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Year : 2005  |  Volume : 39  |  Issue : 1  |  Page : 14-20
Unilateral vs one stage bilateral total knee replacement in rheumatoid and osteoarthritis - A comparative study

Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India

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Background : A controversy exists regarding simultaneous or staged bilateral total knee replacement.
Methods: Fifty patients undergoing simultaneous bilateral and 50 undergoing unilateral total knee arthroplasty were evaluated prospectively to compare the clinical, radiological results and complication rates. Eighty-four patients belonged to ASA category II or III preoperatively. The study included a high proportion of rheumatoid patients and osteoarthritis patients with severe deformities.
Results: Bilateral group had greater blood loss and required more blood transfusion, but there was no difference in requirement of postoperative intensive care and the complication rates. Rheumatoid knees had lower pre and postoperative knee score and functional score as compared to osteoarthritic knees. Morbidity and mortality of one stage bilateral knee replacement was no greater than unilateral operation.
Conclusion: Simultaneous bilateral knee replacement in younger patients with advanced rheumatoid arthritis is safe and effective

Keywords: Arthroplasty; Knee; Simultaneous; Bilateral; Unilateral.

How to cite this article:
Kiran E K, Malhotra R, Bhan S. Unilateral vs one stage bilateral total knee replacement in rheumatoid and osteoarthritis - A comparative study. Indian J Orthop 2005;39:14-20

How to cite this URL:
Kiran E K, Malhotra R, Bhan S. Unilateral vs one stage bilateral total knee replacement in rheumatoid and osteoarthritis - A comparative study. Indian J Orthop [serial online] 2005 [cited 2019 Sep 18];39:14-20. Available from:

   Introduction Top

Total knee replacement has now become a well­established surgical procedure with very high rate of success in restoration of function and correction of deformity of severely arthritic knees. Frequently patients present with severe bilateral knee arthropathy in which replacement of one joint will not improve the functional outcome. In such situation bilateral knee replacement is essential. There have been numerous studies documenting feasibility of one stage bilateral total knee replacement [1],[2],[3],[4],[5],[6],[7],[8],[9],[10] . Reduction in hospitalization time, total cost and early rehabilitation are the main advantages of bilateral simultaneous total knee replacement. Many studies have shown that overall clinical and radiological outcomes are similar in the simultaneous and staged bilateral total replacement groups [1],[4],[11],[12], though there is some controversy as to the increased risk of medical complications [13] . Most studies on feasibility of one stage bilateral total knee replacement have come from western centers on mainly osteoarthritis patients who had lesser degree of deformity and degeneration and were in good general health. In our practice patients opt for major surgery like total knee replacement when joint degeneration and deformity are so far advanced that even walking becomes difficult. Rheumatoid knees are a major segment of all total knee replacements done at our institution accounting for sixty percent of cases.

   Patients and Methods Top

This prospective study was undertaken from January 1996 to December 1999 to evaluate the clinical and radiological results of one stage bilateral and unilateral total knee arthroplasty in comparable number of rheumatoid and osteoarthritis patients who had advanced degeneration and severe deformities, to study the complication rates including systemic complications, ICU admission rates and local complications, and improvement in the Knee Society Scores (KSS) [14] and the postoperative radiological scores in the two groups. The mean improvement in the KSS (knee) and KSS (function) were compared in both the groups and also in the rheumatoid and osteoarthritis patients.

During the study period, patients who presented with symptomatic bicompartmental or tricompartmental arthritis of the knee and in whom conservative treatment had failed were offered total knee arthroplasty. Patients with bilateral disease were encouraged to have both knees replaced in single anesthesia time. Fifty consecutive patients having unilateral and fifty having simultaneous bilateral total knee arthroplasties under one anesthetic were included in the study. American Society of Anesthesiologists rating was used for preoperative assessment of anaesthetic risk in all patients [15] . The patients were classified into three groups based on American Knee Society (AKS) recommendation [Table - 1].

Technique: Regional anesthesia (combined spinal epidural anesthesia) was used in 74 patients. General anesthesia was used in the remaining patients. A single dose of preoperative antibiotic cefazolin 2 gram intravenously was administered half an hour prior to tourniquet inflation in all the patients. Antibiotic prophylaxis was continued postoperatively for three days in the dose of 1 gram eight hourly. Compression stockings and enoxeparin (40mg subcutaneously) for 10 days were used for antithrombotic prophylaxis.All operations were performed by the senior author (SB) in a laminar airflow theatre. Operations were done under tourniquet without exsanguinating the limb. In the bilateral group tourniquet inflation and operation on the second knee was begun only after tourniquet was released on the first knee. New drapes and second set of instruments were used for the second replacement. Medial parapatellar approach was used in all cases except four arthrofibrotic rheumatoid knees where quadriceps snip had to be done for exposure. Synovectomy and osteophyte excision was performed where indicated. Appropriate soft tissue release most commonly elevation of medial soft tissue sleeve for varus knees was done as required. Posterior cruciate ligament was sacrificed in all knees because of severe deformities. Intramedullary alignment for the femur and extramedullary alignment for the tibia were used. A posterior stabilized Insall Burstein II prosthesis was used with cement fixation for both femoral and tibial components. Patella was not replaced. One suction drain in each knee was kept before closure and compression dressing with knee immobilizer was applied. Post operatively, static quadriceps and ankle exercises were started early but more intensive physiotherapy and knee mobilization was started after removal of suction drain and knee immobilizer on the second day. Similar postoperative management protocol was followed in all patients including regaining flexion with gravity and active, assisted exercises without using continuous passive motion (CPM). An intra operative data form was used to record the tourniquet time, estimated blood loss and mean arterial oxygen saturation. A postoperative data form was used to record the postoperative blood loss, change in hemoglobin, transfusion requirement, complications, need for ICU admission and the mean hospital stay in both patient groups. Complications were defined as local, pertaining to the operative site, or systemic, relating to the patients' general medical condition. Pre and postoperative evaluation was done using Knee Society scoring system for knee score and function score [14] . The postoperative knee score and function score were recorded a minimum of 1 year following the arthroplasty by two registrars on an out patient basis. Radiologic assessment of component alignment was done using the criteria described by Lotke et al [16] .

Independent samples t-test was used to compare the clinical results of the unilateral and bilateral groups. The pre and postoperative knee scores in the rheumatoid and osteo­arthritis patients and the mean postoperative improvement were also compared separately. The demographic data and complication rates were analyzed using the chi-square test. A p value less than 0.05 was considered statistically significant. Statistical analysis was done using SPSS (Chicago, Illinois) software.

   Results Top

There was no statistically significant difference in the age and weight of the cohort of patients undergoing unilateral and bilateral replacements [Table - 1]. The demographic data of the patients is given in [Table - 2]. The rheumatoid patients had less body weight as compared to osteoarthritis (p<0.001). Sixty-four patients were ASA III (36 bilateral, 28 unilateral), 14 patients were ASA II (4 bilateral, 10 unilateral) and 22 patients were ASA I (10 bilateral, 12 unilateral) according to preoperative anesthetic evaluation [Table - 3]. Most of the patients had advanced disease and were in patient category B or C [Table - 4]. Most of the patients presented with advanced deformities, 106 knees had varus deformity (range 5o - 40o , mean 15o ), 84 knees had fixed flexion deformity (5o­40o , mean 16o), valgus deformity was seen in 22 knees (5-20o , mean 10o ) and biplanar deformity was seen in 72 knees. The mean preoperative arc of motion was 10o -110o in the osteoarthritic patients and 20o -95o in the rheumatoid group. Majority of the rheumatoid patients were very disabled prior to surgery with twenty seven (17 bilateral, 10 unilateral) being able to walk less than 50 meters and 9 (bilateral) were unable to walk due to bilateral severe flexion deformities. Forty-one of the fifty-four rheumatoid patients were on steroids preoperatively for a minimum period of 6 months. Fourteen of these were using methotrexate.The mean total tourniquet time was 161 minutes and 81 minutes for the bilateral and unilateral groups respectively. The mean blood loss in the bilateral group was nearly twice that of the unilateral group (p<0.001). The drop in the hemoglobin level four hours after surgery before blood transfusion was 64% higher in the bilateral group. More patients in the bilateral group required blood transfusion [Table - 5]. Autologous transfusion could not be used because the patients had low preoperative hemoglobin, which prevented them from predonating blood.

Complications: The incidence of pulmonary embolism or fat embolism in either group of patients was nil. Two patients of the bilateral group and one of the unilateral group required admission to intensive care unit for worsening of myocardial ischemia and hypothermia. Incidence of clinical and Doppler proven deep venous thrombosis (DVT), delayed wound healing, superficial and deep infection was similar in both groups [Table - 6]. None of the patients with bilateral replacements developed wound problem and infection on both the sides. No mortality was seen in either group. Knee mobilization was started on the second postoperative day and patients were allowed to walk with the aid of a walker as tolerated. Most patients in both groups began ambulation by the third postoperative day. All patients used a walking aid for 6 months following surgery. At least 80 degrees flexion was achieved in all patients of both the groups by the 14th postoperative day except in five rheumatoid knees with severe arthrofibrosis and preoperative flexion arc of 15o - 30o . The mean postoperative arc of motion in the unilateral group was 95.7 degrees (range 80o - 120o), while in the bilateral group this was 93.1 degrees (75-115 degrees). The rheumatoid knees had a mean post operative range of motion of 90o (range 75o­105o ) while the osteoarthritis knee had a mean post operative range of motion of 104o (range 90o - 120o).

Clinical results: The minimum follow up period was 2 years, with a mean follow up of four and a half years (range 2­7 years). The mean preoperative function score in the bilateral group was 32.1 and that of the unilateral group was 35.3 (p = 0.132). These improved postoperatively to 65.7 and 72.1 in the bilateral and unilateral groups respectively (p < 0.001). The mean knee scores improved from a preoperative value of 35.1 to 84.7 in the bilateral group and from 38.5 to 87.1 in the unilateral group [Table - 7]. Rheumatoid knees had lower knee and functional score to begin with and improved considerably from the preoperative status. Osteoarthritic knees had higher scores preoperatively and gained a better numerical score at final review. The overall quantum of improvement in the scores in the rheumatoid and osteoarthritis patients were similar [Table - 8].

Radiological results: Preoperative tibiofemoral alignment averaged 15o varus (range 5o to 40o ) in 106 knees and 10o valgus in 22 knees (range 5o -20o). At final follow up the mean tibiofemoral alignment was 4o valgus (range 0o - 9o valgus) in both groups of patients. The radiographic results are summarized in [Table - 9]. Radiologic scores were similar in unilateral and bilateral knee replacement groups.

   Discussion Top

There have been many studies on feasibility of one stage bilateral total knee replacement but only few studies had high proportion of rheumatoid patients [1],[2] and the severity of deformity has not been clear in these studies. The present study includes high proportion of rheumatoid patients having significant deformity, debilitating disease, low hemoglobin and a younger age group. Sixty-four patients in the study (36 bilateral and 28 unilateral) were rated ASA III preoperatively [15] . Since ASA assessment depends on severity of illness and physiologic reserve, it is not surprising that it would be a predictive of perioperative morbidity and mortality [17],[18]. Majority of our rheumatoid patients had severe systemic disease with functional impairment, were on steroids and other disease modifying medications. This study proves the safety and efficacy of one-stage bilateral knee replacements in young patients with advanced rheumatoid arthritis. Similar results were obtained in a cohort of patients with osteoarthritis. The use of combined spinal epidural anesthesia offers the additional advantages of continued postoperative pain relief, prevention of deep venous thrombosis and significant reduction of proximal thrombus formation [19],[20]. The choice of regional anesthesia was better especially for the severely debilitated rheumatoid patients who may not have tolerated general anesthesia as well. Total tourniquet time for one stage bilateral knee replacement in our study was 161 minutes as compared to 81 minutes for unilateral operation. Other studies [2] have reported twice tourniquet and operating time for simultaneous bilateral as compared to unilateral total knee arthroplasty. Two teams operating simultaneously on both knees [1] would reduce the total ischemia time but greatly increases the amount of tissue subjected to ischemia at one time. In the current study one tourniquet was deflated before the next was inflated thus increasing the total tourniquet time but greatly reducing the amount of tissue which remains ischemic at any given time and this may have been responsible for absence of ischemia related complications. Total blood loss in bilateral replacement in our study was nearly twice as compared to unilateral operation. Similar observations have been previously reported [2],[7],[9] . McLaughlin and Fischer [8] have reported that blood transfusion requirement of one stage bilateral knee replacement was about half as compared to if each knee was replaced during two different hospitalization periods eight months apart. Since patients especially of rheumatoid arthritis had low hemoglobin (mean 11.9 gram%) we have transfused blood when post operative hemoglobin was less than 8 gm% and tried to replace the blood lost up to that point in time. Due to this reason our blood transfusion requirement in one stage bilateral cases was about 64% higher than the unilateral cases. Patients because of low hemoglobin were not able to predonate blood for auto transfusion. This necessitated use of banked blood in 82% patients undergoing bilateral replacement and 66% of those undergoing unilateral replacement with its rare but important complications of disease transmission and occasionally transfusion reaction. This aspect is an area of great discretion and has to be decided by individual and patients depending on their own practice environment. Lane et al have reported nearly 3 times higher cardiopulmonary complications in simultaneous bilateral total knee replacement patients with arrhythmia being the commonest problem [21] . There were two patients (1 bilateral, 1unilateral group) in the present study that required admission to intensive care unit secondary to worsening of myocardial ischemia following surgery. However no difference was found between the cardiopulmonary complications seen in the two patient groups. The complication of deep venous thrombosis occurred less often in bilateral group if total number of operated knees is taken into consideration. Similar lower incidence of DVT in one stage bilateral knee arthroplasty has been reported earlier [8],[10],[22] . On the other hand some authors have reported increased incidence of DVT in bilateral cases [23] .

Dorr et al [24] have reported 12% incidence of fat embolism in one stage bilateral knee arthroplasty. With current method of using fluted rod and over drilled hole for the femur this incidence of fat embolism has been considerably minimized to the extent that some authors have concluded that the claim of increased danger of fat embolism in bilateral knee replacement is unsubstantiated [21],[23],[25] . There was no mortality during the whole period of follow up. Morrey et al [22] observed that higher incidence of mortality associated with two major surgeries under one anaesthetic has never been reported.There has always been concern about increased rate of infection and cross over infection in one stage bilateral total knee replacement. No crossover infection was noted in the present study. This can be attributed to the precaution taken by operating room staff, use of two separate sets of drapes and instruments and also to expedient performance of the operation [2],[8],[22],[26] . Transient peroneal nerve palsy occurred in two out of 100 knees replaced in the bilateral group and in one out of 50 knees in the unilateral replacement group. Two were probably related to correction of severe preoperative flexion valgus deformity in rheumatoid knees. One patient developed peroneal palsy owing to improper positioning of the limb post-operatively. The overall complication rates in the unilateral and bilateral groups were similar.The most consistent feature of one stage bilateral total knee replacement is approximately 5 days more hospitalization time [10],[13] and this was also true for our cases. The average duration of hospital stay in the two groups was 14 and 19 days respectively. This is much higher when compared to some of the western centers. Since patients often come from distant places (ours being a tertiary referral center) and home care facilities for physiotherapy and suture removal are not available all the patients were hospitalized at least till the suture removal, which accounted for the greater hospitalization time. Majority of the patients presenting for total knee arthroplasty in our set up do so only when they are so disabled by arthritis that walking becomes an ordeal. It is not surprising that many of them especially those with rheumatoid arthritis present with severe deformity and stiffness at the time of arthroplasty. Most of the patients regained at least 80 degrees flexion in both groups irrespective of the diagnosis. In five rheumatoid knees with arthrofibrosis the progress was slow as expected. Hardaker et al [1] have reported improvement in knee score from 44 to 81 and 47 to 78 in bilateral and unilateral knee replacement group respectively on patients of mixed diagnostic group including rheumatoid and osteoarthritis. Our cases showed similar improvement in knee score for both the one stage bilateral and unilateral replacement group. There was statistically significant (p<0.001) difference between the two groups in the Knee Society Score (function) attained post operatively. This is not surprising because the bilateral group comprised of greater proportion of rheumatoid patients with polyarticular involvement, with limitation of ambulatory capacity. The mean improvement in both groups after surgery was, however similar (p=0.059), even though the improvement was slightly better in the unilateral group. No difference was seen in the Knee Society scores (knee) between the unilateral and bilateral groups. There was statistically significant difference (p<0.001) between the pre and postoperative Knee Society Scores (knee) of rheumatoid and osteoarthritis knees. However, the mean postoperative improvement of the scores in the two groups was similar. This shows that although the final score attained by rheumatoid knees is lower than osteoarthritis knees, the quantum of improvement following arthroplasty remains similar. Also there is a limit of 45 to 50 points by which the knee score improves post operatively and the numerical value of score attained depends on the preoperative score. The radiological score was similar for both groups of patients. Perfect score of 100 points could be obtained in 4 of the unilateral and 6 of the bilateral knees showing that it is difficult to achieve a perfect score [16] . There have been very few prospective studies comparing results and complications of unilateral and bilateral total knee replacement. Most published studies are retrospective [8],[13],[27] and according to Lane et al[23] these are frequently inaccurate because they are heavily dependent on previous documentation, which may not be precise. In this respect our present prospective study of one stage bilateral knee replacement in large proportion of rheumatoid patients and in those with lower hemoglobin, physical fitness and mobility is valuable. The selection for bilateral replacement was based on whether both knees required replacement and preoperative co morbidities were not taken into consideration while making this decision. This helped us avoid selection bias. All the surgeries were performed by a single surgeon avoiding technique related bias. Both groups of patients had similar age and weight. Significant improvement in knee and function scores occurs postoperatively even in rheumatoid patients with poor preoperative scores. Our study has shown that one stage bilateral total knee replacement is a safe procedure.

   References Top

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Correspondence Address:
S Bhan
Department of Orthopedics, All India Institute of Medical Sciences, New Delhi 110029
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Source of Support: None, Conflict of Interest: None

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  [Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6], [Table - 7], [Table - 8], [Table - 9]


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