Progressive submaximal effort hamstring muscle endurance is reduced after reconstruction of the anterior cruciate ligament

BACKGROUND

Endurance capability in the muscles controlling the knee is poorly understood post anterior cruciate ligament (ACL) reconstruction, despite many sporting activities requiring notable muscle endurance. The hamstring muscles, when active, provide important anatomical support to protect the reconstructed graft. In the absence of good hamstring endurance, fatigue may predispose individuals to re-injury.

OBJECTIVE

To assess whether ACL reconstruction (ACLR) with a hamstring graft leads to reduced hamstring endurance 9-13 months post-surgery.

STUDY DESIGN

A cross-sectional inter-limb comparison study was undertaken with participants 9-13 months after an ACLR with a hamstring graft, and a group of age, sex, and activity-matched controls. There were 22 participants in each group.

METHOD

Submaximal hamstring endurance was measured using a progressive fatigue test on an isokinetic dynamometer at a joint angular velocity of 120°/second. The dependant variable was the maximum number of repetitions performed. Statistical comparisons were made across injured, uninjured and control group limbs.

RESULTS

There was a significant (p < 0.05) deficit in hamstring endurance observed between the injured leg (mean: 111 repetitions, SD 49) and uninjured leg (mean: 136 repetitions, SD 67) of the ACL group, but not between the uninjured and control group legs (mean: 124 repetitions, SD 50).

CONCLUSION

The 18% deficit in submaximal hamstring endurance across the ACL-reconstructed individual's limbs is indicative of a notable loss in muscle performance at 9-13 months post-surgery. These results provide initial evidence for supporting further research examining the inclusion of hamstring endurance training in ACL rehabilitation programmes post-surgery.

Individual distribution of muscle hypertrophy among hamstring muscle heads: Adding muscle volume where you need is not so simple

PURPOSE

The aim of this study was to determine whether a 9-week resistance training program based on high load (HL) versus low load combined with blood flow restriction (LL-BFR) induced a similar (i) distribution of muscle hypertrophy among hamstring heads (semimembranosus, SM; semitendinosus, ST; and biceps femoris long head, BF) and (ii) magnitude of tendon hypertrophy of ST, using a parallel randomized controlled trial.

METHODS

A total of 45 participants were randomly allocated to one of three groups: HL, LL-BFR, and control (CON). Both HL and LL-BFR performed a 9-week resistance training program composed of seated leg curl and stiff-leg deadlift exercises. Freehand 3D ultrasound was used to assess the changes in muscle and tendon volume.

RESULTS

The increase in ST volume was greater in HL (26.5 ± 25.5%) compared to CON (p = 0.004). No difference was found between CON and LL-BFR for the ST muscle volume (p = 0.627). The change in SM muscle volume was greater for LL-BFR (21.6 ± 27.8%) compared to CON (p = 0.025). No difference was found between HL and CON for the SM muscle volume (p = 0.178).There was no change in BF muscle volume in LL-BFR (14.0 ± 16.5%; p = 0.436) compared to CON group. No difference was found between HL and CON for the BF muscle volume (p = 1.0). Regarding ST tendon volume, we did not report an effect of training regimens (p = 0.411).

CONCLUSION

These results provide evidence that the HL program induced a selective hypertrophy of the ST while LL-BFR induced hypertrophy of SM. The magnitude of the selective hypertrophy observed within each group varied greatly between individuals. This finding suggests that it is very difficult to early determine the location of the hypertrophy among a muscle group.

Validity and Reliability of 3-D Ultrasound Imaging to Measure Hamstring Muscle and Tendon Volumes

OBJECTIVE

The validity and reliability of 3-D ultrasound (US) in estimation of muscle and tendon volume was assessed in a very limited number of muscles that can be easily immersed. The objective of the present study was to assess the validity and reliability of muscle volume measurements for all hamstring muscle heads and gracilis (GR), as well as tendon volume for the semitendinosus (ST) and GR using freehand 3-D US.

METHODS

Three-dimensional US acquisitions were performed for 13 participants in two distinct sessions on separate days, in addition to one session dedicated to magnetic resonance imaging (MRI). Volumes of ST, semimembranosus (SM), biceps femoris short (BFsh) and long (BFlh) heads, and GR muscles and from the tendon from semitendinosus (STtd) and gracilis (GRtd) were collected.

RESULTS

The bias and the 95% confidence intervals of 3-D US compared with MRI ranged from -1.9 mL (-0.8%) to 1.2 mL (1.0%) for muscle volume and from 0.01 mL (0.2%) to -0.03 mL (-2.6%) for tendon volume. For muscle volume assessed using 3-D US, intraclass correlation coefficients (ICCs) ranged from 0.98 (GR) to 1.00, and coefficients of variation (CV) from 1.1% (SM) to 3.4% (BFsh). For tendon volume, ICCs were 0.99, and CVs between 3.2% (STtd) and 3.4% (GRtd).

CONCLUSION

Three-dimensional US can provide a valid and reliable inter-day measurement of hamstrings and GR for both muscle and tendon volumes. In the future, this technique could be used as an outcome for strengthening interventions and potentially in clinical environments.

Trajectories of Pain and Function Outcomes up to 5 to 8 Years Following Total Knee Arthroplasty

BACKGROUND

There appears to be substantial variability in outcomes > 2 years following total knee arthroplasty (TKA) that is masked by whole group analyses. The goal of the study was to identify trajectories of pain and function outcomes up to 5 to 8 years post-TKA and to identify baseline factors that are associated with different trajectories of recovery.

METHODS

Baseline, 6-month, and 12-month pain and function data were collected in a previous study investigating predictors of outcome following primary TKA (n = 286), along with a variety of baseline predictor variables. The present study obtained pain and function data at 5 to 8 years following TKA in the same cohort (n = 201). Latent class linear mixed models were used to identify different classes of pain and functional trajectories over time. The extent to which differences across latent classes were explained by baseline predictor variables was determined.

RESULTS

Three classes of pain and two classes of function trajectory were identified. While most patients (84% to 93%) followed a trajectory that showed an initial rapid gain following surgery that was sustained through 5 to 8 years, both pain and function included at least one trajectory class that showed a meaningful change after 12 months. No predictor variables were significantly associated with either the pain or function classes.

CONCLUSIONS

Most patients follow a traditional trajectory of recovery in knee pain and function over 5 to 8 years. However, alternative trajectories are observed in an important minority of patients such that knee pain and function at 12 months after surgery does not always reflect outcomes at 5 to 8 years.

A combination of high preoperative pain and low radiological grade of arthritis is associated with a greater intensity of persistent pain 12 months after total knee arthroplasty

Aims

Despite new technologies for total knee arthroplasty (TKA), approximately 20% of patients are dissatisfied. A major reason for dissatisfaction and revision surgery after TKA is persistent pain. The radiological grade of osteoarthritis (OA) preoperatively has been investigated as a predictor of the outcome after TKA, with conflicting results. The aim of this study was to determine if there is a difference in the intensity of pain 12 months after TKA in relation to the preoperative radiological grade of OA alone, and the combination of the intensity of preoperative pain and radiological grade of OA.

Methods

The preoperative data of 300 patients who underwent primary TKA were collected, including clinical information (age, sex, preoperative pain), psychological variables (depression, anxiety, pain catastrophizing, anticipated pain), and quantitative sensory testing (temporal summation, pressure pain thresholds, conditioned pain modulation). The preoperative radiological severity of OA was graded according to the Kellgren-Lawrence (KL) classification. Persistent pain in the knee was recorded 12 months postoperatively. Generalized linear models explored differences in postoperative pain according to the KL grade, and combined preoperative pain and KL grade. Relative risk models explored which preoperative variables were associated with the high preoperative pain/low KL grade group.

Results

Pain 12 months after TKA was not associated with the preoperative KL grade alone. Significantly increased pain 12 months after TKA was found in patients with a combination of high preoperative pain and a low KL grade (p = 0.012). Patients in this group were significantly more likely to be male, younger, and have higher preoperative pain catastrophizing, higher depression, and lower anxiety (all p ≤ 0.05).

Conclusion

Combined high preoperative pain and low radiological grade of OA, but not the radiological grade alone, was associated with a higher intensity of pain 12 months after primary TKA. This group may have a more complex cause of pain that requires additional psychological interventions in order to optimize the outcome of TKA. Cite this article: Bone Joint J 2022;104-B(11):1202–1208.

A Prospective, Median 15-Year Comparison of Ponseti Casting and Surgical Treatment of Clubfoot

BACKGROUND

In 2010, 2 authors of this current study reported the results of Ponseti treatment compared with primary posteromedial release (PMR) for congenital talipes equinovarus in a cohort of 51 prospective patients. This current study shows outcomes recorded at a median of 15 years after the original treatment.

METHODS

Patient health records were available for all 51 patients at a median of 15 years (range, 13 to 17 years) following treatment of congenital talipes equinovarus with either the Ponseti method (25 patients [38 feet]) or PMR (26 patients [42 feet]). Thirty-eight of 51 patients could be contacted, and 33 patients (65%) participated in the clinical review, comprising patient-reported outcomes, clinical examination, 3-dimensional gait analysis, and plantar pressures.

RESULTS

Sixteen (42%) of 38 Ponseti-treated feet and 20 (48%) of 42 PMR-treated feet had undergone a further surgical procedure. The PMR-treated feet were more likely to undergo osteotomies and intra-articular surgical procedures (15 feet) than the Ponseti-treated feet (5 feet) (p < 0.05). Of the 33 patients reviewed with multimodal assessment, the Ponseti group, compared with the PMR group, demonstrated better Dimeglio scores (5.8 compared with 7.0 points; p < 0.05), Disease Specific Instrument (80.7 compared with 65.6 points; p < 0.05), Functional Disability Inventory (1.1 compared with 5.1; p < 0.05), and American Academy of Orthopaedic Surgeons (AAOS) Foot and Ankle Outcomes Questionnaire scores (52.2 compared with 46.6 points; p < 0.05), as well as improved total sagittal ankle range of motion in gait and ankle plantar flexion range at toe-off. The PMR group with clinical hindfoot varus displayed higher pressures in the lateral midfoot and the forefoot.

CONCLUSIONS

Although the numbers of repeat surgical interventions following Ponseti treatment and primary PMR were similar, the PMR-treated feet had greater numbers of osteotomies and intra-articular surgical procedures. Functional outcomes were improved at a median of 15 years for feet treated with the Ponseti method compared with feet treated with PMR, with advantages seen in the Ponseti group over several domains. This study provides the most comprehensive evaluation of outcomes close to skeletal maturity in prospective cohorts, reinforcing the Ponseti method as the initial treatment of choice for idiopathic clubfeet.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Experimental Hand and Knee Pain Cause Differential Effects on Corticomotor Excitability

Acute pain elicits a well-known inhibitory effect on upper limb corticomotor excitability, whereas the temporal effects of lower-limb experimental pain and pain in a remote limb are less clear. The aim of this study was to compare the temporal corticomotor excitability changes in the upper and lower limbs in response to acute upper and lower limb pain. In a cross-over design, 13 participants (age 29 ± 9 years; 12 male) attended 2 sessions where experimental pain was induced by injecting hypertonic saline into either the first dorsal interosseous (FDI) muscle or infrapatellar fat pad at the knee, inducing a short-lasting pain experience scored on a numerical rating scale (NRS). Motor evoked potentials (MEPs) in response to transcranial magnetic stimulation were recorded in the FDI and vastus lateralis (VL) muscles before, during, and following pain. Hand and knee pain NRS scores were not significantly different. Hand pain elicited a short duration inhibition of the FDI MEPs (P < .0001) together with a facilitation of VL MEPs (P = .001) that outlasted the duration of pain. Knee pain elicited a short-duration facilitation of VL MEPs (P = .003) with no significant effect in the FDI MEPs (P = .46). The findings indicate a limb-specific corticomotor response to experimental pain that may be related to limb function. PERSPECTIVE: These data demonstrate the impact of acute, experimental pain on corticomotor excitability in the upper and lower limbs. This facilitates our understanding of the effect of pain on motor control of both local and distant muscles.

A Gel Pad Designed to Measure Muscle Volume Using Freehand 3-Dimensional Ultrasonography

We developed an innovative gel pad that covers the entire lower leg to remove artifacts due to the pressure of the transducer in freehand 3-dimensional ultrasonography. In comparison to the reference method in water, this study showed that this new method was valid (bias, 3.4 mL; limit of agreement, 7.7 mL for a volume of ≈220 mL) and reliable (coefficient of variation, <1.1%) for the measurement of gastrocnemius medialis muscle volume. Considering that it is easier to use than the water tank technique, it has much promise for volumetric measurement of many muscles.

Steroids to reduce the impact on delirium (STRIDE): a double-blind, randomised, placebo-controlled feasibility trial of pre-operative dexamethasone in people with hip fracture

Neuro-inflammation may be important in the pathogenesis of postoperative delirium following hip fracture surgery. Studies have suggested a potential role for steroids in reducing postoperative delirium; however, the potential efficacy and safety of pre-operative high-dose dexamethasone in this specific population is largely unknown. Conducting such a study could be challenging, considering the multidisciplinary team involvement and the emergency nature of the surgery. The aim of this study was to assess feasibility and effectiveness of dexamethasone given as early as possible following hospital admission for hip fracture, to inform whether a full-scale trial is warranted. This single-centre, randomised, double-blind, placebo-controlled study randomly allocated 79 participants undergoing hip fracture surgery to dexamethasone 20 mg or placebo pre-operatively. Eligibility and recruitment rates, timing of the intervention and adverse events were recorded. Incidence and severity of postoperative delirium were assessed using the 4AT delirium screening tool and the Memorial Delirium Assessment Scale. Postoperative pain, length of stay and mortality were also assessed. The eligibility rate for inclusion was 178/527 (34%), and 57/178 (32%) of eligible patients presented to hospital when no researcher was available (e.g. after-hours, weekends, public holidays). Recruitment was limited mainly by ethical limitations (not including patients with impaired cognition) and lack of weekend staffing. Median (IQR [range]) time from emergency department admission to drug administration was 13.3 (5.9-17.6 [1.8-139.6]) hours. There was a significant difference in delirium severity scores, favouring the dexamethasone group: median (IQR [range]) 5 (3-6 [3-7]) vs. 9 (6-13 [5-14]) in the placebo group, with the probability of superiority effect size being 0.89, p = 0.010. Delirium incidence did not differ between groups: 6/40 (15%) in the dexamethasone group vs. 9/39 (23%) in the placebo group, relative risk (95%CI) 0.65 (0.22-1.65), p = 0.360). A larger randomised controlled trial is feasible and ideally this should include people with existing cognitive impairment, seven days-a-week cover and a multicentre design.

A Higher Grey Matter Density in the Amygdala and Midbrain Is Associated with Persistent Pain Following Total Knee Arthroplasty

Objective

The development of persistent pain following total knee arthroplasty (TKA) is common, but its underlying mechanisms are unknown. The goal of the study was to assess brain grey matter structure and its correlation with function of the nociceptive system in people with good and poor outcomes following TKA.

Subjects

Thirty-one people with LOW_PAIN (&lt;3/10 on the numerical ratings scale [NRS]) at six months following TKA and 15 people with HIGH_PAIN (≥3/10 on the NRS) were recruited into the study.

Methods

Grey matter in key brain areas related to nociception was analyzed using voxel-based morphometry (VBM). Nociceptive facilitatory and inhibitory processes were evaluated using quantitative sensory testing (QST). QST scores and grey matter density in prespecified brain regions were compared between the LOW_PAIN and HIGH_PAIN groups. Regression analyses were used to analyze the associations between the grey matter and QST scores.

Results

There were no between-group differences in QST measures. In the VBM analysis, the HIGH_PAIN group had a higher grey matter density in the right amygdala, right nucleus accumbens, and in the periaqueductal grey (PAG), but lower grey matter density in the dorsal part of the left caudate nucleus. Grey matter density in the right amygdala and PAG correlated positively with temporal summation of pain.

Conclusions

Persistent pain at six months after TKA is associated with a higher grey matter density in the regions involved in central sensitization and pain-related fear, which may contribute to the development of persistent pain after surgery.

Stretch reflex changes in ACL-deficient individuals and healthy controls during normal and surprise landings

No studies in ACL-D individuals have examined neuromuscular adaptations during landing from a jump where an unexpected mechanical event changes the pre-programmed course of movement. The purpose of this study was to compare pre- and post-landing muscle activation in ACL-D individuals and uninjured controls during normal and surprise landings. Nineteen ACL-D and 17 uninjured volunteered. Participants performed repeated single leg landings from 30 and 15 cm heights. During 15 cm landings, a single surprise landing was performed where participants unexpectedly fell through a false surface at 15 cm to the solid floor a further 15 cm below. Electromyography (EMG) amplitude from vastus lateralis (VL), lateral hamstrings (LH), and soleus (Sol) was recorded. Pre-landing (-60 to 0 ms), post-landing short latency (31-60 ms), and post-landing medium latency (61-90 ms) periods were examined. Comparisons in EMG amplitudes were made across limbs (ACL-D, ACL intact, and control) in 30 cm landings. Additionally, the ratio of EMG amplitude in surprise:30 cm normal landings was analyzed. Post-landing LH EMG was reduced in the ACL-D compared to control limbs at short latencies (P < 0.05). Post-landing VL EMG was reduced in the ACL-D and ACL intact compared to the control limb at both latencies (P < 0.05). Surprise landings notably increased post-landing EMG in all muscles, across all limbs (P < 0.001). However, the gain in VL EMG was significantly greater in ACL-D and ACL intact limbs (P < 0.05). These changes in neuromuscular control of ACL-D individuals during expected and surprise landings may have important implications for rehabilitation, instability, and the risk of secondary injury.

Chronic effects of muscle and nerve-directed stretching on tissue mechanics

Tissue-directed stretching interventions can preferentially load muscular or nonmuscular structures such as peripheral nerves. How these tissues adapt mechanically to long-term stretching is poorly understood. This randomized, single-blind, controlled study used ultrasonography and dynamometry to compare the effects of 12-wk nerve-directed and muscle-directed stretching programs versus control on maximal ankle dorsiflexion range of motion (ROM) and passive torque, shear wave velocity (SWV; an index of stiffness), and architecture of triceps surae and sciatic nerve. Sixty healthy adults were randomized to receive nerve-directed stretching, muscle-directed stretching, or no intervention (control). The muscle-directed protocol was designed to primarily stretch the plantar flexor muscle group, whereas the nerve-directed intervention targeted the sciatic nerve tract. Compared with the control group [mean; 95% confidence interval (CI)], muscle-directed intervention showed increased ROM (+7.3°; 95% CI: 4.1-10.5), decreased SWV of triceps surae (varied from -0.8 to -2.3 m/s across muscles), decreased passive torque (-6.8 N·m; 95% CI: -11.9 to -1.7), and greater gastrocnemius medialis fascicle length (+0.4 cm; 95% CI: 0.1-0.8). Muscle-directed intervention did not affect the SWV and size of sciatic nerve. Participants in the nerve-directed group showed a significant increase in ROM (+9.9°; 95% CI: 6.2-13.6) and a significant decrease in sciatic nerve SWV (> -1.8 m/s across nerve regions) compared with the control group. Nerve-directed intervention had no effect on the main outcomes at muscle and joint levels. These findings provide new insights into the long-term mechanical effects of stretching interventions and have relevance to clinical conditions where change in mechanical properties has occurred.NEW & NOTEWORTHY This study demonstrates that the mechanical properties of plantar flexor muscles and sciatic nerve can adapt mechanically to long-term stretching programs. Although interventions targeting muscular or nonmuscular structures are both effective at increasing maximal range of motion, the changes in tissue mechanical properties (stiffness) are specific to the structure being preferentially stretched by each program. We provide the first in vivo evidence that stiffness of peripheral nerves adapts to long-term loading stimuli using appropriate nerve-directed stretching.

Structural Brain Alterations Before and After Total Knee Arthroplasty: A Longitudinal Assessment

Objective

Many studies have provided evidence of altered brain structure in chronic pain conditions, as well as further adaptations following treatment that are coincident with changes in pain. Less is known regarding how these structural brain adaptations relate to assessments of nociceptive processing. The current study aimed to investigate brain structure in people with knee osteoarthritis (OA) before and after total knee arthroplasty (TKA) and to investigate the relationships between these findings and quantitative sensory testing (QST) of the nociceptive system.

Methods

Twenty-nine people with knee OA underwent magnetic resonance imaging (MRI) scans and QST before and six months after TKA and were compared with a pain-free control group (N = 18). MRI analyses involved voxel-based morphometry and fractional anisotropy.

Results

Before TKA, there was reduced gray matter volume and impaired fractional anisotropy in areas associated with nociceptive processing, with further gray matter adaptations and improvements in fractional anisotropy evident after TKA. QST revealed increased nociceptive facilitation and impaired inhibition in knee OA that was reversed after TKA. There were minimal relationships found between MRI data and QST assessments or pain report.

Conclusions

In people with end-stage knee OA, region-specific gray matter atrophy was detected, with further changes in gray matter volume and improvements in white matter integrity observed after joint replacement. Despite coincident alterations in nociceptive inhibition and facilitation processes, there did not appear to be any association between these functional assessments of the nociceptive system and changes in brain structure.

Effects of stroke injury on the shear modulus of the lower leg muscle during passive dorsiflexion

Contractures are common complications of a stroke. The spatial location of the increased stiffness among plantar flexors and its variability among survivors remain unknown. This study assessed the mechanical properties of the lower leg muscles in stroke survivors during passive dorsiflexions. Stiffness was estimated through the measurement of the shear modulus. Two experiments were independently conducted, in which participants lay supine: with the knee extended ( experiment 1, n = 13 stroke survivors and n = 13 controls), or with the knee flexed at 90° ( experiment 2, n = 14 stroke survivors and n = 14 controls). The shear modulus of plantar flexors [gastrocnemius medialis (three locations), gastrocnemius lateralis (three locations), soleus (two locations), flexor digitorum longus, flexor hallucis longus), peroneus longus] and dorsiflexors (tibialis anterior and extensor digitorum longus) was measured using ultrasound shear wave elastography during passive dorsiflexions (2°/s). At the same ankle angle, stroke survivors displayed higher shear modulus than controls for gastrocnemius medialis and gastrocnemius lateralis (knee extended) and soleus (knee flexed). Very low shear modulus was found for the other muscles. The adjustment for muscle slack angle suggested that the increased shear modulus was arising from consequences of contractures. The stiffness distribution between muscles was consistent across participants with the highest shear modulus reported for the most distal regions of gastrocnemius medialis (knee extended) and soleus (knee flexed). These results provide a better appreciation of stiffness locations among plantar flexors of stroke survivors and can provide evidence for the implementation of clinical trials to evaluate targeted interventions applied on these specific muscle regions.

NEW & NOTEWORTHY The shear modulus of 13 muscle regions was assessed in stroke patients using elastography. When compared with controls, shear modulus was increased in the gastrocnemius muscle (GM) when the knee was extended and in the soleus (SOL) when the knee was flexed. The distal regions of GM and SOL were the most affected. These changes were consistent in all the stroke patients, suggesting that the regions are a potential source of the increase in joint stiffness.

Non-Muscular Structures Can Limit the Maximal Joint Range of Motion during Stretching

Stretching is widely used in sport training and clinical practice with the aim of increasing muscle-tendon extensibility and joint range of motion. The underlying assumption is that extensibility increases as a result of increased passive tension applied to muscle-tendon units. In some stretching protocols, this condition is not always met sufficiently to trigger adaptation within the muscle-tendon unit. For example, there is experimental evidence that both acute and chronic stretching interventions may increase the maximal range of motion in the absence of changes in the passive torque-angle curve. We contend that these results are partly explained by the influence of non-muscular structures that contribute only marginally to the passive torque. The potential candidates are the nervous system and fasciae, which would play an important role in the perception of the stretch and in the limitation of the range of motion of the maximal joints. At least in part, this may explain the lack of a significant effect of some chronic stretching interventions to change passive muscle tension.

Pain Catastrophizing is Not Associated With Spinal Nociceptive Processing in People With Chronic Widespread Pain

Objectives:

Pain catastrophizing has been associated with higher pain intensity, increased risk of developing chronic pain and poorer outcomes after treatment. Despite this, the mechanisms by which pain catastrophizing influences pain remain poorly understood. It has been hypothesized that pain catastrophizing may impair descending inhibition of spinal level nociception. The aims of this study were to compare spinal nociceptive processing in people with chronic widespread pain and pain-free controls and examine potential relationships between measures of pain catastrophizing and spinal nociception.

Materials and Methods:

Twenty-six patients with chronic widespread pain and 22 pain-free individuals participated in this study. Spinal nociception was measured using the nociceptive flexion reflex (NFR) threshold and NFR inhibition, measured as the change in NFR area during exposure to a second, painful conditioning stimulus (cold water immersion). Pain catastrophizing was assessed using the Pain Catastrophizing Scale and a situational pain catastrophizing scale.

Results:

Compared with pain-free controls, patients with chronic widespread pain had higher pain catastrophizing scores and lower NFR thresholds. Although NFR area was reduced by a painful conditioning stimulus in controls, this was not apparent in individuals with chronic widespread pain. No significant correlations were observed between measures of pain catastrophizing and spinal nociception.

Discussion:

Despite increased excitability and decreased inhibition of spinal nociception in patients with chronic widespread pain, we could find no evidence of a significant relationship between pain catastrophizing and measures of spinal nociceptive processing.

TENS Alleviates Muscle Weakness Attributable to Attenuation of Ia Afferents

Quadriceps weakness is a notable problem following knee damage. Research has shown effectiveness of TENS in improving Quadriceps weakness associated with arthrogenic muscle inhibition. However, these studies were not focused upon short term delivery of TENS, nor did they examine the potential mechanism(s). The present study examined the effect of 25-30 s of TENS upon weakness induced temporarily by a prolonged vibration. Subjects performed eccentric MVCs under 2 conditions (TENS and no-TENS). First, MVC was measured at baseline. For the TENS condition, TENS was applied to each subject's knee joint during a second MVC measurement after vibration. For no-TENS condition, TENS was not applied during the 2^nd MVC measurement. MVC between pre-and post-vibration stimulation were compared across the 2 conditions. The results showed that MVC and EMG of TENS-condition was larger than that of no-TENS condition. Our results suggest that TENS could partially restore α-motoneuron activation, despite the induced dysfunctional γ-loop. These results suggest that mechanisms independent of the γ-loop such as a direct facilitation of the QF α-motoneuron pool by a long latency spinal-reflex and/or supraspinal mechanisms appear more likely to be responsible. The findings provide further support for utilizing TENS, even when γ-loop dysfunction is present following joint damage.

Diagnostic Accuracy of Clinical Examination and Imaging Findings for Identifying Subacromial Pain

BACKGROUND

The diagnosis of subacromial pathology is limited by the poor accuracy of clinical tests for specific pathologies. The aim of this study was to estimate the diagnostic accuracy of clinical examination and imaging features for identifying subacromial pain (SAP) defined by a positive response to diagnostic injection, and to evaluate the influence of imaging findings on the clinical diagnosis of SAP.

METHODS AND FINDINGS

In a prospective, diagnostic accuracy design, 208 consecutive patients presenting to their primary healthcare practitioner for the first time with a new episode of shoulder pain were recruited. All participants underwent a standardized clinical examination, shoulder x-ray series and diagnostic ultrasound scan. Results were compared with the response to a diagnostic block of xylocaineTM injected into the SAB under ultrasound guidance using ≥80% post-injection reduction in pain intensity as the positive anaesthetic response (PAR) criterion. Diagnostic accuracy statistics were calculated for combinations of clinical and imaging variables demonstrating the highest likelihood of a PAR. A PAR was reported by 34% of participants. In participants with no loss of passive external rotation, combinations of three clinical variables (anterior shoulder pain, strain injury, absence of symptoms at end-range external rotation (in abduction)) demonstrated 100% specificity for a PAR when all three were positive (LR+ infinity; 95%CI 2.9, infinity). A full-thickness supraspinatus tear on ultrasound increased the likelihood of a PAR irrespective of age (specificity 98% (95%CI 94, 100); LR+ 6.2; 95% CI 1.5, 25.7)). Imaging did not improve the ability to rule-out a PAR.

CONCLUSION

Combinations of clinical examination findings and a full-thickness supraspinatus tear on ultrasound scan can help confirm, but not exclude, the presence of subacromial pain. Other imaging findings were of limited value for diagnosing SAP.

Experimental knee pain impairs submaximal force steadiness in isometric, eccentric, and concentric muscle actions

INTRODUCTION

Populations with knee joint damage, including arthritis, have noted impairments in the regulation of submaximal muscle force. It is difficult to determine the exact cause of such impairments given the joint pathology and associated neuromuscular adaptations. Experimental pain models that have been used to isolate the effects of pain on muscle force regulation have shown impaired force steadiness during acute pain. However, few studies have examined force regulation during dynamic contractions, and these findings have been inconsistent. The goal of the current study was to examine the effect of experimental knee joint pain on submaximal quadriceps force regulation during isometric and dynamic contractions.

METHODS

The study involved fifteen healthy participants. Participants were seated in an isokinetic dynamometer. Knee extensor force matching tasks were completed in isometric, eccentric, and concentric muscle contraction conditions. The target force was set to 10 % of maximum for each contraction type. Hypertonic saline was then injected into the infrapatella fat pad to generate acute joint pain. The force matching tasks were repeated during pain and once more 5 min after pain had subsided.

RESULTS

Hypertonic saline resulted in knee pain with an average peak pain rating of 5.5 ± 2.1 (0-10 scale) that lasted for 18 ± 4 mins. Force steadiness significantly reduced during pain across all three muscle contraction conditions. There was a trend to increased force matching error during pain but this was not significant.

CONCLUSION

Experimental knee pain leads to impaired quadriceps force steadiness during isometric, eccentric, and concentric contractions, providing further evidence that joint pain directly affects motor performance. Given the established relationship between submaximal muscle force steadiness and function, such an effect may be detrimental to the performance of tasks in daily life. In order to restore motor performance in people with painful arthritic conditions of the knee, it may be important to first manage their pain more effectively.

Predictors of persistent pain after total knee arthroplasty: a systematic review and meta-analysis

BACKGROUND

Several studies have identified clinical, psychosocial, patient characteristic, and perioperative variables that are associated with persistent postsurgical pain; however, the relative effect of these variables has yet to be quantified. The aim of the study was to provide a systematic review and meta-analysis of predictor variables associated with persistent pain after total knee arthroplasty (TKA).

METHODS

Included studies were required to measure predictor variables prior to or at the time of surgery, include a pain outcome measure at least 3 months post-TKA, and include a statistical analysis of the effect of the predictor variable(s) on the outcome measure. Counts were undertaken of the number of times each predictor was analysed and the number of times it was found to have a significant relationship with persistent pain. Separate meta-analyses were performed to determine the effect size of each predictor on persistent pain. Outcomes from studies implementing uni- and multivariable statistical models were analysed separately.

RESULTS

Thirty-two studies involving almost 30 000 patients were included in the review. Preoperative pain was the predictor that most commonly demonstrated a significant relationship with persistent pain across uni- and multivariable analyses. In the meta-analyses of data from univariate models, the largest effect sizes were found for: other pain sites, catastrophizing, and depression. For data from multivariate models, significant effects were evident for: catastrophizing, preoperative pain, mental health, and comorbidities.

CONCLUSIONS

Catastrophizing, mental health, preoperative knee pain, and pain at other sites are the strongest independent predictors of persistent pain after TKA.

Optimizing muscle power after stroke: a cross-sectional study

Background

Stroke remains a leading cause of disability worldwide and results in muscle performance deficits and limitations in activity performance. Rehabilitation aims to address muscle dysfunction in an effort to improve activity and participation. While muscle strength has an impact on activity performance, muscle power has recently been acknowledged as contributing significantly to activity performance in this population. Therefore, rehabilitation efforts should include training of muscle power. However, little is known about what training parameters, or load, optimize muscle power performance in people with stroke. The purpose of this study was to investigate lower limb muscle power performance at differing loads in people with and without stroke.

Methods

A cross-sectional study design investigated muscle power performance in 58 hemiplegic and age matched control participants. Lower limb muscle power was measured using a modified leg press machine at 30, 50 and 70% of one repetition maximum (1-RM) strength.

Results

There were significant differences in peak power between involved and uninvolved limbs of stroke participants and between uninvolved and control limbs. Peak power was greatest when pushing against a load of 30% of 1RM for involved, uninvolved and control limbs. Involved limb peak power irrespective of load (Mean:220 ± SD:134 W) was significantly lower (p < 0.05) than the uninvolved limb (Mean:466 ± SD:220 W). Both the involved and uninvolved limbs generated significantly lower peak power (p < 0.05) than the control limb (Mean:708 ± SD:289 W).

Conclusions

Significant power deficits were seen in both the involved and uninvolved limbs after stroke. Maximal muscle power was produced when pushing against lighter loads. Further intervention studies are needed to determine whether training of both limbs at lighter loads (and higher velocities) are preferable to improve both power and activity performance after stroke.

A method to monitor upper limb movement direction encoding in the corticomotor pathway

Abnormal shoulder and elbow muscle coactivation patterns, or muscle synergies, are commonly present following stroke and may arise through dysfunctional descending neural control from the cortex. The authors evaluated a novel technique for examining corticomotor movement encoding of the upper limb in three dimensions. A 6-degree-of-freedom loadcell recorded arm twitch responses in healthy adults following stimulation over the cortex or over Erb's point in the periphery. Stimuli were delivered while the arm generated a 5 N preload in each of the 6 axial directions. The initial force twitch response to stimulation was used to construct twitch direction vectors for each preload direction. General linear mixed model analyses were used to determine the influence of stimulation location, preload direction, posture, and stimulation intensity on twitch direction. Cortical stimulation gave rise to arm twitch responses that were predictably modified by preload direction. Peripheral stimulation elicited stereotypical twitches that were not influenced by preload. Our stimulation, recording, and analysis techniques were able to capture movement encoding of the upper limb in three dimensions. Such techniques could be utilized in the stroke population to determine and monitor the presence of upper limb synergies during muscle activation.

Gender differences in both active and passive parts of the plantar flexors series elastic component stiffness and geometrical parameters of the muscle-tendon complex

Men are reportedly at higher risk of plantar flexor muscle injury and Achilles tendon ruptures than women. Biomechanical parameters are thought to play a role in the higher frequency of injury to males. One parameter is the stiffness of tissues; a stiff tissue cannot absorb sufficient energy with loading, and subsequently may be more likely to be injured. Thus, our purpose was to investigate the gender difference in the geometrical parameters of plantar flexor's muscle-tendon complex and the stiffness of both active and passive parts of the series elastic component (S(SEC1) and S(SEC2) , respectively). Using the alpha method on data obtained from quick stretches to the plantar flexors performed during isometric contractions, S(SEC1) and S(SEC2) were assessed. Plantar flexor muscles and Achilles tendon cross-sectional areas (CSA(TS) and CSA(AT) , respectively) were determined in young healthy men (n = 49) and women (n = 31). The findings showed that S(SEC2) was higher in men (p < 0.001), but this difference was not apparent when S(SEC2) was normalized to CSA(AT) (p > 0.05). In contrast, S(SEC1) was lower in men (p < 0.001) and remained so after normalization to CSA(TS) . Higher joint stiffness observed in men was notably influenced by lever arm length. Thus, the results of this study have implications for performance and injury.

Evaluating intratester reliability of manual masking of plantar pressure measurements associated with chronic gout

BACKGROUND

Plantar pressure measurements are commonly used to evaluate foot function in chronic musculoskeletal conditions. However, manually identifying anatomical landmarks is a source of measurement error and can produce unreliable data. The aim of this study was to evaluate intratester reliability associated with manual masking of plantar pressure measurements in patients with gout.

METHODS

Twenty-five patients with chronic gout (mean disease duration, 22 years) were recruited from rheumatology outpatient clinics. Patients were excluded if they were experiencing an acute gout flare at the time of assessment, had lower-limb amputation, or had diabetes mellitus. Manual masking of peak plantar pressures and pressure-time integrals under ten regions of the foot were undertaken on two occasions on the same day using an in-shoe pressure measurement system. Test-retest reliability was assessed by using intraclass correlation coefficients, SEM, 95% limits of agreement, and minimal detectable change.

RESULTS

Mean peak pressure intraclass correlation coefficients ranged from 0.92 to 0.97, with SEM of 8% to 14%. The 95% limits of agreement ranged from-150.3 to 133.5 kPa, and the minimal detectable change ranged from 30.8 to 80.6 kPa. For pressure-time integrals, intraclass correlation coefficients were 0.86 to 0.94, and SEM were 5% to 29%, with the greater errors observed under the toes. The 95% limits of agreement ranged from -48.5 to 48.8 kPa/sec, and the minimal detectable change ranged from 6.8 to 21.0 kPa/sec.

CONCLUSIONS

These findings provide clinicians with information confirming the errors associated with manual masking of plantar pressure measurements in patients with gout.

Insights from a physiotherapist's lived experience of osteoarthritis

Osteoarthritis (OA) of a hip joint, with subsequent total hip joint replacement surgery, is portrayed in the literature in terms of quantitative research studies, where the person living with the hip disappears in objective statistical analyses, or in qualitative studies where one person's story is fragmented within thematic findings. This phenomenological study of a physiotherapist's (Peter) lived experience of OA offers insights relevant to practice. In the initial stages of the disease, Peter was too close to 'see' the possibility of OA as a diagnosis. As the pain limited what he could do, he needed to reinvent ways of retaining his sense of 'self'. The pain worsened; there was nothing that relieved it. The experience became one of endurance, leading to a moment when he decided the time had come to have surgery. Post-surgery, the journey of recovery was one of the feelings vulnerable. He wanted guidance and re-assurance. Paradoxically, recovery showed itself as 'forgetting' the body. The insights call for therapists to listen to the experience of clients and be alongside side them as they struggle with vulnerability. Sharing an understanding of the nature of the experience can bring confidence to clients.

Mechanisms of quadriceps muscle weakness in knee joint osteoarthritis: the effects of prolonged vibration on torque and muscle activation in osteoarthritic and healthy control subjects

INTRODUCTION

A consequence of knee joint osteoarthritis (OA) is an inability to fully activate the quadriceps muscles, a problem termed arthrogenic muscle inhibition (AMI). AMI leads to marked quadriceps weakness that impairs physical function and may hasten disease progression. The purpose of the present study was to determine whether γ-loop dysfunction contributes to AMI in people with knee joint OA.

METHODS

Fifteen subjects with knee joint OA and 15 controls with no history of knee joint pathology participated in this study. Quadriceps and hamstrings peak isometric torque (Nm) and electromyography (EMG) amplitude were collected before and after 20 minutes of 50 Hz vibration applied to the infrapatellar tendon. Between-group differences in pre-vibration torque were analysed using a one-way analysis of covariance, with age, gender and body mass (kg) as the covariates. If the γ-loop is intact, vibration should decrease torque and EMG levels in the target muscle; if dysfunctional, then torque and EMG levels should not change following vibration. One-sample t tests were thus undertaken to analyse whether percentage changes in torque and EMG differed from zero after vibration in each group. In addition, analyses of covariance were utilised to analyse between-group differences in the percentage changes in torque and EMG following vibration.

RESULTS

Pre-vibration quadriceps torque was significantly lower in the OA group compared with the control group (P = 0.005). Following tendon vibration, quadriceps torque (P < 0.001) and EMG amplitude (P ≤0.001) decreased significantly in the control group but did not change in the OA group (all P > 0.299). Hamstrings torque and EMG amplitude were unchanged in both groups (all P > 0.204). The vibration-induced changes in quadriceps torque and EMG were significantly different between the OA and control groups (all P < 0.011). No between-group differences were observed for the change in hamstrings torque or EMG (all P > 0.554).

CONCLUSIONS

γ-loop dysfunction may contribute to AMI in individuals with knee joint OA, partially explaining the marked quadriceps weakness and atrophy that is often observed in this population.

A prospective study of shoulder pain in primary care: prevalence of imaged pathology and response to guided diagnostic blocks

BACKGROUND

The prevalence of imaged pathology in primary care has received little attention and the relevance of identified pathology to symptoms remains unclear. This paper reports the prevalence of imaged pathology and the association between pathology and response to diagnostic blocks into the subacromial bursa (SAB), acromioclavicular joint (ACJ) and glenohumeral joint (GHJ).

METHODS

Consecutive patients with shoulder pain recruited from primary care underwent standardised x-ray, diagnostic ultrasound scan and diagnostic injections of local anaesthetic into the SAB and ACJ. Subjects who reported less than 80% reduction in pain following either of these injections were referred for a magnetic resonance arthrogram (MRA) and GHJ diagnostic block. Differences in proportions of positive and negative imaging findings in the anaesthetic response groups were assessed using Fishers test and odds ratios were calculated a for positive anaesthetic response (PAR) to diagnostic blocks.

RESULTS

In the 208 subjects recruited, the rotator cuff and SAB displayed the highest prevalence of pathology on both ultrasound (50% and 31% respectively) and MRA (65% and 76% respectively). The prevalence of PAR following SAB injection was 34% and ACJ injection 14%. Of the 59% reporting a negative anaesthetic response (NAR) for both of these injections, 16% demonstrated a PAR to GHJ injection. A full thickness tear of supraspinatus on ultrasound was associated with PAR to SAB injection (OR 5.02; p < 0.05). Ultrasound evidence of a biceps tendon sheath effusion (OR 8.0; p < 0.01) and an intact rotator cuff (OR 1.3; p < 0.05) were associated with PAR to GHJ injection. No imaging findings were strongly associated with PAR to ACJ injection (p ≤ 0.05).

CONCLUSIONS

Rotator cuff and SAB pathology were the most common findings on ultrasound and MRA. Evidence of a full thickness supraspinatus tear was associated with symptoms arising from the subacromial region, and a biceps tendon sheath effusion and an intact rotator cuff were associated with an intra-articular GHJ pain source. When combined with clinical information, these results may help guide diagnostic decision making in primary care.

Ankle sprains: patient perceptions of function and performance of physical tasks. A mixed methods approach

PURPOSE

To investigate patient's perceptions of function and performance of physical tasks after discharge from treatment for an ankle sprain.

METHODS

Using a mixed methods approach, 40 participants who presented with an acute sprained ankle and their treating clinicians completed two questionnaires related to function at the start and end of a rehabilitation programme. Additionally, participants completed the questionnaires at 6 weeks following discharge at which time they also performed physical tasks that were still perceived as difficult. Ten participants also completed a semi-structured interview.

RESULTS

There were no significant differences (p > 0.05) in the participant's and clinician's initial assessment of function. However, at discharge participants scored their function significantly (p < 0.05) lower than clinicians. This difference was not apparent 6 weeks later (p > 0.05). However, there was a significant difference (p  < 0.05) following actual performance of tasks with an effect size of 1.58. Participant interviews confirmed that patients had a fear of re-injury until they actually performed tasks that were perceived as difficult.

CONCLUSIONS

Clinicians and participants do not have a similar perception of the recovery of an ankle sprain at discharge. Performing tasks which were perceived as difficult were valuable in assisting participants gain an improved appreciation of their function.

Responsiveness, minimal importance difference and minimal detectable change scores of the shortened disability arm shoulder hand (QuickDASH) questionnaire

The aim of this study was to determine the responsiveness, Minimal Important Difference (MID) and Minimal Detectable Change (MDC) scores of the shortened Disability Arm Shoulder Hand (QuickDASH) questionnaire. Participants (n = 35) were recruited from private physiotherapy practices. Participants completed the QuickDASH questionnaire on two occasions; the first prior to treatment and the second at discharge or at six weeks post baseline, whichever event occurred first. The participants also completed a Global Change in Status Questionnaire (GSCQ). Responsiveness across treatment to discharge or at six weeks post initial visit was analysed by calculating the Effect Size (ES) and Standardised Response Mean (SRM). The MID was calculated using an anchor based approach and the MDC score was based upon calculations of the standard error of measurement (SEM). The results indicated that responsiveness was high (ES = 1.02, SRM = 1.1). The MID was 19 points while the MDC was 11 points. These results provide evidence that the QuickDASH is a responsive instrument when utilised in patients seen in private practice over a typical treatment interval.

Muscle inhibition following tendon stimulation is reduced in chronic stroke

OBJECTIVE

Electrical tendon stimulation elicits reflex inhibition in the homonymous muscle that is thought to be mediated by group III afferents. The study goals were to: evaluate group III-mediated reflex inhibition in people with post-stroke hemiparesis; determine the presence of heteronymous group III pathways; investigate the relevance of reflex inhibition to arm function.

METHODS

Reflex responses were recorded in wrist, elbow, and shoulder muscles following stimulation of the extensor carpi radialis (ECR) tendon in 16 people with post-stroke hemiparesis and 16 control subjects. In control subjects, reflex inhibition also was compared between static and dynamic muscle activation.

RESULTS

Reflex inhibition following ECR tendon stimulation was present in heteronymous muscles of most, but not all, stroke and control subjects. The level of reflex inhibition was significantly reduced in stroke subjects. In the controls, reflex inhibition was greater during dynamic activation of elbow muscles compared to static activation.

CONCLUSIONS

Evidence that reflex inhibition projects to heteronymous muscles and is modulated during movement suggests a role for the reflex in multi-joint coordination. The reflex is impaired in post-stroke hemiparesis.

SIGNIFICANCE

Abnormalities in the regulation of group III-mediated muscle inhibition in the stroke population may contribute to impaired muscle activation patterns during movement.

Exercise therapy for the management of osteoarthritis of the hip joint: a systematic review

INTRODUCTION

Recent guidelines pertaining to exercise for individuals with osteoarthritis have been released. These guidelines have been based primarily on studies of knee-joint osteoarthritis. The current study was focused on the hip joint, which has different biomechanical features and risk factors for osteoarthritis and has received much less attention in the literature. The purpose was to conduct a systematic review of the literature to evaluate the exercise programs used in intervention studies focused solely on hip-joint osteoarthritis, to decide whether their exercise regimens met the new guidelines, and to determine the level of support for exercise-therapy interventions in the management of hip-joint osteoarthritis.

METHODS

A systematic literature search of 14 electronic databases was undertaken to identify interventions that used exercise therapy as a treatment modality for hip osteoarthritis. The quality of each article was critically appraised and graded according to standardized methodologic approaches. A 'pattern-of-evidence' approach was used to determine the overall level of evidence in support of exercise-therapy interventions for treating hip osteoarthritis.

RESULTS

More than 4,000 articles were identified, of which 338 were considered suitable for abstract review. Of these, only 6 intervention studies met the inclusion criteria. Few well-designed studies specifically investigated the use of exercise-therapy management on hip-joint osteoarthritis. Insufficient evidence was found to suggest that exercise therapy can be an effective short-term management approach for reducing pain levels, improving joint function and the quality of life.

CONCLUSIONS

Limited information was available on which conclusions regarding the efficacy of exercise could be clearly based. No studies met the level of exercise recommended for individuals with osteoarthritis. High-quality trials are needed, and further consideration should be given to establishing the optimal exercises and exposure levels necessary for achieving long-term gains in the management of osteoarthritis of the hip.

Effects of cryotherapy on arthrogenic muscle inhibition using an experimental model of knee swelling

OBJECTIVE

Arthrogenic muscle inhibition (AMI) contributes to quadriceps weakness and atrophy in knee arthritis and following joint injury. This laboratory-based study examined the efficacy of cryotherapy in reducing quadriceps AMI caused by intraarticular swelling.

METHODS

Sixteen subjects without knee pathology participated, and were randomly assigned to a cryotherapy (n = 8) or control (n = 8) group. Surface electromyography (EMG) from vastus medialis and quadriceps torque measurements were recorded during maximum effort isometric contractions. All subjects then received an experimental joint infusion, whereby dextrose saline was injected into the knee to an intraarticular pressure of 50 mm Hg. EMG and torque measurements were repeated. Thereafter, the cryotherapy group had ice applied to the knee for 20 minutes while the control group did not receive an intervention. EMG and torque measurements were again collected. Quadriceps peak torque, muscle fiber conduction velocity (MFCV), and the root mean square (RMS) of EMG signals from vastus medialis were analyzed.

RESULTS

Quadriceps peak torque, MFCV, and RMS decreased significantly following joint infusion (P < or = 0.001). Cryotherapy led to a significant increase in quadriceps torque and MFCV compared with controls (P < 0.05). The difference in RMS did not reach statistical significance (P = 0.13).

CONCLUSION

The study demonstrated that cryotherapy is effective in reducing AMI induced by swelling. Cryotherapy may allow earlier and more effective quadriceps strengthening to occur in patients with knee joint pathology.

The effects of prior warning and lifting-induced fatigue on trunk muscle and postural responses to sudden loading during manual handling

This study investigated the effects of warning and lifting-induced fatigue on trunk muscle activity and postural responses to sudden loading. Thirty-one male subjects were subjected to sudden loading of a hand-held box with and without prior warning, before and after either lifting-induced fatigue or light callisthenic exercises. Results showed that warning did not alter the level of trunk muscle activity prior to sudden loading. Following warning, there was a reduction in all muscle and joint onset latencies and the magnitude of hip and knee flexion. Although fatigue did not influence muscle and joint initiation, it did negate the effects that warning had on reducing joint displacement. These findings indicate that warning prior to sudden loading may enhance postural responses, reduce ranges of joint motion and increase stability. However, the benefits of prior warning for reducing ranges of joint motion may not be present when a person is fatigued. Sudden unexpected loading and fatigue arising from manual handling practices in the workplace have been identified as contributing factors to the risk of low back injury. Findings from this study provide information that is important for the design of interventions intended to reduce the incidence of manual handling-related back injuries.

Acute neck pain: Cervical spine range of motion and position sense prior to and after joint mobilization

Despite the relatively high prevalence of cervical spine pain, the efficacy of treatment procedures is limited. In the current study, range of motion and proprioception was assessed prior to and after specific cervical spine mobilisation techniques. A 44-year-old male office worker presented with a history of cervical pain of 1 day duration. He had woken with pain, stiffness and a loss of range of motion. Examination findings indicated pain to be at C5-6 on the left side. Measurement of maximal three-dimensional cervical motion was undertaken using a Zebris system. A position matching task tested the individual's ability to actively reposition their head and neck. The treatment undertaken involved grade III down-slope mobilisations on the left side at C5-6 and C6-7 in supine lying. This technique was then progressed by placing the subject in an upright sitting position, and sustained natural apophyseal glides were performed at C6. Immediately following the treatment, the patient reported a considerable decrease in pain, less difficulty in movement and reduced stiffness. Motion analyses showed the most marked percentage improvements in range of motion after treatment were in flexion (55%), extension (35%), left rotation (56%), and left lateral flexion (22%). Ipsilateral lateral flexion with axial rotation was also notably improved following treatment. No change in proprioceptive ability was found following the treatment. The findings showed that the application of standardised specific mobilisation techniques led to substantial improvements in the range of motion and the restitution of normal coupled motion.

The lower-limb tasks questionnaire: an assessment of validity, reliability, responsiveness, and minimal important differences

OBJECTIVES

To develop a questionnaire that focuses only on physical tasks related to lower-limb function and, within that questionnaire, to explore the psychometric properties of a series of questions that are related specifically to activities of daily living (ADLs) and a series of activities more often associated with recreation.

DESIGN

Inception cohort.

SETTING

Private practice.

PARTICIPANTS

Data were primarily from patients who had experienced a lower-limb injury that would typically involve rehabilitation up to 6 weeks.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Through 5 studies, the following psychometric qualities were evaluated: content and factor validity, construct and concurrent validity, test-retest reliability (intraclass correlation coefficient [ICC], typical error), responsiveness (effect size, standardized response mean, Guyatt's responsiveness statistic), and the minimum important difference (distribution, anchor-based approaches).

RESULTS

Factor analysis supported the theoretical perspective that ADLs and recreational activities can be treated as different domains within the construct of function. Internal consistency was high (Cronbach alpha: ADLs, .91; recreational activities, .95) and the 2 domains explained a moderate level of the response variance (61%). In the ADL domain, 7 tasks had greater than 80% of participants regarding them as having some importance. For recreational activities, 6 tasks had 79% or more of participants regarding them as having some importance. Both domains were moderately correlated to actual performance of tasks (r = .62, r = .72), and to other questionnaires used for lower-limb injuries (r range, .51-.86). The floor and ceiling effects of the domains followed an expected pattern that could be related to the loading forces experienced on the injured limb during activities. The reliability of the 2 domains was high (ICCs >.95), and the Bland-Altman plots showed that the distribution of error across the range of scores was random with low bias scores (<1.0 point). Typical error scores were 2 points for each domain. All measures of responsiveness were high (1.2-6.7). Measures of the minimal important difference varied (3-10 points) according to the methodologic approach used.

CONCLUSIONS

The questionnaire possesses good factor structure and composition, relates well with other measures of function, differentiates patients with regard to certain characteristics or processes known to occur after injury, shows high levels of reliability and responsiveness, and shows evidence of good minimal important difference scores. The findings support the use of the questionnaire in both clinical scenarios and in research.

Interventions for the prevention and management of neck/upper extremity musculoskeletal conditions: a systematic review

Considered from medical, social or economic perspectives, the cost of musculoskeletal injuries experienced in the workplace is substantial, and there is a need to identify the most efficacious interventions for their effective prevention, management and rehabilitation. Previous reviews have highlighted the limited number of studies that focus on upper extremity intervention programmes. The aim of this study was to evaluate the findings of primary, secondary and/or tertiary intervention studies for neck/upper extremity conditions undertaken between 1999 and 2004 and to compare these results with those of previous reviews. Relevant studies were retrieved through the use of a systematic approach to literature searching and evaluated using a standardised tool. Evidence was then classified according to a "pattern of evidence" approach. Studies were categorised into subgroups depending on the type of intervention: mechanical exposure interventions; production systems/organisational culture interventions and modifier interventions. 31 intervention studies met the inclusion criteria. The findings provided evidence to support the use of some mechanical and modifier interventions as approaches for preventing and managing neck/upper extremity musculoskeletal conditions and fibromyalgia. Evidence to support the benefits of production systems/organisational culture interventions was found to be lacking. This review identified no single-dimensional or multi-dimensional strategy for intervention that was considered effective across occupational settings. There is limited information to support the establishment of evidence-based guidelines applicable to a number of industrial sectors.

The effects of prior exposure, warning, and initial standing posture on muscular and kinematic responses to sudden loading of a hand-held box

BACKGROUND

Twelve percent of work-related low back injuries have been attributed to sudden loading events. When a sudden load is applied to an object that is held in front of the body, postural responses are rapid, yet it is not clear whether these responses differ with respect to initial posture at the time of loading, or by providing prior exposure to, or warning of a sudden loading event.

METHODS

Thirty male subjects in either an upright or stooped standing posture held a pre-weighted box that was suddenly pulled downwards. Surface electromyography techniques were used to detect onset latencies of seven muscles of the right lower limb and trunk, and two-dimensional motion data in the sagittal plane were simultaneously collected. The first trial involved sudden unexpected loading in the upright standing posture, without any prior experience or warning of the loading event. This was followed by a series of randomised loading trials in the upright and stooped standing posture, with and without prior warning of the loading event.

FINDINGS

Prior exposure and warning was found to influence postural responses in the upright standing posture, decreasing muscle and joint onset latencies, and resultant maximal angular displacement of the trunk and lower limb. Perturbation in the stooped posture was less reliant on abdominal muscle activation and produced an overall different joint movement initiation pattern, with less joint displacement than in the upright standing position.

INTERPRETATION

These findings indicate that prior exposure to, and warning of a sudden loading event lead to changes in postural responses and decreased joint excursion. These changes may contribute to increased stability and decreased risk of musculoskeletal injury.

Management of symphysis pubis dysfunction during pregnancy using exercise and pelvic support belts

BACKGROUND AND PURPOSE

Symphysis pubis pain is a significant problem for some pregnant women. The purpose of this study was to investigate the effects of exercise, advice, and pelvic support belts on the management of symphysis pubis dysfunction during pregnancy.

SUBJECTS

Ninety pregnant women with symphysis pubis dysfunction were randomly assigned to 3 treatment groups.

METHODS

A randomized masked prospective experimental clinical trial was conducted. Specific muscle strengthening exercises and advice concerning appropriate methods for performing activities of daily living were given to the 3 groups, and 2 of the groups were given either a rigid pelvic support belt or a nonrigid pelvic support belt. The dependent variables, which were measured before and after the intervention, were a Roland-Morris Questionnaire score, a Patient-Specific Functional Scale score, and a pain score (101-point numerical rating score).

RESULTS

After the intervention, there was a significant reduction in the Roland-Morris Questionnaire score, the Patient-Specific Functional Scale score, and the average and worst pain scores in all groups. With the exception of average pain, there were no significant differences between groups for the other measures.

DISCUSSION AND CONCLUSION

The findings indicate that the use of either a rigid or a nonrigid pelvic support belt did not add to the effects provided by exercise and advice.

Effects of an eight-week stretching program on the passive-elastic properties and function of the calf muscles of older women

BACKGROUND

Calf muscle stretching programs are used to increase dorsiflexion range of motion at the ankle, yet the effects of the stretching programs on the passive properties of aged calf muscles and on standing and ambulatory function have not been studied. This initial study examined the effects of an eight-week stretching program on the passive-elastic properties of the calf muscles of older women and on selected functional activities.

METHODS

Nineteen women aged 65-89 years with limited dorsiflexion range of motion first completed a timed agility course, a timed 10-m walk and a standing functional reach test. A dynamometer then moved the right ankle from plantarflexion to maximal dorsiflexion and back to plantarflexion at 5 deg s(-1) to measure calf muscle passive properties. The women were randomly assigned to a group that stretched three-times a week for eight-weeks (n=10) or to a control group (n=9) that did not. The tests were repeated after the stretching program.

FINDINGS

The stretching group showed increased maximal dorsiflexion range of motion, passive resistive forces (Newtons [N]), and the absorbed and retained passive-elastic energy (deg N) (P<0.05). They also had decreased times for the agility course and the 10-m walk (P<0.05). The functional reach test did not change for either group.

INTERPRETATION

The eight-week stretching program most likely increased the maximal length, length extensibility and passive resistive forces of the calf muscles. Adaptations of other ankle and leg structures also may have contributed. The passive adaptations were associated with enhanced performances of ambulatory functional activities.

Head and neck position sense in whiplash patients and healthy individuals and the effect of the cranio-cervical flexion action

BACKGROUND

Whiplash may damage structures within the neck that can affect position sense. Deep neck flexor muscle retraining may improve position sense. The current study compared range of motion and position sense in whiplash and control subjects and investigated the effects of a muscle training session on position sense.

METHODS

Twenty-three subjects with whiplash were compared with a matched control group. Range of motion and neck position sense measures were recorded using the 3-Space Fastrak. Measures of function were also assessed in the whiplash group. Subjects were then randomised into experimental and control groups and the former group received a training session to activate the deep neck flexor and scapular stabilising muscles (the cranio-cervical flexion action) during head and neck movements. After training, position sense measures were re-evaluated.

FINDINGS

Results showed significant reductions (P < 0.05) in active range of motion in the whiplash group when compared to the healthy group. No significant differences (P > 0.05) between whiplash and healthy groups in position matching accuracy were observed. Functional outcome scores indicated the whiplash group to be mildly disabled. No effect on error scores was observed when position-matching tasks were performed with and without the cranio-cervical flexion action. Correlations between functional measures or range of motion, and position sense were not significant.

INTERPRETATION

There was no evidence of position sense impairment in the mildly disabled whiplash subjects. The performance of the cranio-cervical flexion action had no effect on position sense, and hence clinical improvements observed from using this action may be more associated with mechanical stabilisation.