Preoperative valgus-corrected hip-knee-ankle angle and medial meniscal extrusion are useful for evaluating postoperative alignment in mobile-bearing UKA.

Purpose: The purposes of the study were to analyze the correlation between preoperative variables (valgus corrected hip-knee-ankle angle (vcHKA), medial osteophyte areas of the tibia and femur, and medial meniscus extrusion (MME)) and the postoperative alignment in mobile-bearing unicompartmental knee arthroplasty (UKA). Methods: This study enrolled 109 patients (118 knees) who underwent mobile-bearing UKA between January 1, 2019 and January 1, 2023, retrospectively. Radiographic parameters, including the HKA, hip-knee-shaft angle (HKS), and valgus-corrected femorotibial angle (vcFTA), were measured using preoperative radiographs. The vcHKA was calculated as vcFTA - HKS. The medial osteophyte areas of the tibia and femur and MME were measured using knee magnetic resonance imaging (MRI). Simple and multiple linear regression analyses, univariate and multivariate logistic regression analyses, and receiver operating characteristic (ROC) curves were performed. Results: In total, 109 patients (118 knees) were enrolled in this study. In the multiple linear regression analysis, vcHKA (ß = 0.732, 95 % confidence interval (95%CI) = 0.582 to 0.881; p < 0.001) and MME (ß = 0.203, 95%CI = 0.001 to 0.405; p = 0.049) were positively correlated with postoperative HKA, and postoperative HKA was modeled according to the following equation: 45.420 + (0.732° * vcHKA) + (0.203 mm × MME). In the multivariate logistic regression analysis, vcHKA (odds ratio (OR) = 2.007, 95 % CI = 1.433 to 2.810, p < 0.001) was associated with postoperative valgus malalignment independently. In the ROC curve, vcHKA (cutoff value: 180°) was predictive of postoperative valgus malalignment, with an accuracy (95%CI) of 0.862 (0.780-0.944). Conclusion: Overcorrection of a varus knee under valgus stress radiograph (VSR) and excessive MME on preoperative MRI increase the possibility of overcorrection of postoperative alignment in mobile-bearing UKA.

The impact of preoperative MRI-detected lateral meniscal intra-substance signal abnormalities on mid-term functional outcomes following mobile-bearing unicompartmental knee arthroplasty.

PURPOSE: There is a dilemma as to whether the presence of degenerative changes of lateral meniscus is a contraindication to medial unicompartmental knee arthroplasty (UKA). Therefore, the purpose of this study is to assess the influence of preoperative MRI-detected lateral meniscal intra-substance signal abnormalities on mid-term functional outcomes following mobile-bearing UKA. METHODS: We performed a retrospective review of the record on a consecutive series of patients who have undergone mobile-bearing medial UKA from September 2020 to June 2023. The mean duration of follow-up was 2.34 years. All records were collected from case system. MRI assessment of lateral meniscus was performed with the use of the Stoller's classification system. Patients were categorized into two groups (grade 0 and ≥ grade 1). Patient-reported outcomes were assessed with the use of the American Knee Society functional Score (AKSS-F), American Knee Society Objective Score (AKSS-O), and Oxford Knee Score (OKS) preoperatively and at latest follow-up. Furthermore, range of motion (ROM) and hip-knee-ankle angle (HKA) were measured in preoperative and postoperative periods. RESULTS: A total of 92 patients (101 knees) were included in our study. No differences in AKSS-F, AKSS-O, OKS, HKA, or ROM were found between those who showed normal or abnormal signal change of lateral meniscus preoperatively (P < 0.05). Furthermore, there were also no significant differences between two groups concerning AKSS-F, AKSS-O, OKS, HKA, or ROM at latest postoperative follow-up (P < 0.05). Age and duration of disease were independent predictors of low postoperative AKSS-F and AKSS-O (P < 0.05). Nevertheless, ROM was an independent predictor of high postoperative AKKS-O (P < 0.05). Age and female were independent predictors of high postoperative OKS (P < 0.05). CONCLUSION: The presence of preoperative MRI-detected lateral meniscal degenerative changes did not affect mid-term functional outcomes in patients who underwent mobile-bearing medial UKA. On the basis of the results of the current study, we believe that the presence of degenerative changes of lateral meniscus is acceptable in mobile-bearing medial UKA.

Minimally invasive small incision surgical technique for unicompartmental knee arthroplasty.

PURPOSE: It is always a challenge for orthopaedic surgeons to minimise surgical incisions while ensuring excellent surgical results. We propose the minimally invasive small incision (MISI) technique and an extramedullary positioning technique in the unicompartmental knee arthroplasty (UKA) surgery. This study aimed to clarify the early postoperative clinical outcomes and component alignment between MISI and conventional minimally invasive surgical (MIS) techniques. METHODS: We prospectively enrolled 60 patients who underwent MISI-UKA and 60 patients who underwent MIS-UKA as controls. Clinical parameters include the time of straight leg raising, postoperative walking time with walker assistance, hospital stay, Numerical Rating Scale (NRS) pain score and Knee Society Score (KSS). The postoperative components and lower extremity alignment were compared between the two groups with radiographic image measurement. RESULTS: The MISI group obtained a smaller incision during knee extension (P < 0.001) but a longer tourniquet usage time than the MIS group. The MISI group lost less blood (P < 0.001). The MISI group achieved straight leg raising and walking with aid earlier after surgery, with a shorter hospital stay than the MIS group (P < 0.001). Range of motion (ROM), NRS and KSS scores revealed no significant difference between the two groups in six months postoperative follow-up (P > 0.05). Radiographic measurement results between the two groups revealed no statistical difference (P > 0.05) CONCLUSION: The MISI-UKA could achieve faster earlier recovery after surgery and shorter hospital stays without compromising the principles of proper prosthesis position and limb alignment compared with the conventional MIS-UKA.

Intraoperative sensor technology quantifies inter-prosthesis pressure for predicting lower limb alignment after Oxford unicompartmental knee arthroplasty.

Purpose: The aim of this study is to quantify inter-prosthetic pressures at different knee angles in Oxford unicompartmental knee arthroplasty (OUKA) and its correlation with postoperative lower limb alignment. Methods: This study included 101 patients (122 knees) who underwent OUKA from March 2022 to July 2022. The previously designed matrix flexible force sensor was used to measure the inter-prosthesis pressure of different knee joint angles during the UKA operation, and the force variation trend and gap balance difference were obtained. The correlation between inter-prosthesis pressure and postoperative lower limb alignment index including hip-knee-ankle angle (HKAA) and posterior tibial slope (PTS) was analyzed. The effect of PTS change (ΔPTS) on the inter-prosthesis pressure and the range of motion (ROM) of the knee joint was analyzed. Radiographic and short-term clinical outcomes of included patients were assessed. Results: The inter-prosthesis pressure of the different knee joint angles during the operation was not consistent. The mean inter-prosthesis pressure and gap balance difference were 73.68.28 ± 41.65N and 36.48 ± 20.58N. The inter-prosthesis pressure at 0° and 20° was positively correlated with postoperative HKAA (p < 0.001). ΔPTS was positively correlated with the pressure at the end of knee extension and negatively correlated with the pressure at the end of knee flexion (p < 0.001). The HKAA, ROM, degree of fixed knee flexion deformity, and knee society score of the included patients were significantly improved compared with those before the operation (p < 0.001). Conclusion: The inter-prosthesis pressure measured at the knee extension position can predict postoperative HKAA to some degree. Changes in PTS will affect the inter-prosthesis pressure at the end of flexion and end of knee extension, but this change is not related to the range of motion of the knee joint.

Lateral meniscus with tears or with histologic calcification does not increase the risk of lateral osteoarthritis after medial unicompartmental arthroplasty.

PURPOSE: Meniscal tears or histological meniscal calcifications (in the absence of radiological chondrocalcinosis) are frequent in osteoarthritis. Whether lateral meniscal lesions influence clinical outcomes after medial unicompartmental knee arthroplasty (UKA) is unknown. METHODS: We analyzed 130 patients (130 knees) with medial unicompartmental knee arthroplasties between 2005 and 2015. These 130 knees had full articular cartilage thickness in the lateral compartment and no radiological chondrocalcinosis on preoperative radiographs. The lateral meniscus was analyzed with preoperative MRI and a biopsy of the anterior horn at the time of surgery. Synovial fluid was collected and analyzed for calcium pyrophosphate dihydrate crystal deposition (CPPD crystals). Lateral meniscal tears were untreated when detected on MRI or during surgery, with the hypothesis that these tears on the opposite compartment would remain asymptomatic in medial UKA. At average 10-year follow-up, patients were evaluated with clinical and radiographic outcome, with a focus on the risk of joint space narrowing of the lateral femorotibial compartment. RESULTS: CPPD crystals were present in the synovial fluid of 70 knees. Lateral meniscal tears were seen on MRI in 34 (49%) normal meniscuses of the 60 knees without CPPD crystals and in six other knees without histological meniscal calcification despite CPPD crystals. Histological calcification was present on 61 lateral meniscuses with 53 meniscal tears. The results showed no significant differences in the clinical outcomes between knees with lateral meniscal tears or lateral meniscal histological chondrocalcinosis or both lesions and those without these conditions. Additionally, radiographic progression of osteoarthritis in the opposite femorotibial compartment of the knee was not more frequent in patients with these meniscal issues. The ten year cumulative survival rates, measured by the need for total knee arthroplasty, were 91% for knees without meniscal lesions and 92% for knees with these lesions. CONCLUSION: On this basis, treatment of meniscal tears of the lateral compartment and routine aspiration of the knee to assess for birefringent crystals in the planning of medial UKA do not appear necessary.

Clinical Outcomes of Unicompartmental Knee Arthroplasty in Patients with Full-versus Partial-Thickness Cartilage Loss: A Systematic Review and Meta-Analysis.

OBJECTIVE: The objective of the study was to compare postoperative patient-reported outcomes and reoperation rates following unicompartmental knee arthroplasty (UKA) between patients with full-thickness cartilage loss (FTCL) and partial-thickness cartilage loss (PTCL). DESIGN: Multiple databases, including PubMed, Embase, Cochrane Library, and CNKI, were searched until October 2019 for studies comparing the Oxford Knee Score (OKS), American Knee Society (AKS) score, and reoperation rates between patients with FTCL and PTCL following UKA. Data analysis was performed using Review Manager software. RESULTS: A total of 613 UKA cases from 5 retrospective cohort studies were included. The mean difference in postoperative OKSs was significantly higher by 2.92 in FTCL group than in PTCL group (95% confidence interval [CI] = -5.29 to -0.55; P = 0.02). Improvement in OKS was significantly higher by 2.69 in FTCL group than in PTCL group (95% CI = -4.79 to -0.60; P = 0.01). However, the differences in OKSs were not clinically significant. The mean difference in AKS knee scores was similar between the 2 groups (95% CI = -9.14 to -3.34; P = 0.36), whereas the pooled mean difference in AKS function scores was higher by 5.63 in FTCL group than in PTCL group (95% CI = -9.27 to -1.98; P = 0.002), which was clinically relevant. The reoperation rates were statistically higher in PTCL group than in FTCL group (odds ratio = 2.24; 95% CI = 1.15 to 4.38; P = 0.02). CONCLUSIONS: Patients with FTCL achieved superior postoperative patient-reported outcomes and lower reoperation rates following UKA compared with those with PTCL. Thus, we believe this procedure should only be applied to end-stage medial osteoarthritis of the knee joint.

Predicting valgus malalignment after mobile-bearing UKA using a new method: the arithmetic HKA of the arthritic knee.

BACKGROUND: Valgus malalignment is one of the most common reasons for the progression of osteoarthritis in the lateral compartment of the knee after mobile-bearing unicompartmental knee arthroplasty (UKA). The arithmetic hip-knee-ankle angle (aHKA) of the Coronal Plane Alignment of the Knee (CPAK) classification could reflect the constitutional alignment of the arthritic knee. The purpose of this study was to observe the relationship between the aHKA and valgus malalignment after mobile-bearing UKA. METHODS: This retrospective study was conducted using 200 knees undergoing UKA from January 1, 2019, to August 1, 2022. These radiographic signs, including preoperative hip-knee-ankle angle (HKA), mechanical proximal tibial angle (MPTA), mechanical lateral distal femoral angle (LDFA), and postoperative HKA, were measured using standardized weight-bearing long-leg radiographs. Patients with postoperative HKA > 180° and postoperative HKA ≤ 180° were classified as the valgus group and non-valgus group, respectively. The aHKA was calculated as 180° + MPTA - LDFA in this study, which had the same meaning as that (aHKA = MPTA - LDFA) in the CPAK classification. The Spearman correlation analysis, the Mann-Whitney U test, the chi-square test, the Fisher's exact test, and multiple logistic regression were used in the study. RESULTS: Of the 200 knees included in our study, 28 knees were classified as the valgus group, while 172 knees were in the non-valgus group. The mean ± standard deviation (SD) of aHKA (all groups) was 177.04 ± 2.58°. In the valgus group, 11 knees (39.3%) had a value of aHKA > 180°, while 17 knees (60.7%) had a value of aHKA ≤ 180°. In the non-valgus group, 12 knees (7.0%) had a value of aHKA > 180°, while 160 knees (93.0%) had a value of aHKA ≤ 180°. In Spearman correlation analysis, aHKA was positively correlated with postoperative HKA (r = 0.693, p < 0.001). In univariate analysis, preoperative HKA (p < 0.001), LDFA (p = 0.02), MPTA (p < 0.001), and aHKA (p < 0.001) showed significant differences between the valgus and non-valgus groups. Variables with p < 0.1 in univariate analysis were further analyzed using multiple logistic regression analysis, and the variable-aHKA (> 180° vs ≤ 180°, odds ratio (OR) = 5.899, 95% confidence interval (CI) = 1.213 to 28.686, and p = 0.028) was expressed as the risk factor of postoperative valgus malalignment. CONCLUSION: The aHKA is correlated with the postoperative alignment of mobile-bearing UKA and a high aHKA (> 180°) will increase the risk of postoperative valgus malalignment. Therefore, mobile-bearing UKA should be performed with caution in patients with preoperative aHKA > 180°.

Gap balance difference of unicompartmental knee arthroplasty between hanging leg and supine leg position: a prospective cohort study.

PURPOSE: Gap balance is critical in Oxford unicompartmental knee arthroplasty (OUKA) surgery; the effect of lower limb positioning on gap balance judgements has not been reported. There are two mean operative positions for OUKA patients, the hanging leg (HL) and the supine leg (SL) position. This study aimed to investigate the gap balance achieved by current UKA surgical techniques by using a force sensor, to compare the differences in gap balance between the two different positions, and to test whether the difference in gap balance leads to different outcomes in terms of component alignment and early post-operative clinical outcomes. METHODS: This prospective study included 97 knees (76 patients), who underwent OUKA from June 1, 2020, to July 31, 2021, of which 67 knees underwent UKA in the supine leg position and the other 30 in the hanging leg position. When the operator was satisfied with the gap balance, the contact forces between the trial and the spacer block were measured at 90° of knee flexion (flexion gap) and 20° of knee flexion (extension gap) using a pre-developed matrix flexible force sensor. X-rays were reviewed three to five days after surgery. Knee Society Scores (KSS) were obtained at the six month follow-up. RESULTS: Compared to the HL group, the contact force at the flexion gap was higher in the SL group: 55.15N (SD 43.36N) vs. 34.25N (SD 27.56N) (p < 0.05), whereas in the extension gap, there was no significant difference, 90.19 N (SD 43.36N) in the SL group and 86.72N (SD 43.08N) in the HL group (ns.). The contact force was greater in the extension gap than in the flexion gap in both groups (p < 0.01). The gap balance difference in the HL group was 52.46N (SD 31.33N), which was greater than that of the SL group at 35.03N (SD 19.50N) (p < 0.05). There were no significant differences in component alignment or lower limb mechanical alignment between the two groups. There was no significant difference in pre-operative and post-operative KSS between the two groups, while post-operative KSS was significantly higher in both groups compared to the pre-operative period. CONCLUSION: The intra-operative contact forces between the flexion and extension gaps differed in the two groups; the hanging leg position appeared to produce a greater difference in the judgement of gap balance than the supine leg position, but this difference did not adversely affect the alignment of the component or the early post-operative clinical outcome.

Femoral Nerve Block and Local Instillation Analgesia Associated With More Reliable Efficacy in Regional Anesthesia Interventions Within 24 Hours Following Anterior Cruciate Ligament Reconstruction: A Network Meta-analysis.

PURPOSE: To assess the relative effectiveness of different regional anesthetic techniques (peripheral nerve blocks, local instillation analgesia, including intra-articular, subcutaneous, and periarticular infiltration) in patients undergoing anterior cruciate ligament reconstruction (ACLR). METHODS: PubMed, Embase, Cochrane Library, and Web of Science databases were searched from their inception to December 31, 2020. The search was supplemented by manual review of relevant reference lists. Randomized controlled trials of participants after ACLR that compared regional anesthesia interventions were selected. The 2 coprimary outcomes were (1) rest pain scores and (2) cumulative oral morphine equivalent consumption on day 1 (24 hours) post-ACLR. Data were pooled using a Bayesian framework. RESULTS: Of 759 records identified, 46 trials were eligible, evaluating 9 interventions in 3,171 patients. Local instillation analgesia (LIA), including intra-articular, subcutaneous, and periarticular infiltration, had significant improvement in pain relief as compared with placebo (-0.91; 95% CrI -1.45 to -0.37). Femoral nerve block (FNB) also showed significant effects in relieving pain as compared with placebo (-0.70; 95% 95% credible interval [CrI] -1.28 to -0.12). Compared with placebo, a significant reduction in opioid consumption was found in LIA (mean difference -13.29 mg; 95% CrI -21.77 to -4.91) and FNB (mean difference -13.97 mg; 95% CrI -24.71 to -3.04). Femoral and sciatic nerve block showed the greatest ranking for pain relief and opioid consumption without significant evidence (P > .05) to support superiority in comparison with placebo, respectively. CONCLUSIONS: Our meta-analysis shows that FNB and LIA can significantly diminish postoperative pain and reduce opioid consumption following ACLR compared with placebo in the setting of regional anesthesia, and femoral and sciatic nerve block may be the number 1 top-ranked analgesic technique despite high uncertainty. LEVEL OF EVIDENCE: I, Systematic review of Level I studies.

Coronal tibiofemoral subluxation under valgus stress force radiography is useful for evaluating postoperative coronal tibiofemoral subluxation in mobile-bearing UKA.

PURPOSE: Coronal tibiofemoral subluxation (CTFS) is considered a controversial and potential contraindication to unicompartmental knee arthroplasty (UKA) but is less discussed. The study aims to observe the CTFS in a cohort of patients before and after mobile-bearing UKA and to investigate the relationship between preoperative variables (preoperative CTFS and preoperative CTFS under valgus stress) and postoperative CTFS after mobile-bearing UKA. METHODS: The study retrospectively analyzed 181 patients (224 knees) undergoing mobile-bearing UKA from September 1 2019 to December 31 2021. By using hip-to-ankle anterior-posterior (AP) standing radiographs and valgus stress force radiographs, preoperative CTFS, preoperative CTFS under valgus stress, and postoperative CTFS were measured. CTFS was defined as the distance between the tangent line to the outermost joint edge of the lateral condyle of the femur and the tangent line of the lateral tibial plateau. All patients were divided into two groups based on postoperative CTFS, group A (postoperative CTFS ≤ 5 mm) and group B (postoperative CTFS > 5 mm). The Student's t-test, one-way ANOVA together with Tukey's post hoc test, the chi-square test, the Fisher's exact test, Pearson correlation analysis, simple and multiple linear regression, and univariate and multiple logistic regression were used in the analyses. RESULTS: The means ± standard deviations (SD) of preoperative CTFS, preoperative CTFS under valgus stress, and postoperative CTFS were 4.96 ± 1.82 mm, 3.06 ± 1.37 mm, and 3.19 ± 1.27 mm. The difference between preoperative CTFS and postoperative CTFS was statistically significant (p < 0.001). The preoperative CTFS (6.35 ± 1.34 mm) in Group B (n = 22) was significantly higher than that (4.81 ± 1.82 mm) in Group A (n = 202) (p < 0.001), so was the variable-preoperative CTFS under valgus stress (5.41 ± 1.00 mm (Group B) > 2.80 ± 1.14 mm (Group A), p < 0.001). In Pearson correlation analysis, there was a correlation between preoperative CTFS and postoperative CTFS (r = 0.493, p < 0.001), while the correlation between preoperative CTFS under valgus stress and postoperative CTFS was stronger (r = 0.842, p < 0.001). In multiple linear regression analysis, preoperative CTFS under valgus stress (ß = 0.798, 95% confidence interval (CI) = 0.714-0.883, p < 0.001) was significantly correlated with postoperative CTFS. In multiple logistic regression analysis, preoperative CTFS under valgus stress (OR = 12.412, 95% CI = 4.757-32.384, and p < 0.001) was expressed as the risk factor of postoperative CTFS (> 5 mm). CONCLUSION: Preoperative CTFS can be improved significantly after mobile-bearing UKA. In addition, postoperative CTFS is correlated with preoperative CTFS under valgus stress and a higher preoperative CTFS under valgus stress will increase the risk of higher postoperative CTFS (> 5 mm). LEVEL OF EVIDENCE: Level III.

Clinical and radiological outcomes of jumbo cup in revision total hip arthroplasty: A systematic review.

Introduction: Many studies have reported the clinical outcomes of a jumbo cup in revision total hip arthroplasty (rTHA) with acetabular bone defect. We conducted a systematic review to access the survivorship and clinical and radiological outcomes of a jumbo cup in rTHA. Methods: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive literature search from PubMed, MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews was performed with the keywords ("revision" OR "revision surgery" OR "revision arthroplasty") AND ("total hip arthroplasty" OR "total hip replacement" OR "THA" OR "THR") AND ("jumbo cup" OR "jumbo component" OR "extra-large cup" OR "extra-large component"). Studies reporting the clinical or radiological outcomes were included. The basic information and radiological and clinical results of these studies were extracted and summarized for analysis. Results: A total of 19 articles were included in the systematic review. The analysis of clinical results included 953 hips in 14 studies. The re-revision-free survivorship of the jumbo cup was 95.0% at a mean follow-up of 9.3 years. Dislocation, aseptic loosening, and periprosthetic joint infection were the top three complications with an incidence of 5.9%, 3.0%, and 2.1%, respectively. The postrevision hip center was relatively elevated 10.3 mm on average; the mean postoperative leg-length discrepancy was 5.4 mm. Conclusion: A jumbo cup is a favorable option for acetabular bone defect reconstruction in rTHA with satisfying survivorship and acceptable complication rates.

Sensor Assessment of Gap Balance in Mobile-Bearing Unicompartmental Knee Arthroplasty.

The most important procedure of mobile-bearing unicompartmental knee arthroplasty (UKA) is to balance the knee flexion and extension gap. Conventionally, the balance was determined by the subjective assessment of plugging out the feeling gauge. Since it mainly depended on the surgeons' experience, the accuracy was always in doubt. In the past 10 years, pressure sensors have been introduced to guide the gap balance in total knee arthroplasty (TKA). However, the sensor technique was introduced to UKA very recently. Herein is our sensor assessment of the gap balance in 20 cases UKA by one experienced surgeon. The sensor was a custom-designed force sensor matrix according to the shape of the tibial trial of mobile-bearing UKA. The postoperative clinical outcomes and radiographic results were recorded for future comparison. We aim to use this method to assess more than 200 cases of UKA by various surgeons to ultimately standardize the gap-balance result.

Unicompartmental Knee Arthroplasty for Knee Osteoarthritis With the Pellegrini-Stieda Lesion: A Case Report.

Pellegrini-Stieda lesion is described as ossification on the origin of medial collateral ligament. We present a case of end-stage knee osteoarthritis with the Pellegrini-Stieda lesion treated by unicompartmental knee arthroplasty (UKA). During the postoperative follow-up, an interesting change occurred such that the ossification lesion disappeared gradually and did not relapse. It is supposed that the disappearance was caused by UKA changing the abnormal biomechanics of the varus osteoarthritic knee.

A radiographic model predicting the status of the anterior cruciate ligament in varus knee with osteoarthritis.

PURPOSE: The study aims to investigate the accuracy of different radiographic signs for predicting functional deficiency of anterior cruciate ligament (ACL) and test whether the prediction model constructed by integrating multiple radiographic signs can improve the predictive ability. METHODS: A total number of 122 patients from January 1, 2018, to September 1, 2021, were enrolled in this study. Among them, 96 patients were classified as the ACL-functional (ACLF) group, while 26 patients as the ACL-deficient (ACLD) group after the assessment of magnetic resonance imaging (MRI) and the Lachman's test. Radiographic measurements, including the maximum wear point of the proximal tibia% (MWPPT%), tibial spine sign (TSS), coronal tibiofemoral subluxation (CTFS), hip-knee-ankle angle (HKA), mechanical proximal tibial angle (mPTA), mechanical lateral distal femoral angle (mLDFA) and posterior tibial slope (PTS) were measured using X-rays and compared between ACLF and ACLD group using univariate analysis. Significant variables (p < 0.05) in univariate analysis were further analyzed using multiple logistic regression analysis and a logistic regression model was also constructed by multivariable regression with generalized estimating models. Receiver-operating-characteristic (ROC) curve and area under the curve (AUC) were used to determine the cut-off value and the diagnostic accuracy of radiographic measurements and the logistic regression model. RESULTS: MWPPT% (odds ratio (OR) = 1.383, 95% confidence interval (CI) = 1.193-1.603, p < 0.001), HKA (OR = 1.326, 95%CI = 1.051-1.673, p = 0.017) and PTS (OR = 1.981, 95%CI = 1.207-3.253, p = 0.007) were shown as predictive indicators of ACLD, while age, sex, side, TSS, CTFS, mPTA and mLDFA were not. A predictive model (risk score = -27.147 + [0.342*MWPPT%] + [0.282*HKA] + [0.684*PTS]) of ACLD using the three significant imaging indicators was constructed through multiple logistic regression analysis. The cut-off values of MWPPT%, HKA, PTS and the predictive model were 52.4% (sensitivity:92.3%; specificity:83.3%), 8.5° (sensitivity: 61.5%; specificity: 77.1%), 9.6° (sensitivity: 69.2%; specificity: 78.2%) and 0.1 (sensitivity: 96.2%; specificity: 79.2%) with the AUC (95%CI) values of 0.906 (0.829-0.983), 0.703 (0.574-0.832), 0.740 (0.621-0.860) and 0.949 (0.912-0.986) in the ROC curve. CONCLUSION: MWPPT% (> 52.4%), PTS (> 9.6°), and HKA (> 8.5°) were found to be predictive factors for ACLD, and MWPPT% had the highest sensitivity of the three factors. Therefore, MWPPT% can be used as a screening tool, while the model can be used as a diagnostic tool.

Pneumocystis jiroveci pneumonia after total hip arthroplasty in a dermatomyositis patient: A case report.

BACKGROUND: Pneumocystis jiroveci pneumonia (PJP) is a serious opportunistic infection that occurs mostly in patients with immunodeficiency and long-term immunosuppressive therapy. In non-human immunodeficiency virus-infected patients, the most important risk factor for PJP is the use of glucocorticoids in combination with other immunosuppressive treatments. The management of glucocorticoids during the perioperative period in patients with dermatomyositis requires special care. CASE SUMMARY: We report a case of PJP in the perioperative period. A 61-year-old woman with a history of anti-melanoma differentiation-associated gene 5 (MDA5)-positive dermatomyositis and interstitial pneumonia was administered with long-term oral methylprednisolone and cyclosporine. The patient underwent right total hip arthroplasty in the orthopaedic department for bilateral osteonecrosis of the femoral head. She was given intravenous drip hydrocortisone before anesthesia and on the first day after surgery and resumed oral methylprednisolone on the second postoperative day. On the fifth day after surgery, the patient suddenly developed dyspnea. The computed tomography scan showed diffuse grid shadows and ground glass shadows in both lungs. Polymerase chain reaction testing of bronchoalveolar lavage fluid was positive for Pneumocystis jiroveci. The patient was eventually diagnosed with PJP and was administered with oral trimethoprim-sulfamethoxazole. At the 6-mo review, there was no recurrence or progression. CONCLUSION: Continued perioperative glucocorticoid use in patients with anti-MDA5-positive dermatomyositis may increase the risk of PJP.

Efficacy and Safety of Intra-Articular Platelet-Rich Plasma in Osteoarthritis Knee: A Systematic Review and Meta-Analysis.

BACKGROUND: Knee osteoarthritis (KOA) is a common disease in aged adults. Intra-articular (IA) injection of platelet-rich plasma (PRP) therapy is an effective minimally invasive treatment for KOA. We aimed to compare the efficacy and safety of platelet-rich plasma (PRP) with placebo or other conservative treatments. METHODS: We conducted a meta-analysis to identify relevant articles from online register databases such as PubMed, Medline, Embase, and the Cochrane Library. The primary outcomes were the visual analogue scale (VAS) score, Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, and International Knee Documentation Committee (IKDC) subjective score. The secondary outcome was the adverse event rate. RESULTS: A total of 895 articles were identified, of which 23 randomized controlled trials that met the inclusion criteria were determined as eligible. Compared with placebo, PRP had a lower VAS score and higher IKDC subjective score at the 6th month after treatment and significantly less WOMAC score during the follow-up period. Compared with oral NSAIDs, PRP gained a lower WOMAC score at the 6th month after treatment. The VAS score decreased after treatment when reaching PRP and CS. As compared to the HA, the VAS score, WOMAC score, and IKDC subjective score all revealed better PRP results. There were no significant differences in adverse event rates comparing PRP versus placebo or HA. Different PRP applications did not show significant differences in VAS score in the 1st month and WOMAC score in the 3rd month after treatment. CONCLUSION: To compare with the conservative treatments mentioned above, PRP is more effective in relieving symptoms. There were no significant differences between triple PRP application and single PRP application in short-term curative effect.

Cannulated screw fixation versus plate fixation in treating displaced intra-articular calcaneus fractures: a systematic review and meta-analysis.

BACKGROUND: Operative treatment has become the current trend for displaced intra-articular calcaneus fracture (DIACF), while using cannulated screw fixation or plate fixation is still controversial for treating DIACF. The purpose of this meta-analysis is to compare the outcome of the two fixation methods. METHODS: We searched literature comparing cannulated screw fixation and plate fixation from PubMed, Embase, Web of Science, and Cochrane Library. Only randomized controlled trials were included. The outcomes of post-operative function, radiological measurement, time efficiency, and wound complications were pooled in the meta-analysis. RESULT: Seven RCTs with 902 cases of DIACF were included. Pooled results showed the two fixation methods that had similar function satisfactory of AOFAS score (RR = 0.95, 95% CI = [0.83, 1.09], P = 0.47, I2 = 0%) and Maryland Foot score (RR = 0.93, 95% CI = [0.68, 1.28], P = 0.66, I2 = 84%). Compared to plate fixation, cannulated screw fixation had better improvement of Bohler's angle (WMD = 0.56, 95% CI = [0.20, 0.91], P = 0.002, I2 = 34%) and Gissane's angle (WMD = 1.36, 95% CI = [0.56, 2.16], P = 0.0008, I2 = 7%), better recovery of calcaneal height (WMD = 0.49, 95% CI = [0.02, 0.95], P = 0.04, I2 = 6%), shorter time to operation (WMD = - 2.91, 95% CI = [- 4.99, - 0.84], P = 0.006, I2 = 97%), less operation time (WMD = - 21.58, 95% CI = [- 37.31, - 5.85], P = 0.007, I2 = 98%), reduced length of hospital stay (WMD = - 2.00, 95% CI = [- 3.69, - 0.31], P = 0.02, I2 = 97%), and less wound complications (RR = 0.16, 95% CI = [0.08, 0.32], P < 0.00001, I2 = 0%). CONCLUSION: Cannulated screw fixation and plate fixation have similar postoperative functional satisfactory. Cannulated screw fixation is superior to plate fixation in reduction quality, time efficiency, and wound complications.

Patient-specific instrumentation (PSI) in total ankle arthroplasty: a systematic review.

BACKGROUND: Patient-specific instrument (PSI) may theoretically make total ankle arthroplasty (TAA) more accurate. Several studies have reported the outcomes of PSI TAA. The aim of this study is to systematically review the literature of PSI TAA. METHODS: PubMed, Embase, Web of Science, and Cochrane Library databases were systematically reviewed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines for PSI TAA. The quality of the included studies was evaluated according to Methodological Index for Non-Randomized Studies (MINORS). RESULT: Nine articles were ultimately included in the systematic review. The implant position and function outcome of TAA was similar between PSI and SI. Prediction accuracy of implant size remained great difference. PSI can shorten the operative time and fluoroscopy time. The quality of current studies on PSI TAA is insufficient to produce high-level evidence. CONCLUSION: PSI can get similar implant position and clinical outcome in TAA compared to SI, but current evidence is not strong enough to evaluate PSI TAA.

Sensor and machine learning-based assessment of gap balancing in cadaveric unicompartmental knee arthroplasty surgical training.

PURPOSE: The aim of this study was to assess the difference between flexion and extension contact forces-gap balance-after Oxford mobile-bearing medial unicompartmental knee arthroplasty (UKA) performed by surgeons with varying levels of experience. METHODS: Surgeons in a training programme performed UKAs on fresh frozen cadaveric specimens (n = 60). Contact force in the medial compartment of the knee was measured after UKA during extension and flexion using a force sensor, and values were clustered using an unsupervised machine learning (k-means algorithm). Univariate analysis was performed with general linear regression models to identify the explanatory variable. RESULTS: The level of experience was predictive of gap balance; surgeons were clustered into beginner, mid-level and experienced groups. Experienced surgeons' mean difference between flexion and extension contact force was 83 N, which was significantly lower (p < 0.05) than that achieved by mid-level (215 N) or beginner (346 N) surgeons. CONCLUSION: We found that the lowest mean difference between flexion and extension contact force after UKA was 83 N, which was achieved by surgeons with the most experience; this value can be considered the optimal value. Beginner and mid-level surgeons achieved values that were significantly lower. This study also demonstrates that machine learning can be used in combination with sensor technology for improving gap balancing judgement in UKA.