Asymmetric patella resurfacing in total knee arthroplasty

Three hundred consecutive primary, cemented, condylar total knee arthroplasties (TKAs) were reviewed for the presence of asymmetric patella resurfacing using a postoperative Merchant or sunrise patellar radiograph. Twenty-one knees in 14 patients were found to have the patella asymmetrically resurfaced. Asymmetric resurfacing typically involved the inadvertent preferential resurfacing of the lateral facet with underresection of bone from the medial patellar facet. All patients underwent follow-up for a minimum of 5 years, with a mean follow-up of 7.5 years. Of the 21 knees, 3 revisions were required for patellar complications. One patellar component was loose on radiographs and there was marked patellofemoral pain in 6 knees. Overall, 11 of 21 knees (52%) underwent revision or were recommended for revision for patellar complications or had anterior knee pain that limited activities. Inadvertent asymmetric patella resurfacing using the kinematic condylar implant adversely affects the outcome after TKA.     

Total knee arthroplasty without patellar resurfacing in isolated patellofemoral osteoarthritis

Thirty-one patients (33 knees) with symptomatic patellofemoral osteoarthritis and minimal tibiofemoral changes underwent LCS total knee arthroplasty without patellar resurfacing. Average age was 73 years (range, 58-89 years) with a female-to-male ratio of 5:1. Average follow-up was 20 months (range, 12-40 months). All except 4 patients had grade 3 or 4 patellofemoral osteoarthritis. Preoperatively, all patients had significant knee pain. Sleep disturbance was reported in 21 patients. All but 10 patients required walking aids. Average range of motion was 108 degrees (range, 80-125 degrees ). At latest review, 21 knees were pain-free, the remaining 12 knees being described as having only occasional knee pain. Two patients continued to have night pain. Average range of motion was 104 degrees (range, 70-135 degrees ). Lateral patellar tilt improved in all but 5 knees by an average of 7 degrees (range, 1-26 degrees ). Patellar congruency improved in all but 3 knees by an average of 18% (range, 3-63%). None of the patients to date have required revision surgery. Total knee arthroplasty without patellar resurfacing is an effective option in older patients with isolated patellofemoral osteoarthritis.     

Patellofemoral complications with the Insall-Burstein II posterior-stabilized total knee arthroplasty

The Insall-Burstein and Insall-Burstein II posterior-stabilized (I-B II PS) prostheses have been reported to have a high prevalence of patellar complications. This is a prospective, consecutive study of 118 primary total knee arthroplasties in 82 patients with the I-B II PS prosthesis implanted by 1 surgeon, using a specific technique for patellar resurfacing. The mean follow-up time was 4.0 years (range, 2-8 years). Clinical evaluation was performed using a standard knee score system with specific additional evaluation of the patellofemoral joint. Radiographs were evaluated for fracture, loosening, and subluxation. Ninety-four knees (80%) were rated excellent, 21 knees (17%) good, and 3 knees (3%) fair. The mean flexion was 112 degrees postoperative. No knee required reoperation for the patellofemoral joint. There were 2 nondisplaced and 1 minimally displaced patellar fractures treated nonoperatively, no patellar clunk syndrome, and no subluxations. Using the patellar evaluation system, 109 knees had no anterior knee pain, 7 knees had mild pain, and 2 knees (1 patient) had moderate-to-severe pain only with rising from a chair. Patellofemoral crepitus with active flexion-extension in the seated position was noted in 16 knees (14%) but was painful in only 2 knees (1 patient). With this technique for patellar resurfacing with this prosthesis, patellofemoral complications were only 4.2%, and no knee required reoperation for the patella or for loosening. With attention to operative technique, patellofemoral resurfacing with this posterior-stabilized total knee arthroplasty can be highly successful.     

Advantage of Minimal Anterior Knee Pain and Long-term Survivorship of Cemented Single Radius Posterior-Stabilized Total Knee Arthroplasty without Patella Resurfacing

BackgroundThe single radius total knee prosthesis was introduced with the advantage of reduced patellar symptoms; however, there is no long-term follow-up study of the same. The purpose of this study was to determine the survival rate of single radius posterior-stabilized total knee arthroplasty and patellofemoral complication rates in a consecutive series.MethodsSeventy-one patients (103 knees) who underwent arthroplasty without patellar resurfacing using a single radius posterior-stabilized total knee prosthesis were followed up for a minimum 10 years. Clinical evaluation using Knee Society knee and function scores and radiologic evaluation were performed at regular intervals. Anterior knee pain as well as patellofemoral complications were evaluated with a simple questionnaire. The Kaplan-Meier product-limit method was used to estimate survival.ResultsSeventeen patients (23 knees) were excluded due to death (12 knees) or lost to follow-up (11 knees). Of the 80 knees enrolled, all femoral components and 78 tibial components were well fixed without loosening at final follow-up. Two revisions were performed because of tibial component loosening and periprosthetic joint infection. One patient with tibial component loosening refused to have revision surgery. No obvious tibial insert polyethylene wear was observed. The survivorships at 132 months were 96.7% using revision or pending revision as end points. Anterior knee pain was present in 6 patients (6 knees, 7.5%) at the latest follow-up. No patellofemoral complication requiring revision was encountered.ConclusionsThe single radius posterior-stabilized total knee prosthesis demonstrated an excellent minimum 10-year survivorship. The low rates of implant loosening and 7.5% of anterior knee pain as a patellofemoral complication are comparable with those reported for other modern total knee prosthesis.     

Early patellofemoral revision following total knee arthroplasty

A consecutive series of 289 Miller-Galante (Zimmer, Warsaw, IN) total knee arthroplasties were studied, with particular reference to the patellofemoral joint. Sixteen knees were initially excluded; the remaining 273 arthroplasties were followed for 14 to 44 months. Thirty patients (11%) had patellofemoral pain. Twenty patients (7.3%) had revision patellofemoral surgery. Fourteen patients had revision surgery for patellar maltracking, of which 10 had resolution of their symptoms, 2 were improved, 1 had no change, and 1 developed a prosthetic infection. Six patients who had no evidence of patellar maltracking had revision surgery with a cemented metal-backed patellar component. Only two of these patients had symptom improvement from their revision surgery. A higher than usual incidence of patellar maltracking (5%) is reported. The first-generation Miller-Galante femoral component may contribute to the relative instability of patellofemoral tracking. Those patients with patellar maltracking were greatly improved by revision surgery; the results of revision surgery for anterior knee pain without associated patellar maltracking were disappointing.     

全膝关节置换术后髌骨的X线改变

[目的]探讨不置换髌骨的全膝关节置换术后髌骨的X线变化。[方法]对1999年～2004年间所进行的51例64个膝关节假体进行随访,常规不置换髌骨。平均年龄68.5岁(57～78岁),平均随访4.8年(2.5～8年)。在X线正侧位片和髌骨轴位片观察病人髌骨的退变、髌骨外移和倾斜程度的变化。[结果]手术后髌骨倾斜和外移均明显改善。随时间延长,大多数髌骨轨迹居中,没有明显退变。最常见的X线改变有髌骨上下极和外侧面增生,部分髌骨轨迹出现恶化。髌股关节的症状与髌骨的退变无明确相关。[结论]不置换髌骨的膝关节置换术后,髌骨的轨迹可得到明显改善,髌骨不会出现明显退变。     

Arthroscopic Treatment of Patellar Clunk and Synovial Hyperplasia After Total Knee Arthroplasty

Patellofemoral pain, crepitus, and locking are infrequent symptoms after total knee arthroplasty (TKA). We performed a retrospective review of 25 patients who underwent arthroscopic debridement after primary TKA to treat the patellar clunk syndrome (15 knees) or patellofemoral synovial hyperplasia (10 knees). After surgery, patient-reported knee pain and crepitus as well as Knee Society knee and function scores improved in both groups. Postoperative knee range of motion remained unchanged. Arthroscopic debridement of symptomatic patellofemoral synovium after TKA is a safe and effective procedure.     

Postoperative patellar complications with or without lateral release during total knee arthroplasty

Between 1975 and 1984, 84 knees in which an intraoperative lateral release had been performed with total knee arthroplasty (TKA) were compared with 471 knees that, having sufficient patellar tracking at the time of surgery, had not required a lateral release. The lateral superior geniculate artery was routinely sacrificed in all knees in which a lateral release was necessary. The results showed no complications associated with a possible loss of blood supply secondary to the lateral release. No increased evidence of osteonecrosis, patellar bone-cement radiolucency, or patellar fracture was discovered. Clinically, there was no difference in pain, ambulation, or range of motion. Seventeen patellar fractures (3.6%) were observed in patients for whom a lateral release had not been performed, yet only one patellar fracture (1.5%) was encountered among the patients who had required a lateral release. In TKA, lateral release was associated with a relatively high degree of patellar tilting.     

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.     

Prospective analysis of Sheehan total knee arthroplasty

In a prospective study, the clinical results of 64 Sheehan total knee arthroplasties (TKA) were reviewed in 52 patients, with an average follow-up period of five and one-half years. Like most prosthetic designs in use in 1975, the Sheehan prosthesis did not incorporate patellar resurfacing. The initial clinical success achieved without patello-femoral replacement may become less acceptable with longer follow-up periods. Seventy-four percent of the patients in this study had complete relief of pain or mild discomfort not requiring analgesics. With patellar resurfacing as a secondary procedure in three additional cases, the percent successful results increased to 81%. Five knees (12%) required additional surgery, one because of infection, two because of secondary component failure, and two for loosening. The lack of patellofemoral replacement and prospective failure of both tibial and femoral components, possibly due to high stress-loading in a relatively small surface area, have led to the use of other newer TKA designs.     

Clinical outcome of revision of the patellar component in total knee arthroplasty. A 2- to 7-year follow-up study

The objectives of this study were to determine the relationship between the thickness of the residual patellar bone and the composite patella-patellar component, and the clinical outcome in patients who had undergone revision total knee arthroplasty (TKA) with a biconvex patellar component. Clinical outcome after at least a 2-year follow-up was determined using the Knee Society pain and functional scores, and radiographically, with the thicknesses of the patellar bone and composite measured in 23 knees (22 patients). The thickness of the patellar bone after preparation for a biconvex patellar component was significantly less for revised patellae (average, 5.0 mm) than the primary patellae (average, 7.9 mm; P < 0.01). Differences in thickness between preoperative patellae, primary composites, and revision composites did not significantly affect postoperative results. There were no patellar fractures, despite the relatively thin bone remnant in the revision patients. Radiolucency was observed in 8% of the revisions. A patella with a thickness of residual bone of as little as 5 mm can provide favorable clinical results in revision TKA with restoration of the composite thickness of the patella achieved using a thick but small-diameter biconvex patellar component. Received for publication on Feb. 4, 1998; accepted on Aug. 20, 1998     

Resection arthroplasty for failed patellar components

A total of 1,401 primary total knee arthroplasties (TKA) were reviewed; 44 (3.2%) had at least the patellar component revised. Nine of these knees (eight patients) had insufficient bone stock to allow reimplantation of another patellar component. Clinical data on the nine knees were obtained with recent follow-up evaluation, review of their medical records and radiographs. Evaluation included Hospital for Special Surgery (HSS) scores. Average follow-up was 4 years and 7 months, 2-year range (2 months to 8 years and 4 months). Common factors found in these nine knees included: thin patella after primary TKR status, osteoarthritis, good range of motion and patella alta. Results were good to excellent in seven knees and fair in two. The untoward associations with patellectomy such as quadriceps lag, extension weakness and anterior knee pain were not experienced. Resection of the patellar component, without reimplantation, is an acceptable alternative in revision TKA lacking adequate remaining bone stock.     

Influence of Patellar Morphology Classified by Wiberg Classification on Knee Joint Function and Patellofemoral Tracking After Total Knee Arthroplasty Without Patellar Resurfacing

BackgroundTo evaluate the influence of patellar morphology on knee joint function and patellofemoral tracking in patients with primary osteoarthritis after total knee arthroplasty (TKA) without patellar resurfacing.MethodsWe performed a retrospective study of 156 patients with primary osteoarthritis who underwent TKA without patellar resurfacing from April 2018 to July 2019. As per Wiberg classification, patients were divided into Wiberg type I (group A, n = 38), II (group B, n = 88), and III (group C, n = 30) groups. The clinical data, postoperative follow-up data, and radiological data between three groups were compared.ResultsThere was no statistically significant difference in the HSS score and Feller score between the three groups before surgery and at each follow-up point after surgery (P > .05). At the last follow-up, there were no significant differences in the height and relative thickness of the patella between the three groups (P > .05). However, the incidence of anterior knee pain was significantly higher in group C than in the group B (P < .05). The patellar tilt angle was significantly larger in group C than in the groups A and B (both P < .05). The patellar facet angle was significantly larger in group A than in group B and C, which was also significantly larger in group B than in group C (both P < .05).ConclusionPatients with three different morphologic types of the patella both exhibited improved knee joint function after TKA, however, patients with Wiberg type Ⅲ patella were more prone to have poor patellofemoral tracking and anterior knee pain after surgery.     

髌骨合理设计在全膝关节置换中的临床效果

目的探讨髌骨合理设计后重塑在全膝关节置换(TKA)中的临床效果。方法根据股骨假体滑动轨迹及所需置换髌骨的形态,对56例TKA患者(72膝)术中进行髌骨合理设计并重塑,观察患者术后的关节活动度及疼痛情况,用KSS膝关节评分系统评定治疗效果。结果 56例均获得随访,时间6~18个月。仅1例患者膝关节活动度70°,活动较差,但疼痛明显减轻;其余患者屈曲活动度在0°~110°。KSS评分:优69膝,良2膝,中1膝,优良率达到98.6%。结论术中根据股骨假体滑动轨迹对髌骨合理设计并重塑,可以使未进行髌骨置换的TKA患者取得满意的治疗效果。     

Effect of femoral component design on unresurfaced patellas in knee arthroplasty

Three total knee designs were evaluated to test the hypothesis that femoral component design affects the clinical and mechanical functions of the unresurfaced patella after total knee arthroplasty. Patients with the Ortholoc II, Advantim, and Profix femoral components were followed up for as many as 14 years and revision rate, anterior knee pain, and generalized knee pain were compared. A laboratory protocol was devised to evaluate pressure in the patellofemoral joint of knees from cadavers with a pressure-sensitive transducer using the same three designs at various degrees of knee flexion. Thirty Ortholoc II knee components were followed up for 14 years. Nineteen patients (63%) had severe anterior knee pain and 15 patients (50%) had reoperation to resurface the patella within 2 years. Two hundred one patients (222 knees) with Advantim components were followed up for 10 years and 305 patients (330 knees) with Profix components were followed up for 5 years. No patients with these two knee designs had severe anterior knee pain or reoperation for patellar resurfacing. A significantly higher rate of mild anterior knee pain was seen in the patients with Advantim components than in the patients with Profix components. No apparent relationship was seen between the severity of patellar wear found at the time of surgery and the incidence of anterior knee pain. Patients with rheumatoid arthritis receiving either the Advantim or Profix knee component performed as well as patients with osteoarthritis when the patella was not resurfaced. Pressure was significantly higher in the patellofemoral joints of the laboratory knee specimens with Ortholoc II components than in the specimens with either the Advantim or Profix components. The specimens with Advantim components had significantly higher pressure than did the specimens with normal knees, and the specimens with Profix components differed little from those with normal knees.     

Influence of Total Knee Arthroplasty on Patellar Kinematics and Patellofemoral Pressure

Background

Patellofemoral complications are one of the main problems after total knee arthroplasty (TKA). The design of the TKA component may affect the patellar biomechanics, which may be associated with this postoperative complication. The purpose of this study was to assess the influence of TKA and prosthesis designs on the patellar kinematics and patellofemoral pressure.

The effect of a tourniquet on intraoperative patellofemoral tracking during total knee arthroplasty

A prospective investigation was performed on the effect of the tourniquet on intraoperative patellofemoral tracking during primary total knee arthroplasty (TKA). A total of 75 TKAs in 67 patients were performed by 1 surgeon in a consecutive series using the same technique. Using strict criteria, patellar tracking was assessed both before and after tourniquet release. Patients were placed into 1 of 3 groups: Group I were knees that tracked properly both before and after tourniquet release. Group II were knees that maltracked with the tourniquet inflated and subsequently corrected with the tourniquet released. Group III were knees that maltracked both before and after tourniquet release, therefore requiring a lateral release. Knees were categorized as group I, 34 of 75 (45.3%); group II, 36 of 75 (48.0%); and group III, 5 of 75 (6.7%). Using this criterion, lateral release was avoided in all group II knees. Tourniquet application alters intraoperative patellofemoral tracking during TKA. When contemplating lateral release, tourniquet deflation and reevaluation of patellofemoral tracking should be considered.     

Total knee replacement with and without patellar resurfacing: a prospective, randomised trial using the profix total knee system.

We have examined the differences in clinical outcome of total knee replacement (TKR) with and without patellar resurfacing in a prospective, randomised study of 181 osteoarthritic knees in 142 patients using the Profix total knee system which has a femoral component with features considered to be anatomical and a domed patellar implant. The procedures were carried out between February 1998 and November 2002. A total of 159 TKRs in 142 patients were available for review at a mean of four years (3 to 7). The patients and the clinical evaluator were blinded in this prospective study. Evaluation was undertaken annually by an independent observer using the knee pain scale and the Knee Society clinical rating system. Specific evaluation of anterior knee pain, stair-climbing and rising from a seated to a standing position was also undertaken. No benefit was shown of TKR with patellar resurfacing over that without resurfacing with respect to any of the measured outcomes. In 22 of 73 knees (30.1%) with and 18 of 86 knees (20.9%) without patellar resurfacing there was some degree of anterior knee pain (p = 0.183). No revisions related to the patellofemoral joint were performed in either group. Only one TKR in each group underwent a re-operation related to the patellofemoral joint. A significant association between knee flexion contracture and anterior knee pain was observed in those knees with patellar resurfacing (p = 0.006).     

Edge loading of patellar components after total knee arthroplasty.

Patellofemoral joint kinematics, contact areas, contact pressures, and contact patterns were assessed after total knee arthroplasty (TKA) using human cadaver knees. Two contemporary TKA systems with anatomic patellofemoral joints were implanted and tested under anatomically based loading conditions. An electromagnetic tracking system was used to evaluate patellofemoral kinematics, and Fuji pressure-sensitive film was used to determine contact areas, pressures, and patterns. Edge loading of patellar components was observed at higher knee flexion angles with both TKA systems. Peak contact pressures seen at the regions of edge loading exceeded the yield strength of ultra-high-molecular weight polyethylene. Efforts to reduce edge loading and contact pressures may decrease the incidence of patellofemoral joint complications and component failure after TKA.     

A clinical comparison of patellar tracking using the transepicondylar axis and the posterior condylar axis

Two different methods for femoral component rotation in total knee arthroplasty (TKA) were compared with regard to the need for lateral retinacular release and 3-year follow-up knee society scores of both patellofemoral function and 3-year radiographs of the patella. The posterior condylar axis was used in 1322 consecutive primary TKAs, and the transepicondylar axis (TEA) was used in 1059 consecutive primary TKA. A significant decrease in lateral retinacular release was observed from 56.9% (752 knees) using the posterior condylar axis down to 12.3% (130 knees) using the TEA. No significant differences in knee society scores were observed between the 2 groups with regard to stair climbing, pain, patella radiographs, or range of motion. Routine use of the TEA is recommended for determining femoral component rotation in TKA.