Selective patellar nonresurfacing in total knee arthroplasty. 10 year results.

Patella nonresurfacing in total knee arthroplasty was reviewed retrospectively in 49 knees (42 patients). Thirteen patients (17 knees) died leaving 29 patients (32 knees) in the final study group. The minimum length of followup was 10 years and averaged 11.7 years (range, 10-13.4 years). The diagnosis was primary osteoarthritis in 26 knees, posttraumatic arthritis in four, osteonecrosis in one, and Paget's disease in one. Patients were evaluated using the Knee Society score, a patella score, and radiographs. The mean Knee Society score improved from 52.8 to 87.5 points postoperatively and functional score improved from 57.5 to 84.5 points postoperatively. Anterior knee pain was reported in six knees (20%). Only one patient required secondary resurfacing of the patella because of postoperative anterior knee pain. No significant correlation was found between anterior knee pain and patellofemoral joint space, patellar sclerosis, Insall-Salvati ratio, patellar tilt, gender, obesity, or age. Based on the need for secondary patellar resurfacing because of anterior knee pain, the 10-year survival was 97.5%. At minimum 10-year followup, retaining the patella in total knee arthroplasty in selected patients with osteoarthritis of the osteoarthritic knee can yield acceptable results.     

Total knee arthroplasty in patients with isolated patellofemoral arthritis.

The current study evaluated the results of total knee arthroplasty for the treatment of isolated patellofemoral degenerative arthritis. Between 1980 and 1997, 31 total knee arthroplasties were done in 24 patients with advanced, isolated patellofemoral arthritis. The average followup was 5.2 years (range, 2-12 years). There was a significant improvement in the mean preoperative Knee Society pain and function scores. Twenty-one knees required a lateral retinacular release and three knees required additional formal proximal realignment at the time of the total knee arthroplasty. There were three reoperations in this series including, manipulation for poor motion in one patient; revision of a loose patellar component in one patient; and extensor mechanism realignment in the third patient. At midterm followup, total knee arthroplasty proved to be reliable and durable in alleviating pain and improving function in this group of patients with isolated, advanced patellofemoral arthritis. Surgeons should be made aware, however, that resurfacing of the patella and balancing the extensor mechanism for patients with isolated patellofemoral arthritis can be demanding technically as evidenced by the high rate of asymmetrically resurfaced patellas, the high rate of lateral retinacular release, and formal realignment procedures.     

Patellar resurfacing in total knee arthroplasty. A prospective,randomized study

BACKGROUND: Anterior knee pain following total knee arthroplasty is a common complaint and typically is attributed to the patellofemoral joint. The purpose of the present study was to compare the outcome of resurfacing and nonresurfacing of the patella, particularly with regard to anterior knee pain, and to clarify the indications for patellar resurfacing at the time of total knee arthroplasty. METHODS: We performed a prospective, randomized study of 514 consecutive primary press-fit condylar total knee replacements. The patients were randomized to either resurfacing or retention of the patella. They were also randomized to either a cruciate-substituting or a cruciate-retaining prosthesis as part of a separate trial. The mean duration of follow-up was 5.3 years (range, two to 8.5 years), and the patients were assessed with use of the Knee Society rating, a clinical anterior knee pain score, and the British Orthopaedic Association patient-satisfaction score. The assessment was performed without the examiner knowing whether the patella had been resurfaced. At the time of follow-up, there were 474 knees. Thirty-five patients who had a bilateral knee replacement underwent resurfacing on one side only. RESULTS: The overall prevalence of anterior knee pain was 25.1% (fifty-eight of 231 knees) in the nonresurfacing group, compared with 5.3% (thirteen of 243 knees) in the resurfacing group (p < 0.0001). There was one case of component loosening. Ten of eleven patients who underwent secondary resurfacing had complete relief of anterior knee pain. The overall postoperative knee scores were lower in the nonresurfacing group, and the difference was significant among patients with osteoarthritis (p < 0.01). There was no significant difference between the resurfacing and nonresurfacing groups with regard to the postoperative function score. Patients who had a bilateral knee replacement were more likely to prefer the resurfaced side. CONCLUSIONS: As the present study showed a significantly higher rate of anterior knee pain following arthroplasty without patellar resurfacing, we recommend patellar resurfacing at the time of total knee replacement when technically possible.     

Patellar resurfacing in total knee arthroplasty: a prospective, randomized trial

BACKGROUND: The management of the patella in total knee arthroplasty is still problematic. We aimed to identify differences in the clinical outcome of total knee arthroplasty according to whether or not patellar resurfacing had been performed in a prospective, randomized study of 220 osteoarthritic knees. METHODS: Two hundred and twenty total knee arthroplasties in 201 patients were randomly assigned to be performed with either resurfacing or retention of the patella, and the results were followed for a mean of forty-eight months (range, thirty-six to seventy-nine months) in a double-blind (both patient and clinical evaluator blinded), prospective study. Evaluation was performed annually by an independent observer and consisted of assessment with the Knee Society clinical rating system, specific evaluation of anterior knee pain, a stair-climbing test, and radiographic examination. RESULTS: Fifteen (12%) of the 128 knees without patellar resurfacing and nine (10%) of the ninety-two knees with patellar resurfacing underwent a revision or another type of reoperation related to the patellofemoral articulation. This difference was not significant (chi square with one degree of freedom = 0.206, p = 0.650). At the time of the latest follow-up, there was a significantly higher incidence of anterior pain (chi square with one degree of freedom = 5.757, p = 0.016) in the knees that had not had patellar resurfacing. CONCLUSIONS: Patients who underwent patellar resurfacing had superior clinical results in terms of anterior knee pain and stair descent. However, anterior knee pain still occurred in patients with patellar resurfacing, and nine (10%) of the ninety-two patients in that group underwent a revision or another type of reoperation involving the patellofemoral joint. Weight but not body mass index was associated with the development of anterior knee pain in the patients without patellar resurfacing, a finding that suggests that patellofemoral dysfunction may be a function of joint loading rather than obesity.     

Patellar resurfacing in total knee arthroplasty. A prospective, randomized, double-blind study with five to seven years of follow-up

BACKGROUND: Whether to resurface the patella during a primary total knee arthroplasty performed for the treatment of degenerative osteoarthritis remains a controversial issue. Parameters that have been suggested as being useful in guiding this decision include patient height and weight, the presence of anterior knee pain preoperatively, and the grade of chondromalacia encountered intraoperatively. The purpose of this study was to determine whether these parameters were predictive of the clinical result following total knee arthroplasty with or without patellar resurfacing. METHODS: Eighty-six patients (118 knees) undergoing primary total knee arthroplasty for the treatment of osteoarthritis were enrolled in a prospective, randomized, double-blind study. All patients received the same posterior-cruciate-sparing total knee prosthetic components. Patients were randomized to treatment with or without resurfacing of the patella. Evaluations consisted of the determination of a Knee Society clinical score, the completion of a patient satisfaction questionnaire, specific questions relating to patellofemoral symptoms, and radiographs. Sixty-seven patients (ninety-three knees) were followed for a minimum of five years (range, sixty to eighty-four months; average, 70.5 months). RESULTS: With the numbers available, there was no significant difference between the groups treated with and without resurfacing with regard to the overall Knee Society score or the pain and function subscores. Obesity, the degree of patellar chondromalacia, and the presence of preoperative anterior knee pain did not predict postoperative clinical scores or the presence of postoperative anterior knee pain. CONCLUSIONS: The occurrence of anterior knee pain could not be predicted with any clinical or radiographic parameter studied. On the basis of these results, it seems likely that postoperative anterior knee pain is related either to the component design or to the details of the surgical technique, such as component rotation, rather than to whether or not the patella is resurfaced.     

Resurfacing versus not resurfacing the patella in total knee arthroplasty: 8- to 10-year results

Patellar resurfacing in total knee arthroplasty is a topic debated in the literature. Concerns include fracture, dislocation, loosening, and extensor mechanism injury. Residual anterior knee pain has been reported when the patella is not resurfaced. One hundred patients with osteoarthritic knees were prospectively randomized to either have their patella resurfaced or left not resurfaced. All patients were treated with a single prosthesis that featured an anatomically designed patellofemoral articulation (Anatomic Medullary Knee, DePuy, Warsaw, IN) Two patients in the unresurfaced group and one in the resurfaced group required repeat surgery for patellofemoral complications. At 8- to 10-year follow-up evaluations, Knee Society Clinical Ratings scores were not different between the 2 groups. Rates of anterior knee pain with walking and stair climbing were significantly less in the resurfaced group. Eighty percent of patients with a resurfaced patella were extremely satisfied with their total knee arthroplasty versus 48% without patellar resurfacing. When satisfied and extremely satisfied patients were grouped together, there was no difference between the 2 groups.     

Patella resurfacing in posterior stabilised total knee arthroplasty: a follow-up study in 56 patients

Patellar resurfacing in total knee arthroplasty (TKA) remains controversial. This study evaluates the results of resurfacing and non-resurfacing of the patella. Fifty-six patients with osteoarthritis (OA) of the knee were enrolled in a prospective randomised clinical trial using a posterior-stabilised TKA. Evaluations were done preoperatively and after 1, 3, 6, 12 and 24 months. Disease specific (Knee Society Score or KSS) and functional (patella-related activities) outcomes were measured. Patient satisfaction and anterior knee pain questionnaires were completed. No patients were lost to follow-up. No significant differences were found between groups with regard to the clinical part of the Knee Society score (KSS) not even in obese patients, the ability of performing daily activities involving the patellofemoral joint, and patient satisfaction. Significant differences were found regarding the functional section of the KSS, passive flexion, anterior knee pain and patellar tilt and subluxation. In conclusion, the authors believe that, for the implant studied, patellar resurfacing can be indicated.     

Patellar resurfacing reduces pain after TKA for juvenile rheumatoid arthritis

Influence of patellar resurfacing after knee replacement and the frequency of patella infera and its relation to the postoperative appearance of the knee pain were assessed in patients with juvenile rheumatoid arthritis. Seventy-seven total knee arthroplasties using the AGC prosthesis with nonconstrained components were done on 52 patients with a mean followup of 7.3 years (range, 3-13 years). Anterior knee pain was present in 14 of 30 patients (47%) with an unreplaced patella and in two of 18 patients (11%) with patella resurfacing. The patella was replaced in 18 patients (35%) and in 23 of 77 knees (30%). Neither revision surgery of implanted patellar components nor any later resurfacing of an unreplaced patella were done during the followup. Preoperatively using the Insall-Salvati ratio, the majority of knees (54 of 77) had a low-riding patella. Patella infera occurred commonly in patients with juvenile rheumatoid arthritis. No connection between patella infera and anterior knee pain was found.     

全膝关节置换术中髌骨面修整与髌骨置换的比较研究

目的比较全膝关节置换术髌骨面修整和髌骨置换的临床结果。方法2002年1月至12月对60例（60膝）行初次全膝关节置换术的骨性关节炎患者进行前瞻性、随机化研究。所有患者接受相同的后交叉韧带替代型全膝关节假体（PFC）,患者随机行髌骨面修整（髌骨面修整组）或髌骨置换（髌骨置换组）。58例患者平均随访54个月（40～60个月）,对其进行临床评价,包括膝关节协会评分（KSS）、膝关节活动度（ROM）、患者满意度和X线检查。结果两组患者KSS总评分（P=0．12）、KSS疼痛评分（P=0．90）、患者满意度（P=0．22）无明显差异;两组术后膝前痛的发生率均为10％亦无明显差异。两组ROM（P=0．028）和KSS功能评分（P=0．0098）差异有统计学意义。结论全膝关节置换术不论是髌骨面修整还是髌骨置换均能明显减轻疼痛和改善功能。术后膝前痛可能与假体设计和手术技术有关,并非与是否置换髌骨有关。     

One-peg versus three-peg patella component fixation in total knee arthroplasty.

In many designs of total knee arthroplasty, the patella with one central peg has been replaced by a patella with three small pegs for cement fixation. There have been recent reports of failure of this design. This is a prospective, consecutive study of two types of patella component fixation in 228 posterior-stabilized knee arthroplasties done by one surgeon. A central peg all-polyethylene component was used for 84 consecutive knees in 63 patients (Group A) and a three-peg patella was used for the next 144 consecutive knees in 99 patients (Group B). The mean followup was 6.7 years (range, 2-10 years) for Group A and 3.5 years (range, 2-6 years) for Group B. Except for the patellar component fixation, all knees had the same posterior-stabilized prosthesis using a specific protocol for patellar resurfacing. No patient required reoperation for a patellofemoral complication. The prevalence of patella fracture was higher in Group A, 4.7% (four knees), compared with 2.1% (three knees) in Group B, but this difference was not statistically significant. The presence of anterior knee pain referable to the patella was 7.1% (five patients, six knees) in Group A (one patient with two knees had severe anterior knee pain) and 9% (13 knees in 13 patients) in Group B. There was no patella clunk syndrome, subluxation, or fracture of a fixation peg in either group. With this specific protocol for patella resurfacing, there was a higher rate of complications with the one central peg patella (4.7%) than with the three-peg patella (2.1%), but this did not reach statistical significance. The results do not support an increased risk of component failure with this three-peg patella design, but do not, at this length of followup, show any significant advantage of three-peg fixation.     

Advantages of patellar resurfacing in total knee arthroplasty

Complications of patellar resurfacing in total knee arthroplasty have rekindled the interest of many surgeons in patellar retention. In a prospective study 20 randomly selected patients of 40 underwent patellar resurfacing in combination with their total knee arthroplasty. The other 20 patients were left with an unresurfaced patella. Within 24 months of follow-up, the advantages of patellar resurfacing could be seen according to the Knee Society Score. Especially in advanced osteoarthritis of the knee joint, the patients achieved better scores in climbing stairs and in function. The superior functional results are arguments for patellar resurfacing, at least in knees with advanced osteoarthritis.     

Outcomes of Cemented Total Knee Arthroplasty for Secondary Osteonecrosis of the Knee

BackgroundSecondary osteonecrosis of the knee (SOK) generally occurs in relatively young patients; at advanced stages of SOK, the only viable surgical option is total knee arthroplasty (TKA). We conducted a retrospective study to investigate implant survivorship, clinical and radiographic outcomes, and complications of contemporary cemented bicompartmental TKA with/without patellar resurfacing for SOK.MethodsThirty-eight cemented TKAs in 27 patients with atraumatic SOK, mean age 43 years (17 to 65), were retrospectively reviewed. Seventy-four percent had a history of corticosteroid use, and 18% had a history of alcohol abuse. Patellar osteonecrosis was coincidentally found in six knees (16%), and all were asymptomatic without joint collapse. The mean followup was 7 years (2 to 12). Knee Society Score (KSS) and radiographic outcomes were evaluated at 6 weeks, 1 year, then every 2 to 3 years.ResultsNinety-two percent had implant survivorship free from revision with significant improvement in KSS. Causes of revision included aseptic tibial loosening (one), deep infection (one), and instability with patellofemoral issues (one). Four of six cases also with patellar osteonecrosis received resurfacing, including one with periprosthetic patellar fracture after minor trauma, with satisfactory clinical results after conservative treatment. None of the unrevised knees had progressive radiolucent lines or evidence of loosening. An unresurfaced patella, use of a stem extension or a varus-valgus constrained prosthesis constituted 18%, 8% and 3%, respectively.ConclusionCemented TKAs with selective stem extension in patients with SOK had satisfactory implant survivorship and reliable outcomes. Secondary osteonecrosis of the patella should be carefully evaluated prior to operation.     

The Richards type II patellofemoral arthroplasty: 26 cases followed for 1-20 years

We followed 26 Richards type II patellofemoral arthroplasties in 24 patients (19 women) for a mean of 11 (1-20) years. Their mean age was 59 (22-90) years. The preoperative diagnoses were primary patellofemoral arthrosis in 17 cases and secondary arthrosis in 9 (8 malalignment, 1 patellar fracture). Patellectomy was later performed for persistent pain or patellar malalignment in 3 cases and a conversion to a total knee arthroplasty for progressive tibio-femoral degeneration or patella malalignment in 2. The mean Knee Society knee score for 21 knees at follow-up was 90 (65-100) points. The patients rated the results of surgery in 9 knees as excellent, 7 good, 4 improved, and 1 unimproved at follow-up. None of the implants showed signs of loosening or infection. The Richards type II patellofemoral arthroplasty yields acceptable long-term results in patients with isolated end-stage patellofemoral osteoarthrosis. Patient selection and patella alignment are important.     

The Richards type II patellofemoral arthroplasty: 26 cases followed for 1-20 years

We followed 26 Richards type II patellofemoral arthroplasties in 24 patients (19 women) for a mean of 11 (1-20) years. Their mean age was 59 (22-90) years. The preoperative diagnoses were primary patellofemoral arthrosis in 17 cases and secondary arthrosis in 9 (8 malalignment, 1 patellar fracture). Patellectomy was later performed for persistent pain or patellar malalignment in 3 cases and a conversion to a total knee arthroplasty for progressive tibio-femoral degeneration or patella malalignment in 2. The mean Knee Society knee score for 21 knees at follow-up was 90 (65-100) points. The patients rated the results of surgery in 9 knees as excellent, 7 good, 4 improved, and 1 unimproved at follow-up. None of the implants showed signs of loosening or infection. The Richards type II patellofemoral arthroplasty yields acceptable long-term results in patients with isolated end-stage patellofemoral osteoarthrosis. Patient selection and patella alignment are important.     

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.     

The Richards type II patellofemoral arthroplasty: 26 cases followed for 1-20 years.

We followed 26 Richards type II patellofemoral arthroplasties in 24 patients (19 women) for a mean of 11 (1-20) years. Their mean age was 59 (22-90) years. The preoperative diagnoses were primary patellofemoral arthrosis in 17 cases and secondary arthrosis in 9 (8 malalignment, 1 patellar fracture). Patellectomy was later performed for persistent pain or patellar malalignment in 3 cases and a conversion to a total knee arthroplasty for progressive tibio-femoral degeneration or patella malalignment in 2. The mean Knee Society knee score for 21 knees at follow-up was 90 (65-100) points. The patients rated the results of surgery in 9 knees as excellent, 7 good, 4 improved, and 1 unimproved at follow-up. None of the implants showed signs of loosening or infection. The Richards type II patellofemoral arthroplasty yields acceptable long-term results in patients with isolated end-stage patellofemoral osteoarthrosis. Patient selection and patella alignment are important.     

Patellar Resurfacing in Primary Total Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials

BackgroundThe management of the patella during total knee arthroplasty (TKA) remains controversial. The aim of this study is to evaluate the evidence regarding the use of patellar resurfacing in TKA.MethodsA meta-analysis of randomized controlled trials (RCTs) was performed to compare outcomes between knees receiving patellar resurfacing vs those not receiving resurfacing during primary TKA. Outcomes of interest were the Knee Society Scores, reoperation rates, anterior knee pain, patient satisfaction, Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score subscores, and range of motion.ResultsTwenty RCTs met all eligibility criteria and were included in the analysis. There were statistically significant differences favoring the resurfaced group in the knee component and functional component of Knee Society Scores that were not clinically significant. There was an increased risk of reoperation among knees that did not receive resurfacing with number needed to treat to prevent one case of reoperation of 25 knees (for reoperation for any reason) and 33 knees (for reoperation for anterior knee pain). There were no statistically significant differences in any other outcomes.ConclusionThe only clear relationship is that knees that do not receive patellar resurfacing are more likely to receive reoperation, most often for secondary resurfacing. However, the disease burden of differing complication profiles associated with resurfacing and nonresurfacing groups remains unclear. Continuing to collect data from large, well-designed RCTs would be beneficial in guiding management of the patella during TKA.     

The role of patellar resurfacing in total knee arthroplasty

The ideal treatment of the patella in primary total knee arthroplasty (TKA) for osteoarthritis (OA) remains unclear. Although data exist in the literature to support either resurfacing or not resurfacing the patella, evidence continues to emerge that unresurfaced patellas deteriorate with time. Recent prospective, randomized studies also favor patellar resurfacing over retaining the native patella, reporting reoperation rates to convert unresurfaced to resurfaced patellas exceeding those for complications after patellar resurfacing. In addition, the incidence of residual patellofemoral pain after secondary resurfacing is substantially higher than when patellofemoral resurfacing is done primarily. Patient selection criteria are critical in the decision-making process. Patellofemoral complications, the greatest argument against resurfacing, have been diminished with improved surgical techniques and implant design.     

膝关节骨关节炎患者初次全膝关节置换术中选择髌骨置换的Meta分析

目的探讨膝关节骨关节炎(OA)进行初次全膝关节置换术(TKA)中选择髌骨置换与否的疗效,评价两种不同治疗选择的差异。方法检索Medline、Embase、Cochranelibrary、CBM,收集膝关节OA行初次TKA术中髌骨置换与否的临床对照试验,提取数据分析,采用RevMan5.0.18进行Meta分析。结果纳入8个前瞻性随机对照试验,共822例手术,其中髌骨置换组373例,髌骨非置换组444例。髌骨置换与非置换组比较,前膝痛与KSS评分均无明显的统计学意义(P0.5),置换组的因髌股关节问题而再次手术率低于非置换组[RR=0.53,95%CI(0.29,0.96),P=0.04],但置换组再次手术的原因除了常见的前膝痛,还包括髌骨假体相关的并发症。结论膝关节OA的患者行初次TKA术中选择髌骨置换与否的前膝痛与KSS评分无明显的统计学意义,置换组的因髌股关节问题再次手术率低于非置换组,但置换组再次手术的复杂性大于非置换组。     

Isolated Resurfacing of the Previously Unresurfaced Patella Total Knee Arthroplasty

Postoperative anterior knee pain can be challenging after primary total knee arthroplasty. Isolated patellar resurfacing may provide symptomatic improvement in those patients with an unresurfaced patella. Seventeen isolated patellar resurfacing procedures were performed. Patient outcomes were evaluated using the Knee Society clinical and roentgenographic evaluation systems. Continued symptomatology and overall patient satisfaction were also analyzed. No revisions have been necessary at 47 months of follow-up. Overall, Knee Society knee scores and knee function scores significantly improved. Eight patients (53%) are asymptomatic and were satisfied with the procedure, whereas 7 patients (47%) continue to have anterior knee pain and are unsatisfied. Isolated patellar resurfacing for anterior knee pain in total knee arthroplasty with an unresurfaced patella has a low morbidity and revision rate but may not provide patients with predictable symptomatic improvement.