|ORIGINAL CONTRIBUTION - CLINICS IN ORTHOPEDIC SURGERY
|Year : 2016 | Volume
| Issue : 3 | Page : 139-141
Factors affecting knee flexion in primary total knee arthroplasty
Nilay Chhasatia, M Ravikumar, D Dhanalakshmi
Department of Orthopaedics, Southern Railways Headquarters Hospital, Chennai, Tamil Nadu, India
|Date of Web Publication||27-Feb-2017|
Dr. Nilay Chhasatia
Department of Orthopedics, Govt. Medical College, Surat, Gujarat
Source of Support: None, Conflict of Interest: None
Background: The two main measures of a successful primary total knee arthroplasty (TKA) are relief from pain and increase in the range of motion. Because the lifestyle in the Indian subcontinent requires bending of knee beyond 90° during the course of numerous daily chores, the range of knee flexion achieved following surgery is an important clinical outcome measure. This outcome can, however, be influenced by several variables. Objective: This study tried to analyze the possible difference in the postoperative knee flexion among patients undergoing primary TKA and establish the interrelationship among different covariates. Materials and Methods: Thirty-three patients of primary TKA were recruited in the study. Newly operated cases were followed up till 6 months postoperatively. Knee flexion as a part of knee society scoring was carried out as a part of the follow-up. The results obtained were suitably analyzed using the standard statistical tools. Results: Knee flexion in patellar resurfaced post-TKA group (114.17 ± 9.42; P = 0.01) was significantly higher than that in patellar nonresurfaced post-TKA group. Patients who were used to employing some kind of support while negotiating stairs had significantly worse pain scores (41.11 vs. 48.33; P = 0.007] and reduced knee flexion (105.56 vs. 119.17; P = 0.001) compared to those who did not use any support. Compared to males, females were more likely to use support while negotiating stairs (Wald chi square = 4.151, P = 0.04 OR = 8.0). Among all post-TKA patients, males were found to have a greater degree of knee flexion than females (120 vs. 105.37; P = 0.002). No significant difference in knee flexion was observed among age groups and type of arthritis or side of the operated knee. Conclusions: Patellar resurfacing and male sex was associated with a greater degree of post-TKA knee flexion in the study participants.
Keywords: Knee flexion, patellar resurfacing, primary total knee arthroplasty, TKA
|How to cite this article:|
Chhasatia N, Ravikumar M, Dhanalakshmi D. Factors affecting knee flexion in primary total knee arthroplasty. Astrocyte 2016;3:139-41
| Introduction|| |
Total knee arthroplasty (TKA) is being performed successfully for the treatment of osteoarthrosis, rheumatoid arthritis, and numerous other noninfective inflammatory conditions causing chronic crippling knee arthritis. While knee pain is cited as the most common reason for performing primary TKA, greater range of knee flexion is of interest among Indian patients because they often wish to have sufficient knee flexion to sit on flat surfaces or in positions requiring knee flexion beyond 90°.
Biomechanical factors have been found to have a direct association with postoperative knee flexion in various studies. Park et al., in their biomechanical study of three-dimensional (3D) modelled 11 osteoarthritis knees, postulated that overstretched medial and lateral collateral ligament resulted in reduced maximal postoperative knee flexion.
The choice of implant has also been implicated in achieving high maximal knee flexion. Rosen et al., in their study of 47 prospectively followed TKAs, found that cruciate retaining designs had significantly greater postoperative knee flexion compared to cruciate sacrificing surgeries. In their study, sex, body mass index, and preoperative flexion were not significant predictors of knee flexion. Sumino et al. did not find any significant difference in knee flexion in cruciate retaining knees at 1-year follow-up. Ishii et al. studied postoperative knee flexion with regards to posterior femoral condyle offset in both cruciate retaining and posteriorly stabilized implants. They did not find any significant correlation between posterior femoral condylar offset and maximal postoperative knee flexion.
Other factors associated with postoperative knee flexion are preoperative flexion and patellar resurfacing. Keshmiri et al., in their series of 40 consecutive computer-navigated TKAs, found that preoperative sagittal alignment and knee flexion were significant predictors of postoperative patellofemoral kinematics. Langlois et al., in their study of 584 prospective TKAs, reported that, in addition to preoperative knee flexion, patient's height, history of depression, the preoperative flexion angle, a patellar residual subluxation, and the patellar height were statistically significant determinants.
Kim et al. in their study of 373 TKAs reported that, in high-flexion TKA, patellar resurfacing resulted in better mid-term outcomes, and recommended selective patellar resurfacing when performing primary high high-flexion TKA. Sancheti et al. in their study of 248 Indian patients with Indus indigenous TKA implants found preoperative range of movement (ROM) and preoperative functional status as the only significant predictors of ROM and did not find patellar resurfacing as a significant predictor.
| Materials and Methods|| |
Patient population was selected from patients who received a primary TKA in the Department of Orthopaedics, Southern Railways Headquarters Hospital, Chennai, Tamil Nadu. While patients were selected retrospectively from the department registry, all newly operated patients during the period of 1st October 2013 to 30th April 2014 were prospectively followed for at least 6 months. Patients with revision surgeries, fractures, infections, or severe health problems affecting rehabilitation were excluded from the study. A written informed consent was signed by all the patients. Sample size was estimated with the G*power 126.96.36.199 software at 50% power and 5% significance; 33 knees were included in the study. Patients were followed up in the outpatient department for at least 6 months after the primary TKA. Knee society scoring was done by the author for each patient during the follow-up visits. Descriptive and analytical statistics were generated with the help of the Statistical Package for the Social Sciences version 20.0 (released 2011. IBM SPSS Statistics for windows, version 20.0 Armonk, NY; IBM Corp).
| Results|| |
In the present study, the mean knee flexion observed among the participants was 108.03 ± 2.786° [Table 1]. Independent sample t-tests were performed to assess any significant difference in the mean knee flexion among postoperative patients. Statistically significant increase in the mean postoperative knee flexion was found among patients who had patellar resurfacing compared to those whose native patella was preserved: 114.17 ± 9.432 vs. 100.67; P = 0.01 [Table 2].
|Table 2: Mean postoperative knee flexion in patients with patellar resurfacing vs. those in whom the native patella was preserved|
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It was observed that male patients had statistically significant increase in mean postoperative maximal knee flexion compared to females. This increase was approximately 15°. The study also found that females were 8 times more likely (OR = 8; P < 0.05) to use support during climbing staircases as compared to males [Table 3]. Decreased knee flexion (105.56 ± 16 vs. 119.17 ± 4.916; P = 0.001) was observed in patients who were using support while climbing stairs. There was no significant difference in knee flexion among age groups, type of arthritis, and side of knee.
|Table 3: Difference in mean postoperative maximal knee flexion between males and females|
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| Discussion|| |
The study found significant increase in knee flexion among patellar resurfaced patients compared to the nonresurfaced group (114.17 ± 9.432 vs. 100.67; P = 0.01). However, this did not translate to having a better functional score as there was no significant relationship between knee flexion and functional score. There is no consensus over ideal postoperative knee flexion after TKA, and satisfaction of an individual patient depends upon individual functional needs. Majority of Indian patients especially females are concerned about sitting cross legged post TKA. If included in a scoring system, ability to sit cross legged would better reflect the relationship between knee flexion and functional satisfaction of patients.
Male patients in the study had significantly better range of knee flexion compared to females (120 vs. 105.37; P = 0.002). Despite these findings, the study did not find any significant difference in functional and knee scores among males and females, as reported by some authors. Majority of the patients were females, and good-to-excellent mean functional and knee scores among them point towards a more uniform spread of results among sexes.
Climbing staircase is an important individual component of functional score as it reflects the maximum stresses incurred on the patellofemoral joint. It was found that people who used any kind of support while negotiating stairs had significantly worse pain scores (41.11 vs. 48.33; P = 0.007) and knee flexion (105.56 vs. 119.17; P = 0.001) compared to those who did not. The study also found significantly higher odds of female patients using support while climbing stairs (OR = 8.0; P < 0.05). This increase might be unrelated to knee flexion as clinical reduction in mean flexion was mild inclusion of obesity indices in future studies may provide more information regarding outcomes post TKA.
| Conclusion|| |
Because sitting cross legged is a distinctive part of lifestyle among people in the subcontinent, obtaining a greater degree of knee flexion in patients undergoing TKA must remain a major goal. Large detailed studies dwelling upon pre-, intra-, and postoperative factors which govern this post-TKA result must be carried out to establish the favorable factors. This study observed that patellar resurfacing and male gender were associated with significantly greater knee flexion.
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Conflicts of interest
There are no conflicts of interest.
| References|| |
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[Table 1], [Table 2], [Table 3]