[Distal femoral periprosthetic fractures: classification and therapy].

PURPOSE OF THE STUDY: Periprosthetic fracture is one of the most serious complication of total knee arthroplasty. In our retrospective clinical study we designed our classification with rules for treatment of those fractures.

MATERIAL AND METHODS: During the last thirty years we treated 53 distal femoral periprosthetic fractures in our orthopaedic department. In our clinical study we reviewed our group of distal femoral periprosthetic fractures with on the basis of X-ray findings, the treatment method used and treatment outcomes.

RESULTS: According to our findings we divided distal femoral periprosthetic fractures into six groups: Type I Nondisplaced fractures, 5.7%; treatment failure rate, 33%. Type II a Fractures with lateral comminution (the most often type of fractures), 37.7%; treatment failure rate, 20%. Type II b Fractures with medial comminution, 7.5%; treatment failure rate, 60%. Type II c Fractures above TKA (the second most often type), 34%; treatment failure rate, 18%. Type II d Comminuted fractures, 5.7%; treatment failure rate, 18%. Type IIIFractures with loosening of TKA, 9.4%; treatment failure rate, 20%. For the treatment of fractures we used various methods according to the type of fracture: Plate osteosynthesis in 32 cases, with failure in seven. Three failures in IIa group due to incorrect osteosynthesis with condylar plate, treated by reosteosteosynthesis with same implant. One in IIb group treated primarily with cement plomb, after second failure treated with revision total knee arthroplasty. Two failures in IIc group, treated by reosteosynthesis with spongioplasty using the same implant. One failure in III group solved with revision TKA. Intramedullary nail in nine cases , with failure in two. One failure in IIb group treated by reosteosynthesis with condylar plate and cement plombage. One in IIc group due to infection, solved with extraction of material and second stage revision TKA. Conservative treatment in three cases,with failure in two. One in I group treated with condylar plate. One in IId group solved with revision TKA. Miniosteosynthesis in three cases, with failure in two.One failure in IIa group treated with condylar plate, one in IIb group treated with intramedullary nail and additional hydroxyapatite plombage. Revision total knee arthroplasty in five cases with no failure. Extraction of TKA, external fixation, and arthrodesis in 1 case with no failure.

DISCUSSION: The rules for treatment of distal femoral periprosthetic fractures are not definite yet. For fractures above TKA is recommended nail osteosynthesis; for fractures at the level of femoral component is preferable to use osteosynthetic material, condylar plate or LCP. Bone grafts, bone cement, and artificial bone are used to augment osteosynthesis in comminuted fractures. Fractures at the site of loosening are indicated for revision TKA.

CONCLUSIONS: According to our results: Type I: Conservative treatment possible. Osteosynthesis with condylar plate is recommended. Type IIa: Indication for condylar plate osteosynthesis. Type IIb: The most problematic group. Osteosynthesis with condylar plate with augmentation or condylar plate placed from medial side. Type IIc: Plate osteosynthesis possible, intramedullary nail is recommended. Type IId: Osteosynthesis with augmentation is possible in some cases; revision TKA is recommended. Type III: Indication for revision TKA.