Skip Navigation LinksHome > April 2010 - Volume 22 - Issue 2 > Assessment of Pressures Within the Prosthetic Socket of a Pe...
JPO Journal of Prosthetics & Orthotics:
doi: 10.1097/JPO.0b013e3181cca6e0
Case Report

Assessment of Pressures Within the Prosthetic Socket of a Person With Osteomyoplastic Amputation During Varied Walking Tasks

Commuri, Sesh PhD; Day, Jonathan CPO; Dionne, Carol P. PT, PhD, OCS, Cert MDT; Ertl, William J. J. MD

Free Access
Article Outline
Collapse Box

Author Information

SESH COMMURI, PhD, is affiliated with School of Electrical and Computer Engineering, Stephenson Research and Technology Center, University of Oklahoma, Norman, Oklahoma.

JONATHAN DAY, CPO, is affiliated with Department of Orthopedic Surgery and Rehabilitation, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.

CAROL DIONNE, PT, PhD, OCS, Cert MDT, is affiliated with Department of Rehabilitation Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.

WILLIAM J. J. ERTL, MD, is affiliated with Department of Orthopedics Surgery and Rehabilitation, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.

Disclosure: The authors declare no conflict of interest.

Correspondence to: Sesh Commuri, PhD, School of Electrical and Computer Engineering, Stephenson Research and Technology Center, 101 David L. Boren Boulevard, Room 1050, University of Oklahoma, Norman, OK 73019; e-mail: scommuri@ou.edu

Collapse Box

Abstract

In this article, we report the pilot evaluation of the interfacial contact forces produced inside the prosthetic socket of a transtibial “Ertl amputee” while walking at varied speeds, directions, and elevations. In addition to the contact forces, the temporal-spatial parameters for the different gaits were also studied. Although the goal of osteomyoplastic transtibial amputation, i.e., “Ertl Procedure,” is to provide an “end-bearing” limb for prosthetic wear, such “end bearing” could not be verified or quantified in the past. In this study, a sensor kit and a data acquisition system were developed to monitor the internal loads between the residual limb and prosthetic socket in a transtibial amputee. The subject, an otherwise healthy individual, had undergone right osteomyoplastic amputation. The interfacial loads within the socket and the gait parameters were evaluated during different types of gaits under normal ambulation. The study shows that although the weight was transferred almost uniformly to the proximal regions of the prosthetic socket, significant end bearing was achieved during all the tests.

The purpose of this case study was to study the interfacial contact forces produced inside the prosthetic socket by a subject's residual limb while walking at varied speeds, directions, and elevations. What was unique about this case is that the subject is a recipient of an osteomyoplastic transtibial amputation, the “Ertl procedure.”

Amputation osteomyoplasty is a technique in which the medullary canal of the amputated bone is sealed either by a periosteal sleeve or by hinging a segment of the fibula into a slot in the cut end of the tibia. This synostosis between the tibia and fibula, i.e., the “bone bridge” (Figure 1), is created to stabilize the anatomic structures within the distal-most residual limb.1 The myoplasty then provides the distal-most muscles within the anterior, superficial posterior, and lateral compartments attachment to one another, creating muscle-bone balance and stability within the residual limb.2 The goal of this procedure is to provide an “end-bearing” limb for prosthetic wear.3–5

Figure 1
Figure 1
Image Tools

In the traditional approach to amputation, loading at the distal end of the residual limb is generally avoided to minimize the occurrence of wounds and to prevent the breakdown of the residual limb.6,7 The prosthetic socket is, therefore, designed to transfer the weight to the knee and functionally unload the residual limb. Contrary to the traditional approach, in amputation osteomyoplasty, the residual limb should function as normally as possible, including the load bearing along the axial length of the bone. Such an end-bearing limb can theoretically stimulate the skin and deep tissue and reduce atrophy of the residual limb due to disuse. End bearing is also expected to reduce pain, improve sensation and blood flow, and improve walking ability and prosthetic wear.5 Many patients have proclaimed the end-bearing benefits of the osteomyoplastic transtibial amputation. However, such claims are anecdotal and have not been validated during clinical trials.

Functional evaluation of prosthetic limbs has been addressed by several researchers.8–19 Measures such as maximum ambulation time18 and metabolic analysis of oxygen consumption13 were used as metrics to assess the functional status of clinical population. The gait characteristics of normal individuals were also biomechanically compared with the gait characteristics of amputees.20 Several authors have reported small, but consistent asymmetries in the gait timing, ground reaction force profiles, and kinematics in amputees when compared with normal subjects.12,14,20 The prediction of interfacial loads between the prosthetic socket and the residual limb in transtibial amputees was attempted as a first step toward designing better fitting prosthesis.21 Finite element analysis was also used to determine contact pressures between the residual limb and the socket.22 This information was then used in the design of compliant sockets.

Although previous research reported in the literature attempted to characterize the contact pressures in the socket, the studies were performed primarily to determine the quality of the prosthetic fit and to determine any anomalies in the gait.11 These approaches while providing insight do not address the gait characteristics in an individual who has successfully undergone the Ertl procedure or do they validate the effectiveness of the surgical procedure and the prosthetic fit. This study was, therefore, designed to describe and record real-time forces produced during ambulation by the residual limb of a person who had undergone the Ertl procedure.

Back to Top | Article Outline
EXPERIMENTAL SETUP AND DATA ANALYSIS
Subject

The subject (R.K.) is a 43-year-old man who opted for a right osteomyoplastic amputation after a 2-year struggle (10 surgeries) for attempted limb salvage from a severe pilon fracture. The subject is 1.905 m tall and weighs ∼109.1 kg. He claims to be otherwise healthy without comorbidity. He gave formal consent to be a subject in this study.

RK has been using a transtibial prosthesis since January 2004 and the current prosthesis since February 2006. This prosthesis has the following components: laminated, end-bearing, total surface-bearing socket; 3-mm locking Alpha™ liner; Bulldog™ lock; Renegade™ foot; endoskeletal connectors. The socket pressure testing was conducted using his current prosthesis.

Back to Top | Article Outline
Procedures

The protocol of the study was approved by The University of Oklahoma Health Sciences Center Institutional Review Board 3 (IRB 13822) for protection of human subjects. Once formal consent was given, noninvasive instrumentation consisting of force sensors was placed within the socket of the transtibial prosthesis.

The socket was instrumented with 12 ultra-thin FlexiForce A20123 sensors that could measure both static and dynamic forces (up to 450 kg) and are thin enough to enable nonintrusive measurement. The sensors were placed in three regions (proximal third; middle third, and at the distal-most point) over four points (anterior, posterior, medial, and lateral) within the prosthetic socket (Figure 2). The A201 is a piezoresistive sensor in which resistance changes in inverse proportion to the force applied to the active sensing area of the sensor. This change in resistance can be converted to a voltage signal using an operational amplifier arrangement as shown in Figure 3. A PIC p18f2321 microcontroller-based data acquisition unit is then used to read the voltage signals representing the load sensed by each of the 12 force sensors. The contact force at each sensor is sampled at a rate of 200 Hz. The sampled values are communicated to data acquisition software running on a Laptop computer wirelessly through a Bluetooth™ interface. The instrumented package is powered through a 9 V alkaline battery and is small enough to be unobtrusively carried by the subject without affecting the gait (Figure 4).

Figure 2
Figure 2
Image Tools
Figure 3
Figure 3
Image Tools
Figure 4
Figure 4
Image Tools
Back to Top | Article Outline
Test Protocol

Data, consisting of parameters of timing (ms) of stride and step length and parameters of load (instantaneous load, peak load, average peak load, and their variances over each step), were recorded at each of the 12 sensors while the subject walked over a distance of ∼60.96 m (200 ft). The following tests were designed to study the characteristics of the gait: (T1) normal, self-paced natural forward walking; (T2) forward brisk walking; (T3) walking backward; (T4) sideways gait leading with the prosthetic limb; (T5) sideways gait leading with the intact limb; (T6) ascending one flight of stairs (22 steps); and (T7) descending one flight of stairs (22 steps).

At the end of each test run, the subject's heart rate and report of perceived exertion were monitored for subject's safety. The Borg RP Exertion is a scale for subjects' subjective reporting of perceived exertion with performance of an activity.24 The scale ranges from 6 (very light) to 20 (very, very hard) and has been found valid in attempting to quantify degree of exertion as per the subject for each activity attempted.

Back to Top | Article Outline
Data Analysis

During each test (T1–T7), the data from the sensors are transmitted to the laptop through a Bluetooth connection. The received data are then stored in a flat file on the computer. After each test is run, the sensor readings are segmented into data corresponding to each step. Routines developed in Matlab25 are then used to determine the time for each step and the loading at each sensor location for each of the test regimens. Individual sensor reading over each step was then compared to determine the maximum, minimum, and average loading and the associated variance at the sensor location for each stride over the entire test run.

Back to Top | Article Outline
EXPECTATIONS FOR THE CASE STUDY

The investigators expect to see the following:

E1. End bearing of the residual limb within the socket as recorded by the sensors.

E2. See the greatest loading in the distal anterior sensor and minimal loading in the posterior sensor during self-paced normal forward gait. Greatest expected contact forces would be detected by the anterior distal sensor during weight acceptance to early stance and the middle anterior sensor during late stance to push-off.

E3. The time for each stride would be smaller during brisk forward gait when compared with self-paced normal gait. Thus, the loading at the distal sensor would be of very short duration.

E4. During backward gait, we expect the opposite results—as stated in E2.

E5. During side to side gait, there would be constant loading in the anterior and posterior sensor readings.

E6. While ascending a set of stairs, we expect the posterior middle sensor located near to the calf muscles in the residual limb to detect the greatest force.

E7. While descending the stairs, we expect to find the greatest amount of force detected by the anterior distal sensor compared with the loading experienced at the same sensor while ascending a set of stairs.

Back to Top | Article Outline

RESULTS

The subject's heart rate was monitored throughout the data collection. Resting heart rate was 82 bpm, and ranged from 74 bpm (during backward walking) to 88 bpm (during sideways walking leading with the prosthetic limb) during the testing. The subject's reports of perceived exertion during data collection ranged from a 7 (very, very light) during forward walking to a 13 (somewhat hard). All activities tested were self-paced.

Back to Top | Article Outline
TEST T1—FORWARD GAIT (SELF-PACED)

The subject walked 47 steps in 55.8 seconds- a distance of 60.96 m (200 feet; Table 1). The forces recorded by all of the proximal sensors (anterior, posterior, medial, and lateral) were essentially equal throughout the test. The force recorded by the anterior middle sensor was the greatest force recorded of the middle sensors, followed by the mean force recorded by the lateral middle sensor. The anterior distal sensor recorded three to six times more force than the posterior, lateral, or medial areas in the distal sensor region.

Table 1
Table 1
Image Tools

The loading characteristics during forward walking demonstrated that the subject loaded the distal end of the prosthetic socket (Figure 5). The greatest force distal was recorded by the anterior distal sensor. Overall, the greatest load during this task was recorded by the middle anterior sensor.

Figure 5
Figure 5
Image Tools
Back to Top | Article Outline
TEST T2—FORWARD GAIT (BRISK PACE)

The subject walked briskly 37 steps in 38.4 seconds a distance of 60.96 m (200 feet; Table 2). The tests show that the loading increases during the weight acceptance stage and then decreases during mid-stance before increasing again during the push-off stage (Figures 6 and 7). The average time from heelstrike to toe-off is 510 milliseconds when compared with 660 milliseconds for normal gait. Similarly, the average time for each step was 887 milliseconds when compared with 940 milliseconds for normal gait. As with “typical” forward gait, the forces in the proximal sensor region were essentially equal throughout the test. The mean force recorded by the middle anterior sensor was the greatest of the middle sensor region, followed by the mean force recorded by the middle lateral sensor. The distal posterior sensor recorded three to six times more force during brisk walking than the distal anterior, distal lateral, or distal medial sensors (Table 2).

Table 2
Table 2
Image Tools
Figure 6
Figure 6
Image Tools
Figure 7
Figure 7
Image Tools

The loading characteristics during forward walking at a brisk pace demonstrated that the subject loaded the distal end of the prosthetic socket, the greatest recorded by the anterior distal sensor during stance phase [average peak load of 3.49 kg (7.67 lbs)]. The greatest load during this task was recorded by the middle posterior and middle lateral sensors during stance [6 kg (13.20 lbs) and 4.94 kg (10.86 lbs)]. The load experienced during brisk walking was also found to be higher compared with the loading during normal walk (Tables 1 and 2).

Back to Top | Article Outline
TEST T3—WALKING BACKWARD

The subject walked in reverse 52 steps in 66.6 seconds a distance of 60.96 m (200 feet). The average time from toe-down to heel-off is 720 milliseconds when compared with 660 milliseconds for normal gait. Similarly, the average time for each step was 1,210 milliseconds when compared with 940 milliseconds for normal gait. The readings from the posterior, medial, and lateral sensors in the proximal sensor region were essentially the same throughout the test. However, the proximal anterior portion recorded ∼50% more force than the other portions. In the middle sensor region, the middle anterior sensor recorded the greatest force [4.9 kg (10.79 lbs)], followed by the forces recorded by the middle lateral sensor [4.15 kg (9.13 lbs)]. The distal posterior and distal anterior sensors recorded two to four times more respective force than did the distal lateral or distal medial sensors (Table 3).

Table 3
Table 3
Image Tools

The loading characteristics while walking backward showed that end bearing was achieved at the distal end of the prosthetic socket, especially by the distal anterior and posterior sensors. The largest contact force during this task was recorded by the middle posterior, middle lateral, and at initial stance, the proximal posterior sensors. Figures 6 and 7 show that the force increases at the distal anterior sensor during weight acceptance and again during push-off. However, the loading at the middle lateral sensor is low during early stance and is the maximum at push-off (Figure 8).

Figure 8
Figure 8
Image Tools
Back to Top | Article Outline
TEST T4—SIDEWAYS GAIT LEADING WITH THE PROSTHETIC LIMB

The subject walked sideways leading with the prosthetic limb 86 steps in 100.56 seconds a distance of 200 feet. The average time from foot-down to foot-off is 570 milliseconds when compared with 660 milliseconds for normal gait. Similarly, the average time for each step was 1,140 milliseconds when compared with 940 milliseconds for normal gait. The forces recorded by all of the proximal sensors (anterior, posterior, medial, and lateral) were essentially unchanged throughout the test. The average peak force recorded by the middle anterior sensor was two to three times greater than the forces recorded by the other middle (posterior, medial, and lateral) sensors. The distal anterior sensor recorded two to eight times more force [3.74 kg (8.23 lbs)] than the other distal [0.523–0.936 kg (i.e., 1.15–2.06 lbs)] sensors.

The loading characteristics during sideways walking leading with the prosthetic limb showed that the subject exerted force at the distal end of the prosthetic socket, especially recorded at the distal anterior and distal posterior sensors. The greatest overall load during this task was recorded by the middle anterior and distal anterior sensors.

Back to Top | Article Outline
TEST T5—SIDEWAYS GAIT LEADING WITH THE INTACT LIMB

The subject walked 86 steps in 93.9 seconds a distance of 60.96 m. The average time from foot-down to foot-off is 560 milliseconds when compared with 660 milliseconds for normal gait. Similarly, the average time for each step was 1,060 milliseconds when compared with 940 milliseconds for normal gait. The forces recorded by all of the proximal sensors (anterior, posterior, medial, and lateral) were essentially equal throughout the test. The mean force recorded by the middle anterior sensor [4.86 kg (10.70 lbs)] was 1.5 to 3 times larger than the other forces recorded by other sensors in this region. The distal anterior sensor recorded two to six times more force than the distal posterior, distal lateral, or distal medial sensors.

The loading characteristics during sideways walking leading with the prosthetic limb showed that the subject exerted force at the distal end of the prosthetic socket, especially recorded at the distal anterior and distal posterior sensors. The greatest overall load during this task was recorded by the middle anterior sensor. Contrary to forward and backward gait, the loading at the distal anterior sensor and the middle anterior and lateral sensors is almost constant during sideways gait (Figures 6–8).

Back to Top | Article Outline
TEST T6—ASCENDING STAIRS

The subject reciprocally (step over step) ascended 22 steps in 39.3 seconds. The forces recorded by three of the proximal sensors (posterior, medial, and lateral) were essentially equal throughout the test (Table 6). The proximal anterior sensor recorded forces that were 50% greater than the forces recorded by the other proximal (posterior, medial, and lateral) sensors during this task. The force recorded by the middle anterior sensor was the 1.5 to 3 times greater than the other middle (posterior, medial, and lateral) sensors. The distal posterior and distal anterior sensors recorded three to six times more force than the distal lateral or distal medial sensors during this task.

Table 6
Table 6
Image Tools

The loading characteristics during ascending stairs showed that the subject exerted force at the distal end of the prosthetic socket, especially recorded at the distal anterior and distal posterior sensors. The greatest overall load during this task was recorded by the middle anterior sensor.

Back to Top | Article Outline
TEST T7—DESCENDING STAIRS

The subject reciprocally (step over step) descended 22 steps in 25.41 seconds. The forces recorded by three of the proximal sensors (posterior, medial, and lateral) were essentially equal throughout the test (Table 7). The proximal anterior sensor recorded forces that were 50% greater than the forces recorded by the other proximal (posterior, medial, and lateral) sensors during this task. The force recorded by the middle anterior sensor was the 1.5 to 3 times greater than the other middle (posterior, medial, and lateral) sensors. The distal posterior and distal anterior sensors recorded three to six times more force than the distal lateral or distal medial sensors during this task.

Table 7
Table 7
Image Tools

The loading characteristics during ascending stairs showed that the subject exerted force at the distal end of the prosthetic socket, especially recorded at the distal anterior and distal posterior sensors. The greatest overall load during this task was recorded by the middle anterior sensor.

The normal Temporal-Spatial Parameters for a male are 1.3–1.6 m/s, 100–115 steps/min, and 1.4–1.6 m, respectively. The normal stance is also supposed to be 60% to 62% of the gait cycle. Given that the subject is in the upper quartile in terms of his height, these parameters are expected to be the higher side of these ranges. However, in the study during normal forward walking, the “Stance” was seen to constitute only 54.55% of the gait cycle. Further, the walking speed was 1.09 m/s at a cadence of 99 steps/min. The stride length was 1.3 m.

Back to Top | Article Outline

DISCUSSION

PROXIMAL SENSORS

In general, the forces recorded at proximal sensors were essentially the same during all the testing except for the subjects were walking in reverse and ascending stairs during which the forces in the anterior proximal sensors recorded the greatest. This is in contrast to the standard transtibial amputation prosthetic fit in which the force is expected to be disproportionately greater within the anterior and medial portions of the socket.

Back to Top | Article Outline
MIDDLE SENSORS

In general, the anterior portion in this sensor region recorded the greatest force throughout all testing (Figure 7). This may be due to forces produced due to active contraction of the muscles of the anterior compartment (e.g., tibialis anterior) during the ambulation trials. This may be due to the myoplastic portion of the Ertl procedure in which the muscles are attached to the opposing muscle compartment. No myoplasty is performed during a standard amputation procedure.

Back to Top | Article Outline
DISTAL SENSORS: WEIGHT WAS BORNE IN THE DISTAL SENSOR REGION BY THE SUBJECT THROUGHOUT ALL TESTING

The anterior portion in all cases recorded the greatest force in this sensor region. The anterior sensor at the distal end of the residual limb is located underneath the “bone bridge” and is designed to provide end bearing in the subject. This may be evidence of muscle contraction of the muscles of the posterior compartment during the ambulation trials. This may be due to the myoplastic portion of the Ertl procedure in which the muscles are attached to the opposing muscle compartment. No myoplasty is performed during a standard amputation procedure.

The data in Tables 1 and 4–7 and the sensor readings in Figures 5–8 clearly demonstrate that end bearing was achieved in the subject (Expected Outcome E1). It is also seen that the force sensed by the distal anterior sensor increases during the weight acceptance stage and again during the push-off stage of the gait as expected (E2). In case of backward ambulation, the maximum force at the middle lateral sensor is seen at toe-off validating expectation E4. However, the forces at distal anterior and at the middle anterior and lateral sensors are unchanging in the case of sideways ambulation (E5). The mean contact time of stance was shortest for forward brisk walk (510 milliseconds) and longest for walking backward (720 milliseconds) thereby validating expectation E3.

Table 4
Table 4
Image Tools
Table 5
Table 5
Image Tools

In tests T6 and T7, contrary to expectations E6 and E7, the maximum peak load was sensed by the anterior sensors in all three regions (proximal, middle, and distal) while descending the stairs as well as when the subject was ascending the stairs. Further, the average peak load at the anterior sensors while ascending the stairs was lower than the average peak load sensed by the sensors while the subject was ascending the stairs. A possible explanation to this phenomenon is the fact that the stance time while descending the stairs was 543 milliseconds in comparison with 580 milliseconds while the subject was climbing the stairs. This short contact time was reflected in the subject quickly transferring the weight onto the intact limb in “hopping” fashion. Thus, it is conjectured that while descending the stairs, a greater portion of the weight was borne by the intact limb of the subject.

Back to Top | Article Outline
LIMITATIONS OF THE STUDY

The data and analysis presented in this article are those observed in a case study involving one individual. We have evidence of forces imparted at distinct locations inside the prosthetic socket. Some of these forces may be due to muscle contraction. However, we do not have actual evidence of muscle contraction. The data from the sensors indicate contact forces at specific points in the socket and not necessarily the total weightbearing that was achieved.

Back to Top | Article Outline

CONCLUSION

The study demonstrated that end bearing occurred during the different gait patterns studied in this experiment. There is also evidence of possible muscle contraction in the posterior compartments during all ambulation tasks of the current case study. The middle anterior sensor region gives evidence of possible muscle contraction during ambulation of the anterior compartment of the lower leg in a person with osteomyoplastic amputation. The sensor readings in the three regions (proximal, middle, and distal) indicate that the force experience by the subject depends on the nature of the gait.

Back to Top | Article Outline
SIGNIFICANCE

This case study provided preliminary information on individuals who undergo the osteomyoplastic transtibial amputation procedure. However, there is an apparent need for additional information to address issues raised and questions generated from the results of this case study.

From a prosthetic design perspective, the ability to sense the contact forces inside the socket in real time indicates the possibility of extracting these signals to control a powered prosthetic joint. The distinct characteristics of each gait pattern can then be used to modify the performance of the prosthetic joint to account for different gaits, terrain, and surface inclinations.

From a clinical perspective, our study results point out the need for future research to determine the role, if any, that the distal-most musculature in the residual limb plays during functional gait and related activities. We need to expand this line of study to include additional subjects with normal vascular and with dysvascular conditions, who have undergone the Ertl procedure compared with the standard approach to transtibial amputation. This study has set the initial stages of study necessary to study the long-term health issues related to these amputees and quantify the advantages of the osteomyoplastic procedure.

Back to Top | Article Outline

REFERENCES

1. Hussainy HA, Goesling T, Datta D, Slaeh M. Osteomyoplasty for transtibial amputation: a case report and review of the literature. J Prosthet Orthot 2004;16:2–5.

2. Dederich R. Plastic treatment of the muscles and bone in amputation surgery. A method designed to produce physiologic conditions in the stump. J Bone Joint Surg Br 1963;45:60–66.

3. Dionne CP, Ertl W, Day J. Description of physical therapy management of patients following an Ertl osteomyoplastic transtibial amputation procedure [abstract]. Phys Ther 2008:17264.

4. Dionne CP, Ertl WJ, Day J. Physical therapy management of patients following an Ertl osteomyoplastic transtibial amputation procedure. J Prosthet Orthot 2009;21:64–70.

5. Ertl JW, Ertl JP, Ertl WJ, Stokosa J. The Ertl osteomyoplastic transtibial amputation reconstruction description of technique and long term results. Available at: http://ertlreconstruction.com/documents/108.html. Accessed July 7, 2008.

6. Loon HE. Biological and biomechanical principles in amputation surgery. Prosthet Int 1959;41–57.

7. Loon HE. Below-knee amputation surgery. Artif Limbs 1963;8:86–99.

8. Binkley JM, Stratford PM, Lott SA, Riddle DL. The lower extremity functional scale (LEFS): scale development, measurement properties, and clinical application. Phys Ther 1999;79:371–383.

9. Breakey JM. Gait of unilateral below-knee amputees. Orthot Prosthet 1976;30:17–24.

10. Brooks D, Hunter JP, Parsons J, et al. Reliability of the two-minute walk test in individuals with transtibial amputation. Arch Phys Med Rehabil 2002;83:1562–1565.

11. Cheung C, Wall JC, Zelin S. A microcomputer-based system for measuring temporal asymmetry in amputee gait. Prosthet Orthot Int 1983;7:131–140.

12. Dingwell JB, Davis BL, Frazier DM. Use of an instrumented treadmill for real-time gait symmetry evaluation and feedback in normal and below-knee amputee subjects. Prosthet Orthot Int 1996;20:101–110.

13. Findley TW, Agre JC. Ambulation in adolescent with spina bifida, II: oxygen cost of mobility. Arch Phys Med Rehabil 1988;69:855–861.

14. Gailey RS, Roach KE, Applegate EB, et al. The amputee mobility predictor: an instrument to assess determinants of the lower-limb amputee's ability to ambulate. Arch Phys Med Rehabil 2002;83:613–627.

15. Pinzur MS. Outcomes from the surgeon's perspective. J Prosthet Orthot 2006;18:113–115.

16. Prince F, Winter DA, Sjonnensen G, et al. Mechanical efficiency during gait of adults with transtibial amputation: a pilot study comparing the SACH, Seattle, and Golden-Ankle prosthetic feet. J Rehabil Res Dev 1998;35:177–185.

17. Quesada PM, Pitkin M, Colvin J. Biomechanical evaluation of a prototype foot/ankle prosthesis. IEEE Trans Rehabil Eng 2000;8:156–159.

18. Skinner HB, Effeney DJ. Gait analysis in amputees. Am J Phys Med 1985;64:82–89.

19. Smith DG. Special challenges in outcome studies for amputation surgery and prosthetic rehabilitation. J Prosthet Orthot 2006;18:116–118.

20. Boda W, Findley T, Tapp W, et al. Proceedings of the 1993 IEEE Nineteenth Annual Northeast Bioengineering Conference; Newark, NJ. 1993:217–218.

21. Amali R, Noroozi S, Vinney J, et al. Predicting interfacial loads between the prosthetic socket and the residual limb for below-knee amputees—a case study. Strain 2006;42:3–10.

22. Faustini MC, Neptune RR, Crawford RH. The quasi-static response of compliant prosthetic sockets for transtibial amputees using finite element methods. Med Eng Phy 2006;28:114–121.

23. A201 FlexiForce sensor, Standard & Custom OEM Force Sensing Solutions. Available at: http://www.tekscan.com/flexiforce/flexiforce.html. Accessed January 26, 2009.

24. Borg GAV. Psychophysical bases of perceived exertion. Med Sci Sports Exerc 1982;14:327–405.

25. The Mathworks Inc., 3 Apple Hill Drive, Natick, MA 01760-2098. Available at: http://www.mathworks.com. Accessed December 9, 2009.

KEY INDEXING TERMS: gait analysis; temporal-spatial parameters; interfacial pressures; transtibial amputee; prosthetic socket; osteomyoplasty

© 2010 American Academy of Orthotists & Prosthetists

Login

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.