Controversies in Lower-Extremity Amputation

Pinzur, Michael S.; Gottschalk, Frank; Pinto, Marco Antonio Guedes de Souza; Smith, Douglas G.

doi:10.2106/00004623-200705000-00028

Cited by 57 publications

(51 citation statements)

References 14 publications

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“…5 There is some controversy regarding the placement of the surgical incision. Pinzur et al 30 suggested that placing the incision directly over the anterior aspect of the distal truncated tibia can potentially produce an adherent scarring of the skin to underlying tissues 31 or insufficient cushioning of this region during load-bearing. Burgess 5 argues that the location of the incision is relatively unimportant.…”

Section: Introductionmentioning

confidence: 99%

Surgical and Morphological Factors that Affect Internal Mechanical Loads in Soft Tissues of the Transtibial Residuum

et al. 2009

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The residual limb of transtibial amputation (TTA) prosthetic users is threatened daily by pressure ulcers (PU) and deep tissue injury (DTI) caused mainly by sustained mechanical strains and stresses. Several risk factors dominate the extent of internal tissue loads in the residuum. In this study, we developed a set of three-dimensional finite element (FE) models that were variants of a patient-specific FE model, built from magnetic resonance imaging scans. The set of FE modes was utilized to assess the impact of the following risk factors on the strain/stress distribution in the muscle flap: (i) the tibial length, (ii) the tibial bevelment, (iii) a fibular osteophyte, (iv) the mechanical properties of the muscle, and (v) scarring in different locations and depths. A total of 12 nonlinear FE model configurations, representing variations in these factors, were built and solved. We present herein calculations of compression, tension and shear strains and stresses, von Mises stresses, and strain energy density averaged in critical locations in the muscle flap as well as volumes of concentration of elevated stresses in these areas. Our results overall show higher stresses accumulating in the bone proximity rather than in outlying soft tissues. The longer bone configurations spread the loads toward the external surfaces of the muscle flap. When shortening the truncated bones from 11.2 to 9.2 cm, the von Mises stresses at the distal edges of the bones were relieved considerably (by up to 80%), which indicates a predicted decreased risk for DTI. Decreasing the tibial bevelment mildly, from 52.3 degrees to 37.7 degrees caused propagation of internal stresses from the bone proximity toward the more superficial soft tissues of the residuum, thereby also theoretically reducing the risk for DTI. An osteophyte at the distal fibular end increased the strain and stress distributions directly under the fibula but had little effect (<1%) on stresses at other sites, e.g., under the tibia. Elevation of muscle stiffness (instantaneous shear modulus increase from 8.5 to 16.2 kPa), simulating variation between patients, and muscle flap contraction or spasm, showed the most substantial effect by an acute rise of the von Mises stresses at the bone proximity. The mean von Mises stresses at the bone proximity were approximately twofold higher in the contracted/spastic muscle when compared to the flaccid muscle. Locating a surgical scar in different sites and depths of the residuum had the least influence on the overall loading of the muscle flap (where stresses changed by <7%). Pending further validation by epidemiological PU and DTI risk factor studies, the conclusions of this study can be incorporated as guidelines for TTA surgeons, physical therapists, prosthetists, and the TTA patients themselves to minimize the onset of PU and DTI in this population. Additionally, the present analyses can be used to guide or focus epidemiological research of PU and DTI risk factors in the TTA population.

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Section: Introductionmentioning

confidence: 99%

Surgical and Morphological Factors that Affect Internal Mechanical Loads in Soft Tissues of the Transtibial Residuum

et al. 2009

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“…One area that most orthopaedic surgeons agree on is to preserve as much of the residual limb length as possible while allowing for sufficient clearance for prosthetic components when performing a transtibial amputation. The literature indicates that the residual limb length should be at least 10 to 12 cm with 15 to 18 cm being considered the ideal length [15]. In this study, eight of the 14 patients had residual limbs greater than 16 cm, and three patients' residual limbs were longer than 18 cm.…”

Section: Discussionmentioning

confidence: 70%

“…Current research fails to offer conclusive data supporting either the traditional amputation technique or the bone bridging technique as providing a functionally superior residual limb for transtibial amputation [14,15,19]. Pinzur et al [16] have used the Prosthesis Evaluation Questionnaire to evaluate patient-perceived outcomes between the two types of amputations.…”

Section: Introductionmentioning

confidence: 99%

Do Patients With Bone Bridge Amputations Have Improved Gait Compared With Patients With Traditional Amputations?

Kingsbury

Thesing

Collins

et al. 2014

Clinical Orthopaedics &Amp; Related Research

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Background Two surgical techniques for performing a transtibial amputation include a traditional approach and a bone bridge approach. To date, there is no conclusive evidence of superiority of either technique in terms of temporal-spatial, kinetic, and mechanical work parameters. Questions/purposes We sought to compare instrumented three-dimensional gait parameters and mechanical work measurements of patients who had undergone a traditional or bone bridge amputation at the transtibial level. Residual limb length and its effect on those functional outcomes was a secondary interest irrespective of amputation type.Methods This retrospective comparative study included 14 active-duty military men with a mean age of 25 years (range, 20-28 years). Comparisons were made between seven patients with traditional and seven patients with bone bridge amputations at the transtibial level. The patients walked at self-selected and fast paces while three-dimensional gait analysis data were collected and comparisons were made between patients with the two amputation types as well as by length of the residual limb. ResultsWith the numbers available, we observed no differences between the two surgical groups at either speed for the temporal-spatial parameters or mechanical work metrics. However, the bone bridge group did demonstrate greater rolloff vertical ground reaction force during the fast walking condition with a median 1.02% of body weight compared with 0.94% (p = 0.046), which suggests a more stable platform in terminal stance. When the two groups were combined into one to test the effect of residual limb length, the linear regression resulted in an R 2 value of 0.419 (p = 0.012), in which patients with longer residual limbs had improved F3 force values during self-selected walking. Conclusions Overall, limited functional differences were found between the two groups in this small pilot study, so a superior surgical technique could not be determined; whereas our limited sample size prevents a firm conclusion of no difference, our data can be considered hypothesisgenerating for future, larger studies. Although some evidence indicated that patients with a bone bridge have improved loading at higher speeds, a regression of all patients walking at self-selected speed indicates that as residual limb length increases, loading increases regardless of amputation type. Thus, our data suggest it is important to preserve residual limb length to allow for improved loading in terminal stance.

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“…For the average, a 6-ft.-tall patient, the optimal residual tibial length should be between 10 and 18 cm. 32 It has also been suggested that tibia lengths shorter than 8 cm benefit from a total fibulectomy and peroneal nerve resection. 33 Creation of a viable and durable soft-tissue envelope around the remaining tibia and fibula is typically the most challenging part of a BKA.…”

Section: Discussion Of Findings and Relevant Literaturementioning

confidence: 99%