Delayed union of fractures of the shaft of the adult tibia: A clinical and experimental study.

Fractures of the adult tibial shaft are common and often result in considerable morbidity because a significant number exibit slow healing. The reasons for this are not known and, therefore, prevention is not possible. This has been investigated using clinical and experimental methods. One hundred closed adult tibial shaft fractures treated by closed methods were studied to determine the true delayed union rate and the clinical factors that may be of importance. In addition, an attempt was made to predict fractures at risk using serial biochemical measurements and scintigraphic examination using technecium 99m methylene diphosphonate. The patterns of soft tissue damage in tibial shaft fractures were investigated experimentally in rabbits. Healing of a simple osteotomy was studied after the exclusion of periosteum, medullary or both tissues respectively from the fracture site. Cortical arterial perfusion was studied after the isolation of periosteal, nutrient and epiphyseo-raetaphyseal circulations respectively using a diaphyseal segment model and barium sulphate perfusion techniques. The delayed union rate was 19% at 20 weeks and 15 more fractures united at 30 weeks with continued conservative treatment. Of the clinical factors investigated, only the severity of trauma appeared to play a part in delayed union. Serum creatinine phosphokinase levels rose after fracture and provided some indication of severity of trauma. Serum calcium and inorganic phosphate levels rose after fracture and then progressively fell over a 20 week period. Serum levels of osteocalcin and somatomedins did not fluctuate. Biochemical parameters were not useful in identifying fractures at risk of developing delayed union. Of all scintigraphic methods, only the A/C ratio of uptake over the fracture site relative to an adjacent site, with a cut off value of 2.0, clearly separated normal from delayed union. Simple osteotomies of the rabbit tibial diaphysis healed normally in the absence of medullary tissues but not in the absence of periosteum. Cortical arterial perfusion was observed in diaphyseal segments of the rabbit tibial diaphysis up to 2 weeks but not thereafter when entrusted to the nutrient circulation alone. When entrusted to the periosteal circulation alone, cortical perfusion could be observed immediately after death, but not thereafter until 2 weeks after the procedure had been performed. To the memory of my father, David Babajide Oni B.A Hon. (Lond.) CONTENTS page PREFACE i 1 INTRODUCTION 1.1 ADULT TIBIAL SHAFT FRACTURES 2 1.2 THE BLOOD SUPPLY OF THE SHAFT (DIAPHYSIS) OF THE TIBIA 1.21 THE 1.211 The 1.212 The 1.213 The 1.214 The 1.22 THE 1.221 The 1.222 The concept 1.223 The 1.224 The cortex 1.23 THE 10 10 12 12 13 14 15 19 21 22 OSSEOUS CIRCULATORY SYSTEMS 24 1.231 The classical vascular isolation techniques 25 1.232 The modern vascular isolation techniques 28 1.24 THE BLOOD SUPPLY TO HEALING FRACTURES 31 1.241 The concept of periosteal blood supply to healing fractures 32 1.242 The concept of medullary blood supply to healing fractures 33 1.243 Anatomical studies of the blood supply to healing fractures 34 1.244 Vascular isolation techniques in the study of the blood supply to healing fractures 36 1.3 FRACTURE HEALING 39 1.31 NORMAL HEALING 39 1.311 The haematoma concept of fracture repair 39 1.312 The periosteal concept of fracture repair 40 1.313 The competing blastemata concept of fracture repair 42 1.314 Sources of osteogenic cells for fracture repair 43 1.315 The stimulus for osteogenesis in normal fracture repair 45 1.32 DELAYED UNION AND NON UNION 47 1.321 Delayed union 48 1.322 Non union 49 1.323 Patho-radiological types of delayed and non union 50 1.33 CAUSES OF DELAYED UNION 50 1.331 Vascular damage as a cause of delayed union 52 1.332 Soft tissue damage as a cause of delayed union 56 1.333 Periosteal damage as a cause of delayed union 59 1.334 Bony damage as a cause of delayed union 63 1.4 PREVIOUS APPROACHES TO THE STUDY OF DELAYED UNION OF ADULT TIBIAL SHAFT FRACTURES 65 1.41 CLINICAL ESTIMATION OF SEVERITY OF FRACTURE 65 1.42 RADIOLOGICAL CLASSIFICATION OF FRACTURE 69 1.43 BONE-SEEKING RADIONUCLIDE UPTAKE AFTER FRACTURE 74 1.44 OSTEOMEDULLOGRAPHIC EVALUATION OF FRACTURE HEALING 80 1.5 SUMMARY AND PURPOSE OF STUDY 82 2 CLINICAL STUDIES 2.1 AN INVESTIGATION OF THE NATURAL HISTORY OF THE HEALING OF CLOSED ADULT TIBIAL SHAFT FRACTURES TREATED BY CLOSED METHODS 86 2.1