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Factors Influencing Range of Motion After Contemporary Total Knee Arthroplasty
The Journal of Arthroplasty Vol. 20 No. 7 2005
Factors Influencing Range of Motion After Contemporary Total Knee Arthroplasty Akihiro Kotani, MD, Akihiko Yonekura, MD, and Robert B. Bourne, MD, FRCS(C)
Abstract: A detailed analysis of 219 total knee arthroplasties performed with a single implant design was performed. Factors significantly affecting the postoperative range of motion of total knee arthroplasties 2 years after surgery included preoperative diagnosis and preoperative range of motion. Sex, age, body mass index, femoral component size, posterior cruciate ligament status, or fixed vs mobile bearing design did not correlate with knee range of motion 2 years postoperatively. Key words: total knee arthroplasty, range of motion. n 2005 Elsevier Inc. All rights reserved.
The range of motion achieved after a total knee arthroplasty (TKA) is an important clinical outcome affecting many activities of daily living [1- 5]. A number of reports have described the factors affecting range of motion after TKA. Among the important factors are preoperative knee range of motion [1,4 - 7], tibiofemoral varus/valgus angle [7], type of disease [4,7], patient’s age [8], preoperative knee joint function score [1], surgical technique used; design of the implant, and postoperative therapy. Many of these studies might be considered historical, as there have been many innovations in TKA instrumentation, surgical technique, and implant design. The objective of this study was to identify and to investigate the factors that affect the range of motion after use of a contemporary knee arthroplasty.
Methods One hundred ninety patients in whom 219 contemporary TKAs of a single design were prospectively evaluated preoperatively and postoperatively at 3 months, 1 year, and 2 years after surgery to determine factors that might affect postoperative range of motion. The influence of implant positioning and postoperative range of motion was assessed using standing anteroposterior, lateral, and axial patellofemoral radiographs. Specifically, femoral (a and c angles), tibial (b and d angles), and patellar (component tilt angle and patellar component deviation ratio) component positioning were determined (Fig. 1A -C) and correlated with postoperative range of motion. Statistical analysis was performed to identify the factors that affect postoperative range of motion of the knee joint. Analyzed parameters were sex, age, body mass index (BMI), preoperative diagnosis, preoperative range of motion of the knee joint, tibiofemoral varus/valgus angle before operation, lateral inclination angle of the patellar implant, lateral displacement of patellar implant femoral and tibial component positioning, and size of the femoral component used. Mann-Whitney U test and Kruskal-Wallis test were used for statistical testing of the difference in mean values between unpaired 2 or 3 groups, respectively, and a significant
From the Adult Reconstructive Surgery, London Health Science Centre, University of Western Ontario, London, Ontario, Canada. Submitted January 26, 2004; accepted December 13, 2004; Benefits or funds were received in partial or total support of the research material described in this article. These benefits or support were received from the following sources: Smith and Nephew. Reprint requests: Robert B. Bourne, MD, FRCS(C), London Health Sciences Centre, 339 Windermere Road, London, Ontario, Canada N6A 5A5. n 2005 Elsevier Inc. All rights reserved. 0883-5403/05/1906-0004$30.00/0 doi:10.1016/j.arth.2004.12.051
850
Range of Motion After Contemporary Total Knee Arthroplasty ! Kotani et al
851
Fig. 1. A, Illustrates how the lateral inclination angle of the patella (a) and lateral displacement of the patella were measured. B, Outlines how femoral component (a) and tibial component (b) positioning were determined on anteroposterior radiograph. C, Demonstrates how femoral component (d) and tibial component (a) positioning were determined on lateral radiograph.
difference was found with a risk less than 5%. Statistical testing of the difference in mean values between paired 2 groups was performed by Wilcoxon signed rank test with a risk less than 5%. For analysis of the correlation of the 2 variants, Pearson correlation coefficient was calculated. With a risk of less than 5%, they were judged as weakly correlated when the absolute value of the coefficient of correlation was 0.2 or greater, moderately correlated when it was 0.4 or greater, and strongly correlated when it was 0.7 or greater.
Results One hundred ninety consecutive patients in whom 219 Genesis II TKAs (Smith & Nephew, Memphis, Tenn) were followed prospectively to assess postoperative range of motion. Minimum follow-up was 2 years. The operations were performed by or under the supervision of the senior author (RBB). The patients were between 41 and 89 years of age at the time of the operation, averaging 68.4 F 9.6 years. Seventy-six were men and 113 were women. The operation was performed on 113 right knees and 106 left knees, including the cases in which surgery was performed on both sides. Preoperative diagnosis was osteoarthritis (OA) in 203 subjects (92.7%), rheumatoid arthritis (RA) in 10 subjects (4.6%), and avascular necrosis of the medial condyle of the femur in 1 subject (0.5%). In
addition, there were 2 cases of patellofemoral arthrosis (0.9%) and 1 case each of secondary arthritis developed after hemophiliac arthrosis, remote septic arthritis, and fibrous dysplasia. Eighty-one knees (37.0%) had undergone at least one other knee operation before TKA, and 135 knees (61.6%) had had no previous surgery. The 81 knees that had undergone a previous operative procedure included 62 arthroscopic operations (including synovectomy and meniscectomy), 16 high tibial valgus osteotomies, 2 varus osteotomies of the distal femur, 2 Hauser’s procedures, 1 Elmslie-Trillat’s procedure, 7 open reduction and internal fixation procedures for fractures, 1 repair of a ruptured tendon of the quadriceps muscle of the thigh, and 1 repair of a ruptured tibial medial collateral ligament (overlapping cases included). In all cases, the Genesis II Total Knee System (Smith & Nephew) was used (posterior cruciate ligament retaining [CR] type in 66 knees [30.1%], posterior cruciate ligament sacrificing [PS] type in 129 knees [58.9%], and posterior cruciate ligament retaining mobile bearing [MB] type in 24 knees [11.0%]). Posterior cruciate ligament (PCL)– sacrificing implants were used in patients with deformities greater than 158, a prior high tibial valgus osteotomy, a prior patellectomy, or in patients with RA. Posterior cruciate retaining implants were used in the remaining patients with deformities less than 158. Patients treated with mobile bearing implants were similar to the PCL
852 The Journal of Arthroplasty Vol. 20 No. 7 October 2005
Relationship Between the Postoperative Range of Motion of the Knee Joint and Preoperative Factors Such as Sex, Age, BMI, Preoperative Diagnosis, Preoperative Range of Motion of the Knee Joint, Preoperative Tibiofemoral Varus/Valgus Angle, and Preoperative Patellar Tracking Preoperatively, no significant sex difference was noted in knee range of motion (115.58 F 11.78 of flexion and 5.58 F 5.28 of extension in male patients and 111.58 F 15.18 of flexion and 4.98 F 4.88 of extension in female patients). The average flexion angle of the knee at 3 months after surgery was 114.48 F 12.78 in males and 110.08 F 13.48 in females, the flexion angle significantly greater in males. There were no sex differences in the flexion angle or extension angles of the knees at 1 year (118.78 F 10.98 of flexion and 1.68 F 2.88 of extension in male patients and 116.28 F 14.28 of flexion and 1.38 F 2.78 of extension in female patients) or 2 years (116.48 F 11.38 of flexion and 0.48 F 1.18 of extension in male patients and 118.38 F 13.68 of flexion and 1.28 F 2.68 of extension in female patients) after surgery. There was no correlation between age and postoperative range of motion of the knee (r = 0.08 and P = .54 at 3 months, r = 0.10 and P = .42 at 1 year, and r = 0.06 and P = .65 at 2 years after surgery). Body mass index had a weak negative correlation with the flexion angle at 1 year after surgery (r = 0.31, P = .01). However, there was no correlation between BMI and flexion angle at 3 months (r = 0.09, P = .48) and 2 years (r = 0.17, P = .18) after surgery. There was no correlation between BMI and extension angle at any time after surgery. When the patient’s preoperative diagnosis, namely OA and RA, were compared, there was no difference in the flexion angle of the knee before
surgery. Postoperatively, the flexion arcs were 114.48 in OA and 124.48 in RA at 3 months after surgery, 117.18 in OA and 130.08 in RA at 1 year, and 116.68 in OA and 132.58 in RA at 2 years after surgery, respectively. At each follow-up, the flexion angles were significantly greater in the RA group postoperatively ( P = .007 at 3 months, P = .008 at 1 year, P = .024 at 2 years after surgery). There were no differences in the extension angles of the knees between OA and RA postoperative patients. The preoperative flexion angles had a weak positive correlation with the flexion angles at 3 months (r = 0.27, P = .022) and 1 year (r = 0.32, P = .007) after surgery, but at 2 years after surgery, there was no correlation. The preoperative tibiofemoral varus/valgus angle was classified as neutral in 15 knees (10%), varus in 118 knees (78.7%), and valgus in 17 knees (11.3%). Although there was no statistical correlation between preoperative tibiofemoral varus/valgus angle and postoperative range of motion of the knee(r = 0.02 and P = .91 at 3 months, r = 0.01 and P = .92 at 1 year, and r = 0.03 and P = .86 at 2 years after surgery), PCL-sacrificing implants were more often selected for knees with greater deformities (ie, N158) than knees than the other 2 implant designs (ie, CR and MB) (Fig. 2). There was no correlation between the lateral inclination angle of patella and the postoperative range of motion of the knee (r = 0.16 and P = .29 at 3 months, r = 0.18 and P = .24 at 1 year, and r = 0.08 and P = .60 at 2 years after surgery). There was also no correlation between the lateral displacement of patella and the postoperative range of motion of the knee (r = 0.01 and P = .97 at 3 months, r = 0.01 and P = .97 at 1 year, and r = 0.05 and P = .75 at 2 years after surgery). Postoperative Flexion Angle [degree]
retaining group but were part of a multicenter randomized trial. The operation was performed through a medial parapatellar approach in all cases. All components were cemented. The patella was resurfaced in 211 knees (96.3%) and not resurfaced in 8 knees (3.7%). A lateral retinacular release was performed in 7 knees (3.2%). In postoperative physical therapy, walking with partial to full weight bearing began the day after surgery. Patients were discharged 5 days after surgery. Outpatient physiotherapy was prescribed in all patients. A continuous passive motion machine was not used after surgery.
150 140 130 120 110 100 90 80 70 60 -30 -20 -10 0 10 20 30 Preoperative Tibiofemoral Varus/Valgus Angle [degree] CR MB PS
Fig. 2. Relationship between preoperative tibiofemoral varus/valgus angles and postoperative flexion angles.
Range of Motion After Contemporary Total Knee Arthroplasty ! Kotani et al
853
Relationship Between the Component Alignment Angles and the Postoperative Range of Motion of the Knee Joint Mean values for a and b angles were 95.48 F 2.38 and 89.18 F 1.68, respectively. The postoperative tibiofemoral varus/valgus angle calculated from these angles (3608 a b) was between 1678 and 1828, averaging 175.58 F 2.88. The mean c and d angles were 0.88 F 3.18 and 85.88 F 2.58, respectively. The postoperative lateral alignment of the knee calculated from these angles (c + 908 d) was between 68 and 178, averaging 4.98 F 4.28. Concerning the patellar component, the patella component tilt angle was 7.88 F 5.58 on average, and the patella component deviation ratio was 49.4% F 4.3% on average (Table 1). There was no correlation between the positioning of the femoral and tibial components, postoperative tibiofemoral varus/valgus alignment angles, or postoperative lateral alignment of the knee and the postoperative range of motion of the knee. Relationship Between the Size of the Femoral Component and Postoperative Range of Motion of the Knee Joint The size of the femoral components tended to be greater in males and smaller in females (Fig. 3). The postoperative range of motion was compared by femoral component sizes stratified into a small-sized group (sizes 3 and 4, group S), a medium-sized group (sizes 5 and 6, group M), and a large-sized group (sizes 7 and 8, group L). There were no significant differences in the preoperative range of motion of the knees among these 3 groups. At 3 months and 1 year after surgery, the flexion arcs of the knees in group L were significantly greater by 58 (at 3 months) to 78 (at 1 year)
Fig. 3. Femoral component size distribution.
compared to the other 2 groups (Fig. 4). There were no significant differences in the flexion arcs among these 3 groups 2 years after surgery. There were no significant differences in the extension angles of the knees among the groups at any time after surgery. Relationship Between Device Models and Postoperative Range of Motion of the Knee Joint There was no significant difference in the preoperative flexion or extension ranges of motion among the 3 component designs of CR, PS, and MB (Fig. 5). At 3 months and at 1 year after surgery, [degree] 135
*
130
*
Mean 95.4 89.1 4.5
2.3 1.6 2.8
Min 90.0 83.5 2.0
Max 105.0 94.0 13.0
120 115 S M L
110 105 100
* P < .05
95
0.8 85.8 4.9
3.1 2.5 4.2
10.0 79.0 6.0
11.5 94.0 17.0
7.8
5.5
11.0
56.0
49.4
4.3
37.3
63.2
Extension
a Angle (degree) b Angle (degree) Postoperative tibiofemoral varus/ valgus angle (degree) c Angle (degree) d Angle (degree) Postoperative lateral alignment of the knee (degree) Patellar component tilt (degree) Patellar component deviation (%)
SD
Flexion
125
Table 1. Component Alignment Angles
15 10 5 0 -5
Pre-Ope
3M
1Y
2Y
Fig. 4. Relationship between femoral component size and range of motion.
854 The Journal of Arthroplasty Vol. 20 No. 7 October 2005
Flexion
[degree] 135 130 125 120 115 110 105 100 95
*
*
CR MB PS
Extension
90
* p<0.05
15 10 5 0 -5
Pre-Ope
3M
1Y
2Y
Fig. 5. Relationship between TKA design and range of motion.
the flexion angles in the PS group were significantly greater by 48 (at 3 months) to 68 (at 1 year) compared to the other 2 groups. There were no significant differences in the flexion ranges of motion among these 3 groups 2 years after surgery. There were no significant differences in the extension ranges of motion among the 3 groups at any time after surgery.
Discussion Postoperative range of motion is an important determinant of patient satisfaction after TKA. In daily life, activities such as a deep knee bend require knee flexion of 1108 or more. If a flexion arc of 1108 or more is achieved, improvement in the performance of daily activities can be expected. A number of previous reports have described factors that affect the range of motion after total knee joint arthroplasty [4,5,9 -12]. These include proper ligament balancing, management of the PCL, and flexion of the knee at the time of the wound closure [2,9,13]. Postoperative physiotherapy has also been demonstrated to be an important factor in achieving knee range of motion [13]. The purpose of this single center, single surgeon study was to evaluate these factors using a single contemporary knee arthroplasty design. Our study agrees with the report of Schurman et al [7], that sex did not appear to be an important factor affecting knee joint range of motion. The influence of age on postoperative knee range of motion remains controversial. Horikawa et al
[14] found that preoperative range of motion was not correlated with age, but that there was a weak correlation between postoperative range of motion and age (r = 0.277, P b .05). Schurman et al [8] divided 25 patients with preoperative range of motion of less than 788 into 2 groups: one group of patients 62 years or younger and a second group older than 63 years. The younger group showed a mean postoperative range of motion of 838, whereas the older group had a mean value of 1008, demonstrating that the age was a factor. In contrast, Harvey et al [9] and Anouchi et al [1] reported no correlation between age and postoperative knee range of motion. In our study, we also found no age-related effect on postoperative knee range of motion. There are some reports indicating that obesity has an adverse effect on postoperative knee range of motion due to soft tissue impingement between the femur and the tibia, which restricts flexion of the knee [11,15]. Shoji et al [11] concluded that obese patients accounted for a larger percentage of the patients with a poor range of motion. Lizaur et al [15] reported that BMI was significantly correlated (r = 0.25, P = .023) with postoperative range of motion. In our study, BMI was not strongly correlated with postoperative range of motion. Regarding preoperative diagnosis, a number of comparative studies of OA and RA have been conducted [7- 9,12,16,17]. Most, but not all of these studies, have reported a greater improvement rate in range of motion in the RA group who had a poorer preoperative range of motion. In our study, there was no difference in preoperative range of motion between the OA and RA groups. Postoperatively, the RA group showed a significantly greater range of motion in agreement with most published studies. From the standpoint of preoperative range of motion, most reports have demonstrated that a greater postoperative flexion arc was achieved in patients with greater preoperative range of motion of the knee joint. Kurosaka et al [13] reported that preoperative range of motion of the knee joint was the most important factor. This investigation did find that patients with poor preoperative flexion showed greater improvement than those with good preoperative flexion. Our study results demonstrated some positive correlation between preoperative flexion and postoperative flexion at 3 months and 1 year, but no evident correlation at 2 years after surgery. Mean preoperative range of motion of the subjects included in our study was 1158, which was considerably greater than that previously
Range of Motion After Contemporary Total Knee Arthroplasty ! Kotani et al
reported, and this may be a reason for the absence of a significant correlation. In our study, preoperative tibiofemoral deformity was not found to be a significant factor affecting postoperative range of motion as was found by Kawamura and Bourne [18] and Shurman et al [8]. This may be due to the fact that PCLsubstituting implants were selected for patients with greater deformity. To demonstrate the relation between preoperative patellar tracking and postoperative flexion, the correlation between the preoperative lateral tilt and lateral displacement of the patella was investigated [19,20]. As far as we know, there is no study report available in the literature regarding the relationship between patellar tracking and postoperative flexion. Our study results showed no correlation between them. We performed the arthroplasty of patellar component in 211 of 219 patients, and excellent patellar tracking was achieved with a mean patellar component tilt of 7.88 F 5.58 and a mean patella component deviation of 49.4% F 4.3%. This may be considered the reason for the absence of a correlation. Controversy exists with regards the effect of femoral and tibial implant positioning on eventual TKA range of motion. Horikawa et al [14], Walker and Garg [21], and Schurman et al [7] are not in agreement. The use of modern instrumentation that accurately positions the femoral, tibial, and patellar components may have rendered implant positioning a nonissue in this study. Our study was not consistent with the finding of Kurosaka et al [13] that range of motion was affected by femoral component size. Our results suggest that the femoral component size did not influence final knee range of motion after TKA. A number of previous studies have reported on the comparison of postoperative range of motion between PCL-preserving and PCL-sacrificing total knee arthroplasties. Andriacchi et al [22] reported that preservation of PCL induced rollback of femur and consequently increased postoperative flexion. On the other hand, Dennis et al [2] reported that it was possible to maintain more normal kinematics of knee by using the post/cam mechanism of PCL-sacrificing implants. Becker et al [23] investigated 30 patients with a PCL-preserving design in one knee and a PCL-sacrificing design in the other knee. His group reported that the PCLsacrificing design had poor preoperative range of motion but achieved better postoperative flexion compared with the PCL-preserving implants. In our study, the range of motion of PCL-sacrificing TKAs was significantly greater than with PCL-
855
preserving and mobile bearing TKAs up to 1 year postoperatively, but no differences were noted at 2 years after surgery.
References 1. Anouchi YS, McShane M, Kelly Jr F, et al. Range of motion in total knee replacement. Clin Orthop 1996;331:87. 2. Dennis DA, Komistek RD, Stiehl JB, et al. Range of motion after total knee arthroplasty: the effect of implant design and weight bearing conditions. J Arthroplasty 1998;13:748. 3. Dennis DA, et al. In vivo knee kinematics derived using an inverse perspective technique. Clin Orthop 1996;331:107. 4. Maloney WJ, Schurman DJ. The effects of implant design on range of motion after total knee arthroplasty. Total condylar versus posterior stabilized total condylar designs. Clin Orthop 1992; 278:147. 5. Parsley BS, Engh GA, Dwyer KA. Preoperative flexion. Does it influence postoperative flexion after posterior - cruciate – retaining total knee arthroplasty? Clin Orthop 1992;275:204. 6. Menke W, Schmitz B, Salm S. Range of motion after total knee arthroplasty. Arch Orthop Trauma Surg 1992;III:280. 7. Schurman DJ, Parker JN, Ornstein D. Total condylar knee replacement. J Bone Joint Surg 1985; 67A:1006. 8. Schurman DJ, Matityahu A, Good SB, et al. Prediction of postoperative knee flexion in InsallBurstein II total knee arthroplasty. Clin Orthop 1998;353:175. 9. Harvey IA, Barry K, Kirby SPJ, et al. Factors affecting the range of movement of total knee arthroplasty. J Bone Joint Surg Br 1993;75:950. 10. Ritter MA, Campbell ED. Effect of range of motion on the success of a total knee arthroplasty. J Arthroplasty 1987;2:95. 11. Shoji H, Solomonow M, Yoshino S, et al. Factors affecting postoperative flexion in total knee arthroplasty. Orthopedics 1990;13:643. 12. Tew M, Forster IW, Wallace WA. Effect of total knee arthroplasty on maximal flexion. Clin Orthop 1989; 247:168. 13. Kurosaka M, Yoshiya S, Mizuno K, et al. Maximizing flexion after total knee arthroplasty. J Arthroplasty 2002;17:59. 14. Horikawa K, Wakabayashi H, Uchida A, et al. Factors influencing the postoperative range of motion after total knee arthroplasty. J Chubu Seisai 1999:717. 15. Lizaur A, Marco L, Cebrian R. Preoperative factors influencing the range of movement after total knee arthroplasty for severe osteoarthritis. J Bone Joint Surg Br 1997;79:629.
856 The Journal of Arthroplasty Vol. 20 No. 7 October 2005 16. Ritter MA, Stringer EA. Predictive range of motion after total knee replacement. Clin Orthop 1979; 143:115. 17. Tew M, Forster IWF. Effect of knee replacement on flexion deformity. J Bone Joint Surg 1987;69B:395. 18. Kawamura H, Bourne RB. Factors affecting range of flexion after total knee arthroplasty. J Orthop Sci 2001;6:248. 19. Chew JTH, Stewart NJ, Hanssen AD, et al. Differences in patellar tracking and knee kinematics among three different total knee designs. Clin Orthop 1997;345:87.
20. Gomes LSM, Bechtold JE, Gustilo RB. Patellar prosthesis position in total knee arthroplasty. Clin Orthop 1988;236:72. 21. Walker PS, Garg A. Range of motion in total knee arthroplasty. A computer analysis. Clin Orthop 1991;262:227. 22. Andriacchi TP, et al. Retention of the posterior cruciate in total knee arthroplasty. J Arthroplasty 1998:13. 23. Becker MW, Insall JN, Faris PM. Bilateral total knee arthroplasty. One cruciate retaining and one cruciate substituting. Clin Orthop 1991;271:122.
Factors Influencing Range of Motion After Contemporary Total Knee Arthroplasty Akihiro Kotani, MD, Akihiko Yonekura, MD, and Robert B. Bourne, MD, FRCS(C)
Abstract: A detailed analysis of 219 total knee arthroplasties performed with a single implant design was performed. Factors significantly affecting the postoperative range of motion of total knee arthroplasties 2 years after surgery included preoperative diagnosis and preoperative range of motion. Sex, age, body mass index, femoral component size, posterior cruciate ligament status, or fixed vs mobile bearing design did not correlate with knee range of motion 2 years postoperatively. Key words: total knee arthroplasty, range of motion. n 2005 Elsevier Inc. All rights reserved.
The range of motion achieved after a total knee arthroplasty (TKA) is an important clinical outcome affecting many activities of daily living [1- 5]. A number of reports have described the factors affecting range of motion after TKA. Among the important factors are preoperative knee range of motion [1,4 - 7], tibiofemoral varus/valgus angle [7], type of disease [4,7], patient’s age [8], preoperative knee joint function score [1], surgical technique used; design of the implant, and postoperative therapy. Many of these studies might be considered historical, as there have been many innovations in TKA instrumentation, surgical technique, and implant design. The objective of this study was to identify and to investigate the factors that affect the range of motion after use of a contemporary knee arthroplasty.
Methods One hundred ninety patients in whom 219 contemporary TKAs of a single design were prospectively evaluated preoperatively and postoperatively at 3 months, 1 year, and 2 years after surgery to determine factors that might affect postoperative range of motion. The influence of implant positioning and postoperative range of motion was assessed using standing anteroposterior, lateral, and axial patellofemoral radiographs. Specifically, femoral (a and c angles), tibial (b and d angles), and patellar (component tilt angle and patellar component deviation ratio) component positioning were determined (Fig. 1A -C) and correlated with postoperative range of motion. Statistical analysis was performed to identify the factors that affect postoperative range of motion of the knee joint. Analyzed parameters were sex, age, body mass index (BMI), preoperative diagnosis, preoperative range of motion of the knee joint, tibiofemoral varus/valgus angle before operation, lateral inclination angle of the patellar implant, lateral displacement of patellar implant femoral and tibial component positioning, and size of the femoral component used. Mann-Whitney U test and Kruskal-Wallis test were used for statistical testing of the difference in mean values between unpaired 2 or 3 groups, respectively, and a significant
From the Adult Reconstructive Surgery, London Health Science Centre, University of Western Ontario, London, Ontario, Canada. Submitted January 26, 2004; accepted December 13, 2004; Benefits or funds were received in partial or total support of the research material described in this article. These benefits or support were received from the following sources: Smith and Nephew. Reprint requests: Robert B. Bourne, MD, FRCS(C), London Health Sciences Centre, 339 Windermere Road, London, Ontario, Canada N6A 5A5. n 2005 Elsevier Inc. All rights reserved. 0883-5403/05/1906-0004$30.00/0 doi:10.1016/j.arth.2004.12.051
850
Range of Motion After Contemporary Total Knee Arthroplasty ! Kotani et al
851
Fig. 1. A, Illustrates how the lateral inclination angle of the patella (a) and lateral displacement of the patella were measured. B, Outlines how femoral component (a) and tibial component (b) positioning were determined on anteroposterior radiograph. C, Demonstrates how femoral component (d) and tibial component (a) positioning were determined on lateral radiograph.
difference was found with a risk less than 5%. Statistical testing of the difference in mean values between paired 2 groups was performed by Wilcoxon signed rank test with a risk less than 5%. For analysis of the correlation of the 2 variants, Pearson correlation coefficient was calculated. With a risk of less than 5%, they were judged as weakly correlated when the absolute value of the coefficient of correlation was 0.2 or greater, moderately correlated when it was 0.4 or greater, and strongly correlated when it was 0.7 or greater.
Results One hundred ninety consecutive patients in whom 219 Genesis II TKAs (Smith & Nephew, Memphis, Tenn) were followed prospectively to assess postoperative range of motion. Minimum follow-up was 2 years. The operations were performed by or under the supervision of the senior author (RBB). The patients were between 41 and 89 years of age at the time of the operation, averaging 68.4 F 9.6 years. Seventy-six were men and 113 were women. The operation was performed on 113 right knees and 106 left knees, including the cases in which surgery was performed on both sides. Preoperative diagnosis was osteoarthritis (OA) in 203 subjects (92.7%), rheumatoid arthritis (RA) in 10 subjects (4.6%), and avascular necrosis of the medial condyle of the femur in 1 subject (0.5%). In
addition, there were 2 cases of patellofemoral arthrosis (0.9%) and 1 case each of secondary arthritis developed after hemophiliac arthrosis, remote septic arthritis, and fibrous dysplasia. Eighty-one knees (37.0%) had undergone at least one other knee operation before TKA, and 135 knees (61.6%) had had no previous surgery. The 81 knees that had undergone a previous operative procedure included 62 arthroscopic operations (including synovectomy and meniscectomy), 16 high tibial valgus osteotomies, 2 varus osteotomies of the distal femur, 2 Hauser’s procedures, 1 Elmslie-Trillat’s procedure, 7 open reduction and internal fixation procedures for fractures, 1 repair of a ruptured tendon of the quadriceps muscle of the thigh, and 1 repair of a ruptured tibial medial collateral ligament (overlapping cases included). In all cases, the Genesis II Total Knee System (Smith & Nephew) was used (posterior cruciate ligament retaining [CR] type in 66 knees [30.1%], posterior cruciate ligament sacrificing [PS] type in 129 knees [58.9%], and posterior cruciate ligament retaining mobile bearing [MB] type in 24 knees [11.0%]). Posterior cruciate ligament (PCL)– sacrificing implants were used in patients with deformities greater than 158, a prior high tibial valgus osteotomy, a prior patellectomy, or in patients with RA. Posterior cruciate retaining implants were used in the remaining patients with deformities less than 158. Patients treated with mobile bearing implants were similar to the PCL
852 The Journal of Arthroplasty Vol. 20 No. 7 October 2005
Relationship Between the Postoperative Range of Motion of the Knee Joint and Preoperative Factors Such as Sex, Age, BMI, Preoperative Diagnosis, Preoperative Range of Motion of the Knee Joint, Preoperative Tibiofemoral Varus/Valgus Angle, and Preoperative Patellar Tracking Preoperatively, no significant sex difference was noted in knee range of motion (115.58 F 11.78 of flexion and 5.58 F 5.28 of extension in male patients and 111.58 F 15.18 of flexion and 4.98 F 4.88 of extension in female patients). The average flexion angle of the knee at 3 months after surgery was 114.48 F 12.78 in males and 110.08 F 13.48 in females, the flexion angle significantly greater in males. There were no sex differences in the flexion angle or extension angles of the knees at 1 year (118.78 F 10.98 of flexion and 1.68 F 2.88 of extension in male patients and 116.28 F 14.28 of flexion and 1.38 F 2.78 of extension in female patients) or 2 years (116.48 F 11.38 of flexion and 0.48 F 1.18 of extension in male patients and 118.38 F 13.68 of flexion and 1.28 F 2.68 of extension in female patients) after surgery. There was no correlation between age and postoperative range of motion of the knee (r = 0.08 and P = .54 at 3 months, r = 0.10 and P = .42 at 1 year, and r = 0.06 and P = .65 at 2 years after surgery). Body mass index had a weak negative correlation with the flexion angle at 1 year after surgery (r = 0.31, P = .01). However, there was no correlation between BMI and flexion angle at 3 months (r = 0.09, P = .48) and 2 years (r = 0.17, P = .18) after surgery. There was no correlation between BMI and extension angle at any time after surgery. When the patient’s preoperative diagnosis, namely OA and RA, were compared, there was no difference in the flexion angle of the knee before
surgery. Postoperatively, the flexion arcs were 114.48 in OA and 124.48 in RA at 3 months after surgery, 117.18 in OA and 130.08 in RA at 1 year, and 116.68 in OA and 132.58 in RA at 2 years after surgery, respectively. At each follow-up, the flexion angles were significantly greater in the RA group postoperatively ( P = .007 at 3 months, P = .008 at 1 year, P = .024 at 2 years after surgery). There were no differences in the extension angles of the knees between OA and RA postoperative patients. The preoperative flexion angles had a weak positive correlation with the flexion angles at 3 months (r = 0.27, P = .022) and 1 year (r = 0.32, P = .007) after surgery, but at 2 years after surgery, there was no correlation. The preoperative tibiofemoral varus/valgus angle was classified as neutral in 15 knees (10%), varus in 118 knees (78.7%), and valgus in 17 knees (11.3%). Although there was no statistical correlation between preoperative tibiofemoral varus/valgus angle and postoperative range of motion of the knee(r = 0.02 and P = .91 at 3 months, r = 0.01 and P = .92 at 1 year, and r = 0.03 and P = .86 at 2 years after surgery), PCL-sacrificing implants were more often selected for knees with greater deformities (ie, N158) than knees than the other 2 implant designs (ie, CR and MB) (Fig. 2). There was no correlation between the lateral inclination angle of patella and the postoperative range of motion of the knee (r = 0.16 and P = .29 at 3 months, r = 0.18 and P = .24 at 1 year, and r = 0.08 and P = .60 at 2 years after surgery). There was also no correlation between the lateral displacement of patella and the postoperative range of motion of the knee (r = 0.01 and P = .97 at 3 months, r = 0.01 and P = .97 at 1 year, and r = 0.05 and P = .75 at 2 years after surgery). Postoperative Flexion Angle [degree]
retaining group but were part of a multicenter randomized trial. The operation was performed through a medial parapatellar approach in all cases. All components were cemented. The patella was resurfaced in 211 knees (96.3%) and not resurfaced in 8 knees (3.7%). A lateral retinacular release was performed in 7 knees (3.2%). In postoperative physical therapy, walking with partial to full weight bearing began the day after surgery. Patients were discharged 5 days after surgery. Outpatient physiotherapy was prescribed in all patients. A continuous passive motion machine was not used after surgery.
150 140 130 120 110 100 90 80 70 60 -30 -20 -10 0 10 20 30 Preoperative Tibiofemoral Varus/Valgus Angle [degree] CR MB PS
Fig. 2. Relationship between preoperative tibiofemoral varus/valgus angles and postoperative flexion angles.
Range of Motion After Contemporary Total Knee Arthroplasty ! Kotani et al
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Relationship Between the Component Alignment Angles and the Postoperative Range of Motion of the Knee Joint Mean values for a and b angles were 95.48 F 2.38 and 89.18 F 1.68, respectively. The postoperative tibiofemoral varus/valgus angle calculated from these angles (3608 a b) was between 1678 and 1828, averaging 175.58 F 2.88. The mean c and d angles were 0.88 F 3.18 and 85.88 F 2.58, respectively. The postoperative lateral alignment of the knee calculated from these angles (c + 908 d) was between 68 and 178, averaging 4.98 F 4.28. Concerning the patellar component, the patella component tilt angle was 7.88 F 5.58 on average, and the patella component deviation ratio was 49.4% F 4.3% on average (Table 1). There was no correlation between the positioning of the femoral and tibial components, postoperative tibiofemoral varus/valgus alignment angles, or postoperative lateral alignment of the knee and the postoperative range of motion of the knee. Relationship Between the Size of the Femoral Component and Postoperative Range of Motion of the Knee Joint The size of the femoral components tended to be greater in males and smaller in females (Fig. 3). The postoperative range of motion was compared by femoral component sizes stratified into a small-sized group (sizes 3 and 4, group S), a medium-sized group (sizes 5 and 6, group M), and a large-sized group (sizes 7 and 8, group L). There were no significant differences in the preoperative range of motion of the knees among these 3 groups. At 3 months and 1 year after surgery, the flexion arcs of the knees in group L were significantly greater by 58 (at 3 months) to 78 (at 1 year)
Fig. 3. Femoral component size distribution.
compared to the other 2 groups (Fig. 4). There were no significant differences in the flexion arcs among these 3 groups 2 years after surgery. There were no significant differences in the extension angles of the knees among the groups at any time after surgery. Relationship Between Device Models and Postoperative Range of Motion of the Knee Joint There was no significant difference in the preoperative flexion or extension ranges of motion among the 3 component designs of CR, PS, and MB (Fig. 5). At 3 months and at 1 year after surgery, [degree] 135
*
130
*
Mean 95.4 89.1 4.5
2.3 1.6 2.8
Min 90.0 83.5 2.0
Max 105.0 94.0 13.0
120 115 S M L
110 105 100
* P < .05
95
0.8 85.8 4.9
3.1 2.5 4.2
10.0 79.0 6.0
11.5 94.0 17.0
7.8
5.5
11.0
56.0
49.4
4.3
37.3
63.2
Extension
a Angle (degree) b Angle (degree) Postoperative tibiofemoral varus/ valgus angle (degree) c Angle (degree) d Angle (degree) Postoperative lateral alignment of the knee (degree) Patellar component tilt (degree) Patellar component deviation (%)
SD
Flexion
125
Table 1. Component Alignment Angles
15 10 5 0 -5
Pre-Ope
3M
1Y
2Y
Fig. 4. Relationship between femoral component size and range of motion.
854 The Journal of Arthroplasty Vol. 20 No. 7 October 2005
Flexion
[degree] 135 130 125 120 115 110 105 100 95
*
*
CR MB PS
Extension
90
* p<0.05
15 10 5 0 -5
Pre-Ope
3M
1Y
2Y
Fig. 5. Relationship between TKA design and range of motion.
the flexion angles in the PS group were significantly greater by 48 (at 3 months) to 68 (at 1 year) compared to the other 2 groups. There were no significant differences in the flexion ranges of motion among these 3 groups 2 years after surgery. There were no significant differences in the extension ranges of motion among the 3 groups at any time after surgery.
Discussion Postoperative range of motion is an important determinant of patient satisfaction after TKA. In daily life, activities such as a deep knee bend require knee flexion of 1108 or more. If a flexion arc of 1108 or more is achieved, improvement in the performance of daily activities can be expected. A number of previous reports have described factors that affect the range of motion after total knee joint arthroplasty [4,5,9 -12]. These include proper ligament balancing, management of the PCL, and flexion of the knee at the time of the wound closure [2,9,13]. Postoperative physiotherapy has also been demonstrated to be an important factor in achieving knee range of motion [13]. The purpose of this single center, single surgeon study was to evaluate these factors using a single contemporary knee arthroplasty design. Our study agrees with the report of Schurman et al [7], that sex did not appear to be an important factor affecting knee joint range of motion. The influence of age on postoperative knee range of motion remains controversial. Horikawa et al
[14] found that preoperative range of motion was not correlated with age, but that there was a weak correlation between postoperative range of motion and age (r = 0.277, P b .05). Schurman et al [8] divided 25 patients with preoperative range of motion of less than 788 into 2 groups: one group of patients 62 years or younger and a second group older than 63 years. The younger group showed a mean postoperative range of motion of 838, whereas the older group had a mean value of 1008, demonstrating that the age was a factor. In contrast, Harvey et al [9] and Anouchi et al [1] reported no correlation between age and postoperative knee range of motion. In our study, we also found no age-related effect on postoperative knee range of motion. There are some reports indicating that obesity has an adverse effect on postoperative knee range of motion due to soft tissue impingement between the femur and the tibia, which restricts flexion of the knee [11,15]. Shoji et al [11] concluded that obese patients accounted for a larger percentage of the patients with a poor range of motion. Lizaur et al [15] reported that BMI was significantly correlated (r = 0.25, P = .023) with postoperative range of motion. In our study, BMI was not strongly correlated with postoperative range of motion. Regarding preoperative diagnosis, a number of comparative studies of OA and RA have been conducted [7- 9,12,16,17]. Most, but not all of these studies, have reported a greater improvement rate in range of motion in the RA group who had a poorer preoperative range of motion. In our study, there was no difference in preoperative range of motion between the OA and RA groups. Postoperatively, the RA group showed a significantly greater range of motion in agreement with most published studies. From the standpoint of preoperative range of motion, most reports have demonstrated that a greater postoperative flexion arc was achieved in patients with greater preoperative range of motion of the knee joint. Kurosaka et al [13] reported that preoperative range of motion of the knee joint was the most important factor. This investigation did find that patients with poor preoperative flexion showed greater improvement than those with good preoperative flexion. Our study results demonstrated some positive correlation between preoperative flexion and postoperative flexion at 3 months and 1 year, but no evident correlation at 2 years after surgery. Mean preoperative range of motion of the subjects included in our study was 1158, which was considerably greater than that previously
Range of Motion After Contemporary Total Knee Arthroplasty ! Kotani et al
reported, and this may be a reason for the absence of a significant correlation. In our study, preoperative tibiofemoral deformity was not found to be a significant factor affecting postoperative range of motion as was found by Kawamura and Bourne [18] and Shurman et al [8]. This may be due to the fact that PCLsubstituting implants were selected for patients with greater deformity. To demonstrate the relation between preoperative patellar tracking and postoperative flexion, the correlation between the preoperative lateral tilt and lateral displacement of the patella was investigated [19,20]. As far as we know, there is no study report available in the literature regarding the relationship between patellar tracking and postoperative flexion. Our study results showed no correlation between them. We performed the arthroplasty of patellar component in 211 of 219 patients, and excellent patellar tracking was achieved with a mean patellar component tilt of 7.88 F 5.58 and a mean patella component deviation of 49.4% F 4.3%. This may be considered the reason for the absence of a correlation. Controversy exists with regards the effect of femoral and tibial implant positioning on eventual TKA range of motion. Horikawa et al [14], Walker and Garg [21], and Schurman et al [7] are not in agreement. The use of modern instrumentation that accurately positions the femoral, tibial, and patellar components may have rendered implant positioning a nonissue in this study. Our study was not consistent with the finding of Kurosaka et al [13] that range of motion was affected by femoral component size. Our results suggest that the femoral component size did not influence final knee range of motion after TKA. A number of previous studies have reported on the comparison of postoperative range of motion between PCL-preserving and PCL-sacrificing total knee arthroplasties. Andriacchi et al [22] reported that preservation of PCL induced rollback of femur and consequently increased postoperative flexion. On the other hand, Dennis et al [2] reported that it was possible to maintain more normal kinematics of knee by using the post/cam mechanism of PCL-sacrificing implants. Becker et al [23] investigated 30 patients with a PCL-preserving design in one knee and a PCL-sacrificing design in the other knee. His group reported that the PCLsacrificing design had poor preoperative range of motion but achieved better postoperative flexion compared with the PCL-preserving implants. In our study, the range of motion of PCL-sacrificing TKAs was significantly greater than with PCL-
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preserving and mobile bearing TKAs up to 1 year postoperatively, but no differences were noted at 2 years after surgery.
References 1. Anouchi YS, McShane M, Kelly Jr F, et al. Range of motion in total knee replacement. Clin Orthop 1996;331:87. 2. Dennis DA, Komistek RD, Stiehl JB, et al. Range of motion after total knee arthroplasty: the effect of implant design and weight bearing conditions. J Arthroplasty 1998;13:748. 3. Dennis DA, et al. In vivo knee kinematics derived using an inverse perspective technique. Clin Orthop 1996;331:107. 4. Maloney WJ, Schurman DJ. The effects of implant design on range of motion after total knee arthroplasty. Total condylar versus posterior stabilized total condylar designs. Clin Orthop 1992; 278:147. 5. Parsley BS, Engh GA, Dwyer KA. Preoperative flexion. Does it influence postoperative flexion after posterior - cruciate – retaining total knee arthroplasty? Clin Orthop 1992;275:204. 6. Menke W, Schmitz B, Salm S. Range of motion after total knee arthroplasty. Arch Orthop Trauma Surg 1992;III:280. 7. Schurman DJ, Parker JN, Ornstein D. Total condylar knee replacement. J Bone Joint Surg 1985; 67A:1006. 8. Schurman DJ, Matityahu A, Good SB, et al. Prediction of postoperative knee flexion in InsallBurstein II total knee arthroplasty. Clin Orthop 1998;353:175. 9. Harvey IA, Barry K, Kirby SPJ, et al. Factors affecting the range of movement of total knee arthroplasty. J Bone Joint Surg Br 1993;75:950. 10. Ritter MA, Campbell ED. Effect of range of motion on the success of a total knee arthroplasty. J Arthroplasty 1987;2:95. 11. Shoji H, Solomonow M, Yoshino S, et al. Factors affecting postoperative flexion in total knee arthroplasty. Orthopedics 1990;13:643. 12. Tew M, Forster IW, Wallace WA. Effect of total knee arthroplasty on maximal flexion. Clin Orthop 1989; 247:168. 13. Kurosaka M, Yoshiya S, Mizuno K, et al. Maximizing flexion after total knee arthroplasty. J Arthroplasty 2002;17:59. 14. Horikawa K, Wakabayashi H, Uchida A, et al. Factors influencing the postoperative range of motion after total knee arthroplasty. J Chubu Seisai 1999:717. 15. Lizaur A, Marco L, Cebrian R. Preoperative factors influencing the range of movement after total knee arthroplasty for severe osteoarthritis. J Bone Joint Surg Br 1997;79:629.
856 The Journal of Arthroplasty Vol. 20 No. 7 October 2005 16. Ritter MA, Stringer EA. Predictive range of motion after total knee replacement. Clin Orthop 1979; 143:115. 17. Tew M, Forster IWF. Effect of knee replacement on flexion deformity. J Bone Joint Surg 1987;69B:395. 18. Kawamura H, Bourne RB. Factors affecting range of flexion after total knee arthroplasty. J Orthop Sci 2001;6:248. 19. Chew JTH, Stewart NJ, Hanssen AD, et al. Differences in patellar tracking and knee kinematics among three different total knee designs. Clin Orthop 1997;345:87.
20. Gomes LSM, Bechtold JE, Gustilo RB. Patellar prosthesis position in total knee arthroplasty. Clin Orthop 1988;236:72. 21. Walker PS, Garg A. Range of motion in total knee arthroplasty. A computer analysis. Clin Orthop 1991;262:227. 22. Andriacchi TP, et al. Retention of the posterior cruciate in total knee arthroplasty. J Arthroplasty 1998:13. 23. Becker MW, Insall JN, Faris PM. Bilateral total knee arthroplasty. One cruciate retaining and one cruciate substituting. Clin Orthop 1991;271:122.