospective clinical trial with 71 patients (75 hips) who were divided into 2 groups: group 1, 46 patients (50 hips) who underwent cementless THA with preparation of the femoral canal using ROBODOC; group 2, 25 patients (25 hips) who underwent conventional cementless THA surgery in whom separate measurements were made during preparation of the femur, insertion of the stem and relocation of the hip. The incidence of severe embolic events was lower in group 1 than in group 2. Our findings suggest that the ROBODOC femoral milling system may reduce the risk of clinically significant pulmonary embolism during cementless THA.

Scintigraphic image patterns in dysplastic coxarthrosis: evaluation with reference to radiographic findings in 210 hips.

Little is known about scintigraphic image patterns in the various stages of coxarthrosis. We assessed bone scintigraphy in 159 patients (210 hips) with dysplastic arthrosis of the hip. Scintigraphic images were divided into 5 types related to the radiographic stages of the disease. The scintigraphic images showed little, if any, uptake in the stage of prearthrosis. In the early stage, we found an increase in uptake in the weight bearing area in 30% of cases. In the advanced stage, more than half of the cases had an increase in uptake in the medial side of the joint and in the weight bearing area. In the terminal stage, a marked increase in uptake in the weight bearing area was commonest. Since the osteoblastic reaction intensified, a marked increase in uptake was seen not only in the weight bearing area, but also throughout the entire joint. These types of scintigraphic patterns, which change with the stage of coxarthrosis, seem to reflect the natural course of the disease. All hips with rapid progression of the disease showed a marked increase in uptake of radionuclide the entire joint at earlier stages.

Embolic events during total hip arthroplasty: an echocardiographic study.

We performed transesophageal echocardiography on 88 patients treated with cementless or hybrid total hip arthroplasty (THA). We observed a significantly higher frequency of severe embolic events among patients without cup holes during insertion of press-fit cups (46.0%) than in patients with holes (15.6%) (P<.005). During stem insertion, severe embolic events occurred in 61.5% of hybrid operations and 5.9% of cementless operations. PaO(2), systolic blood pressure, and arterial oxygen saturation decreased significantly in severe embolic events (P<.05). The results indicate that embolic events may occur during THA whether or not cement is used. Based on these findings, we make several recommendations for technique modifications during insertion of both femoral and acetabular components in THA.

4-dimensional computer-based motion simulation after Total Hip Arthroplasty.

This paper represents a novel 4-dimensional(4D) computer-based motion simulation system for patients having had Total Hip Arthroplasty(THA). By constructing the skeletal model of the patient's lower extremity and measuring daily motions, we simulated the movement of the inner structures including the skeleton and the artificial joint. This system visually represents not only the 3-dimensional(3D) anatomical structure but also the 4-dimensional dynamic functions that represent the time sequential transitions of the position of each component. Clinicians can get detailed information of the movement of the hip joint quantitatively and give precise guidance for the patients with regard to postoperative daily motions. The measurement error was evaluated by performing experiments using OpenMRI and the results indicated sufficient accuracy of this system. We believe that this system enables clinicians to reveal the causes of complications after THA and encourages the development of new surgical techniques, materials. and designs of prostheses.