BACKGROUND:Lateral unicompartmental knee arthroplasty (LUKA) is a technically demanding procedure for isolated lateral compartment osteoarthritis, but the impact of preoperative valgus deformity severity on patient satisfaction remains unclear. METHODS:This retrospective study analyzed 62 patients who underwent fixed-bearing LUKA, stratified by preoperative valgus angle into mild (≤ 6°, n = 35), moderate (6 to 12°, n = 16), and severe (greater than 12°, n = 11) groups. Outcomes at a mean follow-up of 35 months (range, 24 to 71 months), including radiographic alignment, Oxford Knee score, complications, and patient satisfaction, were assessed and compared. RESULTS:At a mean follow-up of 35 months, patient satisfaction demonstrated a significant nonlinear relationship with preoperative valgus deformity severity. The moderate valgus group (6 to 12°) achieved the highest rate of "Very Satisfied" outcomes (75.0%), significantly surpassing both the mild (34.3%) and severe (9.1%) groups. Postoperative Oxford Knee scores and functional improvement were also optimal in the moderate group, while the severe group reported the lowest scores and the highest complication rate (36.4%). Radiographically, the moderate group achieved a mean postoperative valgus alignment of 5.8 ± 1.2°, which aligns with the proposed ideal range for LUKA. In contrast, the severe group exhibited under-correction (postoperative 8.0 ± 1.3° from 13.5 ± 0.6°), and the mild group trended toward potential overcorrection (postoperative 2.1 ± 1.0°). Patient-reported reasons for dissatisfaction distinctly differed: persistent pain was predominant in the mild group (56.5%), while instability dominated in the severe group (90.0%). CONCLUSION:Moderate valgus deformity represents the optimal indication for LUKA, yielding the highest patient satisfaction. This is likely due to the achievability of ideal postoperative valgus alignment and the match between surgical reconstruction and the characteristic posterior femoral condyle wear pattern of the lateral compartment. These findings provide crucial guidance for patient selection in LUKA.

BACKGROUND:The aim of this study was to ascertain whether mild cartilage damage of the lateral condyle of the femur influences the mid-term clinical outcomes of medial unicompartmental knee arthroplasty (mUKA) and exacerbates the progression of osteoarthritis in the lateral compartment. METHODS:Patients with normal cartilage or mild cartilage damage of the lateral femoral condyle (Outerbridge grade, ≤II) who underwent mUKA between March 2016 and December 2020 were retrospectively divided into 4 groups: a normal cartilage group and a cartilage damage group that was subdivided on the basis of the damage location (weight-bearing area, posterior weight-bearing area, and medial side of the lateral condyle). Patients with postoperative overcorrection of limb alignment or preoperative lateral meniscal extrusion were excluded. Outcomes that were compared among the groups included the hip-knee-ankle angle (HKA), lateral compartment Kellgren-Lawrence (K-L) grade, Oxford Knee Score (OKS), Forgotten Joint Score (FJS), Kujala score, patient satisfaction, and complications. RESULTS:The study included 203 knees in 177 patients (136 female patients; 177 East Asian; mean age, 68.3 ± 7.1 years) with a mean follow-up of 70.8 months (range, 48 to 106 months). The postoperative OKS, FJS, and Kujala score showed no significant differences among the groups. Mid-term full-length standing radiographs of the lower limbs were obtained for 99 of the 203 knees, with a mean follow-up of 54.1 months (range, 49 to 104 months). Of the 99 knees, 26 (26.3%) showed an increase of 1 K-L grade in the lateral compartment and 73 (73.7%) remained unchanged. Three knees (1.5%) from the normal group experienced complications, including 1 periprosthetic fracture, 1 bearing dislocation, and 1 bearing rotation, but none required conversion to TKA. CONCLUSIONS:In patients in whom postoperative alignment is not overcorrected and preoperative lateral meniscal function is intact, mild cartilage damage (Outerbridge grade I or II) of the lateral femoral condyle does not impact the mid-term clinical outcomes of mUKA and does not exacerbate the progression of osteoarthritis in the lateral compartment. LEVEL OF EVIDENCE:Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: This study aimed to evaluate whether preoperative anxiety and/or depression (AD) is associated with mid-term lateral compartment osteoarthritis progression (LOP) after medial unicompartmental knee arthroplasty (mUKA). Methods: This retrospective observational cohort study analyzed a prospectively maintained institutional database of consecutive patients who underwent mUKA between March 2016 and December 2020. Preoperative psychological status was assessed using the Hospital Anxiety and Depression Scale (HADS); patients with subscore ≥8 were categorized as having AD. Clinical outcomes included Oxford Knee Score (OKS), Forgotten Joint Score (FJS), Kujala score, and complications at a mean follow-up of 70 months. Serial full-length standing radiographs were used to measure coronal alignment and Kellgren–Lawrence (K/L) grade in the lateral compartment. LOP was defined as an increase of ≥1 K/L grade between the early postoperative and final follow-up radiographs. Univariate and multivariable logistic regression were used to identify factors associated with LOP. Results: A total of 203 knees met the inclusion criteria; 26 knees were classified into the AD group and 177 into the Non-AD group. At final follow-up, the AD group had worse OKS, smaller OKS improvement, and lower FJS and Kujala scores. Radiographic follow-up was available in 99 knees. LOP occurred in 26.3% of knees overall. The rate of LOP was significantly higher in the AD group than in the Non-AD group (60.0% vs. 20.2%). In univariate analysis, AD was associated with LOP. In multivariable logistic regression, preoperative AD remained associated with a higher likelihood of LOP after adjustment for prespecified covariates. Conclusions: Preoperative anxiety and/or depression was associated with a higher frequency of radiographic lateral compartment osteoarthritis progression and worse mid-term patient-reported outcomes after mUKA. These findings should be considered exploratory and hypothesis-generating.

BACKGROUND:Anteromedial osteoarthritis (AMOA) is characterized by focal cartilage loss on the anteromedial tibial plateau. While medial tibial plateau depth (MTPD) is known to influence knee biomechanics, its direct relationship with cartilage lesion severity in AMOA remains unclear. This study investigated whether a shallower MTPD is associated with more severe cartilage damage in AMOA. METHODS:This retrospective study included 240 patients with AMOA. MTPD and other radiographic parameters (hip-knee-ankle angle - HKAA, joint line convergence angle - JLCA, posterior tibial slope - PTS) were measured from radiographs and MRI. Medial meniscal status (tear, extrusion) was also assessed on MRI. Cartilage lesion severity was assessed arthroscopically and graded using the International Cartilage Repair Society (ICRS) classification system. Statistical analyses included correlation, receiver operating characteristic (ROC) curve analysis, and multivariate regression to identify factors associated with cartilage damage. RESULTS:A shallower MTPD was significantly correlated with higher ICRS grades on both the medial tibial plateau (MTP) and medial femoral condyle (MFC) (r ≈ -0.43, p < 0.001). ROC analysis showed MTPD had acceptable discriminative ability for identifying ICRS grade >1 lesions within this cohort (AUC: 0.729 for MTP, 0.716 for MFC). Multivariate regression confirmed MTPD as an independent factor associated with higher ICRS grade, alongside higher age, BMI, meniscal extrusion, and JLCA, and lower HKAA. PTS was not significantly associated with ICRS grade. CONCLUSION:A shallower medial tibial plateau depth is significantly associated with more severe cartilage lesions in anteromedial knee osteoarthritis. This morphological feature may contribute to the pathomechanics of AMOA, and its assessment could aid in patient stratification. Further longitudinal studies are warranted to establish causality.

PURPOSE:Lateral compartment osteoarthritis progression (LOP) is a major cause of mid to long-term failure after medial unicompartmental knee arthroplasty (mUKA). This study investigated whether preoperative frailty predicts LOP after mUKA over a mean 70-month follow-up. METHODS:We retrospectively identified consecutive patients who underwent Oxford Phase III mobile-bearing mUKA between March 2016 and December 2020. Preoperative frailty was assessed with the Clinical Frailty Scale (CFS), and patients were classified as robust (Clinical Frailty Scale ≤ 3) or frail (CFS > 3). To minimize mechanical confounding, cases with postoperative coronal overcorrection and those with preoperative lateral meniscal extrusion on MRI were excluded. Outcomes included hip-knee-ankle angle, lateral compartment Kellgren-Lawrence (K/L) grade, Oxford Knee Score, Forgotten Joint Score, Kujala score, perioperative complications, and revision or conversion to total knee arthroplasty. Univariate and multivariable logistic regression identified risk factors of LOP. RESULTS:A total of 203 knees (101 robust; 102 frail) from 177 patients were analyzed (mean follow-up, 70.8 months). Baseline characteristics were comparable except for age. At the final follow-up, the frail group had lower OKS (39.39 vs 43.06; P < 0.001), FJS (79.56 vs 89.40; P < 0.001), and Kujala scores (59.88 vs 67.71; P < 0.001), and a smaller OKS gain (13.47 vs 18.72; P < 0.001). Five-year standing radiographs were available for 99 of 203 knees (48.8%): 26 of 99 (26.3%) showed a 1-grade increase in lateral K/L, while 73 of 99 (73.7%) remained unchanged. LOP was more frequent in frail versus robust knees (41.7% vs 11.8%; P = 0.001). On multivariable analysis, frailty independently predicted LOP (OR = 4.36; 95% CI, 1.37-13.90; P = 0.013). LOP increased across higher CFS strata within the frail subgroup (P = 0.043). CONCLUSION:Preoperative frailty is common and independently associated with a higher midterm risk of lateral compartment progression after mUKA, with risk escalating at higher frailty levels. CFS-based stratification provides a practical adjunct for preoperative counseling, expectation setting, and perioperative planning in candidates for mUKA.

Aims:Although the influence of medial bone marrow lesions (BMLs) on outcomes after medial unicompartmental knee arthroplasty (UKA) has been studied, the impact of concomitant lateral compartmental BMLs remains unclear. This study aims to determine whether the lateral BMLs, in addition to medial BMLs, influence clinical outcomes in patients undergoing medial UKA. Methods:We retrospectively reviewed patients who underwent medial UKA between January 2016 and December 2019 and had preoperative MRI. A total of 86 patients with isolated medial BMLs (BML-M) and 38 with combined medial and lateral BMLs (BML-M+L) were included. Clinical outcomes were assessed using the Numeric Rating Scale (NRS) and Oxford Knee Score (OKS). Radiological evaluation included pathological radiolucent lines, osteoarthritis progression in the lateral compartment, mechanical femorotibial angle (mFTA), and postoperative alignment zones. The proportion of patients achieving the minimal clinically important difference (MCID) for each score and a well-aligned mechanical axis was also calculated. Multivariable linear regression was employed to determine whether concomitant lateral BMLs independently influenced OKS improvement. Results:The mean follow-up was 6.4 years (SD 1.1). Both groups demonstrated significant improvements from baseline in NRS and OKS (both p < 0.001). No significant differences were found in preoperative and postoperative mFTA between the two groups. No pathological radiolucent lines were detected in either group and no significant difference was found in the radiological progression of the lateral compartment between the BML-M group and the BML-M+L group (12.8% (n = 11) vs 13.1% (n = 5); p = 0.550). There were no between-group differences in either preoperative or postoperative scores, or in the proportion of patients reaching the MCID for NRS or OKS, or in the patients attaining a well-aligned mechanical axis. In the multivariable model, combined medial and lateral compartmental BMLs were not independently associated with OKS improvement (β = 0.548 (95% CI -3.400 to 4.490); p = 0.784). Conclusion:In MRI-selected medial UKA patients with medial BMLs, mild concomitant lateral BMLs, in the absence of severe lateral cartilage wear and lateral meniscal extrusion, were not associated with inferior mid-term patient-reported outcomes or alignment.

Deep vein thrombosis (DVT) is a feared postoperative complication following knee arthroplasty. However, the incidence of acute DVT, associated early risk stratification models, and optimal thromboprophylaxis after unicompartmental knee arthroplasty (UKA) remain unclear. This study aimed to comprehensively evaluate the perioperative dynamics of systemic-inflammatory and hemostatic molecular markers in patients with knee osteoarthritis undergoing UKA and to analyze their association with the occurrence of acute DVT. The first multi-center prospective study enrolled consecutive patients undergoing unilateral UKA without routine postoperative pharmacological thromboprophylaxis from three institutions (two for derivation and one for external validation). Systemic-inflammatory and hemostatic molecular markers were measured at admission, 2-hour, 1-day, and 3-day post-UKA. Lower-extremity ultrasound was routinely conducted prior to and at 4–5 days following UKA to detect asymptomatic and symptomatic DVT. Temporal trends in these biomarkers and their relationship with acute DVT were analyzed. A nomogram was then developed to visualize individualized near-term risk stratification of acute postoperative DVT. Finally, a retrospective cohort of UKA-treated patients who received routine thromboprophylaxis was enrolled to evaluate the risk stratification performance of the identified indicators in an anticoagulated population. The derivation cohort included 87 patients (mean age 67.8 ± 6.5 years, 78.2

BACKGROUND:Patient-specific instrumentation (PSI) can be applied in unicompartmental knee arthroplasty (UKA) to assist surgeons in planning and positioning prostheses. This study aims to compare the accuracy of prosthesis positioning in medial UKA performed with a newly designed PSI tool to those of UKA performed with robotic assistance and previously reported PSI-assisted techniques. MATERIALS AND METHODS:Ninety-one patients underwent medial mobile-bearing UKA with the new PSI tool designed based on preoperative CT scans from May 2023 to June 2024. Deviations between planned and actual postoperative positions of femoral and tibial components in the coronal, sagittal, and axial planes were measured with CT overlay, and root mean square error (RMSE) was calculated. Accuracy was benchmarked by comparing the proportion of deviations within 2° with published robotic-assisted UKA data. Median absolute deviation (MAD) was compared with those of previous PSI studies. Cases of prosthesis size adjustment and PSI failure were also recorded. RESULT:RMSE values for femoral component angle deviations were 2.0°, 3.7°, and 2.8° in coronal, sagittal, and axial planes; for the tibial component, values were 1.5°, 1.8°, and 2.6°, respectively. MAD values were consistently low, and angular deviations were generally comparable or superior to robotic-assisted UKA. In 4 cases (4.4%), prosthetic size was adjusted intraoperatively. CONCLUSION:The newly designed PSI tool effectively achieves the preoperative planning goals in medial mobile-bearing UKA. When compared with the published results of robotic-assisted and PSI-guided UKA, this tool provides comparable or even superior component positioning accuracy, demonstrating its potentials for wider clinical applications.

Medical ozone is a molecule composed of three oxygen atoms with anti-inflammatory, analgesic, and antioxidant functions. Ozone therapy (O 3 or O 2 - O 3 ) for knee osteoarthritis has gradually received increasing attention from researchers in recent years. Here, we discuss the research hotspots and development trends of ozone therapy for knee osteoarthritis through literature visualization and analysis. (1) From 2012 to the present, the overall trend of publications on ozone treatment for knee osteoarthritis has been increasing annually, and it has received widespread attention, especially in Iran and China. (2) Keyword analysis revealed that the keywords with the greatest number of citations for ozone treatment of knee osteoarthritis are "osteoarthritis," "ozone," "knee osteoarthritis," "ozone therapy," and "hyaluronic acid." (3) The results of the cocitation analysis revealed that the themes of the cocited literature are concentrated in 11 directions: intra-articular injections, intra-articular oxygen ozone, treatment of knee osteoarthritis, rehabilitation studies, time effects, pain function, comprehensive review, growth factors, rheumatic diseases, ultrasound-guided corticosteroid injections, and placebo. (4) The hotspots of the available highly cited literature have focused mainly on the efficacy and safety of ozone or growth factors alone in the treatment of knee osteoarthritis. Most of the literature suggests that intra-articular injections are the most common form of ozone therapy, and the accuracy and safety of ozone injections can be ensured using ultrasound-guided techniques. Ozone therapy has a positive short-term effect on pain control and functional recovery within 6 months after injection, but how to maintain the long-term efficacy of ozone therapy has rarely been described. It is hypothesized that the combination of ozone and growth factors may be beneficial for prolonging the efficacy of ozone therapy. (5) Ozone therapy has no advantages over other therapies in terms of therapeutic efficacy. Compared with ozone therapy, platelet-rich plasma and growth factor-rich plasma have better long-term outcomes in the treatment of knee osteoarthritis, whereas stromal vascular components have the best effects on pain relief and functional improvement. Few studies address the combination of ozone and growth factors for the treatment of knee osteoarthritis, and a few clinical studies registered have explored other treatments (e.g., corticosteroids). (6) Future studies could further explore the specific mechanisms and optimal dosing regimens of ozone combined with different growth factors in the treatment of knee osteoarthritis to compensate for the short-term efficacy of ozone therapy and to validate the long-term efficacy and safety of this combination therapy. It is also imperative to develop international guidelines for ozone therapy for osteoarthritis of the knee as soon as possible.

Abstract Intermittent hypoxia has been reported to contribute beneficial effects on fracture healing depending on various factors like duration, frequency, and severity. Yet, little is known about the underlying molecular mechanism. Our previous study found that LINC00323 was up-regulated under hypoxic conditions, suggesting that it might play a final role in hypoxia-induced fracture repair. The present study is to investigate the osteogenic effect of LINC00323 in vitro and in vivo. Upregulation of LINC00323 enhanced the mineralization and activity ALP and increased the expression of osteogenic markers. Further analysis revealed that LINC00323 promoted PDGFB expression by binding FUS to regulate the growth and osteogenic differentiation of MC3T3-E1. Lentivirus mediated LINC00323 particles were injected into the fracture site of the tibia of mice, and fracture healing was evaluated by X-rays, micro-CT examination, biomechanical test and histological staining. Local injection of Lentivirus-LINC00323 increased bone mass, biomechanical strength and cartilage callus formation. These findings indicated that LINC00323 induced the differentiation of osteoblast-like cells via regulation of the expression of PDGFB, represents a theoretical basis to accelerate fracture healing.

Peripheral nerve injury (PNI) usually has a poor effect on functional recovery and severely declines the patient’s quality of life. Our prior findings indicated that hypoxia remarkably promoted nerve regeneration of rats with sciatic nerve transection. However, the underlying molecular mechanisms of hypoxia in functional recovery of PNI still remain elusive. In this research, we tried to explain the functional roles and mechanisms of hypoxia and the hypoxia-inducible factor-1α (HIF-1α) in PNI. Our results indicated that hypoxia promoted proliferation and migration of dorsal root ganglia (DRG) and increased the expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). Mechanistically, hypoxia suppressed ferroptosis through activating HIF-1α in DRG neurons. Gain and loss of function studies were performed to evaluate the regulatory roles of HIF-1α in ferroptosis and neuron recovery. The results revealed that up-regulation of HIF-1α enhanced the expression of solute carrier family membrane 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) and increased the contents of cysteine and glutathione, while inhibiting the accumulation of reactive oxygen species (ROS). Our findings provided novel light on the mechanism of ferroptosis involved in PNI and manifest hypoxia as a potential therapeutic strategy for PNI recovery.

膝单髁置换术(UKA)近年来在国内发展迅速,同时加速康复外科理念在关节外科领域不断深化,做好围手术期管理是保证手术成功、获得快速康复的关键环节.为减轻患者围手术期的创伤和应激反应,优化围手术期管理模式,提高UKA的疗效并促进其标准化、规范化,中国研究型医院学会关节外科学专业委员会膝关节部分置换研究学组在2020年制定推出《膝关节单髁置换术围手术期管理专家共识》,本文对其中重点内容和热点问题进行解读,与同道交流.

Abstract Background The cartilage quality of the lateral compartment needs to be clarified prior to medial unicompartmental knee arthroplasty (UKA). Valgus stress radiograph has been recommended as the preferred tool. Some studies also show that magnetic resonance imaging (MRI) has a higher diagnostic value. So, we conducted this study to compare whether valgus stress radiographic lateral joint space width (LJSW) and MRI grading can accurately reflect cartilage quality and its screening value for UKA-suitable patients. Methods One hundred and thirty eight knees proposed for UKA were enrolled prospectively. Valgus stress radiograph was taken to measure LJSW. LJSW > 4 mm was considered normal and suitable for UKA. For weight-bearing area cartilage of lateral femoral condyle, Recht grade was assessed by MRI preoperatively. Recht grades ≤ 2 were treated as non-high-grade injuries while Recht grades > 2 were treated as high-grade injuries. Outerbridge grade was the gold standard and was assessed intraoperatively. Patients with Outerbridge grades 0–2 (non-high-grade injuries) underwent UKA, and patients with Outerbridge grades 3–4 (high-grade injuries) underwent total knee arthroplasty (TKA). The diagnostic parameters of valgus stress radiograph and MRI for the selection of UKA candidates were calculated, and receiver operating characteristic curves were drawn. P < 0.05 was considered significant. Results Of 138 knees, 120 underwent UKAs, and 18 underwent TKAs. In terms of selecting UKA candidates, the sensitivity was close between MRI (95.0%) and valgus stress radiograph (96.7%), and the specificity, accuracy, positive predictive value and negative predictive value of MRI (94.4%, 94.9%, 99.1%, 73.9%, respectively) were higher than that of valgus stress radiograph (5.9%, 85.5%, 88.0%, 20.0%, respectively). The difference in area under the curve (AUC) between MRI (0.950) and LJSW (0.602) was significant (P = 0.001). Conclusion Compared with valgus stress radiograph, MRI has excellent evaluation value in diagnosing lateral weight-bearing cartilage injuries and can be used as a reliable tool for selecting suitable UKA patients.

The recovery of peripheral nerve injury (PNI) is not ideal in clinic. Our previous study revealed that hypoxia treatment promoted PNI repair by inhibiting ferroptosis. The aim of this study was to investigate the underlying molecular mechanism of HIF-1α in hypoxia-PNI recovery. M6A dot blot was used to determine the total level of m6A modification. Besides, HIF-1α small interfering RNA (siRNA) or IGF2BP1 overexpression vector was transfected into dorsal root ganglion (DRG) neurons to alter the expression of HIF-1α and IGF2BP1. Subsequently, MeRIP-PCR analysis was applied to validate the m6A methylation level of SLC7A11. We demonstrated the hypoxia stimulated HIF-1α-dependent expression of IGF2BP1 and promoted the overall m6A methylation levels of DRG neurons. Overexpression of HIF-1α increased the expressions of neurotrophic factors including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and glial-derived neurotrophic factor (GDNF), which could be effectively reversed by siRNA knockdown of IGF2BP1. Moreover, upregulation of HIF-1α contributed to the m6A methylation level and mRNA stabilization of SLC7A11. This study revealed that the HIF-1α/IGF2BP1/SLC7A11 regulatory axis facilitated the recovery of injured DRG neurons. Our findings suggest a novel insight for the m6A methylation modification in PNI recovery.

Unicompartmental knee arthroplasty (UKA) is an effective treatment for end-stage anteromedial osteoarthritis (AMOA). The key to UKA is the flexion-extension gap balance, which is closely related to postoperative complications such as bearing dislocation, bearing wear, and arthritis progression. The traditional gap balance assessment is performed by indirectly sensing the tension of the medial collateral ligament by a gap gauge. It relies on the surgeon's feel and experience, which is imprecise and difficult for beginners. To accurately assess the flexion-extension gap balance of UKA, we developed a wireless sensor combination consisting of a metal base, a pressure sensor, and a cushion block. After osteotomy, the insertion of a wireless sensor combination allows the real-time measurement of intra-articular pressure. It accurately quantifies the flexion-extension gap balance parameters to guide further femur grinding and tibia osteotomy, to improve the accuracy of gap balance. We conducted an in vitro experiment with the wireless sensor combination. the results showed that there was a difference of 11.3 N after applying the traditional method of flexion-extension gap balance performed by an experienced expert.

Objective Finding reliable tools to predict alignment change after medial mobile‐bearing unicompartmental knee arthroplasty (UKA) can help surgeons avoid under‐ or over‐correction. This prospective study aimed to investigate whether the parameters related to medial collateral ligament tension on valgus stress radiograph can predict the alignment change of medial mobile‐bearing UKA and establish a prediction model. Methods This study prospectively included the patients undergoing medial mobile‐bearing UKA for knee osteoarthritis from November 2018 and April 2021. Patients took valgus stress radiograph and MRI preoperatively and took full‐length weight‐bearing anterior–posterior radiograph of the lower extremity preoperatively and postoperatively. The medial joint space width (MJSW) on valgus stress radiograph, area of femoral and tibial osteophyte on MRI, medial extrusion distance (MED) of the meniscus on MRI, and the change in hip‐knee‐ankle angle (∆HKAA) were measured. Factors influencing ∆HKAA were analyzed by correlation analysis. Univariable and multivariable linear regression analysis was performed to establish a prediction model of ∆HKAA. Results One hundred and seven knees were included. On average, the preoperative HKAA was 170.84° ± 3.73°, and UKA corrected the alignment to 175.16° ± 3.21° postoperatively (p < 0.001), with ∆HKAA of 4.33° ± 1.93°. Correlation analysis showed that ∆HKAA correlated with MJSW (r = 0.628, p < 0.001), MED (r = 0.262, p < 0.001), and tibial osteophyte area (r = 0.235, p < 0.001). The prediction model for ∆HKAA was obtained by multivariable linear regression: ∆HKAA = −2.003 + 0.947 × MJSW(mm) + 1.838 × total osteophyte area(cm2). Conclusion Valgus stress radiographic MJSW and osteophyte area are correlated to the alignment change of medial mobile‐bearing UKA. The prediction model for HKAA change is: ∆HKAA = −2.003 + 0.947 × MJSW(mm) + 1.838 × total osteophyte area(cm2).

Background The incidence of periprosthetic fractures after total knee arthroplasty (TKA) increases in parallel with the number of procedures. Comminuted fractures along the primary fracture line extending to the edge of the prosthesis are challenging, and bilateral fractures are rarely reported, especially with open injuries. Case presentation A 65-year-old female had undergone bilateral TKA in our hospital 5 years before admission. She was admitted with a traumatic bilateral Rorabeck type II B distal femur periprosthetic fracture (closed right, open left, Gustilo II) and was treated with bilateral staged open reduction and internal fixation (ORIF) with double-locking plates. The patient experienced a prolonged delayed fracture union and finally healed around 21 months postoperatively. The function was satisfactory after 4 years of follow-up. Conclusion ORIF with double-locking plates can be used to treat Rorabeck II B periprosthetic fracture where the primary fracture line extends beyond the edge of the prosthesis; however, there may be delayed healing or nonunion. Patients need to undergo long-term rehabilitation and endure long disability times and require good rehabilitation nursing care. Once they achieve bone healing, the treatment achieves bone preservation and substantial prosthesis survival.

Objective:To trace the outcomes of motor function rehabilitation in one year after unicompartmental knee arthroplasty,and to find out the dysfunction that may hinder rapid rehabilitation.Method:A total of 243 patients with 256 knees who underwent unicompartmental knee arthroplasty for the first time under the integrated mode of orthopaedic rehabilitation in Xuanwu Hospital from January 2016 to August 2019 were retrospectively enrolled.Age,gender,operation time,time of follow-up,HSS-KS ＆WOMAC score at preoperation/1-month after operation/3-month after operation/6-month after operation/12-month after operation were collected.The subitem of muscle strength,range of motion,flexion deformity,functional activities,pain,stiffness,functional difficulty were primarily focused on.Repeated measurement ANOVA was used to compare the rehabilitation outcome of motor function before and within 12 months after operation.Result:The number of patients followed up at 3 months,6 months and 12 months were 94,60 and 39.HSS-KS total score had a decreasing trend after surgery,activity and functional score decreased significantly after surgery,and the three continued to increase from 1 to 6 months after surgery.Muscle strength score showed a decreasing trend after operation,and recovered to the preoperative level 1 month after operation.Stiffness score showed a decreasing trend after operation,and decreased significantly 1 month after operation,while flexion deformity score increased significantly after operation.There was no significant difference in the total WOMAC score before and after surgery,the pain score decreased significantly after surgery,and the mobility difficulty score increased significantly after surgery.The three scores continued to decrease from 1 to 6months after surgery,and there were no significant differences in all the indicators 1 year after surgery compared with 6 months after surgery.Conclusion:The function of knee joint after single condyle replacement showed an overall improvement trend within 6 months,but no significant improvement was observed from 6 months to 12 months after operation.How to improve functional activities faster needs to be attended.

Unicompartmental knee arthroplasty (UKA) is an effective treatment for end-stage anteromedial osteoarthritis (AMOA). The key to UKA is the flexion-extension gap balance, which is closely related to postoperative complications such as bearing dislocation, bearing wear, and arthritis progression. The traditional gap balance assessment is performed by indirectly sensing the tension of the medial collateral ligament by a gap gauge. It relies on the surgeon's feel and experience, which is imprecise and difficult for beginners. To accurately assess the flexion-extension gap balance of UKA, we developed a wireless sensor combination consisting of a metal base, a pressure sensor, and a cushion block. After osteotomy, the insertion of a wireless sensor combination allows the real-time measurement of intra-articular pressure. It accurately quantifies the flexion-extension gap balance parameters to guide further femur grinding and tibia osteotomy, to improve the accuracy of gap balance. We conducted an in vitro experiment with the wireless sensor combination. the results showed that there was a difference of 11.3 N after applying the traditional method of flexion-extension gap balance performed by an experienced expert.