With the accelerating global population aging, the prevalence of joint diseases such as osteoarthritis has risen markedly, driving an increasing demand for hip and knee arthroplasty. However, surgical outcomes are influenced by multiple factors, including underlying comorbidities of patients (e.g., hypertension and diabetes), surgical techniques, and prosthesis selection. The complexity of comorbidities in elderly patients further amplifies surgical risks and technical challenges. Intraoperative and postoperative hemorrhage remains a pivotal challenge in hip and knee arthroplasty. Elderly patients and those with comorbidities often experience hidden blood loss and elevated transfusion requirements, predisposing them to complications such as infections and transfusion-related adverse events. Although existing guidelines emphasize perioperative blood management, systematic guidance on intraoperative hemostatic strategies remains insufficient. Therefore, there is an urgent need to advance research and standardize intraoperative hemostatic protocols to reduce blood loss,minimize transfusion-associated risks, optimize blood resource utilization, enhance postoperative recovery, and alleviate healthcare system burdens. To address these issues, the consensus expert panel formulated evidencebased recommendations through evidence grading and multidisciplinary discussions, establishing a standardized reference framework for surgical hemostasis. This consensus underscores the necessity of individualized clinical implementation, advocating flexible adaptation based on real-world practice.
To analyze the information related to hip and knee arthroplasty in a hospital affiliated to a medical university in the past 12 years, and take this as an example to reflect the surgical trend and health economic trend of joint arthroplasty in the past decade.
Methods
The data of patients undergoing hip and knee replacement in a hospital affiliated to a medical university from 2011 to 2022 were collected and analyzed, including patients’ age, gender, length of hospital stay, main diagnosis, name of operation, treatment cost, etc., and the changes in the number of operations, age composition of patients, gender differences, length of stay and treatment costs were compared. Statistical results were analyzed by t test and logistic regression analysis.
Results
A total of 13 993 cases of hip and knee arthroplasty were studied in this study, including 8 232 cases of hip arthroplasty and 5 761 cases of knee arthroplasty. In the hip arthroplasty related operations, the annul number of hip arthroplasty cases increased by an average of 9.9%, the average age of patients was (68±13)years, male patients accounted for 42.2% and female patients accounted for 57.8%. The average length of hospital stay of patients decreased by 46.7% compared with 2011. The average cost of total treatment was 53 936 yuan, of which the cost of consumables accounted for 59.2%. Total costs were 15.9% lower than the data in 2011. The annual number of knee surgery cases in the hospital increased by an average of 10.0% year by year, the average age of patients was (70±8) years, the proportion of male patients was 30.4%, and the proportion of female patients was 69.6%. The average length of hospital stay of patients was reduced by 41.5% compared with 2013, and the average total treatment cost was 48 559 yuan, of which consumables accounted for 56.3%. The total cost was 29.6% lower than in 2013.
Conclusions
The number of patients undergoing hip and knee replacement is increasing year by year. Although the hospitalization days and hospitalization costs of patients are significantly reduced compared with previous years, patients still have a large burden of treatment costs. Reducing the cost of surgical consumables is an important link to reduce the total cost.
To explore the application effect of medical imaging three dimensional(3D)reconstruction technology in patients undergoing total hip arthroplasty.
Methods
Seventy-two patients who underwent total hip arthroplasty in the department of orthopedics, First Affiliated Hospital of Guangzhou Medical University from January 2020 to December 2023 were enrolled. Among the enrolled patients, the patients from January 2021 to June 2022 were selected as the control group and the patients from July 2022 to December 2023 were the observation group. Inclusion criteria: patients were diagnosed as hip dysplasia and met the surgical indications for total hip arthroplasty; primary total hip arthroplasty; age≥18 years; normal communication and comprehension ability; complete research data. Exclusion criteria: abnormal coagulation function; diseases of important organs; intolerance to total hip arthroplasty; co-existing infectious diseases and malignant tumors;poor compliance. The control group underwent conventional total hip arthroplasty, and the observation group underwent artificial total hip arthroplasty based on medical imaging 3D reconstruction technology. The visual analogue scale (VAS), hip Harris score, imaging indexes before and one week after surgery and surgical indices were compared between the two groups by t test.
Results
VAS score of the observation group was lower than that of the control group at three months after surgery (t=3.242, P<0.05). The Harris score of hip joint in the observation group was higher than that in the control group at three months after surgery (t=4.708, P<0.05).The anterior and abduction angles in the observation group were lower than those in the control group after one week of surgery (t=6.197, 4.688, both P<0.05). The intraoperative blood loss and operation time of the observation group were lower than those of the control group (t=4.510, 5.732, both P<0.05).
Conclusion
The use of medical imaging 3D reconstruction and technology in patients undergoing total hip arthroplasty can improve the surgical quality, relieve pain and improve hip joint function.
To investigate the relationship between preoperative coronal alignment and postoperative alignment following Oxford unicompartmental knee arthroplasty (UKA), and to explore methods for predicting postoperative alignment.
Methods
This retrospective study enrolled 130 patients (156 knees) who underwent Oxford mobile-bearing UKA for anteromedial knee osteoarthritis at the Second Hospital of Shanxi Medical University between January 2021 and December 2022. Patients with incomplete imaging data or a history of trauma or fractures were excluded. Based on postoperative hip-knee-ankle (HKA) angles, the patients were categorized into three groups: neutral alignment group (-1°≤HKA<3°, n=68), moderate varus group (3°≤HKA≤7°, n=74), and excessive varus group (HKA>7°, n=14). Imaging data of the patients were retrospective analyzed for the intergroup differences in preoperative HKA (pre-HKA), lateral distal femoral angle (LDFA),medial proximal tibial angle (MPTA), and arithmetic HKA (aHKA) using the Kruskal-Wallis H test. Spearman correlation analysis was performed to identify associations between preoperative parameters and postoperative alignment.
Results
Statistically significant differences were observed among the three groups in pre-HKA(H=51.836, P<0.001), MPTA (H=39.764, P<0.001), LDFA (H=31.401, P<0.001), and aHKA (H=81.992,P<0.001). Spearman analysis revealed the strongest correlation between aHKA and postoperative HKA (r=-0.805,P<0.001), with the regression equation: post-HKA=-0.7×aHKA+0.5.
Conclusions
Preoperative coronal alignment significantly influences postoperative alignment in Oxford UKA. aHKA serves as a reliable predictor of postoperative HKA. Caution is warranted when aHKA approaches or exceeds 2.1°(risk of valgus alignment)or falls below -9.3° (risk of excessive postoperative varus deformity).
To compare and analyze the clinical efficacy of the treatment of acute anterior cruciate ligament (ACL) rupture by single-bundle reconstruction among with suspension remnant-preserving,sleeve remnant-preserving,and non-remnant-preserving under arthroscopic.
Methods
A retrospective analysis was conducted on clinical data from 125 patients undergoing arthroscopic autograft single-bundle reconstruction for ACL rupture in the Department of Orthopedics and Sports Medicine between January 2020 and June 2022. Inclusion criteria: age were 16 to 50 years; all the patients underwent surgery within three weeks after injury; MRI confirmed complete disruption of continuity and integrity of ACL; patients had high demands for functional recovery of the knee joint. Exclusion criteria: patients with concomitant bone fractures,collateral ligament injuries, or other autoimmune joint diseases. There were 87 males and 38 females among the enrolled patients. Based on surgical techniques, patients were stratified into three groups: suspension group using suspension remnant-preserving reconstruction (n=43), sleeve group adopting sleeve remnantpreserving reconstruction (n=41), and debridement group adopting non-remnant-preserving reconstruction with debridement (n=41). All three groups underwent identical postoperative functional rehabilitation protocols. Clinical efficacy was comprehensively assessed by comparing operative duration, Lysholmscores and International Knee Documentation Committee (IKDC) knee function scores preoperatively and at six, 12 months postoperatively, KT-2000 arthrometer measurements for knee stability, threshold to detect passive motion (tTDPM) for proprioception assessment, and regular postoperative MRI examinations of the affected knee. Statistical analyses included one-way analysis of variance (ANOVA) and chi square tests.
Results
All the patients in this study completed follow-up ranging from 12 to 36 months, (17.5±2.4) months on average. The sleeve group exhibited seven cases of complications, including cyclops lesion, comma sign, or hyperextension impingement, whereas no such complications were observed in the suspension group or debridement group.Operative durations were compared among three groups, with no statistically significant differences (F=0.257,P>0.05). At six months after surgery, the suspension group demonstrated the highest Lysholm scores (84.5±3.3)and IKDC scores (81.1±2.9) , followed by the sleeve group［Lysholm score (82.1±3.0), IKDC (79.6±3.2)］and debridement group［Lysholm score (80.6±4.1), IKDC (78.0±3.7)］, with statistically significant differences among the three groups (F=1.427, 2.502, both P<0.05). KT-2000 arthrometer measurements revealed the lowest side-to-side anterior laxity in the suspension group (2.18 ± 0.24 mm), significantly lower than the sleeve group (2.25±0.38) mm and debridement group (2.32±0.21) mm (F=5.483, P<0.05). TTDPM assessments showed superior proprioception in the suspension group (3.69±0.31)°, outperforming the sleeve group (4.05±0.42) ° and debridement group (4.37±0.28°) (F=2.912, P<0.05). At 12 months postoperatively,Lysholm scores, IKDC scores, and KT-2000 arthrometer measurements were comparable among the three groups, with no statistically significant differences (P>0.05). TTDPM assessments demonstrated significantly better proprioception in the suspension group (1.79±0.22)°, which was lower than the sleeve group (2.05±0.51)°and debridement group (2.28±0.19)°, showing statistically significant intergroup differences (F=1.887,P<0.05).MRI examinations of theinvovledknees at three, six, and 12 months after surgerydemonstrated wellvisualized tendon grafts with robust structural morphology. At all time points, the suspension group exhibited significantly lower graft signal intensity and signal-to-noise quotient (SNQ) compared to the sleeve group and debridement group.
Conclusions
Arthroscopic autograft single-bundle remnant-preserving reconstruction for ACL rupture facilitates graft-bone healing, ligament remodeling, and proprioceptive recovery, thereby enhancing functional rehabilitation of the affected limb. The suspension remnant-preserving technique restores and maintains tension in residual ligamentous tissues, effectively preventing complications such as cyclops lesion, comma sign, and hyperextension impingement.
To evaluate the clinical outcomes of arthroscopic fixation for avulsion fractures of posterior cruciate ligament (PCL) tibial insertion through three posteromedial approaches.
Methods
A retrospective analysis was conducted on patients treated for PCL tibial avulsion fractures via arthroscopic tripleportal posteromedial approach in Yulin Hospital of the First Affiliated Hospital of Xi’an Jiaotong University between December 2019 and December 2021. Patients with concomitant ligament injuries of the knee were excluded. Fracture healing rate was recorded, and clinical outcomes were assessed using Lysholm score,International Knee Documentation Committee (IKDC) subjective knee form, Hospital for Special Surgery(HSS) knee score, and visual analog scale (VAS) for pain. Scores before operation and two years after operation were compared using paired t test and rank sum test.
Results
A total of eight patients were included. All the fractures achieved union, yielding a 100% healing rate. The posterior drawer test was negative in all cases.One patient reported residual knee pain. The overall satisfaction rate was 87.5%. At two-year follow-up,all clinical scores showed significant improvement compared to baseline: Lysholm score (45±13) vs. (89±8)(t=8.232, P<0.001), IKDC score (37±5) vs. (71±7) (t=10.03, P<0.001), HSS score (34±8 ) vs. (92±4) (t=17.87,P<0.001), and VAS score 6(6, 7) vs. 0(0, 0) (t=2.536, P=0.011). The excellent-to-good rates were 75.0%(6/8) in Lysholm score, 62.5% (5/8) in IKDC score, and 100% (8/8) in HSS score.
Conclusions
Arthroscopic fixation of PCL tibial avulsion fractures via three posteromedial approaches is a minimally invasive, reliable, and effective surgical technique. It ensures solid fixation, promotes early functional recovery, and meets the clinical demands for optimal outcomes in the treatment of PCL tibial avulsion fractures.
To observe the clinical application effect on patients with primary total knee arthroplasty (tKA) receiving different administration routes of tranexamic acid combined with cold compress.
Methods
A total of 148 patients with TKA in Chengdu Nuclear Industry 416 Hospital were enrolled from December 2021 to December 2023. The patients were all adult patients who were treated with primary TKA,and there was no contraindication of tranexamic acid nor important organ lesions or diseases. The patients were divided into four groups according to the stratified randomization method by random number table method,including intravenous group (IV group), intra-articular group (IA group), combined group and oral group, 37 cases in each group. The coagulation indicators, inflammatory indicators, total blood loss volume and drainage volume, pain degree, joint range of motion (ROM) and incidence rates of complications were observed among the four groups after medication.One-way analysis of variance was used for measurement data among multiple groups, and chi square or Fisher exact test was used for enumeration data.
Results
The differences were statistically significant in neutrophil to lymphocyte ratio (nLR), monocyte to lymphocyte ratio (MLR), fibrinogen(FIB) and D-dimer (D-D) among the four groups (F=14.580, 19.180, 4.391, 7.974, all P<0.05). FIB (q=6.808,6.407, 8.810), D-D (q=8.055, 7.048, 10.070), NLR (q=3.963, 3.699, 4.668) and MLR (q=4.978, 4.418,6.637) were significantly lower in the combined group than those in the IV group, IA group and oral group（all P<0.05）. The differences were statistically significantin total blood loss volume and drainage volume among the four groups (F=5.27, 4.959, both P<0.05). Total blood loss volume (q=4.262, 4.060, 5.157) and drainage volume (q=3.095, 4.135, 5.012) were significantly lower in the combined group than those in the IV group, IA group and oral group (all P<0.05). The visual analogue scale scores at three and seven days after surgery and knee ROM at three days after surgery revealed no statistically significant differences among the four groups (all P>0.05), but there was a statistically significant difference in knee ROM at seven days after surgery (F=6.083,P<0.05). The ROM in the combined group at seven days after surgery was significantly higher than that in oral group (q=6.030, P<0.05). The incidence rates of complications exhibited no statistically significant differences among the four groups (P>0.05).
Conclusions
Different administration routes combined with cold compress for TKA patients can help to improve coagulation function, inflammatory response and perioperative blood loss.Intravenous medication combined with intra-articular medication may have certain advantages in improving inflammation, inhibiting FIB and D-D levels and improving knee ROM.
To explore the specific changes in the posterior tibial slope angle (PTSA)of medial and lateral sides after distal tibial tubercle-high tibial osteotomy combined with arthroscopy in the treatment of moderate to severe varus knee osteoarthritis.
Method
A total of 62 patients with moderate to severe varus knee osteoarthritis treated in the Third Affiliated Hospital of Beijing University of Chinese Medicine from November 2022 to December 2023 were retrospectively analyzed. Inclusion criteria: unilateral varus knee osteoarthritis with complete postoperative follow-up data. Exclusion criteria: other surgical treatment of the contralateral knee during follow-up; severe other bone diseases; the operative limb was complicated with secondary injury. All the patients were treated with distal tibial tubercle-high tibial osteotomy combined with arthroscopy. All the patients completed the operation and were followed up. Referring to the tibial posterior cortical line in Brazier measurement method, the posterior slope angle of the medial and lateral tibial plateau and the active flexion range of the knee joint at different time points before and after the operation were measured and evaluated by DIGIMIZER digital software on the lateral X-ray film of the surgical knee joint.Pain visual analogue scale (VAS), Western Ontario and McMaster University osteoarthritis index (WOMAC)and Lysholm score were used to evaluate the knee pain and function at different time points before and after operation. Statistical analysis was performed using repeated measurement analysis of variance.
Results
All 62 patients were followed up for (12.5±0.5) months.The medial PTSA was (9.3±1.4)° before operation, and there was no significant change in the medial PTSA at one month, six and 12 months after operation compared with that before operation (F=0.317, P>0.05). The preoperative lateral PTSA was (8.2±1.4)°, and there was no significant change in the lateral PTSA at one month, six and 12 months after operation when compared with that before operation (F=0.096, P>0.05). The knee active flexion range of motion increased from (97±4)°before operation to (103±4)°, (112±4)°, (117±4)° at one month, six and 12 months after operation, and the knee active flexion range of motion gradually increased compared with that before operation. There were significant differences at each time point (F=314.984, P<0.05). The VAS score, WOMAC score and Lysholm score at one month, six and 12 months after operation were significantly improved compared with those before operation(F=1012.288, 822.45, 673.422, all P<0.05).
Conclusion
The distal tibial tubercle-high tibial osteotomy combined with arthroscopy can relieve the pain of moderate to severe varus knee osteoarthritis, improve the knee joint function, increase the range of motion of the knee joint, and has no significant effect on the medial and lateral posterior tibial slope angle in the short term.
To explore the causal association between immune diseases and artificial joint reoperation using Mendelian randomization analysis.
Methods
Through screening public data from nonoverlapping genome-wide association studies, the exposure factors were inflammatory bowel disease, psoriasis,rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus, and the outcome factors were resurgery for artificial joints. inverse variance weighted (IVW) method was adopted as the main analysis method to evaluate the causal effect in this study. The Mendel randomization-Egger method (MR-Egger), weighted median method, weighted mode model and simple mode were used as supplementary methods, and the sensitivity analysis was carried out.
Results
IVW estimates suggested that psoriasis is a risk factor for reoperation of artificial joints［OR=1.12，95%CI (1.01，1.25), P=0.026］. There was no statistically significant occurrence of inflammatory bowel disease, rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus, or artificial joint reoperation in this study (all P>0.05).
Conclusion
There is a causal association between psoriasis and artificial joint reoperation that may increase the risk of artificial joint reoperation.
Gout is an autoinflammatory disease characterized by acute or chronic inflammation and osteoarticular damage due to precipitation of monosodium urate crystals. Recent studies have shown that a variety of immune cells such as macrophages and T lymphocytes play a key role in the occurrence,development and reversal of gout in the pathogenesis of gout, and some inflammatory cytokines, such as those in the interleukin-1 family, have been shown to play anti-inflammatory or proinflammatory roles in gouty inflammation, but the specific mechanism is unknown. This article aimed to start from the role of immune cells and inflammatory factors in the occurrence and development of gout, and provide new ideas for further elucidating the pathogenesis of gout.
Cuproptosis is a novel form of cell death, in which excessive intracellular copper induces the aggregation of lipoylated dihydrolipoic acid-acetyl transferase(DLAT)associated with the mitochondrial tricarboxylic acid (tCA) cycle, resulting in proteotoxic stress. It plays a crucial role in the death of chondrocytes in osteoarthritis, and this view has been confirmed in relevant studies. Research on the mechanism of chondrocyte cuproptosis has revealed that there are four key nodes in cuproptosis. Cuproptosis is closely related to copper accumulation within chondrocytes and changes in mitochondrial function, and is regulated by relevant genes and the immune system. Studies on the intervention of chondrocyte cuproptosis have found that copperrelated compounds, HPP@Cu gel, and the interference of endoplasmic reticulum stress are all targeted therapies for cuproptosis in osteoarthritis.
Based on the application of computer simulation technology in the research of artificial knee joint prostheses, this article reviews and introduces the computer software used in the research of artificial knee joint prostheses, and looks forward to its application prospects. The article will focus on introducing the computer software used in each step of the research on artificial knee joint prostheses, introducing the functions,characteristics, and applications of each software, in order to have a preliminary understanding of computer software.This article reviewed and looked forward to the application of computer software in the research of artificial knee joint prostheses, in order to provide more accurate and intelligent computer software for the computer simulation research of artificial knee joint prostheses.
Cement fixation is considered the gold standard for total knee arthroplasty (tKA), in recent years, however, there has been a shift toward younger and heavier body weight populations, lifelong use of implants is a concern, cementless prostheses can achieve permanent biological fixation with bone, it can preserve bone mass and avoid the production of cement debris, reducing the occurrence of postoperative radiolucent lines. However, it is necessary to restrict weight bearing and high flexion activity in the early postoperative period, which is very unfavorable to the early rehabilitation of patients. In general, both bone cement and cementless prostheses have achieved good results in modern times, but both have certain shortcomings, and hybrid prostheses may improve the survival rate.
Early mobilization after total knee arthroplasty is a central aspect of ERAS,and there are many factors that affect early mobilization. The safety of early mobilization is a top priority, and preventing falls is of utmost importance. This article reviewed the research progresses on influencing factors including general conditions, nutrition, pre-rehabilitation, postoperative pain management, surgical approach, prosthesis type,tourniquet usage, and quadriceps muscle strength on early postoperative mobilization, for clinical practice reference. The ＂cocktail＂ injection of long-acting analgesics such as ropivacaine or bupivacaine liposomes intraoperatively can provide long-lasting postoperative pain relief without affecting the function of the quadriceps muscle, which is more helpful for early mobilization. Surgeons shall try not using tourniquets during surgery or using tourniquets for a short period of time to avoid negative effects on early mobilization. The impact of quadriceps muscle strength, application of tranexamic acid, and intelligent assistive technologies such as robots, navigation on early postoperative mobilization needs further research.
In recent years, with the deeper understanding of the structure of the tibial plateau and the in-depth study of the injury mechanism, the treatment standards for tibial plateau fracture are improving day by day, and the technology is constantly updated. In the treatment of tibial plateau fracture, arthroscopy has shown many advantages, such as small trauma, easy to deal with the accompanying injury and rapid recovery,so it has been rapidly developed and gradually become an important means to treat tibial plateau fracture.This method can more accurately evaluate the reduction of the articular surface of the tibial plateau through direct visual field monitoring under arthroscopy, and is convenient to deal with the accompanying meniscus injury and other problems at the same time. It has the advantages of less trauma and quick recovery, and the clinical effect is positive and the satisfaction is high. However, due to the difficulty of operation and the risk of osteofascial compartment syndrome, this procedure still requires caution, especially for doctors who are not skilled in arthroscopic operation. This article focused on the arthroscopic treatment of tibial plateau fracture in the selection of indications, surgical methods and techniques, clinical efficacy, complications and so on several aspects of review.
To investigate the effectiveness of an improved beach chair position in shoulder joint surgeries.
Methods
Thirty-four patients undergoing grade III and IV shoulder surgeries in the Department of Anesthesia and Surgery of the First Affiliated Hospital of Guangzhou Medical University from January 2023 to June 2024 and placed in the beach chair position were selected as the research objects.Paired sample t test or Wilcoxon signed-rank test was employed for the comparison of the observation indicators before and after the position placement.
Results
All 34 patients successfully completed their surgeries without complications. There was no significant difference in hemoglobin level, oxygen saturation, or incidence of acquired pressure injuries before and after surgery. During surgery, the blood loss was 20(9, 23) ml, and the urine volume was 250(0, 825) ml, fluid intake was (1 265±699) ml, and the surgical duration was (105±69)min. No patient encountered position compression, nerve injury, or lower limb venous thrombosis. Among the patients, 13 underwent invasive arterial blood pressure monitoring during surgery.
Conclusion
The improved“beach chair” position effectively ensures optimal exposure of the surgical field with stable physiological parameters while minimizing the risks of hypotension, nerve and pressure injuries, without postoperative complications, which providing a useful reference for nursing protocols in similar surgeries.
To investigate the incidence and risk factors of postoperative deep vein thrombosis (DVT) in patients undergoing arthroscopic surgery, providing reliable clinical reference for the prevention and follow-up time of DVT after arthroscopy.
Methods
A prospective cohort study was conducted to compare the early and long-term occurrence of DVT in lower limbs of patients after arthroscopy in Jinjiang Hospital from January first to December 31, 2023, by analyzing their general data, relevant laboratory indicators,and postoperative DVT ultrasound follow-up results; The patients with DVT demonstrated by preoperative ultrasound were excluded. According to the time point of postoperative DVT, the patients were divided into early DVT group and forward DVT group. Independent sample t test was used for quantitative data, and chi square test was used for count data to identify statistically significant risk factors between the two groups and explore the risk factors that cause early and forward DVT in patients after arthroscopy surgery.
Results
A total of 171 patients were included in this study, including 13 cases (7.6%) with early DVT: 10 cases of calf intermuscular vein, one case of tibial vein combined with calf intermuscular vein, one case of fibular vein, and one case of great saphenous vein combined with calf intermuscular vein in the thigh segment. Among them, 14 cases (8.1%)experienced forward DVT: 10 cases of calf intermuscular vein, one case of fibular vein, two cases of fibular vein combined with calf intermuscular vein, and one case of posterior tibial vein combined with fibular vein and calf intermuscular vein. Compared with the early DVT group, the time difference of thrombus absorption was statistically significant (χ2=-2.816, P<0.01).
Conclusion
Late DVT after arthroscopy has a certain incidence rate with longer absorption time of the thrombus, and seriously consideration should be taken by clinical doctors.
