Clinical advantages of gradually reducing radius versus multi-radius total knee arthroplasty: a noninferiority randomized trial.

BACKGROUND: The rationale for gradually reducing radius (GR) femoral component aims to prevent flexion instability by gradually change the center of femoral rotation, unlike a discrete change by the multi-radius (MR) which is more common for most of total knee arthroplasties (TKA). However, no strong evidence has been reported the clinical significance of the GR design. METHODS: This patient-blinded, parallel, non-inferiority trial conducted between January 2018-December 2020. Patients with knee osteoarthritis consented for cruciate retaining TKA were randomly allocated to a GR or MR group. Primary outcome measures were knee functions at postoperative 6 and 12 months using the Knee injury and Osteoarthritis Outcome Score (KOOS). Secondary outcome measures were performance-based tests (30-s chair stand test, 40-m fast paced walk test, and 3-m timed up and go test), and knee motions. RESULTS: Sixty patients were enrolled and randomized; GR (n = 30) and MR (n = 30) group. The changes of KOOS at 6 and 12 months from baseline showed clinical meaningful for both GR and MR group. At 6 and 12 months postoperatively, there was no significant difference between both groups in all KOOS subscales. The length of stay was not different between GR and MR group (5.93 ± 1.44 vs 6.17 ± 1.86 days, p = 0.59). Patients on both groups presented similar performance-based tests. However, the improvement in degrees of knee motion for the GR group was significantly greater than the MR group (34.67 ± 12.52 vs 23.67 ± 12.59, p = 0.001). CONCLUSION: GR was noninferiority to MR for the functional outcomes and performances after TKA. The GR femoral component gave more knee motions than did the MR prostheses. LEVEL OF EVIDENCE: Level I, therapeutic study.

Outcome of revision surgery for adverse local tissue reactions in patients with recalled total hip arthroplasty.

INTRODUCTION: Recalls of total hip arthroplasty (THA) implants, including metal-on-metal (MoM) THA and dual taper stems, due to increased risk of adverse local tissue reaction (ALTR), represent a challenge for both surgeons and patients. This study aims to analyze the revision surgery outcomes for ALTR in patients with recalled THA implants. METHODS: A total of 118 consecutive patients who underwent revision surgery due to ALTR with recalled THA were analyzed. Sub-group analysis was performed for recalled MoM THAs, head-neck modular stems, and dual taper neck-stems. RESULTS: At a mean follow-up of 6.6 years, the complication and reoperation rates of the recalled THAs were 32.2% and 25.4% respectively. The most common post-revision complication was dislocation (16%). Revision of modular taper corrosion THA and high-grade intraoperative tissue damage were risk factors associated with post-revision complications. CONCLUSION: This study reports high complication and reoperation rates of recalled THAs at mid-term follow-up. The high revision surgery complication rates in both groups suggest the importance of a systematic evaluation of all THA patients with at-risk implants. LEVEL OF EVIDENCE: Level III, case control retrospective analysis.

Effect of postural changes on in vivo pelvic tilt and functional component anteversion in total hip arthroplasty patients with lumbar disc degenerations.

AIMS: The complex relationship between acetabular component position and spinopelvic mobility in patients following total hip arthroplasty (THA) renders it difficult to optimize acetabular component positioning. Mobility of the normal lumbar spine during postural changes results in alterations in pelvic tilt (PT) to maintain the sagittal balance in each posture and, as a consequence, markedly changes the functional component anteversion (FCA). This study aimed to investigate the in vivo association of lumbar degenerative disc disease (DDD) with the PT angle and with FCA during postural changes in THA patients. METHODS: A total of 50 patients with unilateral THA underwent CT imaging for radiological evaluation of presence and severity of lumbar DDD. In all, 18 patients with lumbar DDD were compared to 32 patients without lumbar DDD. In vivo PT and FCA, and the magnitudes of changes (ΔPT; ΔFCA) during supine, standing, swing-phase, and stance-phase positions were measured using a validated dual fluoroscopic imaging system. RESULTS: PT, FCA, ΔPT, and ΔFCA were significantly correlated with the severity of lumbar DDD. Patients with severe lumbar DDD showed marked differences in PT with changes in posture; there was an anterior tilt (-16.6° vs -12.3°, p = 0.047) in the supine position, but a posterior tilt in an upright posture (1.0° vs -3.6°, p = 0.005). A significant decrease in ΔFCA during stand-to-swing (8.6° vs 12.8°, p = 0.038) and stand-to-stance (7.3° vs 10.6°,p = 0.042) was observed in the severe lumbar DDD group. CONCLUSION: There were marked differences in the relationship between PT and posture in patients with severe lumbar DDD compared with healthy controls. Clinical decision-making should consider the relationship between PT and FCA in order to reduce the risk of impingement at large ranges of motion in THA patients with lumbar DDD. Cite this article: Bone Joint J 2020;102-B(11):1505-1510.

Effect of postural changes on in vivo pelvic tilt and functional component anteversion in total hip arthroplasty patients with lumbar disc degenerations.

AIMS: The complex relationship between acetabular component position and spinopelvic mobility in patients following total hip arthroplasty (THA) renders it difficult to optimize acetabular component positioning. Mobility of the normal lumbar spine during postural changes results in alterations in pelvic tilt (PT) to maintain the sagittal balance in each posture and, as a consequence, markedly changes the functional component anteversion (FCA). This study aimed to investigate the in vivo association of lumbar degenerative disc disease (DDD) with the PT angle and with FCA during postural changes in THA patients. METHODS: A total of 50 patients with unilateral THA underwent CT imaging for radiological evaluation of presence and severity of lumbar DDD. In all, 18 patients with lumbar DDD were compared to 32 patients without lumbar DDD. In vivo PT and FCA, and the magnitudes of changes (ΔPT; ΔFCA) during supine, standing, swing-phase, and stance-phase positions were measured using a validated dual fluoroscopic imaging system. RESULTS: PT, FCA, ΔPT, and ΔFCA were significantly correlated with the severity of lumbar DDD. Patients with severe lumbar DDD showed marked differences in PT with changes in posture; there was an anterior tilt (-16.6° vs -12.3°, p = 0.047) in the supine position, but a posterior tilt in an upright posture (1.0° vs -3.6°, p = 0.005). A significant decrease in ΔFCA during stand-to-swing (8.6° vs 12.8°, p = 0.038) and stand-to-stance (7.3° vs 10.6°,p = 0.042) was observed in the severe lumbar DDD group. CONCLUSION: There were marked differences in the relationship between PT and posture in patients with severe lumbar DDD compared with healthy controls. Clinical decision-making should consider the relationship between PT and FCA in order to reduce the risk of impingement at large ranges of motion in THA patients with lumbar DDD.

Outcome of Dual Mobility Constructs for Adverse Local Tissue Reaction Associated Abductor Deficiency in Revision Total Hip Arthroplasty.

BACKGROUND: Treatment of adverse local tissue reaction (ALTR) is challenging owing to high complications and poor outcomes after a revision surgery. As dislocation is the most common cause of reoperation, it is often necessary to use advanced articulations such as dual mobility. This study aims to evaluate the outcome and complication rates after revision surgery with dual mobility constructs, compared to constrained and conventional articulations in the setting of significant abductor deficiency due to ALTR. METHODS: Out of a total of 338 revision total hip arthroplasties for ALTR, 234 patients with a significant tissue necrosis and abductor muscle insufficiency (grade 3) were evaluated. The complication rates after revisions were compared between 42 hips with dual mobility implants, 24 hips with constrained liners, 104 hips with large diameter heads (36-40 mm), and 64 hips with small diameter heads (≤32 mm). RESULTS: After an average of 4 years of follow-up (2.8-8.6), the dual mobility articulation had no dislocation, compared to 4.1% and 15.5% for constrained liner and conventional articulations, respectively (P < .001). Utilization of dual mobility and constrained liner cup also did not increase the risk of nondislocation complications, including periprosthetic joint infection and periprosthetic fracture (P = .18 and .52). CONCLUSIONS: This study demonstrates significantly lower dislocation rates for dual mobility when compared to conventional articulations and comparable to constrained liners in cases of severe abductor deficiency due to ALTR, suggesting that dual mobility implants are viable surgical treatment alternatives to constrained liners to minimize dislocation during revision total hip arthroplasty in the setting of significant abductor deficiency due to ALTR.

Does Component Alignment Affect Patient Reported Outcomes following Bicruciate Retaining Total Knee Arthroplasty? An In Vivo Three-Dimensional Analysis.

This is an experimental study. Anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) retaining bicruciate retaining (BCR) total knee arthroplasty (TKA) have the potential to restore normal knee kinematics and thus improve patient outcome. Limited studies have examined the relationship between component alignment and patient-reported outcome measures (PROM). This study aims to determine (1) accurate three-dimensional (3D) component alignment of BCR TKA and (2) whether the component alignment of BCR TKA affects PROMs. The 3D modeling analysis was performed based on computed tomography images from 29 BCR TKAs. Component orientations were quantified for femoral and tibial components in the sagittal, axial, and coronal planes. The knee society scores (KSS) were collected preoperatively and postoperatively at 1-year follow-up. Multiple comparisons were performed to analyze the relationship between component alignment and patient outcomes. High variability was observed in the tibial component alignment (root-mean-square values: axial plane 6.6 degrees, sagittal plane 5.1 degrees, and coronal plane 4.0 degrees). At 1-year follow-up, significant improvement in KSS was noted in BCR TKA patients (p < 0.001). However, regression analysis adjusting for baseline KSS demonstrated the postoperative KSS was negatively associated with the posterior tibial slope (B [slope of the output of the regression analysis] = 2.597, p = 0.006). Patients with greater posterior tibial slopes were reported poorer postoperative functions at 1-year follow-up. Excessive posterior tibial slope may generate greater posterior force on the femur that leads to continuous overloading of the preserved ACL, suggesting optimal sagittal plane alignment of the tibial component may be important for the optimization of postoperative functions of BCR TKA patients.

Posterior tibial slope modification in osteoarthritis knees with different ACL conditions: Cadaveric study of fixed-bearing UKA.

Unicompartmental knee arthroplasty (UKA) in anterior cruciate ligament deficiency (ACLD) has been debated for decades after the development of highly cross-linked polyethylene. This study aims to evaluate the effect of posterior tibial slope on restoring adequate knee stability and flexion after UKA in patients with ACLD. A total of 15 fresh cadaveric knees were divided into three groups: intact ACL, partial ACLD, and complete ACLD. Fixed-bearing UKAs including 3-D-printed tibial inserts with the slopes ranging from 3° to 12° were performed using computer-assisted navigation. Blinded evaluation of knee motion and anterior knee translation with knees flexed 20° and 90° was conducted using KT-arthrometry and stress radiography. A 1° slope increase translated the knees anteriorly by 0.85 mm and 0.76 mm in 20° and 90° of knee flexion for a complete ACLD ( R = 0.7 and 0.8, respectively, p < 0.001) compared to 0.5-0.6 mm for the normal and partial ACLD groups, respectively. Setting a slope of 5-8° of UKA for an intact ACL maintained both the stability and the motion of native knees. No significant changes of knee translation and flexion ability were observed after leveling the slopes at 5-7° and 5-6° for partial and complete ACLD, respectively ( p > 0.05 for all comparisons). In conclusion, UKA in complete ACLD knees is challenging since 1° of slope change nearly doubles the degree of knee translation compared to ACL-intact knees. The optimum posterior tibial slopes for fixed-bearing UKA patients with partial and complete ACLD are 5-7° and 5-6°, respectively.

In Vivo analysis of spinopelvic kinematics and peak head-cup contact in total hip arthroplasty patients with lumbar degenerative disc disease.

Anterior instability after total hip arthroplasty (THA) has been described in patients with thoracolumbar kyphotic deformity. Although compensatory posterior pelvic tilt with subsequent increased functional anteversion has been described as the mechanism, there is a paucity of in vivo data. The purpose of our study was to compare pelvic tilt, anteversion, inclination, and position of head-cup contact points in patients with lumbar degenerative disc disease (DDD) and a matched patient cohort without DDD. A total of 50 THA, 18 hips with lumbar DDD and 32 hips without DDD, underwent CT imaging for 3D hip reconstruction. Component orientations and in vivo hip gait kinematics was quantified using a validated dual fluoroscopic imaging system. Hip kinematics and head-cup contact points were compared. Patients with lumbar DDD demonstrated decreased maximum (5.9° ± 4.2° vs. 9.3° ± 5.4°, p = 0.02) and minimum (2.4° ± 4.1° vs. 6.2° ± 5.6°, p = 0.01) anterior pelvic tilt, and increased maximum cup anteversion (29.3° ± 8.7° vs. 25.1° ± 8.1°, p = 0.05). The peak head-cup contact points were shifted closer to the anterior edge of the polyethylene (7.8 ± 1.7 mm vs. 9.6 ± 2.2 mm, p = 0.02). Patients with lumbar degenerative disc disease demonstrated increased posterior pelvic tilt, functional acetabular anteversion, inclination as well as shifting of the peak head-cup contact pattern significantly closer to an anterior edge, suggesting sagittal spinopelvic deformity may predispose to anterior instability in THA patients during upright activities. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Stair Climbing and High Knee Flexion Activities in Bi-Cruciate Retaining Total Knee Arthroplasty: In Vivo Kinematics and Articular Contact Analysis.

BACKGROUND: Bi-cruciate retaining (BCR) total knee arthroplasty (TKA) preserves both anterior and posterior cruciate ligaments with the potential to restore normal posterior femoral rollback and joint kinematics. However, there is limited information regarding articular contact behavior in the contemporary BCR TKA design during high knee flexion activities. This study aimed to investigate the articular knee contact performance in unilateral BCR TKA patients during strenuous flexion activities. METHODS: Twenty-nine unilateral BCR TKA patients were evaluated for both knees during single deep lunges, step-ups, and sit-to-stand (STS) using a validated combined computer tomography and dual fluoroscopic imaging system. Medial and lateral condylar contact positions were quantified during weight-bearing flexion. RESULTS: Contact excursions of the lateral condyle in BCR TKAs were significantly more anteriorly located than the contralateral non-operated knees during STS (-4.9 ± 3.1 vs -9.7 ± 4.6 mm, P < .05), single deep lunge (-5.7 ± 3.2 vs -10.0 ± 4.5 mm, P < .05), and step-ups (-4.8 ± 3.6 vs -9.1 ± 3.9 mm, P < .05). Contact points of BCR TKAs indicated reduced femoral external rotation during STS (2.1 ± 4.8° vs 7.7 ± 5.4°, P < .05), single deep lunges (1.8 ± 4.8° vs 7.0 ± 7.1°, P < .05), and step-ups (0.1 ± 4.1° vs 6.2 ± 4.9°, P < .05). Medial pivoting patterns were observed in only 59%, 56%, and 48% of the BCR TKA knees for step-ups, STS, and single deep lunge, respectively. CONCLUSION: The contemporary BCR TKA design demonstrated asymmetric femoral rollback, medial translation, as well as lateral pivoting in about half of the patient cohort, suggesting that in vivo tibiofemoral kinematic parameters were not fully restored in BCR patients during strenuous flexion activities.

Femoral mechanical-anatomical angle of osteoarthritic knees.

BACKGROUND: To perform total knee arthroplasty, some surgeons prefer to use a fixed valgus angle, for example 5° or 6°, for the distal femoral cut with every patient. This angle may be appropriate for some patients, but may not be for all. OBJECTIVE: To determine the proper angle of the distal femoral cut during total knee arthroplasty (TKA) in Thai patients with osteoarthritis of the knee. MATERIAL AND METHOD: A cross-sectional study was conducted of 80 osteoarthritic knees of 50 Thai patients with a mean age of 69 years (range 52-82, SD 7.64) who had received total knee arthroplasty at Chiang Mai University Hospital between January 2011 and March 2013. The femoral mechanical-anatomical (FMA) angle, femorotibial (FT) angle, mechanical femorotibial (MFT) angle, femoral bowing angle, femoral length, hip offset, gender, and age of the patients were analysed using multivariate regression analysis. RESULTS: Average FMA angle was 6.46° (range 4°-10°, SD 1.26°). The FMA angle was 6.85° and 5.28° in patients with varus and valgus deformity, respectively. Fifteen percent of all patients showed a FMA angle either less than 5° or greater than 7°. CONCLUSION: The average FMA angle of patients with gonarthrosis was 6.46°. If it is not possible to measure the FMA angle in Thai patients, 7° valgus cut angle is recommended for patients with varus deformity. Variation in this angle was high. Pre-operative measurement of FMA angle is beneficial for precise TKA.

Relationships between serum biomarker levels and clinical presentation of human osteosarcomas.

BACKGROUND: Currently, serum biomarkers play an important role as sensitive tools for monitoring the cancer development and progression. Each biomarker represents a specific pathogenesis and has different predictive capability. In order to identify their characteristics in human osteosarcoma, multiple potential biomarkers were analyzed simultaneously with clinical presentations. MATERIALS AND METHODS: Blood samples were collected from 28 osteosarcoma patients and 30 healthy matched controls. Specific clinical presentations were recorded, including: tumor volume, estimated based on three-dimensional MRI volumetric measurement; metastasis status; and histological cell types. Serum biomarkers analyzed by ELISA-based assays were bone-specific alkaline phosphatase (BALP), vascular endothelial growth factor (VEGF), hyaluronic acid (HA) and chondroitin sulfate WF6 (WF6). Serum lactate dehydrogenase (LDH) was analyzed by a photometric-based system. RESULTS: Serum BALP, LDH and WF6 levels of osteosarcoma patients were significantly higher than those of healthy controls, whereas HA and VEGF levels were not significantly different between the two groups. Serum BALP and LDH were positively correlated with tumor volume, (correlation coefficients 0.5 and 0.4, respectively). Serum BALP from metastasis and osteoblastic subtype group had a significantly higher level than that found in non-metastasis and non-osteoblastic subtypes group, respectively. Upon multivariate analysis, tumor volume was the only factor which correlated with BALP levels. CONCLUSION: Of the biomarkers analyzed in this study, serum BALP was the most reliable and sensitive for estimating tumor volume. A high level of serum WF6 reflects alteration of the extracellular matrix component of tumors. Both serum biomarkers can be expected to be further explored for use in specific clinical monitoring.