Does accelerometer-based portable navigation provide more accurate and precise cup orientation without prosthetic impingement than conventional total hip arthroplasty? A randomized controlled study.

PURPOSE: This prospective randomized controlled study examined whether accelerometer-based navigation resulted in more accurate or precise cup orientation than a conventional mechanical guide. We used a simulation to evaluate how cup orientation affected potential hip range of motion (RoM) and freedom from prosthetic impingement. METHODS: Sixty hips were randomly allocated 1:1 to accelerometer-based portable navigation or conventional guidance. Procedures were performed through a standard posterolateral approach and combined anteversion technique. Cup inclination, cup anteversion, and stem anteversion were measured using computed tomography (CT). Using CT-based simulation, we evaluated impingement-free potential RoM and the proportion of hips with potential RoM required for daily activities. RESULTS: Absolute cup inclination and anteversion error averaged 4.3° ± 3.2° and 4.4° ± 2.9° for the navigation cohort and 5.6° ± 3.7° and 5.7° ± 4.2° for the conventional cohort, with no significant differences. Navigation resulted in significantly less variation in anteversion error than the conventional guide (p = .0049). Flexion, internal rotation (IR) at 90° of flexion, extension, and external rotation (ER) averaged 123° ± 12°, 46° ± 13°, 50° ± 10°, and 73° ± 23°, respectively, in the navigation cohort and 127° ± 10°, 52° ± 14°, 45° ± 10°, and 63° ± 12°, respectively, in the conventional cohort (p = .15, .15, .03, and .03, respectively). Flexion > 110°, IR > 30° at 90° of flexion, extension > 30°, and ER > 30° were achieved by 93%, 90%, 100%, and 100% of hips, respectively, in the navigation cohort and 97%, 93%, 97%, and 100% of hips, respectively, in the conventional cohort, with no significant differences. CONCLUSIONS: Cup anteversion with the navigation system was more precise, but not more accurate, than with the conventional guide. The navigation cohort exhibited greater potential extension and ER than the conventional cohort, but no significant difference in impingement within the potential RoM required for daily activities. TRIAL REGISTRATION NUMBER: 29036. Date of registration: November 14, 2017.

Evaluation of the balance function before and after total knee arthroplasty using Berg balance scale.

INTRODUCTION: The purpose of this study was to evaluate balance function before and after total knee arthroplasty (TKA) using Berg balance scale (BBS). The study also aimed to identify factors associated with balance impairment. MATERIALS AND METHODS: Ninety-three knees in 90 patients were prospectively evaluated using their BBS scores, passive knee extension/flexion angles, Visual analogue scale for pain scores, hip-knee-ankle angles, and knee extensor/flexor muscle strengths before and after TKA. A total BBS score of less than 45 indicates an enhanced risk of multiple falls. Multivariate logistic regression models were performed to elucidate factors associated with post-operative BBS score. RESULTS: A significant difference in mean pre- and post-operative BBS scores were noted (49.3 ± 6.4 vs. 52.2 ± 4.7) (p < 0.05). The percentage of pre- and post-operative BBS scores less than 45 were 20% and 10% (p < 0.05). Rheumatoid Arthritis (RA), lower pre-operative BBS score, and larger post-operative knee flexion contracture were significantly associated with lower post-operative BBS score (p < 0.01). The post-operative knee flexion contracture greater than 10° was significantly associated with substantially high odds of post-operative BBS scores less than 45 (Odds ratio 7.6; 95% confidential interval 1.69-34.17). CONCLUSIONS: While TKA significantly improved BBS scores, 10% of the patients remained at a risk for multiple falls. RA, lower pre-operative BBS score, and post-operative knee flexion contracture greater than 10° retained balance impairment even after TKA.

Comparison of in vivo knee kinematics before and after bicruciate-stabilized total knee arthroplasty during squatting.

BACKGROUND: No studies have directly evaluated kinematic changes during squatting before and after bicruciate-stabilized total knee arthroplasty (BCS-TKA) with the dual cam-post mechanism and asymmetric surfaces. This study investigated the effect of BCS-TKA on changes to pre- and postoperative skeletal knee kinematics, to identify factors associated with postoperative skeletal kinematic parameters. METHODS: Seventeen knees in 17 patients were prospectively recruited before primary TKA for advanced medial knee osteoarthritis. Subjects underwent BCS-TKA and were evaluated more than 1 year postoperatively. In vivo dynamic skeletal knee kinematics were evaluated using periodic radiographic images collected during squatting to quantify the tibiofemoral functional extension/flexion angle, anteroposterior (AP) translation, and axial rotation angle using image-matching techniques. Rotational alignments of femoral and tibial components were measured postoperatively using computed tomography images. RESULTS: The pre- and postoperative tibiofemoral functional extension/flexion angles during squatting were 12.2° ± 6.7°/100.1° ± 16.8° and 9.6° ± 8.6°/109.4° ± 16.8°, respectively, with a significant difference in flexion angle (p < .05). Total AP translation was significantly larger postoperatively than preoperatively (10.8 mm ± 3.7 mm vs. 14.4 mm ± 4.2 mm, respectively; p < .05). The pre- and postoperative total rotation angles were 6.6° ± 3.0° and 6.4° ± 3.7°, respectively, indicating no significant difference. The pre- and postoperative tibiofemoral functional flexion angles were significantly associated with each other (p = .0434, r = .49). The postoperative total rotation angle was significantly smaller when the total component rotational mismatch angle between the femoral and tibial components was above 5° vs. below 5° (4.6° ± 2.7° vs. 8.3° ± 3.9°, respectively; p < .05). CONCLUSIONS: BCS-TKA significantly increased the tibiofemoral functional flexion angles, with larger AP translation postoperatively. Both preoperative skeletal kinematics and surgical techniques affected the skeletal kinematics of the replaced knee. A total component rotational mismatch angle greater than 5° significantly decreased postoperative total knee rotation during squatting.

Tibiofemoral kinematics in healthy and osteoarthritic knees during twisting.

PURPOSE: The purpose of this study was to determine the in vivo kinematics of healthy knees and those with osteoarthritis (OA), during twisting using density-based image-matching techniques. METHODS: Five healthy subjects and 26 patients with medial knee OA performed twisting under periodic X-ray imaging. RESULTS: The tibiofemoral rotation at the ipsilateral/contralateral twist in healthy and OA knees were 11° ± 9.3° externally/9.5° ± 5.6° internally (p < 0.05) and 4.4° ± 7.2° externally/2.7° ± 8° internally (p < 0.05), respectively. CONCLUSIONS: The kinematic analysis of OA knees during twisting revealed significantly smaller tibiofemoral rotation than those of healthy knees.

Anatomical Evaluation of Lumbar Arteries for Lateral Lumbar Interbody Fusion with Magnetic Resonance Imaging.

INTRODUCTION: Lateral lumbar interbody fusion (LLIF) is becoming a more common surgical treatment option for adult degenerative lumbar conditions. LLIF is a mini-open access technique with wound retractors, and postoperative hematoma due to segmental vessels injury is reported. Thus, it is considered that there is a need to conduct detailed preoperative examinations to identify where the lumbar vessels are. As far as we know, there are only a few studies investigating the location of the lumbar arteries. This study evaluates the anatomical position of lumbar arteries using magnetic resonance imaging (MRI). METHODS: We studied 101 MRIs of patients with lumbar disease. The length from the upper and lower end plates of the vertebra to the lumbar arteries was measured. The measurement was conducted with coronal MRI images of every quarter slice of L1 to L4 vertebrae. We also investigated sagittal MRI images to determine whether the lumbar vessels are located on intervertebral disc in each level from L1/2 to L5/S1. RESULTS: The lumbar vessels are not always located at the center of the vertebrae. Some lumbar vessels are located within 8 mm from the end plates. Especially in L4, the lumbar vessels tended to go down from the anterior cranial side to the posterior caudal side (P < 0.01). 8, 24, and 54 lumbar vessels are located at the anterior quarter, the center, and the posterior quarter slice of the vertebrae, respectively, in L4. There were seven lumbar vessels in total located on the vertebral disc level. CONCLUSIONS: It is necessary to investigate where the lumbar arteries are located to prevent its injury in LLIF, because the lumbar artery is not always located at the center of a vertebra. MRIs may provide a valuable information to avoid vascular injury during LLIF.

Revascularization of the necrotic femoral head after traumatic open anterior hip dislocation in a child: a case report.

INTRODUCTION: Avascular necrosis of the femoral capital epiphysis is the most serious complication after traumatic dislocation of the hip in children. This case report discusses the localization and revascularization of the necrotic femoral head following rarely experienced traumatic open anterior hip dislocation in children. CASE PRESENTATION: Our patient was an 11-year-old Japanese boy who had open anterior hip dislocation sustained in a traffic accident. Reduction of the hip joint was performed in an emergency operation, and he was evaluated using serial gadolinium-enhanced magnetic resonance imaging. T1-weighted magnetic resonance images showed two bands with low signal intensity in the femoral capital epiphysis on coronal and oblique axial planes, indicating the existence of avascular osteonecrosis of the femoral head. We observed gadolinium enhancement in the central region of the epiphysis, where the area between the two bands with low signal intensity was located. Serial assessment with enhanced magnetic resonance images during a non-weight-bearing period of 1.5 years after injury showed revascularization starting from the central region and converging toward the peripheral region. Although the patient had leg-length discrepancy due to the early epiphyseal closure, non-weight-bearing treatment for the avascular osteonecrosis of the femoral head achieved a favorable outcome without any hip joint dysfunction, pain, or sign of secondary osteoarthritic change within 4.5 years after injury. CONCLUSION: We confirmed the revascularization process of the necrotic lesion in the femoral capital epiphysis in an 11-year-old boy using serial gadolinium-enhanced magnetic resonance imaging. Conservative non-weight-bearing treatment achieved a favorable outcome.

Do component position and muscle strength affect the cup-head translation during gait after total hip arthroplasty?

INTRODUCTION: This study examined whether the component position or muscle strength affects the cup-head translation under in vivo weight-bearing conditions after total hip arthroplasty (THA). We hypothesized that there was a correlation between the hip offset or abductor strength and cup-head translation during gait. MATERIALS AND METHODS: We prospectively evaluated 31 patients undergoing unilateral cementless primary THA. The cup height, cup/stem offset, and limb length discrepancy were measured on anterior-posterior bilateral hip radiographic images. The isometric muscle strength of the lower limbs was quantified using a handheld dynamometer. Continuous radiographic images were recorded during gait, and cup-head translation was analysed using a computer-assisted method. RESULTS: The average cup height, cup/stem offset, and limb length discrepancy were - 3.8 ± 5.1 mm, 1.2 ± 5.2 mm/- 0.7 ± 7.7 mm, and - 2.1 ± 5.2 mm, respectively. The average hip abductor/flexor and knee extensor strength were 86% ± 18%/85% ± 17% and 88% ± 17% of the contralateral healthy hip, respectively. The average cup-head translation during swing phase of gait was - 0.003 ± 0.31 mm. Multiple regression analyses found no significant independent predictors of cup-head translation (p > 0.05). CONCLUSIONS: The component position or muscle strength did not significantly influence cup-head translation during gait after well-positioned primary THA.

Recreational sports, workout and gym activities after total knee arthroplasty: Asian cohort study.

This study aimed to evaluate sports activities after total knee arthroplasty in an Asian cohort using 2011 Knee Society scoring system. The average scores for satisfaction and expectation about sports-related activities were 4.9 (61%) and 3.5 (70%), respectively. Most patients mainly opted for low-impact sports. Multivariate analysis showed that higher score of 'standard activities' and 'walking & standing', better range of motion, and older age were associated with higher scores of satisfaction and expectation about sports-related activities. In conclusion, improvement of activities of daily living could provide higher satisfaction and expectation about performing recreational sports, workout and gym activities.