Strong evidence supports no difference in pain or function with or without patellar resurfacing in total knee arthroplasty.

Rationale
Strong evidence from high quality studies show very similar outcomes and complications with both patella resurfacing and no resurfacing. Unresurfaced categories often included a variety of limited debridements or releases such as circumferential patella osteophyte debridement or electrocautery. A meta-analysis showed that only reoperation rate (all reoperations, although a significant number were patella-related) was statistically increased in knees without patella resurfacing. This was only significant when enough reoperation data was aggregated to include reoperation after five years.
 
The high quality KAT trial (Breeman 2011 and Murray 2014) favors resurfacing for reasons of decreased reoperation. Four moderate quality studies also favored resurfacing for different reasons. Waters 2003 demonstrated higher anterior knee pain following total knee arthroplasty without resurfacing. Wood 2002 showed higher incidence of anterior knee pain in the knees that had not been resurfaced. One moderate quality study (Barrack 2001) showed anterior knee pain was same for overall KSS, and pain and function subscores, but reoperation significantly more common without resurfacing. Schroeder-Boersch 1998 showed better task knee function scores with resurfacing. Newman 2000 showed increased need for secondary surgery in the unresurfaced group. Partio 1995 showed decreased anterior knee pain in the resurfaced knees.
 
On the other hand, two high quality study (Bourne 1995) showed improved total Knee Society Scores (KSS) and KSS function scores in patients without patellar resurfacing. Liu 2012 chose to reshape the patella (osteophyte debridement) and found no difference in total KSS and in pain and function subgroups, arguing to keep patella bone stock. Campbell 2006 was unable to recommend resurfacing because of no significant differences in outcomes or complications. The KAT trial (Breeman 2011 and Murray 2014) found no statistically significant differences in EQ-5D score, SF-12 physical component scores and SF12 mental component scores.
 
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  2. Bourne,R.B., Rorabeck,C.H., Vaz,M., Kramer,J., Hardie,R., Robertson,D. Resurfacing versus not resurfacing the patella during total knee replacement. Clin Orthop Relat Res. 1995/12; 321: 156-161
  3. Breeman,S., Campbell,M., Dakin,H., Fiddian,N., Fitzpatrick,R., Grant,A., Gray,A., Johnston,L., Maclennan,G., Morris,R., Murray,D. Patellar resurfacing in total knee replacement: five-year clinical and economic results of a large randomized controlled trial. J Bone Joint Surg Am 2011/8/17; 16: 1473-1481
  4. Breeman,S., Campbell,M., Dakin,H., Fiddian,N., Fitzpatrick,R., Grant,A., Gray,A., Johnston,L., Maclennan,G., Morris,R., Murray,D. Patellar resurfacing in total knee replacement: five-year clinical and economic results of a large randomized controlled trial. J Bone Joint Surg Am 2011/8/17; 16: 1473-1481
  5. Campbell,D.G., Duncan,W.W., Ashworth,M., Mintz,A., Stirling,J., Wakefield,L., Stevenson,T.M. Patellar resurfacing in total knee replacement: a ten-year randomised prospective trial. J Bone Joint Surg Br 2006/6; 6: 734-739
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  7. Murray,D.W., MacLennan,G.S., Breeman,S., Dakin,H.A., Johnston,L., Campbell,M.K., Gray,A.M., Fiddian,N., Fitzpatrick,R., Morris,R.W., Grant,A.M. A randomised controlled trial of the clinical effectiveness and cost-effectiveness of different knee prostheses: the Knee Arthroplasty Trial (KAT). Health Technol Assess 2014/3; 19: 1-viii
  8. Newman,John H., Ackroyd,Christopher E., Shah,Nilen A., Karachalios,Theo Should the patella be resurfaced during total knee replacement?. The Knee 2000/1/1; 1: 17-23
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