Discriminant validity and reproducibility of spatiotemporal and kinetic parameters during treadmill walking in patients with knee osteoarthritis.

BACKGROUND: Instrumented treadmills are potentially useful tools for the assessment of gait parameters in orthopaedic clinical settings, but their measurement properties remain uncertain. RESEARCH QUESTION: What is the discriminant validity and reproducibility of spatiotemporal and kinetic gait parameters measured by a pressure-instrumented treadmill at different speeds and inclinations in patients with knee osteoarthritis (KOA)? METHODS: A total of 54 patients with unilateral KOA and 23 healthy controls took part in the study. Step length, single-limb support duration and ground reaction force were recorded during level and uphill walking at 3 and 4 km/h using a commercially-available treadmill instrumented with an integrated pressure platform. We examined discriminant validity (difference between involved and uninvolved side as well as against healthy controls) and test-retest reproducibility (reliability and agreement). RESULTS: Significant side differences were observed for single-limb support duration and ground reaction force at touchdown in all conditions (P < 0.05). All the investigated gait parameters showed acceptable reliability and agreement, except step length at 4 km/h uphill. SIGNIFICANCE: We conclude that the pressure-instrumented treadmill used in this study may have good clinical utility for quantitative gait analysis in patients with KOA under different experimental conditions.

Quadriceps Neuromuscular Impairments after Arthroscopic Knee Surgery: Comparison between Procedures.

Quadriceps neuromuscular function remains impaired in the short- and long-term following knee arthroscopy for meniscal surgery and/or anterior cruciate ligament (ACL) reconstruction. The aim of this study was to compare quadriceps neuromuscular impairments in patients following meniscal surgery with and without ACL reconstruction. Thirty patients were tested six months after meniscal surgery with (n = 15) and without (n = 15) ACL reconstruction. We bilaterally assessed knee extension maximal voluntary contraction (MVC) torque using dynamometry, vastus lateralis thickness using ultrasound, quadriceps voluntary activation and evoked knee extension torque with transcutaneous electrical stimulation. Patient-reported outcomes were evaluated with the Knee Injury and Osteoarthritis Outcome Score (KOOS). Compared with meniscus patients, ACL patients demonstrated larger asymmetries in MVC torque (15% vs. 5%, p = 0.049) and vastus lateralis thickness (6% vs. 0%, p = 0.021). In ACL patients, asymmetries in MVC torque correlated with asymmetries in evoked torque (r = 0.622, p = 0.013). In meniscus patients, asymmetries in muscle activation correlated with KOOS quality of life (r = 0.619, p = 0.018). Patients demonstrated persistent quadriceps muscle weakness six months after ACL reconstruction, but not after isolated meniscal surgery. Quantitative and/or qualitative muscular changes likely underlie quadriceps muscle weakness in ACL patients, whereas activation failure is associated with poor quality of life in some meniscus patients.

Somatosensory Electrical Stimulation Does Not Improve Motor Coordination in Patients with Unilateral Knee Osteoarthritis.

Non-surgical treatment of knee osteoarthritis (KOA) is often focused on the motor component of KOA even though there is evidence that sensory dysfunctions play an important role in the impaired control of the affected joint. Excitation of sensory afferents can increase motor function by exploiting the nervous system's ability to adapt to changing environments (i.e., neuronal plasticity). Therefore, the aim of this study was to explore the acute effects of a single session (30 min) of sensory intervention targeting neuronal plasticity using low-frequency (10 Hz) somatosensory electrical stimulation (SES) of the femoral nerve. We evaluated the effects of SES on the position and force control of the affected knee and self-reported pain in KOA patients (n = 14) in a sham-controlled randomized trial. The results showed that SES did not improve measures of lower-limb motor coordination compared to sham stimulation in KOA patients, nor did it improve self-reported knee function and pain (all p > 0.05). In conclusion, despite sensory involvement in KOA, the sensory intervention used in the present explorative study did not relieve self-reported pain, which may underlie the absence of an effect on measures of motor coordination. In sum, the present explorative study showed that SES alone does not improve motor coordination in KOA patients.

Short-term functional advantages after medial unicompartmental versus total knee arthroplasty.

BACKGROUND: There are many uncertainties about the advantages and disadvantages of using unicompartmental (UKA) versus total knee arthroplasty (TKA) to treat patients with knee osteoarthritis. It is important to have sufficient early postoperative quadriceps strength for long-term, self-reported and gait-related outcomes after knee arthroplasty, but very limited comparative data exist regarding UKA and TKA patients. METHODS: This study assessed isometric quadriceps strength, spatio-temporal gait parameters (walking speed, step length, single-limb support phase) and self-reported outcomes (pain, function, stiffness) in 18 TKA and 18 UKA patients six months after surgery, as well as in 18 healthy controls. RESULTS: Quadriceps strength of TKA, but not of UKA patients, was lower than that of controls (P < 0.05). UKA patients demonstrated better gait function in terms of a longer single-limb support phase than TKA patients (P < 0.01), which agreed with better self-reported pain (P < 0.05), function (P < 0.01) and stiffness (P < 0.05) scores compared to TKA patients. CONCLUSIONS: Six months after surgery, UKA patients showed better short-term quadriceps strength and gait function compared to TKA patients, together with less self-reported knee pain and stiffness. Patients eligible for UKA may experience less functional impairments compared to those who require TKA.

Explosive and maximal strength before and 6 months after total hip arthroplasty.

Patients with unilateral hip osteoarthritis experience impairments in lower limb muscle function due to pain and disuse of the affected limb. The influence of hip osteoarthritis and subsequent total hip arthroplasty (THA) has mostly been evaluated by maximal strength tests, yet the functionally important explosive strength capabilities of hip and knee muscles are largely unknown. We aimed to evaluate hip and knee explosive and maximal strength in hip osteoarthritis patients before and after THA. Twenty-one patients with unilateral hip osteoarthritis were evaluated before and 6 months after THA. They performed rapid maximal contractions of hip (flexor, extensor, abductor, adductor) and knee (flexor, extensor) muscles, from which explosive and maximal strength asymmetries were evaluated (involved versus uninvolved limb). Before THA, the involved limb showed significantly lower hip flexor, extensor, adductor, and knee extensor explosive and maximal strength compared to the uninvolved limb. Six months after THA surgery, hip flexor, extensor and adductor maximal and explosive strength asymmetries persisted, except for knee extensors. Explosive, but not maximal strength of hip abductors and knee extensors was lower in the involved limb before surgery and the reduced explosive strength capabilities may compromise daily living activities in hip osteoarthritis patients. After hip replacement, explosive strength asymmetries of knee extensors resolved, yet lingering asymmetries in hip flexor muscles should receive focused attention during postoperative rehabilitation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:425-431, 2018.

Differences in trunk and thigh muscle strength, endurance and thickness between elite sailors and non-sailors.

Dinghy sailors lean their upper body over the windward side of the boat ('hiking') to keep the boat's balance and maximise its speed. Sustaining the hiking position is essential for competitive performance and this study examined sport-specific differences of muscles relevant for hiking in elite sailors. Knee extensor muscle strength as well as trunk muscle strength, muscle endurance and muscle thickness were assessed in elite dinghy sailors (n = 15) and compared to matched, non-sailing controls (n = 15). Isometric extensor strength was significantly higher in sailors at 60° (+14%) but not at 20° knee flexion. Sailors showed significantly higher trunk flexor (but not extensor) strength under isometric (+18%) and eccentric (+11%) conditions, which was associated to greater muscle thickness (rectus abdominis +40%; external oblique +26%) and higher endurance for ventral (+66%) and lateral (+61%) muscle chains compared to non-sailors. Greater muscles thickness and the particular biomechanical requirements to maintain the hiking position may drive the increases in isometric and eccentric muscle strength as well as ventral and lateral trunk endurance. The current findings identified sport-specific muscle function differences and provide performance benchmarks for muscle strength and endurance in elite sailors.

Reproducibility of gait parameters at different surface inclinations and speeds using an instrumented treadmill system.

Instrumented treadmill systems allow the practical assessment of gait parameters under several walking conditions. Aim of this study was to evaluate the reproducibility of gait parameters at different surface inclinations and walking speeds using an instrumented treadmill system in healthy individuals. A total of 20 subjects (10 women) with a mean age of 31 years were evaluated with an instrumented treadmill system (FDM-T, Zebris Medical GmbH) during two identical test sessions. Spatial (step length, step width, foot rotation), temporal (cadence, single-limb support, step time) and ground reaction force (heel force, toe force, time to heel force, time to toe force) gait parameters were assessed at three treadmill inclinations (level, uphill, downhill) and five speeds (2, 3, 4, 5, 6 km/h). Between-day reproducibility was evaluated with smallest detectable changes for agreement and intraclass correlation coefficients for reliability. Low agreement and reliability were observed for (i) step length, cadence and step time during slow (2 and 3 km/h) and uphill walking and (ii) time to heel force and time to toe force under the majority of walking conditions. The instrumented treadmill system used in this study provided reproducible measurements for the majority of the evaluated spatial, temporal and ground reaction force gait parameters in healthy individuals. The assessment of time to heel/toe force should be however avoided, and particular care should be taken for some spatial (step length) and temporal (cadence and step time) parameters while walking uphill and/or at slow speeds.

Clinical assessment of spatiotemporal gait parameters in patients and older adults.

Spatial and temporal characteristics of human walking are frequently evaluated to identify possible gait impairments, mainly in orthopedic and neurological patients, but also in healthy older adults. The quantitative gait analysis described in this protocol is performed with a recently-introduced photoelectric system (see Materials table) which has the potential to be used in the clinic because it is portable, easy to set up (no subject preparation is required before a test), and does not require maintenance and sensor calibration. The photoelectric system consists of series of high-density floor-based photoelectric cells with light-emitting and light-receiving diodes that are placed parallel to each other to create a corridor, and are oriented perpendicular to the line of progression. The system simply detects interruptions in light signal, for instance due to the presence of feet within the recording area. Temporal gait parameters and 1D spatial coordinates of consecutive steps are subsequently calculated to provide common gait parameters such as step length, single limb support and walking velocity, whose validity against a criterion instrument has recently been demonstrated. The measurement procedures are very straightforward; a single patient can be tested in less than 5 min and a comprehensive report can be generated in less than 1 min.

Hip muscle strength recovery after hip arthroscopy in a series of patients with symptomatic femoroacetabular impingement.

PURPOSE: The aim of the study was to prospectively evaluate hip muscle strength in a series of patients with symptomatic FAI after hip arthroscopy. METHODS: Hip muscle strength of eight patients (age: 29 ± 10 years) was evaluated preoperatively and 2.5 years after hip arthroscopy, and was compared to eight matched controls. Maximal voluntary contraction (MVC) strength was measured for all hip muscle groups. At follow-up, we used the symptom-specific well-being outcome to assess the acceptability of the health state related to the hip. RESULTS: Patients showed MVC strength increases for all hip muscles (9-59%, P<.05). At follow-up, only hip flexor MVC strength was lower for patients than controls (-18%, P<.05). At follow-up, four patients (out of eight) were "neither satisfied nor dissatisfied" with the health state of their operated hip. CONCLUSIONS: Patients with symptomatic FAI recovered their hip muscle strength to normal levels 2.5 years after hip arthroscopy, except for hip flexors. Although all patients showed good hip muscle strength at follow-up, half of them were not completely satisfied with their health state related to the hip.

Differences in gait characteristics between total hip, knee, and ankle arthroplasty patients: a six-month postoperative comparison.

BACKGROUND: The recovery of gait ability is one of the primary goals for patients following total arthroplasty of lower-limb joints. The aim of this study was to objectively compare gait differences of patients after unilateral total hip arthroplasty (THA), total knee arthroplasty (TKA) and total ankle arthroplasty (TAA) with a group of healthy controls. METHODS: A total of 26 TAA, 26 TKA and 26 THA patients with a mean (± SD) age of 64 (± 9) years were evaluated six months after surgery and compared with 26 matched healthy controls. Subjects were asked to walk at self-selected normal and fast speeds on a validated pressure mat. The following spatiotemporal gait parameters were measured: walking velocity, cadence, single-limb support (SLS) time, double-limb support (DLS) time, stance time, step length and step width. RESULTS: TAA and TKA patients walked slower than controls at normal (p<0.05) and fast speeds (p<0.01). The involved side of TAA and TKA patients showed shorter SLS compared to controls at both normal and fast speeds (p<0.01). Regardless of walking speed, the uninvolved side of TAA and TKA patients demonstrated longer stance time and shorter step length than controls (p<0.01). TAA patients showed shorter SLS of the involved side, longer stance time and shorter step length of the uninvolved side compared to the contralateral side at both normal and fast speeds (p<0.001). CONCLUSIONS: Gait disability after unilateral lower-limb joint arthroplasty was more marked for distal than for proximal joints at six months after surgery, with a proximal-to-distal progression in the impairment (TAA>TKA>THA). THA patients demonstrated no gait differences compared with controls. In contrast, TAA and TKA patients still demonstrated gait differences compared to controls, with slower walking velocity and reduced SLS in the involved limb. In addition, TAA patients presented marked side-to-side asymmetries in gait characteristics.

Validity of the intelligent device for energy expenditure and activity accelerometry system for quantitative gait analysis in patients with hip osteoarthritis.

OBJECTIVE: To evaluate the concurrent validity of an accelerometry-based system (Intelligent Device for Energy Expenditure and Activity) with a criterion instrument (Gaitrite) for the evaluation of spatiotemporal gait variables in orthopedic patients. DESIGN: Validity study. SETTING: Research laboratory in an orthopedic hospital. PARTICIPANTS: Men with unilateral hip osteoarthritis (N=26; mean age ± SD, 54±9y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Patients were asked to walk at normal and fast velocities while gait cycle, swing, double support, step length, cadence, and speed were concomitantly recorded with the 2 instruments. Concurrent criterion-related validity was examined using intraclass correlation coefficients and Bland-Altman limits of agreement. RESULTS: Intraclass correlation coefficients were acceptable for all gait parameters (range, .815-.997), except step length (.783). Limits of agreement were low for gait cycle, swing, and cadence, though relatively high for double support, step length, and speed. A significant bias between the 2 measuring instruments was consistently observed. CONCLUSIONS: In patients with hip osteoarthritis, quantitative gait analysis with the IDEEA accelerometry system was satisfactory for the main temporal gait parameters, while double support, step length, and walking speed quantifications were invalid. The IDEEA system should be used with caution, and modifications of the system are recommended for improved use in clinical practice and research.