Avulsion of muscles from the femoral trochanter in the fowl

Further studies on collateral ligaments of knee and intertarsal joints in domestic fowl

Collateral ligament attachments in distal femora and distal tibiotarsi were examined in broilers on ad libitum and restricted feeding and in laying strain fowls fed ad libitum. Histopathological studies revealed morphological changes in ligaments of ad libitum-fed broilers which were less apparent or absent in other birds examined. One such change was loss of crimp pattern in collagen bundles of ligaments, which suggested that structural derangement had occurred. Chondroid metaplasia and foci of hyaline cartilage were observed in ligaments of ad libitum-fed broilers and may result from tissue ischaemia. Similarities were noted between ligament attachments in broilers and Osgood-Schlatter disease in man; lesions in broilers may well have a similar aetiology. It is concluded that although feed restriction restores some semblance of normality in broiler ligaments, the propensity for abnormality remains and becomes apparent in heavier birds. Such reasoning casts doubt on the wisdom of modern broiler breeding practice where feed restriction can mask genotypic predisposition to clinical disease.

Rupture of the intercondylar ligament in intertarsal joints of broiler fowls

On examination of the intertarsal joints of approximately 150 lame broiler fowls, the intercondylar ligament was found to be ruptured, either partially or totally, in 22 birds. In some cases, rupture of the intercondylar ligament occurred in joints with gross angulation and usually in association with collateral ligament instability. In other birds, intercondylar ligament rupture occurred in limbs with minimal angulation but often with concomitant ligament or tendon failure in the same or contralateral limb. A fibrovascular layer was frequently identified between collateral ligaments and their distal tibiotarsal attachment. Haemorrhage in the fibrovascular tissue appears to be responsible for the establishment of the cyst-like structures which were present in some distal tibiotarsi.

Cruciate ligament rupture in young adult broiler knee joints

Derangement of the caudal cruciate ligament was identified in 11 broiler fowls aged between 18 and 38 weeks. In some cases, the caudal cruciate ligament alone was ruptured, whereas, in others, the caudal meniscofemoral and meniscotibial ligaments and medial meniscus were also deranged. In some birds, ligaments were only partially ruptured but, in 5 cases, complete rupture had occurred in both knee joints. All birds showed severe lameness which, in 2 cases, could only be ascribed to caudal cruciate derangement. Degenerative changes were present in many of the ligaments which suggested that rupture may be a consequence of primary ligamentous change. Proximal tibiotarsal osteochondrosis was a frequent concomitant finding which may affect the integrity of the ligament attachment. A number of other factors including postural abnormality, obesity, and relative inactivity may predispose broilers to caudal cruciate ligament rupture.