Distal Tibial Allograft for the Treatment of Anterior Shoulder Instability With Glenoid Bone Loss: A Systematic Review and Meta-analysis.

BACKGROUND: The use of a distal tibial allograft (DTA) for reconstruction of a glenoid defect in anterior shoulder instability has grown significantly over the past decade. However, few large-scale clinical studies have investigated the clinical and radiographic outcomes of the DTA procedure. PURPOSE: To conduct a systematic review and meta-analysis of clinical studies with data on outcomes and complications in patients who underwent the DTA procedure for recurrent anterior shoulder instability with glenoid bone loss. STUDY DESIGN: Systematic review and meta-analysis; Level of evidence, 4. METHODS: A comprehensive search of major bibliographic databases was conducted for articles pertaining to the use of a DTA for the management of anterior shoulder instability with associated glenoid bone loss. Postoperative complications and outcomes were extracted and compiled in a meta-analysis. RESULTS: Of the 8 included studies with 329 total participants, the mean patient age was 28.1 ± 10.8 years, 192 (83.8%) patients were male, and the mean follow-up was 38.4 ± 20.5 months. The overall complication rate was 7.1%, with hardware complications (3.8%) being the most common. Partial graft resorption was observed in 36.5% of the participants. Recurrent subluxation was reported in 1.2% of the participants, and recurrent dislocation prompting a reoperation was noted in 0.3% of the participants. There were significant improvements in clinical outcomes, including American Shoulder and Elbow Surgeons score (40.9-point increase; P < .01), Single Assessment Numeric Evaluation (47.2-point increase; P < .01), Western Ontario Shoulder Instability Index (49.4-point decrease; P < .01), Disabilities of the Arm, Shoulder and Hand (20.0-point decrease; P = .03), and visual analog scale (2.1-point decrease; P = .05). Additionally, postoperative shoulder range of motion significantly increased from baseline values. CONCLUSION: The DTA procedure was associated with a low complication rate, good clinical outcomes, and improved range of motion among patients with anterior shoulder instability and associated glenoid defects.

Rotator Cuff Tears to Shoulder Instability: The Relationship Between Acromial Morphology and Shoulder Pathology.

¼ The acromion is a well-studied region of the scapula that has demonstrated substantial relationships to various shoulder pathologies.¼ Abnormal acromial morphology is associated with rotator cuff pathology, and our understanding of this risk factor inspired acromioplasty as an adjunctive treatment for rotator cuff tears.¼ The acromion is linked closely to shoulder kinematics and biomechanics, as it serves as the origin for the deltoid muscle.¼ In degenerative shoulder disease, eccentric glenohumeral osteoarthritis has been associated with a higher, flatter acromial roof.¼ Increasing literature is emerging connecting morphology of the acromion with shoulder instability.

Percutaneous transphyseal screw induces varus proximal femoral growth modulation in a growing pig model-A three-dimensional analysis.

Bone and joint angular deformities are common pediatric orthopedic problems that are often corrected surgically. Previous studies successfully demonstrated proximal femoral growth modulation in animal models, however outcome measurements were limited by two-dimensional analysis. In this study, six Yorkshire cross male piglets were treated with unilateral percutaneous transphyseal screw placement across the medial aspect of the proximal femoral physis and analyzed using three-dimensional (3D) techniques. Three primary outcome measures were considered-physis angle, version, and femoral length. Compared to paired controls, all treated femurs displayed varus correction and shortening after an average treatment period of 10 weeks. The amount of varus change was 11.6 ± 2.8° (mean ± SD) (p = 0.0002, 95% confidence interval [CI] [8.659, 14.589]) and shortening was 4.3 ± 1.6 mm (p = 0.0011, 95% CI [2.672, 5.942]). Four animals demonstrated retroversion and two demonstrated anteversion compared to controls (4.1 ± 5.4° retroversion, p = 0.1169, 95% CI [-1.483, 9.765]). The amount of varus correction was strongly correlated with the orientation of the screw relative to the medial/lateral axis of the physis (r = -0.887, p = 0.0183, 95% CI [-0.988, -0.271]). The amount and direction of version was strongly correlated with how eccentrically anterior or posterior the screw was placed relative to the center of the physis (r = -0.850, p = 0.0322, 95% CI [-0.983, -0.123]) as well as the angle of the screw relative to the posterior condylar axis of the femur (r = -0.980, p = 0.0006, 95% CI [-0.998, -0.822]). This study is the first to use 3D analysis to quantify proximal femur growth modulation and identify associations between the growth modulation outcomes and screw placement parameters.

The Effect of Surgical Approach on the Outcomes of Same-Day Discharge Outpatient Total Hip Arthroplasty at a Single Ambulatory Surgery Center.

BACKGROUND: Primary total hip arthroplasty (THA) is increasingly being performed in the outpatient setting. However, there is little known regarding the differences in same-day discharge (SDD) rates and complications of operative approach in same-day total hip arthroplasty in the ambulatory surgery center (ASC) setting. METHODS: A retrospective chart review was performed between July 2019 and October 2021 for all patients who underwent primary THA in a single freestanding ASC. Successful SDDs, surgical approaches, lengths of surgery, estimated blood losses (EBL), complications, and readmission events were recorded for each patient. Complications were compared using Pearson Chi-Squares, while EBL and surgery lengths were compared with 1-way analysis of variances (ANOVA) (alpha = 0.5). There were 17 total complications in 326 total hip arthroplasties (5.2%), including direct admissions to the emergency department, 30-day and 90-day readmissions, wound complications, instability, infection, and revision surgery. Among all complications, there were 5 direct admissions, making the successful SDD rate 98.5%. RESULTS: Complications and direct admissions were not associated with approach. The 30-day readmission rates were associated with approach, with no readmissions in the direct anterior approach (DAA) or the antero-lateral approach (AL) cohorts and 3 (4.3%) in the posterior approach (PA) cohort. CONCLUSIONS: In the ASC setting, patients undergoing THA regardless of approach showed no difference in successful SDDs or complications aside from 30-day readmissions. Same-day THA can be safely performed in the DAA, AL, and PA to the hip.

Resilience in Residency and Beyond.

¼ Distinct from the burnout and wellness continuum, resilience is a developed and refined characteristic that propels an individual toward personal and professional success.¼ We propose a clinical resilience triangle consisting of 3 components that define resilience: grit, competence, and hope.¼ Resilience is a dynamic trait that should be built during residency and constantly fortified in independent practice so that orthopaedic surgeons may acquire and hone the skills and mental fortitude required to take on the overwhelming challenges that we all inevitably face.

Three-Column Osteotomy for Frail Versus Nonfrail Patients with Adult Spinal Deformity: Assessment of Medical and Surgical Complications, Revision Surgery Rates, and Cost.

BACKGROUND: Three-column osteotomy (3-CO) is a powerful tool for spinal deformity correction but has been associated with substantial risk and surgical invasiveness. It is incompletely understood how frailty might affect patients undergoing 3-CO. METHODS: The PearlDiver database was used to examine spinal deformity patients with a diagnosis of frailty who had undergone 3-CO. Frail and nonfrail patients were matched, and the revision surgery rates, complications, and hospitalization costs were calculated. Logistic regression was used to account for possible confounding variables. Of the 2871 included patients, 1460 had had frailty and 1411 had had no frailty. RESULTS: The frail patients were older, had had more comorbidities (P < 0.001), and were more likely to have undergone posterior interbody fusion (P < 0.05), without differences in the anterior interbody fusion rates. No differences were found in the reoperation rates for ≤5 years. At 30 days, the frail patients were more likely to have experienced acute kidney injury (P = 0.018), bowel/bladder dysfunction (P = 0.014), cardiac complications (P = 0.006), and pneumonia (P = 0.039). At 2 years, the frail patients were also more likely to have experienced bowel/bladder dysfunction (P = 0.028), cardiac complications (P < 0.001), deep vein thrombosis (P = 0.027), and sepsis (P = 0.033). The cost for the procedures was also higher for the frail patients than for the nonfrail patients ($24,544.79 vs. $21,565.63; P = 0.043). CONCLUSIONS: We found that frail patients undergoing 3-CO were more likely to experience certain medical complications and had had higher associated costs but similar reoperation rates compared with nonfrail patients. Careful patient selection and surgical strategy modification might alter the risks of medical and surgical complications after 3-CO for frail patients.

Management of patients with cervical myelopathy and normal pressure hydrocephalus: Epidemiology, medical and surgical complications.

OBJECTIVE: Normal pressure hydrocephalus (NPH) and degenerative cervical myelopathy (DCM) can each lead to gait dysfunction and urinary incontinence and may occur concurrently in some patients. In patients presenting with NPH and DCM, there is a paucity of literature describing the medical and surgical complications of treatment and the potential consequences of the sequence of surgical procedures. The aim of this study is to evaluate patients with DCM, NPH, and dual pathology to determine epidemiology and how the order of surgical intervention for both conditions may impact complications and patient outcomes. METHODS: The PearlDiver Mariner database was queried between 2010 and 2020 to identify patients by their diagnosis of NPH, DCM, or both. Additional groups were created to identify cohorts of patients who underwent ventriculoperitoneal (VP) shunting, DCM surgery, or both surgeries, as determined by the CPT, ICD9, and ICD10 codes included in the dataset. Overall demographics were reported for these cohorts of patients including age, gender, and region. Multivariable logistic regression, controlling for age, sex, and Charlson Comorbidity Index, was used to calculate odds ratios for the rates of perioperative complications within 1 year of initial ventriculoperitoneal (VP) shunt and/or DCM surgery. RESULTS: A total of 825,989 patients were identified with DCM and/or NPH: 725,433 (87.8%) had myelopathy alone, 96, 411 (11.7%), had NPH alone, and 4145 patients (0.5%) had both NPH and DCM. Of all patients with NPH, 4.8% underwent DCM surgery. Of all patients with DCM, 0.08% underwent VP shunting. Compared to NPH only patients who underwent VP shunting, patients with both pathologies undergoing VP shunting had higher odds of revision at 1-year (OR: 1.33, p-value: 0.04) and 5-years (OR: 1.36, p-value: 0.011), as well as spinal cord injury (OR: 7.77, p-value 0.016), dysphonia (OR: 2.88, p-value: 0.004), cervicalgia (OR: 2.95, p-value: 0.004), cervical kyphosis (OR: 17.49, p-value: 0.004), and limb paralysis (OR: 2.02, p-value: 0.002). Compared to DCM only patients who underwent DCM surgery, patients with both pathologies undergoing DCM surgery had higher odds of cardiac complications (OR: 1.12, p-value: 0.002), dural tear (OR: 1.66, p-value: 0.029), and dysphagia (OR: 1.28, p-value: <0.001). Patients who underwent VP shunting prior to DCM surgery had higher odds of revision shunting surgery at 1-year (OR:1.61, p-value:0.03) and 5- years (OR:2.16, p-value: <0.001). CONCLUSION: This is the largest study to date examining patients with dual cervical myelopathy and normal pressure hydrocephalus. Surgeons should carefully consider the order of VP shunting and DCM surgery, as complication rates differ depending on the order in which these surgeries are performed. Shunt revision is more common when VP shunting is performed prior to spinal decompression.

Decreased Case Volume for Orthopaedic Sports Medicine Fellows During the Early Stages of the Coronavirus Disease 2019 Pandemic.

Purpose: To compare the surgical case volume for orthopaedic sports medicine fellows in the most recent classes with one another and in years preceding the pandemic. Methods: The Accreditation Council for Graduate Medical Education case log reports of key procedures for orthopaedic sports medicine fellows during academic years 2018-2019, 2019-2020, and 2020-2021 were extracted. Comparisons between these years in adult, pediatric, and total case volumes were performed using a 2-sample t-test to detect significant changes in the average number of key procedures completed between consecutive years. Results: There was a significant decrease in the total number of cases completed by fellows during the 2020 academic year (P = .043) compared with 2019, immediately followed by a significant increase in case volume in 2021 (P < .001) (2019, 339 ± 123; 2020, 316.2 ± 108; 2021, 356.5 ± 117). There was a significant increase in adult case volume from 2020 to 2021 (2020, 295.7 ± 106; 2021, 332.9 ± 117; P < .001), whereas no trends were noted in pediatric case volume. Between the prepandemic year of 2019 and the first year of the pandemic, significant decreases were noted in case volume for several procedures, including multiligamentous knee injuries, knee instability and pediatric hip arthroscopy. From the first to the second years of the pandemic (2019-2020 to 2020-2021), significant increases were observed in case volume for rotator cuff, acromioclavicular instability, elbow instability, knee cartilage, and meniscal surgeries. Conclusions: Orthopaedic sports medicine fellows experienced significant decreases in volume for several key case categories between the year preceding the coronavirus disease 2019 pandemic and the first academic year during the pandemic. There were subsequent increases in cases between the first year of the pandemic and the second year, which may be associated with resuming elective surgical cases. Level of Evidence: IV, retrospective database analysis.

Comparison of Initial Stability of Oblong, Large Circular, and Multiple-Plug "Snowman" Osteochondral Autografts for Elongated Focal Cartilage Lesions: A Biomechanical Study in a Porcine Model.

BACKGROUND: Distal femoral osteochondral allograft transplantation (OAT) is an effective treatment of osteochondral lesions in the knee measuring >2 cm2 in select patients. Prior studies have demonstrated that the morphology of the plug can affect graft-host interference fit. To our knowledge, there are no data comparing the initial biomechanical stability of standard cylindrical plugs with multiple-plug and oblong-plug morphologies. HYPOTHESIS: Large cylindrical single-plug (LCSP) and oblong single-plug (OSP) grafts will have greater pull-out strength, and therefore greater initial stability, than multiple-plug (MP) grafts in a cadaveric porcine femur model. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 55 porcine distal femurs were divided into 3 groups-LCSP (n = 18), OSP (n = 19), and MP (n = 18)-according to the plug morphology used. The method of graft harvesting and implantation was based on technique guides for the respective implant systems. The sizes (length × width × depth) of the osteochondral defects created in each of the groups were approximately 20.2 × 20.2 × 9.4-mm for the LCSP group, 14.4 × 30.5 × 7.9-mm for the OSP group, and 14.8 × 14.8 × 9.9-mm for the MP group. Tensile testing was performed on each graft to determine pull-out strength. RESULTS: The pull-out strength was significantly lower in the OSP group (65.7 N) versus the LCSP (133 N; P = .0005) and the MP (117.6 N; P = .001) groups. There was no statistically significant difference in pull-out strength between the LCSP and MP groups (P = .42). There were no statistically significant differences in displacement at maximum load among any 2 of the 3 groups. CONCLUSION: These findings suggest that while initial stability may play a role in the clinical outcomes of osteochondral allograft (OCA) implantation, the biological milieu in vivo for each graft setting perhaps has a greater impact on the success of an OAT procedure. Further study is needed on the relationship between OCA biomechanics and clinical outcomes of OAT.

Anti-Interleukin-6 Therapy Decreases Hip Synovitis and Bone Resorption and Increases Bone Formation Following Ischemic Osteonecrosis of the Femoral Head.

Legg-Calvé-Perthes disease (LCPD) is a juvenile form of ischemic femoral head osteonecrosis, which produces chronic hip synovitis, permanent femoral head deformity, and premature osteoarthritis. Currently, there is no medical therapy for LCPD. Interleukin-6 (IL-6) is significantly elevated in the synovial fluid of patients with LCPD. We hypothesize that IL-6 elevation promotes chronic hip synovitis and impairs bone healing after ischemic osteonecrosis. We set out to test if anti-IL-6 therapy using tocilizumab can decrease hip synovitis and improve bone healing in the piglet model of LCPD. Fourteen piglets were surgically induced with ischemic osteonecrosis and assigned to two groups: the no treatment group (n = 7) and the tocilizumab group (15 to 20 mg/kg, biweekly intravenous injection, n = 7). All animals were euthanized 8 weeks after the induction of osteonecrosis. Hip synovium and femoral heads were assessed for hip synovitis and bone healing using histology, micro-CT, and histomorphometry. The mean hip synovitis score and the number of synovial macrophages and vessels were significantly lower in the tocilizumab group compared with the no treatment group (p < .0001, p = .01, and p < .01, respectively). Micro-CT analysis of the femoral heads showed a significantly higher bone volume in the tocilizumab group compared with the no treatment group (p = .02). The histologic assessment revealed a significantly lower number of osteoclasts per bone surface (p < .001) in the tocilizumab group compared with the no treatment group. Moreover, fluorochrome labeling showed a significantly higher percent of mineralizing bone surface (p < .01), bone formation rate per bone surface (p < .01), and mineral apposition rate (p = .04) in the tocilizumab group. Taken together, tocilizumab therapy decreased hip synovitis and osteoclastic bone resorption and increased new bone formation after ischemic osteonecrosis. This study provides preclinical evidence that tocilizumab decreases synovitis and improves bone healing in a large animal model of LCPD. © 2020 American Society for Bone and Mineral Research (ASBMR).

Soft tissue artifact causes underestimation of hip joint kinematics and kinetics in a rigid-body musculoskeletal model.

Rigid body musculoskeletal models have been applied to study kinematics, moments, muscle forces, and joint reaction forces in the hip. Most often, models are driven with segment motions calculated through optical tracking of markers adhered to the skin. One limitation of optical tracking is soft tissue artifact (STA), which occurs due to motion of the skin surface relative to the underlying skeleton. The purpose of this study was to quantify differences in musculoskeletal model outputs when tracking body segment positions with skin markers as compared to bony landmarks measured by direct imaging of bone motion with dual fluoroscopy (DF). Eleven asymptomatic participants with normally developed hip anatomy were imaged with DF during level treadmill walking at a self-selected speed. Hip joint kinematics and kinetics were generated using inverse kinematics, inverse dynamics, static optimization and joint reaction force analysis. The effect of STA was assessed by comparing the difference in estimates from simulations based on skin marker positions (SM) versus virtual markers on bony landmarks from DF. While patterns were similar, STA caused underestimation of kinematics, range of motion (ROM), moments, and reaction forces at the hip, including flexion-extension ROM, maximum internal rotation joint moment and peak joint reaction force magnitude. Still, kinetic differences were relatively small, and thus they may not be relevant nor clinically meaningful.

Interleukin-6 deletion stimulates revascularization and new bone formation following ischemic osteonecrosis in a murine model.

Legg-Calvé-Perthes disease (LCPD) is a childhood form of ischemic osteonecrosis of the femoral head which can produce a permanent femoral head deformity and early osteoarthritis. The femoral head deformity results from increased bone resorption and decreased bone formation during repair and remodeling of the necrotic femoral head. A recent study showed that a pro-inflammatory cytokine, interleukin-6 (IL-6), is significantly elevated in the synovial fluid of patients with LCPD. We hypothesized that IL-6 elevation decreases bone formation during the repair process following ischemic osteonecrosis and that IL-6 depletion will increase new bone formation. To test this hypothesis, we surgically induced ischemic osteonecrosis in the wild-type (n = 29) and IL-6 knockout (KO) mice (n = 25). The animals were assessed at 48 h, 2 weeks and 4 weeks following the induction of ischemic osteonecrosis using histologic, histomorphometric and micro-CT methods. IL-6 immunohistochemistry showed high expression of IL-6 in the osteonecrotic side of the wild-type mice at 48 h and 4 weeks following ischemic osteonecrosis, but not in the IL-6 KO mice. We also confirmed an undetectable level of IL-6 expression in the primary osteoblasts of the IL-6 KO mice compared to the readily detectable level in the wild-type mice. Furthermore, we confirmed that IL-6 deletion did not affect the extent of bone necrosis in the IL-6 KO mice compared to the wild-type mice by performing histologic and terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL) assessments at 2 weeks following the induction of ischemia. Both groups had the same extent of ischemic osteonecrosis and absence of repair at 2 weeks. At 4 weeks, the necrotic epiphyses showed a significant increase in the extent of revascularization in the IL-6 KO mice compared to the wild-type mice (p = 0.001). In addition, a significantly greater recovery of the hematopoietic bone marrow was observed in the osteonecrotic side of the IL-6 KO mice compared to the wild-type mice (p < 0.01). Vascular endothelial growth factor (VEGF) immunohistochemistry showed regionally increased staining in the areas of repair in the osteonecrosis side of IL-6 KO mice compared to the wild-type mice at 4 weeks following ischemic osteonecrosis. Micro-CT assessment of the wild-type mice at 4 weeks showed a significant decrease in the percent bone volume (p < 0.01) in the osteonecrotic side compared to the control side. In contrast, IL-6 KO mice showed significantly increased bone volume in the osteonecrotic side compared to the osteonecrotic side of WT mice (p < 0.001). No significant difference in the bone volume percentage was found between the control side of the wild-type and the IL-6 KO mice. Histomorphometric analysis at 4 weeks revealed increased osteoblast number/bone surface (p < 0.001), bone formation rate (BFR) (p = 0.0001), and mineral apposition rate (MAR) (p < 0.0001) in the osteonecrotic side of the IL-6 KO mice compared to the wild-type mice. The number of osteoclast/bone surface was also increased in the IL-6 KO mice compared to the wild-type mice (p < 0.0001). No significant difference was observed between the control side of the wild-type and IL-6 KO mice with regards to the number of osteoblast or osteoclast/bone surface, BFR, and MAR. We next obtained primary osteoblasts from IL-6 KO mice and showed they expressed a significantly higher level of RANKL/OPG than wild-type mice (p = 0.001) in hypoxia culture condition. Taken together, the findings indicate that IL-6 deletion stimulates revascularization and new bone formation following ischemic osteonecrosis. This study provides new evidence that therapeutic strategies to block IL-6 may be beneficial for bone healing following ischemic osteonecrosis.

Soft tissue artifact causes significant errors in the calculation of joint angles and range of motion at the hip.

Soft tissue movement between reflective skin markers and underlying bone induces errors in gait analysis. These errors are known as soft tissue artifact (STA). Prior studies have not examined how STA affects hip joint angles and range of motion (ROM) during dynamic activities. Herein, we: 1) measured STA of skin markers on the pelvis and thigh during walking, hip abduction and hip rotation, 2) quantified errors in tracking the thigh, pelvis and hip joint angles/ROM, and 3) determined whether model constraints on hip joint degrees of freedom mitigated errors. Eleven asymptomatic young adults were imaged simultaneously with retroreflective skin markers (SM) and dual fluoroscopy (DF), an X-ray technique with sub-millimeter and sub-degree accuracy. STA, defined as the range of SM positions in the DF-measured bone anatomical frame, varied based on marker location, activity and subject. Considering all skin markers and activities, mean STA ranged from 0.3cm to 5.4cm. STA caused the hip joint angle tracked with SM to be 1.9° more extended, 0.6° more adducted, and 5.8° more internally rotated than the hip tracked with DF. ROM was reduced for SM measurements relative to DF, with the largest difference of 21.8° about the internal-external axis during hip rotation. Constraining the model did not consistently reduce angle errors. Our results indicate STA causes substantial errors, particularly for markers tracking the femur and during hip internal-external rotation. This study establishes the need for future research to develop methods minimizing STA of markers on the thigh and pelvis.

In-vivo quantification of dynamic hip joint center errors and soft tissue artifact.

Hip joint center (HJC) measurement error can adversely affect predictions from biomechanical models. Soft tissue artifact (STA) may exacerbate HJC errors during dynamic motions. We quantified HJC error and the effect of STA in 11 young, asymptomatic adults during six activities. Subjects were imaged simultaneously with reflective skin markers (SM) and dual fluoroscopy (DF), an x-ray based technique with submillimeter accuracy that does not suffer from STA. Five HJCs were defined from locations of SM using three predictive (i.e., based on regression) and two functional methods; these calculations were repeated using the DF solutions. Hip joint center motion was analyzed during six degrees-of-freedom (default) and three degrees-of-freedom hip joint kinematics. The position of the DF-measured femoral head center (FHC), served as the reference to calculate HJC error. The effect of STA was quantified with mean absolute deviation. HJC errors were (mean±SD) 16.6±8.4mm and 11.7±11.0mm using SM and DF solutions, respectively. HJC errors from SM measurements were all significantly different from the FHC in at least one anatomical direction during multiple activities. The mean absolute deviation of SM-based HJCs was 2.8±0.7mm, which was greater than that for the FHC (0.6±0.1mm), suggesting that STA caused approximately 2.2mm of spurious HJC motion. Constraining the hip joint to three degrees-of-freedom led to approximately 3.1mm of spurious HJC motion. Our results indicate that STA-induced motion of the HJC contributes to the overall error, but inaccuracies inherent with predictive and functional methods appear to be a larger source of error.

Accuracy of Functional and Predictive Methods to Calculate the Hip Joint Center in Young Non-pathologic Asymptomatic Adults with Dual Fluoroscopy as a Reference Standard.

Predictions from biomechanical models of gait may be sensitive to joint center locations. Most often, the hip joint center (HJC) is derived from locations of reflective markers adhered to the skin. Here, predictive techniques use regression equations of pelvic anatomy to estimate the HJC, whereas functional methods track motion of markers placed at the pelvis and femur during a coordinated motion. Skin motion artifact may introduce errors in the estimate of HJC for both techniques. Quantifying the accuracy of these methods is an area of open investigation. In this study, we used dual fluoroscopy (DF) (a dynamic X-ray imaging technique) and three-dimensional reconstructions from computed tomography images, to measure HJC locations in vivo. Using dual fluoroscopy as the reference standard, we then assessed the accuracy of three predictive and two functional methods. Eleven non-pathologic subjects were imaged with DF and reflective skin marker motion capture. Additionally, DF-based solutions generated virtual markers placed on bony landmarks, which were input to the predictive and functional methods to determine if estimates of the HJC improved. Using skin markers, functional methods had better mean agreement with the HJC measured by DF (11.0 ± 3.3 mm) than predictive methods (18.1 ± 9.5 mm); estimates from functional and predictive methods improved when using the DF-based solutions (1.3 ± 0.9 and 17.5 ± 8.6 mm, respectively). The Harrington method was the best predictive technique using both skin markers (13.2 ± 6.5 mm) and DF-based solutions (10.6 ± 2.5 mm). The two functional methods had similar accuracy using skin makers (11.1 ± 3.6 and 10.8 ± 3.2 mm) and DF-based solutions (1.2 ± 0.8 and 1.4 ± 1.0 mm). Overall, functional methods were superior to predictive methods for HJC estimation. However, the improvements observed when using the DF-based solutions suggest that skin motion artifact is a large source of error for the functional methods.