Does patella resurfacing really matter? Pain and function in 972 patients after primary total knee arthroplasty.
OBJECTIVE
Resurfacing of the patella during primary total knee arthroplasty (TKA) is often recommended based on higher revision rates in non-resurfaced knees. As many of these revisions are insertions of a patella component due to pain, and since only patients with a non-resurfaced patella have the option of secondary resurfacing, we do not really know whether these patients have more pain and poorer function. The main purpose of the present paper was therefore to assess pain and function at least 2 years after surgery for unrevised primary non-resurfaced and resurfaced TKA, and secondary among prosthesis brands.


METHODS
Information needed to calculate subscales from the knee injury and osteoarthritis outcome score (KOOS) was collected in a questionnaire given to 972 osteoarthritis patients with intact primary TKAs that had been reported to the Norwegian Arthroplasty Register. Pain and satisfaction on visual analog scales and improvement in EQ-5D index score DeltaEQ-5D) were also used as outcomes. Outcomes were measured on a scale from 0 to 100 units (worst to best). To estimate differences in mean scores, we used multiple linear regression with adjustment for possible confounders.


RESULTS
We did not observe any differences between resurfacing and non-resurfacing in any outcome, with estimated differences of <or= 1.4 units and p-values of > 0.4. There was, however, a tendency of better results for the NexGen implant as compared to the reference brand AGC for symptoms (difference = 4.9, p = 0.05), pain (VAS) (difference = 8.3, p = 0.004), and satisfaction (VAS) (difference = 7.9, p = 0.02). However, none of these differences reached the stated level of minimal perceptible clinical difference.


CONCLUSIONS
Resurfacing of the patella has no clinical effect on pain and function after TKA. Differences between the brands investigated were small and they were assumed to be of minor importance.
The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Norway. stein.lygre@helse-bergen.no
Stein Håkon Låstad
SH
Lygre
Birgitte
B
Espehaug
Leif Ivar
LI
Havelin
Stein Emil
SE
Vollset
Ove
O
Furnes
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D007720:Knee Prosthesis / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009664:Norway; D010146:Pain / Q000209:etiology; D010147:Pain Measurement; D010329:Patella; D017060:Patient Satisfaction; D011474:Prosthesis Design; D012042:Registries; D011795:Surveys and Questionnaires; D016896:Treatment Outcome