BACKGROUND: In revision total knee arthroplasty (TKA), there is little information on the magnitude of potential limb lengthening, risk factors for lengthening, or its impact on patient-reported outcome measures. We aimed to quantify limb length alteration during revision TKA and assess risk factors for lengthening. METHODS: We identified 150 patients over a 3-year period who underwent revision TKA and had preoperative and postoperative EOS hip-to-ankle standing radiographs. The average patient age was 64 years, 51% were women; 68% had a pre-operative varus deformity and 21% had a pre-operative valgus deformity. Outcomes assessed included change in functional and anatomic limb length, risk factors for lengthening, and clinical outcome scores, including the Knee Osteoarthritis Outcome Score Joint Replacement (KOOS JR), and the Veterans RAND 12-item (VR12) Physical and Mental Scores. RESULTS: There were 124 patients (83%) who had functional limb lengthening, and 108 patients (72%) had anatomic limb lengthening. Patients had an average functional limb lengthening of 7 mm (range, -22 to 35) and an average anatomic limb lengthening of 5 mm (range, -16 to 31). Patients undergoing revision for instability experienced significantly greater anatomic lengthening (7.6 versus 4.6, P = 0.047). Patients who had ≥ 10° of deformity were more likely to be functionally lengthened (91 versus 79%) and had significantly greater average functional lengthening (12 versus 6 mm; P = 0.003). There was no significant change in clinical outcome scores at 6 weeks and 1 year for patients lengthened ≥ 5 or 10 mm compared to those not lengthened as substantially. CONCLUSIONS: There is major potential for functional and anatomic limb lengthening following revision TKA, with greater preoperative deformity and revision for instability being risk factors for lengthening.
INTRODUCTION: Interprosthetic femur fractures (IPFFs) are a rare, but devastating complication following total joint arthroplasty. There is limited evidence to help guide their management. The purpose of this study was to describe the features, treatment, and outcomes of surgically managed IPFFs. METHODS: We retrospectively identified 75 patients who had 76 IPFFs. The mean age at the time of IPFF was 75 years (range, 29 to 94), and 78% were women. The mean body mass index was 30 (range, 19 to 51), and the mean follow-up was 3 years (range, 0 to 14). There were 16 Vancouver B1 fractures, 28 Vancouver B2 fractures, 2 Vancouver B3 fractures, and 30 Vancouver C fractures. All B1 fractures underwent open reduction internal fixation (ORIF). All Vancouver B2 and B3 fractures underwent revision arthroplasty, including 1 proximal femur replacement (PFR) and 1 total femur replacement (TFR). Vancouver C fractures were treated with ORIF (n = 20), distal femoral replacement (DFR) (n = 9), and in one case, TFR (n = 1). Kaplan-Meier survivorship was used to calculate 2-year survival free from all-cause reoperation and periprosthetic joint infection (PJI). RESULTS: The 2-year survivorship-free rate from reoperation was 71%. There were 18 reoperations following initial surgical management of the IPFF, including 9 for infection, 3 for re-fracture, 3 for nonunion, 2 for hardware failure, and 1 for instability. An initial IPFF involving a stemmed femoral TKA component was associated with increased risk for reoperation (P = 0.007) and PJI (P = 0.044). There was no difference in survivorship free of reoperation between IPFFs managed with ORIF or revision arthroplasty (P = 0.72). CONCLUSION: An IPFF is a devastating complication following total joint arthroplasty with high reoperation rates, most commonly secondary to PJI. Those IPFFs that occurred between two stemmed components were at the highest risk for reoperation.
Patient-specific flanged acetabular components are utilized to treat failed total hip arthroplasties with large acetabular defects. Previous clinical studies from our institution showed that these implants tend to lateralize the acetabular center of rotation. However, the clinical impact of lateralization on implant survivorship is debated. Our goal was to develop a finite element model to quantify how lateralization of the native hip center affects periprosthetic strain and implant-bone micromotion distributions in a static level gait loading condition. To build the model, we computationally created a superomedial acetabular defect in a computed tomography 3D reconstruction of a native pelvis and designed a flanged acetabular implant to address this simulated bone defect. We modeled two implants, one with ~1 cm and a second with ~2 cm of hip center lateralization. We applied the maximum hip contact force and corresponding abductor force observed during level gait. The resulting strains were compared to bone fatigue strength (0.3% strain) and the micromotions were compared to the threshold for bone ingrowth (20 µm). Overall, the model demonstrated that the additional lateralization only slightly increased the area of bone at risk of failure and decreased the areas compatible with bone ingrowth. This computational study of patient-specific acetabular implants establishes the utility of our modeling approach. Further refinement will yield a model that can explore a multitude of variables and could be used to develop a biomechanically-based acetabular bone loss classification system to guide the development of patient-specific implants in the treatment of large acetabular bone defects.
INTRODUCTION: Options for soft tissue coverage in revision total knee arthroplasty (rTKA) range from primary wound closure to complex muscle flap reconstructions. The purpose of this study was to investigate the institutional experience of wound coverage options for complex soft tissue defects in rTKA. MATERIALS AND METHODS: 77 patients undergoing rTKA with complex wound closure by a single plastic surgeon were retrospectively reviewed. The average follow-up was 30.1 months. In 18 (23.4%) patients, an intraoperative decision for primary closure was made. Fifty-nine patients (76.6%) received either a local fasciocutaneous (N = 18), a medial gastrocnemius (N = 37), a free latissimus dorsi (N = 3) or a lateral gastrocnemius flap (N = 1). Revision-free survival and complication rates were assessed and risk factors were analyzed with Cox-regression analysis. RESULTS: Medial gastrocnemius flaps had significant lower cumulative revision-free survival rates than local fasciocutaneous flaps (P = 0.021) and primary closures (P < 0.001) (42.5% vs. 71.5% vs. 100%,respectively). Comparing the most common complex closure procedures medial gastrocnemius flaps had the highest rate of prolonged wound healing (29.7%) and infection/reinfection (40.5%). Infection-associated flap procedures had significant lower cumulative revision-free survival rates (30.5%) than non-infection associated flap procedures (62.8%,P = 0.047). A history of more than two prior surgeries (HR = 6.11,P < 0.001) and an age ≥ 65 years (HR = 0.30,P = 0.018) significantly increased the risk of revision. CONCLUSIONS: The results of this study indicate that primary closure -if possible- should be preferred to early proactive muscle flap coverage. Even in the hands of an experienced plastic surgeon muscle flaps have high revision and complication rates. The study highlights the need to clarify flap indications and to investigate alternative approaches.
Robotic assisted (RA) total hip arthroplasty (THA) offers improved acetabular component placement and radiographic outcomes, but inconsistent assessment methods of its learning curves render the evaluation of adopting novel platforms challenging. Therefore, we conducted a systematic review to assess the learning curve associated with RA-THA, both tracking a surgeon's performance across initial cases and comparing their performance to manual THA (M-THA). PubMed, MEDLINE, EBSCOhost, and Google Scholar were searched on June 16, 2023, to identify studies published between January 1, 2000 and June 16, 2023 (PROSPERO registration: CRD42023437339). The query yielded 655 unique articles, which were screened for eligibility. The final analysis included 11 articles, evaluating 1351 THA procedures. Risk of bias was assessed via the Methodological Index for Nonrandomized Studies (MINORS) tool. The mean MINORS score was 21.3 ± 0.9. RA-THA provided immediate improvements in acetabular component placement accuracy and radiographic outcomes compared to M-THA, with little to no experience required to achieve peak proficiency. A modest learning curve (12-17 cases) was associated with operative time, which was elevated compared to M-THA (+ 9-13 min). RA-THA offers immediate advantages to M-THA for component placement accuracy and radiographic outcomes. Surgeons should expect to experience increased operative times, which become less pronounced or equivalent to M-THA after a modest caseload.
Arthroplasty, Replacement, Hip , Robotic Surgical Procedures , Surgery, Computer-Assisted , Humans , Arthroplasty, Replacement, Hip/methods , Learning Curve , Robotic Surgical Procedures/methods , Acetabulum/diagnostic imaging , Acetabulum/surgery , Surgery, Computer-Assisted/methods
BACKGROUND: Partial or total release of the posterior cruciate ligament (PCL) is often performed intraoperatively in cruciate-retaining total knee arthroplasty (CR-TKA) to alleviate excessive femoral rollback. However, the effect of the release of selected fibers of the PCL on femoral rollback in CR-TKA is not well understood. Therefore, we used a computational model to quantify the effect of selective PCL fiber releases on femoral rollback in CR-TKA. METHODS: Computational models of 9 cadaveric knees (age: 63 years, range 47 to 79) were virtually implanted with a CR-TKA. Passive flexion was simulated with the PCL retained and after serially releasing each individual fiber of the PCL, starting with the one located most anteriorly and laterally on the femoral notch and finishing with the one located most posteriorly on the medial femoral condyle. The experiment was repeated after releasing only the central PCL fiber. The femoral rollback of each condyle was defined as the anterior-posterior distance between tibiofemoral contact points at 0° and 90° of flexion. RESULTS: Release of the central PCL fiber in combination with the anterolateral (AL) fibers, reduced femoral rollback a median of 1.5 [0.8, 2.1] mm (P = .01) medially and by 2.0 [1.2, 2.5] mm (P = .04) laterally. Releasing the central fiber alone reduced the rollback by 0.7 [0.4, 1.1] mm (P < .01) medially and by 1.0 [0.5, 1.1] mm (P < .01) laterally, accounting for 47 and 50% of the reduction when released in combination with the AL fibers. CONCLUSIONS: Releasing the central fibers of the PCL had the largest impact on reducing femoral rollback, either alone or in combination with the release of the entire AL bundle. Thus, our findings provide clinical guidance regarding the regions of the PCL that surgeons should target to reduce femoral rollback in CR-TKA.
Aims: Obtaining solid implant fixation is crucial in revision total knee arthroplasty (rTKA) to avoid aseptic loosening, a major reason for re-revision. This study aims to validate a novel grading system that quantifies implant fixation across three anatomical zones (epiphysis, metaphysis, diaphysis). Methods: Based on pre-, intra-, and postoperative assessments, the novel grading system allocates a quantitative score (0, 0.5, or 1 point) for the quality of fixation achieved in each anatomical zone. The criteria used by the algorithm to assign the score include the bone quality, the size of the bone defect, and the type of fixation used. A consecutive cohort of 245 patients undergoing rTKA from 2012 to 2018 were evaluated using the current novel scoring system and followed prospectively. In addition, 100 first-time revision cases were assessed radiologically from the original cohort and graded by three observers to evaluate the intra- and inter-rater reliability of the novel radiological grading system. Results: At a mean follow-up of 90 months (64 to 130), only two out of 245 cases failed due to aseptic loosening. Intraoperative grading yielded mean scores of 1.87 (95% confidence interval (CI) 1.82 to 1.92) for the femur and 1.96 (95% CI 1.92 to 2.0) for the tibia. Only 3.7% of femoral and 1.7% of tibial reconstructions fell below the 1.5-point threshold, which included the two cases of aseptic loosening. Interobserver reliability for postoperative radiological grading was 0.97 for the femur and 0.85 for the tibia. Conclusion: A minimum score of 1.5 points for each skeletal segment appears to be a reasonable cut-off to define sufficient fixation in rTKA. There were no revisions for aseptic loosening at mid-term follow-up when this fixation threshold was achieved or exceeded. When assessing first-time revisions, this novel grading system has shown excellent intra- and interobserver reliability.
Arthroplasty, Replacement, Knee , Knee Prosthesis , Prosthesis Failure , Reoperation , Humans , Arthroplasty, Replacement, Knee/methods , Female , Male , Aged , Middle Aged , Aged, 80 and over , Reproducibility of Results , Prospective Studies , Femur/surgery , Tibia/surgery , Follow-Up Studies
BACKGROUND: Tapered fluted titanium (TFT) stems are the implant design of choice for managing Vancouver B2 periprosthetic femur fractures (PFFs), producing reliable results over the past few decades. The aim of this study was to compare the radiographic and clinical outcomes of Vancouver B2 PFFs treated with contemporary monoblock versus modular TFTs. METHODS: A consecutive series of 113 patients (72 women, 64%, mean age 70 years [range, 26 to 96]) who had a B2 PFF were treated with either a monoblock (n = 42) or modular (n = 71) TFT stem between 2008 and 2021. The mean body mass index was 30 ± 7. The mean follow-up was 2.9 years. A radiographic review was performed to assess leg length and offset restoration, endosteal cortical contact length, and stem subsidence. Kaplan-Meier analyses were used to determine survivorship without revision, reoperation, or dislocation. RESULTS: There was no difference in the restoration of leg length (0.3 ± 8.0 mm) or offset (2.8 ± 8.2 mm) between the monoblock and modular cohorts (P > .05). Mean endosteal cortical contact length (47.2 ± 26.6 versus 46.7 ± 2 6.4 mm, P = .89) and stem subsidence (2.7 ± 3.5 versus 2.4 ± 3.2 mm, P = .66) did not differ. No difference in patient-reported outcome measures (Hip Disability and Osteoarthritis Outcome Score-Joint Replacement; Veterans RAND 12 Item Health Survey Physical and Mental; visual analog score; and Lower Extremity Activity Scale) between the groups was observed. Survivorship at 2 years free from reoperation, revision, and dislocation was 90.4, 90.3, and 97.6%, respectively, for the monoblock cohort; and 84.0, 86.9, and 90.0%, respectively, for the modular cohort. CONCLUSIONS: No significant differences in radiographic or clinical outcomes were observed between patients treated with monoblock or modular TFTs in this large series of B2 PFFs.
BACKGROUND: Cementless total knee arthroplasty (TKA) has regained interest for its potential for long-term biologic fixation. The density of the bone is related to its ability to resist static and cyclic loading and can affect long-term implant fixation; however, little is known about the density distribution of periarticular bone in TKA patients. Thus, we sought to characterize the bone mineral density (BMD) of the proximal tibia in TKA patients. METHODS: We included 42 women and 50 men (mean age 63 years, range: 50 to 87; mean body mass index 31.6, range: 20.5 to 49.1) who underwent robotic-assisted TKA and had preoperative computed tomography scans with a BMD calibration phantom. Using the robotic surgical plan, we computed the BMD distribution at 1 mm-spaced cross-sections parallel to the tibial cut from 2 mm above the cut to 10 mm below. The BMD was analyzed with respect to patient sex, age, preoperative alignment, and type of fixation. RESULTS: The BMD decreased from proximal to distal. The greatest changes occurred within ± 2 mm of the tibial cut. Age did not affect BMD for men; however, women between 60 and 70 years had higher BMD than women ≥ 70 years for the total cut (P = .03) and the medial half of the cut (P = .03). Cemented implants were used in 1 86-year-old man and 18 women (seven < 60 years, seven 60 to 70 years, and four ≥ 70 year old). We found only BMD differences between cemented or cementless fixation for women < 60 years. CONCLUSIONS: To our knowledge, this is the first study to characterize the preoperative BMD distribution in TKA patients relative to the intraoperative tibial cut. Our results indicate that while sex and age may be useful surrogates of BMD, the clinically relevant thresholds for cementless knees remain unclear, offering an area for future studies.
PURPOSE: Computer-navigated (CN) total hip arthroplasty (THA) offers improved acetabular component placement and radiographic outcomes, but inconsistent assessment methods of its learning curves render the evaluation of adopting a novel platform challenging. Therefore, we conducted a systematic review to assess the learning curve associated with CN-THA, both tracking a surgeon's performance across initial cases and comparing their performance to manual THA (M-THA). METHODS: A search was conducted using PubMed, MEDLINE, EBSCOhost, and Google Scholar on June 16, 2023 to find research articles published after January 1, 2000 (PROSPERO registration: CRD4202339403) that investigated the learning curve associated with CN-THA. 655 distinct articles were retrieved and subsequently screened for eligibility. In the final analysis, nine publications totaling 847 THAs were evaluated. The Methodological Index for Nonrandomized Studies (MINORS) tool was utilized to evaluate the potential for bias, with the mean MINORS score of 21.3 ± 1.2. RESULTS: CN-THA showed early advantages to M-THA for component placement accuracy and radiographic outcomes but longer operative times (+ 3- 20 min). There was a learning curve required to achieve peak proficiency in these metrics, though mixed methodologies made the required caseload unclear. CONCLUSIONS: CN-THA offers immediate advantages to M-THA for component placement accuracy and radiographic outcomes, though CN-THA's advantages become more pronounced with experience. Surgeons should anticipate longer operative times during the learning curve for CN-THA, which lessen following a modest caseload. A more thorough evaluation of novel computer-navigated technologies would be enhanced by adopting a more uniform method of defining learning curves for outcomes of interest. Registration PROSPERO registration of the study protocol: CRD42023394031, 27 June 2023.
Arthroplasty, Replacement, Hip , Robotic Surgical Procedures , Humans , Arthroplasty, Replacement, Hip/methods , Learning Curve , Robotic Surgical Procedures/methods , Treatment Outcome , Computers
INTRODUCTION: There are two variants regarding the low location of the patella in relation to the tibio-femoral joint line: patella baja (PB) and pseudo-patella baja (PPB). The purpose of this study is to investigate the incidence of PB and PPB in a cohort of patients that underwent revision total knee arthroplasty (rTKA) for aseptic reasons and describe any differences in each group's ROM. METHODS: This retrospective study included 114 patients that underwent aseptic revision TKA surgery between 2017 and 2022. Patients were revised either for stiffness (Group 1) or aseptic loosening/instability (Group 2). The Insall-Salvati ratio (ISR) and Blackburne-Peel ratio (BPR) were used to evaluate the patellar position. ISR < 0.8 defined PB, while cases with ISR ≥ 0.8 and BPI < 0.54 were defined as PPB. ROM was measured and a subanalysis was conducted to investigate the progression of the values of ISR and BPR. RESULTS: 55 patients comprised Group 1, and 59 patients comprised Group 2. Overall, 13 cases (11.4%) had PB before rTKA and 24 (21%) had PB after rTKA. Cases with PPB were 13 (11.4%) before and 34 (29.9%) after rTKA. Group 1 patients presented with more PB before and after rTKA (12.8% vs 10.2% and 27.3% vs 15.2% respectively). However, after rTKA Group 1 patients presented with less PPB (20%) compared to Group 2 (39%) (p = 0.02). In Group 1, patients with PPB after rTKA had less ROM compared to those without PPB [83.2 (± 21.9) vs 102.1 (± 19.9) (p = 0.025)]. The subanalysis (69 patients) showed a statistically significant decrease in ISR before and after rTKA (p = 0.041), and from the native knee to post-rTKA (p = 0.001). There was a statistically significant decrease in BPR before and after rTKA (p = 0.001) and from the native knee to both pre- and post-rTKA (p < 001). CONCLUSION: After undergoing rTKA, the incidences of both patella baja (PB) and pseudo-patella baja (PPB) increased. Stiffness in the knee was associated with a higher incidence of PB, while non-stiffness cases showed a significantly higher incidence of PPB. Patients with stiff knees and PPB after rTKA experienced a significant reduction in range of motion (ROM). Additionally, the study revealed a noteworthy decrease in ISR and BPR with each subsequent surgery. This information is crucial for healthcare providers, as it sheds light on potential risks and outcomes of rTKA, allowing for improved patient management and surgical decision-making. LEVEL OF EVIDENCE: III.
Arthroplasty, Replacement, Knee , Joint Diseases , Knee Prosthesis , Humans , Arthroplasty, Replacement, Knee/adverse effects , Patella/surgery , Incidence , Retrospective Studies , Knee Joint/surgery , Joint Diseases/surgery , Range of Motion, Articular , Knee Prosthesis/adverse effects
BACKGROUND: Chronic extensor mechanism disruption after total knee arthroplasty (TKA) is a rare but challenging condition. There are several surgical approaches for quadriceps tendon repairs. In this report, we present a modified surgical technique for quadriceps tendon repair in chronic extensor mechanism disruption without the use of allografts or mesh augmentation. METHODS: We retrospectively reviewed 12 consecutive cases of chronic extensor mechanism with complete quadriceps tendon ruptures after TKA that underwent the advancement and imbrication technique. Patient outcomes were evaluated using the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, the range of motion and extensor lag measurements, and standardized lateral radiographs were reviewed for Insall-Salvati-Ratio preoperatively and at their most recent follow-up visit. RESULTS: There were 12 knees from patients who had a mean age of 72 years (range, 62 to 81) and were evaluated with a mean follow-up of 15.9 months (range, 11.4 to 50.9). The extensor lag significantly improved from 40.8 ± 31.9° (range, 10 to 90°) to 2.9 ± 6.9° (P = .014), the Insall-Salvati-Ratio significantly changed from 0.87 to 1.07 (P = .010), and the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement showed a significant difference: a raw score of 13.0 ± 5.8 versus 8.7 ± 5.6 (P = .002) and an interval score of 54.1 ± 14.0 versus 66.2 ± 15.6 (P = .001). CONCLUSIONS: Reconstruction of extensor mechanism in chronic quadriceps tendon ruptures after TKA with the advancement and imbrication technique showed excellent functional outcomes with no extensor lag and excellent restoration of motion. This technique can be combined with TKA revision surgery or used on its own. To ensure successful outcomes, the authors favor rigid immobilization for 12 weeks before starting mobilization.
BACKGROUND: Manipulation under anesthesia (MUA) occurs in 4% of patients after total knee arthroplasty (TKA). Anti-inflammatory medications may target arthrofibrosis pathogenesis, but the data are limited. This multicenter randomized clinical trial investigated the effect of adjuvant anti-inflammatory medications with MUA and physical therapy on range of motion (ROM) and outcomes. METHODS: There were 124 patients (124 TKAs) who developed stiffness after primary TKA for osteoarthritis enrolled across 15 institutions. All received MUA when ROM was < 90° at 4 to 12 weeks postoperatively. Randomization proceeded via a permuted block design. Controls received MUA and physical therapy, while the treatment group also received one dose of pre-MUA intravenous dexamethasone (8 mg) and 14 days of oral celecoxib (200 mg). The ROM and clinical outcomes were assessed at 6 weeks and 1 year. This trial was registered with ClinicalTrials.gov. RESULTS: The ROM significantly improved a mean of 46° from a pre-MUA ROM of 72 to 118° immediately after MUA (P < .001). The ROM was similar between the treatment and control groups at 6 weeks following MUA (101 versus 99°, respectively; P = .35) and at one year following MUA (108 versus 108°, respectively; P = .98). Clinical outcomes were similar at both end points. CONCLUSIONS: In this multicenter randomized clinical trial, the addition of intravenous dexamethasone and a short course of oral celecoxib after MUA did not improve ROM or outcomes. However, MUA provided a mean ROM improvement of 46° immediately, 28° at 6 weeks, and 37° at 1 year. Further investigation in regards to dosing, duration, and route of administration of anti-inflammatory medications remains warranted. LEVEL OF EVIDENCE: Level 1, RCT.
Aims: Periprosthetic femoral fracture (PPF) is a major complication following total hip arthroplasty (THA). Uncemented femoral components are widely preferred in primary THA, but are associated with higher PPF risk than cemented components. Collared components have reduced PPF rates following uncemented primary THA compared to collarless components, while maintaining similar prosthetic designs. The purpose of this study was to analyze PPF rate between collarless and collared component designs in a consecutive cohort of posterior approach THAs performed by two high-volume surgeons. Methods: This retrospective series included 1,888 uncemented primary THAs using the posterior approach performed by two surgeons (PKS, JMV) from January 2016 to December 2022. Both surgeons switched from collarless to collared components in mid-2020, which was the only change in surgical practice. Data related to component design, PPF rate, and requirement for revision surgery were collected. A total of 1,123 patients (59.5%) received a collarless femoral component and 765 (40.5%) received a collared component. PPFs were identified using medical records and radiological imaging. Fracture rates between collared and collarless components were analyzed. Power analysis confirmed 80% power of the sample to detect a significant difference in PPF rates, and a Fisher's exact test was performed to determine an association between collared and collarless component use on PPF rates. Results: Overall, 17 PPFs occurred (0.9%). There were 16 fractures out of 1,123 collarless femoral components (1.42%) and one fracture out of 765 collared components (0.13%; p = 0.002). The majority of fractures (n = 14; 82.4%) occurred within 90 days of primary THA. There were ten reoperations for PPF with collarless components (0.89%) and one reoperation with a collared component (0.13%; p = 0.034). Conclusion: Collared femoral components were associated with significant decreases in PPF rate and reoperation rate for PPF compared to collarless components in uncemented primary THA. Future studies should investigate whether new-generation collared components reduce PPF rates with longer-term follow-up.
Arthroplasty, Replacement, Hip , Femoral Fractures , Hip Prosthesis , Periprosthetic Fractures , Humans , Arthroplasty, Replacement, Hip/adverse effects , Periprosthetic Fractures/etiology , Periprosthetic Fractures/prevention & control , Periprosthetic Fractures/surgery , Retrospective Studies , Prosthesis Design , Femoral Fractures/etiology , Femoral Fractures/prevention & control , Femoral Fractures/surgery
Computational studies of total knee arthroplasty (TKA) often focus on either joint mechanics (kinematics and forces) or implant fixation mechanics. However, such disconnect between joint and fixation mechanics hinders our understanding of overall TKA biomechanical function by preventing identification of key relationships between these two levels of TKA mechanics. We developed a computational workflow to holistically assess TKA biomechanics by integrating musculoskeletal and finite element (FE) models. For our initial study using the workflow, we investigated how tibiofemoral contact mechanics affected the risk of failure due to debonding at the implant-cement interface using the four available subjects from the Grand Challenge Competitions to Predict In Vivo Knee Loads. We used a musculoskeletal model with a 12 degrees-of-freedom knee joint to simulate the stance phase of gait for each subject. The computed tibiofemoral joint forces at each node in contact were direct inputs to FE simulations of the same subjects. We found that the peak risk of failure did not coincide with the peak joint forces or the extreme tibiofemoral contact positions. Moreover, despite the consistency of joint forces across subjects, we observed important variability in the profile of the risk of failure during gait. Thus, by a combined evaluation of the joint and implant fixation mechanics of TKA, we could identify subject-specific effects of joint kinematics and forces on implant fixation that would otherwise have gone unnoticed. We intend to apply our workflow to evaluate the impact of implant alignment and design on TKA biomechanics.
Arthroplasty, Replacement, Knee , Knee Prosthesis , Humans , Biomechanical Phenomena , Workflow , Range of Motion, Articular , Knee Joint/surgery
Aims: Distal femoral resection in conventional total knee arthroplasty (TKA) utilizes an intramedullary guide to determine coronal alignment, commonly planned for 5° of valgus. However, a standard 5° resection angle may contribute to malalignment in patients with variability in the femoral anatomical and mechanical axis angle. The purpose of the study was to leverage deep learning (DL) to measure the femoral mechanical-anatomical axis angle (FMAA) in a heterogeneous cohort. Methods: Patients with full-limb radiographs from the Osteoarthritis Initiative were included. A DL workflow was created to measure the FMAA and validated against human measurements. To reflect potential intramedullary guide placement during manual TKA, two different FMAAs were calculated either using a line approximating the entire diaphyseal shaft, and a line connecting the apex of the femoral intercondylar sulcus to the centre of the diaphysis. The proportion of FMAAs outside a range of 5.0° (SD 2.0°) was calculated for both definitions, and FMAA was compared using univariate analyses across sex, BMI, knee alignment, and femur length. Results: The algorithm measured 1,078 radiographs at a rate of 12.6 s/image (2,156 unique measurements in 3.8 hours). There was no significant difference or bias between reader and algorithm measurements for the FMAA (p = 0.130 to 0.563). The FMAA was 6.3° (SD 1.0°; 25% outside range of 5.0° (SD 2.0°)) using definition one and 4.6° (SD 1.3°; 13% outside range of 5.0° (SD 2.0°)) using definition two. Differences between males and females were observed using definition two (males more valgus; p < 0.001). Conclusion: We developed a rapid and accurate DL tool to quantify the FMAA. Considerable variation with different measurement approaches for the FMAA supports that patient-specific anatomy and surgeon-dependent technique must be accounted for when correcting for the FMAA using an intramedullary guide. The angle between the mechanical and anatomical axes of the femur fell outside the range of 5.0° (SD 2.0°) for nearly a quarter of patients.
PURPOSE: The primary purpose of the study was to use pre-revision total knee arthroplasty (TKA) computer-tomography (CT)-images to analyse typical tibial bone defects and create a new schematic three-dimensional (3D)-classification system. The secondary purpose was to investigate the association between defect size and implant selection at the time of revision surgery. METHODS: Eighty-four patients with preoperative CT-scans underwent revision of a primary TKA. CT-image segmentation with the 3D-Slicer Software was performed retrospectively, and a new three-dimensional classification system was used to grade tibial bone defects. The location of tibial bone defects was recorded for all cases. Volumetric 3D bone defect measurements were used to investigate the association between the bone defect volume, the indication for rTKA, and the use of modular revision components. The t-test, the Mann-Whitney-U test, and the Fisher's exact-test were used for group comparisons, and the Kruskal-Wallis test was used for multiple group comparisons. RESULTS: The most common anatomic regions for both contained and uncontained tibial bone defects were the anteromedial epiphysis (N = 50; mean epiphyseal-defect: 5.9 cm³) and metaphysis (N = 15; mean metaphyseal-defect: 9.6 cm³). A significant association was found between patients with preoperative metaphyseal defects (N = 22) and the use of tibial augments (N = 7) (p = 0.04). The use of cones/sleeves was associated with a significantly increased 3D-CT volume of the preoperative metaphyseal bone defects (p = 0.04). Patients with osteoporosis had significantly larger volumetric defects in the metaphysis (p = 0.01). CONCLUSION: Our results emphasise the importance of considering the three-dimensional nature of tibial defects in rTKA. The findings suggest that an understanding of the volume of the defect size through CT imaging can predict the need for augments and cones/sleeves and, especially in patients with osteoporosis can help the surgeon identify larger metaphyseal defects and ensure optimal metaphyseal fixation through appropriate implant selection. LEVEL OF EVIDENCE: Level III, retrospective cohort study.
Arthroplasty, Replacement, Knee , Knee Prosthesis , Osteoporosis , Humans , Arthroplasty, Replacement, Knee/methods , Retrospective Studies , Prosthesis Design , Tibia/diagnostic imaging , Tibia/surgery , Reoperation/methods , Osteoporosis/etiology , Osteoporosis/surgery , Knee Joint/diagnostic imaging , Knee Joint/surgery
The John N. Insall Knee Society Traveling Fellowship selects four international arthroplasty or sports fellowship-trained orthopaedic surgeons to spend 1 month traveling to various Knee Society members' joint replacement and knee surgery centers in North America. The fellowship aims to foster research and education and shares ideas among fellows and Knee Society members. The role of such traveling fellowships on surgeon preferences has yet to be investigated. A 59-question survey encompassing patient selection, preoperative planning, intraoperative techniques, and postoperative protocols was completed by the four 2018 Insall Traveling Fellows before and immediately after the completion of traveling fellowship to assess anticipated practice changes (e.g., initial excitement) related to their participation in a traveling fellowship. The same survey was completed 4 years after the completion of the traveling fellowship to assess the implementation of the anticipated practice changes. Survey questions were divided into two groups based on levels of evidence in the literature. Immediately after fellowship, there was a median of 6.5 (range: 3-12) anticipated changes in consensus topics and a median of 14.5 (range: 5-17) anticipated changes in controversial topics. There was no statistical difference in the excitement to change consensus or controversial topics (p = 0.921). Four years after completing a traveling fellowship, a median of 2.5 (range: 0-3) consensus topics and 4 (range: 2-6) controversial topics were implemented. There was no statistical difference in the implementation of consensus or controversial topics (p = 0.709). There was a statistically significant decline in the implementation of changes in consensus and controversial preferences compared with the initial level of excitement (p = 0.038 and 0.031, respectively). After the John N. Insall Knee Society Traveling Fellowship, there is excitement for practice change in consensus and controversial topics related to total knee arthroplasty. However, few practice changes that had initial excitement were implemented after 4-year follow-up. Ultimately, the effects of time, practice inertia, and institutional friction overcome most of the anticipated changes induced by a traveling fellowship.
Arthroplasty, Replacement, Knee , Orthopedic Procedures , Surgeons , Humans , Fellowships and Scholarships , Knee Joint
BACKGROUND: While robotic-assisted total hip arthroplasty (RA-THA) has been associated with improved accuracy of component placement, the perioperative and early postoperative outcomes of fluoroscopy-based RA-THA systems have yet to be elucidated. METHODS: This retrospective cohort analysis included a consecutive series of patients who received manual, fluoroscopy-assisted THA (mTHA) and fluoroscopy-based RA-THA at a single institution. We compared rates of complications within 90 days of surgery, length of hospital stay (LOS), and visual analog scale (VAS) pain scores. RESULTS: No differences existed between groups with respect to demographic data or perioperative recovery protocols. The RA-THA cohort had a significantly greater proportion of outpatient surgeries compared to the mTHA cohort (37.4% vs. 3.8%; p < 0.001) and significantly lower LOS (26.0 vs. 39.5 h; p < 0.001). The RA-THA cohort had a smaller 90-day postoperative complication rate compared to the mTHA cohort (0.9% vs. 6.7%; p = 0.029). The RA-THA cohort had significantly lower patient-reported VAS pain scores at 2-week follow-up visits (2.5 vs. 3.3; p = 0.048), but no difference was seen after 6-week follow visits (2.5 vs. 2.8; p = 0.468). CONCLUSION: Fluoroscopy-based RA-THA demonstrates low rates of postoperative complications, improved postoperative pain profiles, and shortened LOS when compared to manual, fluoroscopy-assisted THA.
Arthroplasty, Replacement, Hip , Robotic Surgical Procedures , Humans , Arthroplasty, Replacement, Hip/methods , Retrospective Studies , Robotic Surgical Procedures/methods , Treatment Outcome , Fluoroscopy , Postoperative Complications , Pain, Postoperative
BACKGROUND: The radiographic assessment of bone morphology impacts implant selection and fixation type in total hip arthroplasty (THA) and is important to minimize the risk of periprosthetic femur fracture (PFF). We utilized a deep-learning algorithm to automate femoral radiographic parameters and determined which automated parameters were associated with early PFF. METHODS: Radiographs from a publicly available database and from patients undergoing primary cementless THA at a high-volume institution (2016 to 2020) were obtained. A U-Net algorithm was trained to segment femoral landmarks for bone morphology parameter automation. Automated parameters were compared against that of a fellowship-trained surgeon and compared in an independent cohort of 100 patients who underwent THA (50 with early PFF and 50 controls matched by femoral component, age, sex, body mass index, and surgical approach). RESULTS: On the independent cohort, the algorithm generated 1,710 unique measurements for 95 images (5% lesser trochanter identification failure) in 22 minutes. Medullary canal width, femoral cortex width, canal flare index, morphological cortical index, canal bone ratio, and canal calcar ratio had good-to-excellent correlation with surgeon measurements (Pearson's correlation coefficient: 0.76 to 0.96). Canal calcar ratios (0.43 ± 0.08 versus 0.40 ± 0.07) and canal bone ratios (0.39 ± 0.06 versus 0.36 ± 0.06) were higher (P < .05) in the PFF cohort when comparing the automated parameters. CONCLUSIONS: Deep-learning automated parameters demonstrated differences in patients who had and did not have early PFF after cementless primary THA. This algorithm has the potential to complement and improve patient-specific PFF risk-prediction tools.
