Differences in Physical Performance Measures Among Patients With Unilateral Lower-Limb Amputations Classified as Functional Level K3 Versus K4

Published:February 03, 2018DOI:


      • Patients with limb loss were classified by an interdisciplinary health care team.
      • K3-classified patients had worse physical performance than K4-classified peers.
      • Self-reported physical function was similar between K3- and K4-classified patients.



      To determine whether differences in physical function, assessed via self-report questionnaires and physical performance tests, exist between individuals with lower-limb loss using a prosthetic device classified as a K3 versus a K4 functional level.


      Cross-sectional study.


      A university physical therapy amputee clinic.


      Participants (N=55) were included if they (1) were aged ≥18 years with a unilateral transfemoral or transtibial amputation; (2) were classified as K3 or K4 functional level; (3) completed all relevant outcome measures; and (4) were currently using a prosthesis.


      Not applicable.

      Main Outcome Measures

      Locomotor Capabilities Index (LCI), Prosthetic Evaluation Questionnaire–Mobility Section (PEQ-MS), Timed Up and Go (TUG), 10-Meter Walk Test (10MWT), Amputee Mobility Predictor (AMPPRO), and 6-Minute Walk Test (6MWT). K level was determined by group consensus based on a standardized clinical evaluation.


      After controlling for covariates, patients classified as K3 had slower TUG times (P=.002) and self-selected and fast gait speeds (P<.001), lower AMPPRO scores (P<.001), and walked shorter distances during the 6MWT (P=.003) when compared with patients classified as K4. No significant between-group differences for the LCI or PEQ-MS were found.


      Clinicians involved in prosthetic prescription may consider including the TUG, 10MWT, AMPPRO, and 6MWT during their clinical evaluations to help differentiate between individuals of higher functional mobility. The LCI and PEQ-MS may be less useful in classifying individuals as K3 versus K4 because of a ceiling effect.


      List of abbreviations:

      AMPPRO (Amputee Mobility Predictor), BMI (body mass index), CI (confidence interval), LCI (Locomotor Capabilities Index), PEQ-MS (Prosthesis Evaluation Questionnaire–Mobility Section), 6MWT (6-Minute Walk Test), 10MWT (10-Meter Walk Test), TUG (Timed Up and Go)
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