Post Fracture Arthritis of the Acetabulum THA in the treatment of post-traumatic arthritis of acetabulum is challenging --extensive scarring --retained hardware --heterotopic bone --residual deformity of acetabulum ~Rockwood p.718

Post Fracture Arthritis of the Acetabulum Berry and Halasy –33 pt’s acetabulum post-traumatic arthritis,uncemented acetabular component –2 shells revision for cup loosening;2 for osteolysis –15 hips of 14 pt’s; >10 yrs F/U; 8 no pain,6 mild pain,13 walked without support Weber et al –66 pt’s, THA for postraumatic OA,10 yrs F/U –44 cemented cups, 9 revision for loosening –22 uncemented cups, none revision,no loosening ~Rockwood p.720

Acute Fracture Mears and Velyvis –THA for acetabulum acute fracture –Ave. >8 yrs F/U, age 69 y/o, –45/57 (79%) pt’s good to excellent HHS –Cups subsided 2mm vertically, 3mm medially,6wks post-op Mears –Post. wall fracture with impaction involving 50% of acetabulum  structural autograft from femoral head  anchored into defect with screws  reaming  cup oversized by 2mm –Transverse fractures: braided cable passed in figure of eight fashion in the inner surface of the quadrilateral plate ~Rockwood p.720

Acute Fracture Moushine et al –18 elderly pt’s, early F/U –Acute THA + cable fixation, (single Dall-Miles cable,figure of eight) –Tensioning provided necessary compression and permit implatation of an uncemented cup –12 excellent result,6 good result (36mo) –14 cups migrated (Ave. 2.3mm),all fracture healed ~Rockwood p.720

Infected Fractures Infection following treatment of periprosthetic fracture of the femur has been reported as a complication in several series Primary treatment of a periprosthetic fracture that in infected is confied to case reports PROSTALAC(prosthesis of antibiotic loaded acrylic cement) in infected THA with proximal femoral bone loss –Long stem may useful in treating infected fractures ~Rockwood p.720

Infected Fractures Hartford and Goodman –3 cases of infected periprosthetic fracture (Locked IM nail as interim or salvage) –2 cases successfully revision to THA; 1 fractured healed and pt satisfied Schwab et al –One case, infected periprosthetic fracture of femur with IM device +antibiotics loaded cement around nail –Infection free 5 years after revision to hybrid THA ~Rockwood p.720

Complications

Nonunion of Periprosthetic Fractures Majority of periprosthetic fracture heal; small percentage go on nonunion Crockarell et al –9/224 (4%) nonunion, periprosthetic fx –23/807 nonunion,52% complication rate, treat 16 pt’s(retaining the proximal femur),10 healed with the first procedure Springer et al –4 nonunion(118 revision for Vancouver type B) –No nonunion among the 30 hips with fully porous coated prosthesis ~Rockwood p.720

Nonunion of Periprosthetic Fractures Attention to basic principles in important in achieving union 6/16 (Vancouver B1, B3 fractures treated with Dall-Miles plates),nonunion or fracture through the plate The authors advocated –If stem unstable: plates+ long-stem revision prosthesis –If stem well-fixed: cortical strut grafts + plates ~Rockwood p.720

PERIPROSTHETIC FRACTURES ABUT TOTAL KNEES

Principles of Management Epidemiology Sharkey et al –1997~2000,retrospective,212 knee revisions –2.8% of periprosthetic fractures(Table 22-8) Berry –Mayo Clinic Joint Registry,nearly 30 yrs –3% for primary + revision knees (Table 22-9) The 2000 National Hospital Discharge Survey –Revision TKA: 12,000 (1990)  28,000 (2000) –Estimate 784 periprosthetic fractures per year, at a const of nearly $20 million ($25,000/per revision) ~Rockwood p.720

Table 22-8 Overall Reasons for Revision Surgery Percentage Polyethylene wear25.0 Loosening24.1 Instability21.2 Infection17.5 Arthrofibrosis14.6 Malalignment or malpositioned11.8 Extensor mehanism deficiency6.6 Avascular necrosis patella4.2 Periprosthetic fracture2.8 Isolated patellar resurfacing0.9 From Sharkey PF, Hozack WJ, Rothman RH, et al. Insall Award paper. Why are total knee arthroplasties failing today? Clin Orthop 2002;404:7-13.

Table 22-9 Fracture Incidence About Total Knee Arthroplasties from the Mayo Clinic Registry Total No. of cases Femur % Tibia %Patella %Total % Intraoperative primary 16,90623(0.1)13(0.67)0(0)36(0.2) Intraoperative revision 2,90424(0.8)25(0.8)8(0.2)57(1.9) Postoperative primary 16,906161(0.9)75(0.4)117(0.7)353(2.1) Postoperative revision 2,90448(1.6)26(0.9)53(1.8)127(4.4) Total19,810*256(1.3)139(0.7)178(0.9)573(2.8) *Total of all primary and all revision cases. From Berry DJ. Epidemiology: hip and knee. Orthop Clin North Am 1999;30(2): , with permission.

Etiology Systemic Factors Osteopenia –Major contributing factors to periprosthetic Fx in TKA –RA,esp. corticosteroid users, increased risk for Fx Petersen et al –29 pt’s, 1 year after TKA, measured bone mineral density (BMD) in various regions of distal femur –Significant bone loss(19%~44%) compared to the initial values –Decreased BMD in anterior distal femur  important determinant of periprosthetic Fx and later failure of the femoral component ~Rockwood p.720

Etiology Petersen et al –Significant stress shielding in anterior distal femur in TKA pt’ 2 yrs after surgery –Similar and progressive decreased in BMD below the tibia component in 25 pts at 3 years F/U Wang et al –48 female pt’s,TKA, decreased BMD in distal femur and pxoximal tibia –Alendronate for 6 months post-op,BMD significantly improved Might reduce periprosthetic Fx after TKA ~Rockwood p.720

Etiology Osteoporosis Stress fractures may develop in pt’s who were inactive for an long period and suddenly mobilized following TKA Sudden onset of pain about knee during rehabilitation Stress fracture of proximal femur –Rare, can be diagnostic challenge –Tenderness over groin within weeks of resuming full-weight bearing after surgery –Bone scan or X-rays may reveal femoral neck or subtrochanteric stress fx –Protected weight bearing and observation is usually successful ~Rockwood p.720