Patellar Resurfacing Compared with Nonresurfacing in Total Knee Arthroplasty :A Concise Follow-up of a Randomized Trial J Bone Joint Surg Am,2009 Nov Presented by R4 李偉群 Tutor: 翁怡然 醫師

Indications for patella resurfacing Obesity Obesity Preoperative anterior pain in the knee Preoperative anterior pain in the knee moderate or severe chondromalacia moderate or severe chondromalacia patellar tilt or deformity patellar tilt or deformity OKU4 Without resurfacing will somewhat increase risk anterior knee pain but decrease serious patellar complication. (loosening and fracture) Without resurfacing will somewhat increase risk anterior knee pain but decrease serious patellar complication. (loosening and fracture) OKU8

Indications for patellar resurfacing Reoperation for anterior knee pain in unresurfacing group:10% (resurfacing:2%) Reoperation for anterior knee pain in unresurfacing group:10% (resurfacing:2%) Pain relief is not a predictor for resurfacing. Pain relief is not a predictor for resurfacing. Well tracking extensor mechanism,minimal patellar arthritis and patellar friendly femoral component  not resurfacing Well tracking extensor mechanism,minimal patellar arthritis and patellar friendly femoral component  not resurfacing OKU9

Resurfacing of patella: complication Postoperative anterior pain in the knee Postoperative anterior pain in the knee Subluxation, dislocation Subluxation, dislocation Osteonecrosis Osteonecrosis Patellar fracture Patellar fracture Patellar clunk Patellar clunk ranged from 4 % to 50 % ranged from 4 % to 50 % JBJS-A,1997

January 1992 and December 1993, 86 patients/118knees Inclusion criteria: degenerative osteoarthrosis Exclusion criteria: 1.Previous tibial osteotomy or operation involving the extensor mechanism 2.History of septic osteoarthrosis or osteomyelitis 3.Severe medical disability that limited the ability to walk 4.Disabling disease involving other joints of the lower extremities 5.Inflammatory arthropathy 6.Severe deformity (varus angulation, valgus angulation, or flexion contracture of more than 15 degrees) flexion contracture of more than 15 degrees)

86 patients/118 knees Patella resurface 58 knees Non-resurface,patelloplasty 60 knees F/U 30 months Miller-Galante-II, Zimmer,CR Patella- all PE

F/U 30 months - Clinical result The Knee Society score : Pain (P=0.56),Function (p=0.77) The Knee Society score : Pain (P=0.56),Function (p=0.77) Patient-satisfaction questionnaire Patient-satisfaction questionnaire Specific questions regarding patellofemoral symptoms and function. (P>0.64) Specific questions regarding patellofemoral symptoms and function. (P>0.64) Obesity (P>0.1) Obesity (P>0.1) Resurface(n=58)Non-resurface(n=60) Post –op anterior knee pain 4 6 (all revision and 5 still feel pain but decreased )

Resurface(n=58)Non-resurface(n=60) P valus Op time 128mins 115 mins 0.04 Lateral retinacular release 31%18%>0.1 Patellar thickness >0.1 Chondromalacia (Grade III+IV) 63%60%>0.1 post-op patella tilt lessmoreP<0.01 F/U 30 months -Operative data Chondromalacia Patellae and post-op pain,P=0.35 Chondromalacia Patellae and post-op pain,P=0.35

Chondromalacia ～ Outerbridge, 1961 Grade I Light brown-yellow discoloration, softening, no fragmentation or fissuring. II II Fragmentation and fissuring in an area of 1.3 cm or less. The size of the lesion was estimated by scanning the patella surface with the lens close to the cartilage. III III Fragmentation and fissuring in an area of more than 1.3 cm IV IV Erosion of the articular cartilage down to the subchondral bone.

F/U 30 months- conclusion Obesity, the grade of patellar chondromalacia, and preoperative anterior pain in the knee Obesity, the grade of patellar chondromalacia, and preoperative anterior pain in the knee – Not resurfacing indicator – Not resurfacing indicator Prospective,Randomized, Double-Blind Study Prospective,Randomized, Double-Blind Study Preliminary study Preliminary study No intermediate-term or long – term result No intermediate-term or long – term result

86 patients/118 knees Patella resurface 58 knees Non-resurface,patelloplasty 60 knees F/U 30 months Patella resurface 38 knees Non-resurface, patelloplasty 40 knees F/U 10 years 1 loosening 1 ON  fracture 4 anterior knee pain 7 knees (12%) resurface : 6  2-4 yrs 1  5-7 yrs VAS 8  2.3 (post-revision)  7.4 (last F/U)

The Knee Society score The Knee Society score Patient-satisfaction questionnaire: Patient-satisfaction questionnaire: Resurfacing (94%) v.s. Nonresurfacing (98%) Resurfacing (94%) v.s. Nonresurfacing (98%) Specific questions regarding patellofemoral symptoms and function. Specific questions regarding patellofemoral symptoms and function.  no difference in two groups  no difference in two groups F/U 10 years - Clinical result

～ Clinical Sports Medicine, 3rd ed, knees (12%) resurface finally in Non-resurfacing group: 7 knees (12%) resurface finally in Non-resurfacing group: VAS: pre-op 4.5  8  2.3 (post-revision)  7.4 (last F/U) 4 anterior knee pain (8%) did not revise in Resurfacing group 4 anterior knee pain (8%) did not revise in Resurfacing group

CORR, knees, F/U 5 years 5° of combined tibial and femoral internal malrotation will increase anterior knee pain. But no tilt or subluxation in X-ray

Conclusion With the type of TKA used, similar results may be achieved with and without resurfacing of the patella. With the type of TKA used, similar results may be achieved with and without resurfacing of the patella. Resurface the patella only in inflammatory condition of the knee. Resurface the patella only in inflammatory condition of the knee.

Thanks!!

Patellar resurfacing - Late complication Osteonecrosis of the patella Osteonecrosis of the patella Aseptic loosening Aseptic loosening Patellar fragmentation Patellar fragmentation Periprosthetic fracture Periprosthetic fracture Failure of the extensor mechanism Failure of the extensor mechanism