A Clinical Study on the Delayed Union of the Fractures in the Proximal Tibial Metaphysis

Lee, C J; Kang, J W; Yang, Y S; Ahn, B M; Lee, Y M

Abstract

We had frustrating experiences of a delayed union in dealing with the proximal tibial fractures which prompted us to analyse all our cases of tibial fractures in the proximal metaphyseal area. The proportion of tibial fractures in the proximal metaphyseal region and its exact incidence of delayed union were studied and each probable cause was sought. An experiment was performed upon an amputated specimen of a human lower limb to observe the influence of Quadriceps pulling on the proximal osteotomized fragment of upper tibia. The results were as follows: 1. Of 206 cases of tibial shaft fracture, 30 cases (14.5%) were proximal tibial metaphyseal fractures. 2. Of 30 proximal tibial metaphyseal fractures, 10 cases (33.3%) were delayed union. 3. The mean age was 39.9 years, the range being from 16 to 70. 4. Of 34 patients, the sex ratio between male and female was 27:7. 5. a) Of 34 patients, fracture through the tibial tubercle were 16 cases (47%) and fracture below the tibial tubercle were 18 cases (53%). b) Of 14 delayed union cases, fractures through the tibial tubercle were 14 cases (28.8%) and fractures below the tibial tubercle were 10 cases (71.2%). 6. Of 14 cases, open fractures was 7 cases (50%) and closed fracture was 7 cases (50%). 7. 25 cases out of 34 were comminuted fractures. 8. All 14 cases of delayed union were combined with the fibular fracture. 9. Factors influencing union rate were: a) combined fibular fracture, b) level of fracture, and c) angle of knee during long leg cast immobilization. 10. There was considerable mobility and instability at the osteotomy site causing definite shearing stresses and these might adversely affect the primary fracture healing mechanism of the cancellous metaphyseal bone which would be the prime healing mechanism in this area.