After 12 months follow-up assessment, our study observed good outcomes at first month in the patients who took knee flexion enhanced home exercise program. Group KFEH had better ROM range at 1 month than group SPT (P < 0.01). No inferiority was shown about the value of WOMAC, KSS and VAS between two groups as well as complication incidence rate. Not surprisingly, present study showed that home program would lower patients’ times and economic burden.
Total knee arthroplasty is an effective treatment for end stage arthritis, relieving millions of patients suffering arthritis and improving the quality of life . With the process of ageing society, the number of patients undertook TKA surgery has been increased throughout the world in recent years [21, 22]. Helping patients return to their pre-disease conditions and improve quality of life is the meaning of this surgery. Besides excellent surgeon’s operation, postoperative rehabilitation is considered to have much affection about patients' knees function and satisfaction towards surgeries [23, 24]. Faced with high cost of physiotherapy, an effective home program protocol needs to expand in China. By chance, we observed that a crowed of patients who had habitat of sitting small low stools gained fast rehabilitation and better satisfaction after TKA surgery. We hypothesize that sitting low stool could improve ROM especially knee flexion and help patients get faster and better rehabilitation after TKA surgery. Just as some studies demonstrated that the increasing ROM is important for patients' functional outcome and satisfaction after TKA [25, 26].
Knee ROM is an objective variable to evaluate final flexion after total knee arthroplasty. With a postoperative ROM between 100 degrees and 120 degrees, most activities of daily life can be performed comfortably [27, 28]. The knee ROM usually decreased after TKA surgery comparing with preoperative conditions because of surgery region discomfort, such as incision pain, knee swelling and prosthesis unfamiliar. But most of patients can have knee flexion more than 90 degrees 3 or 4 days postoperative after in hospital rehabilitation according to our experience. One of challenge home rehabilitation has to face with is unsatisfied knee flexion rehabilitation out of hospital due to patients unclear recover aim and poorly exercised. The advantage of KFEH program is to establish a proper target and self-ware rehabilitation test when we ask patients in group KFEH could do flexion practice while sitting a low stool. In our study, ROM showed increasing trend after surgery in both groups. There is obvious difference at the first month, which showed low stool assisted home exercise program group had larger range of knee joint motion (99.4 ± 8.5 degrees and 94.2 ± 9.8 degrees respectively, P < 0.01). The change of ROM between postoperative and preoperative also had similar results (Fig. 2), as well as the absolute values of the KSS pain and function scores and the WOMAC scores, which reflect that patient satisfaction was somewhat better in group KFEH. All of these outcomes results suggest that low stool might improve knee joint range of motion after TKA.
Knee Society Score (KSS) is a clinical rating system published in 1989 to measure the knee in patients having TKA . The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) is developed to evaluate the pain, stiffness and functional limitation condition of patients who suffered osteoarthritis by Bellamy in 1982 . Both of KSS and WOMAC could evaluate knee function and present patients’ satisfaction towards postoperative rehabilitation. In our study, there were no significant differences between group KFEH and group SPT about KSS or WOMAC results, though absolute values of the KSS and the WOMAC scores were better in group KFEH during beginning 3 months after surgery. While several factors contributing to knee function or satisfaction and outcomes vary from patient to patient. Some studies demonstrated that patient perceptions of function could differ from actual function, and patient factors including obesity, motivation, fatigue etc. could also affect results [11, 26, 31]. This may explain ROM difference, an individual factor change, is unlikely to completely influence KSS or WOMAC results.
Physiotherapy cost and inconvenience is a source of concern for patients in group SPT after TKA. Standard supervised physiotherapy treatment usually includes warm heat application, ROM exercises, strength recovery and other applications to avoid postoperative conditions such as loss of motion of the joint, muscle atrophy, tissue edema, functional limitations etc [32, 33]. It is recommended that patients should receive physiotherapy training two or three times weekly to achieving these goals . An American study demonstrated that medicare reimbursements for physical therapy would over 1000 dollar for 12 sessions, and home rehabilitation can much lower the economic burden on patients . In our study, home exercise program involves several actions to rehabilitate ROM of joint, muscle strength, and gait balance. Small low stools would help patients to enhance the flexion of knee joint during exercise. The total cost of each groups mainly contain assessments and training applications. The approximate total costs of 2 months rehabilitation were 1805 RMB in physiotherapy group and 1023 RMB in home exercise group after roughly analysis (Table 4). In consideration of the resident income of China in 2016 was 23821 RMB , home exercise program would lower the economic burden of the patients taking undervalue China medical staffs’ work into account.
Besides function recovery, we also concern whether the procedure of enhancing knee flexion by sitting low stool would cause ligaments injury during rehabilitation. After 12 month follow-up, there was no records reflects patients had ligaments tears or severe pain around the knee joint. DVT, infection or other complications were not occurred as well. Above all, the safety of low stool assisted home exercise program is considered to be noninferior compared with supervised physiotherapy.
This study had some limitations. First, assessor physiotherapist was not blind. Second, the patient compliance of group KFEH is good because of regular follow-up and scoring, but it is not guaranteed that we could get same results from fair or worse compliance patients, such as the ones refused to take part in the study or ones fed up with long-term follow-up. Third, physical therapists differed for each patient, as well as the details of therapy protocol and frequency, and this would result individual difference inevitable. Last, the number of samples is not enough to evaluate some outcomes difference between two groups, and studies with more participants are necessary.