Femoral Resection Research Articles

Rehabilitation Management of a Pediatric Patient with Modified Van Nes Prosthesis after Type B-IIIA Hip Rotationplasty: A Case Report

Van Nes rotationplasty has gained popularity as a surgical treatment for malignant bone tumors without resorting to amputation. However, the nature of the surgery poses unique challenges in the rehabilitation management in order to optimize safety and functional mobility. We describe a case of a 6-year-old female with Ewing’s sarcoma of the right femur who underwent Van Nes Type BIIIA rotationplasty. This procedure involved a complete femoral resection, with the tibia and the foot rotated by 180 degrees and the lateral tibial plateau placed into the acetabulum that is expected to remodel to form a neo-hip joint. The patient was referred to rehabilitation medicine and was eventually admitted due to impairment in mobility secondary to the surgery. The goal was to achieve K-1 level of function. This case demonstrates that the rehabilitation management of a child with Type B-IIIA rotationplasty using a modified Van Nes prosthesis requires a comprehensive multidisciplinary approach.

A survey to determine the zone of equipoise for the Proximal FEmur Resection or Internal Fixation fOR Metastases (PERFORM) randomized controlled trial.

The objective of this study was to establish a zone of clinical equipoise for the Proximal FEmur Resection or Internal Fixation fOR Metastases (PERFORM) randomized controlled trial, which will compare resection and endoprosthetic reconstruction to internal fixation for skeletal metastases of the proximal femur. A survey was developed, piloted, and distributed to self-declared interested stakeholders in the PERFORM trial. The survey targeted orthopedic oncologists and was designed to assess patient and bone lesion characteristics that drive surgical decision-making in the treatment of skeletal metastases in the proximal femur. An Ethics Waiver was obtained at the lead academic institution and data was collected in the REDCap survey database. Responses were complete from 76 surgeons across North America, South America, Europe, Asia, and Africa. Response rate from self-declared interested stakeholders was 70%, with additional responses collected from a broader international audience. Responses indicate that a study population for which either resection and endoprosthetic reconstruction or internal fixation are acceptable options include (1) life expectancy at least 6months, (2) bone loss of no more than 75% and no less than 25%, and (3) minimal to moderate risk for perioperative complications. Ninety-three percent of respondents indicated that they would be interested in participating in the PERFORM trial. A preliminary zone of equipoise for the PERFORM trial includes patients with 25-75% bone loss, low to moderate risk of operative complications, and life expectancy of at least 6months. Further stakeholder discussions have finalized the PERFORM trial protocol prior to study initiation.

The Conversion of Unicompartmental Knee Arthroplasty to Total Knee Arthroplasty with Non-CT-Based Robotic Assistance: A Novel Surgical Technique and Case Series.

Robotic-assisted devices help provide precise component positioning in conversion of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA). A few studies offer surgical techniques for computed tomography (CT) based robotic-assisted conversion of UKA to TKA; however, no studies to date detail this procedure utilizing a non-CT-based robotic-assisted device. This article introduces a novel technique employing a non-CT-based robotic-assisted device (ROSA Knee System, Zimmer Biomet, Warsaw, IN) for converting UKA to TKA with a focus on its efficacy in gap balancing. We present three patients (ages 46-66 years) who were evaluated for conversion of UKA to TKA for aseptic loosening, stress fracture, and progressive osteoarthritis. Each patient underwent robotic-assisted conversion to TKA. Postoperative assessments at 6 months revealed improved pain, function, and radiographic stability. Preoperative planning included biplanar long leg radiographs to determine the anatomic and mechanical axis of the leg. After arthrotomy with a standard medial parapatellar approach, infrared reflectors were pinned into the femur and tibia, followed by topographical mapping of the knee with the UKA in situ. The intraoperative software was utilized to evaluate flexion and extension balancing and plan bony resections. Then, the robotic arm guided placement of the femoral and tibial guide pins and the UKA components were removed. After bony resection of the distal femur and proximal tibia, the intraoperative software was used to reassess the extension gap, and plan posterior condylar resection to have the flexion gap match the extension gap. The use of a non-CT-based robotic-assisted device in conversion of UKA to TKA is a novel technique and a good option for surgeons familiar with robotic-assisted arthroplasty, resulting in excellent outcomes at 6 months.

Finite element analysis of the Fibula's contribution to lower extremity torsional stiffness

AimsThe purpose of this article is to investigate the effects of the fibula on the torsional stiffness of the lower limb. A comprehensive model of the lower limb was constructed, including the resected femur, patella, tibia, fibula, and foot, with tendons and ligaments. Two configurations were developed, with and without the presence of the fibula, to evaluate the resulting stress state and consequently determine the contribution of the fibula to the torsional stiffness of the lower limb. MethodsThe finite element method was used to analyse how the fibula affects the stress distribution in the lower extremity under body weight loading and torsional forces. A detailed three-dimensional solid model of the lower extremity with and without the fibula was constructed. Loading conditions were imposed simulating an axial compressive load of 700 N applied to the upper extremity of the resected femur and a torsional load of 6000 Nmm applied to the proximal femur, and a fixed constraint was imposed on the foot. ResultsRemoving the fibula results in an increase in stress on all the tendons and ligaments tested. The increases ranged from 4 % (patellar tendon) to 21 % (lateral retinaculum). This suggests that the fibula plays a significant role in the distribution of mechanical stress in the lower extremity. The most affected structures are the lateral retinaculum and the posterior cruciate ligament, both with a 21 % increase in stress, suggesting that these structures may compensate more for the absence of the fibula. ConclusionThe fibula plays a critical role in maintaining the structural integrity and biomechanical function of the lower extremity. It acts as a lateral strut, contributing to the stability of the ankle and knee by providing an attachment point for several muscles and ligaments that are essential for coordinating complex movements and providing stability during dynamic activities.

Efficiency assessment of intelligent patient-specific instrumentation in total knee arthroplasty: a prospective randomized controlled trial

BackgroundIn total knee arthroplasty (TKA), the practical use of patient-specific instrumentation (PSI) has been reported previously with both advantage and disadvantage. The application of artificial intelligent (AI) forces overwhelmingly development of medical industries, while the impact of AI on PSI efficiency remains unknown. Thus, this study aimed to assess the efficiency of Intelligent-PSI (i-PSI) in TKA, compared with the conventional instrumentation-TKA (CI).Methods102 late-stage OA patients who met inclusive criteria were recruited in this prospective randomized controlled trial and separated into two groups (i-PSI vs. CI). In both groups, an AI preoperative planning engine was applied for surgery decision making. In CI group, conventional instrumentation was applied for bony resection, while resection of i-PSI group was completed with i-PSI. A convolutional neural network was applied to automatically process computer tomography images and thus produced i-PSI. With the help of three-dimension printing, the workflow of production was largely simplified. AI-driven preoperative planning guided resection and alignment decisions. Resection measurement, perioperative radiography and perioperative clinical outcomes were analyzed to verify efficiency of i-PSI.ResultsIn resection outcomes, smaller deviation of lateral and medial distal femoral resection were found in i-PSI group than CI group (P = 0.032 and 0.035), while no difference was found in other resection planes. In radiography outcomes, postoperative coronal alignments of i-PSI group, including postoperative Hip–knee–ankle axis (HKA) (P = 0.025), postoperative HKA outliners (P = 0.042), Femoral coronal alignment (FCA) (P = 0.019) and Joint line convergence angle (JLCA) (P = 0.043) showed closer to neutral position than CI group. Moreover, Femoral sagittal alignment (FSA) of i-PSI group showed closer to neutral position than CI group(P = 0.005). No difference was found in other alignments. In clinical outcomes, i-PSI group seemed to cost more surgical time than CI group (P = 0.027), while others showed no differences between the two groups.ConclusionIntelligent Patient-specific Instrumentation in TKA achieved simplified production flow than conventional PSI, while also showed more accurate resection, improved synthesis position and limb alignment than conventional instrumentation. Above all, this study proved that i-PSI being an applicable and promising tool in TKA.

Allograft-prosthesis composite after proximal femur bone tumor resection in pediatric age: Is it effective in preserving bone stock?

The purpose of the study was to answer the following questions. What was functional results of pediatric patients receiving a short stem allograft-prosthesis composite of the proximal femur? What was complication rate and revision-free implant survival? Was it possible to preserve the bone stock of the proximal femur in pediatric patients? We reviewed 10 pediatric patients treated with proximal femur resection for a primary bone tumor and reconstruction with short stem allograft-prosthesis composite, with at least 24 months follow-up. The median age was 9 years (4-13) at surgery. The mean resection length was 15 cm (6-29). In six cases, fixation was performed with a short plate positioned under the great trochanter while in four cases a long plate extended over the great trochanter was employed. Nine complications that required surgical revision were assessed in six patients (one wound dehiscence, two nonunions, two fractures, one acetabular wear, three hypometria), while allograft-prosthesis composite removal was required in three patients. The revision-free survival was 57% (95% confidence interval 33%-100%) at 5 and 10 years. The graft removal-free survival was 75% (95% confidence interval 50%-100%) at 5 and 10 years. The mean Musculo-Skeletal Tumor Society Score was 28 (20-30). Allograft-prosthesis composites with short stem and compression plate represents an effective reconstructive option after proximal femur resection for primary bone tumors in growing patients, preserving bone stock. The use of a compression plate extended over the greater trochanter seemed to reduce failure rate.

Comparison of cost and complications of primary total hip arthroplasty versus oncologic proximal femur replacement

Aims and objectiveProximal femur replacement (PFR) is most commonly performed after a large resection of the proximal femur to remove tumor and is known to have high complication rates and worse function than a primary total hip replacement (THA). Many surgeons feel that current billing practices fail to adequately differentiate this procedure from a THA. This study aims to examine patients undergoing a primary THA or oncologic PFR and compare the relative economic impact and complication rates between cohorts. Materials & methodsPatient data was queried using a national database, identifying non-pediatric patients who underwent a primary THA or oncologic PFR. Exclusionary criteria were implemented, resulting in two cohorts, each with 380 patients matched in a 1:1 manner controlling for age, gender, and Charlson Comorbidity Index. Utilizing 2022 billing data, oncologic PFRs generated an average of 41.03 RVUs and primary THAs generated 19.60 RVUs. Total hospital cost was used to generate a cost:RVU ratio for each cohort. Key systemic and joint complication rates were additionally compared between cohorts. ResultsThe oncologic PFR cohort had significantly higher 90-day rates of anemia, deep vein thrombosis, and prosthetic dislocation compared to the primary THA cohort. The 90-day median hospital cost for oncologic PFR was $28,562.21 with a cost:RVU ratio of $696:1. The corresponding median hospital cost for primary THA was $9667.72, with a cost:RVU ratio of $493:1. ConclusionHospitals incur more cost per RVU for an oncologic PFR than a primary THA. Relative to primary THA, reimbursement for oncologic PFR is under-evaluated.

Refractory Post-Operative Wound Infection by Arthrographis Kalrae: A Case Report and Review of Literature

Arthrographis kalrae (A. Kalrae) infections, although rare, have often demonstrated an extended clinical course. We report a case of refractory post-operative wound infection with A. Kalrae after radical soft tissue and femur resection following total femoral replacement. Identification of A. Kalrae was done based on detailed microscopic and phenotypic characteristics and biochemical tests. Additionally, it was confirmed with sequencing. Although antifungal therapy was started on the basis of the breakpoints observed, clinical failure was met. However, wound infection was subsequently controlled with extensive tissue debridement and a combination of antifungal drug therapy over a period of 33 weeks. The rarity of global data about such unusual fungal infections adds to diagnostic and therapeutic challenges.

The Role of a New Hinged Total Knee Arthroplasty System for Use in a Variety of Complex Knee Scenarios: A Case Series.

Hinged knee arthroplasties are commonly used in scenarios where there are major ligament deficiencies or bone loss around the knee. They are applicable in native knees with major deformities and during revisions. They can also be used as a salvage procedure after distal femoral resection. The new modular hinged device system, namely the Triathlon Hinge Knee (THK) System (Stryker, Mahwah, New Jersey), reflects the advancements of third-generation design and enhances surgical flexibility by allowing streamlined integration with the Triathlon Total Stabilized (TS) System (Stryker, Mahwah, New Jersey) and the Global Modular Replacement System (GMRS, Stryker, Mahwah, New Jersey). Additionally, the Triathlon Revision Tibial Baseplate (Stryker, Mahwah, New Jersey) has been launched as part of THK and is compatible with the Modular Rotating Hinge (MRH , Stryker, Mahwah, New Jersey) femur, which allows the Revision Baseplate to replace the existing tibial component while leaving the existing MRH Femoral Component in place. The Triathlon Revision Tibial Baseplate enables orthopaedic surgeons to use constrained or hinged prostheses, including both distal and total femoral replacement options, without changing the Tibial Baseplate. This is because the TS, MRH, THK, and GMRS femurs are compatible with the new Triathlon Revision Tibial Baseplate. Additionally, the system can be augmented with metaphyseal cone constructs to help provide a stable foundation for reconstruction. This report explores the application of a new modular hinged device system in various scenarios, starting with (1) complex primary hinged knee arthroplasty, followed by revision hinged knee arthroplasty cases including (2) failed TKA with medial collateral ligament (MCL) dysfunction, (3) severe arthrofibrosis post-TKA, (4) revisions for prosthetic joint infection, (5) extensor mechanism deficiency, and (6) arthrofibrosis with extensor mechanism disruption, concluding with a case of (7) distal femoral arthroplasty for periprosthetic fracture post-failed TKA.

SHORTENING OSTEOTOMIES OF THE FEMUR DURING TOTAL HIP ARTHROPLASTY FOR DEVELOPMENTAL HIP DYSPLASIA

Total hip arthroplasty (THA) for congenital hip dysplasia (CDH) presents a challenge. In high-grade CDH, key surgical targets include cup placement in the anatomical position and leg length equality. Lengthening of more than 4 cm is associated with sciatic nerve injury, therefore shortening osteotomies are necessary. We present our experience of different shortening osteotomies including advantages and disadvantages of each technique.89 hips, in 61 pts (28 bilateral cases), for high CDH were performed by a single surgeon from 1997 to 2022. 67 patients were female and 22 were male. Age ranged from 38 to 68 yrs. In all patients 5–8cm of leg length discrepancy (LLD) was present, requiring shortening femoral osteotomy. 12 patients underwent sequential proximal femoral resection with trochanteric osteotomy, 46 subtrochanteric, 6 midshaft, and 25 distal femoral osteotomies with simultaneous valgus correction were performed. All acetabular prostheses were placed in the true anatomical position. We used uncemented high porosity cups. Patients were followed up for a minimum of 12 months.All osteotomies healed uneventfully except 3 non-unions of the greater trochanter in the proximal femur resection group. No femoral shaft fractures in proximally based osteotomies. No significant LLD compared to the unaffected or reconstructed side. 2 patients suffered 3 and 5 degrees malrotation of the femur in the oblique sub-trochanteric group. 3 patients suffered transient sciatic nerve palsies.Shortening femoral osteotomies in the treatment of DDH are necessary to avoid injury to the sciatic nerve. In our series, we found transverse subtrochanteric osteotomies to be the most technically efficient, versatile and predictable in their clinical outcome, due to the ability to correct rotation and preserve the metaphyseal bone integrity, allowing for better initial stem stability. Distal femoral osteotomies allowed for controllable correction of valgus knee deformity.

Addressing sagittal plane imbalance in primary total knee arthroplasty.

Sagittal plane imbalance (SPI), or asymmetry between extension and flexion gaps, is an important issue in total knee arthroplasty (TKA). The purpose of this study was to compare SPI between kinematic alignment (KA), mechanical alignment (MA), and functional alignment (FA) strategies. In 137 robotic-assisted TKAs, extension and flexion stressed gap laxities and bone resections were measured. The primary outcome was the proportion and magnitude of medial and lateral SPI (gap differential > 2.0 mm) for KA, MA, and FA. Secondary outcomes were the proportion of knees with severe (> 4.0 mm) SPI, and resection thicknesses for each technique, with KA as reference. FA showed significantly lower rates of medial and lateral SPI (2.9% and 2.2%) compared to KA (45.3%; p < 0.001, and 25.5%; p < 0.001) and compared to MA (52.6%; p < 0.001 and 29.9%; p < 0.001). There was no difference in medial and lateral SPI between KA and MA (p = 0.228 and p = 0.417, respectively). FA showed significantly lower rates of severe medial and lateral SPI (0 and 0%) compared to KA (8.0%; p < 0.001 and 7.3%; p = 0.001) and compared to MA (10.2%; p < 0.001 and 4.4%; p = 0.013). There was no difference in severe medial and lateral SPI between KA and MA (p = 0.527 and p = 0.307, respectively). MA resulted in thinner resections than KA in medial extension (mean difference (MD) 1.4 mm, SD 1.9; p < 0.001), medial flexion (MD 1.5 mm, SD 1.8; p < 0.001), and lateral extension (MD 1.1 mm, SD 1.9; p < 0.001). FA resulted in thinner resections than KA in medial extension (MD 1.6 mm, SD 1.4; p < 0.001) and lateral extension (MD 2.0 mm, SD 1.6; p < 0.001), but in thicker medial flexion resections (MD 0.8 mm, SD 1.4; p < 0.001). Mechanical and kinematic alignment (measured resection techniques) result in high rates of SPI. Pre-resection angular and translational adjustments with functional alignment, with typically smaller distal than posterior femoral resection, address this issue.

A novel robotic surgical assistant for total knee arthroplasty has a learning curve ranging from 6 to 14 cases and exhibits high accuracy in tibial bone cuts

BackgroundThe adoption of robot-assisted total knee arthroplasty (TKA) aims to enhance the precision of implant positioning and limb alignment. Despite its benefits, the adoption of such technology is often accompanied by an initial learning curve, which may result in increased operative times. This study sought to determine the learning curve for the ROSA (Robotic Surgical Assistant) Knee System (Zimmer Biomet) in performing TKA and to evaluate the accuracy of the system in executing bone cuts and angles as planned. The hypothesis of this study was that cumulative experience with this robotic system would lead to reduced operative times. Additionally, the ROSA system demonstrated reliability in terms of the accuracy and reproducibility of bone cuts.MethodsIn this retrospective observational study, we examined 110 medical records from 95 patients who underwent ROSA-assisted TKA performed by three surgeons. We employed the cumulative summation methodology to assess the learning curves related to operative time. Furthermore, we evaluated the accuracy of the ROSA Knee System in performing TKA by comparing planned versus validated values for femoral and tibial bone cuts and angles.ResultsThe learning curve for the ROSA Knee System spanned 14, 14, and 6 cases for the respective surgeons, with operative times decreasing by 22 min upon reaching proficiency (70.8 vs. 48.9 min; p < 0.001). Significant discrepancies were observed between the average planned and validated cuts and angles for femoral bone cuts (0.4 degree ± 2.4 for femoral flexion, 0.1 degree ± 0.6 for femoral coronal alignment, 0.3 mm ± 1.2 for distal medial femoral resection, 1.4 mm ± 8.8 for distal lateral femoral resection) and hip–knee–ankle axis alignment (0.3 degree ± 1.9 )(p < 0.05) but not for tibial bone cuts. Differences between planned and validated measurements during the learning and proficiency phases were nonsignificant across all parameters, except for the femoral flexion angle (0.42 degree ± 0.8 vs. 0.44 degree ± 2.7) (p = 0.49).ConclusionThe ROSA Knee System can be integrated into surgical workflows after a modest learning curve of 6 to 14 cases. The system demonstrated high accuracy and reproducibility, particularly for tibial bone cuts. Acknowledging the learning curve associated with new robot-assisted TKA technologies is vital for their effective implementation.

Morphological Measurement and Clinical Significance of Abnormal Development of Distal Femur with Hemophilia Knee Arthritis: A Consideration on the Renewal of Total Knee Prosthesis.

The knee joint of hemophiliacs may face the result of local morphological changes due to long-term irritation of synovitis. This study aims to elucidate the morphological characteristics of distal femur in hemophilic arthritis (HA) and compare the compatibility of three types of prostheses with the anteroposterior (AP) and mediolateral (ML) dimensions of the femoral osteotomy surface. This study retrospectively and randomly selected 50 patients with HA registered for treatment at our hospital from June 2016 to August 2022 as the study subjects, with an equal number of male osteoarthritis (OA) patients and healthy male individuals set as the control group. This study used medical digitalization software to simulate osteotomies on the distal femur during total knee arthroplasties (TKA) for 50 patients with HA, OA patients, and the healthy population, respectively, and measure the morphological parameters to compare with three commonly used femoral components of TKA in clinical practice. The differences between the femur resection of anteroposterior and mediolateral (FRAP, FRML) osteotomy surface and the prosthesis's BOX-AP/ML were compared in three prostheses. One-way ANOVA and multiple Kruskal-Wallis H test were used for the normal or non-normal distribution data, and pairwise comparisons between groups were conducted using the Bonferroni method, and the linear correlation analysis was utilized to assess the relationship between section femoral morphological data and prosthesis parameters. In HA patients, the morphological characteristics of the distal femur were shown as shorter than femur AP (FAP), medial and lateral condyle anterior-posterior dimension (FMCAP, FLCAP), notch width (NW), posterolateral condyle height (PLCH), posteromedial condyle width (PMCW), and posterior condylar axis length (PCAL) dimension. They had comparatively smaller femur section aspect ratios (p < 0.005). They showed longer posterolateral condyle width (PLCW), anterior condyle mediolateral dimension (FRACML), anterolateral condyle height (ALCH), and femur resection anterior condylar mediolateral (FRACML) dimension (p < 0.005). They showed larger distal femur aspect ratio and resection aspect ratio (FAR, FRAR, p < 0.005). All selected prostheses showed ML undercoverage under similar AP dimensions, and ML undersizing of Attune systems was more obvious in three femoral prostheses. The distal femur morphological change of HA patient is shown as smaller AP dimension, narrow posterior condyle spacing, lower and shallower trochlear, thinner anterior condyle, wider and lower intercondylar notch and higher posterior-lateral condyle. The selected prostheses showed ML undercoverage under similar AP dimensions. This typical morphological tendency of the distal femur seems to warrant consideration in the process of knee joint prosthesis upgrading.

Gait analysis of patients undergoing knee endoprosthesis: functional differences between tibia and femur resections.

With the improvement in survival of patients undergoing knee reconstructive surgeries, the functional parameter became widely studied heading optimize and minimize motor sequelae. In patients undergoing knee endoprosthesis, proximal tibial or distal femoral resections affect the functioning of the knee extensor mechanism, with possible repercussions on gait. Seventeen patients were selected, divided into two groups, undergoing distal femoral or proximal tibial resection, and gait analysis examination was performed. Changes in gait velocity, cadence, step length, and alterations in the support and balance phase were observed. No major statistically significant differences were found in the kinetic and kinematic parameters between the operated groups. The study corroborates that although tibial resections have a higher theoretical risk of compromising the extensor mechanism, such data were not observed in the analyzed sample.

Paper 18: The Pendulum Has Swung: A 14-Year Analysis of Patients Presenting for Failed Hip Arthroscopy Shows Rising Incidence of Cam Over-Resection and Decreasing Incidence of Under-Resection

Background: There is a paucity of literature regarding prevalence of femoral resection in the setting of revision hip arthroscopy. Few studies have examined different types of resections and their presentation. Purpose: To describe the prevalence of femoral resection types in the setting of revision hip arthroscopy for residual femoroacetabular impingement syndrome (FAIS) symptomatology. Methods: A search of the institutional prospective registry was performed for patients who presented for evaluation of failed previous arthroscopy between February 2008 and June 2022, and subsequently underwent revision arthroscopy. AP and Dunn view radiographs were reviewed from our study population. On the basis of measurements on both radiographs, patients were divided into 3 categories: overresection (OR) in which the resection measured 5% or more of the femoral head diameter, underresection (UR) in which residual CAM morphology was found (alpha angle &gt;60°), and neutral resection, alpha angle less than 60° and no overresection. Both AP and Dunn radiographs were used to identify over- and under- resections. Results: A total of 622 hips were reviewed and measured on both AP and Dunn radiographs. Of the 622 hips, there were 373 right and 249 left hips. The average age was 33.7 ± 12.0, and the average body mass index (BMI) was 26.0 ± 5.2. Three hundred sixty-five hips were classified as UR and 265 hips as OR. The mean prevalence rates from 2008 to 2022 for neutral resection, over-resection and under-resection were 48.1%, 20.3%, and 31.6%, respectively. The prevalence rates of UR have decreased since 2008, while prevalence rates of OR have increased concomitantly. The steadily decreasing prevalence rates of UR was negatively correlated with the increasing OR ((R=-0.829, P&lt;.0001), as well as with neutral resections (R=-0.735, P=0.002). The ratio of UR to OR reversed entirely, from 4:1 in 2010, to 1: 2.3 ( P &lt; 0.00001) in 2020. Conclusions: Amongst patients presenting for failed hip arthroscopy over the last 14 years, the pendulum has swung from under-resection towards over-resection. Indeed, as of 2020, over-resections were more than twice as common as under-resections. This may be a result of heightened awareness in FAIS, and previous literature emphasizing the risks of under-resection. As we gain increased understanding of the risks of over-resection, the findings of this study highlight the importance of achieving an anatomical spherical resection.

The Patient Acceptable Symptom State (PASS) after proximal and distal femoral replacement

IntroductionFemoral megaprostheses are used for bone reconstruction surgery in patients with local tumors or who require multiple revisions. Patient reported outcome measures (PROMs) provide a subjective result and, like patient satisfaction, have become an integral part of the outcomes in orthopedics. However, the threshold of satisfaction (PASS: Patient Acceptable Symptom State) has not yet been defined in a French population after this type of arthroplasty. This led us to carry out a retrospective study on a population of patients who received a femoral reconstruction megaprosthesis in order to 1) define the PASS for the Harris Hip Score (HHS), Knee Society Score (KSS) and the Musculoskeletal Tumor Society score (MSTS), 2) study the complications. HypothesisThe PASS threshold for proximal femur and distal femur reconstruction prothesis for the HHS and the KSS, respectively, will be lower than the threshold for these same scores for primary arthroplasty. Materials and methodsForty-four patients who were operated on between 2009 and 2020 were included: 23 received a proximal femur prosthesis and 21 received a distal femur prosthesis. The PASS threshold was defined using an anchoring strategy by analyzing ROC curves for the HSS for the proximal femur, KSS for the distal femur and the MSTS for all the prostheses. Complications were classified according to Henderson. ResultsThe mean follow-up was 4.5 ± 3.6 (1–12.5) years. The PASS threshold was 47.5 (area under curve (AUC) 0.71 (0.45–0.97)) for the HHS, 69.5 (AUC 0.97 (0.92–1.0)) for the KSS knee and 62.5 (AUC 0.81 (0.61–0.99)) for the KSS function. Thirteen patients (29%) had complications, nine of whom required another surgery (20%). The most frequent were Henderson type 1 (soft tissue lesions, n = 5/44 [11%]) and type 2 (loosening, n = 5/44 [11%]) There was no relationship between satisfaction and postoperative complications (p = 0.071). DiscussionMost of the patients who undergo femoral resection and reconstruction (59%) are satisfied with their function, albeit reduced, despite a high complication rate (29%). Our hypothesis is confirmed for the PASS threshold for the HHS (47.5 versus 93) and the KSS knee and function (69.5 and 62.5 versus 85.5 and 72.5). Level of evidenceIV; retrospective observational single-center study.

Aggressive granulomatous pseudotumor following total hip prosthesis: Diagnostic and therapeutic strategies from a single institution experience

IntroductionGranuloma formation following total hip arthroplasty (THA) can occur regardless of the bearing surface. In very rare cases, extensive granulomas mimicking tumors may develop which are known as pseudotumors. The aim of this study is to report on these rare yet complex situations to stimulate reflection in diagnostic and therapeutic approaches. MethodsA retrospective case series study of 5 patients (2 females, 3 males) of aggressive granulomatous lesions on primary prostheses and 4 revision prostheses for aseptic loosening, implanted at a mean age of 74.8 years (range 64–83). A clinical, functional, radiographic, and anatomopathological analysis were conducted. ResultsFour patients underwent revision surgery, while one died before intervention. Functional impairment was significant with a mean pre-reintervention Postel-Merle d'Aubigné (PMA) score of 8.2 (range 4–11). Femoral involvement was constant, associated with acetabular involvement in only one case. bony involvement was major, with a minimum of 5 Gruen zones affected, showing complete cortical lysis. Histopathological analysis consistently revealed multinucleated giant cells and macrophages, predominantly with metallic wear particles. In 2 cases, vascular involvement was suspected without a clearly delineated tumor. Two cases required femoral resection prostheses, one necessitated inter-ilio-abdominal amputation due to extensive soft tissue involvement, one underwent implant removal which failed to prevent progression, and one patient died before reoperation. ConclusionThe volume of lesions in these 5 cases appears markedly larger than reported cases.Extensive pseudo-tumoral granulomatous lesions following THA are rare but carry poor functional prognosis. Evaluation to rule out infection and neoplastic pathology is imperative. Surgical management often resembling tumor treatment should be considered. Early diagnosis is crucial to allow intervention before reaching the stage of massive prosthetic replacement. Level of evidenceIV retrospective study.

Anatomical Reference of the Femur after Distal Resection Is Reliable for Rotational Alignment in Total Knee Arthroplasty.

The rotational alignment of the femoral component in total knee arthroplasty (TKA) is considered an important factor, but it is still difficult to assess intraoperatively. This study was conducted to identify anatomical parameters for femoral rotational alignment. A total of 204 patients who underwent primary TKA between 2015 and 2019 were enrolled. The femoral lateral (FLAP) and femoral medial anteroposterior (FMAP) lengths were measured as the widest lengths in the anteroposterior (AP) axis after distal femoral resection. The difference between FLAP and FMAP was defined as dFAP. The concordance correlation coefficient (CCC) was assessed for agreement between the cTEA-PCA and the value of femoral rotation using the linear regression analysis equation. HKA, FLAP, FMAP, and dFAP were significantly associated with femoral rotational alignment. The prediction equation combining the novel intraoperative anatomical references showed improved association with rotational alignment. If dFAP was 6.0 mm, the femoral rotation angle was calculated as 4.9° using this univariate regression equation. The CCC was 0.483, indicating moderate agreement. The dFAP showed an association with distal femoral rotational alignment. A 6 mm dFAP could be a reference for around 5° of femoral rotation. The equation developed in this study may be a reliable tool for intraoperative distal femoral rotational alignment.

The efficacy of physeal bar resection with guided growth in the treatment of physeal arrest with angular limb deformity

Premature physeal arrest can cause progressive deformities and functional disabilities of the lower limbs. This study addressed the outcomes after physeal bar resection with or without guided growth (temporary hemiepiphysiodesis) for the treatment of angular limb deformities. We retrospectively analyzed 27 patients (mean 9 years; range, 3–12 years) who underwent physeal bar resection of the distal femur (15 patients), proximal tibia (3 patients), and distal tibia (9 patients) between 2002 and 2020. Fifteen patients underwent physeal bar resection only (Group A), and the other twelve underwent simultaneous guided growth (Group B). The correction angle (angle change between the preoperative and last follow-up values) was compared and analyzed. The overall mean correction angle was 2.9° (range, − 9 to 18.3°). A total of 12 (45%) patients had a > 5° angular deformity improvement (mean, 9.6°; range, 5–18.3°), 9 (33%) had a < 5° angular change; and 6 (22%) had a > 5° worsening of the angular deformity (mean, 6.7°; range, 5.2–9°). The correction angle in Group B (mean 7.6° ± 6.2) was significantly higher than that in Group A (mean − 0.77° ± 6.3) (P = 0.01). We found six (40%) and zero patients with a > 5° angular deformity increase in Groups A and B, respectively (P < 0.047). The group that underwent physeal bar resection with guided growth showed significantly higher correction angles than the group that underwent physeal bar resection alone. Additionally, none of the patients in the guided growth group experienced an increased angular deformity. Therefore, combining guided growth with physeal bar resection may lead to better outcomes in the treatment of growth arrest with angular deformities.

Surgical factors play a critical role in predicting functional outcomes using machine learning in robotic-assisted total knee arthroplasty.

Predictive models help determine predictive factors necessary to improve functional outcomes after total knee arthroplasty (TKA). However, no study has assessed predictive models for functional outcomes after TKA based on the new concepts of personalised surgery and new technologies. This study aimed to develop and evaluate predictive modelling approaches to predict the achievement of minimal clinically important difference (MCID) in patient-reported outcome measures (PROMs) 1 year after TKA. Four hundred thirty robotic-assisted TKAs were analysed in this retrospective study. The mean age was 67.9 ± 7.9 years; the mean body mass index (BMI) was 32.0 ± 6.8 kg/m2. The following PROMs were collected preoperatively and 1-year postoperatively: knee injury and osteoarthritis outcome score for joint replacement, Western Ontario and McMaster Universities osteoarthritis index (WOMAC) Function, WOMAC Pain. Demographic data, preoperative CT scan, implant size, implant position on the robotic system and characteristics of the joint replacement procedure were selected as predictive variables. Four machine learning algorithms were trained to predict the MCID status at 1-year post-TKA for each PROM survey. 'No MCID' was chosen as the target. Models were evaluated by class discrimination (F1-score) and area under the receiver operating characteristic curve (ROC-AUC). The best-performing model was ridge logistic regression for WOMAC Function (area under the curve [AUC] = 0.80, F1 = 0.48, sensitivity = 0.79, specificity = 0.62). Variables most strongly contributing to not achieving MCID status were preoperative PROMs, high BMI and femoral resection depth (posterior and distal), supporting functional positioning principles. Conversely, variables contributing to a positive outcome (achieving MCID) were medial/lateral alignment of the tibial component, whether the procedure was an outpatient surgery and whether the patient received managed Medicare insurance. The most predictive variables included preoperative PROMs, BMI and surgical planning. The surgical predictive variables were valgus femoral alignment and femoral rotation, reflecting the benefits of personalised surgery. Including surgical variables in predictive models for functional outcomes after TKA should guide clinical and surgical decision-making for every patient. Level III.