This study aimed to identify any population heterogeneity in factors influencing changes in the HRQoL of patients with KOA that might be used to develop individualised treatment strategies.
We found that patients showed improvement in knee function and HRQoL after TKA, which is consistent with the findings of Zhang et al. (31) and Neuprez et al. (32). The trajectory for EQ-5D-5L indicated that patients experienced a cycle of change in knee function and HRQoL after TKA. HRQoL would be expected to deteriorate for a short period immediately after TKA due to postoperative bed rest, limited knee function, and wound pain. Osteotomy, unicompartmental knee arthroplasty, TKA, and arthroscopic surgery can all improve functional scores in patients with KOA; however, follow-up studies indicate that TKA is better than the other interventions in relieving knee pain and improving knee function in the long term (33). HRQoL is not only an indicator of physical fitness but also a reflection of psychological and socioeconomic status. Therefore, mental well-being may be almost as important as physical discomfort and activity restriction in determining self-reported outcomes and HRQoL after TKA (34, 35). High preoperative expectations are associated with clinical improvement, including pain reduction (36). Maintaining a stable emotional state and a positive attitude toward short-term discomfort are important in patients undergoing TKA. Additionally, patients should follow medical advice strictly and cooperate with examinations, treatment, and rehabilitation exercises. Doctors and rehabilitation therapists should strengthen preoperative communication and psychological counselling for these patients. Appropriate guidance and care are essential to gain the full trust of patients with KOA and boost their confidence, which is essential to the success of treatment (24).
In this study, the results of 2-class GMM indicate that the higher the baseline knee function score, the more rapid the improvement in knee function and HRQoL after surgery. This finding suggests that patients with better knee function at baseline would derive the most benefit from surgery, which is consistent with the findings of Fortin et al. (37). Age-related neuromotor changes lead to skeletal muscle weakness and reduced power. Muscle strength and power have been reported to decrease by at least 24% in TKA recipients compared with those in controls (38). However, more demanding rehabilitation protocols may help to overcome these deficits. Postoperative rehabilitation following TKA would make a substantial contribution to patient outcomes, including a shorter hospital stay and fewer complications. Early rehabilitation, telerehabilitation, outpatient therapy, and high intensity and high velocity exercise may be beneficial to reduce pain intensity and joint stiffness (38). Therefore, joint rehabilitation training and functional exercises should be initiated under medical supervision as soon as possible in these patients. An improved focus on patient rehabilitation after discharge, including home-based exercise and dietary guidance, may also be needed to maximise the benefits of surgery.
In this study, patients with a monthly family income of < 2000 yuan had less improvement in postoperative knee function and HRQoL than their more affluent counterparts, and this difference was observed over a long period of time. Most patients were over the age of 50 years and those with a monthly family income of < 2000 yuan were mostly agricultural or migrant workers. These individuals generally have less health knowledge, are of lower socioeconomic status, and have relatively poor self-management skills (39). For financial reasons, they are less likely to protect their knees when performing daily activities and are more likely to opt for less expensive drugs, medical consumables, and therapies. Furthermore, they often return to work prematurely without adequate rest and rehabilitation after surgery.
Patients in this study who exercised for approximately 30 min daily had a better outcome than those who did not exercise. An appropriate amount of regular exercise both protects and improves knee function in patients with KOA and accelerates postoperative recovery. However, care must be taken to avoid excessive exercise, which can damage the reconstructed knee.
Pain was also identified to affect the outcome of TKA, which is consistent with previous reports (40, 41). Pain severely affects both mobility and mental well-being in patients with KOA. Therefore, adequate perioperative pain management is important in these patients. A study found that some patients with KOA and mild pain do not ask for pain relief soon enough and miss the opportunity for intervention in the early stage of inflammation (41), which led to worsening of the disease. Pain should be controlled effectively in the early stages of KOA, with consideration of interventions such as physical therapy to avoid progression of acute pain to uncontrollable chronic pain. As soon as KOA is diagnosed, doctors and family members should cooperate to standardise pain management and encourage the patient to undertake exercise as appropriate to help preserve their joint function.
This study had some potential limitations. First, data for 67 patients could not be collected at all five time points; these missing results may have resulted in reporting bias. Second, the size of the stable group in the 2-class GMM was small, meaning that the effects of certain patient factors, such as age, sex, and BMI, might not be well reflected. Third, the effects of TKA were not analysed according to the implantation method used. Therefore, future studies should investigate the impact of the implantation method and rehabilitation protocol used on postoperative HRQoL in patients who undergo TKA.