Factors that Influence the Range of Motion Following Primary Total Knee Arthroplasty


ABSTRACT:BACKGROUND:Total knee arthroplasty is now practiced increasingly. Arthroplasty is considered successful ifthe knee is stable, painless with good range of motion.OBJECTIVE:To evaluate the importance of different factors that might affect the success rate of total arthroplastyin knee osteoarthritisPATIENTS AND METHODS:Patients with osteoarthritic knees admitted to Basrah center of joint replacement (Basrah TeachingHospital) during the period from January 2017 to October 2018, for total knee replacement wereenrolled in the study. Factors that can affect post-operative range of motion were studied. Theseinvolved factors related to patients (such as age, gender, body mass index, comorbidities, side ofdiseased knee, knee functional score, and range of motion), and those related to the operativeprocedure(duration of operation, use of tourniquet, size of femoral and tibial components, andthe type of polyethylene spacer). The amount of postoperative blood in the drain was also recorded.The follow up period was for up to one year after the surgical operation.RESULTS:Seventy five patients were included in the study, 60 females and 15 males who constituted (80%,20%) respectively. The mean age was (59.20±7.05 years), ranged between (45 - 71 years). The meanBMI of the patients was (26.52 ± 2.67). The tibial size ranged from 3 to 7 with mean(5.08±1.39).The mean pre and post-operative ROM (after one year follow up) was (110.20±20.25)and (116.46±6.76) respectively. The functional knee score (Lysholm score) increased from(50.40±14.67) to (79.48±9.75) post operatively. Fifty two percent of the patients were right sidedknee and 48% of them were left sided. There was no significant statistical correlation between kneeside and range of motion postoperatively. Correlation was also not significant between associateddiseases, gender and post-operative range of motion. Patients with normal BMI had betterpostoperative ROM than over weight and obese patients with mean ROM (120.17±5.49,115.0±10.28 and100.0±16.92) respectively. There was significant negative statistical correlationbetween the age and the post-operative range of motion. There was a significant negative correlationbetween post-operative range of motion, polyethylene spacer, and size of tibial and femoralcomponents used. No correlation was found between the time of operation and postoperative rangeof motion; however, the latter was negatively correlated with the amount of blood in the drain.CONCLUSION:Postoperative range of motion after primary total knee arthroplasty in osteoarthritis of the kneejoint seems to be mostly affected by preoperative range of motion and BMI. Younger patients tendto have a better postoperative range of motion, while larger size of the components of arthroplastyare associated lower post-operative range of motion.