Secondary patella resurfacing in painful non-resurfaced total knee arthroplasties : A study of survival and clinical outcome from the Norwegian Arthroplasty Register (1994-2011).
OBJECTIVE
In Norway, 19 % of revisions of non-resurfaced total knee arthroplasties done for knee pain between 1994 and 2011 were Secondary Patella Resurfacing (SPR). It is, however, unclear whether SPR actually resolves the pain. The aim was to investigate prostheses survival and clinical outcomes following SPR.


METHODS
A total of 308 knees (301 patients) with SPR were used to assess implant survival, and a sub-cohort (n = 114 out of 301 patients) with Patient Reported Outcome Measures (PROMs) data were used to assess the clinical outcomes. The EuroQol (EQ-5D), the Knee Injury and Osteoarthritis Outcome Score, and Visual Analogue Scales on satisfaction and pain were used to collect PROM data. Outcomes were analysed by Kaplan-Meier, Cox regression, and multiple linear regression.


RESULTS
The five- and ten-year Kaplan-Meier survival percentages were 91 % and 87 %, respectively. Overall, 35 knees were re-revised at a median follow-up of eight years and pain alone (10 knees) was the main cause of re-revision. Younger patients (<60 years) had nearly nine times higher risk of re-revision compared to older patients (>70 years) (RR = 8.6; p < 0.001). Mean EQ-5D index score had improved from 0.41 (SD 0.21) preoperative to 0.56 (SD 0.25) postoperative following SPR. A total of 63 % of patients with PROM data were satisfied with the outcomes of SPR.


CONCLUSIONS
The long-term prostheses survival following SPR was satisfactory, although not as good as for primary knee replacement. Patients' health related quality of life improved significantly following SPR. Still, more than a third of patients with PROMs data were dissatisfied with the outcomes of the SPR procedure.
The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway. tesfaye.hordofa.leta@helse-bergen.no.|Department of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway. tesfaye.hordofa.leta@helse-bergen.no.
Tesfaye H
TH
Leta
Department of Occupational Medicine, Haukeland University Hospital, Bergen, Norway.
Stein Håkon L
SH
Lygre
The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway.
Arne
A
Skredderstuen
The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway.
Geir
G
Hallan
The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway.
Jan-Erik
JE
Gjertsen
Department of Research and Development, Haukeland University Hospital, Bergen, Norway.|Department of Global Public Health and Primary Care, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway.
Berit
B
Rokne
The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway.
Ove
O
Furnes
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009664:Norway; D010146:Pain / Q000209:etiology / Q000601:surgery; D010147:Pain Measurement; D010329:Patella / Q000601:surgery*; D011475:Prosthesis Failure; D011788:Quality of Life; D012042:Registries; D012086:Reoperation; D016019:Survival Analysis; D016896:Treatment Outcome
Functional outcome; Health-related quality of life; Pain; Prostheses survival; Satisfaction; Secondary patella resurfacing