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Ethics approval and study design
This study was conducted in accordance with the institutional requirements for human-subject research and was approved by the Institutional Ethics Committee of Ganzhou People's Hospital (approval No. 2025-GPH-326-23). Written informed consent was obtained from all participants before enrollment. This was a single-center prospective cohort study. Patients in the intervention and control groups were enrolled concurrently, and the structured nursing pathway was introduced into routine clinical practice in 2025. Group classification was determined by the postoperative nursing pathway actually received and was completed before outcome assessment.
Study subjects
Patients with anterior cruciate ligament (ACL) injuries who underwent arthroscopic ACL reconstruction at our hospital between October 2024 and August 2025 were included in this study. We established the following inclusion criteria for study enrollment: isolated moderate-to-severe ACL injury confirmed by clinical symptoms, physical examination, and knee magnetic resonance imaging (MRI); age ranging from 18 to 45 years; primary (first-time) arthroscopic ACL reconstruction using an autologous hamstring tendon graft; preoperative Lysholm knee function score < 60 points9; and the ability to complete all scheduled follow-up assessments, with written informed consent provided. Our exclusion criteria were: comorbid structural knee injuries (e.g., meniscal tear, collateral ligament injury); severe cardiac, hepatic, or renal dysfunction; coagulation disorders or active infection; prior history of knee surgery or major knee trauma; cognitive impairment or psychiatric disorders; and inability to cooperate with the study intervention or follow-up protocols. Patients were considered to have an isolated ACL injury only when preoperative MRI and intraoperative arthroscopic inspection showed no meniscal tear requiring suture or partial meniscectomy, no collateral ligament injury requiring surgical treatment, and no indication for a lateral extra-articular procedure.
Sample size estimation
We calculated the required sample size for this study using statistical software. Drawing on relevant published research findings10, we set the two-sided alpha level (α) at 0.05, beta level (β) at 0.10, and anticipated effect size (d) at 0.8. Based on these parameters, a minimum of 42 participants per group was required to detect a clinically meaningful difference between the two groups. We factored in an estimated 10% loss to follow-up by modestly increasing the target sample size and ultimately enrolled 93 patients. This was a single-center cohort study rather than a randomized trial. Eligible patients were screened according to the same inclusion and exclusion criteria before group classification. Patients were grouped according to the postoperative nursing pathway actually received in routine clinical practice: those managed with the structured systematic nursing program were included in the intervention group, whereas those managed with standard routine orthopedic nursing were included in the control group. Group classification was completed before postoperative outcome assessment and was not based on postoperative recovery status, complication occurrence, or biomarker results. To reduce clinical heterogeneity, all patients underwent primary arthroscopic ACL reconstruction using an autologous hamstring tendon graft, all procedures were performed by the same orthopedic team, and the same assessment schedule was applied to both groups. All enrolled patients completed the entire intervention period and all scheduled follow-up evaluations. The baseline demographic and clinical characteristics were similar between the two groups, with no statistically significant differences observed (P > 0.05; Table 1).
Surgical method
All surgeries were carried out arthroscopically by the same orthopedic surgical team. An autologous hamstring tendon graft was used for reconstruction in every patient. After a routine arthroscopic inspection, damaged tissue was debrided, and the graft was prepared. No patient in either group underwent concomitant meniscal suture, partial meniscectomy, or lateral extra-articular tenodesis/procedure; therefore, these operative adjuncts were identical between the intervention and control groups. Bone tunnels were then positioned and drilled, followed by graft placement and fixation. A surgical drain was inserted according to standard practice. The incision was then closed, followed by the application of an elastic compression dressing.
Nursing methods
Patients in the control group received standard postoperative orthopedic nursing. Vital signs were monitored regularly, and the incision was checked for bleeding or seepage. Drain output was recorded, and the tube was managed in accordance with routine ward practice. Dressings were changed on schedule, with attention to signs of local infection. Basic education was provided on postoperative precautions, diet, and the main points of early rehabilitation. Pain relief was managed as usual, with analgesics administered when patients reported discomfort. Nurses assisted with turning, positioning, and early limb movement to reduce the risk of pressure injury and venous thrombosis. Before discharge, patients received the standard instructions, including their follow-up appointments and key points to watch for at home.
In addition to the routine care described above, patients in the intervention group received a structured program comprising preoperative assessment and preparation, intraoperative coordination, a 1-month systematic postoperative intervention, and short-term follow-up. The program was implemented by an orthopedic nursing team using an individualized checklist based on each patient’s functional status, pain level, psychological state, and rehabilitation tolerance.
Before surgery, nurses assessed knee pain, swelling, range of motion, quadriceps activation, gait and weight-bearing ability, skin condition, thromboembolic risk, and anxiety or depressive symptoms. Based on these findings, patients received individualized education on the surgical process, brace and crutch use, limb elevation, cold compression, wound protection, expected postoperative pain, warning signs, and the main precautions during early rehabilitation. Bedside preoperative training included ankle-pump exercises, quadriceps isometric contraction, preparation for straight-leg raising, and safe transfer practice within the range allowed by the surgeon.
During surgery, nurses verified the patient’s identity, the injured side, the graft plan, and the individualized nursing plan with the surgical team. They assisted with positioning and padding, maintained sterile instrument preparation, observed limb perfusion and pressure points, and coordinated drain placement, compression dressing, and postoperative handover. The handover emphasized the reconstructed side, the drain status, the compression dressing, the analgesic plan, early mobilization precautions, and patient-specific risk points.
During the first postoperative month, the intervention was delivered in stages. During postoperative days 1–3, nurses monitored vital signs, wound and drainage status, distal circulation and sensation, pain scores, swelling, and signs of deep venous thrombosis. Limb elevation, intermittent cold therapy, analgesic assessment, ankle-pump exercises, quadriceps isometric exercises, and assisted turning or transfer training were provided. From postoperative day 4 to week 2, the plan focused on wound observation, pain review, progressive range-of-motion exercises, quadriceps activation, patellar mobilization when tolerated, brace and crutch instruction, and gradual weight-bearing per the surgeon’s restrictions. From weeks 3–4, patients received supervised progression of knee flexion training, closed-chain strengthening, gait correction, proprioceptive and balance exercises, and education to avoid premature high-load activity. During hospitalization, rehabilitation instruction and nursing supervision were provided at least once daily. After discharge, patients were contacted twice weekly during the first 2 postoperative weeks and once weekly during weeks 3–411, with additional contact when pain, swelling, wound problems, or difficulty completing exercises occurred. Home exercises were recommended two to three times per day, with each session adjusted according to pain, swelling, wound condition, and surgeon-defined weight-bearing restrictions. Exercise progression was delayed when patients reported increased swelling, wound discomfort, persistent pain, or poor movement control.
Pain management was multimodal and nurse-led. VAS and NRS scores were recorded during nursing contacts, analgesic use was reviewed with the physician when pain interfered with exercise or sleep, and non-pharmacological measures such as cold therapy, positioning, relaxation, and activity adjustment were reinforced. Psychological support included repeated explanation of normal postoperative symptoms, identification of fear-avoidant behavior, encouragement of achievable weekly goals, and referral to the physician when marked anxiety or depressive symptoms were observed. The psychological support component was delivered during preoperative education, inpatient nursing rounds, and each follow-up contact. It focused on expectation-setting, reassurance about normal postoperative symptoms, correction of excessive fear of movement, goal-setting for weekly rehabilitation tasks, and reinforcement of adherence when patients showed reduced motivation or avoidance behavior.
Follow-up was conducted at 2 weeks, 1 month, and 3 months through outpatient visits or telephone contact. Nurses reviewed wound healing, swelling, range of motion, pain scores, exercise adherence, brace and crutch use, and warning symptoms, and adjusted nursing instructions accordingly. For both groups, the formal postoperative nursing intervention period was 1 month.
Observation indicators
The primary outcome was knee function at 1 month after surgery, assessed using the Lysholm Knee Function Scoring Scale. Secondary outcomes included proprioception, knee range of motion, pain scores, serum inflammatory markers, MMP-related indicators, quadriceps muscle strength, psychological status, and postoperative complications. Evaluations were conducted at three time points: 1 day before surgery, 2 weeks postoperatively, and 1 month after surgery. Knee function was scored using the Lysholm Knee Function Scoring Scale12. The scale consists of eight items and yields a total score ranging from 0 to 100, with higher scores indicating better functional status. Range of motion was assessed by measuring knee flexion and extension with a goniometer. Each angle was recorded three times, and the mean value was used. Pain was rated using the visual analog scale (VAS)13 and the numeric rating scale (NRS)14. Proprioception was assessed with the Proprioceptive Function Rating Scale15, which evaluates joint position sense and motor sense.
Fasting venous blood samples were obtained both before and after the intervention. After clotting at room temperature and centrifugation, serum was separated for measurement of IL-6, TNF-α, CRP, MMP-9, MMP-13, and TIMP-1. The ratios of MMP-9 to TIMP-1 and MMP-13 to TIMP-1 were calculated. Quadriceps muscle strength was also assessed. Quadriceps femoris strength was graded with Manual Muscle Testing (MMT)16 on a 0–5 scale, with higher grades indicating stronger muscle strength. Manual muscle testing was selected as a pragmatic bedside measure of early postoperative quadriceps activation. Because the 0-5 manual grading system is less sensitive than dynamometer-based strength testing, quadriceps strength results were interpreted as ordinal rather than precise measures of maximal muscle force. Anxiety and depressive symptoms were assessed using the Self-Rating Anxiety Scale (SAS) and the Self-Rating Depression Scale (SDS)17. Finally, the postoperative complications of the patients were counted. Postoperative complications were recorded during the first postoperative month. Incision infection was defined as redness, swelling, warmth, purulent discharge, or the need for antibiotic treatment after clinical evaluation. Joint swelling was defined as clinically evident knee swelling requiring additional observation, intervention, or delayed progression of rehabilitation. Deep venous thrombosis was diagnosed based on clinical symptoms and confirmed by Doppler ultrasonography when suspected. Graft loosening was assessed clinically and by imaging when indicated. Knee stiffness was defined as restricted knee motion that delayed the planned progression of rehabilitation. The timing, severity, management, and outcome of each complication were recorded.
Statistical methods
Data normality was evaluated with the Shapiro-Wilk test. Continuous variables with a normal distribution are expressed as mean ± standard deviation. Differences between groups were analyzed using independent-samples t-tests, while paired t-tests were used for within-group comparisons between two time points. For comparisons involving multiple time points, repeated-measures analysis of variance (ANOVA) was used. Categorical variables are presented as numbers (percentages) and were analyzed using the chi-square test, whereas ordinal data were compared using the rank-sum test. A two-tailed P value < 0.05 was considered statistically significant. Where appropriate, between-group differences were additionally reported as mean differences (MDs) with 95% confidence intervals (CIs) for continuous outcomes, risk ratios (RRs) or risk differences with 95% CIs for categorical outcomes, and effect sizes including Cohen’s d for normally distributed continuous variables. Exact P values were reported whenever possible instead of only threshold-based P values.