Differences in hip torque ratios between individuals with femoroacetabular impingement syndrome and asymptomatic individuals: A cross-sectional study.

BACKGROUND: Hip torque ratios are considered a useful measure for patients with hip pain. However, evidence regarding this measure for patients with femoroacetabular impingement syndrome is scarce. The primary aim of this study was to compare hip external-internal rotation and abduction-adduction torque ratios between patients with femoroacetabular impingement syndrome and asymptomatic individuals. The secondary aim was to compare hip torque ratios between the asymptomatic group and femoroacetabular impingement syndrome patients grouped according to the severity of symptoms and functional limitations. METHODS: Hip abduction-adduction and external-internal rotation torque ratios of 134 individuals with femoroacetabular impingement syndrome and 134 asymptomatic matched controls was assessed through isokinetic testing. Severity of symptoms and functional limitations was assessed through the iHOT-33. Mann Whitney U and Kruskall-Wallis tests were used to compare hip torque ratios between asymptomatic individuals and patients with femoroacetabular impingement syndrome and to patients with femoroacetabular impingement syndrome with different severities of symptoms and functional limitations. FINDINGS: No differences were identified in hip abduction-adduction (U = 7659.5, p = 0.192) and external-internal rotation (U = 8787.5, p = 0.764) torque ratios between patients with femoroacetabular impingement syndrome and asymptomatic individuals. Hip abduction-adduction torque ratio was higher (p = 0.0127) in patients with a severe state (median = 1.80, IQR = 0.61) when compared to asymptomatic individuals (median = 1.52, IQR = 0.45) (moderate effect size, r = 0.45). INTERPRETATION: Patients with severe symptoms and functional limitations related to FAI syndrome presented greater hip abduction-adduction torque ratio than asymptomatic individuals, suggesting a decreased adduction torque capacity relative to abduction torque in this subgroup of femoroacetabular impingement.

Can the history of injury influence shoulder isokinetic torque parameters in volleyball players?

The aim of the present study was to compare shoulder internal rotator and external rotator isokinetic parameters in concentric and eccentric contractions between volleyball players with and without a history of shoulder injury. Thirty male volleyball players participated of this study, divided into two groups: with a history of injury (WHI) in the dominant shoulder (11 athletes; age: 19.4 ± 3.6 years) and no history of injury (NHI) (19 athletes; age: 18.3 ± 2.9 years). The peak torque (PT) and concentric (Con) and eccentric (Ecc) PT angles in internal (IR) and external rotation (ER) at velocities of 60 and 180°/s were measured. The conventional (Con_ER:Con_IR), functional spiking (Ecc_ER:Con_IR), and cocking ratios (Ecc_IR:Con_ER) were calculated. No significant differences were found between groups for PT and PT angle, or for conventional, functional spiking, and cocking ratios. However, the spiking ratio was considered low (0.87) in the WHI group. Moreover, for the spiking ratio in the WHI group, PT at 60°/s occurred at different angles. We conclude that previous injury in shoulder did not affect the peak torque, as well as conventional, spiking or cocking ratio. However, the PT angles at 60°/s used to calculate the spiking ratio shifted due the prior injury.

Joint position sense error and muscle torque ratios of agonist and antagonist muscles in the ankle and knee joints of young adults.

BACKGROUND: Many studies have investigated the correlation between muscle torque and joint position sense (JPS), but few studies have been performed on the correlation between torque ratio and JPS. OBJECTIVE: The aim of this study was to investigate JPS and muscle torque ratios of agonist and antagonist muscles in the ankle and knee joints of young adults. METHODS: A total of 38 right handed healthy participants, 12 males and 26 females, were recruited. All participants measured their peak torque of knee flexor/extensor and ankle dorsiflexor/plantar flexor by using a Biodex system. They also used the Biodex to assess the proprioception through active joint reposition sense test in knee and ankle joint. Peak torque of each muscle, agonist/antagonist torque ratio and JPS error were collected, and Pearson's correlation analysis was used to examine correlations between peak torque, torque ratio and JPS error. RESULTS: For knee joints, correlations were found between flexion and extension torque, extension torque and torque ratio, and torque ratio and JPS error (r= 0.825/p= 0.000, r=-0.482/p= 0.002, and r=-0.685/p= 0.000, respectively). For ankle joints, correlations were found between dorsiflexion and plantar flexion torques, plantar flexion torque and torque ratio, plantar flexion torque and JPS, and torque ratio and JPS (r= 0.654/p= 0.000, r=-0.621/p= 0.000, r=-0.563/p= 0.000, and r=-0.761/p= 0.000, respectively). CONCLUSIONS: JPS error of lower extremity joint may be more related with agonist/antagonist torque ratio rather than peak torque. Therefore, people who will have training for reducing JPS error need to consider torque ratio, too.

Effect of Extracorporeal Shockwave Therapy on Passive Ankle Stiffness in Patients With Plantar Fasciopathy.

Plantar fasciopathy (PF) is the most common cause of heel pain. Extracorporeal shockwave therapy (ESWT) improves the gait pattern in patients with PF. However, the effects of ESWT on the biomechanics of the ankle in these patients remains unclear. Sixteen participants were included in the present study. Of the 16 participants, 8 patients with PF were assigned to receive extracorporeal shockwave therapy, and 8 healthy participants served as an external control group. ESWT was applied to the PF group for 1500 pulses at an energy flux of 0.26 mJ/mm2 every 3 weeks for 3 sessions. The biomechanics of the ankle joints were then assessed using an isokinetic dynamometer, and a health-related quality of life questionnaire was administered at baseline and at the final follow-up session 12 weeks after the initial treatment. Passive stiffness was calculated and compared between the foot affected with PF, the opposite foot, and both feet of those in the healthy control group. The Kruskal-Wallis 1-way analysis of variance with repeated measures was performed, and statistical significance was considered present at the 5% (p ≤ .05) level. Ankle dorsiflexion in the affected limb increased from 14° ± 3° to 17° ± 2° after ESWT (p < .05). No statistically significant differences were noted in the strength of dorsiflexion or plantarflexion at baseline and after ESWT. However, a statistically significant increase in the ratio of strength in ankle dorsiflexion versus plantarflexion was found after ESWT (p < .05). No differences in the passive stiffness of the ankle joint were demonstrated. Patients reported an improved physical function score after ESWT (p < .05). An increased dorsiflexion/plantarflexion torque ratio and maximal dorsiflexion associated with decreased pain might contribute to the improved physical function after ESWT for PF.

EVIDENCE FOR ISOKINETIC KNEE TORQUE ASYMMETRIES IN MALE LONG DISTANCE-TRAINED RUNNERS.

PURPOSE/BACKGROUND: Strength asymmetries are related to knee injuries and such injuries are frequently observed among runners. The purpose of this study was to examine whether long-distance runners have symmetric performance during knee isokinetic testing at two angular velocities. METHODS: Twenty-three healthy and well-trained male long-distance runners performed open-chain isokinetic trials for assessment of concentric quadriceps and hamstrings contractions at velocities of 60 °·s(-1) and 240 °·s(-1). Data were compared between the lower limbs at different velocities. RESULTS: Peak torque and total work were similar between the limbs. Asymmetry was observed for knee flexor power at 240 °·s(-1) (237 ± 45 W and 205 ± 53 W, in the preferred and non-preferred limb, respectively). Asymmetry indexes for flexor power were different between the velocities tested (13.1% and 2.21% for 240 °·s(-1) and 60 °·s(-1), respectively). CONCLUSION: A limb asymmetry was observed among runners for knee flexor power, mainly at higher angular velocities (240 °·s(-1)). In addition, H/Q ratios were observed to be contraction velocity dependent. LEVEL OF EVIDENCE: 3.

Effect of rotation bump on removal torque of orthodontic mini-implants.

OBJECTIVES: This study is designed to evaluate the mechanical stability of orthodontic mini-implants with vertical grooves in rabbits. MATERIALS AND METHODS: This study was done from March 2011 to February 2012 in Dental Research Institute of Seoul National University. Thirty-two mini-implants in the control group and 32 in the rotation bump (RB) group were inserted in the tibias of 16 rabbits and were removed after two weeks and four weeks, respectively. The maximum insertion torque (MIT), maximum removal torque (MRT), torque ratio (TR) of MRT to MIT and removal angular momentum (RAM) were all measured at the time of removal. RESULTS: There were no significant differences between the two groups in MIT and MRT at two weeks or four weeks. However, TR and RAM at four weeks in the RB group were significantly higher than in the control group (P<0.05). TR of the RB group was significantly increased at four weeks (P<0.05). In both groups, RAM at four weeks was significantly higher than at two weeks (P<0.05). CONCLUSION: These results suggest that RB of the mini-implant could provide resistance to the removal rotation, although it did not increase the MRT.

Effect of rotation bump on removal torque of orthodontic mini-implants

OBJECTIVES: This study is designed to evaluate the mechanical stability of orthodontic mini-implants with vertical grooves in rabbits. MATERIALS AND METHODS: This study was done from March 2011 to February 2012 in Dental Research Institute of Seoul National University. Thirty-two mini-implants in the control group and 32 in the rotation bump (RB) group were inserted in the tibias of 16 rabbits and were removed after two weeks and four weeks, respectively. The maximum insertion torque (MIT), maximum removal torque (MRT), torque ratio (TR) of MRT to MIT and removal angular momentum (RAM) were all measured at the time of removal. RESULTS: There were no significant differences between the two groups in MIT and MRT at two weeks or four weeks. However, TR and RAM at four weeks in the RB group were significantly higher than in the control group (P<0.05). TR of the RB group was significantly increased at four weeks (P<0.05). In both groups, RAM at four weeks was significantly higher than at two weeks (P<0.05). CONCLUSION: These results suggest that RB of the mini-implant could provide resistance to the removal rotation, although it did not increase the MRT.

Screw Joint Stability under Cyclic Loading of Zirconia Implant Abutments / 대한치과보철학회지

PURPOSE: The purpose of this study was to evaluate the effect of abutment material on screw-loosening before and after cyclic loading. Among the different materials of abutments, zirconia and metal abutment were used. MATERIAL AND METHODS:: Two types of implant systems: external butt joint (US II, Osstem Implant, Korea) and internal conical joint (GS II, Osstem Implant, Korea) were used. In each type, specimens were divided into two different kinds of abutments: zirconia and metal (n = 5). The implant was rigidly held in a special holding to device ensure fixation. Abutment was connected to 30 Ncm with digital torque gauge, and was retightened in 30 Ncm after 10 minutes. The initial removal torque values were measured. The same specimens were tightened in 30 Ncm again and held in the cycling loading simulator (Instron, USA) according to ISO/FPIS 1480. Cycling loading tests were performed at loads 10 to 250 N, for 1 million cycles, at 14 Hz, (by subjecting sinusoidal wave from 10 to 250 N at a frequency of 14 Hz for 1 million cycles,) and then postload removal torque values were evaluated. RESULTS: 1. In all samples, the removal values of abutment screw were lower than tightening torque values (30 Ncm), but the phenomenon of the screw loosening was not observed. 2. In both of the implant systems, initial and postload removal torque of zirconia abutment were significantly higher than those of metal abutment (P .05). 4. In metal abutments, the removal torque ratio of GS II system (internal conical joint system) was lower than that of US II system (external butt joint system) (P .05). CONCLUSION: Zirconia abutment had a good screw joint stability in the condition of one million cycling loading.