Upper Limb Prosthetic Patients’ Optimal Results Revealed with New Assessment Tool

by Arm Dynamics, on Feb 1, 2019 12:01:52 PM

A novel outcome measure---the Capacity Assessment of Prosthetic Performance for the Upper Limb (CAPPFUL)---has been psychometrically validated and the results published in a peer-reviewed journal. Developed by the clinical team at Arm Dynamics, it is the first comprehensive assessment tool designed exclusively to measure upper limb prosthetic performance.

What makes the CAPPFUL a pivotal outcome measure is its capacity to enable an upper limb prosthetic patient to reach their maximum rehabilitation potential. It measures specific performance domains and the overall performance of a functional upper limb prosthetic device at any amputation level, enabling the rehabilitation team to:

  • evaluate how the fit, form and function of the prosthesis affects the patient’s control for functional use
  • clearly identify functional deficits
  • detect the need for modifications to the treatment plan or prosthetic components
  • utilize objective data to inform prescriptive decisions
  • bolster evidence-based practices in patient care
  • provide essential information for insurance reimbursement justification

Outcome Measures: CAPPFUL Concept and Scoring

The CAPPFUL is comprised of 11 commonplace functional tasks (unilateral and bilateral) and is objectively scored by an upper limb prosthetic clinical therapy specialist. Each task is individually timed, and the entire assessment takes 25-35 minutes. Patient given the CAPPFUL testThe scoring mechanism for CAPPFUL uses a 0-88 point scale, with 88 being equivalent to the performance of a sound upper limb and hand. The highest possible score of 88 points indicates that all 11 tasks were completed as directed with no deficits in prosthesis design, fit, function, user skill or related body mechanics. Since there is no current prosthetic terminal device or sensory technology to match that of the human hand, patient scores are expected to be less than 88 points.

In addition to providing an overall performance score, CAPPFUL scoring also results in a nuanced evaluation of the factors impacting functional use of a prosthesis. This is achieved by scoring five key domains associated with the patient’s ability to integrate the prosthesis into their life:

  1. Control skills
  2. Component utilization
  3. Maladaptive compensatory movement
  4. Adaptive compensatory movement
  5. Task completion

Assessment of these domains allows CAPPFUL to identify which specific factors impact prosthetic integration, and can objectively inform revisions to the rehabilitation plan.

Patients are scored on the CAPPFUL at milestones in their upper limb prosthetic rehabilitation, or anytime there is a change in prosthetic components or the rehabilitation plan. When scoring indicates functional deficits with the prosthesis performance, the patient’s treatment plan shifts to include one or more of these interventions:

  • additional prosthetic training with a therapist
  • adjustment of the existing components
  • a new prescriptive recommendation to meet the user’s current capabilities
  • modification to prosthesis fit

The CAPPFUL provides an objective, evidenced-based report to help referral sources and payers understand how prosthetic intervention returns function for their patients.

CAPPFUL Assists with and Documents Significant Functional Improvement

The following data sample from a recent Arm Dynamics patient shows how the CAPPFUL can be used to objectively demonstrate progress in the level of proficiency in the functional use of a prosthesis. This patient is a 58-year-old male with a left transradial amputation due to a workplace crush and burn accident. He was fit with an AxonHook, an AxonRotator wrist (Ottobock), and a manual flexion wrist. He received prosthetic training from an upper limb prosthetic clinical therapy specialist. CAPPFUL test patientThe progression of CAPPFUL scores below illustrates how use of the assessment enabled this patient to reach his optimal functional outcome. The scoring scale starts at 0 and ends at 88 points, which is equivalent to the performance of a sound upper limb and hand. This patient’s initial score was 0 because he was unable to grasp the items included in the assessment without using a prosthesis. After being fit and trained with a preparatory prosthesis, his CAPPFUL score was 47.5, and functional issues were identified and addressed. With his definitive prosthesis, the score increased to 57. After six months of wearing the definitive prosthesis, his score increased to 73.5. His final score, which was assessed after the patient received a custom-fit socket and frame replacement, was 79.5 out of 88 possible points. CAPPFUL Progression ChartWithout utilizing the CAPPFUL, the patient’s improvement in the functional use of his prosthesis may have stalled at 47-57 points, as represented by the scores he received using the preparatory and definitive prostheses. However, the two subsequent CAPPFUL assessments identified any lingering functional challenges, and the treatment plan was modified to resolve these issues by adjusting the prosthesis and increasing targeted training. As a direct result of these interventions, the patient was able to achieve 90.34% of the performance of a sound limb!

New Upper Limb Prosthetic Technologies Require Patient-Specific Outcome Measure Tools

The Arm Dynamics clinical team has been collecting evidence-based data as a standard of care for more than ten years through a combination of performance-based and patient-perspective assessments. While this has provided objective, scientific evidence of the positive functional benefits of upper limb prosthetic rehabilitation, the industry standard outcome measures prior to CAPPFUL are limited because they:

  • don’t adequately consider the impact of new and emerging upper limb prosthetic technology
  • are designed primarily for people with injuries to the upper limb, not for those using an upper limb prosthesis
  • don’t address prosthesis design, training and component capabilities within one measurement tool

Introducing a new, validated outcome measure that’s specific to this patient population was essential to support evidence-based practices in patient care and insurance reimbursement justification.

Optimizing Upper Limb Prosthetic Outcomes

The Capacity Assessment of Prosthetic Performance for the Upper Limb (CAPPFUL) was designed to assess the performance of any functional upper limb prosthesis and ensure that these uniquely challenged patients have the opportunity to reach their maximum rehabilitation potential. The Arm Dynamics team is eager to provide specialized resources that support the work of prosthetists, physicians, nurse case managers, occupational and physical therapists, and insurance reimbursement specialists and their patients. 

AD patient successfully working in warehouse


Arm Dynamics is a leader in the upper limb prosthetics industry. Our clinical team regularly contributes their knowledge and expertise to research collaborations and scholarly publications. Publication results displayed here cover a broad range of scholarly work.

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