Biomechanical assessment of the central band of the interosseous membrane using shear wave elastography: reliability and reproducibility.

The interosseous membrane of the forearm is an essential structure for the stability of the forearm skeleton, the most important part being the central band. The purpose of this study was to determine if shear wave elastography, a non-invasive ultrasound technique, can be used to measure shear wave speed in the central band and quantify stiffness. Fifteen healthy adult subjects were included (30 forearms). The participants forearms were positioned on an articulated plate, with their hand in neutral, pronated and then supinated positions of 30°, 60° and 90°. The shear wave speed was highest in 90° pronation (4.4 m/s (SD 0.3)) and 90° supination (4.4 m/s (SD 0.27)) indicating maximum stiffness in these positions. Its minimum value was in the neutral position, and either in 30° pronation or supination (3.5 m/s (SD 0.3)). Intra- and interobserver agreement was excellent, regardless of probe positioning or forearm mobilization. This study presents a reliable shear wave elastography measurement protocol to describe the physiological function of the central band of the interosseous membrane in healthy adults.Level of evidence: IV.

Volar locking plate fixation of distal radius fractures: Isokinetic assessment of the influence of an ulnar styloid process fracture on pronation-supination strength.

Although distal radius fractures (DRF) are frequent, the management of associated ulnar styloid process (USP) lesions is still controversial. According to recent studies, a fracture of the USP does not appear to affect functional outcomes after treatment of a DRF with plate fixation. We sought to compare the impact of a USP fracture on pronation and supination strength in isometric and isokinetic tests. We included patients with a DRF who underwent volar locking plate fixation. We divided our population into three groups: one group consisted of patients who had a fracture of the USP base, one group composed of patients without USP fracture or with a distal ulnar fracture only, and a control group composed of subjects with normal wrists. Inclusion criteria included an age of 18 to 50 years and a minimum follow-up of 10 months post-surgery. The main exclusion criteria were complex intraarticular fractures and postoperative complications. The assessment was based on clinical examination and recording of forearm rotation strength during pronation and supination in isokinetic and isometric tests. The ratio between the operated and contralateral sides was compared for each patient. Thirty-six participants were included (mean age 31.1±4.5 years). The mean postoperative follow-up was 17.9±6.9 months. Participants with a USP fracture differed from other participants in their peak torque on the isokinetic test at 45°/s for pronation and supination, but not on isokinetic tests at 120°/s or in isometric tests. Isokinetic tests revealed a decrease in pronation-supination strength during sustained effort for patients with associated basal USP fractures. These findings may have clinical implications for management of the USP but need to be specified with further study. LEVEL OF EVIDENCE: prognostic study level III.

A minimal markerset for three-dimensional foot function assessment: measuring navicular drop and drift under dynamic conditions.

BACKGROUND: The validity of predicting foot pronation occurring mainly at the midfoot by surrogate measures from the rearfoot, like eversion excursion, is limited. The dynamic navicular mobility in terms of vertical navicular drop (dNDrop) and medial navicular drift (dNDrift) may be regarded as meaningful clinical indicators to represent overall foot function. This study aimed to develop a minimal approach to measure the two parameters and to examine their intra- and interday reliability during walking. METHODS: The minimal markerset uses markers at the lateral and medial caput of the 1st and 5th metatarsals, respectively, at the dorsal calcaneus and at the tuberosity of the navicular bone. Dynamic navicular drop and drift were assessed with three-dimensional motion capture in 21 healthy individuals using a single-examiner test-retest study design. RESULTS: Intra- and interday repeatability were 1.1 mm (ICC21 0.97) and 2.3 mm (ICC21 0.87) for dynamic navicular drop and 1.5 mm (ICC21 0.96) and 5.3 mm (ICC21 0.46) for dynamic navicular drift. The contribution of instrumental errors was estimated to 0.25 mm for dynamic navicular drop and 0.86 mm for dynamic navicular drift. CONCLUSIONS: Interday reliability was generally worse than intraday reliability primary due to day-to-day variations in movement patterns and the contribution of instrumental errors was below 23% for dynamic navicular drop but reached 57% for dynamic navicular drift. The minimal markerset allows to simply transfer the known concepts of navicular drop and drift from quasi-static clinical test conditions to functional tasks, which is recommended to more closely relate assessments to the functional behavior of the foot.

How accurate is visual determination of foot strike pattern and pronation assessment.

Nowadays, choosing adequate running shoes is very difficult, due to the high number of different designs. Nevertheless, shoes have two main characteristics to fit runners' technique and morphology: drop and arch support. Retailers' advices are usually based on the visual assessment of the customer's running technique. Such method is subjective and requires an experimented examiner while objective methods require expensive material, such as 3D motion system and pressure insoles. Therefore, the aim of this study was to determine the accuracy of foot strike pattern and pronation assessment using video cameras, compared to a gold standard motion tracking system and pressure insoles. 34 subjects had to run at 8, 12 and 16 Km/h shod and 12 Km/h barefoot during 30 s trials on a treadmill. Agreement between foot strike pattern assessment methods was between 88% and 92%. For pronation, agreement on assessment methods was between 42% and 56%. The results obtained indicate a good accuracy on foot strike pattern assessment, and a high difficulty to determine pronation with enough accuracy. There is therefore a need to develop new tools for the assessment of runner's pronation.

In Vitro Kinematic Assessment of a Hinged Elbow Orthosis Following Lateral Collateral Ligament Injury.

PURPOSE: Elbow lateral collateral ligament injuries (LCLI) are often managed with protected mobilization using a hinged elbow orthosis (HEO). The objective of this investigation was to determine the effectiveness of an HEO in stabilizing the elbow following LCLI. METHODS: Seven fresh-frozen cadaveric upper extremity specimens were studied using a custom simulator that enabled elbow motion via computer-controlled actuators and servomotors attached to relevant tendons. Specimens were examined in 4 arm positions (dependent, overhead, horizontal, and varus) and 2 forearm positions (pronation and supination) during both passive and simulated active elbow extension. Specimens were examined before and after simulated LCLI, and then with the addition of an HEO. The lateral collateral ligament, common extensor origin, and lateral elbow capsule were sectioned in the injury model. An electromagnetic tracking system measured ulnohumeral kinematics. RESULTS: The orthosis did not change elbow stability in any arm position during active motion. Muscle activation and forearm pronation enhanced stability in the dependent, horizontal, and varus positions while the HEO was applied. CONCLUSIONS: This HEO does not improve the in vitro stability of the elbow following simulated LCLI. CLINICAL RELEVANCE: An HEO may be safe to use during active motion, but when a patient is not activating the muscles normally (ie, owing to fatigue or cognitive impairment) and the arm is in positions in which the weight of the orthosis might increase joint distraction, an HEO may be harmful. If an HEO is used, the forearm should be braced in pronation following LCLI.

Reliability assessment of measuring active wrist pronation and supination range of motion with a smartphone.

This study aimed to improve clinical examination techniques by determining the reliability of different methods to evaluate forearm movements. Two methods using the iPhone™ 5 and its gyroscope application (alone [I5] or attached to a selfie stick [ISS]) were compared with two conventional measurement devices (a plastic goniometer with a hand-held pencil [HHP] and a bubble goniometer [BG]) to evaluate the active range of movement (AROM) of the wrist during pronation and supination. Two independent groups of subjects took part in this prospective single-center diagnostic study: 20 healthy subjects and 20 patients. The four evaluation methods had high intra-observer consistency after three measurements (intra-class correlation coefficient [ICC] [3, 1] of 0.916 for the HHP; 0.944 for ISS; 0.925 for BG; 0.933 for I5) and excellent inter-observer reliability (ICC [2, k] of 0.926 for HHP; 0.934 for ISS; 0.899 for BG; 0.894 for I5), with an agreement of plus or minus 2°. When these devices are used with rigorous methodology, they are reliable for the goniometric evaluation of AROM of wrist pronation and supination.

The assessment of three-dimensional foot pronation using a principal component analysis method in the stance phase of running.

Foot pronation has not been quantified dynamically in three planes of movement in an in-vivo study. The aims of this study were to determine foot pronation through using Principal Component Analysis (PCA) method and to compare it among barefoot, shod and shod with 6° lateral wedge during the stance phase of running. In this method, three-dimension of foot movements were measured and each of these components represents a percentage of foot pronation. These components were derived based on eigenvalues and vectors of covariance matrix of primary variables. The first (PC1), second (PC2) and third (PC3) components explained about (82.5%, 79.1%), (14%, 15.8%) and (3.5%, 5.1%) the foot pronation for barefoot and shod conditions, respectively. These components were mutually independent and the components set had the same information as the primary variables. Foot pronation index and eversion angles were calculated and compared among barefoot, shod and shod with wedge insole (6° lateral wedge insole) conditions in the four phases of stance. Statistical analysis showed that there was no foot conditions effect for foot eversion in four phases (p=0.72), while this effect was significant for PC1 (p=0.001). This finding shows that PC1 index could discriminate footwear effect among each phase of stance. Specifically, pronation was reduced in shoe condition as compared to barefoot condition (p=0.02) from 5 to 50% of stance phase. It has been suggested that the PCA method provides more accurate criteria for investigating effects of footwear interventions on simultaneous three-dimensional foot motion.

Assessment of cognitive engagement in stroke patients from single-trial EEG during motor rehabilitation.

We propose a novel method for monitoring cognitive engagement in stroke patients during motor rehabilitation. Active engagement reflects implicit motivation and can enhance motor recovery. In this study, we used electroencephalography (EEG) to assess cognitive engagement in 11 chronic stroke patients while they executed active and passive motor tasks involving grasping and supination hand movements. We observed that the active motor task induced larger event-related desynchronization (ERD) than the passive task in the bilateral motor cortex and supplementary motor area (SMA). ERD differences between tasks were observed during both initial and post-movement periods . Additionally, differences in beta band activity were larger than differences in mu band activity . EEG data was used to help classify each trial as involving the active or passive motor task. Average classification accuracy was 80.7 ±0.1% for grasping movement and 82.8 ±0.1% for supination movement. Classification accuracy using a combination of movement and post-movement periods was higher than in other cases . Our results support using EEG to assess cognitive engagement in stroke patients during motor rehabilitation.

Ultrasonographic assessment of the flexor pronator muscles as a dynamic stabilizer of the elbow against valgus force.

Flexor pronator muscles (FPMs) play a key role in stabilizing the elbow joint against valgus forces. However, no studies have investigated the in vivo kinematics of FPMs against these forces on the elbow. This study aimed to clarify the in vivo contribution of each FPM as a dynamic stabilizer in a clinical situation.Twelve healthy volunteers participated in this study. Verbal informed consent was obtained from all subjects. The elbow was flexed to 90 degrees, and the forearm was placed in the neutral position. Manual valgus stress was applied to the elbow joint until maximal shoulder external rotation was achieved. The width of the ulnohumeral joint space and the ulnar shift of the sublime tubercle were measured before and after isometric contraction of FPMs using ultrasonography.The horizontal distances were decreased 1.1±0.6 mm after forearm pronation, 0.6±0.5 mm after wrist palmar flexion, 0.1±0.4 mm after wrist ulnar flexion, and 0.2±0.5 mm after finger flexion. Significant changes were observed during forearm pronation, wrist palmar flexion, and finger flexion but not during wrist ulnar flexion (p<0.05). The sublime tubercle was significantly shifted 0.5±0.1 mm medially after forearm pronation, 0.2±0.1 mm medially after wrist palmar flexion, and 0.1±0.1 mm laterally after wrist ulnar flexion and finger flexion (p<0.05). The FPMs, especially the pronator teres and the flexor carpi radialis, function as dynamic stabilizers against elbow valgus stress. The results of this study may be useful in developing injury prevention and rehabilitation strategies for throwing injuries of the elbow.

Biomechanical assessment of brachioradialis pronatorplasty.

OBJECTIVES: Transfer of the brachioradialis muscle, proposed by Özkan et al. can be applied to cases, in which, the biceps rerouting technique is not appropriate for the correction of forearm supination contracture and restoration of active pronation. We have aimed to assess the biomechanical effects of the brachioradialis transfer. METHODS: Pronation strength was acquired in nine fresh-frozen cadaver forearms by applying rerouting of the brachioradialis muscle through interosseous membrane (Group 1) or transferring the same muscle to the distal insertion of extensor carpi ulnaris (ECU) (Group 2). Then, a force of 5 to 35 N was applied to the muscle and the range of forearm rotation and rotation strength were measured. The normalities of the data were analyzed by Shapiro-Wilk test. Comparisons between the groups were made with independent-sample t-test and comparison of the data, obtained from the same group, was carried out with paired-sample t-test and Bonferroni correction. RESULTS: A maximum of 74° (with a mean of 61°) gain of pronation with rerouting and a maximum of 72° (with a mean of 65°) gain with ECU transfer of brachioradialis muscle were observed. A significant regression was also found in the first group. Regression constant was - 9.59 (p = 0.001, 95%: -13.20; -6.00) for the applied force of 2.06 N (p = 0.001, 95%: 1.90; 2.22). Furthermore, a significant regression was found in the second group. Regression constant was - 9.73 (p = 0.001, 95%: -13.13; -6.34) for the applied force of 1.91 N (p = 0.001, 95%: 1.76; 2.06). CONCLUSION: The brachioradialis muscle works as a pronator in full forearm supination. However, when the forearm comes close to the neutral rotation, due to the lateral location of the proximal insertion, the brachioradialis muscle loses this pronator effect. The additional release or lengthening of contracted soft tissues increases the range of pronation.

An assessment of strapping techniques commonly used for pronated foot deformities.

BACKGROUND: This study investigated the effects of two low-Dye and two high-Dye strapping techniques that are commonly used to treat pronatory sequelae. METHODS: Plantar pressure distribution in normal adults with a pronated foot type was assessed with a commercially available pressure platform system. Twenty study participants first walked across the platform barefoot and then with each of the four strapping conditions applied. The footprints were averaged and divided into seven areas for analysis. RESULTS: Paired t tests found significant differences between the barefoot and strapping conditions. Overall, there was a general lateralization of pressures indicating an antipronation effect from all strapping conditions. Low-Dye strap 2, used to limit the degree of calcaneal eversion, produced the most significant changes at the foot pressure areas analyzed. CONCLUSIONS: The data reported in this study suggest that the four strapping techniques offer different levels of control, and this should be considered during the decision-making process and clinical management of pronatory conditions. It was the contention of this study that low-Dye strap 2 was the most effective strapping technique to control foot mechanics associated with a pronated foot type.

Assessment of distal radioulnar joint instability after distal radius fracture: comparison of computed tomography and clinical examination results.

PURPOSE: To compare computed tomography (CT) and clinical stress test findings in terms of the assessment of distal radioulnar joint (DRUJ) instability after distal radius fracture. METHODS: Thirty-four patients with a healed unilateral distal radius fracture were evaluated after a mean follow-up period of 18 months. Stress test and CT were performed to detect DRUJ instability. Three CT methods were used: the modified radioulnar line, the epicenter, and the radioulnar ratio methods. The results of CT assessments were compared with stress test findings using kappa statistics. Relationships between DRUJ instability and the radiographic parameters of volar tilt, radial inclination, and radial shortening were analyzed. RESULTS: Twelve patients were considered to have DRUJ instability based on the stress test. DRUJ instability was diagnosed in 15, 8, and 11 patients by the modified radioulnar line, the epicenter, and the radioulnar ratio methods, respectively. Reliability analysis of stress test and CT results showed moderate or fair agreement (kappa value: .33 for the modified radioulnar line, .56 for the epicenter, .41 for the radioulnar ratio). DRUJ instability diagnosed by the stress test and by CT showed no statistical correlation with radiographic parameters, but instability determined by CT appeared to be related to dorsal tilt deformity. CONCLUSIONS: After distal radius fracture, CT assessments of DRUJ instability were found to be influenced by residual deformities, such as dorsal tilt, but not well correlated with stress test findings. Although CT assessments are objective, CT scans primarily show alterations of DRUJ alignment and have several risks of bias in patients with a prior distal radius fracture.

In vitro validation of a technique for assessment of canine and feline elbow joint collateral ligament integrity and description of a new method for collateral ligament prosthetic replacement.

OBJECTIVE: To assess the ability of an operator to differentiate intact from transected canine and feline elbow joint collateral ligaments (CL) using a reported manipulative test (Campbell's test) and to determine the potential for elbow joint luxation in canine and feline elbows with intact, transected, and surgically stabilized CL. STUDY DESIGN: In vitro biomechanical study. SAMPLE POPULATION: Canine (n=6) and feline cadavers (n=3). METHODS: Thoracic limb specimens were mounted on a custom-built jig with the elbows and carpi fixed in 90 degrees of flexion. Angles of pronation and supination were recorded after applying rotational forces to the manus. Attempts were made to manually luxate each elbow with intact CL. Constructs were re-evaluated after sequential sectioning of the medial (MCL) and lateral (LCL) collateral ligaments and after insertion of a new CL prosthesis. RESULTS: Mean (+/-SD) angles of rotation in dogs increased from 27.3+/-8 degrees (range, 16.7-41.3 degrees ) in pronation to 58.9+/-9.2 degrees (range, 38-88.3 degrees ) after sectioning the MCL and from 45.5+/-10.8 degrees (range, 30.7-67.3 degrees ) in supination to 68.9+/-17.2 degrees (range, 45-94 degrees ) after sectioning the LCL. Angles of pronation and supination were subject to significant interanimal variability, with a strong correlation between increasing animal weight and smaller angles of rotation. Elbow luxation in dogs was not possible unless at least the LCL was transected. In cats, mean angles of rotation increased from 49.8+/-14.9 degrees (range, 30.7-70 degrees ) in pronation to 99.1+/-17.6 degrees (range, 79-111.7 degrees ) after sectioning the MCL and from 128.7+/-18.8 degrees (range, 108.3-151.7 degrees ) in supination to 166.7+/-13.1 degrees (range, 157.3-181.7 degrees ) after sectioning the LCL. Luxation in cats was not possible unless both CL were cut. Use of the ligament prosthesis without primary CL repair reliably prevented reluxation in all canine and feline elbows. CONCLUSIONS: Campbell's test allowed reliable differentiation of intact, transected and surgically stabilized canine and feline elbow joint CL in a cadaveric model. Luxation could not be performed by application of rotational forces to specimens with intact CL. CLINICAL RELEVANCE: Clinical examination findings, specifically Campbell's test, can be used to determine elbow CL integrity in dogs and cats. The contralateral elbow should be used as a control, because of interanimal variability in angles of rotation.

Assessment of forearm pronation strength in C6 and C7 radiculopathies.

STUDY DESIGN: Consecutive case series of patients with C6 and C7 radiculopathies. OBJECTIVES: To explore the clinical utility and reliability of manual muscle testing of forearm pronation strength in C6 and C7 radiculopathies. SUMMARY OF BACKGROUND DATA: EMG evidence of denervation of the pronator teres was the most common finding in C6 radiculopathies, and frequently present in C7 radiculopathies. Clinical evaluation of the pronator teres through manual muscle testing of forearm pronation has never been explored; therefore, its clinical utility is unknown as compared with the muscle groups that are traditionally evaluated. METHODS: Fifty-five subjects with diagnostic imaging evidence of either C6 (n = 25) or C7 (n = 30) cervical root compression and clinical symptoms consistent with cervical radiculopathy were recruited for this study. These subjects underwent manual muscle testing of forearm pronation, wrist extension, elbow flexion, and elbow extension. The frequency of impaired strength was recorded and compared for C6 and C7 radiculopathies. A second examiner evaluated each subject, with his or her findings compared with the first examiner only for the determination of interrater reliability. RESULTS: In C6 radiculopathy subjects, forearm pronation weakness was present in 72%, was twice as common as wrist extension weakness, was present in all cases where elbow flexion or wrist extension weakness was noted, and was found in all but 2 subjects where elbow extension weakness was present. In C7 radiculopathy subjects, forearm pronation weakness accompanies elbow extension weakness in 23% of subjects and was the only weakness in 10% of subjects. Manual muscle testing demonstrated adequate interrater reliability. CONCLUSIONS: Forearm pronation weakness is the most frequent motor finding in C6 radiculopathies and may be noted is some cases of C7 nerve root compression.

Assessment of radial and ulnar torsion profiles with cross-sectional magnetic resonance imaging. A study of volunteers.

BACKGROUND: We determined whether the torsion profiles of the radius and ulna could be reliably assessed with cross-sectional magnetic resonance imaging and whether these torsion profiles were comparable on the two sides of volunteers. METHODS: We assessed magnetic resonance imaging cross sections of the left and right forearms of twenty-four asymptomatic volunteers. The torsion profile of the ulna was defined as the angle formed between a line tangential to the volar cortical surface of the distal part of the humerus and a line connecting the center of the ulnar head and the center of the ulnar styloid. Use of paired proximal and distal landmarks resulted in five different methods of assessment of the radial torsion profile. Intrarater and interrater reliabilities and side-to-side variability were assessed. RESULTS: This method of assessment of the ulnar torsion profile had intraclass and interclass coefficients of 0.95 and 0.91, respectively. A method previously described by Bindra et al. had the best combined intrarater and interrater reliabilities for assessment of the radius. The mean differences between the right and left sides of the volunteers were the lowest with the use of these two methods; nevertheless, the maximum side-to-side difference was > 30 degrees with techniques. CONCLUSIONS: Torsion-profile assessment with cross-sectional magnetic resonance imaging had high intrarater and interrater reliabilities. However, individual side-to-side variations in the radial and ulnar profiles are important considerations. CLINICAL RELEVANCE: Cross-sectional magnetic resonance imaging is currently the only available method to quantify rotational malunion of the radius and ulna. Its low side-to-side reliability warrants comparison between the imaging results and the clinical findings. A side-to-side difference in the rotation profile may serve as a reason to perform an axial osteotomy when the results of the clinical and magnetic resonance imaging assessments are consistent with each other.

Clinicians' assessment of the hindfoot: a study of reliability.

BACKGROUND: Static measurements of position of the hindfoot and clinical assessment of motion of the hindfoot often are used in the assessment of foot function and manufacturing of orthoses. However, the reliability and validity of static measurements and dynamic observation and assessment of the hindfoot are controversial. The purpose of this investigation was to examine reliability of static and dynamic assessments of the hindfoot in a setting that reproduced clinical conditions. METHODS: Twenty-four healthy participants were evaluated by four experienced clinicians for four commonly used static measurements and dynamic assessment of hindfoot function. The protocol was repeated 2 weeks later. RESULTS: Results indicated that reliability of results, both intertester and from test to test were poor to fair for static measurements of the hindfoot (r = 0.075 to r = 0.755, p < 0.05). The error estimates associated with these measures were high; subtalar neutral position and resting calcaneal stance position both demonstrated measurement errors of more than 4 degrees (95% confidence intervals-4.1 degrees and 5.1 degrees, respectively). Retest reliability of dynamic assessments were considered reasonable for only one clinician (kappa = 0.55). Intertester agreement was poor among all clinicians. CONCLUSION: Clinicians taking static measurements demonstrated large errors that do not reflect the precision that has been assumed in clinical theory using these measurements. The availability of static assessments did not improve dynamic assessment. This poor reliability calls into question the importance placed on static and dynamic measurements of the hindfoot in clinical decision-making.

Treatment of distal radius fractures with a low-profile dorsal plating system: an outcomes assessment.

PURPOSE: To evaluate objective functional and radiographic outcomes after internal fixation of acute, displaced, and unstable fractures of the distal aspect of the radius in adults by using a low-profile dorsal plating system. Our hypothesis was that the low-profile dorsal plating system would allow for a reduction of extensor tendon irritation and pain and provide stable osseous fixation. METHODS: Sixty consecutive unstable fractures in 59 patients were treated by open reduction internal fixation using a low-profile dorsal plating system. There were 29 type A, 14 type B, and 8 type C fractures (AO classification system). Fifty patients with 51 fractures returned for outcomes assessment by physical examination, plain radiographs, and completion of a validated musculoskeletal function assessment questionnaire. The minimum follow-up period was 1 year; the mean follow-up period was 24 months. Clinical evaluation was performed and plain radiographs were assessed for maintenance of immediate postoperative reduction and implant position. Objective functional assessment was obtained through the Disabilities of the Arm, Shoulder, and Hand questionnaire. RESULTS: Outcomes analysis showed no cases of extensor tendon irritation or rupture. Hardware removal was performed in 1 patient but no extensor tendon irritation or rupture was evidenced. The mean Disabilities of the Arm, Shoulder, and Hand score was 11.9; implant-related discomfort was minimal. All patients had an excellent (31 patients) or good (19 patients) result according to the scoring system of Gartland and Werley. The mean active range of motion was greater than 80% of that of the contralateral wrist in flexion/extension, pronation/supination, and ulnar/radial deviation. Extensor tendon function was unimpaired in all patients. Grip and pinch strength averaged 90% and 94% of the contralateral sides, respectively. Radiographic evaluation showed no change in fracture reduction or implant position. CONCLUSIONS: The treatment of distal radius fractures with a low-profile stainless steel dorsal plating system is a safe and effective method that provides stable internal fixation and allows for full extensor tendon glide and full metacarpophalangeal joint motion. Objective outcome testing showed uniformly good to excellent recovery of wrist and hand function in all patients. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Screw fixation of scaphoid fractures: a biomechanical assessment of screw length and screw augmentation.

PURPOSE: To assess the biomechanical stability relative to screw length and K-wire augmentation in scaphoid fracture fixation using a flexibility testing protocol and cadaver scaphoids whose soft tissue attachments remained undisturbed. Our hypothesis was 2-fold: increasing screw length and augmenting fixation with a K-wire would improve fracture fragment stability, individually and in combination. METHODS: Flexion and extension loading applied through wrist tendons was performed on 10 cadaveric wrists after volar wedge scaphoid osteotomy and internal fixation. Each wrist participated in 3 experimental groups: short screw, long screw, and long screw augmented with a K-wire transfixing the distal pole to the capitate. Interfragmentary displacements were measured. RESULTS: Analysis of variance showed significantly less fracture fragment motion with longer screws than with short screws in 4 of the 6 displacement axes. The flexion/extension axis rotations for the short, long, and augmented long-screw groups were 8.2 degrees +/- 4.8 degrees, 3.9 degrees +/- 1.6 degrees, and 1.8 degrees +/- 1.3 degrees, respectively. Although K-wire augmentation reduced displacement of the fracture fragments it did not decrease interfragmentary motion significantly when compared with the long-screw group. CONCLUSIONS: Under physiologically applied loading of cadaveric wrists with unstable scaphoid waist fractures the long screw provided significantly greater stability than the short screw. Although K-wire augmentation in the long-screw group did improve stability the improvements were not significant. Based in part on the biomechanical data from this study it is our recommendation that the optimally placed screw for scaphoid fracture fixation stability is a long screw positioned down the central axis of the scaphoid deep into subchondral bone.

Dynamic foot-pressure measurement in the assessment of operatively treated clubfeet.

BACKGROUND: Decreased motion of the subtalar joint is common after operative treatment of idiopathic clubfeet. The purposes of this study were to validate parameters of dynamic foot-pressure measurement that enable detection of physiological pronation of the subtalar joint and to analyze the consequences of absent or decreased pronation following clubfoot surgery on long-term functional results. METHODS: To validate parameters of dynamic foot-pressure measurement, we initially analyzed two control groups: one of forty asymptomatic normal feet and the other of five feet with a previous subtalar joint arthrodesis. The resulting parameters were then applied to a group of nineteen patients with twenty-four idiopathic clubfeet for whom initial conservative treatment had failed and in whom a posterior surgical release (lengthening of the Achilles tendon and release of the posterior ankle capsule) had been performed at a mean age of twenty months. The mean duration of follow-up was forty-one years. All feet were evaluated radiographically, and the clinical results were assessed with the American Orthopaedic Foot and Ankle Society score. RESULTS: An interruption in the rise of the pressure-time curve and a short medial deviation of the center of pressure path immediately after heel strike are reliable and objective characteristics of pronation movement of the subtalar joint. Nineteen clubfeet had a demonstrable pronation movement, and five clubfeet did not. The nineteen feet with pronation movement were either asymptomatic (twelve feet) or mildly painful on occasion (seven feet). The mean American Orthopaedic Foot and Ankle Society score for the nineteen feet was 87 points. The five feet without pronation movement were moderately painful during strenuous activities only (four feet) or were nearly always painful (one foot). The mean score for those feet was 57 points. There was a significant difference between these two groups with regard to the pain scores and the total scores (p < 0.001), but there was no appreciable difference regarding function and hindfoot motion. It was not possible to distinguish between these two groups on the basis of the findings of the physical or radiographic examinations. CONCLUSIONS: Idiopathic clubfeet with preserved hindfoot pronation have a better long-term prognosis. Preservation of functional mobility of the subtalar joint is a key factor in the treatment of clubfoot deformity.

Outcome assessment after arthrolysis of the elbow.

BACKGROUND: In the literature, the outcome after arthrolysis of the elbow is mainly assessed by range of motion (ROM). Our intention was to verify whether this parameter does sufficiently estimate the outcome after surgical arthrolysis. METHODS: We performed a retrospective study using the validated Disability of the Arm, Shoulder, and Hand Questionnaire (DASH) as our reference outcome parameter. This score was compared with other outcome parameters such as ROM, Mayo Performance Index (MPI) and SF-36. A total of 59 patients who underwent arthrolysis of the elbow was evaluated 53 months after surgery on average. RESULTS: The mean ROM was 101 degrees for flexion/extension with a relative gain of 60% and 134 degrees for pronation/supination with a relative gain of 58%. MPI was 84 points on average. The mean DASH was 17.6 and the mean SF-36 67.9. The correlation of these outcome parameters was calculated using Pearson's correlation (two-tailed, significance set at p<0.05). We found a high correlation between DASH and the physical function part of the SF-36 (Cov=-0.87, p<0.05). The correlation of DASH and MPI was moderate (Cov=0.71, p<0.05) and of DASH and ROM poor (Cov=-0.25, p<0.05). CONCLUSION: ROM as a single parameter does not sufficiently assess the outcome of arthrolysis of the elbow.