Cumulative loading increases and loading asymmetries persist during walking for people with a transfemoral bone-anchored limb.

BACKGROUND: A bone-anchored limb (BAL) is an alternative to a traditional socket-type prosthesis for people with transfemoral amputation. Early laboratory-based evidence suggests improvement in joint and limb loading mechanics during walking with a BAL compared to socket prosthesis use. However, changes in cumulative joint and limb loading measures, which may be predictive of degenerative joint disease progression, remain unknown. RESEARCH QUESTION: Do cumulative total limb and hip joint loading during walking change using a BAL for people with unilateral transfemoral amputation, compared to prior socket prosthesis use? METHODS: A case-series cohort of eight participants with prior unilateral transfemoral amputation who underwent BAL hardware implantation surgery were retrospectively analyzed (4 M/4 F; BMI: 27.7 ± 3.1 kg/m2; age: 50.4 ± 10.2 years). Daily step count and whole-body motion capture data were collected before (using socket prosthesis) and one-year after BAL hardware implantation. Cumulative total limb and hip joint loading and between-limb loading symmetry metrics were calculated during overground walking at both time points and compared using Cohen's d effect sizes. RESULTS: One year after BAL hardware implantation, participants demonstrated bilateral increases in cumulative total limb loading (amputated: d = -0.65; intact: d = -0.72) and frontal-plane hip moment (amputated: d = -1.29; intact: d = -1.68). Total limb loading and hip joint loading in all planes remained asymmetric over time, with relative overloading of the intact limb in all variables of interest at the one-year point. SIGNIFICANCE: Despite increases in cumulative total limb and hip joint loading, between-limb loading asymmetries persist. Habitual loading asymmetry has been implicated in contributing to negative long-term joint health and onset or progression of degenerative joint diseases. Improved understanding of methods to address habitual loading asymmetries is needed to optimize rehabilitation and long-term joint health as people with transfemoral amputation increase physical activity when using a BAL.

Dynamic gait stability and stability symmetry for people with transfemoral amputation: A case-series of 19 individuals with bone-anchored limbs.

For some individuals with severe socket-related problems, prosthesis osseointegration directly connects a prosthesis to the residual limb creating a bone-anchored limb (BAL). We compared dynamic gait stability and between-limb stability symmetry, as measured by the Margin of Stability (MoS) and the Normalized Symmetry Index (NSI), for people with unilateral transfemoral amputation before and one-year after BAL implantation. The MoS provides a mechanical construct to assess dynamic gait stability and infer center of mass and limb control by relating the center of mass and velocity to the base of support. Before and one-year after BAL implantation, 19 participants walked overground at self-selected speeds. We quantified dynamic gait stability anteriorly and laterally at foot strike and at the minimum lateral MoS value. After implantation, we observed decreased lateral MoS at foot strike for the amputated (MoS mean(SD) %height; pre: 6.6(2.3), post: 5.9(1.3), d = 0.45) and intact limb (pre: 6.2(1.2), post: 5.8(1.0), d = 0.38) and increased between-limb MoS symmetry at foot strike (NSI mean(SD) %; anterior-pre: 10.3(7.3), post: 8.4(3.6), d = 0.23; lateral-pre: 18.8(12.4), post: 12.4(4.9), d = 0.47) and at minimum lateral stability (pre: 28.1(18.1), post: 19.2(6.8), d = 0.50). Center of mass control using a BAL resulted in dynamic gait stability more similar between limbs and may have reduced the adoption of functional asymmetries. We suggest that improved between-limb MoS symmetry after BAL implantation is likely due to subtle changes in individual limb MoS values at self-selected walking speeds resulting in an overall positive impact on fall risk through improved center of mass and prosthetic limb control.

The biomechanical influence of transtibial Bone-Anchored limbs during walking.

Individuals with unilateral transtibial amputation (TTA) using socket prostheses demonstrate asymmetric joint biomechanics during walking, which increases the risk of secondary comorbidities (e.g., low back pain (LBP), osteoarthritis (OA)). Bone-anchored limbs are an alternative to socket prostheses, yet it remains unknown how they influence multi-joint loading. Our objective was to determine the influence of bone-anchored limb use on multi-joint biomechanics during walking. Motion capture data (kinematics, ground reaction forces) were collected during overground walking from ten participants with unilateral TTA prior to (using socket prostheses) and 12-months after bone-anchored limb implantation. Within this year, each participant completed a rehabilitation protocol that guided progression of loading based on patient pain response and optimized biomechanics. Musculoskeletal models were developed at each testing timepoint (baseline or 12-months after implantation) and used to calculate joint kinematics, internal joint moments, and joint reaction forces (JRFs). Analyses were performed during three stance periods on each limb. The between-limb normalized symmetry index (NSI) was calculated for joint moments and JRF impulses. Discrete (range of motion (ROM), impulse NSI) dependent variables were compared before and after implantation using paired t-tests with Bonferroni-Holm corrections while continuous (ensemble averages of kinematics, moments, JRFs) were compared using statistical parametric mapping (p < 0.05). When using a bone-anchored limb, frontal plane pelvic (residual: pre = 9.6 ± 3.3°, post = 6.3 ± 2.5°, p = 0.004; intact: pre = 10.2 ± 3.9°, post = 7.9 ± 2.6°, p = 0.006) and lumbar (residual: pre = 15.9 ± 7.0°, post = 10.6 ± 2.5°, p = 0.024, intact: pre = 17.1 ± 7.0°, post = 11.4 ± 2.8°, p = 0.014) ROM was reduced compared to socket prosthesis use. The intact limb hip extension moment impulse increased (pre = -11.0 ± 3.6 Nm*s/kg, post = -16.5 ± 4.4 Nm*s/kg, p = 0.005) and sagittal plane hip moment impulse symmetry improved (flexion: pre = 23.1 ± 16.0 %, post = -3.9 ± 19.5 %, p = 0.004, extension: pre = 29.2 ± 20.3 %, post = 8.7 ± 22.9 %, p = 0.049). Residual limb knee extension moment impulse decreased compared to baseline (pre = 15.7 ± 10.8 Nm*s/kg, post = 7.8 ± 3.9 Nm*s/kg, p = 0.030). These results indicate that bone-anchored limb implantation alters multi-joint biomechanics, which may impact LBP or OA risk factors in the TTA population longitudinally.

Lumbopelvic movement coordination during walking improves with transfemoral bone anchored limbs: Implications for low back pain.

BACKGROUND: Low back pain (LBP) is more prevalent in patients with transfemoral amputation using socket prostheses than able-bodied individuals, in part due to altered spinal loading caused by aberrant lumbopelvic movement patterns. Early evidence surrounding bone-anchored limb functional outcomes is promising, yet it remains unknown if this novel prosthesis influences LBP or movement patterns known to increase its risk. RESEARCH QUESTION: How are self-reported measures of LBP and lumbopelvic movement coordination patterns altered when using a unilateral transfemoral bone-anchored limb compared to a socket prosthesis? METHODS: Fourteen patients with unilateral transfemoral amputation scheduled to undergo intramedullary hardware implantation for bone-anchored limbs due to failed socket use were enrolled in this longitudinal observational cohort study (7 F/7 M, Age: 50.2±12.0 years). The modified Oswestry Disability Index (mODI) (self-reported questionnaire) and whole-body motion capture during overground walking were collected before (with socket prosthesis) and 12-months following bone-anchored limb implantation. Lumbopelvic total range of motion (ROM) and continuous relative phase (CRP) segment angles were calculated during 10 bilateral gait cycles. mODI, total ROM, CRP and CRP variabilities were compared between time points. RESULTS: mODI scores were significantly reduced 12-months after intramedullary hardware implantation for the bone-anchored limb (P = 0.013). Sagittal plane trunk and pelvis total ROM during gait were reduced after implantation (P = 0.001 and P < 0.001, respectively). CRP values were increased (more anti-phase) in the sagittal plane during single limb stance and reduced (more in-phase) in the transverse plane during pre-swing of the amputated limb gait cycle (P << 0.001 and P = 0.029, respectively). No differences in CRP values were found in the frontal plane. SIGNIFICANCE: Decreases in mODI scores and lumbopelvic ROM, paired with the changes in lumbopelvic coordination, indicate that bone-anchored limbs may reduce LBP symptoms and reduce compensatory movement patterns for people with unilateral transfemoral amputation.

How Comprehensive and Efficient Are Patient-Reported Outcome Measures for Individuals with Lower Extremity Amputation Undergoing Implantation of Osseointegrated Bone Anchored Limbs?

¼ Patient-reported outcome measures (PROMs) are essential for measuring quality and functional outcomes after implantation of osseointegrated bone anchored limbs for patients with lower extremity amputation.¼ Using a novel assessment criterion with 8 domains, this study assessed all commonly used PROMs for their efficiency and comprehensiveness.¼ Comprehensiveness was scored according to the presence or absence of PROM questions related to these 8 domains (maximum score = 60): mobility (15 items), prosthesis (14 items), pain (10 items), psychosocial status (10 items), independence/self-care (4 items), quality of life/satisfaction (4 items), osseoperception (1 item), general information (1 item), and vitality (1 item).¼ The efficiency scores were calculated by dividing the comprehensiveness score by the total number of questions answered by the patients with higher scores being deemed more efficient.¼ The most comprehensive PROMs were Orthotics and Prosthetics User's Survey-Lower Extremity Functional Status (OPUS-LEFS) (score = 36), Prosthesis Evaluation Questionnaire (PEQ) (score = 31), and Questionnaire for Persons with a Transfemoral Amputation (score = 27).¼ The most efficient PROMs were the OPUS-LEFS (score = 1.8) and European Quality of Life (score = 1.4).

The Amputated Limb Gluteus Medius is Biomechanically Disadvantaged in Patients with Unilateral Transfemoral Amputation.

Patients with transfemoral amputation (TFA) are at an increased risk of secondary musculoskeleteal comorbidities, primarily due to asymmetric joint loading. Amputated limb muscle weakness is also prevalent in the TFA population, yet all factors that contribute to muscle strength and thus joint loading are not well understood. Our objective was to bilaterally compare gluteus medius (GMED) muscle factors (volume, fatty infiltration, moment arm) that all contribute to joint loading in patients with TFA. Quantitative magnetic resonance (MR) images of the hip were collected from eight participants with unilateral TFA (2M/6F; age: 47.3 ± 14.7 y/o; BMI: 25.4 ± 5.3 kg/m2; time since amputation: 20.6 ± 15.0 years) and used to calculate normalized GMED muscle volume and fatty infiltration. Six participants participated in an instrumented gait analysis session that collected whole-body kinematics during overground walking. Subject-specific musculoskeletal models were used to calculate bilateral GMED (anterior, middle, posterior) moment arms and frontal plane hip joint angles across three gait cycles. Differences in volume, fatty infiltration, hip adduction-abduction angle, and peak moment arms were compared between limbs using paired Cohen's d effect sizes. Volume was smaller by 36.3 ± 18.8% (d = 1.7) and fatty infiltration was greater by 6.4 ± 7.8% (d = 0.8) in the amputated limb GMED compared to the intact limb. The amputated limb GMED abduction moment arms were smaller compared to the intact limb for both overground walking (anterior: d = 0.9; middle: d = 0.1.2) and during normal range of motion (anterior: d = 0.8; middle: d = 0.8) while bilateral hip adduction-abduction angles were similar during overground walking (d = 0.5). These results indicate that in patients with TFA, the amputated limb GMED is biomechanically disadvantaged compared to the intact limb, which may contribute to the etiology of secondary comorbidities. This population might benefit from movement retraining to lengthen the amputated limb GMED abduction moment arm during gait.

Daily steps and stepping cadence increase one-year following prosthesis osseointegration in people with lower-limb amputation.

PURPOSE: People with lower-limb loss participate in less physical activity than able-bodied individuals, which increases the mortality risk and incidence of metabolic syndromes. This study evaluated the effect of lower-limb prosthesis osseointegration on physical activity, including daily steps and stepping cadence. METHODS: Free-living walking activity was assessed from 14 patients scheduled to undergo prosthesis osseointegration at two time points (within 2 weeks prior to osseointegration surgery and 12-months following). Daily step count, stepping time, number of walking bouts, average step cadence per bout, maximum step cadence per bout, and time spent in bands of step cadence were compared before and after osseointegration. RESULTS: Twelve months after prosthesis osseointegration, participants increased daily steps, daily stepping time, average step cadence, and maximum cadence per walking bout compared to pre-osseointegration. CONCLUSIONS: Participants engaged in more daily steps, higher stepping cadence, and longer bouts at higher cadence one year following osseointegration compared to when using a socket prosthesis. As a novel intervention that is becoming more common, it is important to understand walking activity outcomes as these are critical for long-term health.

People with lower-limb loss participate in less physical activity than able-bodied individuals, which increases the mortality risk and incidence of metabolic syndromes.Daily step count, walking bouts, and step cadence during free-living walking activity are promising measures to capture physical functional performance in patients with lower-limb amputation.This study shows that patients with osseointegrated prostheses increase their stepping activity, including daily steps, number of bouts, and stepping cadence compared to when using a socket prosthesis, which has positive implications on overall patient health.As a novel intervention that is becoming more common, it is important for clinicians, patients, and researchers to understand expectations for walking activity outcomes as a critical factor in long-term patient health after prosthesis osseointegration.

Unilateral transfemoral osseointegrated prostheses improve joint loading during walking.

People with unilateral transfemoral amputation using socket prostheses are at increased risk for developing osteoarthritis in both the residual hip and intact lower-limb joints. Osseointegrated prostheses are a surgical alternative to socket prostheses that directly attach to the residual femur via a bone-anchored implant, however their multi-joint loading effect is largely unknown. Our objective was to establish how osseointegrated prostheses influence joint loading during walking. Motion capture data (kinematics, ground reaction forces) were collected from 12 participants at baseline, with socket prostheses, and 12-months after prosthesis osseointegration during overground walking at self-selected speeds. Subject-specific musculoskeletal models were developed at each timepoint relative to osseointegration. Internal joint moments were calculated using inverse dynamics, muscle and joint reaction forces (JRFs) were estimated with static optimization. Changes in internal joint moments, JRFs, and joint loading-symmetry were compared using statistical parametric mapping (p≤ 0.05) before and after osseointegration. Amputated limb hip flexion moments and anterior JRFs decreased during terminal stance (p = 0.002, <0.001; respectively), while amputated limb hip abduction moments increased during mid-stance (p < 0.001), amputated hip rotation moment changed from internal to external throughout early stance (p < 0.001). Intact limb hip extension and knee flexion moments (p = 0.028, 0.032; respectively), superior and resultant knee JRFs (p = 0.046, 0.049; respectively) decreased during the loading response following prosthesis osseointegration. These results may indicate that the direct loading transmission of these novel prostheses create a more typical mechanical environment in bilateral joints, which is comparable with loading observed in able-bodied individuals and could decrease the risk of development or progression of osteoarthritis.

Prophylactic Intrawound Antibiotics Significantly Reduce the Risk of Deep Infections in Fracture Fixation: Subgroup Meta-analyses of the Type of Fracture, Antibiotics, and Organism.

OBJECTIVES: To analyze the efficacy of subgroups of various intrawound local antibiotics in reducing the rate of fracture-related infections. DATA SOURCES AND STUDY SELECTION: PubMed, MEDLINE via Ovid, Web of Science, Cochrane database, and Science Direct were searched for articles in English on July 5, 2022, and December 15, 2022. STUDY SELECTION: All clinical studies comparing the incidence of fracture-related infection between the administration of prophylactic systemic and topical antibiotics in fracture repair were analyzed. DATA EXTRACTION: Cochrane collaboration's assessment tool and the methodological bias and the methodological index for nonrandomized studies were used to detect bias and evaluate the quality of included studies, respectively. DATA SYNTHESIS: RevMan 5.3 software (Nordic Cochrane Centre, Denmark) was used to conduct the meta-analyses and generate forest plots. CONCLUSIONS: From 1990 to 2021, 13 studies included 5309 patients. Nonstratified meta-analysis showed that intrawound administration of antibiotics significantly decreased the overall incidence of infection in both open and closed fractures, regardless of the severity of open fracture and antibiotics class [OR = 0.58, ( P = 0.007)] [OR = 0.33, ( P < 0.00001)], respectively. The stratified analysis revealed that prophylactic intrawound antibiotics significantly lowered infection rate in open fracture patients with Gustilo-Anderson type I (OR = 0.13, P = 0.004), type II (OR = 0.29, P = 0.0002), type III (OR = 0.21, P < 0.00001), when either tobramycin PMMA beads (OR = 0.29, P < 0.00001) or vancomycin powder (OR = 0.51, P = 0.03) was applied. This study demonstrates prophylactic administration of intrawound antibiotics significantly decreases the overall incidence of infection in all subgroups of surgically fixated fractures but does not affect the patient's length of hospital stay. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Above knee socket prosthesis use changes proximal femur morphology.

Patients with transfemoral amputation (TFA) are up to six times more likely to develop hip osteoarthritis (OA) in either or both the intact and residual limb, which is primarily attributed to habitually altered joint loading due to compensatory movement patterns. However, joint loading patterns differ between limbs, which confounds the understanding of loading-induced OA etiology across limbs. It remains unknown if altered loading due to amputation results in bony shape changes at the hip, which is a known etiological factor in the development of hip OA. Retrospective computed tomography images were collected of the residual limb for 31 patients with unilateral TFA (13F/18M; age: 51.7 ± 9.9 y/o; time since amputation: 13.7 ± 12.4 years) and proximal femur for a control group of 29 patients (13F/16M; age: 42.0 ± 12.27 years) and used to create 3D geometries of the proximal femur. Femoral 3D geometric variation was quantified using statistical shape modeling (SSM), a computational tool which placed 2048 corresponding particles on each geometry. Independent modes of variation were created using principal component analysis. 2D radiographic measures of the proximal femur, including common measures such as α-angle, head neck offset, and neck shaft angle, were quantified on digitally reconstructed radiographs (DRRs). SSM results were then compared to 2D measures using Pearson correlation coefficients (r). Two-sample t-tests were used to determine if there were significant differences between the TFA and control group means of 2D radiographic measurements (p < 0.05). Patients with TFA had greater femoral head asphericity within the SSM, which was moderately correlated to head-neck offset (r = -0.54) and α-angle (r = 0.63), as well as greater trochanteric torsion, which was strongly correlated to the novel radiographic measure of trochanteric torsion (r = -0.78), compared to controls. For 2D measures, the neck-shaft angle was smaller in the TFA group compared to the control group (p = 0.01) while greater trochanter height was larger in the TFA group compared to the control group (p = 0.04). These results indicate altered loading from transfemoral prosthesis use changes proximal femur bony morphology, including femoral head asphericity and greater trochanter changes. Greater trochanter morphologic changes, though not a known factor to OA, affect moment arm and line of action of the primary hip abductors, the major muscles which contribute to joint loading and hip stability. Thus, chronic altered loading of the amputated limb hip, whether under- or overloading, results in bony changes to the proximal femur which may contribute to the etiological progression and development of OA.

Changes in lower extremity joint moments one-year following osseointegration in individuals with Transfemoral lower-limb amputation: A case series.

BACKGROUND: Dissatisfaction with socket prostheses has led to the development of bone-anchored prostheses through osseointegration for people with transfemoral amputation, eliminating the need for a prosthetic socket. Gait deviations of transfemoral prosthesis users may be linked to increased risk of osteoarthritis, and it remains unknown if gait biomechanics change following osseointegration. The purpose of this case series was to evaluate the longitudinal changes in joint kinetics one year post-osseointegration in patients with transfemoral amputation during walking. METHODS: Knee, hip, and trunk internal moments were evaluated in the prosthetic and intact limbs during walking at a self-selected speed in four participants pre- and one-year post-osseointegration. Longitudinal changes were quantified using the percent change (%∆) in peak joint moments between the two time points and Cohen's d (d) effect size was used to determine the magnitude of effect on joint moments during walking one year following osseointegration. FINDINGS: Participants demonstrated increased peak knee extension moment (224 ± 308%∆, d = -1.31) in the prosthetic limb, while demonstrating reduced peak knee extension moment (-43 ± 34%∆, d = 1.82) in the intact limb post-osseointegration. Participants demonstrated bilateral reduction of peak hip extension moment (prosthetic: -22 ± 37%∆, d = 0.86; intact: -29 ± 10%∆, d = 1.27) and bilateral increase of peak hip abduction moment (prosthetic: 45 ± 40%∆, d = 1.20; intact: 23 ± 44%∆, d = 0.74) post-osseointegration. Participants demonstrated reduced peak trunk moments on both the prosthetic (extension: -31 ± 16%∆, d = 1.51; lateral flexion: -21 ± 20%∆, d = 0.63) and intact side (extension: -7 ± 22%∆, d = 0.38; lateral flexion: -22 ± 18%∆, d = 1.12) post-osseointegration. INTERPRETATION: This case series suggests improved gait symmetry in individuals with transfemoral amputation one year following osseointegration, justifying future investigation.

Improvements in disability and function in people with lower-limb amputation one year after prosthesis osseointegration.

BACKGROUND: People with lower-limb amputation (LLA) are routinely prescribed a socket prosthesis; however, many socket prosthesis users experience severe complications with the fit of their prosthesis including residual limb wounds and pain. Osseointegration is a procedure that creates a direct connection between the bone and prosthetic limb through a bone-anchored prosthesis, eliminating the need for a socket interface. It is offered as a secondary procedure to people with LLA who experience significant complications with socket prostheses. OBJECTIVES: To evaluate change in disability and function 1 year postosseointegration compared with preosseointegration in people with LLA. STUDY DESIGN: Single group, pretest, and post-test. METHODS: Twelve participants (9 transfemoral and 3 transtibial amputations, age: 44 ± 10 years, 7 female participants, 14 ± 12 years since amputation) with unilateral LLA underwent osseointegration with press-fit implants. Disability was measured with the World Health Organization Disability Assessment Schedule 2.0, and function was measured with both Prosthetic Limb Users Mobility Survey and the Activities-Specific Balance Confidence Scale. Questionnaires were administered preosseointegration and 1 year postosseointegration. Paired t tests assessed change in outcomes between time points. RESULTS: Postosseointegration, participants demonstrated reduced disability measured with World Health Organization Disability Assessment Schedule 2.0 (%Δ = -52.6, p = 0.01), improved mobility measured with Prosthetic Limb Users Mobility Survey (%Δ = 21.8, P < 0.01), and improved balance confidence measured with the Activities-Specific Balance Confidence Scale (%Δ = 28.4, P < 0.01). CONCLUSIONS: Participants report less disability and greater function in their prosthesis postosseointegration. Osseointegration is a novel procedure for people experiencing complications with their socket prosthesis, and this study is the first to show improvements in disability postosseointegration.

Understanding decision-making in prosthetic rehabilitation by prosthetists and people with lower limb amputation: a qualitative study.

PURPOSE: Little has been published about the process of decision-making between prosthetists and people with lower limb amputation (LLA). The purpose of this study is to identify decisions and factors influencing decision-making in prosthetic rehabilitation from the perspectives of prosthetists and prosthesis users, to identify barriers and opportunities for shared decision-making (SDM). METHODS: Qualitative semi-structured individual interviews were conducted with 13 prosthetists and 14 prosthesis users from three clinics in three states of the Rocky Mountain and Southwest regions of the United States. Transcripts were analyzed using thematic analysis. RESULTS: Four main themes were identified: perceived decision points, importance of relationship, balancing competing priorities, and experience. Contrasts between perceptions of prosthetists and prosthesis users were related to prosthesis design decisions, and the purpose of communication (e.g., goals for a prosthesis vs. goals informing prosthesis design). Both prosthetists and prosthesis users described balancing priorities that contribute to prosthetic rehabilitation decisions, and the role of experience for informing realistic expectations and preferences necessary for participating in decision-making. CONCLUSION: Opportunities for improving SDM between prosthetists and prosthesis users include (1) clarifying key rehabilitation decisions, (2) identifying the purpose of initial communications, (3) support for balancing priorities, and (4) utilizing experience to achieve informed preferences.IMPLICATIONS FOR REHABILITATIONMany people with lower limb amputation experience poor physical function and psychosocial outcomes, which may be further compounded by under informed prosthesis-user expectations for function with a prosthesis.Shared decision-making offers an opportunity for improving realistic prosthesis-user expectations, reducing healthcare costs, and improving prosthesis-user satisfaction and adherence to care plans.Opportunities for improving shared decision-making between prosthetists and prosthesis-users include (1) clarifying key rehabilitation decisions, (2) identifying the purpose of initial communications, (3) support for balancing priorities, and (4) utilizing experience to achieve informed preferences.

Osseointegrated prostheses improve balance and balance confidence in individuals with unilateral transfemoral limb loss.

BACKGROUND: More than half of patients with lower-limb amputation who use socket prostheses experience at least one fall annually. These falls are primarily attributed to reduced proprioception which negatively affects balance. A promising alternative to socket prostheses are osseointegrated prostheses that involve direct fixation of the prosthetic limb to the residual limb through a bone-anchored implant, yet its effect on balance remains unknown. RESEARCH QUESTION: Do osseointegrated prostheses change static and dynamic balance, as well as patient reported measures of balance confidence, compared to a socket prosthesis? METHODS: A sample of 10 patients with unilateral transfemoral amputation scheduled to undergo prosthesis osseointegration were enrolled (6 F/4 M, BMI: 26.7 ± 2.9 kg/m2, Age: 46.1 ± 6.3 years). Motion capture data during quiet standing (eyes opened and eyes closed) and overground walking at a self-selected speed, and the Activities-Specific Balance Confidence (ABC) scale, were collected before (with socket prosthesis) and 12-months following osseointegration. Postural sway via the center of pressure (COP), variability of spatiotemporal parameters, and ABC scores were compared using a repeated measures design before and after osseointegration. RESULTS: Following prosthesis osseointegration, COP path length and 95 % confidence ellipse area were reduced during quiet standing (d = 0.75, P = 0.09; d = 0.52, P = 0.29, respectively) and the variability of step width and length were reduced during overground walking (d = 0.50, P = 0.06; d = 0.72, P = 0.06, respectively). Furthermore, patients reported significantly improved ABC scores with an osseointegrated prosthesis compared to a socket prosthesis (d = -1.36, P = 0.01). SIGNIFICANCE: Improvements in postural sway, reductions in gait variability, and greater balance confidence indicate that osseointegrated prostheses improve balance for people with unilateral transfemoral amputation.

Biomechanical compensations during a stand-to-sit maneuver using transfemoral osseointegrated prostheses: A case series.

BACKGROUND: Patients with transfemoral amputation and socket prostheses are at a heightened risk of developing musculoskeletal overuse injuries, commonly due to altered joint biomechanics. Osseointegrated prostheses, which involve direct anchorage of the prosthesis to the residual limb through a bone anchored prosthesis, are a novel alternative to sockets yet their biomechanical effect is largely unknown. METHODS: Four patients scheduled to undergo unilateral transfemoral prosthesis osseointegration completed two data collections (baseline with socket prosthesis and 12-months after prosthesis osseointegration) in which whole-body kinematics and ground reaction forces were collected during stand-to-sit tasks. Trunk, pelvis, and hip kinematics, and the surrounding muscle forces, were calculated using subject-specific musculoskeletal models developed in OpenSim. Peak joint angles and muscle forces were compared between timepoints using Cohen's d effect sizes. FINDINGS: Compared to baseline with socket prostheses, patients with osseointegrated prostheses demonstrated reduced lateral trunk bending (d = 1.46), pelvic obliquity (d = 1.09), and rotation (d = 1.77) toward the amputated limb during the stand to sit task. This was accompanied by increased amputated limb hip flexor, abductor, and rotator muscle forces (d> > 0.8). INTERPRETATION: Improved lumbopelvic movement patterns and stabilizing muscle forces when using an osseointegrated prosthesis indicate that this novel prosthesis type likely reduces the risk of the development and/or progression of overuse injuries, such as low back pain and osteoarthritis. We attribute the increased muscle hip muscle forces to the increased load transmission between the osseointegrated prosthesis and residual limb, which allows a greater eccentric ability of the amputated limb to control lowering during the stand-to-sit task.

Management of Segmental Tibial Bone Defects With a Motorized Intramedullary Bone Transport Nail: A Case Review With Follow-Up.

SUMMARY: Large segment bone defects of the tibia are challenging problems. Although caused by a wide range of conditions, tibial critical bone loss defects often require complex reconstructive plans with prolonged inability to weight-bear on the effected extremity. Reconstruction options frequently require harvesting of autograft leading to further morbidity. Distraction osteogenesis allows reconstruction of large segmental defects of the tibia while avoiding donor site morbidity. Historically, distraction osteogenesis of tibia was most reliably performed with circler ring external fixation. This process allowed early weight-bearing but unfortunately has considerable drawbacks. Negative effects include pin tract irritation and inability to wear normal clothes. The advent of the bone transport nail now allows management of tibial critical bone loss defects through distraction osteogenesis negating the need for external fixation. This new technique allows treatment of large segmental tibial defects by means of distraction osteogenesis with an all-internal device avoiding the negative effects of external fixation while simultaneously allowing early weight-bearing.

Mineral bone disease in autosomal dominant polycystic kidney disease.

Mice with disruption of Pkd1 in osteoblasts demonstrate reduced bone mineral density, trabecular bone volume and cortical thickness. To date, the bone phenotype in adult patients with autosomal dominant polycystic kidney disease (ADPKD) with stage I and II chronic kidney disease has not been investigated. To examine this, we characterized biochemical markers of mineral metabolism, examined bone turnover and biology, and estimated risk of fracture in patients with ADPKD. Markers of mineral metabolism were measured in 944 patients with ADPKD and other causes of kidney disease. Histomorphometry and immunohistochemistry were compared on bone biopsies from 20 patients with ADPKD with a mean eGFR of 97 ml/min/1.73m2 and 17 healthy individuals. Furthermore, adults with end stage kidney disease (ESKD) initiating hemodialysis between 2002-2013 and estimated the risk of bone fracture associated with ADPKD as compared to other etiologies of kidney disease were examined. Intact fibroblast growth factor 23 was higher and total alkaline phosphatase lower in patients with compared to patients without ADPKD with chronic kidney disease. Compared to healthy individuals, patients with ADPKD demonstrated significantly lower osteoid volume/bone volume (0.61 vs. 1.21%) and bone formation rate/bone surface (0.012 vs. 0.026 µm3/µm2/day). ESKD due to ADPKD was not associated with a higher risk of fracture as compared to ESKD due to diabetes (age adjusted incidence rate ratio: 0.53 (95% confidence interval 0.31, 0.74) or compared to other etiologies of kidney disease. Thus, individuals with ADPKD have lower alkaline phosphatase, higher circulating intact fibroblast growth factor 23 and decreased bone formation rate. However, ADPKD is not associated with higher rates of bone fracture in ESKD.

Plantar Flexion-Induced Entrapment of the Dorsalis Pedis Artery in a Teenaged Cross-Country Runner.

BACKGROUND: Symptomatic peripheral artery disease of the lower extremity rarely affects young adults and, when present, typically has a nonatherosclerotic etiology. Anatomical variants have manifested as symptomatic foot ischemia in four cases in the literature. We describe the case of a 17-year-old girl presenting with foot pain upon plantar flexion due to dynamic dorsalis pedis (DP) artery entrapment by fibrous bands and the extensor hallucis brevis (EHB) tendon. METHODS: The patient was a 17-year-old girl who presented with right foot pain upon plantar flexion, which resolved upon returning to the neutral position. The potential site of compression was identified on MRI where the DP artery ran deep to the EHB tendon near the first and second tarsometatarsal joints. On diagnostic arteriogram, there was notching of the dorsalis pedis over the talus bone. The dorsalis pedis Doppler signal was obliterated upon plantar flexion. A longitudinal incision was made over the artery in the area of compression. The flexor retinaculum was incised. Abnormal fibrous bands were identified, which were lysed anterior to the artery. The EHB tendon was released and transferred distally to the extensor hallucis longus tendon. RESULTS: A completion angiogram showed a persistently patent dorsalis pedis artery with plantar flexion. She was discharged one day postoperatively without issues. On follow-up, the patient was ambulatory with complete resolution of her pain. Arterial duplex demonstrated normal velocities through the dorsalis pedis in all positions. CONCLUSIONS: Symptomatic peripheral artery disease is a rare presentation in young adults and is usually due to nonatherosclerotic pathophysiology. We present a rare case of dorsalis pedis artery entrapment syndrome. Given the mechanical nature of obstruction, surgical correction was an effective treatment.

Defining the volume of consultations for musculoskeletal infection encountered by pediatric orthopaedic services in the United States.

OBJECTIVE: Adequate resources are required to rapidly diagnose and treat pediatric musculoskeletal infection (MSKI). The workload MSKI consults contribute to pediatric orthopaedic services is unknown as prior epidemiologic studies are variable and negative work-ups are not included in national discharge databases. The hypothesis was tested that MSKI consults constitute a substantial volume of total consultations for pediatric orthopaedic services across the United States. STUDY DESIGN: Eighteen institutions from the Children's ORthopaedic Trauma and Infection Consortium for Evidence-based Study (CORTICES) group retrospectively reviewed a minimum of 1 year of hospital data, reporting the total number of surgeons, total consultations, and MSKI-related consultations. Consultations were classified by the location of consultation (emergency department or inpatient). Culture positivity rate and pathogens were also reported. RESULTS: 87,449 total orthopaedic consultations and 7,814 MSKI-related consultations performed by 229 pediatric orthopaedic surgeons were reviewed. There was an average of 13 orthopaedic surgeons per site each performing an average of 154 consultations per year. On average, 9% of consultations were MSKI related and 37% of these consults yielded positive cultures. Finally, a weak inverse monotonic relationship was noted between percent culture positivity and percent of total orthopedic consults for MSKI. CONCLUSION: At large, academic pediatric tertiary care centers, pediatric orthopaedic services consult on an average of ~3,000 'rule-out' MSKI cases annually. These patients account for nearly 1 in 10 orthopaedic consultations, of which 1 in 3 are culture positive. Considering that 2 in 3 consultations were culture negative, estimating resources required for pediatric orthopaedic consult services to work up and treat children based on culture positive administrative discharge data underestimates clinical need. Finally, ascertainment bias must be considered when comparing differences in culture rates from different institution's pediatric orthopaedics services, given the variability in when orthopaedic physicians become involved in a MSKI workup.

Successful Open Reduction and Internal Fixation of Proximal Humerus Fracture After Dysvascular Subcoracoid Humeral Head Dislocation: A Case Report.

CASE: We present the case of a 36-year-old patient with a 4-part proximal humerus fracture with subcoracoid dislocation and devascularization of the humeral head after a fall onto his right shoulder. CONCLUSION: The patient was successfully treated with open reduction and locking plate fixation to demonstrate that a successful postoperative functional outcome with humeral head survival can be achieved in these complex situations.