Knee Scores of Patients with Non-Lateral Compartmental Knee Osteoarthritis Undergoing Mobile, Fixed-Bearing Unicompartmental Knee and Total Knee Arthroplasties: A Randomized Controlled Trial.

OBJECTIVE: To evaluate knee scores and clinical efficacies of patients with non-lateral unicompartmental knee osteoarthritis (OA) who randomly underwent mobile-bearing (MB) unicompartmental knee arthroplasty (UKA), fixed-bearing (FB) UKA, and total knee arthroplasty (TKA). METHODS: From September 2015 to February 2017, a prospective, randomized, parallel, single-center trial of 180 patients (78 males and 102 females; 63.3 ± 6.9 years) with non-lateral compartmental knee OA was performed in the first author-affiliated hospital. The patients were randomly divided into three groups (each group included 60 patients) and received medial cemented Oxford phase 3 MB UKA, medial cemented Link FB UKA, or cemented DePuy Sigma PFC TKA, respectively. A similar perioperative management and fast-track surgery program was carried out for all patients. The knee scores at 3-year follow-up after operation and clinical efficacies of these three groups of patients were recorded, investigated, and compared. RESULTS: Primarily, compared to the TKA group, the UKA groups (MB UKA and FB UKA) had shorter operative time (median 63.2 < 67.1 min), less bleeding (8.6 < 30.0 mL), earlier resumption of walking without crutches (3.0 < 8.0 days) and walking up and down the stairs (5.0 < 10.0 days) (P < 0.001), higher FJS scores (78.0 > 74.5) (P = 0.007), better results in all knee scores (except VAS and KSS function scores) (P < 0.05), and a larger maximum flexion angle of the knee at the 3-year follow-up (123.0° > 96.0°) (P = 0.001). Secondarily, compared to the TKA group, the MB UKA group showed better results in the Western Ontario and McMaster Universities index (WOMAC) stiffness (83.6 > 79.6), WOMAC total (86.3 > 83.2), Oxford knee score (OKS) (20.0 < 23.0), Forgotten Joint Score (FJS) (78.5 > 74.5), and a larger maximum flexion angle of the knee (123.0 > 96.0) (P < 0.05). Moreover, the FB UKA group showed higher Hospital for Special Surgery Knee Score (HSS) (91.0 > 88.5), WOMAC stiffness (84.3 > 79.6), WOMAC function (85.2 > 81.7), WOMAC total scores (87.6 > 83.2), and a larger maximum flexion angle of the knee (119.0° > 96.0°) than the TKA group (P < 0.05). Overall, there was no significant difference in all knee scores and maximum flexion angles of the knee for the MB UKA and FB UKA groups (P > 0.05). There was one case with original bearing dislocation in MB UKA group. One patient with displacement of the femoral component caused by a fall injury, and another patient, who lost his life in a car accident, were involved in the FB UKA group. There was an infection case and an intermuscular vein thrombosis case in TKA group. CONCLUSION: UKA showed more advantages than TKA; however, there was no significant difference between the MB UKA and FB UKA groups for treatment of non-lateral compartmental knee OA.

Real-time monitoring of stresses and displacements in cervical nuclei pulposi during cervical spine manipulation: a finite element model analysis.

OBJECTIVE: The objective of this study was to research the distribution of stresses and displacements in cervical nuclei pulposi during simulated cervical spine manipulation (CSM). METHODS: A 3-dimensional finite element model of C3/4~C6/7 was established. The detailed mechanical parameters of CSM were analyzed and simulated. During the process, the changes in stresses and displacements of cervical nuclei pulposi within the model were displayed simultaneously and dynamically. RESULTS: Cervical spine manipulation with right rotation was targeted at the C4 spinous process of the model. During traction, levels of stresses and displacements of the nuclei pulposi exhibited an initial decrease followed by an increase. The major stresses and displacements affected the C3/4 nucleus pulposus during rotation in CSM, when its morphology gradually changed from circular to elliptical. The highest stress (48.53 kPa) occurred at its right superior edge, on rotating 40° to the right. It protruded toward the right superior, creating a gap in its left inferior aspect. The highest displacement, also at 40° right, occurred at its left superior edge and measured 0.7966 mm. Dimensions of stresses and displacements reduced quickly on rapid return to neutral position. CONCLUSION: The morphology of the C3/4 nucleus pulposus changed during CSM with right rotation, and it created a gap in its left inferior aspect. Biomechanically, it is more safe and rational to rotate toward the healthy side than the prolapsed side of the intervertebral disk during CSM. Upon ensuring due safety, the closer the application force is to the diseased intervertebral disk, the better is the effect of CSM.

Influence of cervical spine position, turning time, and cervical segment on cadaver intradiscal pressure during cervical spinal manipulative therapy.

OBJECTIVE: The purpose of this study was to determine influences of cervical spine positions, turning times, and cervical segments on cadaver intradiscal pressure (IDP) during cervical spinal manipulative therapy (SMT). METHODS: We simulated cervical SMT with stretching and rotation on 7 fresh adult cadaver specimens in the material test system machine. The changes in IDP for cervical intervertebral disks (C3/4, C4/5, and C5/6) during 4 different stages of cervical SMT (physiologic state, end of the traction stage, turning stage, and finish time) were monitored. Five different cervical positions (extension 20°, extension 10°, neutral position, flexion 10°, flexion 20°) and 3 different turning times (0.06, 0.11, 0.16 second) of IDP were monitored, using micropressure sensors. RESULTS: The variable tendency of cervical IDP presents a "V"-shaped curve during SMT. The 4 stages of SMT had significantly different IDP (F=5498.956; P<.001). There were also significant differences in IDP between 5 cervical positions ([F=1371.216; P<.001], [flexion 20°>flexion 10°>neutral position>extension 10°>extension 20°]), 3 turning times ([F=419.530; P<.001], [0.06>0.11>0.16 seconds]), and 3 cervical segments ([F=84.282; P<.001], [C3/4