Literature Review of Published Research Investigating Microprocessor-Controlled Prosthetic Knees

Abstract

Since 2009, several articles on microprocessor-controlled prosthetic knee (MPK) joint mechanisms have been published. Recent published data are generally rated as providing moderate to low levels of evidence because of structural weakness of the study designs. These weaknesses are due to low statistical power, a lack of blinding, industry funding, precise measures with no estimate of minimal clinically important difference (MCID), or subjective participant responses on questionnaires. Strong support for the advantages of MPKs is not available within this cohort of studies. Statistically significant improvements were observed in some gait measures when comparing MPKs with non-MPKs (NMPKs), but the values are not close to those of intact individuals. For measures of gait kinematics, gait kinetics, gait parameters, gait symmetry, or performance time, MPKs seem to offer marginal improvements over NMPKs in a few measures. There are few data and information on the differences between the types of MPKs currently on the market. Several of the articles in this review do provide novel outcome measures that incorporate multiple domains in biomechanics, function, and patient perception. The strongest metric in all studies is patient preference for MPKs, as opposed to technical gait metrics, objective functional improvements in mobility, or the activity of prosthetic users. This patient preference might easily be influenced by marketing or design appeal rather than objective technical or functional outcome measures. Although MPKs seem to produce minor improvements in some aspects of gait over NMPKs, the cost-benefit ratio of MPKs is not available. (J Prosthet Orthot. 2013;25:P41YP46.)KEY INDEXING TERMS: outcomes, prosthetic knee, transfemoral, limb loss, amputee, comparative effectiveness T his review focuses on 14 studies evaluating microprocessor-controlled prosthetic knees (MPKs) published between 2010 and 2012. Three of these are themselves review articles on the efficacy of MPKs for transfemoral amputees. A more comprehensive historical review is also covered by this State-of-the-Science Conference (SSC) but does not include these most recent publications. This review evaluated each included article on a range of study design and results characteristics using a hybrid approach combining established scientific methodological criteria and specific prosthetic research parameters. Unlike the formal Evidence Report associated with this SSC, this review of more recent literature did not strictly follow the evidence review guidelines published by the American Academy of Orthotists and Prosthetists. In general, prosthetics research fares poorly in formal evaluations of scientific methodological criteria. 1,2 Much of the published literature on prostheses suffers from a lack of blinding, and this is understandable because it is quite difficult to accomplish effectively, especially when attempting to blind the user. Blinding may be somewhat easier for the researchers involved in assessing prosthetic gait, and this might be a subst...

Automated Characterization of Anthropomorphicity of Prosthetic Feet Fitted to Bone-Anchored Transtibial Prosthesis

“…This threshold might appear low compared to other studies comparing prosthetic knee components suggesting that an MCID of 20% was relevant. [65] We believe a lower MCID was justified in the particular case of individuals fitted transtibial BAP given their increase proprioception due to osseoperception provided by osseointegrated fixation. [66]…”

“…Interpretation of differences in stiffness outcomes between prostheses was limited mainly because of unknown effects of confounders such as individual length of residuum, variation of position of transducer in relation to ankle joint, lack of blinding, short acclimation with Free-Flow foot, effect of foot size and footwear, specific spatial gait characteristics (e.g., speed of walking, walking base, step and stride length), kinematics (e.g., trunk bending, knee flexion, hip range of movement) and kinetics (e.g., knees and hips joint power) information. [65] By definition, the generalization of stiffness outcomes must be considered carefully giving the typical intrinsic shortcoming of a case-series study and limitations listed above. Nonetheless, this study provided initial benchmark stiffness profile involving 42% of existing population with transtibial amputation fitted with press-fit fixation worldwide.…”

Kinetics of Lower Limb Prosthesis: Automated Detection of Vertical Loading Rate

“…Altogether, the differences with M1 seemed generally low for each method based on basic algebraic interpretations. Regardless of the possible statistical significance of the differences, a more comprehensive understanding was limited as there is little evidence showing how minimal clinically important differences in vertical loading rate translate into noticeable outcomes for patients (e.g., comfort score, skin damage) as highlighted previously [55,56].…”

Development of a Government Continuous Quality Improvement Procedure for Assessing the Provision of Bone Anchored Limb Prosthesis: A Process Re-Design Descriptive Study

“…Possibilities for additional cross-sectional studies are endless, particularly for the ones correlating experience with provision of BAP accordingly to technological platform supporting CQI procedure (e.g., online forms, cloud-based CMS), provision standards of components (e.g., microprocessor prosthetic knees) and clinical outcomes (e.g., Health-related quality of life, mobility, fixation stability and integrity, injuries, infections) with different type of fixations (e.g., screw-type, pressfit). (2,(50)(51)(52)(53)(54)…”