Comparison of Novel 3D-printed Stepped Porous Metal Cones and Metaphyseal Sleeves for Reconstruction of Severe Knee Bone Defects: Short-term Clinical Outcomes.

OBJECTIVE: Both porous metal cones and metaphyseal sleeves are excellent implants for reconstructing severe bone defects in the knee joint, but they both exhibit design limitations. The porous metal cone, especially, has significant room for improvement in its shape design. The existing porous metal cones often feature a conical external surface with a relatively small taper, potentially compromising both rotational and axial stability. To improve both axial and rotational stability in porous metal cones, we developed a 3D-printed stepped porous metal cone. This study aimed to assess the short-term clinical outcome of the 3D-printed stepped porous metal cone and to compare it with the clinical outcome of patients who underwent revision total knee arthroplasty (rTKA) with the metaphyseal sleeves during the same period. METHOD: Patients who underwent total knee arthroplasty revision with metaphyseal bone defect reconstruction from 2019 to 2021 were retrospectively analyzed. A total of 61 patients were enrolled in the study, including 15 patients using 3D-printed stepped porous metal cones and 46 patients using metaphyseal metal sleeves. Thirty patients using metaphyseal sleeves were screened by propensity score matching method and compared with those using stepped cones. Analysis included the American Knee Society Score, the Hospital for Special Surgery knee score, the Western Ontario and McMaster Universities Arthritis index, the Short Form 12 (SF-12) health survey, and radiographic assessment with a mean follow-up of 28.5 ± 8.3 months. To conduct comparative analyses, unpaired Student's t-tests were employed for continuous variables, while categorical variables were analyzed using the appropriate Fisher exact or chi-squared test. RESULTS: In this study, the survival rates of both the stepped cone and metaphyseal sleeve were 100%. There was no statistically significant difference in postoperative knee function scores between the two groups (p > 0.05). However, patients in the cone group had significantly higher mental component summary scores on the SF-12 scale (p < 0.05) and higher increases in mean postoperative physical component summary scores than patients in the sleeve group (p < 0.05). In addition, patients in the cone group experienced fewer intraoperative and postoperative complications compared to the sleeve group. CONCLUSION: The 3D-printed stepped porous metal cone can effectively reconstruct bone defects in complex rTKA and provide satisfactory early clinical and radiographic results. The 3D-printed stepped cone provides a more stable structure similar to the sleeve while maintaining the original benefits of the cone making it a promising choice for rTKA.

Establishment and validation of an artificial intelligence web application for predicting postoperative in-hospital mortality in patients with hip fracture: a National cohort study of 52,707 cases.

BACKGROUND: In-hospital mortality following hip fractures is a significant concern, and accurate prediction of this outcome is crucial for appropriate clinical management. Nonetheless, there is a lack of effective prediction tools in clinical practice. By utilizing artificial intelligence and machine learning techniques, this study aims to develop a predictive model that can assist clinicians in identifying geriatric hip fracture patients at a higher risk of in-hospital mortality. METHODS: A total of 52,707 geriatric hip fracture patients treated with surgery from 90 hospitals were included in this study. The primary outcome was postoperative in-hospital mortality. The patients were randomly divided into two groups, with a ratio of 7:3. The majority of patients, assigned to the training cohort, were used to develop the AI models. The remaining patients, assigned to the validation cohort, were used to validate the models. Various machine learning algorithms, including logistic regression (LR), decision tree (DT), naïve Bayesian (NB), neural network (NN), eXGBoosting machine (eXGBM), and random forest (RF), were employed for model development. A comprehensive scoring system, incorporating 10 evaluation metrics, was developed to assess the prediction performance, with higher scores indicating superior predictive capability. Based on the best machine learning-based model, an AI application was developed on the Internet. In addition, a comparative testing of prediction performance between doctors and the AI application. FINDINGS: The eXGBM model exhibited the best prediction performance, with an AUC of 0.908 (95% CI: 0.881-0.932), as well as the highest accuracy (0.820), precision (0.817), specificity (0.814), and F1 score (0.822), and the lowest Brier score (0.120) and log loss (0.374). Additionally, the model showed favorable calibration, with a slope of 0.999 and an intercept of 0.028. According to the scoring system incorporating 10 evaluation metrics, the eXGBM model achieved the highest score (56), followed by the RF model (48) and NN model (41). The LR, DT, and NB models had total scores of 27, 30, and 13, respectively. The AI application has been deployed online at https://in-hospitaldeathinhipfracture-l9vhqo3l55fy8dkdvuskvu.streamlit.app/ , based on the eXGBM model. The comparative testing revealed that the AI application's predictive capabilities significantly outperformed those of the doctors in terms of AUC values (0.908 vs. 0.682, P <0.001). CONCLUSIONS: The eXGBM model demonstrates promising predictive performance in assessing the risk of postoperative in-hospital mortality among geriatric hip fracture patients. The developed AI model serves as a valuable tool to enhance clinical decision-making.

Cholestyramine alleviates bone and muscle loss in irritable bowel syndrome via regulating bile acid metabolism.

Irritable bowel syndrome (IBS) is a widespread gastrointestinal disorder known for its multifaceted pathogenesis and varied extraintestinal manifestations, yet its implications for bone and muscle health are underexplored. Recent studies suggest a link between IBS and musculoskeletal disorders, but a comprehensive understanding remains elusive, especially concerning the role of bile acids (BAs) in this context. This study aimed to elucidate the potential contribution of IBS to bone and muscle deterioration via alterations in gut microbiota and BA profiles, hypothesizing that cholestyramine could counteract these adverse effects. We employed a mouse model to characterize IBS and analysed its impact on bone and muscle health. Our results revealed that IBS promotes bone and muscle loss, accompanied by microbial dysbiosis and elevated BAs. Administering cholestyramine significantly mitigated these effects, highlighting its therapeutic potential. This research not only confirms the critical role of BAs and gut microbiota in IBS-associated bone and muscle loss but also demonstrates the efficacy of cholestyramine in ameliorating these conditions, thereby contributing significantly to the field's understanding and offering a promising avenue for treatment.

Metaphyseal Metal Sleeves for Reconstruction of Severe Knee Bone Defects: Excellent Survival Rate at a Mean Follow-Up of 6.4 Years.

OBJECTIVE: Management of bone loss in complex primary and revision total knee arthroplasty is key to the surgeries. Metaphyseal metal sleeves have been increasingly used recently to reconstruct severe knee metaphyseal bone defects. This study aimed to investigate the outcomes of the metaphyseal sleeve reconstructing Anderson Orthopedic Research Institute (AORI) type II and type III bone defects of knee joint. METHODS: From 2014 to 2019, a total of 44 knees were enrolled in this clinical retrospective study after the screening, including seven cases of primary TKA and 37 cases of revision TKA. The types of bone defects involved in this study were AORI types II and III, and did not involve AORI type I bone defects. Patients' knee function preoperatively and postoperatively as well as quality of life were recorded and analyzed. Analysis included the American Knee Society Score (KSS), hospital for special surgery knee score (HSS), the Western Ontario and McMaster Universities (WOMAC) index, the Short Form 12 (SF-12) health survey, visual analogue scale score, and radiographic assessment with a mean follow-up of 6.4 years. Paired t-tests were used to determine the significance of changes in clinical scores and knee mobility. RESULTS: A mean follow-up of 77.2 (±17.6, standard deviation [SD]) months was performed, and none of the patients underwent knee revision for infection or aseptic loosening. At the last follow-up, the KSS knee score changed statistically from 37.1 (±19.7) preoperatively to 86.5 (±13.6, SD, p < 0.001) postoperatively and the KSS function score from 32.7 (±24.0) preoperatively to 78.3 (±15.6, SD, p < 0.001) postoperatively. The knee mobility improved from a mean of preoperative 72.61° (±33.42°, SD) to 108.52° (±24.15°, SD, p < 0.001). Postoperative radiographs showed that the host bone was tightly integrated with the metaphyseal metal sleeve, and there was no obvious translucent line formation around the sleeve. Of the patients, 86.4% had a postoperative satisfaction score ≥8 (10-point scale). CONCLUSION: At the mean follow-up of 6.4 years, the survival rate of the metaphyseal sleeves was 100%. Metaphyseal sleeves combined with cementless stems is an excellent and viable option for reconstruction of AORI type II and type III bone defects of the knee.

The Influences of Cryopreservation Methods on RNA, Protein, Microstructure and Cell Viability of Skeletal Muscle Tissue.

Background: Different experiments require different sample storage methods. The commonly used preservation methods in biobank practice cannot fully meet the multifarious requirements of experimental techniques. Programmable controlled slow freezing (PCSF) can maintain the viability of tissue. In this study, we hypothesized that PCSF-preserved samples have potential advantages in matching subsequent experiments compared with existing methods. Methods: We compared the differences on skeletal muscle tissue RNA integrity, protein integrity, microstructure integrity, and cell viability between four existing cryopreservation methods: liquid nitrogen (LN2) snap-freezing, LN2-cooled isopentane snap-freezing, RNAlater®-based freezing, and PCSF. RNA integrity was evaluated using agarose gel electrophoresis and RNA integrity number. Freezing-related microstructural damage in the muscle tissue was evaluated using ice crystal diameter and muscle fiber cross-sectional area. Protein integrity was evaluated using immunofluorescence staining. Cell viability was evaluated using trypan blue staining after primary muscle cell isolation. Results: PCSF preserved RNA integrity better than LN2 and isopentane, with a statistically significant difference. RNAlater preserved RNA integrity best. PCSF best controlled ice crystal size in myofibers, with a significant difference compared with LN2. The PCSF method best preserved the integrity of protein epitopes according to the mean fluorescence intensity results, with a significant difference. Cell viability was best preserved in the PCSF method compared with the other three methods, with a significant difference. Conclusion: PCSF protected the RNA integrity, microstructural integrity, protein integrity, and cell viability of skeletal muscle tissue. The application of PCSF in biobank practice is recommended as a multi-experiment-compatible cryopreservation method.

Cementless Porous-Coated Metaphyseal Sleeves Used for Bone Defects in Revision Total Knee Arthroplasty: Short- to Mid-Term Outcomes.

OBJECTIVES: While many studies have presented excellent short-term outcomes of the metaphyseal sleeves used in revision total knee arthroplasty (TKA), currently published mid-term results remain limited and some controversial issues remain unresolved. The purpose of this study was to investigate clinical and radiographic mid-term outcomes of the sleeves for the management of metaphyseal bone defects in revision TKAs. METHODS: From 2015 to 2019, 44 patients (45 knees) who were operated with cementless porous-coated metaphyseal sleeve in revision TKA were included in this study. Bone defects were assessed according to Anderson Orthopaedic Research Institute Classification. On the tibial side, there were 37 type II and six type III, and with regards to the femur, 15 were type II, and four were type III. Through reviewing electronic records, data were collected, including baseline demographics, operative details, information of prothesis, and complications. Clinical and radiographic evaluations were performed, including Knee Society Scores (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), range of motion (ROM), the radiolucent line, level of joint line, and implant survival rate. Statistical analysis was performed by paired t-test for clinical and radiographic indexes. RESULTS: The mean follow-up time was 4.4 ± 1.4 years. During surgery, sleeve-related fractures were encountered in four (8.9%) knees, including incomplete tibial fracture of lateral cortex in one knee and of medial cortex in two knees, and longitudinal femoral metaphyseal fracture in one knee. Unions were achieved in all cases at the final follow-up. Significant improvements in KSS and WOMAC scores were found at the final follow-up, respectively, from 83.8 ± 29.1 to 152.9 ± 31.0 (t = -12.146, p < 0.001) and from 148.4 ± 42.3 to 88.1 ± 52.5 (t = 6.025, p < 0.001). The mean ROM improved from 88.7 ± 31.9° to 113.7 ± 13.7° (t = -5.370, p < 0.001). A 75 mm length of cementless stem was used in all patients and only one patient was identified as tibial end-of-stem pain. No sleeve-related revision occurred, and one patient was diagnosed with early postoperative infection and was treated with irrigation and debridement, polyethylene liner exchange, and appropriate antibiotic treatment. The overall implant survival was 97.8% with the endpoint reoperation and 100% with the endpoint revision. Osseointegration at the bone-sleeve interface was found in all patients and no loosening happened. Satisfactory alignment between 3° varus and 3° valgus was achieved in all but not in three patients. CONCLUSION: The use of metaphyseal sleeves in the treatment of bone defects in rTKAs can provide stable fixation and significantly improve the clinical scores at the midterm follow-up. In addition, the rare occurrence of end-of-stem pain suggests routine use of cementless stems. Although there are chances of intraoperative fractures, it has no negative effect on outcome when managed properly.

Early patellar tendon rupture after total knee arthroplasty: A direct repair method.

BACKGROUND: Patellar tendon rupture after total knee arthroplasty (TKA) is a catastrophic complication. Although the occurrence of this injury is rare, it can lead to significant dysfunction for the patient and is very tricky to deal with. There has been no standard treatment for early patella tendon rupture after TKA, and long-term follow-up data are lacking. AIM: To introduce a direct repair method for early patella tendon rupture following TKA and determine the clinical outcomes and complications of this method. METHODS: During the period of 2008 to 2021, 3265 consecutive TKAs were retrospectively reviewed. Twelve patients developed early patellar tendon rupture postoperatively and were treated by a direct repair method. Mean follow-up was 5.7 years. Demographic, operative, and clinical data were collected. The clinical outcomes were assessed using the Western Ontario and McMaster Universities (WOMAC) score, the Hospital for Special Surgery (HSS) score, knee range of motion, extensor lag, and surgical complications. Descriptive statistics and paired t test were employed to analyze the data. RESULTS: For all 12 patients who underwent direct repair for early patellar tendon rupture, 3 patients failed: One (8.3%) for infection and two (17.6%) for re-fracture. The two patients with re-fracture both underwent reoperation to reconstruct the extensor mechanism and the patient with infection underwent revision surgery. The range of motion was 109.2° ± 10.6° preoperatively to 87.9° ± 11° postoperatively, mean extensor lag was 21° at follow-up, and mean WOMAC and HSS scores were 65.8 ± 30.9 and 60.3 ± 21.7 points, respectively. CONCLUSION: This direct repair method of early patellar tendon rupture is not an ideal therapy. It is actually ineffective for the recovery of knee joint function in patients, and is still associated with severe knee extension lag and high complication rates. Compared with the outcomes of other repair methods mentioned in the literature, this direct repair method shows poor clinical outcomes.

Comparison of Preoperative Computed Tomography and Intraoperative Estimation in Predicting the Version of a Single-Wedge Femoral Stem.

OBJECTIVE: Early prediction of stem version aids in optimization of combined version during total hip arthroplasty (THA). This study aimed to analyze the discrepancy between stem version and native femoral version measured by different methods, and to explore which method can better predict the stem version. METHODS: We retrospectively reviewed 26 patients (39 hips) treated with robot-assisted THA in our hospital between September 2019 and December 2019. A straight, single-wedge, cementless stem (Accolade II) was used in all cases. Preoperative femoral version was measured at three levels on computerized tomography (CT) scan from the top to the middle level of femoral neck (Level 1 to Level 3). During THA, the version on cutting surface was measured prior to femoral broaching based on two reference lines: mid-cortical line and T line (trochanteric fossa to the middle of medial cortex). After femoral broaching, stem version was measured based on the femoral neck trial using Mako system (Stryker). In the statistical analysis, the difference and absolute discrepancy between stem version and femoral version measured with various methods were examined using paired t-test, and the relationship between stem version and various femoral versions were examined using correlation analysis. RESULTS: Mean femoral neck version (Level 1) was 9.5° ± 2.6° (range, -16.8°-42.5°), while mean stem version measured by Mako system was 19.9° ± 2.0° (range, -8.0°-49.0°). Femoral version measured with each method showed a moderate correlation with stem version (p < 0.05). There was a significant difference between stem version and femoral version except at Level 3, with a mean difference of 0.8° ± 13.6° (p = 0.729). With regard to the intraoperative estimation, stem version significantly increased compared to the value based on mid-cortical line, with a mean difference of 8.4° ± 13.1° (p < 0.001). However, the mean value of stem version was a little smaller than that of femoral version measured by reference to T line, but without statistical significance (p = 0.156). No postoperative dislocations occurred during the study period. No revision was required for any component. CONCLUSIONS: The middle level of femoral neck on CT scan and T line on cutting surface are better references to measure femoral version for predicting postoperative stem version. However, the relationship between stem version and predictive value was flexible. Therefore, further three-dimensional studies of postoperative CT are needed to validate the press-fit fixation and rotational freedom of the single-wedge stem.

Different squatting positions after total knee arthroplasty: A retrospective study.

BACKGROUND: Total knee arthroplasty (TKA) has been shown to improve quality of life and reduce pain. High-flexion activities such as squatting, kneeling, and floor transfers are mainly listed as demanding tasks. Among them, squatting is an important position. AIM: To provide a new squat position classification and evaluate the different squatting positions of a series of patients after primary TKA. METHODS: From May 2018 to October 2019, we retrospectively reviewed 154 video recordings of the squatting-related motions of patients after TKA. Among the included patients, 119 were women and 35 were men. Their mean age at the index surgery was 61.4 years (range, 30 to 77). RESULTS: The median follow-up was 12 mo (range, 6 to 156 mo). We classified those squatting-related motions into three major variations according to squatting depth: Half squat, parallel squat, and deep squat. The angles of hip flexion, knee flexion, and ankle dorsiflexion were measured in the screenshots captured from the videos at the moment of squatting nadir. A total of 26 patients were classified as half squats, 75 as parallel squats, and 53 as deep squats. The angles of hip flexion, knee flexion, and ankle dorsiflexion all differed significantly among the three squatting positions (P < 0.001). In the parallel squat group, the mean knee flexion angle (°) was 116.5 (SD, 8.1; range, 97 to 137). In the deep squat group, the mean knee flexion angle (°) was 132.5 (SD, 9.3; range, 116 to 158). CONCLUSION: Among the three squatting positions, deep squat showed the highest hip, knee, and ankle flexion angles, followed by the parallel squat. With the improvement of squatting ability, the patient's postoperative satisfaction rate was also significantly enhanced. However, the different squatting abilities of the patients cannot be effectively distinguished from the scoring results (P > 0.05). Our squatting position classification offers a pragmatic approach to evaluating patients' squatting ability after TKA.

The optimal screw-hole positions of the eccentric revision cup based on a morphological study.

BACKGROUND: Bridging bone defects in revision total hip arthroplasty is a challenge to orthopedic surgeons. The eccentric revision cup is a progression of jumbo cup. Our aim is to confirm the optimal screw-hole positions of the eccentric revision cup by morphological measurements of three-dimensional pelvic reconstruction. METHODS: Eighty CT images were converted to virtual three-dimensional bones. After simulating the surgery procedure, all available screw holes were inserted with the screws in virtual. By measuring the length of the screw in the pelvic bone, we determined the rich bone stock area. Then the screw holes were designed according to the characteristics of bone stock distribution. The peripheral screw-hole cluster and inner screw-hole cluster were studied respectively. RESULTS: For peripheral screw-hole cluster, five screw holes were evenly distributed between point A and point B in the thicker rim. For inner screw-hole cluster, screw hole 1 and screw hole 2 are the recommended inner screw holes. CONCLUSION: The eccentric revision cup has inherited the strengths of jumbo cup besides several unique advantages, including using the peripheral screws enhancing primary stability; decreasing the shift of hip rotation center and restoring biomechanical function; reducing the risk of dislocation because of the smaller head-cup differences; increasing the contact area between the outer cup and the host bone while maintaining a normal inclination of the inner cup. In this study, we confirmed the optimal screw-hole positions of the eccentric revision cup by surgical simulation and morphological measurement. However, biomechanical tests are still being further explored.

Change of Pelvic Sagittal Tilt after Total Hip Arthroplasty in Patients with Bilateral Crowe Type IV Developmental Dysplasia of the Hip.

OBJECTIVE: To explore and analyze the change of pelvic sagittal tilt (PST) after total hip arthroplasty (THA) in patients with bilateral Crowe type IV developmental dysplasia of the hip (DDH). METHODS: The study retrospectively evaluated 43 patients with bilateral Crowe type IV DDH undergoing THA from January 2008 to June 2019 who were followed up for 12 months postoperatively. Four parameters, including the ratio between the height and width of the obturator foramina(H/W ratio), the vertical distance between the upper edge of the symphysis and the middle of the sacrococcygeal joint (SSc distance), the vertical distance between the upper edge of the symphysis and the line connecting bilateral hip centers (SC distance) and the vertical distance between the upper edge of the symphysis and the line connecting the bilateral lower ends of the sacroiliac joints (SSi distance), which could indirectly reflect the change of PST, were observed and measured by radiographs. The change of each parameter before operation, immediately after operation, and in 3, 6 and 12 months postoperatively was compared and analyzed. RESULTS: Compared with the value before operation, the H/W ratio immediately after operation and in 3, 6 and 12 months postoperatively were 0.61 ± 0.12 (t = 0.893, P = 0.377), 0.61 ± 0.11 (t = 1.622, P = 0.112), 0.67 ± 0.10 (t = 5.995, P < 0.001) and 0.76 ± 0.12 (t = -9.313, P < 0.001), respectively, and the SSc, SC and SSi distance in 6 months postoperatively were 30.12 ± 7.06 mm (t = 3.506, P = 0.002), 42.8 ± 7.7 mm (t = 5.843, P < 0.001), 129.3 ± 12.6 mm (t = 5.888, P < 0.001), respectively, and in 12 months postoperatively were 27.24 ± 7.68 mm (t = 6.510, P < 0.001), 36.1 ± 9.1 mm (t = 9.230, P < 0.001), 118.9 ± 14.9 mm (t = 8.940, P < 0.001), respectively. The radiographs obtained in 6 and 12 months postoperatively demonstrated a significantly increased H/W ratio and decreased SSc, SC and SSi distance. At the last follow-up, the clinical evaluations significantly improved in all patients and there were no revisions. CONCLUSION: The significant change of pelvic sagittal posterior tilt in patients with bilateral Crowe type IV DDH might be a significant phenomenon after THA, which could occur in 6 months postoperatively.

Treatment of Osteoarthritis Secondary to Severe Coxa Vara with Modular Total Hip Arthroplasty.

OBJECTIVE: We aimed to demonstrate the methods of treatment for coxa vara with modular total hip arthroplasty (THA) and evaluate clinical and radiographic outcomes, and further survivorship at the midterm follow-up. METHODS: We retrospectively reviewed 33 patients (42 hips) who underwent modular THA for coxa vara deformity from May 2008 to December 2019. The clinical and radiographic results, including Harris Hip Score (HHS), leg length discrepancy (LLD), greater trochanteric height, femoral offset, abductor lever arm, stem alignment and limp, and complications, were evaluated. RESULTS: The follow-up time was mean 69.9±43.7 months. Clinically, the HHS improved significantly (p<0.001) on average from 42.90±14.44 points to 89.54±4.75 points. The mean LLD decreased from 33.3±19.4 mm to 5.0±5.8 mm (p<0.001), and 27 patients (82%) thought that total equality of the lower limbs was obtained. Patients demonstrated diminished or no limping in 88% (29/33) of hips and a significant improvement of biomechanics. At the final follow-up, all stems of hips were in clinical neutral alignment and the prostheses survivorship rates for all-causes revisions was 97.6%. CONCLUSION: Modular THA is a valuable alternative to render favorable outcomes for treatment of osteoarthritis secondary to severe coxa vara.

Factors influencing knee valgus alignment in Crowe type IV hip dysplasia after total hip arthroplasty.

BACKGROUND: Valgus deformity of the knee remains a complaint after total hip arthroplasty (THA) among some patients with Crowe type IV hip dysplasia. We aimed to identify the knee alignment in these patients before and after surgery, and to explore the factors contributing to postoperative knee valgus alignment. MATERIALS AND METHODS: We retrospectively reviewed a series of Crowe type IV patients who received THA between February 2010 and May 2019 in our hospital. The patients' medical data were collected from the hospital information system. On both preoperative and postoperative full limb length standing radiographs, the following parameters were measured: hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle, anatomical tibiofemoral angle, anatomical lateral distal femoral angle, femoral neck-shaft angle, pelvic obliquity, limb length, height and lateral distance of hip center, and femoral offset. Univariate and multivariate binary logistic regression were used to identify the factors influencing postoperative knee valgus alignment. RESULTS: A total of 64 Crowe type IV patients (87 hips) were included in the study. Overall, HKA improved from 176.54 ± 3.52° preoperatively to 179.45 ± 4.31° at the last follow-up. Those hips were subdivided into non-valgus group (≥ 177.0°, n = 65) and valgus group (< 177.0°, n = 22) according to postoperative HKA. Only postoperative mLDFA was a significant factor in the multivariate regression model. CONCLUSIONS: The postoperative mLDFA is a major factor related to knee valgus alignment after THA, which combines the preoperative anatomy and surgical reconstruction. Other factors previously published were found to have no significance. LEVEL OF EVIDENCE: III.

The Influence of Femoral Proximal Medullary Morphology on Subtrochanteric Osteotomy in Total Hip Arthroplasty for Unilateral High Dislocated Hips.

OBJECTIVE: To evaluate the predictive values of femoral proximal medullary morphology for the use of subtrochanteric osteotomy (STO) in unilateral Crowe IV developmental dysplasia of the hip (DDH). METHODS: Ninety four patients with unilateral Crowe type IV DDH (59 hips in STO group and 35 hips in the non-STO group) between April 2008 and June 2019 were enrolled. All patients underwent THA using the Pinnacle acetabular shell, ceramic liner and femoral head, the S-ROM stem with proximal sleeve. Three parameters on the standard anteroposterior hip radiographs were measured: the widths of medullary canals at 20 mm above the center of lesser trochanter (CLT)，20 mm below the CLT and the isthmus. Canal flare index (CFI), metaphyseal canal flare index (MCFI), diaphyseal canal flare index (DCFI) were calculated. A S-ROM femoral stem was used in all patients during total hip arthroplasty (THA). RESULTS: The CFI and DCFI in the STO group were lower than those in the non-STO group. However, there was no statistical difference in MCFI between the two groups. The receiver operating characteristic (ROC) curves shown that DCFI had the highest area under the curve (AUC), at 0.885. This was followed by the CFI, which had an AUC of 0.847. The AUC of MCFI was 0.579. The optimal threshold for DCFI was 1.44, which lead to a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 0.771, 0.898, 0.869, and 0.818, respectively. For CFI, the optimal threshold was 3.28, resulting in a sensitivity, specificity, PPV, and NPV of 0.829, 0.729, 0.878, and 0.644, respectively. CONCLUSIONS: The DCFI and CFI may be potent indicators in predicting the use of STO in unilateral Crowe IV DDH. The optimal threshold for CFI and DCFI were 3.28 and 1.44 and had good sensitivity and specificity for predicting the use of STO during THA.

False acetabulum is preoperative guidance for Crowe type IV hips on hip reduction without femoral shortening during total hip arthroplasty.

BACKGROUND: We aimed to analyze if the false acetabulum is a good indicator for determining femoral shortening. METHODS: We retrospectively included 102 patients with unilateral Crowe type IV developmental dysplasia who underwent primary total hip arthroplasty from April 2008 to May 2019. Based on the presence of false acetabulum, the 102 hips were further classified Crowe IVA group and Crowe IVB group. Radiographic measurement included the height of greater trochanter (HGT) preoperatively and postoperatively, which reflected the distalisation of greater trochanter (DGT). Harris hip score (HHS), limb length discrepancy (LLD), and complications were collected as clinical evaluation. RESULTS: Sixty hips were classified into Crowe IVA group, and 42 hips were classified into Crowe IVB group. Within Crowe IVA group, the proportion of hips treated with subtrochanteric osteotomy was significantly higher than that in Crowe IVB group (97% vs. 12%) (P < 0.001). The DGT in Crowe IVA group was also greater (67 vs. 32 mm) (P < 0.001). At last follow-up, both two groups obtained excellent clinical scores. There was no significant difference in postoperative LLD between the two groups (P = 0.001). Six dislocations occurred and three patients developed femoral nerve palsy, while all recovered in a year. CONCLUSION: The false acetabulum is a promising and good indicator for determining femoral shortening.

Jumbo cup in hip joint renovation may cause the center of rotation to increase.

BACKGROUND: Utilizing the large jumbo cup in revision total hip arthroplasty is an effective approach to cure many lacunar and segmental peripheral bone defects. However, with the use of the jumbo cup, the center of the hip joint may become elevated relative to the primary acetabulum, and the diameter of the large cup is greater. AIM: To study the height and the significance of the elevation of the hip joint center. METHODS: Eighty-eight patients matched the criteria for this condition and were included in the study. The center height of the hip joint was measured relative to the opposite normal hip joint. The diameter of the jumbo cup was measured and checked according to operation notes, and the diameter of the jumbo cup was measured with a prosthesis label. Then, the horizontal and vertical centers of rotation were measured on the surgical side and opposite side. The average center height of the hip joint on the renovated side and the opposite side and the position of the hip cup relative to the teardrop were compared using a paired t-test. RESULTS: Radiometric analysis showed that the average hip joint center was elevated by 7.6 mm. The rotational center height delta of the renovated hip was 7.6 ± 5.6 mm, and there was an obvious difference between the two groups (P = 0.00). The difference in horizontal distance was 0.5 ± 5.1 mm (-11.5 -14.0 mm), and there was no obvious difference between the two groups (P = 0.38). According to the foreign standard, the rotational center height delta of the renovated hip was 7.5 ± 6.2 mm, and there was a significant difference between the two groups (P = 0.00). There was no obvious difference between the domestic and foreign standards (P > 0.05) between the two groups. CONCLUSION: The application of the jumbo cup elevates the rotational center of the hip joint, but it is feasible and effective to use the jumbo cup.

Changes in Distribution of Lower Limb Alignment After Total Hip Arthroplasty for Crowe IV Developmental Dysplasia of the Hip.

PURPOSE: The purpose of this study was to evaluate the distribution of lower limb alignment in Crowe IV developmental dysplasia of the hip (DDH) before and after total hip arthroplasty (THA). PATIENTS AND METHODS: We retrospectively included 64 Crowe IV DDH patients (87 hips) who underwent THA between February 2010 and May 2019. Radiographic parameters were measured on full limb length standing anteroposterior radiographs, including hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), anatomical lateral distal femoral angle (aLDFA), and anatomical tibiofemoral angle (aTFA). RESULTS: HKA improved from 176.54°±3.52° preoperatively to 179.45°±4.31° at the last followup (P<0.001). According to the preoperative HKA, 40 hips were defined as knee valgus alignment. The majority of them were characteristic of a valgus mLDFA and a valgus or neutral mMPTA (35%, 47.5%). After THA, there were still 22 hips defined as knee valgus alignment. More than 50% of them were characteristic of a valgus mLDFA and a neutral mMPTA. Five hips (22.7%) revealed valgus alignment in both mLDFA and mMPTA. Twenty-one hips (24.1%) remained knee valgus alignment before and after surgery. One hip, defined as neutral alignment, preoperatively turned into valgus alignment after surgery. CONCLUSION: Both preoperative and postoperative sources of valgus alignment were mainly from the femoral side among Crowe IV DDH patients. THA mainly played a positive role in the reconstruction of lower limb alignment in these patients.

[Status and treatment of knee extension device disruption after total knee arthroplasty].

OBJECTIVE: To summarize the principle, classification, and treatment methods of knee extension device disruption after total knee arthroplasty (TKA). METHODS: By extensively consulted the relevant domestic and abroad literature, the principle, classification, and treatment methods of injury according to different parts of the knee extension device after TKA were summarized and analyzed. RESULTS: The knee extension device disruption after TKA mainly occurs in the quadriceps tendon, patella tendon, and patella. Once the knee extension device is injured, it will seriously affect the functional recovery of the patient after surgery, resulting in delayed knee extension, limited range of motion, difficulty walking, and joint pain, etc. The current treatment methods are diverse, including conservative treatment and surgical treatment. Surgical treatment includes direct suture repair (traditional perosseous fixation and suture anchoring techniques), reconstruction and reinforcement repair (reconstruction using synthetic patches, autografts, and allografts). For the treatment of different parts, it is necessary to comprehensively consider the patient's knee joint tissue condition, the presence or absence of underlying diseases, and the presence or absence of donors. CONCLUSION: There is no uniform conclusion on the treatment of knee extension device disruption after TKA. Different injury situations need to be considered comprehensively to choose the appropriate treatment method.

Functional and radiographical results of asymmetrically reconstructed total hip arthroplasty in patients with bilateral dysplastic arthritic hips with one hip Crowe II-III and the other Crowe IV: a retrospective cohort study.

BACKGROUND: The study aimed to evaluate the functional and radiographical results of asymmetrically reconstructed total hip arthroplasty in patients with bilateral dysplastic arthritic hips with one hip Crowe II-III and the other hip Crowe IV. MATERIALS AND METHODS: From April 2006 to April 2019, we evaluated 23 patients who had a reconstruction of one Crowe II-III hip with high hip center (HHC) and the other Crowe IV hip at the anatomical position (H group). The radiographic and clinical outcomes were compared with those of a control group of 19 patients with bilateral dysplasia who had one Crowe IV hip and the contralateral hip both reconstructed in the anatomical position (A group). Medical records and radiographs were reviewed, and a complete follow-up was conducted for all patients. RESULTS: The mean vertical center of rotation (V-COR) and horizontal center of rotation (H-COR) in the H group were 30.6 ± 5.8 mm and 30.0 ± 5.5 mm, respectively. In the A group, the corresponding values were 14.0 ± 4.3 mm and 23.0 ± 2.3 mm, respectively. A significant difference was found in terms of V-COR and H-COR between the two groups, and no significant difference was shown regarding the cup inclination, abductor lever arm (ALA), ALA ratio, and leg length discrepancy (LLD). Three patients of the H group and four patients of the A group exhibited LLD > 10 mm. All seven patients who had LLD > 10 mm underwent the shortening subtrochanteric osteotomy (SSTO) of the Crowe IV hip. Subgroup analysis based on the presence and absence of SSTO showed that the LLD of the SSTO group was greater than that of the non-SSTO group in both groups, but the difference was only statistically significant in the A group. At the last follow-up, the mean Harris Hip Scores significantly improved in the two groups, and there was no revision during the follow-up period. In the H group, four patients presented with a slight limp and three patients with a moderate limp, while it was six patients and one patient in the A group, respectively. CONCLUSIONS: Asymmetrical reconstruction in patients with bilateral dysplastic arthritic hips with one hip Crowe II-III and the other Crowe IV is acceptable and comparable when compared with bilateral anatomical reconstruction. LEVEL OF EVIDENCE: III, retrospective observational study. Trial registration Chinese Clinical Trail Registry. ChiCTR2000033848.

The Variation of the Pelvis in Unilateral Crowe Type IV Developmental Dysplasia of the Hip.

OBJECTIVE: To investigate variation of the pelvis in unilateral Crowe type IV developmental dysplasia of the hip (DDH) and analyze the reliability of pelvic landmarks. METHODS: We retrospectively received preoperative anteroposterior pelvic radiographs for 89 adult patients with unilateral Crowe type IV DDH at our institution between September 2008 and May 2019. Forty-eight patients without a false acetabulum was type IVA and 41 with a false acetabulum was type IVB. The heights of the ilium, acetabulum, and ischium areas in affected and unaffected sides were measured. The ratios of the three areas in entire pelvis are calculated. The discrepancies of bilateral iliac crest, inferior sacroiliac articulation, teardrop, and ischial tuberosity on the bisector of the pelvis were also measured. RESULTS: The mean heights of the ilium, acetabulum, ischium areas in the affected side were 74.4, 88.6, and 37.0 mm, respectively, in type IVA group and 77.7, 83.5, and 37.8 mm, respectively, in type IVB group. The heights in the unaffected side were 82.1, 84.6, and 43.8 mm, respectively, in type IVA group and 84.6, 82.0, and 44.0 mm, respectively, in type IVB group. The ratios of the ilium, acetabulum, ischium areas in affected side of Crowe type IVA group were 0.37, 0.44, and 0.19, respectively, and the ratios in unaffected side were 0.39, 0.40, and 0.21, respectively. The ratios in affected side of Crowe type IVB group were 0.39, 0.42, and 0.19, respectively, and the ratios in unaffected side were 0.40, 0.39, and 0.21, respectively. The discrepancies of bilateral iliac crest, inferior sacroiliac articulation, teardrop, and ischial tuberosity on the line of the bisector of the pelvis in Crowe type IVA group were 5.6, 5.2, 2.0, and 7.1 mm, respectively. Those in Crowe type IVB group were 8.1, 3.5, 3.5, and 4.9 mm, respectively. CONCLUSIONS: Pelvic asymmetry was a common occurrence in unilateral Crowe type IV DDH in adults. Furthermore, it should be reliable to use teardrop as pelvic landmark to balance leg length discrepancy in preoperative planning.