INTRODUCTION: Postoperative urinary retention (POUR) frequently complicates the course of patients following hip and knee arthroplasty. Intrathecal morphine (ITM) was identified as a significant risk factor for POUR. The objective of this study was to investigate the incidence and risk factors for POUR in fast-track total joint arthroplasty (TJA) under spinal anaesthesia (SA) with ITM. METHODS: We conducted a retrospective study of our institutional joint registry of patients who underwent primary TJA under SA with ITM between October 2017 and May 2021. Preoperative (baseline demographics) and perioperative data were collected. The primary outcome was the incidence of POUR after 8 h or earlier, either due to lack of voiding or according to patient's complaints of bladder distension. Univariate and adjusted analyses were performed to identify predictors of POUR. RESULTS: Sixty-nine patients who underwent total knee arthroplasty (TKA) and 36 patients who underwent total hip arthroplasty (THA) under SA with ITM were included in the study. POUR requiring bladder catheterisation was diagnosed in 21% of patients. Independent predictors of POUR were age over 65 years and male gender. CONCLUSIONS SA with ITM for TJA is associated with high rates of POUR in males older than 65 years of age. Other previously identified risk factors such as intraoperative fluid administration or comorbidities may not be as influential.
Humans ; Retrospective Studies ; Male ; Urinary Retention/epidemiology* ; Arthroplasty, Replacement, Knee/adverse effects* ; Anesthesia, Spinal/adverse effects* ; Female ; Arthroplasty, Replacement, Hip/adverse effects* ; Morphine/adverse effects* ; Aged ; Middle Aged ; Risk Factors ; Postoperative Complications/epidemiology* ; Injections, Spinal ; Incidence ; Analgesics, Opioid/adverse effects* ; Aged, 80 and over

BACKGROUND: The choice of unicompartmental knee arthroplasty (UKA) vs . total knee arthroplasty (TKA) in the surgical treatment of knee osteoarthritis (KOA) remains controversial. This study aimed to perform a systematic review and meta-analysis of randomized controlled trials (RCTs) to compare the clinical results of UKA and TKA for treating unicompartmental KOA. METHODS: PubMed, Embase, and the Cochrane Library were systematically searched for articles published up to January 2, 2023. The literature was rigorously screened to include only RCTs comparing UKA and TKA for unicompartmental KOA. A systematic review and meta-analysis were performed to calculate the mean difference (MD), relative risk (RR), and 95% confidence interval (CI) according to the Cochrane standards. RESULTS: Thirteen publications involving 683 UKAs and 683 TKAs were analyzed. Except for one study with a follow-up period of 15 years, all outcome measures reported were within 5 years of follow-up. Meta-analysis showed better knee recovery (MD: 1.23; 95% CI: 1.01-1.45; P  <0.001), greater knee function (MD: 1.78; 95% CI: 0.34-3.22; P  = 0.020), less pain (MD: 0.75; 95% CI: 0.43-1.06; P  <0.001), and better health status (MD: 3.75; 95% CI: 0.81-6.69; P  = 0.010) after UKA than TKA. However, considering the minimal clinically important difference values for these variables, the findings were not clinically relevant. Moreover, UKA patients had fewer complications (RR: 0.59; 95% CI: 0.45-0.78; P  <0.001) and shorter hospital stays (MD: -0.89; 95% CI: -1.57 to -0.22; P  = 0.009) than did TKA patients. There were no statistically significant differences in terms of postoperative range of movement, revision, failure, operation time, and patient satisfaction. CONCLUSIONS In terms of clinical efficacy, there was no obvious advantage of UKA over TKA in the surgical treatment of knee OA when considering the minimal clinically important difference. The main advantage of UKA over TKA is that it leads to fewer complications and a shorter length of hospital stay. It is ideal to perform prospective studies with longer follow-up periods to fully evaluate the long-term efficacy and safety of the two procedures in the future.
Humans ; Arthroplasty, Replacement, Knee/methods* ; Osteoarthritis, Knee/surgery* ; Randomized Controlled Trials as Topic ; Treatment Outcome

OBJECTIVE: To investigate the effectiveness of digital three-dimensional (3D) printing osteotomy guide plate assisted total knee arthroplasty (TKA) in treatment of knee osteoarthritis (KOA) patients with femoral internal implants. METHODS: The clinical data of 55 KOA patients who met the selection criteria between July 2021 and October 2023 were retrospectively analyzed. Among them, 26 cases combined with femoral implants were treated with digital 3D printing osteotomy guide plate assisted TKA (guide plate group), and 29 cases were treated with conventional TKA (control group). There was no significant difference in gender, age, body mass index, side, Kellgren-Lawrence classification, preoperative visual analogue scale (VAS) score, Hospital for Special Surgery (HSS) knee score, knee range of motion, and other baseline data between the two groups ( P>0.05). The operation time, intraoperative blood loss, incision length, postoperative first ambulation time, surgical complications; VAS score, knee HSS score, knee range of motion before operation, at 1 week and 3 months after operation, and at last follow-up; distal femoral lateral angle, proximal tibial medial angle, hip-knee-ankle angle and other imaging indicators at last follow-up were recorded and compared between the two groups. RESULTS: The operation time, incision length, intraoperative blood loss, and postoperative first ambulation time in the guide plate group were significantly lower than those in the control group ( P<0.05). In the control group, there were 1 case of incision rupture and bleeding and 1 case of lower limb intermuscular venous thrombosis, which was cured after symptomatic treatment. There was no complication such as neurovascular injury, incision infection, or knee prosthesis loosening in both groups. Patients in both groups were followed up 12-26 months, with an average of 16.25 months. The VAS score, HSS score, and knee range of motion improved at each time point after operation in both groups, and further improved with time after operation, the differences were significant ( P<0.05). The above indicators in the guide plate group were significantly better than those in the control group at 1 week and 3 months after operation ( P<0.05), and there was no significant difference between the two groups at last follow-up ( P>0.05). At last follow-up, the distal femoral lateral angle, the proximal tibial medial angle, and the hip-knee-ankle angle in the guide plate group were significantly better than those in the control group ( P<0.05). CONCLUSION The application of digital 3D printing osteotomy guide plate assisted TKA in the treatment of KOA patients with femoral implants can simplify the surgical procedures, overcome limitations of conventional osteotomy guides, reduce surgical trauma, achieve individualized and precise osteotomy, and effectively restore lower limb alignment and knee joint function.
Humans ; Arthroplasty, Replacement, Knee/instrumentation* ; Osteoarthritis, Knee/surgery* ; Osteotomy/instrumentation* ; Male ; Retrospective Studies ; Female ; Printing, Three-Dimensional ; Femur/surgery* ; Middle Aged ; Bone Plates ; Range of Motion, Articular ; Aged ; Treatment Outcome ; Surgery, Computer-Assisted/methods* ; Knee Prosthesis ; Knee Joint/surgery* ; Operative Time

OBJECTIVE: To review the research progress of intelligent remote follow-up modes in the application after hip and knee arthroplasty. METHODS: Extensive literature on this topic published in recent years both domestically and internationally was reviewed, and the application of intelligent remote follow-up modes after hip and knee arthroplasty was summarized and analyzed. RESULTS: The intelligent remote follow-up mode is a novel follow-up method based on network information technology. Patients who undergo hip and knee arthroplasty require long-term follow-up and rehabilitation guidance after operation. Traditional outpatient follow-up is relatively time-consuming and inconvenient for some patients in terms of travel and transportation, which makes the application of intelligent remote follow-up modes increasingly widespread worldwide. The inherent attributes of remote interaction and instant feedback of this mode make it particularly valued in the field of hip and knee arthroplasty. Artificial intelligence (AI)-based voice follow-up systems and virtual clinics have significant advantages in improving follow-up efficiency, reducing human resource costs, and enhancing patient satisfaction. CONCLUSION The existing intelligent follow-up system has formed a standardized protocol in remote follow-up and rehabilitation guidance. However, there are still shortcomings in the formulation of personalized rehabilitation plans and the gerontechnological adaptation of human-computer interaction. In the future, it is necessary to construct a multimodal data fusion platform and establish technical application guidelines for different rehabilitation stages.
Humans ; Arthroplasty, Replacement, Knee/rehabilitation* ; Arthroplasty, Replacement, Hip/rehabilitation* ; Artificial Intelligence ; Follow-Up Studies ; Telemedicine

OBJECTIVE: To investigate the effect of femoral condyle sliding osteotomy (FCSO) on the flexion gap and external rotation of the prosthesis in balancing coronal instability during initial total knee arthroplasty (TKA). METHODS: Between November 2021 and October 2024, FCSO technique was applied to balance the coronal medial and lateral spaces during initial TKA in 3 patients, including medial condyle sliding osteotomy (MCSO) and lateral condyle sliding osteotomy (LCSO). There were 1 male and 2 females with the age of 81, 68, and 68 years old. The affected knee has varus or valgus deformity, with tibia-femoral angles of 169.7°, 203.3°, and 162.2°, respectively. The hip-knee-ankle angle (HKA), range of motion (ROM), knee society scoring system (KSS), and pain visual analogue scale (VAS) score were used to evaluate joint function and pain relief. Based on model bone, the thickness and bone bed area of the medial and lateral femoral condyle osteotomy blocks in FCSO were measured. During TKA in 12 patients, the range of osteotomy block movement was evaluated. By simplifying the upward and forward movement of the osteotomy block into a geometric model, the impact of movement on the flexion gap and external rotation of the prosthesis was calculated. RESULTS: After application of FCSO during TKA, the limb alignment and medial and lateral balance at extension and flexion positions were restored in 3 patients. Three patients were followed up 23, 11, and 3 months, respectively. Postoperative HKA, pain VAS score, KSS score, and ROM all showed significant improvement compared to preoperative levels. The maximum thickness of osteotomy blocks by MCSO and LCSO was 17 and 12 mm, respectively. The simple upward movement of the osteotomy block mainly affected the extension gap, and had little effect on the flexion gap and external rotation of the prosthesis. Moving the osteotomy block forward at the same time had a significant impact on the flexion gap and external rotation of the prosthesis, especially on LCSO. Mild forward movement leaded to a decrease in external rotation of more than 3°, which had a serious impact on the patellar trajectory. CONCLUSION FCSO can effectively solve the problem of imbalance between the medial and lateral spaces during initial TKA, avoiding knee joint instability caused by excessive loosening and limiting the use of constrained condylar prosthesis. The distance for the downward movement of the osteotomy block in MCSO and LCSO was 3-5 mm and 6-8 mm, respectively, with 10-15 mm of space for forward movement and almost no space for backward movement. For MCSO, the upward and forward movement of the osteotomy block will increase the external rotation of the prosthesis, which is beneficial for improving the patellar trajectory and suitable for valgus knee. LCSO is suitable for varus knee, and the osteotomy block only slides vertically up and down without moving forward and backward.
Humans ; Osteotomy/methods* ; Male ; Female ; Arthroplasty, Replacement, Knee/methods* ; Aged ; Range of Motion, Articular ; Femur/surgery* ; Knee Joint/physiopathology* ; Aged, 80 and over ; Knee Prosthesis ; Treatment Outcome ; Osteoarthritis, Knee/surgery*

OBJECTIVE: To explore the effectiveness of artificial hemi-knee prosthesis reconstruction for bone defects after resection of pediatric osteosarcoma. METHODS: A retrospective analysis was conducted on the clinical data of 18 children with osteosarcoma who met the selection criteria and were treated between January 2016 and December 2019. There were 11 males and 7 females, aged 6-10 years (mean, 8.9 years). Osteosarcoma located in the distal femur in 11 cases and the proximal tibia in 7 cases. Among them, 12 cases were conventional osteosarcoma and 6 cases were small cell osteosarcoma, with a disease duration of 1-9 months (mean, 3.1 months). All patients received 2 cycles of preoperative chemotherapy with doxorubicin, cisplatin, and ifosfamide. After en bloc tumor segment resection, bone defects were reconstructed using custom-made artificial hemi-knee prostheses. Rehabilitation training was initiated at 8 weeks postoperatively under the protection of a knee immobilizer brace, combined with 4 cycles of adjuvant chemotherapy. During follow-up, lower limb growth length and limb shortening (compared with the healthy side) were measured, and limb function was evaluated using the Musculoskeletal Tumor Society-93 (MSTS-93) scoring system. RESULTS: All surgeries were successfully completed, with an operation time of 2.0-3.1 hours (mean, 2.4 hours) and intraoperative blood loss of 180-320 mL (mean, 230.0 mL). Incisional edge necrosis occurred in 1 case at 10 days postoperatively, while the incisions of the remaining 17 patients healed by first intention. One case developed periprosthetic infection caused by Staphylococcus aureus at 1 week postoperatively, which was cured after symptomatic treatment. All 18 patients were followed up 60-96 months (mean, 74.2 months). No local tumor recurrence was observed during follow-up. Imaging examinations showed prosthesis loosening in 2 cases, while the prosthesis of other patients were well-positioned. At last follow-up, the knee joint range of motion was 80°-120° (mean, 106.7°). The MSTS-93 score was 16-29 (mean, 24.7), with 12 cases rated as excellent, 5 good, and 1 fair. The patients' height increased by 12.8-20.0 cm (mean, 15.5 cm), the lower limb growth length was 6.0-13.0 cm (mean, 9.7 cm), and limb shortening was 1.8-4.6 cm (mean, 3.1 cm). There was no significant difference in MSTS-93 scores, lower limb growth length, or limb shortening between the distal femur group and the proximal tibia group ( P>0.05). CONCLUSION Artificial hemi-knee prosthesis reconstruction can preserve the adjacent normal epiphysis of the knee joint, maximize limb growth potential, and reduce adult limb length discrepancy, making it a suitable reconstruction option for children with knee osteosarcoma.
Humans ; Osteosarcoma/surgery* ; Male ; Child ; Female ; Knee Prosthesis ; Retrospective Studies ; Bone Neoplasms/surgery* ; Plastic Surgery Procedures/methods* ; Tibia/surgery* ; Femur/surgery* ; Arthroplasty, Replacement, Knee/methods* ; Treatment Outcome ; Chemotherapy, Adjuvant ; Femoral Neoplasms/surgery*

OBJECTIVE: To investigate the effectiveness and safety of simultaneous bilateral total knee athroplasty (SB-TKA) for the treatment of patients aged 65 years and younger with bilateral knee osteoarthritis (KOA) by comparing with patients undergoing unilateral total knee arthroplasty (U-TKA). METHODS: A clinical data of patients, who underwent primary TKA for KOA and met the selection criteria between June 2019 and July 2023, was retrospectively analyzed, including 181 patients in the U-TKA group and 52 patients in the SB-TKA group. The baseline data of age, gender, disease duration, body mass index, and preoperative hemoglobin (Hb), knee range of motion (ROM), Oxford knee score (OKS), and visual analogue scale (VAS) score for pain were compared between the two groups, with no significant difference ( P>0.05). The operation time, postoperative hospital stay, and all complications related to knee arthroplasty were recorded. Hb was measured at 2 days after operation and the difference between pre- and post-operation was calculated. The knee function and pain were evaluated by using ROM, OKS score, and VAS score and compared between the two groups. RESULTS: The operation time and postoperative hospital stay duration were significantly shorter in the U-TKA group than in the SB-TKA group ( P<0.05). The difference of Hb was significantly lower in the U-TKA group ( P<0.05). All patients were followed up 12-61 months (mean, 37.2 months). There was no significant difference in follow-up time between the two groups ( P>0.05). At last follow-up, the ROM, OKS score, and VAS score of both groups were better than the preoperative ones, and the differences were significant ( P<0.05); there were significant differences between the two groups in the ROM and OKS score ( P<0.05), while no significant difference was found in the VAS score ( P>0.05). Mild complications were observed in 31 cases (17.13%) and severe complications in 3 cases (1.66%) in the U-TKA group, while mild complications were observed in 14 cases (26.92%) in the SB-TKA group, and no severe complication occurred. There was no significant difference in the incidences of mild and severe complications between the two groups ( P>0.05). CONCLUSION In patients aged 65 years and younger with bilateral KOA, knee function and mobility can significantly improved when treated by SB-TKA. While patients had lower postoperative knee mobility and function scores compared with U-TKA, there was no significant difference in pain scores or overall incidence of complication. Strict patient selection and scientific perioperative management are important to achieve good effectiveness after operation in patients with SB-TKA.
Humans ; Arthroplasty, Replacement, Knee/adverse effects* ; Male ; Female ; Retrospective Studies ; Osteoarthritis, Knee/physiopathology* ; Range of Motion, Articular ; Treatment Outcome ; Middle Aged ; Operative Time ; Length of Stay ; Knee Joint/physiopathology* ; Pain Measurement ; Postoperative Complications/epidemiology* ; Aged

OBJECTIVE: To evaluate the analgesic efficacy of ultrasound-guided high fascia iliaca compartment block (HFICB) in managing tourniquet-related pain following total knee arthroplasty (TKA). METHODS: A prospective randomized controlled trial was conducted involving 84 patients with severe knee osteoarthritis or rheumatoid arthritis who underwent unilateral TKA between March 2024 and December 2024. Patients were randomly assigned to two groups ( n=42) using a random number table. In the trial group, ultrasound-guided HFICB was performed preoperatively, with 0.2% ropivacaine injected into the fascia iliaca compartment. No intervention was administered in the control group. Baseline characteristics, including gender, age, surgical side, body mass index, and preoperative visual analogue scale (VAS) scores at rest and during movement, showed no significant difference between the two groups ( P>0.05). In both groups, a tourniquet was applied after osteotomy and before pulsed lavage, and removed after the closure of the first layer of the joint capsule. Postoperative assessments were conducted at 6, 12, 24, and 48 hours, including VAS scores at the tourniquet site (at rest and during movement), Bromage motor block scores, Ramsay sedation scores, and Bruggrmann comfort scale (BCS) scores to evaluate patient comfort. Additionally, the average tramadol consumption and incidence of nausea and vomiting within 48 hours postoperatively were recorded and compared. RESULTS: In the trial group and control group, VAS scores during movement at the tourniquet site significantly improved at all postoperative time points compared to preoperative levels ( P<0.05). VAS scores at rest increased transiently at 6 hours after operation in both groups, and then gradually decreased to the preoperative level. Except that there was no significant difference at 48 hours after operation in the trial group ( P>0.05), there were significant differences at other time points of two groups compared to preoperative score ( P<0.05). Except for VAS score at rest at 6 hours, VAS score during movement at 48 hours, and BCS comfort score at 48 hours ( P>0.05), the trial group showed significantly better outcomes than the control group in terms of VAS score at rest, VAS score during movement, Ramsay sedation scores, and BCS comfort scores at all other time points ( P<0.05). No significant difference was found in Bromage motor block scores between the groups ( P>0.05). Tramadol was used in 3 patients in the trial group and 7 patients in the control group within 48 hours after operation, the dosage was (133.30±14.19) mg and (172.40±22.29) mg, showing significant difference ( P<0.05). Nausea and vomiting occurred in 4 patients (9.5%) in the trial group and 3 patients (7.1%) in the control group, with no significant difference in incidence between groups ( P>0.05). CONCLUSION Ultrasound-guided HFICB provides effective analgesia for tourniquet-related pain following TKA, facilitates early postoperative functional recovery of the knee joint, and may serve as a valuable clinical option for postoperative pain management in TKA patients.
Humans ; Arthroplasty, Replacement, Knee/adverse effects* ; Nerve Block/methods* ; Male ; Female ; Pain, Postoperative/etiology* ; Tourniquets/adverse effects* ; Prospective Studies ; Middle Aged ; Ropivacaine/administration & dosage* ; Aged ; Ultrasonography, Interventional ; Anesthetics, Local/administration & dosage* ; Pain Measurement ; Fascia ; Osteoarthritis, Knee/surgery* ; Treatment Outcome ; Arthritis, Rheumatoid/surgery*

OBJECTIVE: To investigate the diagnostic efficacy of ^99mTc-MDP three-phase bone scintigraphy (TPBS) combined with C-reactive protein (CRP) for periprosthetic joint infection (PJI). METHODS: The clinical data of 198 patients who underwent revision surgery of artificial joint between January 2017 and January 2024 and received TPBS examination before surgery were retrospectively analyzed. There were 77 males and 121 females with an average age of 63.74 years ranging from 24 to 92 years. There were 90 cases of hip arthroplasty and 108 cases of knee arthroplasty. PJI was diagnosed according to the 2013 American Musculoskeletal Infection Society (MSIS) standard diagnostic criteria. The sensitivity, specificity, accuracy, negative predictive value (NPV), and positive predict value (PPV) were calculated. The receiver operating characteristic (ROC) curve was used to compare the diagnostic performance of the three methods, and the area under curve (AUC) was used to evaluate the diagnostic performance. RESULTS: According to the 2013 MSIS criteria, 116 cases were diagnosed as PJI, and the remaining 82 cases were aseptic loosening. The cases of PJI diagnosed by TPBS, CRP, and TPBS-CRP were 125, 109, and 137 respectively, and the cases of aseptic loosening were 73, 89, and 61 respectively. The sensitivity, accuracy, NPV, and PPV of TPBS-CRP combination in the diagnosis of PJI were higher than those of TPBS and CRP, but the specificity was lower than that of TPBS and CRP. ROC curve analysis further showed that the AUC value of TPBS-CRP combination was better than that of TPBS and CRP. The severity of bone defect and the duration of symptoms in patients with false positive TPBS diagnosis were worse than those in patients with true negative TPBS diagnosis (P<0.05), but there was no significant difference in the survival time of prosthesis between the two groups (P>0.05). Among the patients diagnosed with PJI by TPBS, CRP, and TPBS-CRP, 49, 35, and 54 patients had received antibiotic treatment 2 weeks before diagnosis, respectively. There was no significant difference in the diagnostic accuracy of TPBS and TPBS-CRP before diagnosis between patients treated with and without antibiotics and those not treated (P>0.05). The diagnostic accuracy of antibiotic therapy before CRP diagnosis was significantly lower than that of untreated patients (P<0.05). CONCLUSION TPBS and CRP have limited specificity in differentiating PJI from aseptic loosening. The TPBS-CRP combination diagnostic method can synergize the local bone metabolic characteristics and systemic inflammatory response to achieve higher diagnostic accuracy, but caution should be exercised in patients with severe bone defects and longer symptom duration.
Humans ; Prosthesis-Related Infections/blood* ; Middle Aged ; Male ; Female ; Aged ; C-Reactive Protein/metabolism* ; Retrospective Studies ; Adult ; Radionuclide Imaging/methods* ; Arthroplasty, Replacement, Knee/adverse effects* ; Aged, 80 and over ; Technetium Tc 99m Medronate ; Arthroplasty, Replacement, Hip/adverse effects* ; Sensitivity and Specificity ; Knee Prosthesis/adverse effects* ; ROC Curve ; Reoperation ; Radiopharmaceuticals ; Young Adult

OBJECTIVE: To explore, identify, and develop novel blood-based indicators using machine learning algorithms for accurate preoperative assessment and effective prediction of postoperative complication risks in patients with rheumatoid arthritis (RA) undergoing total knee arthroplasty (TKA). METHODS: A retrospective cohort study was conducted including RA patients who underwent unilateral TKA between January 2019 and December 2024. Inpatient and 30-day postoperative outpatient follow-up data were collected. Six machine learning algorithms, including decision tree, random forest, logistic regression, support vector machine, extreme gradient boosting, and light gradient boosting machine, were used to construct predictive models. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC), F1-score, accuracy, precision, and recall. SHapley Additive exPlanations (SHAP) values were employed to interpret and rank the importance of individual variables. RESULTS: According to the inclusion criteria, a total of 1 548 patients were enrolled. Ultimately, 18 preoperative indicators were identified as effective predictive features, and 8 postoperative complications were defined as prediction labels for inclusion in the study. Within 30 days after surgery, 453 patients (29.2%) developed one or more complications. Considering overall accuracy, precision, recall, and F1-score, the random forest model [AUC=0.930, 95% CI (0.910, 0.950)] and the extreme gradient boosting model [AUC=0.909, 95% CI (0.880, 0.938)] demonstrated the best predictive performance. SHAP analysis revealed that anti-cyclic citrullinated peptide antibody, C-reactive protein, rheumatoid factor, interleukin-6, body mass index, age, and smoking status made significant contributions to the overall prediction of postoperative complications. CONCLUSION Machine learning-based models enable accurate prediction of postoperative complication risks among RA patients undergoing TKA. Inflammatory and immune-related blood biomarkers, such as anti-cyclic citrullinated peptide antibody, C-reactive protein, and rheumatoid factor, interleukin-6, play key predictive roles, highlighting their potential value in perioperative risk stratification and individualized management.
Humans ; Arthroplasty, Replacement, Knee/adverse effects* ; Arthritis, Rheumatoid/blood* ; Machine Learning ; Postoperative Complications/blood* ; Female ; Male ; Retrospective Studies ; Middle Aged ; Aged ; Risk Factors ; Preoperative Period ; C-Reactive Protein/analysis* ; Risk Assessment