Prosthesis Experience Research Articles

EMG Pattern Recognition Control of the DEKA Arm: Impact on User Ratings of Satisfaction and Usability.

The DEKA Arm has multiple degrees of freedom which historically have been operated primarily by inertial measurement units (IMUs). However, the IMUs are not appropriate for all potential users; new control methods are needed. The purposes of this study were: 1) to describe usability and satisfaction of two controls methods—IMU and myoelectric pattern recognition (EMG-PR) controls—and 2) to compare ratings by control and amputation level. A total of 36 subjects with transradial (TR) or transhumeral (TH) amputation participated in the study. The subjects included 11 EMG-PR users (82% TR) and 25 IMU users (68% TR). The study consisted of in-laboratory training (Part A) and home use (Part B). The subjects were administered the Trinity Amputation and Prosthesis Experience satisfaction scale and other usability and satisfaction measures. Wilcoxon rank-sum tests compared the differences by control type. The differences were compared for those who did and did not want a DEKA Arm. The preferences for features of the DEKA Arm were compared by control type. The comparisons revealed poorer ratings of skill, comfort, and weight among EMG-PR users. The TR amputees using IMUs rated usability more favorably. TH amputees rated usability similarly. The TR amputees using EMG-PR were less satisfied with weight, pinch grip, and wrist display, whereas the TH amputees were less satisfied with the full system, wires/cables, and battery. Usability and satisfaction declined after Part B for EMG-PR users. Overall, we found that the IMU users rated the DEKA Arm and the controls more favorably than the EMG-PR users. The findings indicate that the EMG-PR system we tested was less well accepted than the IMUs for control of the DEKA Arm.

S110 Phantom limb pain – A correlate of maladaptive neural plasticity

Objectives The majority of limb amputees complain of phantom limb pain (PLP). The primary somatosensory cortex (S1) appears to play a key role in the perception of PLP. However, there is an ongoing debate whether (a) dysfunctional S1 reorganization or (b) preservation of S1 limb representation reflects the more valid correlate of PLP. Methods We tested groups of arm amputees perceiving or not perceiving PLP, implementing tactile stimulation of the lip (testing for reorganization) and executed phantom movements (testing for preserved representation). We further assessed prosthesis use and the users‘ experiences related to the prosthesis. Neural activity in S1 was measured using functional magnetic resonance imaging. Results Amputees with PLP exhibited larger shift of S1 lip representation compared to amputees without PLP. We found no significant S1 activity differences for the execution of phantom movements. Only for lip representation, we found that amputees using a prosthesis showed significantly less dysfunctional reorganization compared to non-users. Perceiving the prosthesis as part of the body was associated with less PLP and dysfunctional reorganization. Discussion Our results support the hypothesis that dysfunctional S1 reorganization reflects a neural correlate of PLP. Prosthesis use in general and prosthesis experiences in particular predict the presence of both dysfunctional reorganization and PLP. Conclusions Maladaptive plasticity processes are associated with PLP. Whether or not dysfunctional S1 reorganization is causally linked to PLP remains open. Significance Our findings contribute to the ongoing scientific debate on the nature of S1 alterations and its importance for the presence or absence of PLP.

Influence of the renewal of removable dentures on oral health related quality of life.

BackgroundThe renewal of removable dentures is often suggested to denture wearers subject to discomfort. However, the impact of this rehabilitation on patients’ oral health related quality of life and their removable dentures related satisfaction is still unknown. This study was aimed at assessing these patient-centered outcomes and the potential impact of different factors.MethodsA cohort of 116 patients in need of removable dental prostheses rehabilitation was recruited at a dental hospital over a period of 1 year. The subjects were separated into two groups according to their prosthesis experience (group in need of removable dentures renewal/group needing an removable dentures for the first time). Subjects were asked to answer the “Geriatric Oral Health Assessment Index” (GOHAI) and the “McGill Denture Satisfaction Instrument” before and after a prosthesis integration period (9–12 weeks).ResultsGOHAI scores were slightly higher for patients with removable dentures renewal (from 40.6 ± 10.3 to 47.1 ± 10.0, p < 0.001), independently of the type of prosthetic rehabilitation. However, the scores of the GOHAI functional field did not change. Subjects with no removable dentures experience presented an increase in their functional GOHAI score (p < 0.001). Regarding patient removable dentures related satisfaction, only the “Esthetic” (p < 0.001), “Chewing efficiency” (p < 0.001) and “Oral condition” (p < 0.01) items increased after prosthesis renewal.ConclusionsThis study showed that renewing removable dentures only moderately improved the oral health related quality of life and removable dentures related satisfaction of patients, regardless of age, gender or type of rehabilitation. Other tasks are necessary such as the analysis of physiological parameters and qualitative research on patient’s expectations.

The development and validation of a novel outcome measure to quantify mobility in the dysvascular lower extremity amputee: the amputee single item mobility measure

Objective: This study describes the development and psychometric evaluation of a novel patient-reported single-item mobility measure. Design: Prospective cohort study. Setting: Four Veteran’s Administration Medical Centers. Subjects: Individuals undergoing their first major unilateral lower extremity amputation; 198 met inclusion criteria; of these, 113 (57%) enrolled. Interventions: None. Main measures: The Amputee Single Item Mobility Measure, a single item measure with scores ranging from 0 to 6, was developed by an expert panel, and concurrently administered with the Locomotor Capabilities Index-5 (LCI-5) and other outcome measures at six weeks, four months, and 12 months post-amputation. Criterion and construct validity, responsiveness, and floor/ceiling effects were evaluated. Responsiveness was assessed using the standardized response mean. Results: The overall mean 12-month Amputee Single Item Mobility Measure score was 3.39 ±1.4. Scores for transmetatarsal, transtibial, and transfemoral amputees were 4.2 (±1.3), 3.2 (±1.5), and 2.9 (±1.1), respectively. Amputee Single Item Mobility Measure scores demonstrated “large” and statistically significant correlations with the LCI-5 scores at six weeks (r = 0.72), four months (r = 0.81), and 12 months (r = 0.86). At four months and 12 months, the correlation between Amputee Single Item Mobility Measure scores and hours of prosthetic use were r = 0.69 and r = 0.66, respectively, and between Amputee Single Item Mobility Measure scores and Trinity Amputation and Prosthesis Experience Scales functional restriction scores were r = 0.45 and r = 0.67, respectively. Amputee Single Item Mobility Measure scores increased significantly from six weeks to 12 months post-amputation. Minimal floor/ceiling effects were demonstrated. Conclusions: In the unilateral dysvascular amputee, the Amputee Single Item Mobility Measure has strong criterion and construct validity, excellent responsiveness, and does not exhibit floor/ceiling effects.

The Timed Up and Go and Two-Minute Walk Test: Exploration of a method for establishing normative values for established lower limb prosthetic users

The Timed Up and Go (TUG) and Two-Minute Walk Test (2MWT) are clinically appropriate mobility measures in amputee rehabilitation. Despite the tests being routinely performed, reference values for amputees have yet to be established. This study aimed to establish and trial a method for estimating normative values of the TUG and 2MWT for transtibial and transfemoral amputees. Thirty-seven established prosthetic users aged 40–69 years (28 unilateral transtibial amputees and nine unilateral transfemoral) performed two recorded trials of the TUG and 2MWT. Participant characteristics were collected using the Trinity Amputation and Prosthesis Experience Scale. Preliminary normative data for the TUG and 2MWT were produced for three age cohorts and the two amputee subpopulations. Poorer mobility performance with transfemoral amputation was evident for both mobility measures. Multivariate analysis displayed relationships between age, length of time with a prosthesis and performance of both tests. In conclusion, normative values for the TUG and 2MWT for transtibial and transfemoral amputees may be calculated. Preliminary results indicate that higher levels of amputation relate to poorer performance on both the TUG and 2MWT. Studies with larger samples are required to further develop these values for use in rehabilitation.

Adaptive devices in young people with upper limb reduction deficiencies: Use and satisfaction.

To evaluate use of, satisfaction with, and social adjustment with adaptive devices compared with prostheses in young people with upper limb reduction deficiencies. Cross-sectional study of 218 young people with upper limb reduction deficiencies (age range 2-20 years) and their parents. A questionnaire was used to evaluate participants' characteristics, difficulties encountered, and preferred solutions for activities, use satisfaction, and social adjustment with adaptive devices vs prostheses. The Quebec User Evaluation of Satisfaction with assistive Technology and a subscale of Trinity Amputation and Prosthesis Experience Scales were used. Of 218 participants, 58% were boys, 87% had transversal upper limb reduction deficiencies, 76% with past/present use of adaptive devices and 37% with past/present use of prostheses. Young people (> 50%) had difficulties in performing activities. Of 360 adaptive devices, 43% were used for self-care (using cutlery), 28% for mobility (riding a bicycle) and 5% for leisure activities. Prostheses were used for self-care (4%), mobility (9%), communication (3%), recreation and leisure (6%) and work/employment (4%). The preferred solution for difficult activities was using unaffected and affected arms/hands and other body parts (> 60%), adaptive devices (< 48%) and prostheses (< 9%). Satisfaction and social adjustment with adaptive devices were greater than with prostheses (p < 0.05). Young people with upper limb reduction deficiencies are satisfied and socially well-adjusted with adaptive devices. Adaptive devices are good alternatives to prostheses.

Functional and psychosocial status of Haitians who became users of lower extremity prostheses as a result of the 2010 earthquake.

The January 12, 2010 earthquake devastated Port-Au-Prince, the capital of the Republic of Haiti, and its surroundings. Among the 300,000 injured, 1,200 to 1,500 people underwent traumatic /surgical amputations. The purpose of this study was to describe the functional and psychosocial impact of prostheses users who suffered a traumatic lower-limb amputation after the earthquake of 2010 in Haiti. We recruited 140 participants in collaboration with a large health care organization in Port-au-Prince from October 2011 to May 2012. Participants underwent an evaluation of physical impairments and completed questionnaires translated into Haitian Creole. The Trinity Amputation and Prosthesis Experience Scale (TAPES), and the Locomotor Capabilities Index (LCI) were used in this study. The questionnaires were administered verbally in Haitian Creole by a trained staff. We conducted descriptive statistics and t-tests using SPSS for data analysis. Participants had a mean age of 34.9 ± 12.0; 51.4% were women; 48.6% were transfemoral amputees. The mean of TAPES general adjustment (3.65 ± 0.59) and adjust to limitation (3.67 ± 0.86) were higher than the score for the social adjustment (2.58 ± 0.49). The LCI showed over 90% of subjects were physically independent in self-care; fewer were independent walking on uneven ground or inclement weather (69%). The relatively poor social adjustment is consistent with the literature that describes limited acceptance of people with physical disabilities in Haitian society. Prostheses users in Haiti would benefit from a health delivery infrastructure that also addresses the psychosocial reintegration of individuals with physical disabilities.

Comparison of upper limb amputees and lower limb amputees: a psychosocial perspective.

Amputation of limb is essential in certain conditions; however, it may have significant impact on the patient's psychological condition. The present study investigates psychological responses of upper limb (UL) amputees versus lower limb (LL) amputees regarding prosthetic adjustment, social discomfort, depression, and body image anxiety. Traumatic major amputations of 20 upper and 38 lower extremities of 58 patients who were currently using prosthesis were included. 12 of UL amputations were of dominantly used limb. Seven of the UL amputations, and nine of the LL amputations were female. The Trinity Amputation and Prosthesis Experience Scales was used for adjustment, restriction, and satisfaction. Anxiety and depression levels were assessed using Hospital Anxiety and Depression Scale (HADS). Body image disturbance and social discomfort were assessed with Amputation Body Image Scale-Revised (ABIS-R) and Social Discomfort Score, respectively. 58 individuals with 20 UL and 38 LL amputations were included. Mean age of UL amputees was 44.76±12.26 and 49.1±14.3 years for LL amputees. Mean time of daily prosthesis use was 11.35±4.8 and 11.52±4.7h, respectively. Mean time since amputation was 35.4±14.3 and 36.05±13.6 months; length of prosthesis use time was 24.8±13.4 and 23.9±15.12 months, respectively. Social adjustment and adjustment to limitation subscales had significantly higher scores in LL amputees (p<0.001). There was statistically significant difference between mean HADS depression and anxiety scores (p<0.001). Mean total ABIS-R score indicated significantly greater body image disturbance for UL amputees (p<0.001). Well-adjusted LL prosthesis probably has better cosmetic appearance compared to that of UL prosthesis and perception of cosmetic appearance may be the key factor that leads to increased levels of body image anxiety and social discomfort. Epidemiologic and prognostic study, level III.

Goal Management Tendencies Predict Trajectories of Adjustment to Lower Limb Amputation Up to 15 Months Post Rehabilitation Discharge

ObjectivesTo explore patterns of change in positive affect, general adjustment to lower-limb amputation, and self-reported disability from rehabilitation admission to 15 months postdischarge, and to examine whether goal pursuit and goal adjustment tendencies predict either initial status or rates of change in these outcomes, controlling for sociodemographic and clinical covariates. DesignProspective cohort study with 4 time points (t1: on admission; t2: 6wk postdischarge; t3: 6mo postdischarge; t4: 15mo postdischarge). SettingInpatient rehabilitation. ParticipantsConsecutive sample (N=98) of persons aged ≥18 years with major lower-limb amputation. InterventionsNot applicable. Main Outcome MeasuresPositive affect subscale of the Positive and Negative Affect Schedule; general adjustment subscale of the Trinity Amputation and Prosthesis Experience Scales-Revised; and World Health Organization Disability Assessment Schedule 2.0. ResultsPositive affect decreased from t1 to t4 for the overall sample, whereas general adjustment increased. Self-reported disability scores remained stable over this period. Stronger goal pursuit tendencies were associated with greater positive affect at t1, and stronger goal adjustment tendencies were associated with more favorable initial scores on each outcome examined. With regard to rates of change, stronger goal pursuit tendencies buffered against decreases in positive affect and promoted decreases in self-reported disability over time, whereas stronger goal adjustment tendencies enhanced increases in general adjustment to lower-limb amputation. ConclusionsGreater use of goal pursuit and goal adjustment strategies appears to promote more favorable adjustment to lower-limb amputation over time across a range of important rehabilitation outcomes.

Influence of adjustments to amputation and artificial limb on quality of life in patients following lower limb amputation

The objectives of this study are to investigate the relationship between adjustments to amputation and artificial limb, and quality of life (QoL), and to analyse the influence of sociodemographic, medical and amputation-related factors on this relationship. Patients with unilateral and noncongenital lower limb amputation who were using artificial limb were interviewed (n=368) using structured questionnaires. The Trinity Amputation and Prosthesis Experience Scales (TAPES) were used to assess adjustments to amputation and artificial limb and the MOS Short-Form Health Survey (SF-36) was used to assess the physical (PCS) and mental (MCS) component summary of QoL. Absence of comorbidity and residual stump pain, being employed, young age, less functional restriction, being more adjusted to limitation, increased social adjustment and less restriction in athletic activity were related to better PCS scores. Absence of comorbidity and phantom limb pain, nonuse of assistive device, being more adjusted to limitation, increased social adjustment and being less functionally restricted were related to higher MCS scores. Comorbidity had a modifying effect on both PCS and MCS scores. In addition, age, being employed and residual stump pain had a modifying influence on PCS, whereas assistive device use and phantom limb pain had a modifying influence on MCS. Our findings show that TAPES subscales have a modifying effect on the associations between several background (sociodemographic and amputation characteristics) and QoL (PCS and MCS). This indicates that adjustments to amputation and artificial limb are the key determinants of QoL in individuals following lower limb amputation.

Comparison of range-of-motion and variability in upper body movements between transradial prosthesis users and able-bodied controls when executing goal-oriented tasks.

BackgroundCurrent upper limb prostheses do not replace the active degrees-of-freedom distal to the elbow inherent to intact physiology. Limited evidence suggests that transradial prosthesis users demonstrate shoulder and trunk movements to compensate for these missing volitional degrees-of-freedom. The purpose of this study was to enhance understanding of the effects of prosthesis use on motor performance by comparing the movement quality of upper body kinematics between transradial prosthesis users and able-bodied controls when executing goal-oriented tasks that reflect activities of daily living.MethodsUpper body kinematics were collected on six able-bodied controls and seven myoelectric transradial prosthesis users during execution of goal-oriented tasks. Range-of-motion, absolute kinematic variability (standard deviation), and kinematic repeatability (adjusted coefficient-of-multiple-determination) were quantified for trunk motion in three planes, shoulder flexion/extension, shoulder ab/adduction, and elbow flexion/extension across five trials per task. Linear mixed models analysis assessed between-group differences and correlation analysis evaluated association between prosthesis experience and kinematic repeatability.ResultsAcross tasks, prosthesis users demonstrated increased trunk motion in all three planes and shoulder abduction compared to controls (p ≤ 0.004). Absolute kinematic variability was greater for prosthesis users for all degrees-of-freedom irrespective of task, but was significant only for degrees-of-freedom that demonstrated increased range-of-motion (p ≤ 0.003). For degrees-of-freedom that did not display increased absolute variability for prosthesis users, able-bodied kinematics were characterized by significantly greater repeatability (p ≤ 0.015). Prosthesis experience had a strong positive relationship with average kinematic repeatability (r = 0.790, p = 0.034).ConclusionsThe use of shoulder and trunk movements by prosthesis users as compensatory motions to execute goal-oriented tasks demonstrates the flexibility and adaptability of the motor system. Increased variability in movement suggests that prosthesis users do not converge on a defined motor strategy to the same degree as able-bodied individuals. Kinematic repeatability may increase with prosthesis experience, or encourage continued device use, and future work is warranted to explore these relationships. As compensatory dynamics may be necessary to improve functionality of transradial prostheses, users may benefit from dedicated training that encourages optimization of these dynamics to facilitate execution of daily living activity, and fosters adaptable but reliable motor strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/1743-0003-11-132) contains supplementary material, which is available to authorized users.

Assessment of the Feasibility of the Nintendo Wii Balance Board as an Intervention Method For Balance Rehabilitation with Lower-limb Amputees

Lower-limb amputations have a major impact on balance and functional skills, which can be limited by rehabilitation. The Wii Balance Board (WBB) with its Wii Fit game (WFg) is often used in clinical settings with lowerlimb amputees but there is little research concerning its efficacy in improving static and dynamic balance. This study aims to assess the feasibility of using the Nintendo Wii Balance Board (WBB) and Wii Fit game (WFg) for balance rehabilitation with lower-limb amputees. A pre-/post-intervention pilot study design with no control group was used. Participants received 5 WBB and WFg rehabilitation sessions / week for 8 weeks. The length of the training sessions gradually increased from 10 to 30 minutes. Clinical outcomes were measured before (T1) and after (T2) the program and consisted of: 1) walking (L-test), 2) function and balance (Amputee Mobility Predictor [AMPPRO]), 3) satisfaction (Health Care Satisfaction Questionnaire [HCSQ]), 4) motivation (visual analog scale), and 5) quality of life (Trinity Amputation and Prosthesis Experience Scales [TAPES]). All participants (n=3) showed an improvement on all the clinical outcomes, except for the two functional tests, where one participant performed worse at T2 than T1. This pilot study demonstrated the feasibility of using the WBB and its WFg for balance rehabilitation with lower-limb amputees. Further research is needed to determine if this method is at least as effective as conventional interventions.

A prospective study of the importance of life goal characteristics and goal adjustment capacities in longer term psychosocial adjustment to lower limb amputation

Objective: To explore the life goal characteristics and goal adjustment capacities of persons with lower limb amputation on admission to rehabilitation, and to examine their efficacy as predictors of psychosocial outcomes six months post discharge. Design: Prospective, descriptive. Setting: Two specialist inpatient rehabilitation facilities in Ireland. Subjects: A consecutive sample of 64 patients with lower limb amputation. Main measures: On admission to rehabilitation, life goal characteristics (goal importance, goal disturbance) were assessed using the Goal Facilitation Index and goal adjustment capacities (goal disengagement, goal re-engagement) were measured using the Goal Adjustment Scale. The Beck Depression Inventory-II and the Trinity Amputation and Prosthesis Experience Scales-Revised assessed depressive symptomatology and psychosocial adjustment to amputation at six months post discharge. Results: The highest average importance ratings were assigned to goals associated with interpersonal relationships, independence and subjective well-being. Goals related to physical limitations and disruptions in daily activities received the highest hindrance ratings. Goal importance (β = −0.33) and goal disengagement (β = −0.29) on admission significantly predicted depressive symptomatology six months post discharge (P ≤ 0.05). Goal importance (β = 0.32), goal disturbance (β = −0.26), and goal re-engagement (β = −0.21) on admission significantly predicted general adjustment to lower limb amputation at six months post discharge (P ≤ 0.05), while goal importance (β = −0.32) and goal disturbance (β = 0.30) significantly predicted social adjustment (P ≤ 0.05). Conclusions: Life goal characteristics and goal adjustment capacities on admission to rehabilitation predicted psychosocial outcomes six months post discharge among individuals with lower limb amputation.

Adjustments to amputation and an artificial limb in lower limb amputees

Positive adjustments to amputation and an artificial limb play important roles in the rehabilitation process. To study the different facets of adjustments to amputation and an artificial limb in lower limb amputees and to assess the possible role of different background and amputation-related factors that could potentially influence these adjustments. Cross-sectional. Adult unilateral and non-congenital lower limb amputees (n = 368) met the inclusion/exclusion criteria. Face-to-face interviews were conducted using structured questionnaires including patient's background, amputation and the Trinity Amputation and Prosthesis Experience Scales. Amputees were on average satisfied with the functioning of the prosthesis, moderately psychosocially adjusted and not restricted in performing functional and social activities, except for athletic activities. Age, employment, daily use of prosthesis and assistive device use were the most important factors associated with adjustments to amputation and prosthesis, followed by gender, co-morbidity and amputation level. Evaluation of employment status and measures to curb unemployment through vocational rehabilitation and providing assistance for placement should be intrinsic to the rehabilitation programme. Future studies are envisaged to understand the underlying factors determining the extent of daily use of prosthesis and the reasons for the use of assistive devices by the amputees. Clinical relevance Proper appraisal and measures to alleviate employment and co-morbidity, related issues, routine evaluation of daily use of prosthesis and providing appropriate gait training might facilitate immediate and long-term adjustment.

Perception of Springs With Visual and Proprioceptive Motion Cues: Implications for Prosthetics

Manipulating objects with an upper limb prosthesis requires significantly more visual attention than doing the same task with an intact limb. Prior work and comments from individuals lacking proprioception indicate that conveying prosthesis motion through a nonvisual sensory channel would reduce and possibly remove the need to watch the prosthesis. To motivate the design of suitable sensory substitution devices, this study investigates the difference between seeing a virtual prosthetic limb move and feeling one's real limb move. Fifteen intact subjects controlled a virtual prosthetic finger in a one-degree-of-freedom rotational spring discrimination task. A custom haptic device was used to measure both real finger position and applied finger force, and the resulting prosthetic finger movement was displayed visually (on a computer screen) and/or proprioceptively (by allowing the subject's real finger to move). Spring discrimination performance was tested for three experimental sensory conditions-visual motion, proprioceptive motion, and visual and proprioceptive motion-using the method of constant stimuli, with a reference stiffness of 290 N/m. During each trial, subjects sequentially pressed the right index finger on a pair of hard-surfaced virtual springs and decided which was stiffer. No significant performance differences were found between the three experimental sensory conditions, but subjects perceived proprioceptive motion to be significantly more useful than visual motion. These results imply that relaying proprioceptive information through a nonvisual channel could reduce visual attention during prosthesis control while maintaining task performance, thus improving the upper limb prosthesis experience.

Reliability and construct validity of the Turkish version of the Trinity Amputation and Prosthetic Experience Scales (TAPES) in lower limb amputees

In Turkey there is no amputee-specific instrument to measure health-related quality of life in lower limb amputees. To evaluate the validity and reliability of a Turkish version of the Trinity Amputation and Prosthesis Experience Scales (TAPES). Outcome study to determine test-retest reliability and construct validity of the adapted Turkish version of the TAPES. After translation/retranslation of the TAPES, the Turkish version of the TAPES was applied to 47 amputees. A quality of life evaluation (Nottingham Health Profile), a satisfaction evaluation (Satisfaction with Prosthesis), and a functional assessment tool (Amputee Mobility Predictor) were also performed and analysed. On the basis of retesting, the Turkish version of the TAPES was observed to be reliable. The first domain of the Turkish version, which includes psychosocial adjustment, activity restriction and satisfaction with the prosthesis, was found to be valid. However, the validity of the second domain could not be analysed. The Turkish version of the multidimensional TAPES survey is valid and reliable in Turkish unilateral lower limb amputees and may be used in clinical situations to assess the needs of amputees. The Turkish version of the TAPES quality-of-life measurement tool for amputees is a valid instrument for assessing the effectiveness of rehabilitation and clinical applications.

Initial Experience of the Journey-Deuce Bicompartmental Knee Prosthesis: A Review of 36 Cases

We evaluated the effectiveness of a novel bicompartmental knee arthroplasty prosthesis for the treatment of degenerative disease affecting the medial and patellofemoral compartments. The study included 36 knees in 32 patients with a mean follow-up of 21 months. The mean Knee Society functional survey and Western Ontario McMaster Osteoarthritic Index Survey scores were 65.4 and 75.8, respectively. Thirty-one percent of patients were unsatisfied with the surgery, and 53% stated that they would not repeat the surgery. We report an overall survival rate of 86% with one catastrophically failed tibial baseplate. We conclude that this prosthesis provides inconsistent pain relief and unacceptable functional results for bicompartmental arthritis. Short-term survival of this prosthesis was unacceptably low, and therefore, we no longer implant it at our institution.

Simulating prosthetic vision: Optimizing the information content of a limited visual display

Visual prostheses for the restoration of functional vision are currently under development. To guide prosthesis research and allow for an accurate prognosis of functional gain, simulating the experience of a retinal prosthesis in healthy individuals is desirable. Current simulation paradigms lack crucial aspects of the prosthetic experience such as realistic head- and eye-position-dependent image presentation. We developed a simulation paradigm that used a head-mounted camera and eye tracker to lock the simulation to the point of fixation. We evaluated visual acuity, object recognition and manipulation, and wayfinding under simulated prosthetic vision. We explored three ways of optimizing the information content of the prosthetic visual image: Full-Field representation (wide visual angle, low sampling frequency), Region of Interest (ROI; narrow visible angle, high sampling frequency), and Fisheye (high sampling frequency in the center, progressively lower resolution toward the edges). Full-Field representation facilitated visual search and navigation, whereas ROI improved visual acuity. The Fisheye representation, designed to incorporate the benefits of both Full-Field representation and ROI, performed similarly to ROI with subjects unable to capitalize on the peripheral data. The observation that different image representation conditions prove advantageous for different tasks should be taken into account in the process of designing and testing new visual prosthesis prototypes.

An Expandable Prosthesis with Dual Cage-and-Plate Function in a Single Device for Vertebral Body Replacement: Clinical Experience on 14 Cases with Vertebral Tumors

An expandable vertebral body prosthesis with dual cage-and-plate function in a single device (JR prosthesis) was designed to test the hypothesis that this modular system can provide the biomechanical requirements for immediate and durable spine stabilization after corpectomy. Cadaver assays were performed with a stainless steal device to test fixation and adequacy to the human spine anatomy. Then, 14 patients with vertebral tumors (eight metastatic) underwent corpectomy and vertebral body replacement with a titanium-made JR prosthesis. All patients had neurological deficit, severe pain and spine instability prior to surgery. Mean pain score before surgery on a visual analog scale decreased from 7.6-3.0 points after operation (p = 0.002). All patients achieved at least one grade of improvement in the Frankel score (p = 0.003), excepting the three patients with Frankel grade A before surgery. Two patients with renal cell carcinoma died during the following 4 days after surgery. The remaining patients attained a painless and stable spine immediately, which was maintained for long periods (mean follow-up: 25.4 months). No significant infections or implant failures were registered. A nonfatal case of inferior vena cava surgical injury was observed (repaired during surgery without further complications). In conclusion, the JR prosthesis stabilizes the spine immediately after surgery and for the rest of the patients' life. To our knowledge, this is the first report on the clinical experience of any expandable vertebral body prosthesis with dual cage-and-plate function in a single device.

Trinity Amputation and Prosthesis Experience Scales

To perform a detailed psychometric analysis using both classical test theory and Rasch analysis of the three main scales of the Trinity Amputation and Prosthesis Experience Scales (TAPES) in people with a lower-limb amputation. A sample of 498 persons who were prosthesis users with a lower-limb amputation was retrospectively studied, pooled from a number of studies undertaken across the United Kingdom and Ireland in the past decade in which the TAPES had been completed as part of a postal survey. Both factor analysis techniques and Rasch analysis were performed on TAPES data. Dimensionality, item fit to the model, response category performance, and internal construct validity were assessed. Category collapsing and item removal were considered to improve the questionnaire. The analyses suggested to restructure the TAPES as follows: (a) three psychosocial adjustment subscales with a four-point rating scale (and a reworded item); (b) an activity restriction scale based on ten items with their original three-point rating scale; and (c) two satisfaction with the prosthesis subscales using a three-point rating scale. All scales and subscales showed acceptable internal consistency and ability to define a distinct hierarchy of persons along the measured construct. This study empirically identified a revised version of the TAPES (TAPES-R) with a simplified general structure and psychometrically suitable for assessing the complex experience of amputation and adjustment to a lower-limb prosthesis. Additional studies are needed to confirm and further explore its measurement properties in other samples, thereby adding clinical validity to the instrument.