William J J Ertl

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

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.

Does Syndesmotic Injury Have a Negative Effect on Functional Outcome? A Multicenter Prospective Evaluation.

Objective: To evaluate the effect of syndesmotic disruption on the functional outcomes of Weber B, SE4 ankle fractures treated operatively. Setting: Multicenter trauma hospitals. Patients: Data were prospectively gathered during a previous, multicenter randomized trial including 242 patients (136 women, 106 men) from 9 trauma centers with operatively treated Weber B SE4 ankle fractures. There were 81 patients (35%) with syndesmotic instability confirmed intraoperatively after fibula fixation. Intervention: Functional evaluations were performed postoperatively at 6, 12, 26, and 52 weeks. The presence of symptomatic hardware and peroneal tendon discomfort was evaluated with 9–12 months of follow-up. Main Outcome Measures: Functional outcomes evaluated included Short Musculoskeletal Function Assessment (SMFA), Bother index, and American Orthopaedic Foot and Ankle Society (AOFAS) scores. The recovery curve of the 2 groups was analyzed using a mixed linear regression analysis for repeated measures and included gender and race in the model. Symptomatic hardware and peroneal tendon discomfort were compared between the 2 groups with a &khgr;2 analysis. Results: The adjusted mean linear regression analyses demonstrated that patients without a syndesmotic injury had better functional outcomes for some outcome measures. SMFA scores at 12 weeks were statistically lower in patients without syndesmotic injury (P = 0.02), but not at other visits. AOFAS scores were significantly higher (P = 0.0006), and Bother index trended toward lower results (P = 0.07) in patients without syndesmotic injury at all time points. Isolated analyses (T-tests) at 1 year demonstrated a difference in the SMFA (P = 0.04) and Bother index (P = 0.05), but not the AOFAS (P = 0.21). Men consistently demonstrated better recovery than women for all outcomes, whereas race was not significant for any measure. Symptomatic hardware and peroneal tendon irritation was not statistically different between the groups. Conclusions: The recovery curves after ankle fractures were different based on syndesmotic injury. However, the difference was at the limit of clinical significance. Syndesmotic injury has a slightly detrimental effect on outcomes of operatively treated Weber B SE4 fractures. Level of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Effect of prosthetic foot on residuum-socket interface pressure and gait characteristics in an otherwise healthy man with transtibial osteomyoplastic amputation

ABSTRACT This article elucidates the effect of prosthetic foot on the residuum-socket interface (RSI) pressure and gait characteristics in a man with transtibial osteomyoplastic amputation (TOA). The study evaluates the effect of three prosthetic feet, including 1) Renegade Foot® from Freedom Innovations (Irvine, CA), 2) Venture Foot™ from College Park (Fraser, MI), and 3) Proprio Foot® from Össur (Reykjavik, Iceland) in six gait activities: walking forward at “normal” pace, walking forward at fast pace, ascending and descending a staircase, and ascending and descending a ramp. Force resistive sensors were placed at six locations, including distal anterior end-bearing, middle posterior, and four proximal points inside the prosthetic socket, to capture real-time RSI pressures. Whereas nominal values of pressure were observed in the proximal region, greater pressure was observed at the distal anterior end-bearing region of the socket, which confirmed one of the intended outcomes of the TOA procedure. Of 36 statistical tests (t-test, p < 0.05), 35 tests (97.2%) confirmed the hypothesis that when the same prosthetic foot was used in the same gait activity, peak and mean pressures are greater at the distal anterior end-bearing location than at other locations. Furthermore, 182 of 216 (84.2%) statistical tests (t-test, significance level of 0.05) supported the hypothesis that at the same measured location during the same gait activity, different prosthetic feet result in different peak (or mean) RSI pressures. Coefficients of variation of the mean sustained pressures showed that when the gait activity was changed, each prosthetic foot affected the sustained pressure differently, even at the same measured location. Each prosthetic foot also had a direct effect on temporal gait parameters such as stance phase and gait cycle durations. These results elucidate the importance for clinicians to understand the characteristics of different prosthetic foot designs to match with the specific needs of the client with amputation.

Residual muscle contraction and residuum socket interface force in men with transtibial osteomyoplastic amputation

ABSTRACT In the transtibial osteomyoplastic amputation (TOA) technique, the distal ends of the tibia and fibula are surgically joined to form a “bone bridge” to stabilize the bony anatomy of the distal residuum. The distal-most muscles also are secured to reestablish a length-tension relationship. Unlike conventional amputation techniques in which the muscles are not secured and do not retain length-tension relationship, the TOA procedure is anticipated to allow muscles to actively contract and retain normal physiological function. In this case series, outcomes of the TOA procedure were investigated by measuring electromyography signals from the tibialis anterior and gastrocnemius muscles in the residuum and forces at the residuum socket interface (RSI) in unilateral transtibial amputees with TOA during three types of gait activities (self-paced walking, brisk 2-minute walking, and walking over a distance of 25 ft while carrying various loads). Results confirmed the presence of loadings at the distal residuum and the activity in the residuum muscles during these gaits. Furthermore, statistical analysis showed that when the distal RSI force variation was higher, the residual tibialis anterior muscle was more active compared with its activity at lower distal RSI force variation.

Transtibial Amputation Outcomes Study (TAOS): Comparing Transtibial Amputation With and Without a Tibiofibular Synostosis (Ertl) Procedure

The optimal technique for a transtibial amputation in a young, active, and healthy patient is controversial. Proponents of the Ertl procedure (in which the cut ends of the tibia and fibula are joined with a bone bridge synostosis) argue that the residual limb is more stable which confers better prosthetic fit and improved function especially among high-performing individuals. At the same time, the Ertl procedure is associated with longer operative and healing time and may be associated with a higher complication rate compared with the standard Burgess procedure. The TAOS is a prospective, multicenter randomized trial comparing 18-month outcomes after transtibial amputation using the Ertl versus Burgess approach among adults aged 18 to 60. The primary outcomes include surgical treatment for a complication and patient-reported function. Secondary outcomes include physical impairment, pain, and treatment cost.

Cross-sectional study of residuum measures during gait and work-related activities in men with transtibial amputation resulting from a traumatic event

ABSTRACT Most adults with transtibial amputation due to trauma (TTAT) are work-eligible yet are disproportionately unemployed. Inappropriate residuum muscle activity and load at the distal residuum-prosthetic socket interface (RSI) during prosthetic use are suggested contributors to employment-ending injury. The purposes of this study were to examine residuum muscle activity and RSI loads during self-paced gait, brisk gait, and carrying and to determine lift/carry capacities in 10 men with TTAT and 31 controls. A cross-sectional study design was used. Descriptive and bone health biomarker data were collected. During self-paced and brisk 2-minute walk tests, distances, step-length difference, and muscle activity (rectus femoris, tibialis anterior, gastrocnemius) were recorded. In participants with TTAT, RSI loads were simultaneously determined. Floor-to-knuckle lift and 25-ft carry capacity tests were conducted. Participants were similar in personal characteristics, biomarker values, self-paced/brisk walking step length differences, and distances walked. One participant with conventional TTAT and nine with osteomyoplastic TTAT demonstrated lower carrying (25.0 kg, p < 0.01) and lifting (28.0 kg, p < 0.05) capacities than controls did. In participants with TTAT, (1) all muscles tested were active during initial and terminal stance, (2) gastrocnemius activation was inverse to respective activation in intact/control limbs during self-paced and brisk walking, and (3) RSI loads were greater throughout self-paced and brisk gait. Authors caution that generalizations cannot be made because of sample size. Men with TTAT walked similarly in step length and distance but demonstrated lower lift and carry capacities than controls did. Future study may be warranted concerning rehabilitation strategies as well as muscle activation and RSI loading during gait based on surgical approach in men with TTAT.

Changes in Residual Limb Anthropometrics and Lift, Carry, and Timed Walking Performance in Men with Transtibial Amputation due to Trauma

Introduction Despite advances in prosthetic management and rehabilitation, otherwise healthy men with transtibial amputation (TTA) risk residuum injury during work-related activity (WRA) performance. Little is known about WRAs, perceived exertion, or residuum anthropometric changes over time in this cohort. This information may help direct longer-term considerations for those with TTA within the workforce. Materials and Methods In this preliminary study, investigators prospectively examined and compared WRA performance (floor-to-knuckle lift, 25-ft carry, self-paced, and brisk 2-minute walk tests [2MWT]), gait asymmetry (differences in step length, stride length, and cadence), report of perceived exertion (RPE), and residuum anthropometrics (length, girths) in otherwise healthy men with TTA at least 6 months after rehabilitation, during two visits, 12 months apart. Results Twenty-one participants showed little difference between visits in residuum anthropometrics or in distances walked (self-paced, brisk 2MWT; p > 0.05). All had received rehabilitation varying from time of surgery and beyond initial receipt of prosthesis (n = 8; 38%) to only upon receipt of the initial prosthesis (n = 13; 62%). However, participants reported greater exertion at visit 2 during the brisk 2MWT (0.9 RPE difference; p = 0.034) but lifted 40.4 lb more at visit 2 than at the initial visit (p = 0.034). There was a progressively larger cadence difference from visit 1 to visit 2 (increased asymmetry) during the timed self-paced walk test (p = 0.026). Conclusions Regardless of improved lift capacity or residuum anthropometric stability, this healthy male cohort with TTA demonstrated progressively worsened cadence asymmetry during self-paced 2MWT and reported increased exertion during brisk-paced 2MWT. Otherwise healthy working-age men with TTA may require continual intervention to minimize cadence asymmetry and perceived exertion, potentially reducing residuum injury risk.