Comparison of Functional and Radiographic Outcomes Between Two Fixation Methods for Extended Trochanteric Osteotomy in Revision Total Hip Arthroplasty: A Retrospective Cohort Study.

BACKGROUND: To compare the functional and radiographic outcomes between two fixation methods for extended trochanteric osteotomy (ETO) in revision total hip arthroplasty (rTHA). METHODS: Included in this study were 64 patients who underwent ETO in rTHA using either claw-plate fixation (claw-plate group, n = 31) or cable-alone fixation (cable group, n = 33) in our hospital from 2008 to 2020. The functional and radiographic results and complications were compared between the groups during a mean follow-up period of 64 and 78 months. RESULTS: The Harris hip score and visual analogue scale at the last follow-up improved significantly in both groups, showing no significant statistical difference between the two fixation methods. In the cable group, the mean abductor lever arm, the proximal migration, and medial migration in the affected hip were significantly decreased compared to those in the contralateral normal hip (P < .05), whereas in the claw-plate group no significant statistical differences were observed between two sides. No or slight limping occurred in 25 patients (81%) in the claw-plate group and 16 patients (48%) in the cable group (P = .007). A multiple logistic regression demonstrated that claw-plate fixation could reduce the incidence of postoperative moderate-to-severe limping. CONCLUSION: Both claw-plate fixation and cable-alone fixation could improve the functional performance of rTHA with ETO, whereas claw-plate fixation could offer superior biomechanical results and gait improvement as compared with cable-alone fixation.

The application of custom-made 3D-printed titanium augments designed through surgical simulation for severe bone defects in complex revision total hip arthroplasty.

BACKGROUND: With the development of radiology and three-dimensional (3D) printing technology, custom-made 3D-printed titanium augments have been more widely used. However, the radiological and clinical outcomes of custom-made augments lack reports. To better understand the clinical effect of using 3D-printed titanium augments and the significance of accurate placement, the aim of this study was to assess the outcomes when using custom-made 3D-printed titanium augments and to validate the idea that surgical simulation should be done before designing custom-made augments. METHODS: A retrospective review was conducted on 31 surgical simulations and revision total hip arthroplasties using custom-made 3D-printed titanium augments. The safe zone, cup position, and hip rotation center were measured on anteroposterior radiographs. Clinical outcomes were assessed with a mean 21.1 months of follow-up. RESULTS: All patients were positioned within the safe zone, and none of the acetabular cups nor the custom-made augments had any evidence of migration at the latest follow-up. A strong correlation was found between the planned cup position and the postoperative position. The average vertical position of the center of rotation was significantly increased from 3.55 cm to 2.35 cm. The mean Harris Hip Score was increased from 40.81 preoperatively to 65.46 postoperatively. Complications included gait abnormality, groin pain, fracture of the greater trochanter, and partial palsy of the sciatic nerve. However, patient satisfaction reached 92.3%. CONCLUSION: Surgical simulations help to design custom-made augments accurately and improve surgical plans. Acetabular components supported with custom-made 3D-printed augments is a useful method to bridge severe bone deficiencies. In this study, both the radiologic results and clinical outcomes were favorable. LEVEL OF EVIDENCE: Level 4.

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.

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.

Model to Predict Need for Subtrochanteric Shortening Osteotomy During Total Hip Arthroplasty for Crowe Type IV Developmental Dysplasia.

BACKGROUND Indications for subtrochanteric shortening osteotomy (SSOT) during Crowe type IV developmental dysplasia of the hip (DDH) are unclear. The aim of this retrospective study was to create a model to predict the need for performing SSOT. MATERIAL AND METHODS One hundred forty-nine patients (186 hips) with Crowe Type IV DDH who underwent total hip arthroplasty (THA) with S-ROM implants from January 2010 to November 2018 were included in the study. The acetabular components were placed at the true acetabulum and the trial femoral component was inserted. Reduction then was attempted and if it could not be achieved, SSOT was performed. Using multivariable Cox regression analysis, a model was constructed that included age, sex, surgical history, use of a cone- or triangle-shaped sleeve, secondary acetabulum formation, and percentage of dislocation as predictive factors for SSOT. RESULTS SSOTs were performed on 140 of 186 hips. Secondary acetabulum formation was present in 27 hips (58.70%) in which SSOT was not performed 7 (5.00%) in which it was performed. Cone-shaped sleeves were used in 17 hips (36.96%) in which SSOT was not performed versus 15 (10.71%) hips in which it was performed. Dislocation occurred in 31.30±5.80% hips in which SSOT was performed versus 24.05±4.39% of those in which it was not performed. Percentage of dislocation was associated with an increased likelihood of SSOT (odds ratio [OR] 1.24, 95% confidence interval 1.11-1.38), whereas secondary acetabulum formation (OR 0.10, 0.03-0.33) and use of a cone-shaped sleeve (0.18, 0.06-0.53) were associated with decreased likelihood of SSOT. We established a model for prediction of SSOT with a nanogram and the discriminative ability (C statistic) of it was 0.918 (0.79-0.92). CONCLUSIONS Factors that significantly affect likelihood of performing an SSOT were identified and a model with significant ability to predict the need for SSOT in patients with Crowe Type IV DDH was created.

Comparison between the Staphylococci aureus and coagulase-negative staphylococci infected total joint arthroplasty treated by two-stage revision: A retrospective study with two year minimum follow-up.

BACKGROUND: Staphylococcus species are major pathogens of peri-prosthetic joint infection (PJI). Coagulase-positive staphylococci and coagulase-negative staphylococci have different intrinsic virulences. However, few studies have specifically compared the clinical manifestations and two-stage revision outcomes of PJI caused by these two species. METHODS: We retrospectively collected 260 arthroplasty patients who underwent a two-stage revision because of PJI from January 2003 to June 2015 in our institute because of PJI. Sixty-four patients (36 hips and 28 knees) and 23 patients (13 hips and 10 knees) were infected by coagulase-negative staphylococci (CoNS) and SA, respectively. RESULTS: The preoperative mean ESR value of the SA group was higher than that of the CoNS group (median, 60.9 VS 35.9; P < 0.001). Seventeen (73.9%) of the 23 SA infected patients had a sinus tract, while only 12 (18.8%) of the 64 CoNS-infected patients had this symptom (73.9% VS 18.8%; P < 0.001). At the time of follow-up, 58 (90.6%) of the 64 CoNS-infected patients had successfully controlled the infection. In the SA group, 20 (87.0%) patients ultimately acquired successful control (90.6% VS 87.0%; P = 0.923). Surgical history was identified as a potential risk factor (OR = 6.2, 95%CI 1.17-32.4) for prognosis when potential covariates were adjusted. CONCLUSIONS: SA infection has a higher ESR value and a more frequent occurrence of sinus tract. The infection control rate of the two-stage revision protocol was close to 90% for both SA and CoNS species, and there is no statistically significant difference in the eradication rate of infection between the SA and CoNS groups. Surgical history may be a good predictor of failure for PJI patients treated with two-stage revision.

Success Rate of Fungal Peri-Prosthetic Joint Infection Treated by 2-Stage Revision and Potential Risk Factors of Treatment Failure: A Retrospective Study.

BACKGROUND The aim of this study was to investigate the success rate of fungal peri-prosthetic joint infection treated by 2-stage revision and related factors of treatment failure to offer a better treatment protocol. MATERIAL AND METHODS We reviewed 18 joints (13 knees and 5 hips) of 17 patients (10 women and 7 men) diagnosed with fungal peri-prosthetic joint infection from January 2000 to June 2015 at our institute. The mean follow-up was 65.1 months (range, 25-129 months). All joints were treated with complete debridement, implantation of antifungal-loaded cement spacers, at least 6 weeks of parenteral antifungal agents, and delayed reimplantation. RESULTS Notably, 15 joints were infected with Candida, and molds were isolated in 3 joints. The median duration of resection arthroplasty and reimplantation was 33.9 weeks (range, 12-132 weeks). Thirteen (10 knees and 3 hips, 72.2%) of the 18 joints (13 knees and 5 hips) had no recurrent or persistent infection, while the remaining 5 joints (3 knees and 2 hips, 27.8%) failed to control infection after reimplantation of prosthesis or spacer. The long interval between prosthesis resection and reimplantation (69 weeks vs. 23.1 weeks, p=0.240) and mixed bacterial infection (80% vs. 46.2%, p=0.314) were associated with higher failure rate. CONCLUSIONS Debridement with the retention of the prosthesis is not an ideal treatment protocol for fungal peri-prosthetic joint infection; thus, a two-stage revision could be valid. We suggest that 6 weeks of parenteral antifungal agents are necessary, and 6 subsequent weeks of oral antifungal treatment is also important. We do not recommend that the two-stage revision be performed on patients who have more than 2 host risk factors.

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.

[Value of personalized extramedullary positioning technique on tibia side for coronal alignment of tibial prosthesis in total knee arthroplasty].

OBJECTIVE: To explore the coronal alignment of tibial prosthesis after osteotomy using personalized extramedullary positioning technique on tibia side in total knee arthroplasty (TKA). METHODS: A clinical data of 170 patients (210 knees) who underwent primary TKA between January 2020 and June 2021 and met the selection criteria was retrospectively analyzed. Personalized and traditional extramedullary positioning techniques were used in 93 cases (114 knees, personalized positioning group) and 77 cases (96 knees, traditional positioning group), respectively. The personalized extramedullary positioning was based on the anatomical characteristics of the tibia, a personalized positioning point was selected as the proximal extramedullary positioning point on the articular surface of the tibial plateau. There was no significant difference between the two groups in gender, age, body mass index, surgical side, course of osteoarthritis, and Kellgren-Lawrence classification ( P>0.05). The preoperative tibial bowing angle (TBA) formed by the proximal and distal tibial coronal anatomical axes in the personalized positioning group was measured and the tibia axis was classified, and the distribution of personalized positioning point was analyzed. The pre- and post-operative hip-knee-ankle angle (HKA), the lateral distal tibial angle (LDTA), and the postoperative tibia component angle (TCA), the excellent rate of tibial prosthesis alignment in coronal position were compared between the two groups. RESULTS: In the personalized positioning group, 58 knees (50.88%) were straight tibia, 35 knees (30.70%) were medial bowing tibia, and 21 knees (18.42%) were lateral bowing tibia. The most positioning points located on the highest point of the lateral intercondylar spine (62.07%) in the straight tibia group, while in the medial bowing tibia and lateral bowing tibia groups, most positioning points located in the area between the medial and lateral intercondylar spines (51.43%) and the lateral slope of the lateral intercondylar spine (57.14%), respectively. The difference in HKA between pre- and post-operation in the two groups was significant ( P<0.05); while the difference in LDTA was not significant ( P>0.05). There was no significant difference in preoperative LDTA and HKA and the difference between pre- and post-operation between groups ( P>0.05). But there was significant difference in postoperative TCA between groups ( P<0.05). The postoperative tibial plateau prosthesis in the traditional positioning group was more prone to varus than the personalized positioning group. The excellent rates of tibial prosthesis alignment in coronal position were 96.5% (110/114) and 87.5% (84/96) in personalized positioning group and traditional positioning group, respectively, showing a significant difference between groups ( χ 2=7.652, P=0.006). CONCLUSION: It is feasible to use personalized extramedullary positioning technique for coronal osteotomy on the tibia side in TKA. Compared with the traditional extramedullary positioning technique, the personalized extramedullary positioning technique has a higher excellent rate of tibial prosthesis alignment in coronal position.

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.

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.

[Clinical effect of Corail femoral prosthesis with different offset in total hip arthroplasty].

OBJECTIVE: To explore the early clinical efficacy of primary total hip arthroplasty(THA) with Corail standard stems (KS type) and high offset stems (KHO type), by analyzing the postoperative radiographic parameters of different offset of femoral components with Corail stem which has a neck-shaft angle of 135 ° in unilateral primary THA, by comparing the measurement results on both sides and analyzing the reconstruction of the postoperative femoral offset and the hip joint function recovery. METHODS: A retrospective analysis was made of 186 patients with unilateral hip joint lesions who underwent the first total hip arthroplasty with Johnson & Johnson Corail prostheses from January 2015 to June 2017. According to the use of femoral prostheses with different eccentricities during the operation, the patients were divided into high eccentricity group and standard eccentricity group. In the high eccentricity group, there were 52 cases of Corail high eccentricity prosthesis(KHO type), including 20 females and 32 males;aged 21 to 71 years old with an average of(50.6±13.2) years;body mass index(BMI) was (26.0±4.1) kg/m2. The standard eccentricity group included 134 Corail standard femoral stem prostheses(KS type), 57 females and 77 males;aged 18 to 77 years old with an average of (47.3±14.0) years;BMI was (25.3±3.5) kg/m2. The abduction arm, femoral eccentricity, acetabular eccentricity and the length difference of lower limbs were measured on the postoperatively positive X-ray film of the hip joint. Harris score and related complications were recorded before and after the operation, and the stability of the prosthesis was analyzed. RESULTS: There were significant differences in femoral eccentricity, joint eccentricity and abduction arm between the affected side and the healthy side in the high eccentricity group(P<0.05). There were significant differences in femoral eccentricity and acetabular eccentricity between the affected side and the healthy side in the standard eccentricity group(P<0.05). There were significant differences in combined eccentricity, abduction arm and length of lower limbs between two groups(P<0.05). In the high eccentricity group, the abduction arm of the affected hip joint was positively correlated with the femoral eccentricity, acetabular eccentricity and joint eccentricity(r=0.633, P<0.001;r=0.384, P=0.005;r=0.690, P<0.001). The same results were also obtained in the healthy side(r=0.688, P<0.001;r=0.574, P<0.001;r=0.765, P<0.001). In the standard eccentricity group, the abduction arm of the affected hip joint was positively correlated with the femoral eccentricity, acetabular eccentricity and combined eccentricity(r=0.734, P<0.001;r=0.418, P<0.001;r=0.749, P<0.001). The same results were also obtained in the healthy side(r=0.775, P<0.001;r=0.397, P<0.001;r=0.773, P<0.001). The difference of the length of both lower limbs was significantly correlated with the difference of bilateral joint eccentricity and bilateral abduction arm (r=0.376, P=0.006;r=-0.346, P=0.012). There was no significant correlation between the difference of the length of both lower limbs and the difference of bilateral joint eccentricity and bilateral abduction arm (r=-0.009, P=0.919;r=-0.036, P=0.682). There was no significant difference in Harris score between two groups at the last follow-up(P>0.05). At the last follow-up, Trendelenburg was negative in all patients in both groups, and the prostheses were stable. CONCLUSION: Both Corail standard stem and high offset stem may be effectively reconstruct the femoral offset, reconstruct the anatomical structure and biomechanics of the hip joint, and maintain the length of lower limbs and the stability of the hip joint in the unilateral primary total hip arthroplasty. Although the offset of the femur was not reconstructed normally in some cases, the stability of the components and postoperative function were not affected.

Performance characteristics of 18F-fluorodeoxyglucose in non-infected hip replacement.

Purpose: The aim of this study was to retrospectively analyze 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/ computed tomography (CT) images of non-infected hip arthroplasty patients and summarize findings that may be useful for clinical practice. Methods: 18F-FDG PET/CT images of non-infected hip arthroplasty patients were collected from September 2009 to August 2021. The region of interest was independently delineated by two physicians and maximum standardized uptake values (SUVmax) were recorded and compared. Serologic data were also collected and the correlation between SUVmax and serologic parameters was analyzed, while the images were classified based on the 18F-FDG uptake pattern in the images using the diagnostic criteria proposed by Reinartz et al. (9). The interval between hip replacement and PET/CT was classified by year and the characteristics of the two groups were compared. The images of patients who underwent PET/CT multiple times were analyzed dynamically. Results: A total of 121 examinations were included; six patients underwent PET/CT twice and two patients had three scans. There were no significant correlations between SUVmax and serologic results. The interobserver agreement between the two physicians in the classification according to the criteria of Reinartz et al. (9) was 0.957 (P < 0.005). Although there was non-specific uptake in cases with an arthroplasty-to-PET/CT interval this was non-significant. Additionally, 18F-FDG showed potential utility for dynamic observation of the condition of the hip. Conclusion: SUVmax provided information independent of serologic results, meanwhile 18F-FDG showed potential applicability to the dynamic monitoring of hip arthroplasty-related diseases. However, the presence of blood vessels and muscles affected image interpretation and the specificity of 18F-FDG was not optimal. A more specific radionuclide is needed to maximize the benefits of using PET/CT for the assessment of periprosthetic joint infection (PJI).

[Application of high offset Corail femoral stem prosthesis in unilateral primary total hip arthroplasty].

OBJECTIVE: To investigate the application of high offset femoral stem prosthesis in primary total hip arthroplasty. METHODS: From January 2015 to June 2017, 51 patients with unilateral hip diseases who underwent primary total hip arthroplasty with Corail high offset femoral stem prosthesis(KHO type) were selected for retrospective study, including 20 females and 31 males;the age ranged from 21 to 71 years old with an average of(50.8±13.3) years old. The abduction arm, femoral offset, acetabular offset and the length of lower limbs were measured on the positive X-ray film of hip joint after operation. Harris scores before and after operation and related complications were recorded, and the stability of prosthesis was analyzed. RESULTS: The femoral offset, combined offset and abduction arm of the affected side were significantly greater than those of the healthy side(P<0.05). There was no significant difference in acetabular offset between the affected side and the healthy side (P>0.05). The femoral offset of 17 hips (33.3%) was reconstructed normally, of which 15 cases (88.2%) had equal length of both lower limbs. The femoral offset of 34 hips (66.7%) was greater than that of the healthy side, and 34 cases (100%) had equal length of both lower limbs. All 51 patients were followed up for(42.3±7.3) months. The Harris score increased from 38.0±7.6 before operation to 92.1±3.1 at the final follow-up(P<0.001). CONCLUSION: Although the high offset Corail prosthesis can not normally reconstruct the femoral offset in unilateral primary total hip arthroplasty, it does not affect the reconstruction of the length of lower limbs and the stability of the prosthesis.

[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.

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.

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 Affecting Squatting Ability in Total Knee Arthroplasty Using High Flexion Prosthesis.

PURPOSE: Total knee arthroplasty (TKA) is widely used as a treatment for knee osteoarthritis. Few studies have analysed the factors affecting the squatting ability of patients after TKA. The purpose of this study was to comprehensively analyse the factors affecting squatting ability after TKA and to determine which ones are important. PATIENTS AND METHODS: Three hundred primary TKA cases with a minimum 3-year follow-up were retrospectively analysed. All patients received a conventional posterior-stabilized TKA implant and underwent a standard perioperative care pathway. The patients were divided into two groups according to the squatting position and knee flexion angle while weight-bearing (Group I - inability to squat group, Group II - ability to squat group). Demographic, operative, and clinical data were collected. Radiographic assessment included joint line elevation, patellar position, posterior condylar offset (PCO), etc. Statistical analysis of the effect of all the above factors on squatting ability was performed. RESULTS: The preoperative range of motion and joint line of Group I were 82.9±12.6 and 3.24±1.07, respectively, and those of Group II were 107±9.6 and 1.83±0.89 respectively. The univariate analysis showed that age, prosthesis size, preoperative ROM and joint line position were correlated with squatting ability. But in the final multivariate analysis, joint line position and preoperative ROM were independent influencing factors that affected squatting ability after TKA (p value < 0.01). CONCLUSION: Preoperative ROM and joint line position were independent influencing factors affecting squatting ability after TKA. Patients should be counseled accordingly and be made to understand these factors. To ensure that patients can squat postoperatively, we should improve surgical techniques to control joint line elevation.

[Prevention and treatment of iatrogenic medial collateral ligament injuries in total knee arthroplasty].

OBJECTIVE: To summarize the prevention and treatment of iatrogenic medial collateral ligament (MCL) injuries in total knee arthroplasty (TKA). METHODS: The relevant literature about iatrogenic MCL injuries in TKA was summarized, and the symptoms, causes, preventions, and treatments were analyzed. RESULTS: Preventions on the iatrogenic MCL injuries in TKA is significantly promoted. With the occurrence of MCL injuries, the femoral avulsion can be fixed with the screw and washer or the suture anchors; the tibial avulsion can be treated with the suture anchors fixation, bone staples fixation, or conservative treatment; the mid-substance laceration can be repaired directly; the autologous quadriceps tendon, semitendinosus tendon, or artificial ligament can be used for the patients with poor tissue conditions or obvious residual gap between the ligament ends; the use of implant with greater constraint can be the last alternative method. CONCLUSION: No consensus has been reached to the management of iatrogenic MCL injuries in TKA. Different solutions and strategies can be integrated and adopted flexibly by surgeons according to the specific situation.