Production of patellar lesions by medial patellar desmotomy in normal horses

Medial patellar desmotomy was performed on one (treated) hindlimb, and a sham operation on the other (control) hindlimb, of 12 normal horses. The horses were examined for lameness before medial patellar desmotomy and at months 1, 2, and 3. The femoropatellar joints were examined radiographically and arthroscopically at month 3. All horses were lame on the treated limb at months 1, 2, or 3. Radiographic changes, including fragment formation at the distal aspect of the patella and bone production at the attachment of the middle patellar ligament on the patella, were present in 11 horses at month 3. Articular cartilage fibrillation or detachment was seen arthroscopically on the patellas of all treated limbs. In six horses, loosely attached fragments of bone and cartilage were removed arthroscopically from the distal aspect of the patella of the treated limb. The control limbs were clinically, radiographically, and arthroscopically normal throughout the study. Medial patellar desmotomy results in pathologic changes in the articular cartilage of the patella and adjacent soft tissues. Use of this surgical procedure should be reserved for persistent and confirmed cases of upward fixation of the patella.     

Ultrasonographic changes of the equine stifle following experimental medial patellar desmotomy

The objective of this study was to evaluate, through ultrasonography, the effect of medial patellar desmotomy. Middle patellar desmitis, enthesophytes in the patella, and irregularities in the cartilage of the femoral trochlear groove were observed. Medial patellar desmotomy leads to lesions in the stifle, and restriction of movement does not prevent these lesions from occurring.     

Latero-distal transposition of the tibial crest in cases of medial patellar luxation with patella alta

Medial patellar luxation is defined as medial displacement of the patella from the trochlear groove. In dogs, medial luxations account for 75% of all patellar luxation cases, and are frequently associated with patella alta. Common surgical treatments for medial luxation are trochleoplasty and lateral transposition of the crest to drive the patella into the correct anatomical alignment. Postoperative complications for this procedure are estimated to be between 18-29% of cases, with up to 48% of complications involving reluxation. It was previously hypothesized that in cases of medial luxation involving patella alta, the addition of a distal component to the lateral tibial crest transposition will result in repositioning of the patella into its proper position in the trochlear groove, thus reducing the recurrence of luxation. We performed this modified procedure on 14 dogs (17 limbs) that were suffering from medial luxation combined with patella alta, and our results led to favourable clinical outcomes. This modified surgical procedure places the patella into a more normal proximo-distal anatomical position, is simple to perform, and may become common practice for surgical treatment of medial patellar luxation with an alta component.     

Distal luxation of the patella in a horse

A 19-year-old Thoroughbred gelding presented with sudden onset, non-weight bearing lameness in the right hindlimb. Radiography confirmed distal luxation of the patella, which was replaced into its normal anatomical location under general anaesthesia. There were no pathological sequelae noted on follow-up examination 9 months after the initial injury. To our knowledge, this is a rare manifestation of patellar luxation, only reported once previously in the equine literature.     

Surgical treatment of navicular syndrome in the horse using navicular suspensory desmotomy

Seventeen horses diagnosed as having navicular syndrome on the basis of history, clinical findings, regional local anaesthesia and radiography were subjected to bilateral navicular suspensory desmotomy. Before surgery, the duration of navicular lameness ranged from 6 weeks to 4 years. Previous unsuccessful treatments prior to surgery included nonsteroidal anti-inflammatories, corrective shoeing, rest and isoxsuprine. For the seventeen horses subject to surgery, twelve horses were sound, one horse was improved and four horses were lame at a minimum of 6 months after surgery.     

Proximodistal alignment of the canine patella: radiographic evaluation and association with medial and lateral patellar luxation

Objectives— To evaluate the contribution of proximodistal alignment of the patella to patellar luxation, and to evaluate the structures contributing to proximodistal alignment of the patella relative to the femoral trochlea.
Study Design— Retrospective study using a convenience sample.
Animals— Medium to giant breed dogs (n=106).
Methods— Medical records and stifle radiographs of 106 dogs were reviewed. Radiographic measurements evaluated the proximodistal alignment of the patella with respect to the femoral trochlea, distal aspect of the femur, and proximal aspect of the tibia. Measurements were compared between dogs with clinically normal stifles (controls; n=51 dogs, 66 stifles), and dogs with a clinical diagnosis of medial patellar luxation (MPL, n=46 dogs, 65 stifles) or lateral patellar luxation (LPL, n=9 dogs, 11 stifles) using ANOVA.
Results— In dogs with MPL, the ratio of patellar ligament length (PLL) to patellar length (PL) was increased, as was the ratio of the distance from the proximal aspect of the patella to the femoral condyle (A) to PL ( P <.0001). Dogs with LPL had a decreased A:PL ( P =.003) and an increased ratio of the proximal tibial length (PTL) to distal tibial width (DTW; P =.009).
Conclusions— MPL is associated with a relatively long patellar ligament and patella alta in medium to giant breed dogs. LPL is associated with a relatively long proximal tibia and patella baja. Values for PLL:PL>2.06 and A:PL>2.03 are suggestive of the presence of patella alta, whereas a value for A:PL<1.92 is suggestive of patella baja.
Clinical Relevance— Measurements of both PLL:PL and A:PL are recommended in dogs with patellar luxation, and surgical correction should be considered in those with abnormal values.     

Surgical management of proximal articular fracture of the patella in a horse

A patellar fracture was identified radiographically in the right stifle of a mature Tennessee Walking Horse stallion. The horse was markedly lame (grade IV/V) on the right hindlimb. Due to the articular nature and small size of the fragment, surgical removal via arthrotomy was selected. A dorsomedial approach to the femoropatellar joint was used. The horse recovered well and has returned to training as a show horse by 8 months following surgery.     

Surgical correction of congenital medial patellar luxation in a llama

Unilateral congenital medial patellar luxation in a young llama was corrected by medial joint capsule release, tibial crest transposition, trochleoplasty, and lateral joint capsule imbrication. The techniques used were the same as described in the dog. One year after surgery, the llama was not lame, but had a valgus deformity originating at the stifle, most likely caused by lateral femoral condyle hypoplasia.     

Evaluation of inferior check ligament desmotomy for treatment of acquired flexor tendon contracture in the horse

The usefulness of inferior check ligament desmotomy as a treatment for acquired tendon contracture in horses was evaluated in 13 cases of deep digital flexor (DDF) contracture and in 3 cases of combined superficial digital flexor (SDF) and DDF contracture. In 8 of 9 cases of DDF contracture in which the dorsal surface of the hoof had not passed beyond being vertical to the ground, the surgical procedure was successful in returning the limb to a normal position and function. Compared with DDF tenotomy, inferior check ligament desmotomy was a superior treatment technique because of decreased postoperative pain, better postoperative appearance, and improved return to function. In 4 cases of DDF contracture in which the dorsal SDF contracture was also involved, inferior check ligament desmotomy was generally insufficient to allow return of the limb to normal alignment and function.     

Osteomyelitis of the medial trochlear ridge of the talus in a horse

A 12‐year‐old Quarter Horse gelding was evaluated for chronic recurrent right hindlimb cellulitis and severe lameness. Chronic tibiotarsal joint sepsis and osteomyelitis of the medial trochlear ridge were diagnosed and confirmed cytologically, arthroscopically and histologically. Trauma and secondary cellulitis and chronic septic arthritis were suspected aetiological factors.     

Surgical management of a pony with a traumatic medial luxation of the patella

This report describes a successful surgical repair of medial patellar luxation in a Miniature Shetland pony where manual reduction of the patella was not possible. The surgical procedure involves transection of the medial femoropatellar ligament to facilitate patellar release, the placement of a prosthetic suture to replace the lateral femoropatellar ligament and reinforcement of the lateral retinaculum by the use of a mesh implant. This is a newly described surgical technique for the rare but recognised condition of a medial luxation of the patella.