Management of Infection and Periprosthetic Fracture in TKR 蔡旻虔, 徐郭堯 膝關節重建與運動醫學科 長庚林口醫學中心

Management of Infection After Knee Arthroplasty

Infection after TKR: 0.5% ~ 2% 無論診斷與治療,都是一項很大的挑戰 TKA術後有任何的pain或不適,都要先想是不是有infection的問題

infection host bacteria path, wound

Pathogens present to implant Surgical contamination Hematogenous spread Recurrent infection Direct inoculation or contiguous spread Schmalzried,et al. Clin Orthop.1992

Pathogen Most popular pathogen of biomaterial – associated infection - Staphylococcus species aerobic Gram-negative bacteria - 10% ~ 20% anaerobic bacteria - 10%

Pathogen Early-onset infection (< 3 months) - virulent pathogen - S aureus, G(-) bacilli Delay-onset infection (3 ~ 24 months) - less virulent - coagulase-nagative staphylocicci Late-onset infection (> 24 months) - S aureus, CoNS, E Coli …….

Biofilm Microorganisms encapsulated within a self-developed polymeric matrix and adherent to a biomaterial surface Pathogen more resists to - antibiotics - phagocyte Debridement

Host risk factor for periprosthetic infection DM Obesity (BMI > 30) Old age (> 80 y/o) ASA > 2 Smoking Hepatic insufficiency Renal insufficiency …...

Classification of deep periprosthetic infection Type Presentation Definition I Positive Intra-op Culture > 2 positive intra-op culture II Acute Post-op infection Acute infection within 4 weeks after the operation III Acute hematogeneous infection Acute onset of infection at a previously well-functioning joint replacement IV Late chronic infection Chronic infection, Infection presents > 1 month

Diagnosis Symptom and sign - fever, chillness - sever joint pain, especially rest pain - local heat and swelling effusion - pus discharge, discharge sinus

Diagnosis Radiographic study - nonspecific change implant loose, osteolysis, … - to rule out other conditions

Diagnosis Radionuclide image - Bone scan - Gallium scan - WBC scan - PET scan

Diagnosis Hematologic test - WBC - ESR - CRP Joint aspiration Frozen section - < 5 PMN in each HPF

Treatment Treatment options - antibiotics use - debridement - resection arthroplasty - exchange arthroplasty - stage revision arthroplasty

Treatment Considerations - type and duration of symptoms - detail postoperative course - local condition - host condition - implant condition

Debridement - Early infection (type II) or infection with symptoms< 1 month (type III) - Stable prosthesis - No discharging sinus

Two-stage revision For delay or late onset infection Popular use High successful rate

Two-stage revision Removal of implants and debridement and joint stabilized with anti-loaded cement spacer IV anti use 4 ~ 6 weeks f/u CRP and clinical S/S Reimplamtation implants

Optimal timing for reimplantation 6 ~ 12 weeks after 1st stage op Sequential CRP f/u Follow up local condition Delay aspiration 2~4 weeks after DC anti Intra-op frozen section

Prevention Host - Identified the risk factor - Careful screen occult or minor infections prior to TKR Operation field Prophylaxis antibiotics - cefazlion 1g IV less than 80 kg, 2g IV more than 80 kg - repeat dose in 2 ~ 5 hr interval

TKA periprosthetic fracture

Fracture in TKA A very challenging problem to orphopaedic doctors

What’s the problem we face Old age patient High Anesthesia and OP risk Poor bone stalk Difficult to fixation Implant stability Knee function

Incidence of femoral fracture after TKA After Primary TKR 0.3-2.5% Merkel KD, Johnson EW. J Bone Joint Surg 1986;68:29–43 After revision TKR 1.6%-38% Kang-Il Kim, MD; Kenneth A. Egol, MD. CORR 2006; 446: 167–175

Femoral supracondylar fracture after TKA Severe osteoporosis Usually D/3 of femur Within 15cm of joint line Often cause by low energy trauma

Risk factors Patient factors Local factors Rheumatoid arthritis Osteolysis Osteoporosis Anterior femoral notching Steroid use Stress risers Neurologic disorders Loosening Smoking Stiffness knee Immunosuppression Female sex Frequent falls

Classification Lewis & Rorabeck, 1998

Rorabeck Classification Type II

Rorabeck Classification Type III

Treatment Goal Stable fracture site Restore alignment Preserve bone stock Early range of motion Restore knee function

Pre-OP planning Type of fracture Degree of displacement Type of TKA Presence of infection or loosening of the prosthesis patient factors pre-fracture morbidity, mobility and bone quality.

Treatment methods Conservative treatment Operative management Open reduction and internal fixation Revision TKR Custom made prosthesis

Plate fixation Fixed angle Plate Conventional DCP

Plate fixation Advantage Disadvantage good visualization of fracture site Less technique demand Disadvantage Another approach Soft tissue compromise Difficult reduction Unable to change linear Plate failure in poor bone stalk

Locking plate system

Locking plate system Advantage Disadvantage Uni-cortex purchase Prevent plate-bone compression Anatomic contour Disadvantage Limited screw direction Unable to bending

Is single plate enough??

Is single plate enough??

After 3 months…

Double plate fixation

For plating fixation Single conventional plating is not enough Double plating or combined with locking plate is more stable

Retrograde Nail

Retrograde Nail Advantage Disadvantage Less invasive (same incision) Easy apply and reduction Possible change linear Disadvantage Limited by prosthesis design CR vs PS type Distal fixation

Retrograde nail + Plating Single approach Easy apply + reduction Very stable fixation Axial stability Rotation stability May change liner if necessary

Revision TKR Indication Implant choice Severe comminuted fracture Fracture associated implant loosening Implant choice Log stem prosthesis Allograft-prosthesis complex (APC) Tumor prosthesis or custom made

Key- points Pre-Op planning Maintain alignment Stable fixation Retrograde nail combined plating Chang insert if necessary Double plating /locking plate Adequate bone grafting

Thanks for attention!!