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Dr.P.Gopinathan, MS;MNAMS;DNB
Assistant Professor
Department of Orthopaedics, Medical College, Calicut

            After more than 20 years of debate the decision whether to resurface the patella or not during primary Total Knee Arthroplasty (TKA) remains controversial. So the ideal treatment for patella in primary TKA remains unclear. Patellar complications during primary TKA have begun to emerge as a major cause of failure.

            Placement of patellar component is usually more difficult than placement of any other component in TKA. It is usually the first component to fail after TKA. There are no specialized jigs available to do the patellar cut, even in Computer Assisted Orthopaedic Surgery (CAOS), but several jigs are being perfected but even now a perfect jig is not available commercially. In 1980s, there were several reports of complications related to patellar resurfacing.

            Many randomized trials have provided inconclusive evidence regarding the fact that patellar should be resurfaced or not. There are reports that a resurfaced patella may also be symptomatic with anterior knee pain. I aimed to understand the current concept from literature regarding whether the patella should be resurfaced or not routinely during primary TKA. 

Arnold MP et al1 in their study concluded that using a blood supply preserving approach and a biomechanically adequate implant TKA without patellar replacement gives excellent long term results. They showed in a long term follow up study of TKA that the femoro-patellar joint is an important problem after TKA.

Barrack RL2 in his study was of the opinion that every study to date has suggested that kinematics are more abnormal when patella is resurfaced than when it is retained. He also concluded that the patello-femoral contact areas are higher and contact stresses are lower in the native patella compared with resurfaced patella after TKA. Virtually every clinical study of bilateral knee arthroplasty in which patella has been resurfaced and the other has not shown either equivalent results or a preference for the unresurfaced side. Laboratory and clinical data indicate that not resurfacing the patella is a viable if not a preferable option in most TKA patients.

Burnett RS et al3 concluded that the management of patella in TKA traditionally has been one of the three options: always resurface, never surface or selectively resurface the patella. They also concluded that anterior knee pain before and after TKA much not always be presumed to be secondary to patello-femoral resurfacing / non-resurfacing etiology and other factors may play a role in the dynamic development of anterior knee pain after TKA. The decision to resurface the patella in TKA remains controversial, and the results of long term randomized controlled trails will improve the understanding  of this complex issue in the future.

Churchill DL et al4 were of the opinion that increasing the femoral roll back in flexion is thought to reduce the patello-femoral contact load in total knee arthroplasty. Posterior cruciate ligament (PCL) substituting TKA produced greatest and the most reproducible roll back. Moving the tibial post posteriorly, further increase the roll back. Increased roll back correlated with reduced patellar load. Quadriceps loads were reduced by increasing the roll back but to a smaller degree. The roll back primarily affects patellar load rather than the quadriceps or efficiency. 

Feller JA et al5 concluded that stair climbing ability was significantly better in the patellar retention group. Although there were no complications related to patellar resurfacing, in the medium term follow up, they did not find any significant benefit from re-surfacing the patella during TKA for osteoarthritis, if it was not severely deformed.

Harwin SF et al6 opined that successful femoropatellar resurfacing (PFR) can be accomplished with minimal complications if the following technical considerations are met: 5-7 degrees of valgus alignment; medial placement of patellar component, taking care not to increase either the AP diameter of the knee or the thickness of the patella; avoiding internal rotation either in the tibia or in the femor and proper soft tissue balance. If anything goes wrong, patello-femoral complication is a usual outcome.

Holt GE et al7 in their study made a final conclusion that patello-femoral complications the greatest argument against resurfacing of the patella can be diminished with improved surgical techniques and better implant designs.

Kelly MA8 was of the opinion that the diagnosis and treatment of the more-frequent complications should be studied in detail. Although this complications may be successfully treated, most may be largely avoided with proper surgical technique and prosthetic component design.

Levitsky KA et al9 inferred that in patients meeting the selection criteria, TKA without resurfacing the patella provided satisfactory long term results and a high degree of patient satisfaction with an absence of mechanical complications and no reoperations at an average of 7  years of follow up evaluation.

Matsuda S et al10 opined that design features of the patello-femoral portion of TKA component are important factors that affect contact stresses in the patellofemoral joint. These features will likely affect the clinical results of TKA with an unresurfaced patella.

Ogon M et al11 concluded that Patellar complications were more often found in the resurfaced group than in the group without resurfacing. The results indicate overall no advantage of patella resurfacing compared with patella retention in the long run.

Poll FE et al12  using temporal-spatial parameters and kinematic and kinetic variables at the knee joint were tested for significance using the repeated measures analysis of variance (ANOVA). There were no significant differences in the biomechanics of walking, stair climbing or chair rising between patients after TKA with and without a resurfaced patella. So they did not find any advantage of resurfacing the patella.

Reuben JD et al13 inferred that TKA system should include instrumentation that allows precise restoration of overall patellar thickness while maintaining a bony patellar thickness of at least 15mm will only produce better results. They also concluded that patellar complications following total knee arthroplasty have begun to emerge as a major cause of failure.

Stiehl JB et al14 were of the opinion that kinematic abnormalities of the prosthetic patellofemoral joint may reduce the effective extensor movement after TKA.

            Majority of the current articles are favouring the non-resurfaced patella in terms of anterior-knee pain, functional outcome and patient satisfaction. Newer designs are compatible with natural patella and there is a perfect remodeling of the natural patella in the non-resurfaced group.

            So majority of the future TKA may be of patellar non-surfaced type provided better prosthetic designs are available.


Arnold MP, Friedrich NF, Widmer H, Muller W. Patellar Substitution in total knee prosthesis is it important?, Orthopade, 1998; 27(9) 637-41.

Barrack RL. Orthopaedic Crossfire All patellae should be resurfaced during primary total knee arthroplasty : in opposition. J. Arthroplasty. 2003;  (3 Suppl 1) 35-8.

Burnett RS, Bourne RB. Indications for patellar resurfacing in total knee arthroplasty. Instr Course Lect. 2004; 53: 167-86.

Churchill DL, Incavo SJ, Johnson CC, Beynnon BD. The Influence of femoral rollback on patellofemoral contact loads in total knee arthroplasty.  J Arthroplasty. 2001; Oct.16(7): 909-18.

Feller JA, Bartlett RJ, Lang DM. Patellar resurfacing versus retention in total knee arthroplasty. JBJS Br. 1996; 78(2): 226-8.

Harwin SF, Stein AJ, Stern RE. Patellofemoral resurfacing at total knee arthroplasty. Contemp Orthop. 1994; 29(4): 265-71.

Holt GE, Dennis DA. The role of patellar resurfacing in total knee arthroplasty. Clin. Orthop. 2003; 416: 76-83.

Kelly MA. Patellofemoral complications following total knee arthroplasty. Instr Course Lect. 2001; 50: 403-7.

Levitsky KA, Harris WJ, McManus J, Scott RD. Total knee arthroplasty without patellar resurfacing. Clinical outcomes and long-term follow-up evaluation. Clin. Orthop. 1993; 286: 116-21.

Matsuda S, Ishinishi T, Whiteside LA. Contact stresses with an unresurfaced patella in total knee arthroplasty : the effect of femoral component design. Orthopedics, 2000; 23(3): 213-8.

Ogon M, Hartig F, Bach C, Nogler M, Steingruber I, Biedermann R. Patella resurfacing : no benefit for the long-term outcome of total knee arthroplasty. A 10 to 16.3 year follow up. Arch Orthop Trauma Surg. 2002; 122(4): 229-34.

Pollo FE, Jackson RW, Koeter S, Ansari S, Motley GS, Rathjen KW. Walking, chair rising and stair climbing after total knee arthroplasty: patellar resurfacing versus non-resurfacing. Am J Knee Surg. 2000 Spring 13(2): 103-8. Disussion 108-9.

Reuben JD, McDonald CL, Woodard PL, Hennington LJ. Effect of patella thickness on patella strain following total knee arthroplasty. Arthroplasty. 1991;  6(3): 251-8.

Stiehl JB, Komistek RD, Dennis DA, Keblish PA. Kinematics of the patellofemoral joint in total knee arthroplasty. J Arthroplasty. 2001; 16(6): 706-14.




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