This study has identified 32 concerns that are important to patients during their recovery in the first six weeks following primary TKA. All but two of the identified concerns mapped to four components of the ICF model. Approximately half of the patient concerns identified in this early phase of recovery were not addressed in the content of three commonly used outcome measures.
Two groups of researchers have independently documented concerns of patients prior to undergoing total hip and total knee arthroplasty [8, 9]. In both of these studies, patients were asked to rate their concerns for a 54-item and 29-item questionnaire, respectively. Of the 54 concerns reported by Trousdale et al. , 13 concerns (pain, infection and stiffness in joint after surgery, walking, up and down stairs, in/out of bathtub, driving, dressing, ability to do usual work, return to recreational activities, not knowing what to expect and quality of therapy after surgery) were similar to the concerns identified by subjects in this study. Moran et al.  do not report all 29 items of the questionnaire used in their paper but reported the following top five patient concerns: cancellation of surgery, no decrease in pain, risk of losing the leg, risk of joint infection and risk of dying. While these concerns were generated for TKA and THA patients combined, at the time of this study there was no published evidence to suggest that concerns of patients in the early post-operative phase following total knee and hip arthroplasty are different. However, since that time researchers have shown that the level and time frame of recovery following total hip and knee arthroplasty is different [20, 21], which may lead one to speculate that there may be some differences in concerns between these two patient populations. This may explain why only 13 concerns reported by Trousdale et al.  were similar to concerns in this study. Furthermore, concerns reported by Trousdale et al.  were generated prior to joint replacement surgery as opposed to early after surgery in our study.
Subjects interviewed in post-operative week one were still inpatients at a large tertiary care hospital. Based on the recovery process following primary TKA and the fact that these subjects were interviewed prior to discharge from acute care, it is apparent in Table 1 that patient concerns identified in the first week after surgery were related to this acute stage of their recovery. For example, concerns about competent care, avoiding infection, getting out of bed independently, doing your exercises and ambulation are all pertinent to the early post-operative time frame. Knee range of motion and specifically the amount of flexion is a commonly used outcome measure by health care professionals including surgeons following primary TKA . Furthermore it is common for patients to experience pain following primary TKA . At the time of this study, most patients following primary TKA at the study institution were discharged from hospital on post-operative day four or five. Accordingly, the majority of concerns identified by subjects from post-operative week two onwards (getting in/out of bath, doing housework, cooking, walking, getting in/out of car, comfortably sitting in car, driving, going shopping, returning to hobbies etc.) were activities that a person would normally perform while living in his/her own home.
Turning now to the ICF findings, it is revealing that even in this early phase of recovery following primary TKA, some patient concerns were linked to the ICF Participation component. For example, even within the first six weeks after surgery patients were thinking about 'driving a vehicle', 'going shopping', 'returning to hobbies' and 'going back to regular exercise class/sport'. The concerns about 'returning to sport' and 'driving a vehicle' are especially surprising considering that physical function deteriorates in the first month following TKA  and participants in this study were advised by the health care team not to drive for the first six weeks following surgery.
Concerns that did not map to the ICF were 'receiving appropriate information regarding what to expect with rehabilitation following your surgery' and 'being independent'. These concerns are consistent with previous research, which reported patient concerns about dependence  and the importance of education in the rehabilitation process following total joint replacement surgery .
In this study patient concerns were also mapped to the KOOS, WOMAC and Oxford Knee Scale. As shown in Table 2, 14 of the 32 patient concerns mapped to the KOOS, 11 to the WOMAC and four to the Oxford Knee Scale. With greater than half of all patient concerns missing from these commonly used outcome measures, this study highlights their lack of content validity when used in this early phase of recovery. However, this is not surprising as these outcome measures were not developed by evaluating patient concerns in this early phase of recovery and have traditionally been used by researchers to evaluate outcome a few months or years following TKA. To evaluate outcome in this early phase of recovery researchers and clinicians may need to use a combination of measures to capture the different components of the ICF (i.e. impairments of body structure and function, activity limitations, participation restrictions and environmental factors). Additionally, given the difference in content of currently used measures, such as the KOOS, WOMAC and Oxford Knee Scale and the content identified by patients as important in the early recovery period along with the suggestion from this work that patient concerns for recovery change over time, future research needs to consider outcome measurement in the context of how patient concerns for recovery change over time.
All participants in the study were recruited from a single tertiary care hospital. This may be viewed as decreasing the generalizability of this study to other settings. However, it should be noted that individuals undergoing TKA at this site were not only London residents but also travelled from communities across Southwestern Ontario including rural settings. Also, it is acknowledged that the setting of rehabilitation (home care, inpatient facilities, outpatient clinics) following surgery may influence what is important to patients. In this study, the majority of patients received therapy at home until post-operative week three. After this most patients continued therapy at an outpatient clinic of their choice. Therefore, concerns of patients receiving therapy in settings different from this study may or may not be the same. In addition, the presence or absence of a caregiver in the home may have influenced what patients felt was important to their recovery. Because the living status of patients was not measured, the effect of this variable on patient concerns in this study cannot be determined. Finally, it is possible that this study may not have captured all patient concerns within the first six weeks following primary TKA surgery. Another limitation of this study was that non-English speaking individuals were not included.