Postoperative Anteroposterior Laxity Influences Subjective Outcome After Total Knee Arthroplasty

Background

We hypothesized that postoperative anteroposterior (AP) stability of the knee correlates with patient-reported clinical outcome and knee function after total knee arthroplasty (TKA).

Comparative study of stability after total knee arthroplasties between navigation system and conventional techniques

The aim of this study was to evaluate the stability of mediolateral laxity in extension and anteroposterior laxity in 90 degrees of flexion using stress radiographs, modified Hospital for Special Surgery scores, and range of motion of total knee arthroplasties (TKAs) performed using a navigation system (navigation-assisted group, 42 knees) after a minimum 1-year follow-up and to compare them with those of a conventional TKA (conventional group, 44 knees) using a gap technique. The mean medial laxities were 3.5 degrees in the navigation-assisted group and 4.0 degrees in the conventional group, and the mean lateral and anteroposterior laxities were 4.4 degrees and 4.2 degrees in 7.1 and 7.0 mm, respectively. These results showed no significant differences between the 2 groups. Thus, we concluded that there is no significant difference between navigation-based and conventional techniques in terms of TKA stability. In addition, no significant differences were found between the 2 groups in modified HSS scores or range of motion.     

The effect of sagittal laxity on function after posterior cruciate-retaining total knee replacement

We studied sagittal laxity using the KT1000 arthrometer in 97 total knee arthroplasties (TKAs) in 83 patients using the porous-coated anatomic knee or Duracon TKA (Howmedica, Rutherford, NJ) with 5.4- to 9.9-year follow-up. Two differing tibial inserts were used: flat (group 1) and anteroposterior (AP) lipped (group 2). Greater posterior and total laxity at 75 degrees was seen in group 2 despite the AP-lipped insert. No differences were seen in functional outcome scores between groups. No significant relationship was seen between laxity and functional outcome. Knees with more than 10 mm of AP laxity at 75 degrees had significantly less flexion and lower Knee Society Scores than knees with 5 to 10 mm of AP laxity. We conclude that the optimal sagittal laxity in this cruciate-retaining TKA is between 5 and 10 mm, although this may not hold for posterior-stabilized designs.     

In vivo stability of total knee arthroplasty using a navigation system

The aim of this study was to evaluate in vivo stability for mediolateral laxity in extension and anteroposterior laxity in 90° of flexion and to correlate these and the range of motion (ROM) in 42 total knee arthroplasties (TKA) performed using a navigation system, with a minimum 1-year follow-up. The following parameters were measured at the final follow-up: mediolateral laxity in extension and anteroposterior laxity in 90° of flexion as determined by stress radiographs and a Telos arthrometer, modified HSS scores (excluding laxity and range of motion) and the range of motion (ROM). The mean modified HSS score was 82% of 82 maximum allowable points, and the mean postoperative ROM was 128.1±10.4°. Mean medial laxity was 3.5±1.4°, mean lateral laxity was 4.4±2.2° and mean anteroposterior laxity was 7.1±4.1 mm. We found no significant correlation between mediolateral laxity and postoperative ROM. However, a significant correlation was found between postoperative ROM and anteroposterior laxity. In conclusion, the use of a navigation system in TKA assists the surgeon to achieve good in vivo stability. Short-term clinical results are promising.

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Résumé Le but de cette étude est d’évaluer la stabilité latérale en extension et la stabilité antéropostérieure en flexion à 90° des PTG en corrélation avec le degré de mobilité sur 42 genoux mis en place en utilisant un système de navigation, avec un minimum de suivi d’un an. La laxité médio-latérale en extension, la laxité antéropostérieure en flexion à 90° ont été évaluées en utilisant des radiographies en stress (arthromètre Télos), a également été utilisé le score HSS et l’évaluation du degré de flexion du genou au dernier recul. Le score HSS était dans plus de 82% des cas supérieur à 82 points avec une flexion moyenne du genou de 128,1±10,4°. La laxité interne de la mesure a été de 3,5±1,4°, la laxité externe de 4,4±2,2° et la laxité antéropostérieure de 7,1±4,1 mm. Nous n’avons pas trouvé de corrélation significative entre la laxité latérale et le degré de flexion du genou. Cependant nous avons retrouvé une corrélation significative entre le degré de flexion du genou et la laxité antéropostérieure alors qu’il n’y avait pas de corrélation entre laxité médio-latérale et la mobilité. En conclusion, l’utilisation d’un système de navigation dans la mise en place d’une prothèse totale du genou est une aide certaine pour obtenir une meilleure stabilité et des résultats à court terme prometteurs.

     

Varus-valgus balance and range of movement after total knee arthroplasty

We performed a randomised, prospective study of 80 mobile-bearing total knee arthroplasties (80 knees) in order to measure the effects of varus-valgus laxity and balance on the range of movement (ROM) one year after operation. Forty knees had a posterior-cruciate-ligament (PCL)-retaining prosthesis and the other 40 a PCL-sacrificing prosthesis. In the balanced group (69 knees) in which the difference between varus and valgus was less than 2 degrees, the mean ROM improved significantly from 107.6 degrees to 117.7 degrees (p < 0.0001). By contrast, in the 11 knees which were unbalanced and in which the difference between varus and valgus laxity exceeded 2 degrees, the ROM decreased from a mean of 121.0 degrees to 112.7 degrees (p = 0.0061). We conclude that coronal laxity, especially balanced laxity, is important for achieving an improved ROM in mobile-bearing total knee arthroplasty.     

Unicompartmental tibial hemiarthroplasty: early results of the UniSpacer knee

An intra-articular metallic spacer is evaluated for the treatment of isolated medial compartment OA. It is proposed that this implant can provide axial correction for a varus deformity, eliminate the pseudolaxity of the MCL, improve knee function, maintain ROM, and provide pain relief. One-and 2-year data are presented on 71 UniSpacer Knee System implants that were implanted in 67 patients (four had bilateral surgeries). The mean age and weight of these patients was 54 years and 94 kg (207 lb), respectively. The heaviest patient in the group weighed 168 kg (370 lb). All knees were evaluated using the Knee Society clinical rating system, Lysholm scoring scale, radiographic limb alignment, and ROM. The mean Knee Society knee score improved 169% in the 1-year group and 193% in the 2-year group. The mean Knee Society function score improved 31% and 65%, respectively. The mean Lysholm score improved 88% and 140%, respectively. Five implants (7%) were revised to total knee arthroplasty (TKA) and 10 implants (14%) were revised to another UniSpacer Knee System implant. The early results suggest that an intra-articular metallic spacer is a viable treatment option for OA in the younger patient.     

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.     

Antibiotic-loaded articulating cement spacers in two-stage revision for infected total knee arthroplasty: individual antibiotic treatment and early results of 21 cases

Objective:To detail our early experience and technique of a modified two-stage reimplantation protocol using antibiotic-loaded articulating cement spacers (ALACSs) for treatment of late periprosthetic ...     

Preoperative knee stiffness and total knee arthroplasty outcomes

A retrospective case-control study was conducted to evaluate 1-year total knee arthroplasty (TKA) outcomes among preoperative stiff knees, range of motion (ROM) 80° or less, compared with nonstiff preoperative knees, ROM 100° or greater. A total of 134 stiff knee cases were compared with a matched cohort of 134 non-stiff knee controls. Knee Society Score and Oxford Knee Score change scores from baseline to 1 year were similar between the groups. Stiff knees experienced a significantly greater mean improvement in ROM from baseline to 1 year (30.8° ± 18.8°) as compared with nonstiff knees (1.1° ± 12.8°) (P < .0001). Although ultimate ROM of a TKA can be restricted secondary to preoperative stiffness, improvements in outcomes and ROM are not affected. We conclude that progression of stiffness should not in and of itself lead to earlier intervention of TKA in most cases.     

增加胫骨平台后倾角度、后交叉韧带部分松解对全膝关节置换术后膝关节运动影响的实验研究

目的通过增加胫骨平台后倾角度或后交叉韧带（PCL）部分松解对全膝关节置换术（TKA）中屈曲间隙过紧进行处理,分析这两种方法对TKA术后膝关节运动学的影响。方法测量6例新鲜尸体膝关节标本在完整状态下、正常TKA、屈曲间隙过紧、增加胫骨平台后倾角以及PCL部分松解TKA术后膝关节屈曲0°、30°、60°、90°、120°时的前后松弛度、内外翻松弛度、旋转松弛度及最大屈曲度。结果屈曲过紧TKA与正常TKA相比,在屈曲30°、60°、90°和120°时前后松弛度、内外翻松弛度及旋转松弛度均显著较小（P〈0．05）。与屈曲过紧TKA相比,增加胫骨后倾角后,在屈曲30°、60°、90°和120°时前后松弛度、内外翻松弛度和旋转松弛度均明显增大（P〈0．05）。PCL部分松解与屈曲过紧TKA相比,在屈曲30°、60°、90°和120°时前后松弛度明显增加（P〈0．05）;旋转松弛度在屈曲30°、60°、90°时明显增加（P〈0．05）。与PCL部分松解相比,增加胫骨后倾角的内外翻松弛度在屈曲30°、60°、90°时明显较大（P〈0．05）;旋转松弛度在屈曲0°、30°、60°和90°时明显较大（P〈0．05）。屈曲过紧TKA的最大屈曲度（120．4°）与正常TKA（130．3°）及增加胫骨后倾角（131．1°）相比明显较小（P〈0．05）。增加后倾角与PCL部分松解（124．0°）相比,最大屈曲度较大,但差异无统计学意义（P=0．0816）。结论屈曲间隙过紧TKA术后膝关节的前后松弛度、内外翻松弛度、旋转松弛度和最大屈曲度均减小;增加胫骨平台后倾角后,前后松弛度、内外翻松弛度、旋转松弛度和最大屈曲度均明显增大;PCL部分松解仅能明显增大前后松弛度。因此对于TKA术中屈曲紧张的膝关节,增加胫骨平台后倾角比PCL部分松解能更好地改善膝关节的运动学。     

Ten-year survival and clinical results of constrained components in primary total knee arthroplasty

The use of constrained prostheses in primary total knee arthroplasty (TKA) is unusual. This is a study of the indications, clinical results, and 10-year survival of these components. Fifty-four knees (44 patients) were prospectively followed, and 42 knees (34 patients) had 5 to 16 years (mean, 9 years) of follow-up. The indications for the components were valgus deformity with incompetent medial collateral ligament in 27 knees, severe flexion contracture with inability to balance the knee in 12, and others in 3. Knees were evaluated by the Hospital for Special Surgery and Knee Society score systems. Statistical analysis included paired Student t test and survivorship analysis. Of the entire cohort of 54 knees, there were only 2 failures: a tibial loosening revised at 3 years and a femoral loosening (no stem) revised at 1 year. Of the 42 knees with minimum 5-year follow-up, 12 knees were rated as excellent, 24 good, 3 as fair, and 3 as poor. There was a significant improvement in postoperative knee score, but not in the function score. The mean flexion contracture preoperatively was 17 degrees; postoperatively, 1.7 degrees; and mean flexion preoperatively, 93 degrees; postoperatively, 97 degrees. The 10-year survival with failure, defined as component revision for loosening, was 96% (confidence interval, 90.6%-100%). In difficult primary TKAs, there were 86% good or excellent results and a 10-year survival of 96% despite the increased constraint. The constrained condylar TKA remains indicated for knees with severe valgus deformity, incompetent medial collateral ligament, or severe flexion contracture in which the knee cannot be properly balanced.     

The "banana peel" exposure method in revision total knee arthroplasty

We present an exposure technique, the "banana peel," that has been used exclusively for revision total knee arthroplasty (TKA) for more than 20 years. We retrospectively reviewed use of this technique in 102 consecutive patients (mean age, 62 years; range, 41-92 years) who underwent tibial-femoral stemmed revision TKA. There were 5 deaths, leaving 97 patients (98 knees) for the study. The technique involves peeling the patella tendon as a sleeve off the tibia, leaving the extensor mechanism intact with a lateral hinge of soft tissue. A quadriceps "snip" is also done proximally. Patients with a minimum follow-up of 24 months were included. Telephone interviews and chart reviews were conducted, and Knee Society scores were obtained. Mean follow-up was 39 months (range, 24-56 months). No patient reported disruption of the extensor mechanism or decreased ability to extend the operative knee. Mean Knee Society score was 176 (range, 95-200). Mean postoperative motion was 106 degrees. No patient reported pain over the tibial tubercle. The banana-peel technique for exposing the knee during revision TKA is a safe method that can be used along with a proximal quadriceps snip and does not violate the extensor mechanism, maintaining continuity of the knee extensors.     

Knee stability in posterior cruciate ligament retaining total knee arthroplasty

Anteroposterior knee laxity was evaluated in 14 patients (19 knees) who had posterior cruciate ligament retaining total knee arthroplasty using the Miller Galante I prosthesis. The followup ranged from 87 to 118 months (average, 105.9 months), and the measurements were done using the KT-2000 arthrometer. The mean anteroposterior displacement with the knees with Miller Galante I prostheses was 10.1 mm at 30 degrees flexion and 8.1 mm at 75 degrees flexion. In the 15 knees with Miller Galante I prostheses with flexion greater than 90 degrees, seven had less stability at 75 degrees than at 30 degrees flexion. These knees were considered to have a nonfunctional posterior cruciate ligament, and they had a worse Knee Society score (81.1) than did the other eight knees with Miller Galante I prostheses (89.9). There were four knees in which the flexion was less than 90 degrees. In this study, approximately half of the knees with posterior cruciate ligament retaining total knee arthroplasty did not have good anteroposterior stability in flexion an average of 9 years after surgery.     

Partial Lateral Patellar Facetectomy as an Alternative to Lateral Release in Total Knee Arthroplasty (TKA)

This study presents the selective use of partial patellar lateral facetectomy for maltracking during primary TKA, as an alternative to lateral release. Twenty three partial facetectomies were performed out of 191 TKAs (12%). Balanced tracking was achieved in 22 knees. At follow-up 2 patients had persistent anterior knee pain. Mean Knee Society score (KSS) was 94 and mean functional KSS was 86. Mean patellar score was 28. Patellar tilt angles were within 2 degrees in all but one knee. Patellar translation was within 2 mm in all cases. No complications were recorded. A control group of 46 matched patients had similar functional and radiographic results. If tracking is not satisfactory at the conclusion of TKA, our method of choice would be partial lateral facetectomy.     

Midterm outcome of the Duracon total knee arthroplasty

PURPOSE. To present midterm results of Duracon total knee arthroplasty (TKA) performed between 1991 and 2001. METHODS. One man and 43 women (65 knees) aged 46 to 84 (mean, 63) years who underwent primary TKAs using the Duracon prosthesis performed by a single surgeon were followed up for a mean of 8.5 (range, 5-11) years. All TKAs were cruciate-retaining and cemented, with only 9 of the patellae resurfaced. The diagnosis was osteoarthritis in 42 patients (61 knees), and rheumatoid arthritis in 2 patients (4 knees). Patients were assessed using the Knee Society Clinical Rating System, the Oxford Knee Score, and the Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. RESULTS. The mean Knee Society knee score was 86 (range, 43-100) and the function score was 68 (0- 100). 94% of patients reported no or only mild pain. The mean Oxford Knee Score was 19. There was no patellofemoral complication, deep vein thrombosis or pulmonary embolism. Complications included a superficial infection and an uncontrolled deep infection. One patient had the insert exchanged for wear at the 11-year follow-up, and another had the polyethylene insert and tibial tray revised after a motorcycle accident. CONCLUSION. The Duracon TKA had good midterm clinical results with absence of patellofemoral complications.     

A recession of posterior cruciate ligament in posterior cruciate-retaining total knee arthrosplasty

The range of motion, the stability of the knee, and the prevalence of radiolucent lines in 68 posterior cruciate-retaining (CR) total knee arthroplasties (TKAs) with a retained, but balanced, posterior cruciate ligament were compared with those in 68 knees with a posterior cruciate-substituting (PS) TKAs in the 60 patients who were managed with simultaneous bilateral TKAs. The average range of motion in both groups (126 degrees vs 129 degrees) at the latest follow-up was not significantly different (P = .359). No significant difference in the sagittal laxity of the knee was seen between 2 groups. The prevalence of radiolucent lines was 7% in the CR TKA with a recession posterior cruciate ligament and 12% in the PS TKA group (P = .108). We feel that posterior stabilization is unnecessary in the PS flex knees.     

Range of motion of standard and high-flexion cruciate retaining total knee prostheses

Recently, use of high-flexion design was introduced in cruciate-retaining (CR) total knee prostheses. The purpose of this study was to prospectively compare the ranges of motion (ROMs) of 89 knees with standard and 87 knees with high-flexion CR total knee prostheses. Differences in age, gender, diagnosis, preoperative ROM of the knee, and Knee Society Score between the 2 groups were not statistically significant. At 12-month follow-up, average ROM was 112.0 degrees +/- 12.6 degrees for standard, and 115.3 degrees +/- 13.4 degrees for high-flexion CR prosthesis (P = .101). To our knowledge, this is the first report on the ROM with the high-flexion CR total knee prosthesis. Using the technique of anterior referencing for femoral component sizing and using a fixed 7 degrees slope for the tibial component, we found no significant differences between groups with regard to ROM, clinical, or radiographic parameters.     

Primary total knee arthroplasty in patients with fibromyalgia

No data on the results of total knee arthroplasty (TKA) in patients with fibromyalgia have been published. The purposes of this study were to review a cohort of patients with fibromyalgia undergoing TKA to determine the level of postoperative pain and satisfaction with the surgery, the incidence of postoperative surgical complications, and revision rates and their relationship to TKA design. One hundred ten patients with fibromyalgia (141 knees) who underwent primary TKA between 1990 and 2001 were studied. The average age was 64 years (range, 39-86 years), and the average follow-up was 7 years (range, 2-16 years). Forty-five knees were cruciate retaining, and 96 had a posterior stabilized design. Clinical outcome was assessed using the Knee Society Knee Score and satisfaction regarding the results of the procedure. Postoperative surgical complications and reoperations were obtained from the registry. Sixty-two patients (44%) continued with some pain after TKA. Eighty-five patients (82%) were satisfied with the results. The most common complications were arthrofibrosis and symptomatic instability. The revision rate was 6% (8 knees). Survivorship free from revision at 7 years was 89% for cruciate retaining knees and 98% for posterior stabilized knees. Patients with fibromyalgia undergoing primary TKA have a high prevalence of complications and pain. Despite continued pain, the majority of patients were satisfied with the results and reported improvements after TKA. This data should be used to counsel patients with fibromyalgia preoperatively regarding limited goals with respect to pain relief and suggests that a multimodal individualized treatment program may be necessary to achieve optimal outcomes in patients with fibromyalgia.