Abstract Background Modular dual taper femoral neck designs have been associated with taper corrosion requiring revision surgery. However, outcomes after revision dual taper total hip arthroplasty in ...patients with symptomatic adverse local tissue reaction due to taper corrosion remain largely unknown. Methods A total of 198 revision surgeries in 187 patients with dual taper femoral stem total hip arthroplasty with minimum 12-month follow-up were evaluated. Results At mean follow-up of 18 months, at least 1 complication had occurred in 39 patients (20%) of 198 revisions. Single episode of dislocation, treated with close reduction, occurred in 16, whereas 2 patients required rerevision due to multiple dislocations. Infection requiring rerevision occurred in 3 patients. Adverse local tissue reaction recurrence requiring reoperation occurred in 6 patients. Implant survivorship for revision for any cause was 86% at 30 months. The reoperation rate of revised dual taper was 8% (16 out of 198 hips). The median serum levels of cobalt, chromium, and cobalt/chromium ratio decreased ( P < .01) from 5.3 μg/L (range: 2.3-48.5 μg/L), 2.6 μg/L (range: 0.2-64 μg/L), and 4.7 (range: 2.1-35) prerevision to 1.4 μg/L (range: 0.2-8.8 μg/L), 0.7 μg/L (range: 0.1-3.9 μg/L), and 2.2 (range: 0.4-8.8) postrevision, respectively. Conclusion This pilot study demonstrates that intraoperative tissue necrosis was associated with a high rate of early complications (20%) and revisions (8%), suggesting the importance of a systematic evaluation of these patients including metal ion levels and metal artifact reduction sequence magnetic resonance imaging in optimizing revision outcome, as early diagnosis will facilitate the initiation of appropriate treatment before significant adverse tissue necrosis.
Abstract Background Metal Artifact Reduction Sequence Magnetic Resonance Imaging (MARS-MRI) is an important cross-sectional imaging modality in detection of metal-on-metal (MoM) hip arthroplasty (HA) ...pseudotumours. Potential evolution of pseudotumours detected by MARS-MRI in “asymptomatic” patients with MoMHA arthroplasty beyond 2 years remains largely unknown. The aims of this longitudinal study were to (1) determine the natural history of pseudotumours in “asymptomatic” MoMHA patients under MARS-MRI surveillance and (2) characterize MRI feature(s) associated with progressive pseudotumours. Methods A total of 37 MoMHA (32 patients, mean 56 years old) with pseudotumours on MARS-MRI were evaluated longitudinally using a standardized MARS-MRI protocol. Serum cobalt and chromium levels, pseudotumour size, thickness of the cyst wall, and MRI signal intensity of the abnormality were recorded and analyzed. Results At minimum of 4-year follow-up (range 49-54 months), 4 Type II pseudotumours (11%) demonstrated MRI evidence of progression. Five Type I pseudotumours (14%) were found to have “regressed.” No measurable MRI progression was detected in remaining patients (75%). MRI features associated with progressive pseudotumours included the presence of increased cystic wall thickness and “atypical” mixed fluid signal. MRI pseudotumour progression was not associated with metal ion levels. Conclusion The natural history of type I cystic pseudotumours continues to be nonprogressive in most “asymptomatic” MoMHA patients at minimum 4 years, suggesting the importance of patient symptoms and MRI characteristic features in the clinical decision-making process. Routine follow-up MARS-MRI evaluation of “asymptomatic” patients with low-grade cystic pseudotumours in the absence of interval clinical changes may not be indicated.
Abstract This study investigated the relationships between the preoperative femoral anteversions and the femoral stem anteversion using CT scans and CT-based 3D models to determine whether any ...preoperative anteversion measurement correlates with the postoperative stem anteversion. Pre-operative and post-operative CT scans of 19 hips with THAs were evaluated. Five preoperative anatomical femoral anteversion measurements (CT-Head, CT-Below Head, CT-Neck, 3D-Head, and 3D-Neck) were compared with the postoperative femoral stem anteversion. The preoperative CT-Neck anteversion measurement was most correlated with the postoperative stem anteversion (r = 0.761, P = 0.002) with the narrowest ranges of the differences (− 10.2° to 11.0°). The preoperative anteversions using the femoral neck geometry from CT scans can be used for the estimation of the postoperative femoral stem anteversion in THA.
Background The goals of this study were to evaluate the reliability of a quantitative 3-dimensional computed tomography (Q3DCT) technique for measurement of the capitellar osteochondritis dissecans ...(OCD) surface area, to analyze OCD distribution using a mapping technique, and to investigate associations between Q3DCT lesion quantification and demographic characteristics and/or clinical examination findings. Methods We identified patients with capitellar OCD who presented to our orthopedic sports medicine practice between January 2001 and January 2016 and who had undergone a preoperative computed tomography scan (slice thickness ≤1.25 mm). A total of 17 patients with a median age of 15 years (range, 12-23 years) were included in this study. Three-dimensional polygon models were reconstructed after osseous structures were marked in 3 planes. Surface areas of the OCD lesion as well as the capitellum were measured. Observer agreement was assessed with the intraclass correlation coefficient (ICC). Heat maps were created to visualize OCD distribution. Results Measurements of the OCD surface area showed almost perfect intraobserver agreement (ICC, 0.99; confidence interval CI, 0.98-0.99) and interobserver agreement (ICC, 0.93; CI, 0.86-0.97). Measurements of the capitellar surface area also showed almost perfect intraobserver agreement (ICC, 0.97;CI, 0.91-0.99) and interobserver agreement (ICC, 0.86; CI, 0.46-0.96). The median OCD surface area was 101 mm2 (range, 49-217 mm2 ). On the basis of OCD heat mapping, the posterolateral zone of the capitellum was most frequently affected. OCDs in which the lateral wall was involved were associated with larger lesion size ( P = .041), longer duration of symptoms ( P = .030), and worse elbow extension ( P = .013). Conclusions The ability to quantify the capitellar OCD surface area and lesion location in a reliable manner using Q3DCT and a mapping technique should be considered when detailed knowledge of lesion size and location is desired.
Abstract Background An accurate diagnosis of periprosthetic joint infection (PJI) is critical as treatment of the infected total hip arthroplasty differs from aseptic failure. The clinical ...presentation of PJI may mimic symptoms of taper corrosion. Our aim was to evaluate the utility of serum inflammatory markers and synovial fluid white blood cell (WBC)/differential counts in diagnosis of PJI in failed dual taper total hip arthroplasty due to taper corrosion. Methods We retrospectively reviewed 62 dual taper modular stem patients who underwent revision surgery for symptomatic adverse local tissue reaction due to taper corrosion. All patients had preoperative hip synovial aspirations, serum inflammatory markers, metal ion levels, and intraoperative cultures. Using Musculoskeletal Infection Society PJI criteria, we divided the cohort into infected and noninfected groups. Receiver-operating characteristic curves were constructed to determine the relationship and optimal cutoff values for erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and synovial fluid counts. Results Infection group had significantly higher mean ESR ( P = .002), CRP ( P = .01), synovial fluid WBC ( P < .001), and neutrophil percentage ( P = .02). Cobalt levels were significantly elevated in noninfection group ( P = .02). Using receiver-operating characteristic curve analysis, the most ideal tests for diagnosis of PJI were synovial fluid WBC (area under the curve = 86%, optimal cutoff 730 WBC/uL) and neutrophil percentage (area under the curve = 83%, optimal cutoff 65%). ESR and CRP thresholds of 22 mm/h and 3 mg/L demonstrated 57% sensitivity and 95% specificity and 29% sensitivity and 93% specificity for detection of PJI, respectively. Conclusion Our study suggests that ESR and CRP are useful in excluding PJI in dual taper modular implants with corrosion, whereas both synovial WBC count and neutrophil percentage are useful markers for diagnosing infection.
Abstract Background context Previous studies have reported position-dependent changes of the lumbar intervertebral foramen (LIVF) dimensions at different static flexion-extension postures. However, ...the changes of the LIVF dimensions during dynamic body motion have not been reported. Purpose The objective of this study was to investigate the in vivo dimensions of the LIVF during a dynamic weight-lifting activity. Study design/Setting This was a retrospective study. Methods Ten asymptomatic subjects were recruited for this study. Three-dimensional (3D) vertebral models of the lumbar segments from L2 to S1 were constructed for each subject using magnetic resonance images. The lumbar spine was then imaged using a dual fluoroscopic imaging system as the subject performed a dynamic weight-lifting activity from an upper body position of 45° to a maximal extension position. The in vivo positions of the vertebrae along the motion path were reproduced using the 3D vertebral models and the fluoroscopic images. The minimal area, height, and width of each LIVF during the dynamic body motion were analyzed. Results The LIVF area and width monotonically decreased with lumbar extension at all levels except L5–S1 (p<.05). On average, the LIVF area decreased by 7.4±6.7%, 10.8±7.7%, and 10.0±8.0% at the L2–L3, L3–L4, and L4–L5 levels, respectively, from the flexion to the upright standing position, and by 6.4±5.0%, 7.7±7.4%, and 5.1±5.1%, respectively, from the upright standing to the extension position. The LIVF height remained relatively constant at all segments during the dynamic activity. The foramen area, height, and width of the L5–S1 remained relatively constant throughout the activity. Conclusions Human lumbar foramen dimensions show segment-dependent characteristics during the dynamic weight-lifting activity.
Abstract Background Current guidelines recommend longitudinal monitoring of at-risk metal-on-metal (MoM) arthroplasty patients with cross-sectional imaging such as metal artifact reduction sequence ...(MARS) magnetic resonance imaging (MRI) or ultrasound. During follow-up evaluations, the clinical focus is on the relative interval changes in symptoms, radiographs, laboratory tests, and cross-sectional imaging modalities. Although MRI has the capacity for the detection of adverse local soft tissue reactions (ALTRs), the potential disadvantages of MARS MRI include the obscuration of periprosthetic tissues by metal artifacts and the cost. The aim of this study was to evaluate the diagnostic accuracy of ultrasound in comparison with MARS MRI in detecting ALTR in MoM patients during consecutive follow-up. Methods Thirty-five MoM patients (42 hips) were recruited prospectively to evaluate the sensitivity and specificity of the ultrasound for detecting ALTR in relation to MARS MRI during 2 longitudinal follow-up scans. The agreement between ultrasound and MARS MRI in ALTR grade, size, and size change was calculated. Results At the initial evaluation and at the subsequent follow-up, ultrasound had a sensitivity of 81% and 86% and a specificity of 92% and 88%, respectively. At the follow-up evaluations, ultrasound was able to detect the “change” in the lesions size with −0.3 cm2 average bias from the MARS MRI with higher agreement (k = 0.85) with MARS MRI compared to the initial evaluation in detecting any “change” in ALTR size or grade. Conclusion Ultrasound detected the interval change in the ALTR size and grade with higher accuracy and higher agreement with MARS MRI compared with the initial evaluation, suggesting ultrasound is a valid and useful.
Abstract Background Contemporary ‘dual-taper’ modular femoral neck stem designs have been associated with taper corrosion related adverse local tissue reaction (ALTR) requiring revision surgery and ...stem removal. Extended trochanteric osteotomy (ETO) is recognized as the workhorse procedure for revision hip surgery. The aim of our study is to describe our “top out” stem removal surgical technique and identify preoperative radiographic risk factors associated with periprosthetic fractures when utilizing this technique. Methods This is a single-center, single-surgeon, retrospective case series. Operative and clinic records were reviewed for patients with ‘dual-taper’ modular femoral neck stem that underwent revision surgery for taper tribocorrosion related adverse local tissue reaction. Results 83 patients (36 males and 47 females, mean age 61.8±10.3, BMI 30.2±8.6) were revised using the “top-out” technique. Significant improvements in postoperative HHS (p=0.004), EQ-5D (p<0.001) and EQ-5D US-adjusted scores (p<0.001) were observed at 19 months follow-up. Our study reports periprosthetic fracture incidence of 14% and reoperation rate of 7%. Periprosthetic fractures were positively correlated with radiographic parameters such as overhang distance (R=0.376,p=0.002), overhang ratio (R=0.312,p=0.01) and negatively correlated with radiographic implant medial calcar prominence (R=-0.299,p=0.01). Conclusion Removal of well-fixed femoral components can be challenging and the burden of revision surgery for taper tribocorrosion related adverse local tissue reaction of these femoral stems is likely to rise. A “top out” technique provides a viable, alternative surgical option to remove well fixed femoral component while preserving the femoral bony envelope.
Abstract Background Component malalignment in unicompartmental knee arthroplasty (UKA) has been associated with contact stress concentration and poor clinical outcomes. However, there is a paucity of ...data regarding UKA component alignment and in vivo articular contact in weight-bearing position. This study aims to (1) quantify three-dimensional UKA component alignment and (2) evaluate the association between the component alignment and in vivo articular contact in standing position. Methods Seventy-seven UKAs in 68 consecutive patients were imaged in standing position using a biplanar X-ray imaging acquisition system. The UKA models were imported into a virtual imaging environment and registered with component silhouette on X-ray image for determination of component position and contact location. Anatomic bony landmarks of the lower limb were digitized for quantification of the bone alignment. Results The femoral component (FC) showed 1.6° ± 3.3° valgus, 6.5° ± 6.4° external rotation, and 2.4° ± 4.6° flexion. The tibial component (TC) showed 3.9° ± 4.5° varus, 4.4° ± 6.7° internal rotation, and 10.1° ± 4.6° tibial slope. The average contact point was located medially and posteriorly by 7.8 ± 7.6% and 0.7 ± 7.7% of TC dimensions to its center. Multiple regression analysis identified FC flexion as a significant variable affecting UKA anterior and/or posterior contact position (R = 0.549, P < .001). Conclusion This study demonstrated the highest variability of UKA component positioning in axial plane rotation for FC and TC. The association between FC flexion and anterior contact position suggests accurate implant positioning may be important in optimizing in vivo UKA contact behavior. Further studies are required to gain understanding of the influence of axial rotation variability on in vivo UKA contact kinematics during functional activities.
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