The use of radiofrequency energy (RFE) has become increasingly popular in equine orthopedic surgery in recent years, particularly for the debridement of cartilage lesions and soft tissue resection. However, despite considerable advancements in the technology, the safety and efficacy of RFE have continued to be questioned. While studies investigating the use of RFE for chondroplasty in the equine population are lacking, there is an abundance of research studies in the human literature assessing its effect on healthy chondrocytes, and researchers are seeking to develop guidelines to minimize collateral damage. This review article provides a concise and thorough summary of the current use of RFE in equine orthopedics, in addition to discussing the recent evidence surrounding its use for chondroplasty in both the human and equine populations.
Objective—To compare the mesenchymal stem cell (MSC) yield and chondrogenic and osteogenic differentiation from 5- and 50-mL bone marrow aspirates from horses.
Animals—Six 2- to 5-year-old mixed-breed horses.
Procedures—2 sequential 5-mL aspirates were drawn from 1 ilium or sternebra. A single 50-mL aspirate was drawn from the contralateral ilium, and 2 sequential 50-mL aspirates were drawn from a second sternebra. The MSC yield was determined through the culture expansion process. Chondrogenesis and osteogenesis were evaluated by means of conventional laboratory methods.
Results—The second of the 2 sequential 50-mL sternal aspirates yielded few to no MSCs. Independent of location, the highest density of MSCs was in the first of the 2 sequential 5-mL fractions, although with subsequent culture expansion, the overall yield was not significantly different between the first 5-mL and first 50-mL fractions. Independent of location, chondrogenesis and osteogenesis were not significantly different among fractions. Independent of fraction, the overall cell yield and chondrogenesis from the ilium were significantly higher than that from the sternum.
Conclusions and Clinical Relevance—This study failed to detect an additional benefit of 50-mL aspirates over 5-mL aspirates for culture-expanding MSCs for equine clinical applications. Chondrogenesis was highest for MSCs from ilial aspirates, although it is not known whether chondrogenesis is indicative of activation of other proposed pathways by which MSCs heal tissues.
Objective—To determine clinical and ultrasonographic
abnormalities in horses with primary desmitis of
the palmar or plantar annular ligament (PAL) and the
response to treatment.
Procedure—Data collected from medical records
included signalment, horse use, affected limb, severity
and duration of lameness, results of diagnostic
tests performed, ultrasonographic findings, treatment,
Results—All horses had a prominent swelling in the
region of the affected PAL, and signs of pain were evident
during palpation of the swelling. In all horses,
the affected PAL was thicker than normal as determined
ultrasonographically. Twenty horses had hypoechoic
regions in the PAL. Four horses, including 1
horse with 3 affected limbs, were treated by means
of PAL desmoplasty, 9 were treated by means of PAL
desmotomy, and 12 were treated with rest. Follow-up
information was available for 21 horses. All 4 horses
that underwent PAL desmoplasty, 4 of 7 horses that
underwent PAL desmotomy, and 7 of 10 horses treated
with rest alone became sound.
Conclusions and Clinical Relevance—Results suggest
that primary desmitis of the PAL may be a cause
of lameness in horses. Although significant differences
in outcome between horses treated with rest
alone versus PAL desmoplasty versus PAL desmotomy
were not identified, because it is less invasive,
PAL desmoplasty should be considered for treatment
of horses with PAL desmitis that do not respond to
conservative treatment and do not have any evidence
of constriction of the digital flexor tendons. (J Am Vet
Med Assoc 2005;226:83–86)
Objective—To evaluate healing of pinch-grafted
wounds on the distal aspect of the limbs of ponies
bandaged with equine amnion or a standard nonadherent
wound dressing material.
Procedure—A 2.5 × 2.5-cm full-thickness section of
skin was removed from the dorsal aspect of each
limb at the midpoint of the metacarpus or metatarsus.
Six days later, wounds were grafted with partial-thickness
pinch grafts. Half the wounds were bandaged
with amnion, and the other half were bandaged with
a nonadherent dressing. Bandages were changed
every 3 days until wound healing was complete. At
each bandage change, numbers of grafts lost were
recorded, and wounds were measured.
Results—Percentage of grafts lost from wounds bandaged
with amnion was not significantly different
from percentage lost from wounds bandaged with
the nonadherent dressing. Median healing time for
wounds bandaged with amnion (30 days) was significantly
less than median healing time for wounds bandaged
with the nonadherent dressing (39 days). All
wounds were healed by day 45.
Conclusions and Clinical Relevance—Results suggest
that amnion can be used for bandaging pinchgrafted
wounds on the distal aspect of the limbs of
ponies. (Am J Vet Res 2000;61:326–329)
Objective—To evaluate the effect of fibrin concentrations on mesenchymal stem cell (MSC) migration out of autologous and commercial fibrin hydrogels.
Sample—Blood and bone marrow from six 2- to 4-year-old horses.
Procedures—Autologous fibrinogen was precipitated from plasma and solubilized into a concentrated solution. Mesenchymal stem cells were resuspended in fibrinogen solutions containing 100%, 75%, 50%, and 25% of the fibrinogen precipitate solution. Fibrin hydrogels were created by mixing the fibrinogen solutions with MSCs and thrombin on tissue culture plates. After incubation for 24 hours in cell culture medium, the MSCs that had migrated onto the tissue culture surface and beyond the boundary of the hydrogels were counted. This procedure was repeated with a commercial fibrin sealant.
Results—Hydrogel-to-surface MSC migration was detected for all fibrin hydrogels. Migration from the 25% autologous hydrogels was 7.3-, 5.2-, and 4.6-fold higher than migration from 100%, 75%, and 50% autologous hydrogels, respectively. The number of migrating cells from 100%, 75%, and 50% autologous hydrogels did not differ significantly. With commercial fibrin sealant, the highest magnitude of migration was from the 25% hydrogels, and it was 26-fold higher than migration from 100% hydrogels. The 75% and 50% hydrogels resulted in migration that was 9.5- and 4.2-fold higher than migration from the 100% hydrogels, respectively.
Conclusions and Clinical Relevance—MSC migration from fibrin hydrogels increased with dilution of the fibrinogen component for both autologous and commercial sources. These data supported the feasibility of using diluted fibrin hydrogels for rapid delivery of MSCs to the surface of damaged tissues.
To raise awareness of the potential for intra-articular subchondral bone sequestrum formation secondary to a traumatic or septic process to enable more rapid identification of this uncommon but possible outcome in future cases.
A client-owned 12-year-old Appaloosa mare.
CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES
The mare had a wound to the lateral aspect of the fourth metatarsal bone (MT4) that communicated with the distal tarsal joints. Radiographs revealed a displaced, comminuted fracture of MT4.
TREATMENT AND OUTCOME
The horse underwent aggressive debridement of the wound and MT4 as well as, on 2 occasions, needle joint lavage. Systemic, regional, and IA antibiotic therapy was also performed together with a bone graft from the tuber coxae. The horse’s comfort improved, and the wound appeared to be healing. Five weeks following discharge, the horse re-presented with a non–weight-bearing lameness and radiographs revealed marked osteomyelitis of the tarsometatarsal and distal intertarsal joints. Postmortem examination of the limb identified a sequestrum within the proximal articular surface of the third metatarsal bone.
The present report highlights the importance of arthroscopic lavage to visualize the cartilage surface and the benefits of advanced imaging to detect associated changes within the bone earlier than conventional radiographs. To our knowledge, no reports exist of intra-articular subchondral bone sequestra in the tarsometatarsal joint in horses.
OBJECTIVE To describe clinical use of a locking compression plate (LCP) for proximal interphalangeal joint (PIPJ) arthrodesis in horses and compare outcomes for horses that underwent the procedure as treatment for fracture of the middle phalanx (P2) versus other causes.
DESIGN Retrospective case series.
ANIMALS 29 client-owned horses.
PROCEDURES Medical records of 2 veterinary teaching hospitals from 2008 through 2014 were reviewed to identify horses that underwent PIPJ arthrodesis of 1 limb. Signalment, surgical, and outcome-related variables were recorded. Owners were contacted from 1 to 6 years after surgery to determine rehabilitation time, current use of the horse, and overall owner satisfaction with the procedure. Success was determined on the basis of owner satisfaction and outcome for intended use. Variables of interest were compared statistically between horses that underwent surgery for P2 fracture versus other reasons.
RESULTS 14 horses underwent surgery for treatment of P2 fracture, and 15 had surgery because of osteoarthritis, subluxation, or osteochondrosis. Median convalescent time after surgery (with no riding or unrestricted exercise) was 7 months. Four horses were euthanized; of 23 known alive at follow-up, 22 were not lame, and 18 had returned to their intended use (8 and 10 at higher and lower owner-reported levels of work, respectively). Horses undergoing arthrodesis for reasons other than fracture were significantly more likely to return to their previous level of work. Twenty-two of 24 owners contacted indicated satisfaction with the procedure.
CONCLUSIONS AND CLINICAL RELEVANCE Surgical arthrodesis of the PIPJ was successful in most horses of the study population. Various nuances of the system for fracture repair need to be understood prior to its use.
CASE DESCRIPTION A 12-year-old mixed-breed mare (horse 1) and 6-year-old Friesian gelding (horse 2) were examined for chronic lameness associated with the stifle joint.
CLINICAL FINDINGS Lameness examination revealed effusion of the right (horse 1) or left (horse 2) femoropatellar and medial femorotibial joints and grade 3/5 (horse 1) or 4/5 (horse 2) lameness. A diagnosis of cranial cruciate ligament (CCL) injury with associated mineralization and avulsion (horse 1) or mineralization alone (horse 2) was facilitated in both horses with a caudomedial-craniolateral oblique radiographic view obtained 45° medial to the caudocranial line, which highlighted the origin of the ligament on the caudoaxial aspect of the lateral femoral condyle within the intercondylar fossa. These lesions were subsequently confirmed via CT.
TREATMENT AND OUTCOME Arthroscopy of the medial and lateral femorotibial joints was performed for horse 1 and revealed the osseous fragment associated with the CCL, but the fragment could not be removed. Horse 2 was euthanized while anesthetized following CT owing to the poor prognosis.
CONCLUSIONS AND CLINICAL RELEVANCE Radiography is typically the first imaging modality attempted for horses with CCL injury, particularly outside the hospital setting. A 45° caudomedial-craniolateral oblique radiographic view may aid in diagnosis of CCL injury when avulsion or mineralization is present. Although this view is not commonly included in the typical radiographic series for imaging of the stifle joint in horses, it should be considered when CCL injury is suspected.
To perform a pilot study with the intent of assessing the feasibility of a modified subchondroplasty (mSCP) technique in a validated preclinical equine model of full-thickness articular cartilage loss and evaluate the short-term patient response to the injected materials.
3 adult horses.
Two 15-mm-diameter full-thickness cartilage defects were created on the medial trochlear ridge of each femur. Defects were treated with microfracture and then filled by 1 of 4 techniques: (1) autologous fibrin graft (FG) via subchondral injection of fibrin glue (FG), (2) autologous fibrin graft via direct injection of FG, (3) subchondral injection of a calcium phosphate bone substitute material (BSM) with direct injection of FG, and (4) untreated control. Horses were euthanized after 2 weeks. Patient response was evaluated via serial lameness examination, radiography, magnetic resonance imaging, computed tomography, gross evaluation, microcomputed tomography, and histopathology.
All treatments were successfully administered. The injected material perfused through the underlying bone into the respective defects without adversely affecting the surrounding bone and articular cartilage. Increased new bone formation was seen at the margins of the trabecular spaces containing BSM. There was no treatment effect on the amount or composition of tissue within defects.
The mSCP technique was a simple, well-tolerated technique in this equine articular cartilage defect model without significant adverse effects to host tissues after 2 weeks. Larger studies with long-term follow-ups are warranted.