Does malrotation of components correlate with patient dissatisfaction following secondary patellar resurfacing?
Introduction
Over 75,000 primary total knee arthroplasty (TKA) were carried out in England and Wales in 2010 [1]. Whether or not the patella should be resurfaced during primary TKA continues to be an issue of debate. Early TKA implant designs were associated with significant complaints (20%–40%) of anterior knee pain [2]. This led to the development of patellar resurfacing components. However subsequent femoral component design was more compatible with both natural and resurfaced patellae and there remains a controversy as to whether the patella should be resurfaced or not. Since then, some authors have suggested selective patellar resurfacing [3], [4].
There is evidence that not resurfacing the patella is likely to be the most common reason for reoperation following primary TKA [5], [6], largely due to persistent post-operative anterior knee pain [7]. Conversely, resurfacing of the patella is not without its own problem such as fracture, avascular necrosis and loosening [8].
The decision making process as to whether or not to resurface the patella during TKA therefore varies according to location, surgical and patient related factors. Some surgeons resurface all patellae at the time of primary TKA, others will never routinely resurface. Numerous centres and surgeons attempt to use specific criteria (preoperative or intraoperative) for choosing those patients suitable for patellar resurfacing. Several authors have attempted to set out criteria to aid preoperative decision making in relation to patellar resurfacing as a part of TKA [5], [9]. Examples of criteria used for patient selection for resurfacing include a history of anterior knee pain or other symptoms of patellofemoral involvement in the disease process, radiological evidence of patellofemoral involvement, clinical evidence of involvement during surgery, loss of patella height/thickness and patella baja/alta. Contraindications to patellar resurfacing include soft/osteoporotic bone, small patellae, extreme wear/thinning of the patella and, in some cases, young patients with high demand [5], [9]. Thus far, a method for accurately predicting which patients can avoid patellar resurfacing has not been agreed [10].
There are few studies in the literature which have reported the outcomes of secondary patellar resurfacing for anterior knee pain [11], [12], [13], [14]. The patient satisfaction outcome from these studies varies from 40% to 90%. The secondary patellar resurfacing procedure can lead to further complications such as fracture and patellar maltracking and there is some evidence that late resurfacing may hasten revision [13].
It has long been suspected that malrotation of the femoral and tibial components at the time of primary TKA may lead to subsequent patellofemoral problems [15]. Berger et al. [15] reported on the outcome of 30 patients undergoing revision surgery for patellofemoral complications. Minor degrees of combined internal rotation were associated with patella subluxation whereas major amounts of internal rotation were associated with patella dislocations and prosthesis failure. None of the studies on secondary patellar resurfacing have identified the causes of the unsatisfactory outcomes.
The aim of our study was to assess the outcome in a retrospective series of patients that underwent secondary patellar resurfacing for persistent anterior knee pain following previous TKA without primary patellar resurfacing. We observed the common factors that these patients possessed, paying particular attention to component rotation, in order to identify predictive outcomes likely to lead to poor results following secondary patellar resurfacing. In particular, we analysed whether those patients that underwent secondary patellar resurfacing had the femoral and/or tibial components implanted in a malrotated position during the primary procedure. In addition, any observed malrotation was correlated with clinical outcome of the secondary procedure.
Section snippets
Methods
We identified all patients that underwent secondary patellar resurfacing for persistent anterior knee pain following previous primary TKA within an 8½ year period at a single, large elective orthopaedic department. All of these patients had been assessed for persistent anterior knee pain and infection and aseptic loosening had been excluded as possible causes. They were deemed suitable for secondary patellar resurfacing based on clinical and radiographic findings.
The patients were reviewed in a
Materials
Within our department approximately 5000 primary total knee arthroplasties were carried out without patellar resurfacing between January 2003 and June 2011. During this period, 25 patients (27 knees) underwent secondary patellar resurfacing following previous TKA. Of these patients, three declined participation in the study and one was not contactable.
Twenty-one patients (23 knees) were clinically reviewed. Mean time to follow up from the secondary surgery to the clinical review was 33.9 months.
Results
The patients included 12 males (one with bilateral involvement) and nine females (one with bilateral involvement). Fifteen knees were left-sided and eight were right.
The mean patient age at primary surgery was 66 years (range 51–80 years) and the mean patient age at patellar resurfacing surgery was 69 years (range 55–84 years), with a mean time between primary and secondary surgery being 42 months (range 14–100 months).
At clinical review, the mean maximal knee extension was measured at 1° (range
Discussion
This series demonstrated a significant correlation between unsatisfactory outcome in patients requiring secondary patellar resurfacing for anterior knee pain and primary femoral component internal rotation. Patients undergoing secondary patellar resurfacing for anterior knee pain following TKA are more likely to be dissatisfied with the outcomes of surgery if the femoral component is internally rotated more than 3°.
Satisfaction rates following total knee arthroplasty vary between 85 and 95% [19]
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[Translated article] Study of femoral component malrotation as a cause of pain after total knee arthroplasty
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2023, KneeCitation Excerpt :The most important finding of this study was that the characterisation of kinematics and kinetics in both knee joint compartments during a squat motion for the investigated CR-TKR mainly depends on the anterior-posterior and medio-lateral positioning of the femoral component and varying tibial insert thickness. Despite the high success rates in the current practice of TKR surgery and the implant design used (P.F.C. Sigma CR) [23,26,69], one major clinical complication after TKR remains anterior knee pain [5,19,25]. For instance, Groes et al. [24] reported that patients still have pain during the squat movement after TKR.