Skeletal changes of the amputation stump and the femur on the amputated side. A clinical investigation

Stumped by the Mystery: A Case Report of Progressive Shortening of Bone Following an Above-Knee Amputation

Several studies have investigated the anatomical adaptations in amputation stumps. In this study, we present a case report of a patient who underwent an above-the-knee amputation and, over the course of time, the length of the residual bone spontaneously shortened. The patient had undergone a total hip replacement in the same leg, and the cement mantle of the hip replacement, which could be seen within the medullary canal in the early postoperative X-rays, protruded due to bone resorption one year after the amputation. Although changes in bone microarchitecture in amputation stumps are well established, this is the first report of macroscopic changes in its actual length.

Serial Femoral Fractures in An Amputation Stump: A Case Report

We report a case of an above-knee amputee who underwent dynamic hip screw fixation for a proximal femoral fracture and then open reduction and internal fixation a few years later for a further femoral fracture in the same stump. The patient had a good outcome. We aim to discuss the challenges in decision making, surgical technique and potential complications for the patient.

BMD and bone geometry in transtibial and transfemoral amputees

Prolonged unloading of bone(s) in the residual limb after amputation may cause significant bone loss in the hip and distal bony end of the residual limb. The purpose of this study was to examine the effect of amputation on bone geometry, volumetric BMD (vBMD), and areal BMD (aBMD) by comparing the intact and residual limbs in unilateral transfemoral and transtibial amputees. Amputees (seven above-knee; seven below-knee) and two groups of nonamputee control subjects gave informed consent to participate in this study. aBMD of the dual proximal femur, lumbar spine, and total body was assessed using DXA. Bone geometry and vBMD were assessed at the distal ends of the residual limb and intact limb and at a comparable cross-sectional slice of the intact limb using pQCT (Stratec XCT 3000). There were no significant group differences in age, height, weight, physical activity, time as an amputee, hours wearing a prosthesis per day, or total body and lumbar spine BMD and BMC. There were significant side x group interactions for total hip, femoral neck, and trochanter BMD, with the amputated side having lower BMD, and differences being most severe in above-knee amputees. Total and cortical vBMD and area were significantly lower at the end of the residual limb compared with the similar slice of the intact limb for both above- and below-knee amputees. In conclusion, amputees exhibited large decrements in BMD, both at the hip and at the end of the residual limb, compared with the intact side. These lower BMD values put amputees, particularly the above-knee amputees, at increased risk for osteoporosis and fragility fractures in the hip.

Postcranial robusticity in Homo. II: Humeral bilateral asymmetry and bone plasticity

The analysis of humeral asymmetry in Recent human skeletal samples and an extant tennis-player sample documents minimal asymmetry in bone length, little asymmetry in distal humeral articular breadth, but pronounced and variable asymmetry in mid- and distal diaphyseal cross-sectional geometric parameters. More specifically, skeletal samples of normal modern Euroamericans, prehistoric and early historic Amerindians, and prehistoric Japanese show moderate (ca. 5-14%) median asymmetry in diaphyseal cross-sectional areas and polar second moments of area, whereas the tennis-player sample, with pronounced unilateral physical activity, exhibits median asymmetries of 28-57% in the same parameters. A sample of Neandertals with nonpathological upper limbs exhibits similarly low articular asymmetry but pronounced diaphyseal asymmetries, averaging 24-57%. In addition, three Neandertals with actual or possible post-traumatic upper limb alterations have the same low articular asymmetry but extremely high diaphyseal asymmetries, averaging 112-215%. These data support those from experimental work on animals, exercise programs of humans, and human clinical contexts in establishing the high degree of diaphyseal plasticity possible for humans, past and present, under changing biomechanical loading conditions. This lends support to activity-related functional interpretations of changing human diaphyseal morphology and robusticity during the Pleistocene.

The affinity of bone to hydroxyapatite and alumina in experimentally induced osteoporosis

The authors studied how bone reacts to hydroxyapatite (HAP) and alumina (Al2O3) in osteoporosis experimentally induced in a rat animal model by resection of the sciatic nerve. Sixteen and 32 weeks after resection of the sciatic nerve, implants of HAP and Al2O3 were inserted into rat tibias. The reaction of bone to HAP was compared with its reaction to Al2O3, which is bioinert, as a control. The results were analyzed using the affinity index (the length of bone directly opposed to the implant without an intervening fibrous membrane/total length of the bone-implant interface x 100%). In the rats left for 16 weeks after resection of the sciatic nerve the index values 24 weeks after insertion of HAP and Al2O3 were 96.9 +/- 2.4% (N = 8) and 75.2 +/- 22.2% (N = 8), respectively. The index value of HAP was 97.2 +/- 2.6% (N = 12) and of Al2O3 was 86.9 +/- 15.4% (N = 12) at 24 weeks after insertion, when the rats were first left for 32 weeks, after sciatic nerve resection. Bone was demonstrated to have a superior affinity to HAP, compared with Al2O3 (P less than .05).