A comparison of limb-socket kinematics of bone-bridging and non-bone-bridging wartime transtibial amputations.

Background: While there are proponents of both bone-bridging and non-bone-bridging transtibial amputation techniques, there is a lack of evidence describing functional differences between these two techniques. The goal of the present investigation was to objectively compare the techniques of bone-bridging and non-bone-bridging with respect to limb socket displacement during physiologic loading. Methods: Fifteen male subjects with an average age of twenty-seven years (range, twenty-two to thirty-two years) who had undergone a unilateral transtibial amputation secondary to a traumatic wartime injury were prospectively evaluated. Seven patients had undergone a bone-bridging amputation, and eight had undergone a non-bone-bridging amputation. Digital fluoroscopic video was used to measure the vertical displacement of the limb within a total-surface-bearing socket with weight-bearing from 0% to 100% of body weight. Results: There was no difference in limb-socket displacement between amputation techniques with initial loading (12.78 mm for the bone-bridging group, compared with 12.43 mm for the non-bone-bridging group; p = 0.88) or with total loading (p = 0.98). Similarly, there was no difference between suspension mechanisms in limb-socket displacement with initial loading (12.15 mm for patients with pin lock suspension, compared with 12.98 mm for those with suction sleeve suspension; p = 0.72) or with total loading (18.24 mm for patients with pin lock suspension, compared with 21.42 mm for those with suction sleeve suspension, p = 0.21). Conclusions: The current study demonstrated no difference between surgical techniques with respect to bone-socket displacement. These data provide no evidence to support statements that bone-bridging contributes to a more efficient platform in the total-surface-bearing socket.