Patellar shift ratio (PSR) is the optimal measurement for characterising lateral patellar shift and a reliable predictor of recurrent patellar dislocation.

PURPOSE: To propose a new measurement, the patellar shift ratio (PSR), for characterising lateral patellar shift; to determine its diagnostic accuracy in predicting recurrent patellar dislocation (RPD); and to identify the effect of patellar tilt and morphology on shift measurements. METHODS: Variables including the PSR, bisect offset (BSO), BSO adjusted by trigonometric analysis, linear patellar displacement (LPD) distance and congruence angle were measured on axial computed tomography (CT). Furthermore, PSR was classified into grades determined by the threshold generated by receiver operating characteristic (ROC) curves. Youden's index was used to identify the ideal threshold on the curve. The area under the ROC curve (AUC) values and likelihood ratios were calculated to assess diagnostic performance in predicting RPD. Correlation analysis was conducted to identify the effects of lateral tilt and the Wiberg index on lateral shift. Intra- and interobserver reliability were evaluated using the intraclass correlation coefficient. RESULTS: The study included 54 RPD patients and 54 controls matched by sex and age. The threshold for PSR was 24.3% (sensitivity, 96.30%; specificity, 85.19%). AUCs were categorised as excellent for all protocols (P < 0.001). The positive likelihood ratio of the PSR for predicting RPD was 6.50. PSR was categorised in terms of lateral trochlear quadrants consisting of 25% increments. Lateral patellar tilt showed a strong positive correlation with BSO (P < 0.001); moderate correlations with PSR, LPD distance and adjusted BSO (P ≤ 0.001); and a weak correlation with congruence angle (P = 0.034). The Wiberg index presented a positive moderate correlation with BSO (P < 0.001), while no correlation was found with PSR, LPD distance, or congruence angle (n.s.). All parameters showed good repeatability (intraobserver) and reproducibility (interobserver). CONCLUSIONS: The PSR showed excellent diagnostic performance as indicated by likelihood ratios, measurement accuracy (being relatively resistant to the effects of tilt and the Wiberg index), and intra- and interobserver reliability. The optimal PSR threshold for predicting RPD risk was 24.3%, and the grade of PSR (normal, 1-4) was also a reliable and easily calculated predictor of RPD. This quantifying method to characterise lateral patellar shift is an alternative useful method for clinical assessments of RPD patients and for research on patellofemoral congruence. LEVEL OF EVIDENCE: Level III.

Mechanoresponsive and lubricating changes of mandibular condylar cartilage associated with mandibular lateral shift and recovery in the growing rat.

OBJECTIVE: The in vivo mechanoresponsive and lubricating changes of the mandibular condylar cartilage (MCC) associated with mandibular lateral shift (MLS) and recovery are poorly understood. Using growing rats, we investigated whether the expression of mechanoresponsive factors, including proteoglycan-4 (PRG4), Indian hedgehog (Ihh) and transforming growth factor-ß1 (TGF-ß1), would be affected by MLS. We also investigated whether these changes could recover to the control level after a 2-week treatment reversal (TR). MATERIALS AND METHODS: The MLS appliances were placed for 2 or 4 weeks in 5-week-old rats and removed from 7-week-old rats in the TR group. The MCC was analysed histomorphometrically by toluidine blue staining. Reverse transcription-polymerase chain reaction and immunohistochemistry were performed to evaluate the expression of PRG4, Ihh, PTHrP (parathyroid hormone-related protein), TGF-ß1, Matrix metallopeptidase 13 (MMP-13) and a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5). RESULTS: A thickened superficial layer and an enhanced expression of PRG4 were detected in MLS groups. PTHrP-Ihh expression correlated positively with the up-regulation of PRG4. TGF-ß1 expression decreased in the early stage of MLS but recovered to the control level in the TR group. A significantly enhanced expression of MMP-13 in MLS groups was detected. CONCLUSION: MLS treatment, which acted on the growth stage of rats, affected the morphology and expression of lubrication factor in the MCC. Elimination of this mechanical stimulus may help MCC recover to normal conditions. CLINICAL RELEVANCE: Our study supports that the adaptive changes of MCC, which are caused by mandibular functional deviation, could be largely recovered by early treatment.

Anatomical Variations of Vertebrobasilar Artery are Closely Related to the Occurrence of Vertebral Artery Dissection-An MR Angiography Study.

GOAL: Intracranial arterial dissection is a major cause of ischemic stroke and subarachnoid hemorrhage in relatively young patients. We assessed the hypothesis that the tortuosity of the vertebrobasilar artery is associated with the occurrence of vertebral artery (VA) dissection, using MR angiography (MRA). MATERIALS AND METHODS: This study enrolled 43 patients with VA dissection, and 63 age- and sex-matched healthy subjects were used as the controls. MRA was employed to evaluate the presence of dominant VA and the lateral shift of vertebrobasilar junction in both groups. The VA diameters were considered different when the difference was greater than .3 mm. These anatomical variations were divided into 3 types: Type 1 (vertebrobasilar junction within 2 mm from the midline), Type 2 (>2 mm-lateral shift of vertebrobasilar junction to the ipsilateral side of the dominant VA), and Type 3 (>2 mm-lateral shift of vertebrobasilar junction to the contralateral side of the dominant VA). FINDINGS: The presence of dominant VA and the lateral shift of vertebrobasilar junction were more prevalent in patients with VA dissection than in the controls (OR: 3.46, P = .013, and OR: 4.51, P = .001, respectively). The lateral shift of vertebrobasilar junction was classified into Type 1 (n = 6), Type 2 (n = 13), and Type 3 (n = 17) among patients with VA dissection, while into Type 1 (n = 20), Type 2 (n = 8), and Type 3 (n = 7) among the controls. Type 3 predominance was observed in patients with VA dissection (P = .02). CONCLUSIONS: Anatomical variations of the vertebrobasilar artery may play an important role in the occurrence of VA dissection.

The occurrence of lateral shift in cervical dystonia.

Aim of this study is to identify factors contributing the occurrence of neck lateral shift (LS) in patients with cervical dystonia (CD). A retrospective analysis focused on the treatment with botulinum toxin (BTX) was conducted on 38 consecutive idiopathic CD patients comparing subjects with and without LS. The main result was the evidence of a significantly higher BTX inter-side dose difference in patients with LS suggesting that this uncommon phenotype may be an artifact of chronic therapy with BTX.

Lumbar lateral shift in a patient with interspinous device implantation: a case report.

BACKGROUND: Lumbar lateral shift (LLS) is a common clinical observation but has rarely been described in a patient with a history of lumbar surgery. The purpose of the current case report was to describe the use of the McKenzie Method of Mechanical Diagnosis and Therapy (MDT) in the multi-modal treatment of a patient with an LLS and a history of multiple surgical procedures in the lumbar spine, including interspinous process device (IPD) implantation. CASE DESCRIPTION: A 72-year-old female with chronic low back pain (LBP) and a surgical history in the lumbar spine was referred to physical therapy for radiating leg pain and presented with a right LLS. Her chief complaints included sitting for long periods, vacuuming and ascending stairs into her home. OUTCOMES: The patient was treated during eight visits over 30 days. Treatment interventions included manual shift correction, self-correction and management, joint mobilisation below the level of IPD implantation ,neurophysiology education, and development of a home exercise programme. At discharge, her leg pain was resolved and all goals had been met. The patient reported maintenance of gains at 6-month follow-up. DISCUSSION: Utilisation of the MDT approach, including LLS correction, produced positive outcomes in a complex patient with previous IPD implantation. Future research should investigate treatment and outcomes after invasive spinal procedures in similar patient populations to better inform clinical management. LEVEL OF EVIDENCE: 4.

Reversible Effects of Functional Mandibular Lateral Shift on Masticatory Muscles in Growing Rats.

In this study, we aimed to determine the effects of functional mandibular lateral shift (FMLS) on the muscle mass, fiber size, myosin heavy chain fiber type, and related gene expression in masticatory muscles (masseter and temporalis), as well as whether the baseline levels could be recovered after FMLS correction in growing rats. The FMLS appliance was placed to shift the mandible leftward by approximately 2 mm. After FMLS placement for 2 and 4 weeks, the muscles on the left side had significantly lower wet weight, mean cross-sectional area, and proportion of type IIa fibers than those on the right side or in the control groups (p < 0.05), with downregulation and upregulation of IGF-1 and GDF-8 gene expression, respectively (p < 0.05). Following 2 weeks devoted to recovery from FMLS, the muscle parameters in the recovery group were not significantly different to those of the control group, and IGF-1 expression in the left-side muscles was enhanced and GDF-8 expression was simultaneously suppressed. These findings indicate that the masticatory muscle changes induced via FMLS tend to revert to normal conditions if the intervention is eliminated at an early stage. Therefore, appropriate orthodontic treatment for FMLS during the growth period is advisable to prevent asymmetric alterations in masticatory muscles.

Lateral shift of the femoral condyle after total knee arthroplasty: simulation using 2D-templates of the medial pivot design on knee radiographs of young Japanese patients.

BACKGROUND: Total knee arthroplasty (TKA) is an established surgical treatment for advanced knee osteoarthritis by which patients can expect improvement of knee pain and function. Although many surgeons have investigated limb alignment after TKA, changes in coronal positional relation between the femur and tibia are not known well. METHODS: Radiographs of 105 knees of young Japanese patients between 20 and 49 years-old (60 men and 45 women) without osteoarthritic changes who received arthroscopic surgeries at our hospital were used in this study. Using 2D-templates of the medial pivot design (the FINE total knee), we simulated TKA on a SYNAPSE-PACS software. First, the femoral component was placed in normal knee alignment and then was merged to the medial concave of the insert where the tibial component was placed in neutral alignment. The length of the mediolateral shift of the femoral component was measured as an estimate of lateral shift of the femoral condyle, of which association with radiographic parameters including the femorotibial angle (FTA), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA) was analyzed. Subjects were classified into three groups according to the femoral component size that was chosen in simulation of TKA, and the lateral shift of the femoral condyle was compared between groups. RESULTS: The estimated mean lateral shift of the femoral condyle was 5.99 ± 1.98 mm and was greater in males than females (p < 0.05). Also, it was most highly correlated with the medial proximal tibial angle (MPTA) (r = - 0.553, p < 0.01). A group receiving larger component sizes significantly shifted more laterally compared with a group receiving smaller component sizes (p < 0.01). CONCLUSIONS: These results suggest that the coronal positional relation between the femur and tibia is altered and subsequent ligament imbalance may occur after mechanically aligned TKA using the medial pivot design.

Knee joint kinematics of the pendulum test in children with and without Down syndrome.

BACKGROUND: The Wartenberg pendulum test is a common clinical test that is used to measure stiffness about the knee in persons with and without disabilities such as cerebral palsy and Down syndrome (DS). Adults and adolescents with DS show fewer number of swing cycles and a lower relaxation index than healthy controls. However, it is not clear if children with DS show a similar trend compared to typically developing (TD) children. RESEARCH QUESTION: Was the knee joint kinematics different between children with and without DS during the pendulum test? METHODS: Thirteen children with DS and 13 TD children participated in this study. There were two load conditions: no load (NL) and with ankle load (AL) equal to 2 % of the subject's body weight. Five trials of a pendulum test were collected for each condition. RESULTS: The DS group showed a smaller first flexion excursion, a lower relaxation index, lower mean and peak velocities and accelerations during the first and second flexion and extension, and greater variability of acceleration during the first flexion than the TD group across both load conditions. This suggests that the DS group may have greater stiffness of the knee than the TD group to compensate for joint instability. SIGNIFICANCE: The pendulum test appears to be a valid test to evaluate the passive stiffness of the knee in children with DS. The lower relaxation index in children with DS suggests that larger bursts of quadriceps may be activated during a pendulum test, particularly in the first flexion excursion, to assure the knee joint stability.

Stimulus-driven attention modulates the release of anticipatory postural adjustments during step initiation.

OBJECTIVE: Step initiation can be modified by environmental stimulations, suggesting the involvement of stimulus-driven attention. Therefore, we assessed the influence of attentional status during step preparation. METHODS: Fourteen healthy, young subjects were presented with an auditory oddball paradigm in which an infrequent "target" stimulus was presented among frequent "standard" stimuli. An imperative visual "Go" signal for step initiation was presented 1.4s after the auditory stimulus. Both the P300 event-related potential (associated with the auditory attention task) and the trajectory of the centre of pressure (associated with step initiation) were recorded. RESULTS: When presented before the visual "Go" signal, the auditory stimuli prompted the early release of low-amplitude anticipatory postural adjustments, not followed by step execution. They occurred twice as frequently in the "target" condition as they did in the "standard" condition. P300 component was greater after presentation of the target stimulus than after presentation of the standard stimulus. CONCLUSION: Stimulus-driven attention can modify the release of anticipatory postural adjustments. SIGNIFICANCE: The cortical integration of an auditory stimulus (as evidenced by the P300 component) in a subject conditioned to initiate gait appears to release postural adjustments via two different attentional mechanisms: an "alerting effect" and an "orienting effect".

Classification-based approach for management of an adolescent with LBP, lower extremity pain, and a relevant postural deformity.

A 15-year-old female presented to physical therapy 2 months after a traumatic injury with severe low back pain, referred unilateral leg pain below the knee, and a lumbar lateral shift. A classification-based approach, mechanical diagnosis and therapy, was utilized to identify the patient with respect to a particular subgroup, and interventions were applied according to symptomatic response to loading strategies, sustained and repeated movements. Outcome measures included the Modified Oswestry Disability Questionnaire (MODQ) and a visual analog scale (VAS) for pain rating. After nine visits (4 weeks), there was a 60% improvement in MODQ score, 0/10 pain on the VAS, and the patient resumed participation in recreational activities. At the 1-year follow-up, there was a 78% overall improvement in MODQ score with continued 0/10 rated pain. Improvements after nine visits and at the 1-year follow-up both exceeded the minimal clinically important difference for the MODQ.

Manual correction of an acute lumbar lateral shift: maintenance of correction and rehabilitation: a case report with video.

The acute onset lumbar lateral shift, otherwise known as a list or acute scoliosis, is a common clinical observation associated with low back pain. In general orthopaedics, the presence of a lateral shift is associated with a poor prognosis; however, a manual correction method devised by McKenzie is claimed to produce rapid reversal of the deformity and reduction in pain. This single-case report presents the details of the McKenzie Mechanical Diagnosis and Treatment (MDT) management of a major right-sided lateral shift, which includes the manual correction technique, self-correction and management, prophylaxis, pain ablation, and rehabilitation to a high level of athletic function, with long-term follow-up at 9 months. The lateral shift is widely accepted as being associated with disc pathology, but the exact mechanism of shift production remains speculative. hypotheses include muscle spasm, avoidance of irritation of a spinal nerve, and space-occupying or space-deficient disc mechanics. The hypotheses used to explain the lateral shift phenomena are discussed. (Case report is supplemented by video stream, available at jmmtonline.com/).