Total knee arthroplasty (TKA) is a successful and cost-effective treatment for improving patients' pain and function due to arthritis and it is among the most successful and common major elective surgical operations [1],[2]. After the surgery, most patients improve their pain, self-reported physical functioning, and quality of life. Despite of the improvement in patient selection, surgical technique, and implant design for primary TKA, only 82–89% of the patients were satisfied [3],[4],[5],[6],[7]. The idea of patient satisfaction was first mentioned by Ware et al. in 1873 [8]. Moreover, patients' satisfaction is associated with many factors, such as patients' expectations, pain relief, and improvement in physical function. Due to its sophisticated nature, it is difficult to assess a reliable patient satisfaction because it is liable for biases due to effect of many cofactors [9]. The National Joint Registry (NJR) had considered the Oxford Knee Score (OKS) as a validated patient reported outcome measure (PROM) to assess the outcome of the patients after TKA [2]. The OKS is a reliable and valid patient-centered questionnaire for subjective assessment of pain and function of their knee, and it is easy to administer, simple, and suitable for long period follow-up [2],[10]. It comprises of 12 sections ─ five sections are related to pain and the other seven sections are related to functional capacity [2],[10]. Moreover, each section is rated from 1 to 5 in which score of 1 indicates more severe outcome [2],[10]. Then, the overall scores are added together which range from 12 to 60, with the higher scores corresponding to better outcomes [2],[10],[11]. There are differences between orthopedists and patients assessment of patients' satisfaction, especially in assessing pain and function [2]; orthopedists concern is for the range of motion, alignment, and stability, but patients are focusing more on overall function of the joint [12]. Although pain is the strongest factor that affects satisfaction more than function, it is less amenable to lifestyle and behavioral changes, and it causes a considerable distress [13]. The main objective of this study was to assess the patient satisfaction after primary cemented TKA in Sulaimani city.

The prospective cohort study design was used and 113 patients were included in the study from June 2014 to February 2017. In addition, data were collected from different hospitals in Sulaimani city, and the approval of Research Ethical Committee and informed consent of the patients were obtained.

The inclusion criteria were primary osteoarthritis (OA) combined with disabling knee joint pain that interfered with daily activity and not responding to conservative treatment or arthroscopic management. Moreover, the exclusion criteria were secondary OA, bilateral simultaneous TKA, and contralateral TKA within the follow-up period.

After clinical examination, standard AP (anteroposterior), lateral and axial view X-rays were taken (Figure 1 and Figure 2). In addition, scanogram obtained in patients with short stature, severe deformities, or suspected bowing of femur and tibia (Figure 3).

During the operation, 1.5 g of Cefuroxime was given intravenously with induction as a prophylaxis and most of the patients received spinal anesthesia and the rest received general anesthesia (80 and 33 patients, respectively). In addition, tourniquet was used in all patients and drains were used when the surgeon preferred.

Thereafter, drain removed 24 hours postoperatively and rehabilitation program was started in the first postoperative day. Moreover, the patients discharged when they were able to actively flex their knees beyond 90 degrees and extend the knee and perform active straight leg rising. In addition, patients were examined on weekly basis, stitches were removed after 10–14 days and the patients were examined regularly every two months.

At the end of the six months postoperatively, a checking X-ray of the operated knee was taken and visual analogue scale (VAS), satisfaction rate, OKS, patient expectation, and range of motion (ROM) were recorded. Furthermore, the answers were divided into two groups: the satisfaction group and the expectation group, and each group was divided into two subgroups: satisfied and dissatisfied, and expectation was met or not met, respectively. Moreover, the severity of the pain after surgery was measured by using (0–100 score) of VAS in which 0 indicated no pain and 100 indicated severe pain. Moreover, ROM was obtained by using goniometer and broadly divided into two groups: those with ˃90⁰ flexion of the knee and those with Ë‚90⁰ flexion of the knee.

We used "IBM SPSS Statistics version 21" for the analysis of the data. Moreover, a p-value of (≤0.05) was considered as statistically significant.

Total number of 113 patients was collected; 60 males and 53 females with a male:female ratio of 1:1.1, and a mean ± SD (standard deviation) age of 59 ± 7 years. Moreover, patients' characteristics before surgery have been mentioned in Table 1.

Three patients developed prosthetic infection, two patients sustained periprosthetic fracture and one patient died during the follow-up. All of them were excluded from the study.

For 27 patients, contralateral TKA performed after six months from the initial surgery and they were included in the study.

There was significant improvement in pain severity and OKS (Table 2), and 81 patients (71.7%) were satisfied after TKA surgery (Table 3).

Patient's expectation is an important predicting factor for patient's satisfaction. Bourne et al. [14] showed that the expectation which was not met is considered as predictor of patient's dissatisfaction after TKA. Moreover, surgeon's expectations after TKA are lesser than the patient’s expectations; at the beginning, patients are concerned with pain relief and independent activity, but surgeons know that such expectations may not be fulfilled [15]. Therefore, surgeons should inform the patients about not fulfilled expectations. However, studies showed that good treatment of such expectations can positively influence patient's satisfaction [16],[17].

Patient satisfaction is defined as the degree at which the surgery fulfills the patient and it defines the outcome of surgery. Moreover, we concerned the patient's satisfaction in our study because the knee replacement was basically an elective procedure to restore joint alignment; on the other hand, the surgeon should be aware of the differences in the rate of satisfaction which are multifactorial [18].

Our study showed 71.7% satisfaction after TKA and there was a statistically significant relationship between outcome of TKA surgery measured by OKS and patients' satisfaction (p-value of <0.001) (Table 3). Furthermore, patients' satisfaction in other studies [5],[19],[20],[21] was slightly higher than our result; this may be due to the small sample size in our study, lack of multimodal pain control, and lack of sufficient physiotherapy in affiliated hospitals.

We also found a very close result of patients' expectation to the patients' satisfaction; only 2.5% from the satisfied patients (71.7%) were not meeting their expectations, but all of patients who were dissatisfied (28.3%) diet not meet their expectations with a highly statistically significant relationship (p-value of Ë‚0.001) (Table 3).

Studies [21] showed that 51–56% of the patients who were dissatisfied reported no adverse complaints from their knees in regard to pain and function. Reasonably, this is due to unrealistic expectation toward the outcome of the surgery because most of the patients have high expectations of the outcome after TKA [22],[23]. In our study, despite the VAS score of 36.4 ± 10.7 after the surgery (Table 2), 97.5% from the satisfied patients met their expectation (Table 3), i.e., preoperative expectation defined the patients' satisfaction. Therefore, preoperative expectation should be managed. In addition, the severity of pain measured by VAS was significantly decreased by TKA (p-value of <0.001) (Table 2).

Other variables such as age, gender, body mass index (BMI), and ROM were weak predictors for patients' satisfaction, i.e., statistically insignificant relationships (Table 3). Furthermore, the satisfied patients were slightly younger than patients who dissatisfied because the perception of symptoms is affected by age ─ younger patients may consider disability and pain as more severe than do older patients [24], although older patients were associated with higher dissatisfaction [1],[25],[26]. In our study, same was true for BMI; lesser BMI had better satisfaction (Table 3). Moreover, Spicer et al. [27] showed that BMI of >30 kg/m2 was associated with a higher revision rate and poorer outcomes, while Singh et al. [28] showed that BMI was positively correlated with worse functional impairments. Conversely, several other studies [1],[24],[28] showed significant functional improvement and higher quality of life score in obese patients after TKA as compared to non-obese patients who did not undergo TKA. Concurrently, female gender was slightly less satisfied with the result of their TKA (Table 3).

The effect of ROM for knee joint on the patients' satisfaction was statistically insignificant in our study (Table 3). Conversely, function undoubtedly affects the patients' satisfaction because dissatisfaction depends on abnormal biomechanical function of the joint [29].

The degree of radiographic severity of OA of knee can affect the satisfaction rate after TKA. Our results showed a significant relationship between low radiographic grades which measured by Ahlback grading and dissatisfaction (Table 3). Moreover, this result supports the recommendation suggested by previous studies [30],[31],[32],[33] for performing surgery to patients with severe radiological damage.

At the end of follow-up period, i.e., at the end of six months, mean ± SD of OKS was 41.1 ± 1.9 (maximum OKS was 48) (Table 2) and the more the OKS improved the patients' satisfaction became better (Table 3).

Preoperative pain and function are predictors of postoperative OKS [34]. Our study supported this finding; a lack of improvement in pain in the operated knee is a significant independent predictor of dissatisfaction (Table 3). In addition, the satisfied patients had a significantly better VAS score (Table 3). Moreover, pain at this stage of six months follow-up does not stay permanently and it will change, as the study of Brander et al. [35] showed progressive improvement at five years follow-up duration and almost all of them were satisfied by the same period. Thereof, priorities differ between patients ─ one patient may accept residual pain but the other may tolerate a degree of functional limitation but not pain [2].

Patient expectation can affect the satisfaction rate after surgery and it is the major risk factor for controlling it. Other factors such as residual pain around the knee, function of the replaced knee, and the severity of the arthritis before the surgery are also important contributing factors. Conversely, gender, BMI, and OKS add little influence on the satisfaction rate. Hence, we recommend spending more time with the patients before surgery and discussion of the unrealistic expectation toward the outcome of surgery. In addition, more attention is required for pain control and better quality of physiotherapy in the hospitals, especially in the immediate postoperative period.