A comparison of 2 continuous passive motion protocols after total knee arthroplasty: a controlled and randomized study

Effect of continuous passive motion (CPM) protocols on outcomes after total knee arthroplasty. In this prospective randomized controlled study, 147 patients were assigned to 1 of 3 treatment groups: CPM from 0 degrees to 40 degrees and increased by 10 degrees per day, CPM from 90 degrees to 50 degrees (early flexion) and gradually progressed into full extension over a 3-day period, and a no-CPM group. The CPM was administered twice a day for 3 hours over a 5-day period. All patients participated in the same postoperative physiotherapy program. Patients were assessed preoperatively, day 5, 3 months, and 1 year postoperatively. The early flexion group had significantly more range of flexion than both the standard and control groups at day 5. There was no significant difference between the groups for any other variable tested at any time frame. Key words: total knee arthroplasty, CPM, rehabilitation, outcomes.     

The role of continuous passive motion following total knee arthroplasty

A retrospective study of 94 knees with postoperative continuous passive motion (CPM) therapy was compared with a control group of 116 knees with no postoperative CPM following kinematic condylar total knee arthroplasty (TKA) performed in 1983. The diagnoses were similar in both groups, with osteoarthritis in 167 knees, rheumatoid arthritis in 34 knees, osteonecrosis in four knees, traumatic arthritis in four knees, and psoriatic arthritis in one knee. Average flexion at hospital discharge was 87.7 degrees in the control group and 90.2 degrees in the CPM group (p less than 0.02). Seventy-four percent of the CPM group and 60% of the control group had achieved 90 degrees of flexion by the time of hospital discharge. The number of days to achieve 90 degrees averaged 10.3 in the control group and 7.7 in the CPM group (p less than 0.001). There was no significant difference in flexion at two or three months or at one year after operation between the two groups. Five knees in the control group and one in the CPM group required manipulation. The duration of hospitalization was not significantly different between the two groups. Hemoglobin levels, operative blood loss, and transfusion requirements were not significantly different. Patients with CPM following TKA achieve motion earlier than those without CPM, but ultimate motion and complications are not affected.     

Continuous passive motion compared to active physical therapy after knee arthroplast:Similar hospitalization times in a randomized study of 68 patients

68 consecutive patients who had primary knee arthroplasties because of arthrosis were randomized to postoperative continuous passive motion (CPM) or active physical therapy (APT). Rehabilitation in both groups was initiated on the first postoperative day. The CPM group sustained less postoperative knee swelling with more rapid initial improvement in knee flexion than did the APT group, but there were no differences between the groups in knee flexion at discharge. Postoperative pain rating and hospitalization times were similar in the two groups.     

Continuous passive motion after total knee arthroplasty

Sixty-two patients undergoing primary total knee arthroplasty were studied prospectively. There were 42 patients in whom continuous passive motion (CPM) was used after surgery and 20 controls. The two groups were comparable with respect to age, diagnosis, sex, weight, and preoperative deformity and motion. The mean length of time required for CPM patients to achieve 90 degrees of flexion (9.1 days) was shorter than that for the control group (13.8 days). At the time of discharge from the hospital, however, there was no significant difference between the groups in amount of either flexion or extension. All patients had venograms performed after arthroplasty; the incidence of positive studies indicating thrombophlebitis was 45% in CPM patients and 75% in controls. These data demonstrate that CPM after knee arthroplasty enables patients to recover motion more quickly and affords some protection against deep vein thrombosis.     

Anteroposterior stability in posterior cruciate ligament-retaining total knee arthroplasty

Anteroposterior stability was evaluated using a KT-2000 arthrometer in 18 patients (21 knees) continuously for up to 5 years after posterior cruciate ligament-retaining total knee arthroplasty. The Knee Society score, functional score, and the maximum flexion angle did not change significantly during the postoperative period. The mean anteroposterior displacement of all joints studied at both 30 degrees and 75 degrees of flexion did not change significantly during the 5-year period of observation, but 4 individual knees did exhibit increases in anteroposterior displacement of 3 mm or more. One of the 4 knees exhibited osteolysis beneath the tibial component. Three of these knees had undergone high tibial osteotomy at some time before the total knee arthroplasty.     

Improved clinical outcomes after high-flexion total knee arthroplasty: a 5-year follow-up study

The purpose of this study was to determine if high-flexion total knee arthroplasty resulted in improved outcomes compared with conventional total knee arthroplasty. This was a prospective, double-blind, randomized controlled trial involving 76 patients over 5 years. We compared the postoperative flexion range, Knee Society scores, Oxford knee scores, and SF-36 scores between 2 groups. The high-flexion group was able to achieve a significant sustainable increase in postoperative knee flexion angle; and this correlated to a significant improvement in the General Health, Vitality, and Physical Functioning scales of SF-36 at 5 years postoperatively. Our results signify that high-flexion total knee arthroplasty has additional benefits to the quality of life in patients who require higher degrees of knee flexion in their activities of daily living.     

Association of increased knee flexion and patella clunk syndrome after mini-subvastus total knee arthroplasty

This study reviewed 747 consecutive posterior stabilized total knee arthroplasty (TKA) to explain the increased incidence of patella clunk syndrome that occurred when the surgeon switched from a medial parapatellar arthrotomy to a mini-subvastus (MIS) TKA technique. The incidence of patella clunk syndrome increased with increased postoperative knee flexion. Six weeks after surgery, knees that developed patella clunk had a mean flexion of 124 degrees vs 117 degrees for knees that did not develop this syndrome (P = .016). As the MIS approach resulted in increased knee flexion, this approach was indirectly associated with the increased incidence of patella clunk. Knee flexion at 6 weeks postoperatively was 117 degrees for the MIS knees vs 108 degrees for traditional medial parapatellar arthrotomy knees (P < .001). The effect of increased knee flexion achieved with the MIS approach, which resulted in an increase in patella clunk, was mitigated by using a new posterior stabilized femoral component designed to minimize soft tissue entrapment.     

Biomechanics of posterior-substituting total knee arthroplasty: an in vitro study

The cam-spine system in posterior-substituting total knee arthroplasty was designed to improve posterior stability and to increase posterior femoral translation (rollback). Little is known on its effectiveness in the restoration of femoral rollback under functional loads. In the current study, the effect of cam-spine engagement on knee motion under simulated muscle loads was investigated using knees from cadavers. The translations of the lateral and medial femoral condyles of the knee before and after total knee arthroplasty were compared from 0 degrees to 120 degrees flexion. Cam-spine contact forces were measured under the same muscle loads. The posterior translations of both femoral condyles in the total knee arthroplasty were significantly lower than that of the native knee beyond full extension. Cam-spine engagement occurred between 60 degrees and 90 degrees flexion followed by an increase in posterior translation of both femoral condyles. However, the resultant femoral translation of the total knee arthroplasty was still lower than that of the native knee from 90 degrees to 120 degrees flexion. Knee motion after cam-spine engagement was independent of muscle loads, indicating the importance of the cam-spine mechanism at high flexion angles. Decreased posterior translation of both femoral condyles after total knee arthroplasty may be a limiting factor at high flexion.     

Home continuous passive motion machine versus professional physical therapy following total knee replacement

A vigorous rehabilitation program following discharge from the hospital is necessary for patients having a total knee arthroplasty to maintain and improve range of motion and function. To compare the effectiveness of the continuous passive motion (CPM) machine as a home therapy program versus professional physical therapy, a prospective, comparative, randomized clinical study of 103 consecutive primary total knee arthroplasties in 80 patients (23 bilateral) was performed. The CPM group consisted of 37 patients (49 knees), and the physical therapy group consisted of 43 patients (54 knees). At 2 weeks, knee flexion was similar in the two groups, but a flexion contracture was noted in the CPM group (4.2°). This difference is felt by the authors to be clinically insignificant. At 6 months, there were no differences in knee scores, knee flexion, presence of flexion contracture, or extensor lag between the two groups. The cost for the CPM machine group was $10,582 ($286 per patient), and the cost for professional therapy was $23,994 ($558 per patient). We conclude that the CPM machine after the hospital discharge of patients having total knee replacement is an adequate rehabilitation alternative with lower cost and with no difference in results compared with professional therapy.     

Predicting range of motion after revision total knee arthroplasty: clustering and log-linear regression analyses

The purpose of this study was to determine which variables affected the range of motion following revision total knee arthroplasty. These variables included preoperative flexion, intraoperative flexion, preoperative alignment, patient demographics, type of posterior soft-tissue release, previous prosthesis type, and prosthesis type used for revision of 355 total knee arthroplasties. Clustering and log-linear regression analyses were used to determine which variables were significantly related to the postoperative flexion. The mean preoperative and postoperative flexion were 100.5 degrees and 104.6 degrees. Low preoperative (<103 degrees) and intraoperative flexion (<117 degrees), young age (<44 years), and constrained and hinged prosthesis types were associated with diminished flexion. Higher preoperative and intraoperative flexion resulted in higher postoperative flexion. When comparing the results of this study to the results of a similar study of primary total knee arthroplasties, flexion improved less following revision than following primary total knee arthroplasty.     

Manipulation after total knee arthroplasty

BACKGROUND: Following total knee arthroplasty, some patients who fail to achieve >90 degrees of flexion in the early perioperative period may be considered candidates for manipulation of the knee under anesthesia. The purpose of this study was to assess the outcomes of manipulation following total knee arthroplasty. METHODS: One hundred and thirteen knees in ninety patients underwent manipulation for postoperative flexion of < or =90 degrees at a mean of ten weeks after surgery. Flexion was measured with a goniometer prior to total knee arthroplasty, at the conclusion of the operative procedure, before manipulation, immediately after manipulation, at six months, and at one, three, and five years postoperatively. RESULTS: Eighty-one (90%) of the ninety patients achieved improvement of ultimate knee flexion following manipulation. The average flexion was 102 degrees prior to total knee arthroplasty, 111 degrees following skin closure, and 70 degrees before manipulation. The average improvement in flexion from the measurement made before manipulation to that recorded at the five-year follow-up was 35 degrees (p < 0.0001, paired t test). There was no significant difference in the mean improvement in flexion when patients who had manipulation within twelve weeks postoperatively were compared with those who had manipulation more than twelve weeks postoperatively. Patients who eventually underwent manipulation had significantly lower preoperative Knee Society pain scores (more pain) than those who had not had manipulation (p = 0.0027). CONCLUSIONS: Manipulation generally increases ultimate flexion following total knee arthroplasty. Patients with severe preoperative pain are more likely to require manipulation.     

The natural history of flexion contracture in total knee arthroplasty. A prospective study

A prospective study was carried out to document the natural history of flexion contractures of the knee after total knee arthroplasty (TKA). Thirty-five knees in 33 patients with TKA were followed for a mean duration of 55 weeks. In no case did the surgical procedure include excessive bony resection in order to correct a flexion contracture. Standard goniometric measurements were used to determine the knee flexion contractures preoperatively and postoperatively while the patient was anesthetized and at each successive follow-up visit. All preoperative and postoperative flexion contractures were less than 30 degrees. The mean fixed flexion deformity of the entire group preoperatively was 12.9 degrees; immediately postoperatively, 14.8 degrees; and at final follow-up, 2.9 degrees. No difference was found in the amount of flexion contracture present at final follow-up evaluation with respect to age or gender. The impression that fixed flexion contractures must be corrected at the time of arthroplasty has led to the intraoperative removal of excess bone from the distal femur and/or proximal tibia. The present findings indicate that knee flexion contractures can significantly improve after TKA. There appears to be little, if any indication for excessive removal of bone in an attempt to achieve intraoperative correction.     

Total knee arthroplasty after failed proximal tibial valgus osteotomy

The results of total knee arthroplasty were evaluated in 113 patients with gonarthrosis (14 patients with and 99 without prior operation with proximal tibial valgus osteotomy). There was no difference in the final result after follow-up periods of 4–9 years with respect to average Hospital for Special Surgery score, degree of knee flexion, and later knee revisions between the 14 osteotomized and 99 nonosteotomized patients. The average femorotibial angle did not differ between the groups; neither did the average wear of the tibial polyethylene. No difference was found in operative time, but a significantly greater blood loss and other postoperative complications were noted among the previously osteotomized group of patients, indicating a more complicated procedure for the knee arthroplasty operation compared with the nonosteotomized group of patients.     

Does Greater Knee Flexion Increase Patient Function and Satisfaction After Total Knee Arthroplasty?

The purpose of this study was to determine whether high flexion leads to improved benefits in patient satisfaction, perception, and function after total knee arthroplasty (TKA). Data were collected on 122 primary TKAs. Patients completed a Total Knee Function Questionnaire. Knees were classified as low (≤110°), mid (111°-130°), or high flexion (>130°). Correlation between knee flexion and satisfaction was not statistically significant. Increased knee flexion had a significant positive association with achievement of expectations, restoration of a “normal” knee, and functional improvement. In conclusion, although the degree of postoperative knee flexion did not affect patient satisfaction, it did influence fulfillment of expectations, functional ability, and knee perception. This suggests that increased knee flexion, particularly more than 130°, may lead to improved outcomes after TKA.     

Patellofemoral joint after total knee arthroplasty: Effect on contact area and contact stress

Compressive contact stress between the patella and the anterior femur and between the quadriceps tendon and anterior femur was measured before and after total knee arthroplasty in 5 cadaver knee specimens using a digital electronic sensor. Contact stresses were measured in the normal knee and after total knee arthroplasty with an unresurfaced patella, a dome-shaped patella, and a conforming patella. Patellofemoral contact stresses did not change significantly after total knee arthroplasty when the patella was not resurfaced, but they increased significantly after the patella was resurfaced with both the dome-shaped and the conforming components. The conforming patella had the highest contact stresses because it tilted at flexion angles greater than 90° and applied load to a small area on the superior portion of the patellar component. The conforming patella markedly decreased tendofemoral contact force because the thicker superior pole of the patella tented the quadriceps tendon at flexion angles greater than 120°. This further increased patellofemoral contact force in deep knee flexion.     

Comparison of mobile-bearing and fixed-bearing total knee arthroplasty: a prospective randomized study

The purpose of this prospective randomized study was to compare the postoperative recovery and early results of 2 groups of patients undergoing total knee arthroplasty: 107 patients received an established fixed-bearing posterior-stabilized prosthesis (Legacy Posterior Stabilized [LPS]), and 103 patients the meniscal-bearing prosthesis (Meniscal Bearing Knee [MBK]). Surgical procedures were the same for both groups except for posterior cruciate ligament management, which was sacrificed in the LPS group and spared but completely released from the tibia in the MBK group. At an average follow-up of 36 months, knee, function, and patellar scores were comparable in both groups. The LPS group showed a significantly higher maximum flexion than the MBK group (112 degrees vs 108 degrees). Using a fixed-bearing or a mobile-bearing design did not seem to influence the short-term recovery and early results after knee arthroplasty. Key words: total knee arthroplasty, mobile bearing, knee prosthesis, meniscal-bearing knee, posterior stabilized, prospective randomized.     

Blood salvage in total hip and knee arthroplasty in a community hospital: a retrospective study

PURPOSES: To assess the results of postoperative and intra-operative blood salvage in patients undergoing total knee and hip arthroplasty, respectively, and to determine if both methods of blood salvage reduce allogeneic transfusion. METHODS: Of 229 patients who attempted blood salvage, 114 of 152 patients who underwent total knee arthroplasty received the salvaged blood postoperatively, 35 of 77 patients who underwent total hip arthroplasty received the salvaged blood intra-operatively. Various data were collected to assess whether certain factors resulted in autologous and/or allogeneic blood transfusions. RESULTS: Patients that received postoperative salvaged blood after total knee arthroplasty generally had higher postoperative levels of haemoglobin and haematocrit compared to those who did not. Patients with autologous blood transfusion following cemented knee surgery were less likely to require allogeneic blood transfusion. For hip arthroplasty patients, postoperative levels of haemoglobin and haematocrit were similar in both groups who received and did not receive salvaged blood. Lower preoperative haemoglobin and haematocrit levels correlated with a greater likelihood of autologous and/or allogeneic blood transfusion for both knee and hip arthroplasty patients. CONCLUSIONS: Although total knee arthroplasty patients who received salvaged blood had higher haemoglobin levels on the first postoperative day, the receipt of salvaged blood did not significantly reduce the incidence of allogeneic blood transfusion, because salvaged blood was a kind of blood loss. However, reinfusion of salvaged blood may reduce the number of units of allogeneic blood used. Given the short supply of allogeneic blood and its risks of transmitting disease, intra-operative and postoperative blood salvage carries clear advantages.     

Influence of hip position on knee flexion angle in patients undergoing total knee arthroplasty

The influence of hip position on knee flexion angle before total knee arthroplasty (TKA) and that after TKA were investigated and compared. Sixty-six patients (70 knees) with osteoarthritis who were undergoing TKA were examined using lateral radiographs of maximum knee flexion angle with the hip joint at 0 degrees extension and 90 degrees flexion. The postoperative rate of decrease in knee flexion angle caused by hip extension was significantly larger compared with the value before surgery. The preoperative rate of decrease in knee flexion angle caused by hip extension showed strong inverse correlation with the preoperative and postoperative knee flexion angle ratio. In conclusion, tightness of the extensor mechanism is present in all knees undergoing TKA and especially has a strong influence on the postoperative flexion angle of the knee.     

The role of flexion contracture on outcomes in primary total knee arthroplasty

This study examined the role that flexion contracture plays in postoperative outcomes after total knee arthroplasty using a retrospective database review. The relationships between preoperative and postoperative knee extension, walking ability, stair climbing ability, Knee Society scores, pain scores, and knee function scores were studied in 5,622 knees. A preoperative flexion contracture was associated with an increased incidence of a persistent postoperative flexion deformity. A postoperative flexion contracture was associated with poorer postoperative results. Furthermore, a postoperative hyperextension deformity of greater than 10 degrees was associated with an increased risk of suboptimal pain and Knee Society scores. Knee extension deformities play a substantial detrimental role in the functional outcome of primary total knee arthroplasty.     

Efficacy of Periarticular Injection of Bupivacaine,Fentanyl, and Methylprednisolone in Total Knee Arthroplasty : A Prospective,Randomized Trial

We evaluated the efficacy of periarticular infiltration of corticosteroid, opioid, and a local anesthetic by comparing pain scores, knee flexion, and quadriceps function on the day of surgery, first postoperative day, day of discharge, and 2 and 4 weeks after surgery between the infiltrated and the noninfiltrated knee in 40 patients undergoing simultaneous bilateral computer-assisted total knee arthroplasty who were randomized to receive the injection in the right or left knee. In comparison to the noninfiltrated side, the infiltrated knee showed significantly lower pain scores, significantly greater active flexion up to 4 weeks, and superior quadriceps recovery up to 2 weeks after surgery. This simple and inexpensive technique can significantly reduce pain and hasten functional recovery in the first month after total knee arthroplasty.