Patellofemoral complications after posterior-stabilized total knee arthroplasty: a comparison of 2 different implant designs

We conducted a retrospective review of 2 consecutive series of posterior-stabilized total knee arthroplasties (TKAs) to evaluate patellofemoral complications, in particular, significant patellofemoral crepitance or patellar clunk syndrome. Twenty posterior-stabilized Axiom PSK (Wright Medical Technology, Arlington, TN) TKAs (group 1) were compared with 20 posterior cruciate-sacrificed Advance medial pivot (Wright Medical Technology, Arlington, TN) TKAs (group 2). The average age in group 1 was 69 years and in group 2 was 70 years. Preoperative valgus alignment in group 1 was 7.5 degrees and in group 2 was 1.3 degrees. Postoperative valgus alignment for the 2 groups was 4.8 degrees and 5.3 degrees valgus. Postoperative patellar tilt for the 2 groups was 0.9 degrees lateral tilt and 8 degrees lateral tilt. Patellofemoral signs of crepitance > or =2+ and significant box impingement complaints of either snapping or clunking decreased significantly postoperatively from 5 of 20 (25%) in group 1 to 0 of 20 in group 2 (P=.0079).     

Patellofemoral complications in symmetrical total knee arthroplasty

A review of 356 Kinemax (Howmedica, Inc, Rutherford, NJ) cemented posterior cruciate ligament-retaining condylar total knee arthroplasties employing a symmetrical femoral component articulating with a medially offset symmetrical dome patella component was carried out to examine the results and determine the incidence and nature of the patellofemoral complications. Follow-up was from 3 to 8 years, with a mean of 5.1 years. A review of patellofemoral complications in previously reported homogeneous series of symmetrical and asymmetrical implants is presented. Mean postoperative Knee Society scores improved to 91, function scores to 86, and Hospital of Special Surgery scores to 90 yielding 95% good and excellent results. Mean postoperative range of motion was −1.5° extension to 113° flexion. There were five patellofemoral complications (1.4%), including two symptomatic subluxations, two distal pole avulsion fractures, and one lateral facet fracture. There were two reoperations necessary for patellofemoral problems (0.56%), one to correct subluxation and one for excision of the fractured lateral facet. These rates are lower than those previously reported for asymmetrical implants as well as current and phased-out symmetrical designs of total knee arthroplasty in the intermediate term. This review suggests that cemented total knee arthroplasty with symmetrical patellofemoral resurfacing with an offset patella dome and posterior cruciate ligament retention yields low patellofemoral complications and reoperations. The symmetrical femoral component appears to be a satisfactory compromise of “normal” femoral anatomy, which decreases inventory and cost without adversely affecting patellofemoral function and complications.     

Dislocation of Insall-Burstein II modified total knee arthroplasty

Dislocation of total knee arthroplasty is a rare but serious complication. The experience with the Insall-Burstein II modified knee prosthesis, which was designed to address the issue of dislocation, has been favorable. We present a series of 3 dislocations in 1,500 total knee arthroplasties done with this prosthesis, accounting for about 0.2% of cases.     

Patellofemoral function after total knee arthroplasty: a comparison of 2 posterior-stabilized designs

Knee complications and function were analyzed in patients with 2 different posterior-stabilized total knee arthroplasty (TKA) designs, Optetrak 913 and Insall-Burstein II. Three hundred Insall-Burstein II knees with mean follow-up of 8 years (range: 5-9 years) and 300 Optetrak knees with mean follow-up of 6 years (range: 5-7 years) were studied. Lateral retinacular release was performed in 30% of Insall-Burstein II patients and 16% of Optetrak patients (P = 0.001), and patellar clunk was 4% for the Insall-Burstein II prosthesis and 0.3% for the Optetrak prosthesis (P = 0.003). No statistically significant differences in dislocation, fracture, or loosening rates were observed between the 2 groups. Knee Society scores were similar in 2 groups of 50 patients brought back to the office. Mean Knee Society knee scores were 92 and 94 for the Insall-Burstein II and Optetrak groups, respectively (P > 0.05), and function scores were 80 and 84 for the 2 groups, respectively (P > 0.05). At mid-term follow-up, Optetrak patients were less likely than Insall-Burstein II patients to require lateral retinacular release and experience patellar clunk.     

Comparison of the Insall-Burstein II and NexGen legacy total knee arthroplasty systems with respect to patella complications

This study retrospectively contrasts 2 cohorts of consecutive patients "(N = 202) after primary total knee arthroplasty with respect to the types and numbers of patella and extensor mechanism complications. Our results demonstrated an overall decrease of patellofemoral complications associated with the NexGen Legacy PS system (Zimmer Inc, Warsaw, Ind). Patella fractures decreased from 6 to 0 (P = .013), avascular necrosis from 9 to 0 (P = .0002), and lateral retinacular release trended down from 24 to 14. The Insall-Burstein II (Zimmer Inc, Warsaw, Ind) has a significantly higher incidence of patella fractures, avascular necrosis, and the lateral retinacular release. We feel that the alteration and adjustment of the patellofemoral dimension in the NexGen Legacy design to a more anatomical, extended design of the femoral component and patella modifications led to a decrease in the incidence of complications.     

Insall-Burstein posterior-stabilized knee prosthesis in rheumatoid arthritis

The authors reviewed 65 Insall-Burstein (Zimmer, Warsaw, IN) total condylar posterior-stabilized knee prostheses in 50 patients with rheumatoid arthritis with a follow-up period of at least 5 years (range, 5–13 years). Forty-two knees in 31 patients were evaluated using the Knee Society knee and functional rating scores. Radiographic assessment was performed using standing long radiographs (hip to ankle). Radiolucent lines were studied using fluoroscopic-centered views. Excellent or good clinical results were obtained in 95% of the cases, and the average knee score improved from 22.5 to 90 points. No cases of radiologic loosening were observed. Incomplete radiolucent lines around the tibial component were detected in only 17% and were nonprogressive. Two patients developed hematogenous late deep infection, which required removal of the prosthesis in both, followed, at a second stage, by arthrodesis in one and prosthesis reimplantation in the other. Three knees (7%) had a painful impingement of the patella. Two of these were successfully reoperated with arthroscopic debridement of the peripatellar synovial tissues. Survivorship analysis, based on endpoints such as prosthesis removal for any cause or radiologic loosening (complete radiolucent line thicker than 1 mm, tilt, or subsidence of the component), showed a cumulative success rate of 96.2% at 13 years.     

Dislocation following primary posterior-stabilized total knee arthroplasty

From 1981 through 1991, 3, 032 primary total knee arthroplasties were performed using the Insall-Burstein Posterior Stabilized Condylar Prosthesis (IB-I, IB-II, and IB-II modified) (Zimmer, Warsaw, IN). Fifteen posterior dislocations occurred: 4 with the IB-I system occurring 2 or more years after surgery, 10 with the IB-II system (8 occurring 6 months after surgery and 2 occurring 2–3 years after surgery), and 1 with the IB-II modified system occurring 9 months after surgery. Statistically significant differences for the rate of dislocation between both the IB-I and IB-II modified arthroplasties versus the IB-II arthroplasties were found (P < .001). In an attempt to identify a cause for these dislocations, the authors retrospectively assessed the 15 dislocated cases with respect to sex, age, weight, height, preoperative and postoperative Hospital for Special Surgery scores, preoperative and postoperative alignment, preoperative versus postoperative reconstruction dimensions, patellar thickness and height, and postoperative flexion and compared the results with those patients who did not experience dislocation. Possible etiologies and mechanisms of dislocation were sought. There were no significant differences between the control and study groups for any variable assessed, with the exception of postoperative flexion, which averaged 118° for the study group and 105° for the control group (P < .001). Conservative management was successful in 11 cases. In September 1988 the IB-II system was introduced; modification of the tibial insert was made in January 1990. The 10 IB-II dislocations occurred prior to the modification of the modular tibial polyethylene insert, and the 3 recurrent dislocations in this group were successfully treated with revision to this modified insert. Since this modification, 656 IB-II modified systems have been implanted with one dislocation (0.15%).     

Patellofemoral resurfacing at total knee arthroplasty

A retrospective review of 268 primary total knee arthroplasties (TKAs) with a mean follow-up of four years is presented. The patellae were resurfaced in all cases. There were six complications (2.2%) referable to the patellofemoral articulation: three subluxations, one patellar fracture, one loosening of a metal-backed patellar component, and one patellar tendon avulsion. Successful patellofemoral resurfacing (PFR) can be accomplished with minimal complications if the following technical considerations are met: 5-7 degrees of valgus alignment; medial placement of the patellar component; taking care not to increase either the AP diameter of the knee or the thickness of the patella; avoiding internal rotation of either the tibial or femoral components and proper soft tissue balancing. A thorough review of patellofemoral complications after TKA is presented, and technical considerations relevant to the successful performance of PFR are discussed.     

Tibial post impingement in posterior-stabilized total knee arthroplasty

Reports of posterior-stabilized total knee replacements have shown excellent clinical success. However, tibial post-femoral cam impingement has been seen in modular component retrievals. This finding has been associated with transmission of rotational forces to the modular tray-polyethylene interface with subsequent backside polyethylene wear and the development of osteolysis. Femoral cam-tibial post designs that allow hyperextension and limit rotational constraint may minimize this impingement. Technical considerations including the avoidance of femoral component flexion and posterior tibial slope will minimize anterior tibial post impingement.     

Posteriorly stabilised (Insall-Burstein) total condylar knee arthroplasty

Summary We reviewed 157 knees in 118 patients who underwent posteriorly stabilised (Insall-Burstein) knee replacement arthroplasty. Their mean age at operation was 69 years (range 47 to 85 years) and the average follow-up was 3.5 years (range 2 to 7 years). The BASK knee function assessment chart was utilised to evaluate the functional and clinical results. One hundred and thirty-five knees (86%) had excellent or good results, 16 knees (10%) had fair results and six (4%) had poor results. The mean postoperative BASK score was 79 points and the average postoperative knee flexion was 95° (range 65° to 130°). Two patients had a superficial infection, one deep sepsis requiring revision arthroplasty and two mechanical loosening. Patellar impingement symptoms were present in 8% of the knees, although they were troublesome in less than half. Varus alignment of the knee and a varus tilt of the tibial component of more than 2° correlated with the incidence of radiolucent lines around the tibial prosthesis. 90% of the patients were pleased or satisfied with the functional result. The total condylar knee is a safe, reliable and versatile prosthesis.

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Résumé Nous avons revu 157 genoux chez 118 malades ayant bénéficié d'une arthroplastie par prothèse semi-contrainte (Insall-Burstein). L'âge moyen lors de l'opération était de 69 ans (de 47 à 85) et le recul moyen était de 3 ans et demi (de 2 à 7). Pour évaluer les résultats fonctionnels et cliniques, nous avons eu recours à l'échelle de cotation fonctionnelle «BASK». Le résultat était excellent ou bon dans 135 genoux (86%), moyen dans 16 (10%) et mauvais dans 6 (4%). La cotation post-opératoire «BASK» était en moyenne de 79 points et la flexion post-opératoire moyenne de 95° (de 65° à 130°). Deux opérés avaient présenté une infection superficielle, un seul un sepsis profond ayant nécessité une reprise de l'arthroplastie et deux un descellement mécanique. Des signes d'hyperpression rotulienne pouvaient être notés dans 8% des genoux mais ils n'avaient de traduction clinique que dans moins de la moitié des cas. L'existence d'un liseré autour de la pièce tibiale êtait correlée avec une désaxation du genou en varus ou avec un positionnement en varus du composant tibial supérieur à 2°. La prothèse total-condylar est donc sûre, efficace et susceptible de s'adapter aux diverses éventualités.

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Reprint requests to: P. M. Aichroth     

国产TC-Dynamic(后稳定型)膝关节假体置换的临床应用

目的：膝关节置换在国内已广泛开展,发展合适国人自身的假体意义重大,本研究介绍了国产TC-Dy—namic（后稳定型）膝关节置换系统在临床的应用体会。方法：自2003年1月至2004年12月,对51例患者行TC-Dy—namic膝关节置换。男19例,女32例;年龄71—84岁,平均（76．4±4．1）岁;骨性关节炎37例,类风湿性关节炎14例;病程5～40年,症状主要为疼痛及活动受限。术前术后行HSS评分和X线检查。结果：随访48-61个月,术后3个月随访所有患者,HSS评分平均（86．1±7．7）分（63～95分）;共32例患者获48个月随访,HSS评分平均（83．5±8．1）分（60±95分）。负重位X线检查力线测量结果：术前平均膝内翻（21．0±5．8）°（9°±30°）,术后下肢力线基本正常。无感染、假体松动或髌骨脱位等并发症。结论：作为根据国人膝关节解剖特点设计的后稳定型膝关节假体置换术中期疗效满意,长期疗效有待观察。     

Patellofemoral function in total condylar knee arthroplasty

Summary A series of 100 total condylar knee arthroplasties was studied to determine radiographic and clinical patellofemoral function. Before operation there was lateral patellar tilt in 31 cases and lateral displacement in 52. After operation tilt was present in 8 and displacement in 14. Only a few patients had medial patellar displacement. Dislocation or fracture of the patella was not encountered. Six patients had postoperative patellar pain. In one case there was a radiolucent zone at the bone-cement interface in the patella, without pain. Patellofemoral function before operation was good in 3, fair in 54, and poor in 43 cases. After operation it was good in 88 and fair in 12. Both tilt and displacement slightly reduced postoperative patellofemoral function. Patellar reconstruction with the total condylar prothesis shows reasonably good tolerance of moderate malpositioning of the patellar prosthesis, affords sufficient stability and usually painless patellofemoral function.

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Résumé Les auteurs ont étudié une série de 100 arthroplasties du genou de type »total condylar« afin d'apprécier cliniquement et radiologiquement la fonction fémoro-patellaire. Avant l'opération il existait une bascule externe de la rotule dans 31 cas et une subluxation externe dans 52. Après l'opération, la bascule a été retrouvée 8 fois et la subluxation 14 fois. Quelques malades seulement présentaient une subluxation interne. Il n'y avait ni luxation ni fracture de la rotule. Six opérés se plaignaient de douleurs rotuliennes. Dans un cas on notait sur la radiographie une zone claire entre l'os et le ciment, mais sans douleur. La fonction fémoro-patellaire avant l'opération était bonne dans 3 cas, passable dans 54 et mauvaise dans 43. Après l'opération, elle était bonne 88 fois et passable 12 fois. Aussi bien la bascule que la subluxation réduisent un peu la fonction post-opératoire de l'articulation fémoropatellaire. La reconstruction de la rotule lors de l'arthroplastie »total condylar« tolère une légère malposition de la prothèse rotulienne, assure une stabilité suffisante et, habituellement, une fonction indolore.

     

Patellofemoral complications following total knee arthroplasty: Correlation with implant design and patient risk factors

Results of 211 total knee arthroplasty operations were retrospectively evaluated to identify patients with knees at greatest risk for the development of patellofemoral complications and to determine the incidence and type of patellofemoral complications associated with different patellar implants. Patellofemoral complications occurred in 27 knees (12.8%). Osteoarthritis and obesity were associated with an increased incidence of patellofemoral problems. Significantly higher rates of patellofemoral complications were noted with metal-backed patellar implants and with patellar components implanted without cement. The loosening rate with cementless fixation was 13.5%. The lowest rate of patellofemoral complications following total knee arthroplasty was obtained with all-polyethylene domed patellar components implanted with cement.     

Patellofemoral arthroplasty versus total knee arthroplasty in patients with isolated patellofemoral osteoarthritis

We identified all patients at our institution who underwent patellofemoral arthroplasty (PFA) or total knee arthroplasty (TKA) as treatment for isolated patellofemoral arthritis (PA) between January 2003 and December 2005. Twenty-three PFA and 22 TKA patients met inclusion criteria. Mean age was 60 years and 69 years, respectively (P = .01). Mean follow-up was 29 months (range, 24 to 49 months) in the PFA group and 27 months (range, 24 to 33 months) in the TKA group. Mean postoperative Knee Society Clinical Rating System scores were 89 and 90 in the PFA and TKA cohorts, respectively. Mean UCLA scores were 6.6 and 4.2, respectively (P<.0001). Mean blood loss (P = .03) and hospital stay (P = .001) were significantly lower among PFA patients. Linear regression analysis showed that blood loss, hospital stay, and functional outcomes were not affected by age as an independent variable. No significant complications occurred in the PFA group. There was one deep vein thrombosis in the TKA group. We conclude that PFA yields clinical outcomes comparable to that of TKA as treatment for isolated PA and may be a less invasive option for this select subgroup of patients.     

A posterior-stabilized total knee arthroplasty shows condylar lift-off during deep knee bends

This prospective randomized study was done to examine whether any difference in presentation of condyler lift-off exists between posterior cruciate-retaining and posterior-stabilized total knee arthroplasties. Fluoroscopic analysis of flexion kinematics under weightbearing condition was done for 18 patients who had bilateral paired total knee arthroplasties. The posterior cruciate-retaining and posterior-stabilized prostheses were from the same total knee arthroplasty series with comparable surface geometries and were implanted by one surgeon. At evaluation, five of 18 patients (28%) with posterior cruciate-retaining total knee arthroplasties had condylar lift-off, compared with 12 of 18 patients (67%) with posterior-stabilized total knee arthroplasties. Consequently, a significant difference in its incidence was seen between the groups. Condylar lift-off in posterior-stabilized knees was observed at various flexion angles, and one knee in this group had lift-off laterally and medially at different flexion angles. These findings raise concern that the higher incidence of condylar lift-off in posterior-stabilized total knee arthroplasty may lead to an increased wear rate of polyethylene associated with long-term prosthetic loosening.     

Patellofemoral complications after total knee arthroplasty: a comparison of Modular Porous-Coated Anatomic with Duracon prostheses

Clinical and radiographic analyses were used to compare results obtained in 45 patients who underwent a Modular Porous-Coated Anatomic total knee arthroplasty with results in a similar group of 45 patients who underwent a Duracon total knee arthroplasty. The surgeries were consecutively performed over an 8-month period, and follow-up evaluation averaged 63 months. The two patient groups were similar with regard to the following variables: age, sex, diagnosis, height, weight, and preoperative and postoperative activity levels. Whereas both Duracon and Modular total knee arthroplasty prostheses yielded similar results approximately 5 years after surgery, the data suggest that Duracon appears to minimize patellofemoral complications.     

Patello-femoral complications associated with total knee arthroplasty

The patello-femoral articulation accounts for a significant number of the complications that occur after total knee replacements and which require re-operation. These include problems with stability, component wear, fracture, loosening, and osteonecrosis. With careful attention to prosthetic design and surgical technique, these complications can be minimized. Guest Lecture presented at the 26th meeting of the Japanese Society for Replacement Arthroplasty in Tokyo on February 2, 1996     

A seven-year experience of data collection on the Insall-Burstein II total knee arthroplasty. A prospective study

We describe a method of audit of a type of total knee replacement, including some details of the organisational difficulties of administering multicentre studies, and draw attention to how this can be done using industrial funding without prejudicing the study. This is a prospective record of 1439 patients who had an Insall-Burstein II (IBII) prosthesis implanted between 1990 and 1994. The data were collected using the American Knee Society scoring system. A method of storing radiographs digitally at low cost is also described. The results emphasise the need for the long-term collection of data on commonly used devices implanted by a cross-section of surgeons. We conclude that for most patients the IBII cemented, posteriorly stabilised, cruciate-substituting prosthesis will relieve pain and give excellent functional results throughout the patients' remaining years with a very small incidence of revision, except in cases of infection.     

Patellofemoral function after total knee arthroplasty: gender-related differences

The purpose of the study was to evaluate patellofemoral results in 2 comparable groups of 50 patients, men and women, undergoing total knee arthroplasty. The average follow-up was 6 years. The implant was posteriorly stabilized with a dome patellar arthroplasty. The patients were studied using Knee Society knee and functional scores and the Hospital for Special Surgery (HSS) patellar score. Radiologic study included standard and weight-bearing axial views and a computed tomographic scan to assess component rotation. The 2 groups achieved satisfactory and similar knee scores; women had a significantly lower functional and patellar scores. The incidence of lateral patellar tilt, subluxation, and lateral impingement was decreased in weight-bearing axial views compared with non-weight bearing. Medial bony impingement was evident only in weight-bearing views and correlated with pain (P < .05).     

Joint line changes in cruciate-retaining versus posterior-stabilized computer-navigated total knee arthroplasty

Introduction

This study compared joint line changes and functional outcomes between cruciate-retaining (CR) and posterior-stabilized (PS) computer-navigated total knee arthroplasties (TKAs). With the increased precision offered by computer navigation, we hypothesized that there should be minimal differences in the joint line changes between the groups and thus no significant differences in the clinical outcomes.

Materials and methods

A retrospective study of 195 patients with a minimum of 2-year follow-up following primary surgery was conducted. The patients were stratified into two groups: the CR group and the PS group. The joint line changes of both groups were then compared using the Student t test. Multivariate analysis and regression modelling were then utilized to analyze the functional outcomes of both groups.

Results

CR knees had a significantly lesser mean joint line change of 1.70 mm as compared to 2.34 mm in PS knees (p = .04) but the absolute difference was only 0.64 mm. The PS group had significantly better final range of motion of 122° (±9.9°) as compared to 114° (±15.0°) in the CR group (p < .0001). There were no significant differences in the final outcome scores.

Conclusion

Although there is a significant difference statistically in the joint line changes between the groups, this difference is less than 1 mm and probably has no significant clinical impact. This is further affirmed by the fact that there was no significant difference in the clinical outcomes. The increased range seen in PS knees is probably not related to joint line changes.

Level of evidence

III.