Aus der Klinik und Poliklinik für kleine Haustiere des Fachbereichs Veterinärmedizin der Freien Universität Berlin Patellar luxation and concomitant cranial cruciate ligament rupture in small breed dogs Inaugural Dissertation zur Erlangung des Grades eines Doktors der Veterinärmedizin an der Freien Universität Berlin vorgelegt von Mario Candela Andrade Tierarzt aus Ceuta (Spanien) Berlin 2019 Journal-Nr.: 4132 Gedruckt mit Genehmigung des Fachbereichs Veterinärmedizin der Freien Universität Berlin Dekan: Univ.-Prof. Dr. Jürgen Zentek Erster Gutachter: Prof. Dr. Leo Brunnberg Zweiter Gutachter: Univ.-Prof. Dr. Johanna Plendl Dritter Gutachter: Univ.-Prof. Dr. Achim Gruber Deskriptoren (nach CAB-Thesaurus): dogs, patella, dislocations, knees, surgical operations Tag der Promotion: 19.06.2019 Index Abbreviations ............................................................................................................................. 4 1. Introduction ............................................................................................................................ 5 2. Anatomy and biomechanics of the canine stifle joint ............................................................ 6 2.1 Functional anatomy of the canine stifle joint ....................................................................... 6 2.2 Patella and quadriceps muscle group ................................................................................... 6 2.3 Cranial cruciate ligament ..................................................................................................... 7 2.4 Caudal cruciate ligament ...................................................................................................... 8 2.5 Collateral ligaments .............................................................................................................. 8 2.6 Menisci ................................................................................................................................. 8 2.7 Biomechanics of the stifle joint............................................................................................. 9 3. Pathophysiology ................................................................................................................... 12 3.1 Theory I .............................................................................................................................. 13 3.2 Theory II ............................................................................................................................. 14 4. Patellar luxation .................................................................................................................... 15 4.1 Patellar luxation types: acquired and congenital ................................................................ 15 4.2 Statistical analysis of patellar luxation ............................................................................... 16 4.3 Pathophysiology of medial patellar luxation ...................................................................... 17 4.3.1 Malalignment of the quadriceps muscle group ............................................................... 18 4.3.2 Hypoplasia of the femoral trochlear groove and angular deformations .......................... 19 4.3.3 Osteological conformation .............................................................................................. 19 4.3.4 Estradiol levels ................................................................................................................ 21 4.4 Clinical presentation and diagnosis of patellar luxation .................................................... 21 4.4.1 Clinical signs and grades of patellar luxation ................................................................. 21 4.4.2 Diagnosing medial patellar luxation ............................................................................... 23 5. Cranial cruciate ligament rupture ......................................................................................... 25 5.1 Trauma ............................................................................................................................... 25 5.2 Degeneration and age ......................................................................................................... 26 5.3 Anatomical malformations ................................................................................................. 27 5.4 Immunomediated degeneration .......................................................................................... 28 5.5 Breed, sex, weight and sedentary lifestyle ......................................................................... 29 5.6 Clinical signs and diagnostic methods ............................................................................... 30 5.7 Correlations between meniscal disease, arthrosis and CCLR ............................................ 32 5.8 Patellar luxation and concomitant CCLR in small breed dogs .......................................... 32 1 6. Surgical treatment for PL and concomitant CCLR .............................................................. 34 6.1 “Trochlear wedge recession”.............................................................................................. 35 6.2 “Tibial tuberosity transposition” ........................................................................................ 36 6.3 Surgical techniques for cranial cruciate ligament deficiency ............................................. 36 6.3.1 Intracapsular – “Over-the-top graft” ............................................................................... 36 6.3.2 Extracapsular – “Capsular fascial imbrication” .............................................................. 37 7. Materials and Methods ......................................................................................................... 39 7.1 Study and patients .............................................................................................................. 39 7.2 Clinical examination .......................................................................................................... 42 7.3 Radiological examination ................................................................................................... 45 7.4 Surgery ............................................................................................................................... 46 7.4.1 Surgical procedures ......................................................................................................... 46 7.4.2 Complications .................................................................................................................. 49 7.4.3 Follow-up examinations and outcomes ........................................................................... 49 7.5 Statistical analysis .............................................................................................................. 51 8. Results .................................................................................................................................. 52 8.1 Breeds ................................................................................................................................. 53 8.2 Sex ...................................................................................................................................... 56 8.3 Weight – overweight .......................................................................................................... 57 8.4 Age ..................................................................................................................................... 58 8.5 Patellar luxation .................................................................................................................. 59 8.5.1 Type and direction ........................................................................................................... 59 8.5.2 Grade and affected side ................................................................................................... 61 8.6 Weight – overweight – castration ....................................................................................... 64 8.7 Cranial cruciate ligament rupture ....................................................................................... 65 8.7.1 Unilateral and bilateral .................................................................................................... 65 8.7.2 Timing of bilateral rupture .............................................................................................. 66 8.8 Meniscal disease ................................................................................................................. 67 8.9 Follow-up ........................................................................................................................... 68 8.9.1 Clinical examinations ...................................................................................................... 69 8.9.2 Owners questionnaires..................................................................................................... 70 8.10 Complications ................................................................................................................... 72 9. Discussion ............................................................................................................................ 73 2 9.1 Study and patients .............................................................................................................