National trends in musculoskeletal urgent care centers: Improved Medicaid access from 2019 to 2023.

Musculoskeletal urgent care centers (MUCCs) are an increasingly common alternative to emergency departments for patients with orthopedic injuries. As there is a lack of longitudinal data regarding MUCCs' impact on the emergency health care system, our study seeks to understand recent trends in MUCC growth and their acceptance of Medicaid insurance. Over the last 6 years, at 2-year intervals (2019, 2021, and 2023), we performed a search to identify all MUCCs in the United States. We determined the affiliation and Medicaid acceptance status of all MUCCs, including those that closed/opened between 2019, 2021, and 2023, to analyze trends in MUCC availability and Medicaid acceptance. In 2019, there were 558 MUCCs, which increased to 596 MUCCs in 2021 and then decreased to 555 MUCCs in 2023, representing a growth and then decline of approximately 7%. Overall, since June 2019, 90 MUCCs have opened and 95 MUCCs have closed. Medicaid acceptance increased nationally between 2019 and 2023, from 58% to 71%. Medicaid acceptance increased for both nonaffiliated and privately affiliated MUCCs. Medicaid acceptance has increased nationally from 2019 to 2023, while MUCC availability has gone through a period of growth and then reversion to 2019 levels. As MUCCs have demonstrated limited Medicaid acceptance previously, it is promising that Medicaid acceptance has improved and MUCCs are providing patients with an additional avenue to access orthopedic care.

A Single Center Exploratory Survey of Patients and Nurses on post-Surgical Oral Opioid Delivery Through Patient-Controlled Analgesia.

Background: The most common route of opioid delivery is nurse-administered pills. However, there are numerous challenges such as nursing burden, opioid diversion, medication delay, and patient dissatisfaction. In this study, we conducted two surveys, first to assess patients' and nurses' opinions on the current administration of opioids in pill form, followed by their attitudes towards an innovative concept of oral medication delivery based on a medical device currently undergoing research and development within the University, patient-controlled dispenser and deactivator (PCDD) that allows patients to self-administer liquid oral opioids on demand based on physician prescription. Methods: Questionnaires were developed, verified and deployed to assess nurse and post-surgical patient opinions on the current administration of opioids in pill form, as well as the proposed new concept of patient -controlled administration of oral liquid medication via an illustration of PCDD, from September 2022 through July 2023 at a major academic tertiary care center. Quantitative and qualitative data were collected from postoperative patients and nurses from surgical specialties including General Surgery, Surgical Oncology, Trauma Surgery, Orthopedics, and Neurosurgery. Results: Forty-three patients and 53 nurses were interviewed. Seventy percent of patients frequently called nurses for pain medication post-surgery 1-4 times daily, and 32% of patients were told each day by nurses that they could not receive medication because they were not due yet. Medication delay caused 24% of patients to worry about nursing availability for medication delivery. Likewise, nurses reported that half of patients receive delayed medication (22 minutes median delay time) and half of nursing time was spent administering pain medication. Nurses expressed moderate satisfaction with their current delivery of medication (median satisfaction score 6.5 out of 10). When being introduced to the concept of PCDD via a product illustration, 15% of patients said that they prefer liquid medication and 51% said they prefer PCDD or were interested in trying it. Conclusion: Nurse-administered pills are a common but suboptimal method for postoperative pain management. Based on patient and nurse feedback, patient controlled self-administered liquid oral opioid delivery is conceptually innovative, practically viable and potentially a preferred alternative for timely and less nurse-exhaustive pain management.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Payer Status and Medication Management-Part Six of the Movement Is Life Special ONJ Series.

This article is the sixth in the Movement is Life series and focuses on insurance coverage and medication management in the perioperative period, 2 tangentially related variables that affect patient outcomes. Our aim is to use current practices and literature to develop recommendations for nurse navigators' execution of preoperative optimization protocols related to payer status and medication management. Discussions with nurse navigators and a literature search were used to gather information and develop recommendations specific to optimizing payer status and medication management. Nurse navigators connected patients to resources and provided education regarding financial concerns and medications, and findings from the literature discussed insurance status among TJA patients. Nurse navigators can contribute to payer status and medication management optimization by providing patient education and resource referrals. In addition, we recommend conducting repeated medication reconciliation and developing awareness of financial resources and perioperative medication management guidelines.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Mental Health and Housing Status-Part Five of the Movement Is Life Special ONJ Series.

Mental health and housing status have the potential to impact total joint arthroplasty (TJA) outcomes and are common TJA eligibility criteria that prevent patients from receiving surgery. Our aim was to formulate recommendations for how nurse navigators can assist patients with managing mental health and housing concerns. Through discussions with nurse navigators and a literature search across two databases, we gathered information regarding the optimization of mental health and housing status among TJA patients. We observed a lack of standardized protocols for addressing these concerns and literature supporting an increased focus on mental health and housing status, indicating the potential for greater nurse navigator involvement in developing and implementing protocols. We recommend nurse navigators use screening tools to identify mental health and housing concerns and offer the suggested resources to support patients in an effort to improve postoperative outcomes and decrease surgical risks.

Using preoperative planning software to assess the effect of head length on prosthetic range of motion in a high-risk population: a three-dimensional modeling study.

PURPOSE: Concurrent use of minus heads with tapered stems in total hip arthroplasty (THA) decreases the prosthetic range of motion (pROM). Three-dimensional preoperative templating can simulate the location of the impingement by taking the hip through a virtual pROM. This enables surgeons to simulate how modifying the type of implant, orientation, and position influences impingement. We hypothesized that CT-based modeling would result in a decrease in the pROM, thereby increasing the risk of impingement when minus heads are used. METHODS: Forty-three patients who underwent robotic-assisted primary THAs were included. Prosthetic head diameter (32/36-mm) and head length (minus/zero/plus) were the predictors. Maximum external rotation at full hip extension and internal rotation at 90° and 100° of flexion prior to prosthetic impingement were the outcome variables. A CT-based preoperative planning software was used for pROM estimation and impingement detection. RESULTS: Significant decreases in pROM were found for both head diameters as the head length decreased and was more pronounced in external rotation during full hip extension (changes of 2.8-3.4° for the 32-mm head and 1.6-2.8° for the 36-mm head (p = 0.00011)). The magnitude of loss in pROM when using a minus head was larger than the gain provided by a plus head in tapered stems (p < 0.0001). CONCLUSION: Head length affects the offset and pROM. When the use of minus heads or smaller heads is indicated, 3D preoperative templating for assessing postoperative pROM and impingement provides surgeons with options to consider alternate surgical plans offering additional assurance and protection from dislocation.

Outcomes of Distal Third Femur Fractures in Patients 18 Years and Older: A Pilot Study.

INTRODUCTION: The selection of the most optimal fixation method for fractures of the distal femur, whether intramedullary nail (NL), lateral locking plate (PL), or nail/plate (NP) is not always clear. This study retrospectively evaluates surgical patients with distal femur fractures and introduces a pilot study using cluster analysis to identify the most optimal fracture fixation method for a given fracture type. METHODS: This is a retrospective cohort study of patients 18 years and older with an isolated distal femur fracture who presented to our Level-1 trauma center between January 1, 2012, and December 31, 2022, and obtained NL, PL, or NP implants. Patients with polytrauma and those without at least six months of follow-up were excluded. A chart review was used to obtain demographics, fracture classification, fixation method, and postoperative complications. A cluster analysis was performed. The following factors were used to determine a successful outcome: ambulatory status pre-injury and 6-12 months postoperatively, infection, non-union, mortality, and implant failure. RESULTS: A total of 169 patients met inclusion criteria. No statistically significant association between the fracture classification and fixation type with overall outcome was found. However, patients treated with an NP (n = 14) had a success rate of 92.9% vs only a 68.1% success rate in those treated with a PL (n = 116) (p = 0.106). The most notable findings in the cluster analysis (15 total clusters) included transverse extraarticular fractures demonstrating 100% success if treated with NP (n = 6), 50% success with NL (n=2), and 78.57% success with PL fixation (n=14). NP constructs in complete articular fractures demonstrated success in 100% of patients (n = 5), whereas 77.78% of patients treated with NL (n = 9) and 61.36% of those treated with PL (n = 44). CONCLUSIONS: Plate fixation was the predominant fixation method used for distal third femur fractures regardless of fracture classification. However, NP constructs trended towards improved success rates, especially in complete intraarticular and transverse extraarticular fractures, suggesting the potential benefit of additional fixation with these fractures. Cluster analysis provided a heuristic way of creating patient profiles in patients with distal third femur fractures. However, a larger cohort study is needed to corroborate these findings to ultimately develop a clinical decision-making tool that also accounts for patient specific characteristics.

Sustentaculum fracture fixation with lateral plate or medial screw fixation are equivalent.

BACKGROUND: Fixation of sustentaculum tali fractures is important to maintain the biomechanical function of the subtalar joint. A common method of fixation is securing the sustentacular fragment by way of a laterally based locking plate (LP). A medial approach with a single screw (MS) has been proposed as an alternative method of fixation. METHODS: Five pairs of formalin-preserved cadaveric ankles with the subtalar joint and interosseous ligaments intact ("osseous cadavers") and four pairs of fresh-frozen cadaveric ankles with soft-tissue preserved dissected from mid-tibia down ("soft tissue cadavers") were used in the study. The left ankle was randomly assigned to one of the two fixation methods (LP or MS), while the right ankle was the opposite. These same steps for fixation were repeated for six synthetic ankle models. All models were loaded with a body mass of 80 kg. Statistical differences between LP and MS stiffness were determined using a paired t-test in cadavers and un-paired t-tests in synthetic ankles. RESULTS: For osseous cadaveric ankles, LP demonstrated a mean stiffness of 232.95(SD: 59.96) N/mm, while MS was 239.72(SD:131.09) N/mm (p = 0.9293). For soft tissue cadaveric ankles, LP mean stiffness was 133.58(SD:37.84) N/mm, while MS was 134.88(SD:20.75) N/mm (p = 0.9578). For synthetic ankles, LP mean stiffness was 220.40(SD:81.93) N/mm, while MS was 261.50(SD:100.21) N/mm (p = 0.6116). CONCLUSIONS: Across all three models, there was no significant difference between LP and MS methods. Retrospective observational studies are recommended to assess patient outcomes from each of the methods.

Fabricating patient-specific 3D printed drill guides to treat femoral head avascular necrosis.

BACKGROUND: Femoral head avascular necrosis (AVN), or death of femoral head tissue due to a lack of blood supply, is a leading cause of total hip replacement for non-geriatric patients. Core decompression (CD) is an effective treatment to re-establish blood flow for patients with AVN. Techniques aimed at improving its efficacy are an area of active research. We propose the use of 3D printed drill guides to accurately guide therapeutic devices for CD. METHODS: Using femur sawbones, image processing software, and 3D modeling software, we created a custom-built device with pre-determined drill trajectories and tested the feasibility of the 3D printed drill guides for CD. A fellowship trained orthopedic surgeon used the drill guide to position an 8 ga, 230 mm long decompression device in the three synthetic femurs. CT scans were taken of the sawbones with the drill guide and decompression device. CT scans were processed in the 3D modeling software. Descriptive statistics measuring the angular and needle-tip deviation were compared to the original virtually planned model. RESULTS: Compared to the original 3D model, the trials had a mean displacement of 1.440 ± 1.03 mm and a mean angle deviation of 1.093 ± 0.749º. CONCLUSIONS: The drill guides were demonstrated to accurately guide the decompression device along its predetermined drill trajectory. Accuracy was assessed by comparing values to literature-reported values and considered AVN lesion size. This study demonstrates the potential use of 3D printing technology to improve the efficacy of CD techniques.

Femoral Head Core Decompressions: Characterization of Subsequent Conversion to Total Hip Arthroplasty and Related Complications.

BACKGROUND: Core decompression is a minimally invasive joint-preserving approach for early-stage osteonecrosis. The rate at which core decompression patients require total hip arthroplasty (THA) and rates of perioperative adverse outcomes have not been well-characterized. METHODS: Adult patients undergoing core decompression and/or THA with osteonecrosis of the femoral head were identified from the 2015 to 2021 Q3 PearlDiver M157 database. Those undergoing THA without or with antecedent core decompression were identified and matched 4:1 on age, sex, and Elixhauser Comorbidity Index. Postoperative 90-day adverse events were compared with multivariable analysis. Five-year rates of revision, dislocation, and periprosthetic fracture were compared by the Kaplan-Meier curve and log-rank tests. RESULTS: Core decompressions were identified for 3,025 patients of whom 387 (12.8%) went on to THA within 5 years (64% within the first year). The median time from initial core decompression to THA was 252 days. For THA, 26,209 adults were identified and 387 had prior core decompression. After matching, there were 1,320 without core decompression and 339 with core decompression. No statistically significant differences were observed in 90-day postoperative adverse events or 5-year rates of revision, dislocation, or periprosthetic fracture. CONCLUSION: Core decompression may be an option for patients with osteonecrosis and does not seem to affect THA outcomes if required later.

Using Computed Tomography-Based Three-dimensional Modeling and Computer Navigation for Minimally Invasive Core Decompression and Adjuvant Orthobiologic Therapy of Femoral Head Avascular Necrosis.

Avascular necrosis of the femoral head is a debilitating condition that can lead to femoral head collapse. Core decompression with adjuvant cellular therapies, such as bone marrow aspirate concentrate, delays disease progression and improves outcomes. However, inconsistent results in the literature may be due to limitations in surgical technique and difficulty in targeting the necrotic lesions. Here, we present a surgical technique utilizing computed tomography-based three-dimensional modeling and instrument tracking to guide the therapy to the center of the lesion. This method minimizes the number of attempts to reach the lesion and confirms the three-dimensional positioning of the instrumentation within the lesion. Our technique may improve the outcomes of core decompression and adjuvant therapy and prevent or delay hip collapse in patients with femoral head avascular necrosis.

The feasibility of a novel 3D-Printed patient specific cutting guide for extended trochanteric osteotomies.

BACKGROUND: The extended trochanteric osteotomy (ETO) is a surgical technique utilized to expose the intramedullary canal of the proximal femur, protect the soft tissues and promote reliable healing. However, imprecise execution of the osteotomy can lead to fracture, soft tissue injury, non-union, and unnecessary morbidity. We developed a technique to create patient specific, 3D-printed cutting guides to aid in accurate positioning of the ETO and improve osteotomy quality and outcomes. METHODS: Patient specific cutting guides were created based on CT scans using Synopysis Simpleware ScanIP and Solidworks. Custom 3D printed cutting guides were tested on synthetic femurs with foam cortical shells and on cadaveric femurs. To confirm accuracy of the osteotomies, dimensions of the performed osteotomies were compared to the virtually planned osteotomies. RESULTS: Use of the patient specific ETO cutting guides resulted in successful osteotomies, exposing the femoral canal and the femoral stem both in synthetic sawbone and cadaveric testing. In cadaveric testing, the guides allowed for osteotomies without fracture and cuts made using the guide were accurate within 6 percent error from the virtually planned osteotomy. CONCLUSION: The 3D-printed patient specific cutting guides used to aid in ETOs proved to be accurate. Through the iterative development of cutting guides, we found that a simple design was key to a reliable and accurate guide. While future clinical trials in human subjects are needed, we believe our custom 3D printed cutting guide design to be effective at aiding in performing ETOs for revision total hip arthroplasty surgeries.

Off-the-Shelf Tibial Cone Sizes May Not Accommodate All Patients' Bone Morphology and May Lead to Cortical Breaches in Revision Total Knee Arthroplasty: A 3D Modeling Study.

Background: In revision total knee arthroplasty, tibial cones have demonstrated improved longevity and reduced incidence of aseptic loosening. Several currently available "off-the-shelf" (OTS) cone systems may not have sizes to accommodate all patient bone morphologies. Methods: Computed tomographies from one hundred primary total knee arthroplasty patients and dimensions of 4 OTS cones were obtained. Press-fit stems were positioned in 3D tibia models to fit the diaphyseal trajectory. Cones were positioned around the stem at 1, 6, and 13 mm resections measured from the trough of the medial tibial plateau, simulating proximal tibial cuts and bone loss. Tibias were examined for cortical breaching following modeled cone preparation. Results: Increased rate of breaching was observed as size and depth of the cone increased. In 2/49 (4.1%) male and 19/46 (41.3%) female tibias, cones could not be positioned without breaching. No breaches were found in 22/49 (45.0%) male and 5/46 (10.9%) female tibias. For every 1 centimeter increase in patient height, odds of breaching decreased by 12% (odds ratio: 0.88, confidence interval: 0.84, 0.92). For every size increase in cone width, odds of breaching increased by 34% (odds ratio: 1.34, confidence interval: 1.28, 1.47). Placing cones deeper also increased breaching compared to the 1 mm cut. Conclusions: In revision total knee arthroplasty, smaller OTS or custom tibial cones may be needed to fit a patient's proximal tibial geometry. This is especially true in patients not accommodated by the OTS cone sizes we tested, which impacted shorter patients and/or those with substantial bone loss requiring more tibial resection and deeper cone placement. Use of smaller or custom tibial cones should be considered where indicated.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Obesity and Malnutrition-Part Four of the Movement Is Life Special ONJ Series.

Obesity and malnutrition affect many patients with osteoarthritis and can predispose patients to worse outcomes after total joint arthroplasty (TJA). However, these modifiable risk factors can be addressed in preoperative optimization programs driven by nurse navigators. Our aim is to provide resources and recommendations for nurse navigators when addressing obesity and malnutrition among TJA patients. In addition to discussions with nurse navigators regarding obesity and malnutrition, a literature review was conducted to assess the current practice standards for management. Nurse navigators often had difficulty implementing long-term interventions, but interventions in the literature included medical and bariatric treatments for obesity and more targeted assessment of nutrition status. These findings are incorporated into our recommendations for nurse navigators. Addressing obesity and malnutrition in preoperative optimization can contribute to improved outcomes, as has been demonstrated in current practice and in the literature.

A review of the design, manufacture, and outcomes of custom total joint replacement implants available in the United States.

Custom total joint replacement (TJA) implants, specifically designed and manufactured for each patient, have emerged as surgeons seek to improve functional outcomes of primary total joint replacement, as well as treat patients with complex primary deformities, bone defects, and revision surgeries. The purpose of this review is to present the various custom total hip and knee arthroplasty implants available in the United States for primary and revision cases, so that surgeons can understand the design considerations and manufacturing processes of custom implants, as well as their performance compared to standard implants.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Diabetes and Cardiovascular Disease-Part 3 of the Movement Is Life Special ONJ Series.

Diabetes and cardiovascular disease are some of the most common risk factors for complications after total joint arthroplasty (TJA). Preoperative optimization programs are dependent on nurse navigators for coordination of interventions that improve patients' health and surgical outcomes. This article uses information regarding the current practices for diabetes and cardiovascular disease management to provide recommendations for nurse navigators when managing these risk factors prior to TJA. We consulted nurse navigators and conducted a literature review to learn about strategies for addressing diabetes and cardiovascular disease in preoperative optimization programs. Nurse navigators can play a critical role in addressing these conditions by providing patient education and implementing preoperative optimization protocols that incorporate discussion regarding guidelines for diabetes and cardiovascular disease management prior to surgery. This article shares recommendations and resources for nurse navigators to help address diabetes and cardiovascular disease as part of preoperative optimization programs.

Some Offset Restoration Options Can Paradoxically Lead to Decreased Range of Motion in Primary Total Hip Arthroplasty: A 3-Dimensional Computer Simulation Study.

BACKGROUND: In total hip arthroplasty (THA), femoral offset restoration results in optimal biomechanics and range of motion (ROM) without bone-bone impingement. We hypothesized that differences in implant design features significantly affect bone-bone impingement risk in primary THA. METHODS: This retrospective computer simulation study included a cohort of 43 primary robotic arm-assisted THA. Considering sagittal pelvic tilt, we measured the maximum external rotation at 0° hip flexion and the maximum internal rotation at both 90° and 100° hip flexion before any bone-bone impingement occurred. To influence the offset, we included neutral or extended polyethylene liners, neutral or plus prosthetic heads, standard or high-offset stems, and stems with 132° or 127° neck angles. RESULTS: Extended polyethylene liner use resulted in decreased bone-bone impingement for both stems but also decreased prosthetic ROM in hip extension (mean -4.5 to 5°, range -10 to 0°) and hip flexion (mean -3 to 3.7°, range -10 to 0°) due to decreases in head diameter. Using a plus head or different stem offset/neck angle options resulted in either (1) no improvement in ROM (stem 1: 60%; stem 2: 28%) or (2) a paradoxical increase in bone-bone impingement (stem 1 with 127°: 19% and stem 2 with high offset option: 7%). CONCLUSION: Counterintuitively, a subset of patients experience a paradoxical increase in bone-bone impingement when transitioning from standard to high-offset or varus necks due to the pelvic and proximal femoral bone shape. For this group of patients, preoperative personalized 3-dimensional modeling may help guide implant choice for optimizing outcomes.

Fabricating Patient-Specific 3D Printed Drill Guides to Treat Femoral Head Avascular Necrosis.

Background: Femoral head avascular necrosis (AVN), or death of femoral head tissue due to a lack of blood supply, is a leading cause of total hip replacement for non-geriatric patients. Core decompression (CD) is an effective treatment to re-establish blood flow for patients with AVN. Techniques aimed at improving its efficacy are an area of active research. We propose the use of 3D printed drill guides to accurately guide therapeutic devices for CD. Methods: Using femur sawbones, image processing software, and 3D modeling software, we created a custom-built device with pre-determined drill trajectories and tested the feasibility of the 3D printed drill guides for CD. A fellowship trained orthopedic surgeon used the drill guide to position an 8 ga, 230 mm long decompression device in the three synthetic femurs. CT scans were taken of the sawbones with the drill guide and decompression device. CT scans were processed in the 3D modeling software. Descriptive statistics measuring the angular and needle-tip deviation were compared to the original virtually planned model. Results: Compared to the original 3D model, the trials had a mean displacement of 1.440±1.03 mm and a mean angle deviation of 1.093±0.749°. Conclusions: The drill guides were demonstrated to accurately guide the decompression device along its predetermined drill trajectory. Accuracy was assessed by comparing values to literature-reported values and considered AVN lesion size. This study demonstrates the potential use of 3D printing technology to improve the efficacy of CD techniques.

The Use of Computer Navigation and Robotic Technology in Complex Total Hip Arthroplasty.

Computer assisted surgical (CAS) navigation and robotic-assisted total hip arthroplasty (THA) have the potential to improve the reproducibility of accurate component positioning and facilitate complex cases, including revision and preoperative deformity. Numerous studies, including multiple comparing technology with conventional THA control groups, suggest that CAS navigation may improve component accuracy in cases of deformity such as hip dysplasia and significant leg length discrepancy. Revision THA data is also encouraging but limited. The functional benefits compared to conventional techniques remain unclear. The evidence for robot-assisted THA in complex cases is more limited but also demonstrates utility. For complex cases, studies comparing results with conventional THA are not yet available. The limitations of these systems, including cost, operative time, learning curves, and possible complications, require further study. The available data for CAS navigation and robotic-assisted THA indicates that they may play a role in complex deformity and revision cases. Further high-quality randomized studies should be undertaken.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Substance Use.

Substance use is one of the most common risk factors contributing to complications following total joint arthroplasty. Preoperative optimization programs can help patients modify or stop substance use. The purpose of this study was to provide recommendations and resources that will help nurse navigators standardize and improve preoperative optimization protocols regarding substance use. In a semistructured format, we asked nurse navigators how smoking, alcohol use, and opioid use were addressed. We conducted a literature review and combined findings with nurse navigator reports to create practice recommendations. We recommend consistently referring patients who smoke to smoking cessation programs; using validated screening tools to evaluate alcohol use and involving internists in caring for patients at risk for withdrawal; and involving pain specialists and local resources to assist patients who use opioids. There is a breadth of resources for managing substance use that nurse navigators can utilize to support stronger and more consistent preoperative optimization protocols.

Three-Dimensional Printing of Models of Patellofemoral Joint Articular Cartilage in Patients With Patella Instability for Observing Joint Congruity.

Three-dimensional (3D) modeling and printing are increasingly used in the field of orthopaedic surgery for both research and patient care. One area where they are particularly helpful is in improving our understanding of the patellofemoral (PF) joint. Heretofore, morphological studies that use 3D models of the PF joint have primarily been based on computed tomography imaging data and thus do not incorporate articular cartilage. Here, we describe a method for creating 3D models of the articular surfaces of the PF joint based on magnetic resonance imaging. Models created using this technique can be used to improve our understanding of the morphology of the articular surfaces of the PF joint and its relationship to joint pathologies. Of particular interest is our finding of articular congruity in printed articular cartilage surfaces of dysplastic PF joints of recurrent patella dislocators.