Mean Knee Society Function Score Research Articles

Bariatric Orthopaedics: Total Knee Arthroplasty in Super-obese Patients (BMI > 50 kg/m2). Survivorship and Complications

Some studies have suggested that patients who are super obese (BMI > 50 kg/m(2)) may have poorer outcomes and more frequent complications when undergoing TKA compared with those who have lower BMI, however, the literature on this is scant. The purpose of this study was to compare a group of super-obese patients undergoing TKA with a matched group of patients with BMI less than 30 kg/m(2) in terms of (1) implant survivorship, (2) complications, (3) functional parameters, and (4) intraoperative variables (including operative time and estimated blood loss). One-hundred one knees in 95 patients (21 men, 74 women) who had a minimum BMI of 50 kg/m(2) and who had undergone a primary TKA at one of the four high-volume institutions were compared with a group of patients who had a BMI less than 30 kg/m(2) who were matched by age, gender, preoperative clinical scores, and mean followup. End points evaluated by chart review included implant survivorship, medical and surgical complications, functional parameters (The Knee Society outcome scores and ROM), and intraoperative variables at a mean followup of 62 months (range, 36-85 months). With the numbers available, there were no differences in aseptic implant survivorship (94% versus 98%, p = 0.28), however, medical and surgical complication rates (14% versus 5%, OR: 3.1, 95% CI=1.07-8.9; p = 0.037) were significantly higher in the super-obese patients compared with the nonobese matching group, respectively. Super-obese patients also achieved lower mean Knee Society functional scores (82 versus 90 points, p = 0.004) and smaller gains in flexion arc ROM (14° versus 21°, p = 0.009); they also lost more blood during surgery and experienced longer surgical anesthesia times compared with the matched group, respectively. With the numbers available, we could not identify what might have been modest differences in implant survivorship, however, complications were more frequent and functional outcomes were significantly lower in super-obese patients. Other studies similarly have found inferior outcomes in this challenging group of patients. Our data may be considered pilot data for future prospective studies with longer followup.

Treatment of Schatzker Type V and VI Tibial Plateau Fractures Using a Midline Longitudinal Incision and Dual Plating

PurposeThe purpose of this study was to evaluate the results of the treatment of Schatzker type V and VI tibial plateau fractures using a midline longitudinal incision and dual-plate fixation.Materials and MethodsTen patients with Schatzker type V and VI tibial plateau fractures treated with a midline longitudinal incision and dual plating were analyzed. The patients were followed for a minimum of one year. Clinical outcomes were evaluated using range of motion, visual analogue scale (VAS) and Knee Society Score. Radiological outcomes were evaluated using the bony union time, medial proximal tibial angle (MPTA) and posterior proximal tibial angle (PPTA).ResultsThe mean VAS score was 2.2 points, and the mean Knee Society function score was 85 points at the final follow-up. The mean flexion contracture was 2.5° and the mean further flexion was 125°. It took an average of 4 months until bony union occurred. The mean MPTA and PPTA were 90.5° and 4.4°, respectively. There was one case of delayed wound healing, but no other complications were observed.ConclusionsThe treatment of Schatzker type V and VI tibial plateau fractures with a midline longitudinal incision and dual-plate fixation resulted in satisfactory clinical and radiological outcomes. This can be an option when treating Schatzker type V and VI tibial plateau fractures.

Seven-Year Survivorship and Functional Outcomes of the High-Flexion Vanguard Complete Knee System

Certain recreational, cultural, occupational, and religious practices may require knee flexion exceeding typical daily living activity needs. Some total knee prostheses mechanically accommodate high flexion to help meet such demands, e.g., the Vanguard knee (Biomet, Inc., Warsaw, IN) which can mechanically achieve 140°-145°. This multicenter, prospective clinical study of 957 Vanguard knees (865 patients) examined mid-term outcomes. The Kaplan-Meier survivorship estimate was 97.8% (95% CI: 96.5-98.7%) at 7.0 years. For patients with ≥ 2-year follow-up (n=627), mean peak flexion increased from 116.8° to 124.8° (P<0.001). For knees with pre-operative flexion of <95°, 95°-105°, and >105°, the mean increases were 27.8°, 22.0°, and 3.6°, respectively. Mean Knee Society Knee and Function scores increased from 45.9 and 45.5 points to 92.0 and 73.8 points, respectively (P<0.001).

Treatment of Large Bone Defects With Trabecular Metal Cones in Revision Total Knee Arthroplasty

The early term results of 29 cases of revision total knee arthroplasty using highly porous trabecular metal cone implants for femoral and tibial major bone deficit reconstruction (Anderson Orthopedic Research Institute classification type 2B and 3) have been prospectively analyzed. Indications for revision surgery included: aseptic loosening/wear, staged reimplantation after infection, as well as periprosthetic fracture. At an average follow-up of 33 months (range, 13-73 months) the mean Knee Society Score and functional score statistically improved. Radiological follow-up revealed no evidence of loosening or migration of the constructs. No evidence of complications was noted in correlation with the use of trabecular metal cones. This study supports evidence that trabecular metal cones are an efficient and effective option for dealing with significant bone deficits and obtaining stable biological fixation in revision total knee arthroplasty.

Posterior femoral translation in medial pivot total knee arthroplasty of posterior cruciate ligament retaining type

PurposeTo report clinical results and demonstrate posterior femoral translation (PFT) in medial pivot total knee arthroplasty (TKA) of posterior cruciate ligament (PCL) retaining type. Materials and methodsA prospective study was performed upon thirty consecutive subjects who were operated on with medial pivot TKA of PCL retaining type between March 2009 and March 2010 and had been followed up for at least 2 years. Clinically, the knee society knee score and function score were used. In full extension and active flexion lateral radiograph, anteroposterior (AP) condylar position and magnitude of PFT was determined. ResultsAt last follow-up, the mean knee society knee score and function score improved significantly compared to preoperative scores. The AP condylar positions were consistently posterior to midline throughout the entire range of flexion. The PFTs averaged 0.31 (±0.12) of half length of tibial base plate and were greater in higher flexion cases (r = 0.56, p = 0.0012). There were no cases having either component migration or radiolucent line wider than 2 mm except for one case showing instability related to trauma. ConclusionsIn medial pivot TKA of PCL retaining type, clinical outcomes were satisfactory and posterior femoral translations were consistently observed during progressive flexions of knees at two- to three-year follow-up.

Comparative Study of Medial Opening-Wedge High Tibial Osteotomy Using 2 Different Implants

The purpose of this study was to perform a retrospective clinical and radiographic evaluation after opening-wedge high tibial osteotomy (HTO) using a short spacer plate (Aescula; B. Braun Korea, Seoul, South Korea) and rigid long plate (TomoFix plate; Mathys, Bettlach, Switzerland) at follow-up 2 years postoperatively. We performed 94 opening-wedge HTOs with the Aescula plate (group I) and 92 HTOs with the TomoFix plate (group II). Patients underwent clinical and radiographic evaluations preoperatively and at 2 years postoperatively. Clinical evaluations were performed with Knee Society scores. Radiographic analysis included the mechanical tibiofemoral angle (mTFA) and the slope of the tibia angle with preoperative and postoperative full weight-bearing anteroposterior whole-leg views, as well as anteroposterior, lateral, and Merchant views of the knee. We measured the mTFA. In addition, we evaluated the complications in each group. The follow-up period was 2 years. At follow-up 2 years postoperatively, we observed an overall complication rate of 38% in group I and 26% in group II (P = .083). We found plate-related complication rates of 20% in group I and 9% in group II (P = .039). Plate-related complications included loss of correction, fracture of the tibial plateau, screw failure, malunion, and fracture of the lateral cortical bone. The mean mTFA was -6.0° ± 3.2° in group I and -4.6° ± 2.8° in group II preoperatively (P = .262). The mean mTFA was 1.0° ± 3.1° in group I and 1.5° ± 2.3° in group II at the latest follow-up (P = .034). In group I, the mean Knee Society knee score and function score were 60.0 ± 12.9 and 57.9 ± 26.8, respectively, preoperatively. They improved to 92.1 ± 8.1 and 89.0 ± 15.1, respectively, at follow-up (P = .001 and P = .001, respectively). In group II, the mean Knee Society knee score and function score were 57.5 ± 14.8 and 57.4 ± 22.1, respectively, preoperatively. They improved to 95.5 ± 5.4 and 95.0 ± 7.6, respectively, at follow-up (P = .001 and P = .001, respectively). In addition, the mean postoperative knee score and function score in group II were higher than those in group I (P = .001 and P = .001, respectively). We have shown a high plate-related complication rate and a significant loss of correction during a short-term follow-up period (2 years) after opening-wedge HTO using the new short spacer HTO plate compared with the rigid long plate. Level IV, therapeutic case series.

The Effects of Obesity and Morbid Obesity on Outcomes in TKA

The negative effects of obesity following total joint arthroplasty, such as increased morbidity and mortality, have been well documented in literature. However, little is known about whether specific body mass indices can be used as cutoffs to determine which patients are most at risk for having a poor postoperative outcome. We evaluated the effects of differing levels of obesity as measured by body mass index (BMI) on implant survivorship, Knee Society scores, complications, and radiographic outcomes. A systematic review of the literature was performed to identify all studies reporting outcomes of total knee arthroplasty in obese (30 ≤ BMI < 40 kg/m2) and morbidly obese patients (40 ≤ BMI < 50 kg/m2). Twenty-four studies were identified in our literature search. At a mean 5-year follow-up, morbidly obese patients (88%) had significantly lower implant survivorship than obese patients (95%) and nonobese patients (97%). Significantly, lower postoperative mean Knee Society objective and function scores (71 and 60 points) were observed for morbidly obese patients than for nonobese patients (75 and 90 points), but obese patients did not have significantly lower Knee Society objective and function scores than nonobese patients (78 and 84 points). Complication rates for nonobese, obese, and morbidly obese patients were 9, 15, and 22%, respectively, all of which were significantly different. However, no significant difference was observed in the incidence of radiolucent lines that were 12, 19, and 14%, respectively. Thus, we conclude that a BMI greater than 40 kg/m2 may be used as a cutoff to help guide patient education and treatment options for primary total knee arthroplasty.

Outcomes of Primary Total Knee Arthroplasty in the Morbidly Obese Patients

The purpose of this study was to assess the clinical and radiographic outcomes of primary total knee arthroplasty (TKA) in morbidly obese patients compared to a cohort who had a normal body mass index (BMI). We reviewed 105 knees in 84 patients who had a minimum BMI of 40 kg/m2 who underwent a primary TKA between 2006 and 2010. There were 17 men and 67 women who had a mean age of 59 years and a mean follow-up of 52 months. Outcomes evaluated included implant survivorship, Knee Society scores, activity scores, and complications. Kaplan-Meier analysis demonstrated statistically similar overall implant survivorship between the morbidly obese and the comparison groups (96 vs 97%). However, the mean Knee Society objective (85 vs 91 points) and functional scores (84 vs 89 points), as well as activity scores (4.2 vs 6.1 points) were lower and complications were higher in morbidly obese patients at final follow-up. It is encouraging that in the morbidly obese patients, total knee arthroplasty can have acceptable results at midterm follow-up, however, these patients may benefit from preoperative counseling to have realistic expectations from their surgery.

Excellent Early Outcomes of the First 100 Cruciate-Retaining TriathlonTM Total Knee Arthroplasties

Total knee arthroplasties typically have excellent survivorship (>95%) at 10 to 20 years. Implant manufacturers are attempting to address patient dissatisfaction with prostheses that recreate natural knee kinematics, which could lead to improved functional scores while still providing stability and durability. The purpose of this study was to review the outcomes of the first 100 consecutive patients who underwent a cruciate-retaining TKA. The first 100 consecutive primary total knee arthroplasties using the TriathlonTM total knee system performed by one surgeon between 2005 and 2007 were identified: 56 women and 32 men, mean age of 59 years (range, 31-83 years). Patients were followed for a mean of 36 months (range, 24-61 months). Subsequent procedures and complications were reviewed. The survival rate in the study cohort was 98% (96 of 98 knees). The mean Knee Society objective and functional scores for this cohort was 89 (range, 56-100 points) and 86 (range, 45-100 points) points, respectively, having improved from 59 (range, 34-67 points) and 55 (range, 10-80 points) points preoperatively. All failures occurred within the first 40 cases performed with the new total knee system. The next 60 cases had 100% survivorship. Excellent clinical outcomes and functional scores were found in patients who underwent a new cruciate-retaining TKA. Functional scores reported at a minimum of 2 years follow-up were comparable and often superior to published results of previous cruciate-retaining knee designs.

Do Fresh Osteochondral Allografts Successfully Treat Femoral Condyle Lesions?

Fresh osteochondral allograft transplantation is an increasingly common treatment option for chondral and osteochondral lesions in the knee, but the long-term outcome is unknown. We determined (1) pain and function, (2) frequency and types of reoperations, (3) survivorship at a median of 13.5 years, and (4) predictors of osteochondral allograft failure in the distal femur. We evaluated 122 patients (129 knees) who underwent osteochondral allograft transplantation of the femoral condyle. Mean age was 33 years and 53% were male. Clinical evaluation included the modified Merle d'Aubigné-Postel (18-point), IKDC, and Knee Society function (KS-F) scores. We defined graft failure as revision osteochondral allografting or conversion to arthroplasty. We determined whether patient characteristics or attributes of the graft influenced failure. Minimum followup was 2.4 years (median, 13.5 years); 91% had more than 10 years of followup. Mean modified Merle d'Aubigné-Postel score improved from 12.1 to 16, mean IKDC pain score from 7.0 to 3.8, mean IKDC function score from 3.4 to 7.2, and mean KS-F score from 65.6 to 82.5. Sixty-one knees (47%) underwent reoperations. Thirty-one knees (24%) failed at a mean of 7.2 years. Survivorship was 82% at 10 years, 74% at 15 years, and 66% at 20 years. Age of more than 30 years at time of surgery and having two or more previous surgeries for the operated knee were associated with allograft failure. Followup of femoral condyle osteochondral allografting demonstrated durable improvement in pain and function, with graft survivorship of 82% at 10 years.

Total Knee Arthroplasty for Rheumatoid Arthritis Patients with Large Tibial Condyle Defects

To review clinical results of total knee arthroplasty (TKA) in rheumatoid arthritis (RA) patients with large bone defects of the tibial condyle. Records of 33 knees in 27 women and 3 men aged 44 to 80 (mean, 63.6) years who underwent primary TKA for RA with large tibial bone defects were reviewed. 16 knees had peripheral defects extending to the bone cortex, whereas 17 knees had central defects that did not extend to the bone cortex. The femorotibial angle (FTA) was <170º in 15 knees, 170º to 180º in 3 knees, and >180º in 15 knees. The mean duration of RA was 13.5 (range, 3-35) years. In 14 knees with severe bone defects, bone grafts (harvested from articular surfaces of knee bones and fixed without screws or Kirschner wires) and/ or metal wedges (for peripheral defects) were used to fill the defects. Clinical outcome was assessed pre- and post-operatively using Knee Society scores. The mean follow-up duration was 6.3 (range, 2.3-13.2) years. The mean depth of tibial bone defects was 11.2 (range, 1-25) mm, whereas the mean width ratio of the bone defects was 36.5% (range, 16.4-76.9%). Mean extension and flexion (range of motion) improved from -12.5º and 113.4º to -5.1º and 115.6º, respectively. The mean Knee Society knee score improved from 35 (range, 21-59) to 85 (range, 49-95), whereas the mean Knee Society function score improved from 30 (range, 25-53) to 80 (range, 44-97) [p<0.001, Wilcoxon signed rank test]. The cruciate retention prosthesis was used in 6 knees; the posterior stabilised prosthesis was used in 27 knees; and the constrained condylar knee prosthesis was used in 3 knees. No patient had any infection or implant loosening. TKA achieved favourable outcome for RA patients with large tibial bone defects. The type of prosthesis used and the use of bone grafts and/ or metal wedges were based on the depth and width ratio of the bone defects.

Oxford phase 3 unicompartmental knee replacement in Korean patients

Medium-term survivorship of the Oxford phase 3 unicompartmental knee replacement (UKR) has not yet been established in an Asian population. We prospectively evaluated the outcome of 400 phase 3 Oxford UKRs in 320 Korean patients with a mean age at the time of operation of 69 years (48 to 82). The mean follow-up was 5.2 years (1 to 10). Clinical and radiological assessment was carried out pre- and post-operatively. At five years, the mean Knee Society knee and functional scores had increased significantly from 56.2 (30 to 91) pre-operatively to 87.2 (59 to 98) (p = 0.034) and from 59.2 (30 to 93) to 88.3 (50 to 100) (p = 0.021), respectively. The Oxford knee score increased from a mean of 25.8 (12 to 39) pre-operatively to 39.8 (25 to 58) at five years (p = 0.038). The ten-year survival rate was 94% (95% confidence interval 90.1 to 98.0). A total of 14 UKRs (3.5%) required revision. The most common reason for revision was dislocation of the bearing in 12 (3%). Conversion to a total knee replacement was required in two patients who developed osteoarthritis of the lateral compartment. This is the largest published series of UKR in Korean patients. It shows that the mid-term results after a minimally invasive Oxford phase 3 UKR can yield satisfactory clinical and functional results in this group of patients.

Results of Primary Total Knee Arthroplasty in Jehovah's Witness Patients

Total knee arthroplasty can be challenging in Jehovah's Witnesses, as these patients do not accept blood transfusions. We reported our experiences with a special blood management protocol for these patients who underwent total knee arthroplasty. There were 124 self-reported Jehovah's Witnesses who had a mean age of 64 years and who underwent total knee arthroplasties between 1998 and 2009. Mean follow-up was 60 months (range, 24-120 months). Implant survivorship, with revision for aseptic component failure as an end point, was 98%. At the final follow-up, mean Knee Society objective and function score improved to 91and 81 points, respectively. The authors believe that this blood management protocol was responsible for performing safe and transfusion-free total knee arthroplasties that can ultimately lead to excellent outcomes.

Reconstruction of the patellar tendon using a Y-shaped flap folded back from the vastus lateralis fascia

BackgroundNeglected and repeated ruptures of the patellar tendon are fortunately an uncommon event. These ruptures are often difficult to repair because they are generally accompanied by contractures of the quadriceps muscle and extensive scar tissue formation, and clinical findings are similar regardless of whether the rupture occurred during or after total knee arthroplasty. In both cases, reconstruction is the treatment. MethodsHere, we present data on reconstruction of the patellar tendon using our own method, which is performed in the following manner: the fascia flap shafted in the distal direction is separated from the vastus lateralis fascia of the quadriceps muscle, then folded back and fixed to the tibial tuberosity enclosing the patella in a Y shape. We used this new method in sixteen cases. All of the patients were examined clinically for an average of twenty-eight months. The Knee Society score was determined prior to surgery and on follow up. ResultsBoth the physical and ultrasound monitoring showed that all sixteen tendons healed properly, indicating that there was no need for any further surgical interventions. The mean Knee Society pain and function scores as well as the average range of motion of the knee increased significantly after the operations. ConclusionWe believe that the presented method is an acceptable option for functional and biomechanical repair of the patellar tendon for the following reasons: the static balance of the knee joint remains unaltered, the quadriceps muscle is not damaged, and the central pulling direction remains steady.

TKA Results Are Not Compromised By Previous Arthroscopic Procedures

This study investigated whether two or more previous arthroscopic procedures had an effect on the outcomes of total knee arthroplasty (TKA). We compared 60 patients (62 knees) who had a mean age of 56 years, a mean follow-up of 39 months (range, 26 to 68 months), and a minimum of two arthroscopic procedures before their TKA with a group of patients (n = 438) who underwent TKAs without any previous knee surgery. Clinical outcome was evaluated using Knee Society objective and function scores. Implant survivorship, with revision for aseptic component failure as an end point, was 98% in both cohorts. In the postarthroscopic group, the mean Knee Society objective and function scores improved to a mean of 92 and 89 points, respectively. Radiographic analysis did not find any differences between the two groups. In conclusion, the authors did not find that earlier arthroscopic procedures negatively affected the outcome of TKA.

Custom rotating-hinge primary total knee arthroplasty in patients with skeletal dysplasia

Patients with skeletal dysplasia are prone to developing advanced osteoarthritis of the knee requiring total knee replacement (TKR) at a younger age than the general population. TKR in this unique group of patients is a technically demanding procedure owing to the deformity, flexion contracture, generalised hypotonia and ligamentous laxity. We retrospectively reviewed the outcome of 11 TKRs performed in eight patients with skeletal dysplasia at our institution using the Stanmore Modular Individualised Lower Extremity System (SMILES) custom-made rotating-hinge TKR. There were three men and five women with mean age of 57 years (41 to 79). Patients were followed clinically and radiologically for a mean of seven years (3 to 11.5). The mean Knee Society clinical and function scores improved from 24 (14 to 36) and 20 (5 to 40) pre-operatively, respectively, to 68 (28 to 80) and 50 (22 to 74), respectively, at final follow-up. Four complications were recorded, including a patellar fracture following a fall, a tibial peri-prosthetic fracture, persistent anterior knee pain, and aseptic loosening of a femoral component requiring revision. Our results demonstrate that custom primary rotating-hinge TKR in patients with skeletal dysplasia is effective at relieving pain, with a satisfactory range of movement and improved function. It compensates for bony deformity and ligament deficiency and reduces the likelihood of corrective osteotomy. Patellofemoral joint complications are frequent and functional outcome is worse than with primary TKR in the general population.

Long-term results of total knee arthroplasty following high tibial osteotomy according to Wagner

There is relatively little information available about the long-term results of total knee arthroplasty (TKA) following high tibial osteotomy. The aim of our study was to share our experiences and long-term results of TKA after a previous closing wedge high tibial osteotomy according to Wagner. In a retrospective study we identified 48 consecutive patients who had undergone TKA after a previous closing wedge high tibial osteotomy according to Wagner with a follow-up of over ten years. The average duration of follow-up after the TKA was 13.3 years (min 10.0, max 15.5). X-rays were taken in two planes before TKA, one week after TKA and at the latest follow-up. Tibio-femoral alignment was measured on weightbearing long-leg anteroposterior radiographs. Radiolucent lines at the latest follow-up were documented. Functional evaluations were performed preoperatively and postoperatively (at the time of latest follow-up). The mean Knee Society function score increased from 63.1 points preoperatively to 90.0 points postoperatively. The mean overall Knee Society score increased from 93.2 points preoperatively to 160.8 points postoperatively. The mean average femoro-tibial angle was corrected from varus 0.8° (varus 14°-valgus 8.0°) preoperatively to valgus 7.6° (valgus 2-9°) at the last follow-up. The closing wedge high tibial osteotomy according to Wagner does not compromise subsequent total knee replacement and leads to good clinical and radiological results.

No Long-term Difference Between Fixed and Mobile Medial Unicompartmental Arthroplasty

Early studies in the literature reported relatively high early minor reintervention rate for the mobile-bearing unilateral knee arthroplasty (UKA) compared with short- and midterm survivorship after fixed- or mobile-bearing UKA. However, whether the long-term function and survivorship are similar is unclear. We therefore asked whether (1) mobile- or fixed-bearing UKAs have comparable function (as measured by the Knee Society scores); (2) mobile- and fixed-bearing UKA have comparable Knee Society radiographic scores; and (3) the long-term survivorship is comparable. We retrospectively reviewed 75 patients (79 knees) with a fixed-bearing UKA and 72 patients (77 knees) with a mobile-bearing UKA operated on between 1989 and 1992. Mean age of the patients was 63 years; gender and body mass index (26 kg/m(2)) were comparable in the two groups. We obtained Knee Society function and radiographic scores and determined survival. The minimum followup was 15 years (mean, 17.2 ± 4.8 years; range, 15-21.2 years). The mean Knee Society function and knee scores were comparable in the two groups. Radiographically, the number of overcorrections and the number of radiolucencies were statistically higher in the mobile-bearing group (69% versus 24%). At final followup, considering revision for any reason, 12 of 77 (15%) UKAs were revised (for aseptic loosening, dislocation, and arthritis progression) in the mobile-bearing group and 10 of 79 (12%) in the fixed-bearing group (for wear and arthritis progression). This long-term study did not demonstrate any difference in survivorship between fixed and mobile-bearing but pointed out specific modes of failure.

Role of Knee Flexion in the Quality of Life of Patients Implanted With Primary TKA

Achieving complete pain relief and improving mobility are the 2 main goals after total knee arthroplasty (TKA). First is to restore patient function and second is to improve patient quality of life. Mobility after TKA and particularly range of knee flexion is related to the patient, the implant, and last but not least, the surgical management. The goal of this study was to evaluate the impact of the flexion restoration on the patient's quality of life. Between September 2000 and January 2005, 516 consecutive TKAs in 445 patients operated on in the same center were prospectively followed. The same high-flexion posterostabilized mobile- bearing implant was systematically used. Mean patient's age was 71±8 years, mean body mass index was 28±4kg/m 2 . At follow-up, an objective evaluation was performed by 2 independent observers. Objectively, the postoperative range of knee flexion was 128±4 degrees and the mean Knee Society function and knee scores were respectively 91±6 and 96±3. Higher range of flexion and Knee Society knee scores were significantly correlated with better quality of life scores (P<0.001). The results of this study showed that patient quality of life was correlated with a higher range of knee flexion.

Rotaglide Total Knee Arthroplasty: A Long-Term Follow-up Study

Mobile-bearing knee designs represent an alternative to conventional fixed-bearing implants in total knee arthroplasty. The purpose of this study was to determine the clinical results of a mobile-bearing knee implant. From 1990 to 1998, 326 primary consecutive mobile-bearing total knee prostheses were implanted in 260 patients who had a mean age and standard deviation of 66.7 ± 6.9 years. Femoral and tibial components were cemented in all knees, and the patella was resurfaced in 199 knees (61%). Patients were evaluated with the use of the Knee Society clinical rating system and radiographic examinations. Complications were noted, and survivorship of the prostheses was determined. The mean follow-up period was 156 ± 27.3 months, with maximum follow-up at eighteen years. The mean Knee Society knee score improved from 32.4 ± 21.2 preoperatively to 92.6 ± 10.0 at the time of the last follow-up (p = 0.00), and the mean Knee Society functional score improved from 39.3 ± 18.7 preoperatively to 66.7 ± 18.6 at the time of the last follow-up (p = 0.00). Mean knee flexion improved from 92.3° ± 14.5° preoperatively to 112.1° ± 13.4° at the time of the last follow-up (p = 0.00). There were twenty-four (7.4%) knees that required revision. In eighteen (5.5%) knees, worn out or broken polyethylene was found and a polyethylene-only exchange was done. Six knees (1.8%) were fully revised. The survival rate was 0.96 (95% confidence interval, 0.93 to 0.98) at ten years and 0.87 (95% confidence interval, 0.79 to 0.93) at eighteen years. A fully congruent, mobile-bearing total knee prosthesis had excellent survivorship during the ten to eighteen-year follow-up interval.