Prosthetic Solutions for Active Amputees. Andreas Kannenberg, MD, PhD Executive Medical Director North America, Austin, TX, USA

Transcription

1 Prosthetic Solutions for Active Amputees Andreas Kannenberg, MD, PhD Executive Medical Director North America, Austin, TX, USA

2 Technology is progressing faster than ever before Phone and audio 25 years 2

3 Historic advancements in prosthetic technology First reference of a leg prosthesis First non-locking knee joint Single-axis foot (Angelesey Leg) Multiarticulating ankle First friction brake knee mechanisms First 4-bar knee mechanism Habermann/Schede Otto Bock introduces serial production of prosthetic exoskeletal components 484 B.C. 15th century Iron hands for knights Alt-Ruppin hand Goetz-von-Berlichingen hand Items (e.g. Swords) could be clamped into these hands. Body-powered elbow Kineplasty (Vanghetti and Ceci, 1898/1900) Shoulder harness for body-powered upper limb prosthesis Muscles power upper limb prostheses Skin-lined muscle tunnel kineplasty (Sauerbruch and ten Horn) Muscles power upper limb prostheses 3

4 Technology is progressing faster than ever before Stewart-Vickers hydraulic knee SACH foot Hydraulic stance control Mauch SNS Modular friction brake knee (3R15) Modular (endoskeletal) prosthetics Carbon fiber Energy Storage and Return (ESR) feet SAFE foot Modular 4-bar knee (3R20) Modular Titanium components Multiaxial knees (3R60, Total Knee) Rotary hydraulic knee (3R80) First MP-swing knee LASAR Posture C-Leg C-Leg Compact First powered ankle/foot First powered knee First MP-ankle/foot System hand Myobock hand and control concept Electric greifer Boston arm Utah arm Dynamic Mode Control (DMC) hand Pediatric Myo-Hand System 2000 Sensor Hand Dynamic Arm SensorHand Speed First multiarticulating hand Michelangelo Hand Andreas Kannenberg Baltimore, MD - March 28, 2012 Otto Bock HealthCare 4 I Otto Bock HealthCare

5 The clinician s challenge in everyday practice There is a plethora of prosthetic components available on the market. Ottobock s adult portfolio in the U.S.: 36 prosthetic feet and 28 prosthetic knees! 5

6 The clinician s challenge in everyday practice......is to match the physical capabilities and mobility needs of the patient with the most appropriate prosthetic components. 6

7 Prosthetic feet 7

8 What basic types of prosthetic feet are available? Solid Ankle Cushioned Heel SACH foot Stationary Attachment Flexible Endoskeleton SAFE foot = solid ankle, flexible keel Foot with single-axis ankle joint Foot with bumpers around the ankle attachment to allow for limited dorsi-/plantar flexion and medio-lateral (multiaxial) ankle movement Energy Storage and Return Foot ESR/ESAR foot 8

9 What s the evidence for prosthetic feet? Cochrane* review 26 of 348 prosthetic foot studies identified in the literature search had sufficient qualitiy to be analyzed Verdict : Insufficient evidence from high quality comparative studies for the superiority of any prosthetic foot. Low to moderate quality studies found that active transtibial and transfemoral prosthesis may benefit in walking speed and gait efficiency (at speeds >4 km/h or 1.1 m/s) from the Flexfoot (ESR) compared to the SACH foot and other conventional (non-esr) feet. *The Cochrane Collaboration is kind of the Supreme Court of evidence-based medicine. Hofstad CJ, van der Linde H, van Limbeek J, Postema K: Prescription of prosthetic ankle-foot mechanisms after lower limb amputation (Review). The Cochrane Library 2009, Issue 1. Art.No.: CD DOI: / CD pub2. Andreas Kannenberg Baltimore, MD - March 28, 2012 Otto Bock HealthCare 9

10 What can we conclude for the selection of feet? (1) SACH foot: slow walking household ambulators with high demand for late-stance stability; no or only rare need to ambulate slopes, stairs, and uneven terrain. More dynamic conventional feet (flexible keel, single-axis, multiaxial): limited community ambulators who walk faster than 0.3 m/s, walk within a limited radius around the house; occasional need to negotiate slopes, stairs, and uneven terrain. 10

11 What can we conclude for the selection of feet? (2) Carbon fiber (ESR) feet: Fast walking amputees (walking speed >4 km/h or 1 m/s); need for frequent ambulation of longer distances (> 1 km/day) and negotiation of slopes, stairs, and uneven terrain. Properties of the feet vary and depend on spring configuration spring stiffnesses and lever arms. Unfortunately, there is no perfect foot for all patients and terrains. 11

12 Prosthetic foot (conventional ESR) function Level walking stance phase Sound ankle/foot: Loading response: Passive (eccentric) plantarflexion, going into eccentric dorsiflexion Mid-stance: Neutral position, going into eccentric dorsiflexion Terminal stance: Active (concentric) plantarflexion Loading of heel spring simulates eccentric plantarflexion, the softer the heel spring the more compliant Loading of forefoot spring simulates eccentric dorsiflexion Discharge of forefoot spring simulates active plantarflexion/push-off 12

13 Prosthetic knees 13

14 Biomechanical considerations for stance control selection Controlled knee flexion during weight-bearing simulates the eccentric action of the quadriceps muscle (stretching against resistance) for lowering the body down a slope or stair. modified after: Blumentritt S: Biomechanical aspects of the Andreas indications Kannenberg of prosthetic Baltimore, knee joints. MD - March 28, 2012 I Otto Otto Bock Bock HealthCare 14 Orthopädie-Technik 2004,55(6): (Article in German)

15 Biomechanical considerations for stance control selection Controlled knee flexion during weight-bearing no knee flexion limited knee flexion unlimited knee flexion locked knee friction brake knee 4-bar polycentric knee multiaxial knee ( 5 axes) stance flexion adapter / bumper hydraulic knee modified after: Blumentritt S: Biomechanical aspects of the Andreas indications Kannenberg of prosthetic Baltimore, knee joints. MD - March 28, 2012 I Otto Otto Bock Bock HealthCare 15 Orthopädie-Technik 2004,55(6): (Article in German)

16 Friction-brake knee Benefit able to flex during swing phase more natural swing pattern and foot clearance than a locked knee Disadvantages requires full extension at heel strike no stance flexion for shock absorption 3R49/15, 3R42 3R90 / 3R92 does not allow for knee flexion at late stance (pre-swing) must be unweighted to initiate swing (unnatural gait pattern) and to sit down does not support reciprocal gait on uneven ground or slope and stair descent 16

17 4-bar knees There are 3 clinically relevant types of 4-bar knees hyperstabilized knee knee with elevated instantaneous center of rotation (ICR) voluntary control knee Radcliffe CW. Four-bar linkage prosthetic knee mechanisms: kinematics, alignment and prescription criteria. Prosthet Orthot Int 1994; 18: Andreas Kannenberg Baltimore, MD - March 28, 2012 Otto Bock HealthCare 17

18 4-bar knee with elevated instantaneous center of rotation (ICR) 4-bar knee Center of rotation at heel strike is in the knee and close to the load line (GRF) = stability is vulnerable Instantaneous center of rotation at heel strike is elevated and far more posterior to the load line (GRF) = safer and more stable Radcliffe CW. Four-bar linkage prosthetic knee mechanisms: kinematics, alignment and prescription criteria. Prosthet Orthot Int 1994; 18: Andreas Kannenberg Baltimore, MD - March 28, 2012 Otto Bock HealthCare 18

19 4-bar polycentric knee with elevated ICR Benefit(s) usually safe at heel strike shortening of calf during swing improved foot clearance 3R78 3R106 allows for knee flexion at late stance more natural and dynamic gait pattern easy knee flexion for sitting down and shortening of thigh during sitting more natural appearance Disadvantages safe only in full extension (ICR rapidly moves downward towards the knee when it flexes ) no stance flexion for shock absorption does not support reciprocal gait on uneven terrain or in slope and stair descent 19

20 Polycentric knees ( 5 bars/axes [3R60/3R62]) ICR is elevated and posterior to to the load line (GRF) 3R60/3R62 Polycentric mechanism allows for limited knee flexion during stance that makes the knee even more stable as the ICR is shifted even more posterior to the load line (GRF) Blumentritt S, Scherer HW, Wellershaus U, Michael JW: Design principles, biomechanical data and clinical experience with a polycentric knee offering controlled stance phase knee flexion: A Andreas preliminary Kannenberg report. J Prosthet Baltimore, Orthot MD - March 1997, 28, 9(1): Otto Bock HealthCare 20

21 Polycentric knee with 5 axes Additional benefits to 4-bar knee shortening of calf during swing improved foot clearance may support limited stance flexion for shock absorption allows for knee flexion at late stance more natural and dynamic gait pattern easy knee flexion for sitting down and shortening of thigh during sitting more natural appearance may support reciprocal gait on shallow slopes and sligthly uneven ground 3R60 3R62 Pheon Disadvantages requires full extension at heel strike does not support reciprocal gait on heavily uneven ground or steeper slopes and stair descent 21

22 Hydraulic knee Benefits supports stance flexion for shock absorption supports loading for sitting down supports reciprocal gait on uneven ground as well as slope and stair descent Disadvantages requires full extension at heel strike stance flexion of 5 requires stance extension dampening to prevent jerk switch mechanism between stance and swing is susceptible to unintentional switching amputee must always be alert, prepared, and able to take over control with residual limb or fall in a controlled manner 3R80 22

23 Summary: Stability and function of non-mp stance control mechanisms Stability* Function Knee flexion during weight bearing Knee mechanism(s) Terrains supported (+) or not supported (-) for negotiation with reciprocal gait No Limited Unlimited (yielding) locked knee, friction brake knee, 4-bar polycentric knee reciprocal gait on level ground - no support of stance flexion for - shock absorption - reciprocal gait on uneven terrain slope descent stair descent polycentric knees with 5 axes, stance flexion adapter / bumper reciprocal gait on level ground, stance flexion for shock absorption reciprocal gait on slightly uneven terrain and shallow slopes ( 5 ) - no support of reciprocal gait for heavily uneven terrain steeper slope (>5 ) descent stair descent fluid control (hydraulic) knees reciprocal gait on level ground, stance flexion for shock absorption reciprocal gait on uneven terrain reciprocal descent of slopes and stairs!!! Be prepared for vulnerable switching mechanism between stance and swing = risk of stumbling and falling!!! *Stability = prevention of knee collapse during level walking Stability Safety Safety = stability during level walking, + stability during walking on uneven terrains, slopes, stairs + toe clearance + stumble recovery 23

24 This is where microprocessor-controlled knees come into play... C-Leg 4 Genium / X3 C-Leg / C-Leg compact: 49 peer-reviewed English language publications Genium /X3: 14 peer-reviewed English language publications Andreas Kannenberg Baltimore, MD - March 28, 2012 Otto Bock HealthCare 24

25 Hydraulic MPK s combine safety and function and overcome their inverse relationship in NMPK s Safety reduced stumbles and falls reduced indicators for risk of falling improved balance improved confidence Function and mobility Improved negotiation of stairs, slopes, obstacles, and uneven terrain reduced cognitive demand and improved multi-tasking potential to improve overall mobility level superior patient preference and quality of life Andreas Kannenberg Baltimore, MD - March 28, 2012 Otto Bock HealthCare 25

26 Courtesy of Dale Berry, CPO, Hanger Clinic Andreas Kannenberg Baltimore, MD - March 28, 2012 Otto Bock HealthCare 26

27 Improved multi-tasking Courtesy of Dale Berry, CPO, Hanger Clinic Andreas Kannenberg Baltimore, MD - March 28, 2012 Otto Bock HealthCare 27

28 non-mpk C-leg Courtesy of Michael Leach, CPO,Ottobock Andreas Kannenberg Baltimore, MD - March 28, 2012 Otto Bock HealthCare 28

29 NMPK stance phase control decision tree (1) Yes No 29

30 NMPK stance phase control decision tree (2) Yes No Yes No Yes No 30

31 NMPK stance phase control decision tree (3) Yes No Yes No 31

32 NMPK stance phase control decision tree Yes No Yes No Yes No Yes No Yes No Yes No 32

33 Special considerations on stance phase mechanisms Knee disarticulation Consider 4-bar or multiaxial mechanisms for functional shortening during swing (=increased toe clearance) and shortening of the calf during sitting (more natural appearance) No stance flexion for shock absorption Friction-brake knees and 4-bar knees do not allow for knee stance flexion. Consider a bouncing adapter or bumper to add stance flexion for shock absorption to these knee mechanisms. 33

34 NMPK swing phase control decision tree Swing phase control one (fixed) gait speed < 0.3 m/s low to medium range of gait speeds m/s full spectrum of gait speeds > 0.8 m/s Friction Pneumatic Hydraulic Swing extension assist if full extension prior to heel strike cannot be reached reliably 34

35 What is key to rehabilitation success? The Rehab Team Physicians, nurses prosthetists, physical therapists, patient and his/her family have to work hand-in-hand. The surgeon should have an understanding of prosthetics in order to create a residual limb that supports optimal prosthetic fitting. The rehab physician should consult the prosthetists to provide a comprehensive clinical picture and learn from the prosthetist about the available prosthetic options. 35

36 What is key to rehabilitation success? The Rehab Team The prosthetist should consult with the rehab physician on all conditions that may limit a successful outcome of prosthetic fitting and rehabilitation. The prosthetist should teach the physical therapist about the features and functions of the prosthetic components. The physical therapist should have an understanding of prosthetics to be able to train the patient to operate the prosthesis in the safest und most functional way possible. 36

37 Thank you for your attention.