Objective: As life expectancy increases, the incidence of degenerative diseases such as osteoarthritis also increases. Dynamic balance is one of the essential factors that affect the mobility and daily living activity of patients suffering from knee osteoarthritis after undergoing Bilateral Total Knee Replacement (BTKR) surgery. Traditional rehabilitation approaches are based on reducing pain and increasing muscle strength, which are applied topically on the knee area. One of the new methods used to improve balance is neurofeedback, which acts at the central nervous system level. This pilot study aims to examine the effect of neurofeedback on dynamic stability and sustained attention in women who underwent BTKA.
Materials & Methods: This is a quasi-experiment study with a pre-test/post-test design and no control group. The study population consisted of all patients with BTKA referred to the outpatient clinic of the Department of Occupational Therapy at Shahid Beheshti University of Medical Sciences from April 2017 to September 2017. Of these patients, 8 female patients with a mean age of 67.5 years (3 months had passed since their surgery) were selected using a convenience sampling method and based on the inclusion and exclusion criteria. 
Results: The inclusion criteria were being over 55 years old; having a history of BTKR surgery in the last 2 to 4 months; being able to walk independently; using a cement prosthesis; lacking a record of cognitive problems (mini-mental state exam score> 20), cardiovascular diseases, uncontrolled high blood pressure, visual impairment, drug abuse or alcohol use, vestibular disorders that can impair balance, use of neuroleptics and sedatives; not receiving neurofeedback before this study, or undergoing surgery in other joints of lower limbs, such as ankle or hip. The exclusion criteria were the absence of more than two sessions from therapeutic protocol and unwillingness to collaborate in the research process. All patients received 8 sessions of standard neurofeedback training. Assessments were done at three times: before the intervention, and at the 4th and 8th sessions using vigilance subscale of Vienna test system and Biodex balance system (dynamic stability level 6 test). Data analysis was done in SPSS V. 22 using repeated-measures ANOVA and paired-samples t test. P<0.05 was considered as the significance level. There was a significant improvement in the mean score of dynamic stability after neurofeedback training (P<0.05), but the mean scores of sustained attention did not change significantly (P>0.05). However, the mean reaction time decreased significantly (P<0.05). Moreover, a gradual increase in the beta wave was observed during treatment, but it was not statistically significant.
Conclusion: Neurofeedback training can improve dynamic stability in female patients with knee osteoarthritis 4 months after BTKR surgery, but it has limited effects on their sustained attention. Therefore, this non-invasive and uncomplicated program can be used as a complementary treatment method for the rehabilitation of these patients.

Objective: This study aims to translate and cross-culturally adapt the University of California at Los Angles Activity Scale (UCLA) to Iranian samples and evaluate the reliability and validity of the Persian UCLA in candidates for knee replacement surgery. 
Materials & Methods: In this cross-sectional study, cross-cultural adaptation was performed according to the international quality of life assessment protocol in three stages: standard forward translation, translation synthesis, and backward translation. The Persian UCLA, tegner activity scale (TAS), short-form health survey (SF-36) and international physical activity questionnaire (IPAQ) were completed by 103 participants (candidates for knee replacement surgery). The Persian UCLA questionnaire was re-completed by 66 participants in the retest session with an interval of 3-7 days. An intra-class correlation coefficient (ICC) was used to evaluate test-retest reliability. The standard error of measurement (SEM) was used to determine smallest detectable change (SDC) in scores. To evaluate convergent validity of the Persian UCLA, its correlation with TAS, SF-36, and IPAQ was assessed using Spearman’s correlation test. The ceiling and floor effects were also calculated.
Results: In the Persian version, no special changes were made and no problem or ambiguity was reported by the respondents based on a pilot study. The type of activities mentioned in the original version was not changed either and none of the participants had difficulty understanding the items. The Mean±SD of UCLA scores were 2.98±1.37 in the test phase and 2.89±1.32 in the retest phase. Psychometric tests results showed acceptable test-retest reliability of the Persian UCLA (ICC=0.96, 95% CI=0.93-0.97). Given an SDC score of 0.50 at 95% confidence interval, it can be said that if the UCLA score be above or less than 0.50, there is an improvement or decline in the activity level of patients. Based on the results of Spearman correlation test, the Persian UCLA showed a strong correlation with TAS (rs=0.71, P<0.001), a moderate correlation with IPAQ (rs=0.58, P<0.001) and physical health summary component of SF-36 (rs=0.59, P<0.001), and a weak correlation with the mental health summary component of SF-36 (rs=0.39, P<0.001). The Persian UCLA questionnaire had no ceiling or floor effects.
Conclusion: The Persian version of the UCLA questionnaire has acceptable reliability and validity for Iranian candidates for knee replacement surgery. 
 

Introduction The psoas muscle plays an essential role in the hip and lumbar spine. Total hip arthroplasty surgery can change the ipsilateral psoas muscle, which may affect lumbar biomechanics and accelerate disk degeneration. We present a clinical study that suggests a potential association between unilateral psoas muscle atrophy after hip replacement surgery and subsequent low back pain
Case description A 53-year-old man with a history of right total hip arthroplasty for osteoarthritis presented with left lumbosciatalgia 6 years after surgery. In the physical examination, the patient exhibited weakness 2/5 in Kendall’s muscle grading system in the right hip flexion and left extensor hallucis longus and triceps surae. Magnetic resonance imaging revealed a degenerative disk L5-S1 and severe unilateral atrophy of the right psoas muscle. Conservative treatment through physiotherapy was initiated, but persistent pain ultimately necessitated microdiscectomy at the L5–S1 level.
Conclusion Total hip arthroplasty surgery may lead to long-term unilateral atrophy of the ipsilateral psoas muscle and alter lumbar biomechanics, potentially accelerating the disk degeneration and subsequent low back pain. Investigating this possible correlation may offer greater clarity regarding low back pain after total hip arthroplasty. In our case, conservative treatment through 15 sessions of physical therapy resulted in very limited improvement, and advanced diskopathy required surgical intervention to decompress the affected lumbar root.