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The implantation of unicortical cortex screws in the proximal hole of locking compression plates (LCP) has been recommended for proximal interphalangeal (PIP) arthrodesis in horses to prevent fractures resulting from stress risers in the proximal phalanx (P1). However, this cortex screw fixation technique may limit efficient dorsal compression of the PIP joint by the plate, potentially affecting the stability of the construct. In this study, we aimed to measure stress and strain in P1 and the plate using an ex vivo model of PIP arthrodesis in horses. We employed various implantation methods and proximal screw types in conjunction with two 5.5 mm transarticular cortex screws. Ten pairs of equine forelimbs were divided into four groups based on proximal screw placement: GUC (unicortically placed cortex screw), GBC (bicortically placed cortex screw), GUL (unicortically placed locking screw), and GBL (bicortically placed locking screw). We calculated the magnitude and direction of strain, strain ratio, and stress using strain gauges during an axial compression mechanical testing. The palmar surface of P1 exhibited higher stress and strains than the dorsal surface, with the plate part located at the articular level suffered more stress than the proximal part. Both the implantation method and proximal screw type significantly influenced the analyzed parameters. The GUC promoted greater changes in strain direction in the proximal portion of the P1. Bicortical placement of a cortex screw appears to be the most suitable option for filling the proximal hole of the LCP, because it allows effective dynamic compression via the plate and prevents abrupt shifts in the direction of the forces acting on the proximal part of P1 during loading., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier Ltd.)

Objectives: The aim of this study was to report the clinical outcomes in a series of traumatic elbow luxations in cats treated with closed reduction and a temporary transarticular type II external skeletal fixator (ESF)., Methods: A retrospective review was conducted of traumatic elbow luxation cases in cats at two referral centres. Data collected included signalment, history, clinical assessment, radiographic findings, surgical procedures and complications. Short-term follow-up was based on clinical evaluations at 2 and 6 weeks postoperatively. Long-term follow-up was based either on a telephone interview with the owner or a clinical evaluation., Results: Eight cats were included. Five cats experienced lateral elbow luxation, while three cats had medial elbow luxation. All cats with medial elbow luxation exhibited radiographic signs of medial humeral epicondylitis. The median age was 9 years (range 3-15). The elbow luxation was treated by closed reduction and percutaneous placement of a temporary transarticular type II ESF, which was removed 2 weeks postoperatively. Two minor complications were recorded. Elbow reluxation and major complications were not encountered. The 6-week postoperative evaluation and long-term follow-up revealed a lameness of grade 1 in 1/8 cats and 0 in the remainder. Elbow range of motion was normal in all cats., Conclusions and Relevance: None of the cases treated with this protocol experienced recurrence of elbow luxation. All cats demonstrated an excellent outcome based on the lameness score, the low complication rate and the follow-up telephone interview. The technique is minimally invasive and carries a low incidence of complications. Concurrent orthopaedic disease, such as medial humeral epicondylitis, may predispose to medial elbow luxation., Competing Interests: Conflict of interestThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

A 1-year-old male neutered ferret (Mustela putorius furo) was evaluated for an abnormal left cubital joint. Radiographs demonstrated a proliferative osseous lesion of the left proximal antebrachium. Computed tomography confirmed a large thin-walled expansile osseous lesion of the left proximal radius and identified multifocal proliferative lesions of the axial spine, two of which caused spinal cord compression. A left forelimb amputation with total scapulectomy was performed. Histopathology revealed a well-demarcated mass with a thin rim of mature lamellar bone and a discontinuous cartilage cap covered by a perichondrial/periosteal membrane continuous with the adjacent bone. Findings were most consistent with an osteochondroma or osteochondromatosis (i.e., multiple cartilaginous exostoses, hereditary multiple exostoses). No evidence of malignant transformation was observed within this specimen. Three months post-surgery, verbal correspondence with the owner confirmed return to normal activity level and no emergence of neurological signs. Repeat examination and imaging were recommended., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: To assess the feasibility of a novel transcoronal approach for the treatment of axial type 3 cysts of the palmar/plantar aspect of the distal phalanx (P3)., Study Design: Ex vivo, experimental study., Sample Population: Ten cadaveric specimens, four forelimbs and six hindlimbs., Methods: All cadaveric specimens underwent radiographically guided drilling, followed by cortical screw placement. The cartilage was macroscopically assessed after disarticulation of the distal interphalangeal joint. The entry point and trajectory were evaluated with computed tomography. Results were categorized as: axial, near-axial and abaxial. The minimal distance from the outer margin of the drill hole and the proximal border of the subchondral bone plate was measured using frontal computed tomographic slices., Results: Eight of the 10 screws were in an axial to near-axial position and nine followed the desired axial to near-axial trajectory. One screw was inserted axially but continued in an abaxial trajectory. Iatrogenic damage to the joint cartilage, flexor cortex and solar canal of P3 was not observed. All cortical screws were placed close to the proximal subchondral bone-plate of P3., Conclusion: The desired axial/near-axial drilling and screw placement, under radiographic guidance, was achieved in nine out of 10 specimens., Clinical Significance: This novel technique seems promising for the treatment of inaccessible P3 cysts. Additional studies are required to investigate its feasibility in clinical cases, and the long-term outcome following transcystic screw placement of type 3 P3 cysts., (© 2024 American College of Veterinary Surgeons.)

Objective: To establish racing prognosis in Thoroughbred yearlings with proximal sagittal ridge osteochondral lesions and compare them to dorsoproximal and palmar/plantar first phalanx osteochondral lesions., Animals: A total of 47 horses had proximal sagittal ridge lesions, 34 had palmar/plantar first phalanx lesions, and 115 had dorsoproximal first phalanx lesions., Study Design: Retrospective case series., Methods: Medical records of Thoroughbred yearling racing prospects treated arthroscopically for fetlock osteochondral lesions were reviewed. Data were collected from a public database, including the ability to train and race, earnings, starts, wins, and placed races. Racing prognosis was analyzed and compared between three lesion locations., Results: Of the proximal sagittal ridge group, 76.6% raced, 65.71% of the palmar/plantar first phalanx group, and 74.58% of the dorsoproximal first phalanx group. Career length was similar for all lesions. A lower number of "starts" in the group "five years old and older" was found for the dorsoproximal first phalanx group compared to the cohort with proximal sagittal ridge lesions. Mares had more "earnings" at two years old but fewer "starts" at "five years old" compared to colts and geldings. Forelimb lesions were predictive for fewer total career starts., Conclusion: Proximal sagittal ridge lesions had similar prognoses to dorsoproximal and palmar/plantar first phalanx lesions. In older horses, there was an increase in the number of starts for the proximal sagittal ridge group compared to the dorsoproximal first phalanx group. Mares and forelimb lesions were associated with decreased racing starts., Clinical Significance: These findings aid in prognostication for Thoroughbreds with osteochondral lesions removed arthroscopically in the fetlock joint., (© 2024 American College of Veterinary Surgeons.)

Case History: A 4-month-old male Shih Tzu dog (Case 1) and an 11-month-old female Devon Rex cat (Case 2) were referred to specialist veterinary hospitals for evaluation of right thoracic lameness and growth abnormality in the distal aspect of the forelimb., Clinical Findings: Non-weight-bearing lameness and decreased range of motion were noted in the affected limbs of both cases. Case 1 had a plantigrade stance, and a cleft separation between the first and second digits extending upwards to the distal third of the antebrachium. There was no pain on palpation, and the affected limb was shorter than the contralateral. Radiographic examination revealed cleft separation between metacarpal bones I and II, and carpal bone fusion (I, II, III), and the distal radius ended freely and was attached to the first metacarpal bone.Case 2 had a small cleft medial to metacarpal III. The limb was consistently held in abduction and had marked carpal varus. The limb had never been used for weight bearing. Radiographic examination showed agenesis of metacarpal bone II and separation of metacarpals I and III. The radius and ulna were separated and the radial head did not articulate normally at the elbow, leading to marked elbow incongruity., Diagnosis: Ectrodactyly in both cases., Treatment and Outcome: Amputation of the radius followed by ulnocarpal arthrodesis were performed in both cases. Follow-up evaluations up to 1 year (Case 1) and 10 weeks (Case 2) after surgery indicated satisfactory arthrodesis fusion, owner satisfaction, and a good clinical outcome., Clinical Relevance: Ectrodactyly is a rare congenital deformity of the forelimb with a heterogeneous character, requiring an individualised treatment plan. These are the first cases reported in the literature of ectrodactyly in small animals that were treated successfully with ulnocarpal arthrodesis. This case series therefore provides evidence in support of this treatment option for this heterogeneous congenital deformity.

Objective:  The aim of this study was to assess if the level of osteotomy (50 or 75% the length of the humerus), osteotomy angle (5, 10, or 20 degrees), direction of bone alteration (external rotational or medial opening wedge osteotomies), or orientation of osteotomy (perpendicular to the humeral long axis or perpendicular to the weight-bearing axis of the limb) affect pressure through the medial compartment of the elbow., Study Design:  Humeral osteotomies were performed at 50 and 75% the length of the humerus on 12 canine cadaver thoracic limbs and patient-specific three-dimensional (3D) printed plates applied to induce the desired alteration. Sensors were placed into the medial and lateral aspects of the elbow joint and the limb compressed to 90 N in a universal testing system., Results:  Increasing the angle of the induced change had a significant effect on the decreased load through the medial compartment. Performing the osteotomy at 75% of humeral length from proximal was significantly more effective at reducing the medial elbow load than performing it at 50%. Opening wedge osteotomies were more effective than external rotational osteotomies, but both were effective. Changing the direction of the osteotomy (comparing transverse to oblique) did not significantly affect the load reduction through the medial compartment., Conclusion:  Performing an osteotomy at a more distal location along the humerus and increasing the angle of the induced change increased the effectiveness of load-shifting humeral osteotomies., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective: Evaluate whether total elbow replacement (TER) through a lateral approach is accurate and stable., Animals: 12 skeletally mature large-breed dog cadavers were used., Methods: Limb alignment, elbow joint motion, and collateral ligament laxity were evaluated preoperatively. The order of surgery (left or right) and the approach (lateral or medial) were randomly selected for TER in each dog. The other approach was used in the contralateral elbow. Intraoperative technical difficulties, duration of surgery, and anatomic complications were recorded. Limb alignment, elbow joint motion, collateral ligament laxity, and prosthetic component alignment were evaluated after surgery. Data were collected from June 11 to 15, 2023., Results: The duration of surgery using a lateral or medial approach did not differ (P = .499). Anatomic complications were not observed. The lateral approach resulted in 8° more elbow extension (P = .003), 1.58° less lateral collateral ligament constraint (P = .033), 2.80° less medial collateral ligament constraint (P = .002), 4.38° less frontal plane constraint (P = .004), 8° greater humeral component inclination (P = .033), and 5.6° greater radioulnar component varus (P = .001) than the medial approach. Varus of the radius, mechanical axis deviation, limb supination, elbow flexion, mediolateral humeral component and craniocaudal radioulnar component orientation did not differ among joints operated using a lateral or medial approach. In normal cadaveric elbows, a lateral approach for TER appears feasible, producing equivalent limb alignment, joint laxity, and joint motion to normal elbows and to TER placed using a medial approach., Clinical Relevance: In dogs, TER can be performed using a lateral surgical approach.

Osteosarcoma treatment with limb-sparing surgery using liquid nitrogen can be applied to canine patients experiencing diminished quality of life after leg amputation. In particular, forelimb amputation may affect gait more than hindlimb amputation. In this study, limb-sparing surgery using liquid nitrogen was applied to primary osteosarcomas arising in the proximal scapula of a Welsh Corgi, the proximal humerus of a Golden Retriever, and the distal radius of a Great Pyrenees, according to the protocol of Tsuchiya et al. In all cases, postoperative radiographic examination revealed bone union between the treated and matrix bones. All patients recovered their gait postoperatively. These results suggest that limb-sparing surgery using liquid nitrogen-treated autologous bone is an effective option for patients with osteosarcoma.

Objective: To report a case of unilateral lateral coronoid process fragmentation in a dog treated via lateral elbow arthroscopy portals., Animal: A 9-month old male intact English Bulldog., Study Design: Case report., Methods: The dog presented with a history of intermittent right thoracic limb lameness. Orthopedic examination on presentation was unremarkable. Computed tomography of the right thoracic limb was pursued and revealed a mineralized focus along the lateral margin of the lateral coronoid process as well as sclerosis of the medial coronoid process and subtrochlear region of the ulna. Elbow arthroscopy was performed via a lateral approach and revealed chondromalacia of the entire lateral coronoid process. Abrasion arthroplasty of the lateral coronoid process was performed., Results: Complete resolution of the lameness was achieved within two weeks of surgery. At 6 weeks postoperatively, the dog remained sound and a gradual return to normal activity was recommended. At the final follow up assessment, 5 months after surgery, no abnormalities were found on orthopedic examination and the owners reported excellent limb function with no observable lameness., Conclusion: Lateral coronoid disease can occur as a rare component of elbow dysplasia in dogs. Abrasion arthroplasty via lateral arthroscopic portals may have resulted in a successful outcome in this case and may form an effective treatment option for lateral coronoid disease in dogs., (© 2024 The Authors. Veterinary Surgery published by Wiley Periodicals LLC on behalf of American College of Veterinary Surgeons.)

Objective: Chronic foot pain, a common cause of forelimb lameness, can be treated by palmar digital neurectomy (PDN). Complications include neuroma formation and lameness recurrence. In humans, neuroanastomoses are performed to prevent neuroma formation. The aim of the study was to evaluate the outcome of horses undergoing dorsal-to-palmar branch neuroanastomosis following PDN., Study Design: Retrospective case series., Animals: Eighty-five horses with PDN and dorsal-to-palmar branch neuroanastomosis., Methods: Medical records for horses undergoing this procedure at two hospitals between 2015 and 2020 were reviewed. Palmar and dorsal nerve branches of the PDN were transected and end-to-end neuroanastomosis was performed by apposition of the perineurium. Follow-up was obtained from medical records and telephone interviews. Success was defined as resolution of lameness for at least one year., Results: Lameness resolved following surgery in 81/85 (95%) horses with 57/84 (68%) sound at one year. Postoperative complications occurred in 19/85 (22%) cases. The main limitations of the study were an incomplete data set, inaccurate owner recall, and variations in procedure., Conclusion: Compared to previous studies, this technique resulted in similar numbers of horses sound immediately after surgery, a comparable rate of postoperative neuroma formation but a higher recurrence of lameness rate at 1 year postoperatively., Clinical Significance: End-to-end neuroanastomosis of the dorsal and palmar branches of the PDN does not reduce the rate of neuroma formation in horses. Long-term outcome was less favorable compared to previously reported PDN techniques., (© 2024 American College of Veterinary Surgeons.)

Objective: To determine the ability to completely transect the equine accessory ligament of the deep digital flexor tendon (AL-DDFT) via an ultrasonographically-guided, percutaneous looped thread desmotomy using FiberWire suture as a cutting device., Study Design: Ex-vivo study., Sample Population: A total of 24 normal equine distal forelimb specimens., Methods: Under ultrasonographic guidance, a Jamshidi needle was placed between the suspensory ligament and the AL-DDFT, and between the AL-DDFT and the deep digital flexor tendon, through two stab incisions. FiberWire suture was fed through the needle and looped around the AL-DDFT. Using a sawing motion, the ligament was transected, and the suture exited through the lateral incision. Surgical sites were dissected and assessed for completeness of transection, iatrogenic injuries, and suture remnants. Descriptive statistics were reported., Results: The procedure met the successful criteria in 18/24 (75%) of the limbs. The median surgical time was 11 min (range 7-25). No suture failure or suture remnants were noted in any of the specimens. Complications included iatrogenic injury to the medial and lateral neurovascular bundles in 4/24 and 1/24 specimens, respectively., Conclusion: Complete transection of the AL-DDFT was achieved in 22/24 (92%) of the specimens; however, the neurovascular bundles were injured in 5/24 (21%) of the specimens., Clinical Significance: A percutaneous looped thread desmotomy of the AL-DDFT can be studied as an alternative technique for use in equine models prior to its clinical use in patients. Additional studies are required to evaluate efficacy and safety in anesthetized or standing horses., (© 2023 American College of Veterinary Surgeons.)

Objective:  The aim of this study was to assess the outcome of arthroscopic subtotal coronoidectomy in treating medial coronoid disease and the effect of concurrent autologous conditioned plasma (ACP) in dogs using force plate analysis., Study Design:  This study included 16 dogs with unilateral medial coronoid disease based on computed tomographic imaging. Treatment consisted of an arthroscopic subtotal coronoidectomy. As concurrent therapy, eight dogs received ACP at the end of the arthroscopy and eight dogs a placebo. Force plate analysis, including vertical forces, braking and propulsive forces, corresponding impulses and symmetry indices, was performed prior to arthroscopy and at 4, 12 and 26 weeks postoperatively., Results:  After an initial reduction of all force plate analysis parameters, vertical and propulsive parameters gradually improved to the level of healthy dogs at 26 weeks postoperatively. In contrast, braking parameters did not reach normal values at 26 weeks, demonstrating ongoing loss of elbow joint function. The ACP and placebo group did not show any significant difference in force plate analysis parameters during the 26 weeks study period., Conclusion:  Arthroscopic subtotal coronoidectomy did not result in complete normalization of ground reaction forces, impulses and symmetry indices. Concurrent treatment with ACP, immediately after arthroscopy, did not improve outcome. Our results show that outcome of arthroscopic subtotal coronoidectomy in treating medial coronoid disease is less favourable than previously reported., Competing Interests: None declared., (Thieme. All rights reserved.)

Introduction: Above elbow transplants represent 19% of the upper extremity transplants. Previous large-animal models have been too distal or heterotopic, did not use immunosuppression and had short survival. We hypothesize that an orthotopic forelimb transplant model, under standard immunosuppression, is feasible and can be used to address questions on peri-transplant ischemia reperfusion injury, and post-transplantation vascular, immunologic, infectious, and functional outcomes., Materials and Methods: Four forelimbs were used for anatomical studies. Four mock transplants were performed to establish technique/level of muscle/tendon repairs. Four donor and four recipient female Yucatan minipigs were utilized for in-vivo transplants (endpoint 90-days). Forelimbs were amputated at the midarm and preserved through ex vivo normothermic perfusion (EVNP) utilizing an RBC-based perfusate. Hourly perfusate fluid-dynamics, gases, electrolytes were recorded. Contractility during EVNLP was graded hourly using the Medical Research Council scale. EVNP termination criteria included systolic arterial pressure ≥115 mmHg, compartment pressure ≥30 mmHg (at EVNP endpoint), oxygen saturation reduction of 20%, and weight change ≥2%. Indocyanine green (ICG) angiography was performed after revascularization. Limb rejection was evaluated clinically (rash, edema, temperature), and histologically (BANFF classification) collecting per cause and protocol biopsies (POD 1, 7, 30, 60 and endpoint). Systemic infections were assessed by blood culture and tissue histology. CT scan was used to confirm bone bridging at endpoint., Results: Animals 2, 4 reached endpoint with grade 0-I rejection. Limbs 1, 3 presented grade III rejection on days 6, 61. CsA troughs averaged 461 ± 189 ng/mL. EVNLP averaged 4.3 ± 0.52 h. Perfusate lactate, PO 2 , and pH were 5.6 ± 0.9 mmol/L, 557 ± 72 mmHg and 7.5 ± 0.1, respectively. Muscle contractions were 4 [1] during EVNLP. Transplants 2, 3, 4 showed bone bridging on CT., Conclusion: We present preliminary evidence supporting the feasibility of an orthotopic, mid-humeral forelimb allotransplantation model under standard immunosuppression regimen. Further research should validate the immunological, infectious, and functional outcomes of this model., (© 2024 The Authors. Microsurgery published by Wiley Periodicals LLC.)

Objective: To compare the accuracy of three-dimensional (3D) printed patient-specific guide (PSG) with a freehand (FH) approach for radial osteotomies in ex vivo normal dogs., Study Design: Experimental study., Animals: Twenty four ex vivo thoracic limb pairs from normal beagle dogs., Methods: Computed tomography (CT) images were collected preoperatively and postoperatively. Three osteotomies tested (n = 8/group) were: (1) uniplanar 30° frontal plane wedge ostectomy, (2) oblique plane (30° frontal, 15° sagittal) wedge ostectomy, and (3) single oblique plane osteotomy (SOO, 30° frontal, 15° sagittal, and 30° external). Limb pairs were randomized to a 3D PSG or FH approach. The resultant osteotomies were compared with virtual target osteotomies by surface shape-matching postoperative to the preoperative radii., Results: The mean ± standard deviation osteotomy angle deviation for all 3D PSG osteotomies (2.8 ± 2.8°, range 0.11-14.1°) was less than for the FH osteotomies (6.4 ± 6.0°, range 0.03-29.7°). No differences were found for osteotomy location in any group. In total, 84% of 3D PSG osteotomies were within 5° deviance from the target compared to 50% of freehand osteotomies., Conclusion: Three-dimensional PSG improved FH accuracy of osteotomy angle in select planes and the most complex osteotomy orientation in a normal ex vivo radial model., Clinical Significance: Three-dimensional PSGs provided more consistent accuracy, which was most notable in complex radial osteotomies. Future work is needed to investigate guided osteotomies in dogs with antebrachial bone deformities., (© 2023 The Authors. Veterinary Surgery published by Wiley Periodicals LLC on behalf of American College of Veterinary Surgeons.)

The giant anteater ( Myrmecophaga tridactyla ) is a neotropical mammal considered to be vulnerable to extinction. Recent increased interest in veterinary care in the giant anteater has prompted renewed interest in anatomical descriptions in this species. The terrestrial habits and slow movements of the giant anteater contribute to its susceptibility to vehicular trauma on highways, which is a significant cause of mortality in the species. This study describes the muscular anatomy of the thoracic limb and variations of the long bones with emphasis on the structures surrounding the humerus and radius. It also describes the possible surgical approaches for the management of fractures of humerus and radius, comparing these with the surgical approaches described in dogs ( Canis lupus familiaris ). Three giant anteater and three domestic dog cadavers, from deaths not related to this project, were used. The medial approach to the humeral diaphysis of the giant anteater resulted in the least tissue trauma, and provided access to the flattest surface for implant attachment. The lateral approach to the radius proved challenging, requiring total detachment of the extensor carpi radialis muscle and incision of the very robust abductor digitorum longus muscle to access the distal diaphysis. Although the giant anteater shares many similarities of the thoracic limb anatomy with the domestic dog, important differences exist. This comparative knowledge will allow veterinary practitioners to directly apply the principles of fracture repair in these species. Safe access to these bones for possible osteosynthesis is essential to allow implant placement and minimize postoperative complications in this species.

Objective: To describe the feasibility of a novel thread-transecting technique for the tenotomy of the equine deep digital flexor tendon (DDFT)., Animals: 39 equine distal limb specimens., Methods: Under ultrasonographic guidance, a surgical thread was percutaneously placed around the DDFT through 2 needle punctures (lateral and medial) using a Tuohy needle in equine limbs (22 forelimbs, 17 hindlimbs). The DDFT was transected by a back-and-forth motion of the thread until the loop emerged from the entry puncture site. Each specimen was dissected and assessed for completeness of transection and iatrogenic damage under direct visualization. Descriptive statistics were reported., Results: Complete DDFT transection was achieved in all 39 limbs, taking an average of 8.6 minutes per procedure. Iatrogenic damage to surrounding structures occurred in 17 (44%) limbs, with 6 (15%) limbs having more than 1 structure damaged. Damage to the communicating branch of the palmar or plantar nerves was the most commonly seen., Clinical Relevance: DDFT tenotomy in equine limb specimens was effectively performed using a novel thread-transecting technique. The procedure is quick, and no suturing is needed, but damage to surrounding structures is possible. Further assessment of the procedure and clinical significance of its potential iatrogenic damage in clinical cases is needed.

Case History: Dogs (n = 15) that were presented to a single veterinary teaching hospital with elbow dysplasia-associated lameness between September 2021 and May 2022, and were determined to require arthroscopy based on imaging results, were prospectively recruited into the study. The median duration of lameness was 4 (min 1, max 24) months., Clinical Findings: Various breeds were represented with a median body weight of 31.6 (min 15, max 46.4) kg and median age at presentation of 14 (min 8, max 83) months. Results of imaging modalities (CT) were consistent with medial coronoid disease with fissured or fragmented medial coronoid process in all dogs., Arthroscopic Findings: Feasibility of the needle arthroscopy (NA) procedure was firstly assessed in a preliminary cadaveric study in forelimbs (n = 10) collected from 10 adult dogs euthanised for reasons unrelated to the study. Elbow exploration was performed through a medial approach beginning with NA (1.9 mm 0° angle scope) followed by standard arthroscopy (SA; 2.4 mm 30° angle scope). The quality and extent of visualisation (scored through the number of anatomical structures visualised) were recorded and statistically compared. As the cadaver study indicated that NA allowed safe inspection of all structures in medial/caudal compartments, this procedure was then used in the dogs requiring treatment. In the clinical setting, elbow exploration was successful in all dogs and the treatment (removal of osteochondral fragments) was performed without requiring conversion into SA. One month after surgery, all dogs had an improvement in their lameness score (0-5) and 12/15 dogs were no longer lame. There was a reduction in Canine Orthopaedic Index scores measured a median of 99 (min 47, max 180) days after surgery (24 (IQR 19.5-31.5)) compared to the pre-operative period (49 (IQR 46.5-57); p < 0.001)., Clinical Relevance: Needle arthroscopy-assisted removal of osteochondral fragments was performed in all dogs with satisfactory short-term clinical outcome. NA is a feasible technique for diagnosis and lesion assessment in dogs with a fissured or fragmented coronoid process. Larger clinical studies with longer follow-up are necessary to validate the NanoScope operative arthroscopy system as an alternative strategy to SA for video-assisted treatment of medial coronoid disease.

Objective:  The objective of this prospective study was to evaluate the use of ultrasonography in the diagnosis of medial coronoid process disease in unclear cases., Study Design:  Fifteen elbows (on thirteen dogs) for which radiography and computed tomography did not lead to a clear diagnosis of medial coronoid process disease were included. On each elbow, ultrasonography was performed with a high frequency linear transducer (12-18Hz). Then, arthroscopic examination of the joint was performed by a surgeon who was unaware of ultrasonographic findings to confirm medial coronoid process disease., Results:  At least one ultrasonographic lesion was detected in 13 out of 15 elbows. The main reported ultrasonographic lesions were joint effusion (10/15 elbows) and an abnormal shape of the medial coronoid process (irregular, ill-defined or fragmented) (9/15)., Conclusion:  Ultrasonography can be a helpful additional diagnostic tool to confirm medial coronoid process disease of the elbow joint before performing arthroscopy in unclear cases. Further studies will be needed to evaluate the use of higher frequency transducers and determine if it could improve the diagnostic value of ultrasonography., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective: To develop and describe a minimally invasive, ultrasound-guided, percutaneous technique for the desmotomy of equine palmar/plantar annular ligaments (PALs) using a transecting thread., Study Design: Ex vivo study., Sample Population: Twenty-one normal equine distal limb specimens., Methods: Under ultrasonographic guidance, a surgical thread was percutaneously placed around the PAL through 2 skin punctures (proximal and distal) using a 18 gauge spinal needle in equine limbs (11 forelimbs, 10 hindlimbs) with normal PALs. The ligament was transected by a back-and-forth motion of the thread until the loop emerged from the proximal skin puncture site. Each specimen was dissected and assessed for completeness of transection and iatrogenic damage under direct visualization. Descriptive statistics were reported., Results: The PAL was completely transected in 17/21 limbs. The mean duration of the procedure was 16 minutes. Superficial needle puncture or subtle abrasion of the superficial digital flexor tendon was noticed in 4 limbs. No iatrogenic injury to other intrathecal structures was identified. After PAL division, the needle entry and exit points had a mean diameter of 1.2 and 1 mm, respectively., Conclusion: Desmotomy of normal PALs in equine limb specimens was performed effectively using the percutaneous thread-transecting technique with minimal iatrogenic damage to adjacent structures., Clinical Significance: Information from this study will allow refinement of the technique for use in equine clinical cases either in standing or anesthetized horses., (© 2023 American College of Veterinary Surgeons.)

Objectives: The aim of this study was to compare the approximate center of rotation in normal and diseased elbows in dogs., Study Design: Cross-sectional study SAMPLE POPULATION: Computer tomography scans of nine dogs with unilateral fragmented medial coronoid process (FMCP)., Methods: A board certified radiologist confirmed that each dog had unilateral FMCP, and a normal contralateral elbow. Digital 3D models of all elbow joints were uploaded into a surgical planning software package. Four axes approximating the center of rotation (COR) of elbow joints were generated using five geometric shapes based on subchondral topography of the humeral condyle radius and ulna. Images showing the locations where axes exited the medial and lateral cortex of the humeral condyle were captured and imported into a second software package, for measurement of distances between exit points and the origin of a system of axes., Results: In normal joints 20/27 (74%) axes exited the medial cortex, and 25/27 (93%) axes exited the lateral cortex cranial and distal to the medial and lateral epicondyles, respectively. In diseased joints 22/27 (81%) axes exited medial cortex and 19/27 (70%) axes exited the lateral cortex, caudal and distal to the medial and lateral epicondyles, respectively., Conclusion: Based on CT- derived geometry, the COR of elbow affected with FMCP was generally more caudal than normal., Clinical Significance: External landmarks approximating the location of the elbow COR are provided, and while not validated, may assist in planning, creation, and assessment of procedures for FMCP., (© 2022 American College of Veterinary Surgeons.)

Objective: To evaluate a double hemitenotomy (DHT) technique as an alternative to complete deep digital flexor (DDFT) tenotomy., Study Design: Experimental ex vivo study., Sample Population: Isolated DDFTs (n = 30) and cadaveric forelimbs (n = 16)., Methods: In part 1, 15 isolated DDFT pairs were used. Two hemitenotomies were created in 1 DDFT while the other served as reference. Monotonic tensile load was applied. Tendon lengthening, load reduction, and load at failure were recorded. In part 2, 16 cadaveric forelimb pairs were subjected to DHT followed by complete tenotomy (CT) under monotonic compressive load. Differences between DHT and controls were assessed with Wilcoxon signed rank tests or Friedman tests., Results: In isolated tendons and cadaveric forelimbs, DHT resulted in DDFT lengthening (median, +1.9 mm and + 3.05 mm) and load reduction (median, -16.7 and -11.2 kg). Less lengthening was achieved with DHT compared to CT (P = .008). Load reduction did not occur between DHT and CT was observed during compressive testing (P = 1). Load reduction following the first hemitenotomy incision was smaller when compared to the second (P = .022). Isolated DHT tendons failed at a tensile load of 195 kg, while no intact tendons failed (P = .0001)., Conclusion: Double hemitenotomy was comparable to CT in load reduction. It reduced tensile strength, but load at failure was similar or exceeded the estimated DDFT load at stance., Clinical Significance: Hemitenotomy may be a useful alternative for surgical management of horses with laminitis, but in vivo studies are needed to confirm these findings., (© 2022 American College of Veterinary Surgeons.)

Case History: Dogs (n = 6) suffering from elbow-associated lameness for a median of 3.5 (min 2, max 12) months duration requiring arthroscopic exploration according to imaging results were prospectively included in this study., Clinical Findings: Dogs that met the inclusion criteria were of various breeds with a median body weight of 18 (min 13.2, max 34.5) kg and median age at presentation of 11 (min 6, max 96) months. Results of imaging modalities (radiographs and/or computed tomography (CT)) were consistent with developmental elbow disease in all of the dogs., Arthroscopic Findings: Feasibility of the needle arthroscopy procedure was first assessed in a preliminary cadaveric study. Disease-free cadaveric forelimbs (n = 12) were collected from adult dogs (n = 6) euthanised for reasons unrelated to the present study. Elbow exploration was performed, beginning with needle arthroscopy (1 mm, 0° angle scope) followed by standard arthroscopy (2.4 mm, 30° angle scope) through a medial approach. The ease of introduction, range of motion and the quality of visualisation were assessed subjectively and the presence of iatrogenic introduction lesions and extent of field of vision (assessed by the number of anatomical structures visualised) were scored and statistically compared. Needle arthroscopy allowed inspection of all structures at risk for medial/caudal compartment disease in all joints considering the occasional need for multiple portals. In the clinical setting, elbow exploration was found to be similar to that in cadaver joints in 4/6 dogs. The lower quality of vision provided by needle arthroscopy was a limitation of the technique, and 2/6 clinical cases required conversion to standard arthroscopy for full visualisation of the joint. No introduction lesions were noted with needle arthroscopy in either the cadaveric or clinical studies., Conclusions and Clinical Relevance: Needle arthroscopy allowed safe visualisation of all of the structures of the medial and caudal compartment in disease-free cadaveric elbows, suggesting that needle arthroscopy is an appropriate technique for diagnosis and assessment of lesions of developmental elbow disease. However, the low quality of vision provided by the 1 mm scope, and the small diameter of the sleeve, which limited fluid inflow, combined with fragility of the device were major drawbacks that prevented consistent full exploration of the joint and detailed lesion assessment in clinical situations. Improvement of the device is thus necessary before use of the technique in clinical practice can be recommended., Abbreviations: CCD: Caudal compartment disease; CT: Computed tomography; DED: Developmental elbow disease; DJD: Degenerative joint disease; LCL: Lateral collateral ligament; LCP: Lateral coronoid process; LHC: Lateral part of the humeral condyle; MCD: Medial compartment disease; MCL: Medial collateral ligament; MCP: Medial coronoid process; MHC: Medial part of the humeral condyle; MRI: Magnetic resonance imaging.

Objective: This report evaluates the use of 4.5- and 5.5-mm cannulated drill bits for articular cartilage removal from the proximal interphalangeal joints of equine cadaver limbs., Animals: Limbs from 8 equine cadavers, all with normal proximal interphalangeal joints., Procedure: Proximal interphalangeal joints of 32 limbs from 8 equine cadavers were drilled using either 4.5- or 5.5-mm cannulated drill bits. Pastern joints were then disarticulated, and intra-articular drilling was evaluated by visual inspection., Results: Post-drilling evaluation revealed complete intra-articular drilling occurred in all 32 joints., Conclusion: Canulated 4.5- and 5.5-mm drill bits resulted in consistent accurate intra-articular drilling in the proximal interphalangeal joint of horses., Clinical Relevance: Cannulated drill bits provided an effective and consistent modality for articular cartilage removal with potential for improved accuracy of articular drilling and applications in minimally invasive proximal interphalangeal joint arthrodesis., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Objective: To identify prognostic factors for return to racing after lag screw repair of condylar fractures and develop a predictive model for return to racing., Study Design: Retrospective cohort study., Animals: A total of 356 horses referred to a single referral hospital in the UK with a third metacarpal/metatarsal condylar fracture between January 1999 and December 2018., Methods: Age, sex, fracture site, fracture characteristics, surgery related variables and complications were retrieved from case records. Data were divided into two sets for model training and model validation. Univariable analyses were performed, and predictors were selected in a stepwise fashion for inclusion in the multivariable logistic regression model. Sensitivity and specificity were evaluated using the second dataset., Results: Older horses, fillies, fractures of forelimbs, complex, complete, displaced or propagating fractures and concurrent proximal sesamoid bone fracture were negatively associated with return to racing. Colts and geldings were 3 and 4 times more likely to race than fillies, respectively. Horses with hindlimb, incomplete or nonpropagating fractures were 4, 5 and 4 times more likely to race than those with a forelimb, complete or propagating fracture, respectively. Using a predicted probability cut-off threshold of 0.5, a predictive model was created within one dataset (sensitivity = 84%, specificity = 50.5%) and applied to another (sensitivity = 83.1%, specificity = 24.0%)., Conclusion: Negative prognostic factors were identified and led to a predictive model with acceptable sensitivity and specificity in the tested population., Clinical Significance: The results provide proof of concept for the model in the reported population and justify further validation in different populations of horses., (© 2022 American College of Veterinary Surgeons.)

Objective: To report clinical experience using virtual surgical planning (VSP) and surgical application of 3D printed custom surgical guides to facilitate uni- and biapical correction of antebrachial deformities in dogs., Animals: 11 dogs (13 antebrachial deformity corrections)., Procedures: Using CT-based bone models, VSP was performed, and surgical guides were designed and 3D printed. The guides were used to execute osteotomies and align bone segments. Postoperative CTs were obtained to compare limb alignment with the VSP. Long-term assessment of lameness and cosmesis were compared with preoperative status., Results: Guides were successfully utilized and postoperative analysis was available for 10 of 13 deformities. Guides were abandoned in 2 deformities due to soft tissue tension. Evaluation of postoperative frontal, sagittal, axial, and translational limb alignment revealed that over 90% of parameters were within the acceptable range of ≤ 5° angulation and rotation or ≤ 5 mm of translation from the VSP. Lameness scores were improved in 7/8 deformities with associated preoperative lameness, and posture was improved in 10/10 deformities in which guides were deployed. Complications included reduced range of carpal motion (n = 2), implant sensitivity (n = 2), fracture (n = 1), and tendon laceration (n = 1)., Clinical Relevance: VSP and customized surgical guide application facilitated accurate antebrachial limb deformity correction in the majority of deformities in this case series. The use of VSP and 3D printed guides would appear to be a viable and accurate approach for correction of both uni- and biapical antebrachial deformities in dogs.

Background: Until recent years, arthroscopic subtotal coronoidectomy has been the universally accepted treatment for medial coronoid disease but has variable clinical outcomes. The aim of this study was to evaluate the completeness of arthroscopic medial coronoid debridement and to detect the most vulnerable location of failure., Methods: Eighty-three dogs with a diagnosis of medial coronoid disease were included in the study. Arthroscopic debridement was performed in 92 elbow joints, and the completeness of removal was assessed by postoperative computed tomography scans., Results: Pathological changes were confined to the coronoid apex in 92/92 (100%) of cases and combined with radial incisure lesions in 39/92 (42%). Apical lesions were completely removed in 66/92 (72%) of cases and radial incisure lesions in 2/39 (5%). Bony remnants were detected at the apex (46%) and base (24%) of the medial coronoid process, free within the elbow joint (9%), and/or within the instrument port (84%). Fissures were positively associated with the occurrence of bony remnants (p = 0.038) and a 37% higher probability of incomplete removal of radial incisure lesions (p = 0.001)., Conclusion: In this study, incomplete removal was more likely to occur in the presence of radial incisure lesions. Thorough assessment of this region during arthroscopy is strongly recommended., (© 2021 British Veterinary Association.)

Objective: To detail the qualitative fascial categories and fascial intersections of the forelimb of the dog to facilitate preoperative planning for superficial cancers., Study Design: Qualitative anatomical study., Sample Population: Three male and four female mixed breed canine cadavers weighing approximately 20-35 kg., Methods: The skin and subcutaneous fat were excised. Fascial planes were incised and elevated to allow exploration of their quality and borders. Fascia was categorized as type I (discrete sheets), type II (tightly adhered to thin muscles), type III (tightly adhered to thick muscles), or type IV (associated with periosteum). Photographs of specimens were digitally modified with overlays to map tissue types., Results: Differences between the cadavers used were largely based on muscle mass and sex, with minimal other subjective differences affecting fascial mapping. The fasciae of the forelimb were largely type II or type III, with type I fascia at the antebrachium and type IV fascia at the olecranon, scapular spine, and accessory carpal bone. Fascial integrity was often questionable or lacking distal to the distal quarter of the antebrachium., Conclusion: The fascial types and integrity of the forelimb varied with anatomic location with thin or absent fascia for surgical use at the elbow, carpus, and manus., Clinical Significance: This study provides information for preoperative planning and excision of superficial tumors of the forelimb. Knowledge of the potential limitations of fascia to provide a deep margin may influence selection of treatment modalities., (© 2021 American College of Veterinary Surgeons.)

Surgical nerve transfers are used to efficiently treat peripheral nerve injuries, neuromas, phantom limb pain, or improve bionic prosthetic control. Commonly, one donor nerve is transferred to one target muscle. However, the transfer of multiple nerves onto a single target muscle may increase the number of muscle signals for myoelectric prosthetic control and facilitate the treatment of multiple neuromas. Currently, no experimental models are available. This study describes a novel experimental model to investigate the neurophysiological effects of peripheral double nerve transfers to a common target muscle. In 62 male Sprague-Dawley rats, the ulnar nerve of the antebrachium alone (n=30) or together with the anterior interosseus nerve (n=32) was transferred to reinnervate the long head of the biceps brachii. Before neurotization, the motor branch to the biceps' long head was transected at the motor entry point. Twelve weeks after surgery, muscle response to neurotomy, behavioral testing, retrograde labeling, and structural analyses were performed to assess reinnervation. These analyses indicated that all nerves successfully reinnervated the target muscle. No aberrant reinnervation was observed by the originally innervating nerve. Our observations suggest a minimal burden for the animal with no signs of functional deficit in daily activities or auto-mutilation in both procedures. Furthermore, standard neurophysiological analyses for nerve and muscle regeneration were applicable. This newly developed nerve transfer model allows for the reliable and standardized investigation of neural and functional changes following the transfer of multiple donor nerves to one target muscle., Competing Interests: ML, JK, SM, JI, VT, CF, GL, OP, UM, DF, OA, KB No competing interests declared, (© 2021, Luft et al.)

Objective: To evaluate the diagnostic value of still images of needle arthroscopy (SNAR), still images of traditional arthroscopy (STAR), and computed tomography (CT) to diagnose medial coronoid process (MCP) pathology., Study Design: Prospective clinical trial., Animals: Dogs (n = 17) presented for evaluation of elbow dysplasia., Methods: For each case, two SNAR and STAR images of the MCP were reviewed independently and in random order by three board-certified surgeons. Computed tomographic images were reviewed by one board-certified radiologist. Reviewers were blinded to surgical and clinical findings. Surgical findings from real-time TAR with palpation were used as the gold standard. Receiver operating characteristic (ROC) curves and concordance statistics tests for the diagnostic accuracy of MCP fissure, MCP fragment, medial compartment condition, and cartilage score were calculated., Results: Images of 27 elbows joints were reviewed. For MCP fissure detection, areas under the ROC curves for CT (0.84), STAR (0.73), and SNAR (0.57) did not differ. For the detection of MCP fragment, STAR had a larger area under the ROC curve (0.93) compared with SNAR (0.74, P = .015) and CT (0.54, P < .001). Still images of TAR and SNAR had comparable concordance for cartilage score (0.80 and 0.77, respectively) and medial compartment pathology (0.80 and 0.73, respectively)., Conclusion: Still images of NAR, STAR, and CT had similar diagnostic value to identify MCP fissures. Still images of TAR was superior to SNAR and CT to identify MCP fragments., Clinical Significance: The diagnostic accuracy of SNAR varied on the basis of the coronoid lesion being evaluated., (© 2021 The American College of Veterinary Surgeons.)

The mechanisms underlying postoperative pain differ from the inflammatory or neuropathic pain. Previous studies have demonstrated that intrathecal α-amino-3-hydroxy-5-methy-4-isoxazole propionate (AMPA) -kainate (KA) receptor antagonist inhibits the guarding pain behavior and mechanical hyperalgesia, indicating a critical role of spinal KA receptors in postoperative pain hypersensitivity. However, how the functional regulations of spinal KA receptor subunits are involved in the postoperative pain hypersensitivity remains elusive. Therefore, in the current study, we investigated the synaptic delivery of spinal KA receptor subunits and the interaction between KA receptor subunits and glutamate receptor-interacting protein (GRIP) during the postoperative pain. Our data indicated that plantar incision induced the synaptic delivery of GluK2, but not GluK1 or GluK3 in ipsilateral spinal cord dorsal horns. The co-immunoprecipitation showed an increased GluK2 -GRIP interaction in ipsilateral dorsal horn neurons at 6 h post-incision. Interestingly, Intrathecal pretreatment of GRIP siRNA increased the paw withdrawal thresholds to mechanical stimuli and decreased the cumulative pain scores in the paws ipsilateral to the incision at 6 h post-incision. Additionally, Intrathecal pretreatment of GRIP siRNA reduced the synaptic abundance of GluK2 in ipsilateral spinal dorsal horn at 6 h after plantar incision. In general, our data have demonstrated that the GluK2- GRIP interaction-mediated synaptic abundance of GluK2 in dorsal horn neurons plays an important role in the postoperative pain hypersensitivity. Disrupting the GluK2- GRIP interaction may provide a new approach for relieving postoperative pain.

To evaluate the feasibility of performing needle arthroscopy of the scapulohumeral joint and bicipital bursa in standing horses by using the thoracic limbs of euthanized horses. To that purpose, this experimental study was designed. Ten thoracic limbs, five left and five right from euthanized horses were retained in an upright position to simulate a standing horse. The craniolateral and lateral scapulohumeral arthroscopic portals were used to access the articular structures. A third (caudal) portal was also identified and described. The degree of difficulty in accessing the articular space and the optic maneuverability within the joint were compared between portals. The needle arthroscopy image lacks in quality, but the procedure was considered useful as a diagnostic aid for examination of the scapulohumeral joint of horses. Needle arthroscopy of the bicipital bursa was not possible. Needle arthroscopy has a great diagnostic potential for lesions in the scapulohumeral joint of horses. A new access (caudal) to the scapulohumeral joint of horses has been identified., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: To assess suspensory ligament extensor branch location and fracture gap reduction with simulation of standing and recumbent cortical bone screw repair of experimental incomplete parasagittal proximal phalanx (P1) fractures., Study Design: Controlled laboratory study., Sample Population: Twenty equine cadaver forelimbs., Methods: Simulated fractures were repaired twice in random order. A proximal cortical bone screw was placed in lag fashion with the limb unloaded (simulated recumbent repair) and loaded to 38% of body weight (range, 375-568 kg; simulated standing repair). Changes in fracture gap width were assessed on computed tomography (CT) images and with intraplanar force-sensitive resistors measuring voltage ratios (V △ ) between loaded recumbent (R-1) and standing repair simulations (R-2). Extensor branch borders were determined relative to implant position and sagittal P1 width on transverse CT images. P ≤ .05 was considered significant., Results: Standing repair simulation-associated fracture gaps were not wider than in R-1 while controlling for confounding factors (loading weight, implant position, or animal age; P > .7, repeated-measures analysis of variance). Voltage ratio data associated with R-2 were not smaller than with R-1 (mean difference, 0.002 ± 0.052; one-sided Wilcoxon signed-rank test, P = .27). More of P1 width was approachable palmar to extensor branches when limbs were loaded (0.804 ± 0.314 cm) vs unloaded (0.651 ± 0.31 cm; paired Student's t test, P < .001)., Conclusion: Simulated standing repair was not associated with inferior fracture reduction compared with loaded simulations of recumbent repairs. Limb loading affected extensor branch location relevant to implant positioning., Clinical Significance: Unloading during standing repair of incomplete parasagittal proximal P1 fractures may not be required to optimize fracture reduction., (© 2021 The American College of Veterinary Surgeons.)

Several juvenile diseases affect the canine forelimb. The most common are hypertrophic osteodystrophy, panosteitis, and retained cartilaginous core. Panosteitis and hypertrophic osteodystrophy tend to be self-limiting, with a good long-term prognosis, although severe cases can develop. These diseases may recur during growth. Severe cases of hypertrophic osteodystrophy can lead to angular limb deformities and may even be fatal. Retained cartilaginous cores can be benign with no evidence of clinical signs and be found incidentally on radiographs. However, if they disrupt the distal ulnar physis, angular limb deformities may persist requiring surgical intervention with a corrective osteotomy., Competing Interests: Disclosure The author has no conflicts of interest to disclose in regard to this article., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Physeal injuries are common in the developing small animal and can result in growth disturbances of the forelimb. Resulting deformities can include limb shortening, joint incongruity, angulation, and alterations in joint loading with subsequent osteoarthritis, remodeling, and debilitation. Because of the unique paired bone configuration, the antebrachium is the main source for malalignment resulting from physeal disturbance in the forelimb. Successful correction of deformities requires in-depth understanding of normal physeal activity; careful consideration of patient signalment; and the ability to quantify the location, magnitude, and plane of the deformity or deformities., Competing Interests: Disclosure The author has no commercial or financial interests associated with any of the information provided in this article., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Pancarpal arthrodesis is purported to limit supination and pronation of the feline antebrachium. The objective of this study was to investigate whether plate fixation of the radius to the carpus and metacarpus limits supination and pronation of the ulna relative to the radius as a model for pancarpal arthrodesis in the cat. Eight feline cadaveric forelimbs were rotated from supination to pronation in a testing jig and CT (computed tomography) was performed in the neutral, supinated and pronated positions. A locking plate was then secured dorsally to the radius, radial carpal bone and metacarpal III of each of the limbs. CT was repeated in each of the testing positions following plate application. The radius and ulna of the control specimens, and the radius, ulna and plate of the plated specimens were then segmented using software. Alignment of the bones to the radius in the control specimens, and to the plate in the plated specimens was used to compare the changes in degrees of movement of the ulna relative to the radius in dorsal, sagittal and transverse planes., Results: Based on the results of the paired t test, there was no significant difference in degrees of movement, or total range of motion between control and plated specimens in supinated and pronated testing conditions., Conclusion: The results of this ex-vivo study indicate that under the testing conditions employed, plate fixation of the radius to the carpus and metacarpus does not limit supination and pronation of the feline antebrachium.

The objectives of this in vivo experimental study were to evaluate the feasibility of cortical screw insertion into the intact distal phalanx in standing sedated horses and to document potential postoperative complications. One cortical screw was randomly inserted in lag fashion into each distal phalanx in 9 horses. The second surgery on the contralateral limbs was performed 2-3 weeks after the first operation, when a 4.5-mm cortical screw was inserted in lag fashion into the distal phalanx of sedated horses following perineural analgesia. Following surgery, the drill hole was filled with an antibiotic-soaked swab, which was changed every 48 h. The horses were euthanised 8 weeks after the second surgery. The hooves were disarticulated and evaluated macroscopically and by computed tomography. The surgery time was 13.9 ± 4.8 min (mean ± SD). Pain scores and lameness gradually decreased after 7 days. Solar canal penetration (SCP) was detected in 10 out of the 18 distal phalanges (55.5%). In 7 out of the 10 penetrations intraoperative bleeding was obvious. No postoperative infection was observed. Screw insertion into the distal phalanx was easily and quickly accomplished in standing horses, but its advantages in horses with sagittal fractures should be investigated further. SCP had no impact on postoperative lameness.

Objective:  The aim of this study was to evaluate the surgical execution of a virtual surgical plan (VSP) with three-dimensional (3D) guides against a freehand approach in the equine navicular bone using an automated in silico computer analysis technique., Study Design:  Eight pairs of cadaveric forelimb specimens of adult horses were used in an ex vivo experimental study design with in silico modelling. Limbs received either a 3.5 mm cortical screw according to a VSP or using an aiming device. Using computed tomography and computer segmentation, a comparison was made between the executed screw and the planned screw using the Hausdorff distance (HD)., Results:  Navicular bone mean HD registration error was -0.06 ± 0.29 mm. The VSP with 3D printing demonstrated significantly superior accuracy with a mean deviation of 1.19 ± 0.42 mm compared with aiming device group (3.53 ± 1.24 mm, p  = 0.0018). The VSP group was 5.0 times more likely to result in a mean aberration of less than 1.0 mm (95% confidence interval, 0.62-33.4). A 3.5 mm screw with an optimal entry point can have a maximum deviation angle of 3.23 ± 0.07, 2.70 ± 0.06 and 2.37 ± 0.10 degrees in a proximal, dorsal and palmar direction respectively, prior to violating one of the cortical surfaces., Conclusion:  Procedures performed using the 3D guides have a high degree of accuracy, with minimal mean deviations (<1 mm and <1 degree) of a VSP compared with those using the conventional aiming device. The use of VSP and the HD for evaluation of orthopaedic surgeries and outcome measures shows promise for simplifying and improving surgical accuracy., Competing Interests: None declared., (Thieme. All rights reserved.)

Transplantation of vascularized composite allografts (VCAs) provides a means of restoring complex anatomical and functional units following burns and other disfigurement otherwise not amenable to conventional autologous reconstructive surgery. While short- to intermediate-term VCA survival is largely dependent on patient compliance with medication, the myriad of side effects resulting from lifelong systemic immunosuppression continue to pose a significant challenge. Topical immunosuppression is therefore a logical and attractive alternative for VCA. Current formulations are limited though, by poor skin penetration but this may be mitigated by conjugation of immunosuppressive drugs to TyroSpheres for enhanced delivery. Therefore, we investigated the topical application of FK506-TyroSpheres (in the form of a gel dressing) in a clinically relevant nonhuman primate VCA model to determine if allograft survival could be prolonged at reduced levels of maintenance systemic immunosuppression. Six Major Histocompatibility Complex (MHC)-mismatched cynomolgus macaques (Macaca fascicularis) served as reciprocal donors and recipients of radial forearm fasciocutaneous flaps. Standard Bacitracin ointment and FK506-TyroSpheres were applied every other day to the VCAs of animals in groups 1 (controls, n = 2) and 2 (experimental, n = 4), respectively, before gradual taper of systemic FK506. Clinical features of VCA rejection still developed when systemic FK506 fell below 10 ng/ml despite application of FK506-TyroSpheres and prolonged VCA survival was not achieved. However, unwanted systemic FK506 absorption was avoided with TyroSphere technology. Further refinement to optimize local drug delivery profiles to achieve and maintain therapeutic delivery of FK506 with TyroSpheres is underway, leveraging significant experience in controlled drug delivery to mitigate acute rejection of VCAs., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Burn Association. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

An 8 yr old male castrated hound presented for a left distal ulnar osteosarcoma. Staging (computed tomography and nuclear scintigraphy) did not reveal any metastases. A limb-sparing ulnectomy with local adjunctive carboplatin in a poloxamer copolymer gel (poloxamer 407) was performed. The patient recovered without complications after surgery. No wound healing complications or adverse effects occurred after local use of carboplatin in poloxamer 407. The local recurrence-free interval was 296 days from surgery, and the survival time was 445 days from initial diagnosis. This is the first report in the veterinary literature of using poloxamer 407 as a carrier for local delivery of chemotherapeutic drugs in a clinical patient., (© 2020 by American Animal Hospital Association.)

Amputation surgery in pinniped rehabilitation centers is a feasible procedure when animals are presented with open fractures, osteomyelitis, and/or infectious arthritis of the flippers that appear to be refractory to medical treatment. From 2011 to 2017, the Sealcentre Pieterburen in The Netherlands admitted 3,775 seals for rehabilitation. Of these, 37 individuals presented clinical and radiologic signs of bone abnormalities indicative of osteomyelitis or infectious arthritis refractory to medical treatment. Seven cases resulted in euthanasia, and 30 cases underwent amputation surgery. The surgical procedure involved amputation of part of a flipper (24; two animals twice) or of a complete flipper (eight). All procedures were done under general anesthesia except one that was performed with local anesthesia, and all 30 animals were released. In two cases, the osteomyelitis presented with the rare Totenlade phenomenon, a sequestrum surrounded by new periosteal bone formation. The purpose of this retrospective study was to evaluate the outcome of the operative treatment of osteomyelitis and infectious arthritis in the flippers of harbor ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) during this 6-yr period.

This study aimed to evaluate the transection of superficial digital flexor tendon (SDFT) and deep digital flexor tendon (DDFT) in calves with severe metacarpophalangeal flexural deformities (MPFD). The study comprised 17 forelimbs of 10 calves that were diagnosed at the Animal Medical Centre, Rakuno Gakuen University. The calves were treated via transection of the SDFT and DDFT with retention of the suspensory ligament, followed by external fixation according to a post-surgical gait test. The post-procedural prognosis was determined at 14 days post-surgery. Of the 17 limbs, 14 (82%) achieved non-lameness and a good prognosis. Surgical complications were not observed in any treated calves. The transection of SDFT and DDFT is an effective first-line surgical option for calves with severe MPFD.

Objective: To determine the influence of a purpose-built frame on the accuracy of screw placement during computer-assisted orthopedic surgery (CAOS) of the equine extremity., Study Design: Experimental cadaveric study., Sample Population: Twenty-four paired equine cadaveric limbs obtained from seven horses., Methods: Three 4.5-mm cortex screws were inserted in lag technique in three different planes of orientation in the proximal phalanx (P1) by means of CAOS. In the study group (n = 12 limbs), the tracker was anchored on a purpose-built frame designed to stabilize the extremity. In the control group (n = 12 limbs), a conventional tracker array was used that was anchored directly on P1. The stability of both tracker arrays was assessed during the procedure by using fiducial markers. After screw placement, preoperative and postoperative computed tomographic images were assessed to measure surgical accuracy aberrations (SAA) between the planned and achieved screw position. Descriptive statistics and repeated-measures analysis of variance were performed to compare SAA measurements between the study and control group., Results: Both tracker arrays remained consistently stable in all specimens. Mean overall SAA of screw insertion were lower in the study group (0.7 mm; median, 0.5; range 0-3.4) than in the control group (1.2 mm; median, 0.9; range, 0-4.2 mm)., Conclusion: The mean SAA achieved in cortex screw placement using CAOS lies within the range of approximately 1 mm. The use of a purpose-built frame avoided additional drilling of the target bone and improved surgical accuracy compared with the conventional tracker array., Clinical Significance: The purpose-built frame described in this report can be used to facilitate CAOS in equine orthopedics without compromising surgical accuracy., (© 2020 The American College of Veterinary Surgeons.)

Objective: To determine the effect of proximal abducting ulnar osteotomy (PAUL) on frontal plane thoracic limb alignment in standing and recumbent positions., Study Design: Ex vivo cadaveric study., Sample Population: Canine thoracic limbs (n = 15 limb pairs)., Methods: Limbs were acquired from healthy Labrador retrievers that had been euthanized for reasons unrelated to this study. A limb press was used to obtain standing and recumbent caudocranial radiographs before and after PAUL. Foot lateralization and rotation were directly measured in standing position. Mechanical joint angles were determined using full limb radiographic montages and the center of rotation of angulation (CORA) method for pre-PAUL (Pre), 2-mm PAUL (PAUL2), and 3-mm PAUL (PAUL3). Data are reported as mean ± SD and 95% CI. Mixed linear modeling was used to identify differences in limb alignment values and foot position, with significance established at P ≤ .004., Results: There were differences in five of 12 limb alignment values pre-PAUL and post-PAUL in standing and recumbent positions. In the standing position, there was an increase in mechanical medial proximal radioulnar angle (Pre, 80.6° ± 2.5°; PAUL2, 82.6° ± 2.4°; PAUL3, 84° ± 2.4°) and a decrease in elbow compression angle (Pre, 1.4° ± 1.3°; PAUL2, 1° ± 0.9°; PAUL3, 0.8° ± 1°). There was a movement of mechanical humeral radioulnar angle (Pre, -8.9° ± 2.8°; PAUL2, -6.1° ± 2.7°; PAUL3, -5.2 ± 2.7°), mechanical thoracic humeral angle (Pre, 3.9° ± 1.7°; PAUL2, 2.4° ± 1.4°; PAUL3, 2.6° ± 1.5°), and elbow mechanical axis deviation (Pre, 1.9% ± 1.1%; PAUL2, 0.9% ± 1.1%; PAUL3, 0.4% ± 1.4%) toward a value of "0" representing coaxial alignment of the limb. The foot underwent lateralization (Pre, 1.4 ± 0.6 cm; PAUL2, 1.8 ± 0.7 cm; PAUL3, 2.3 ± 0.7 cm) and external rotation (Pre, 10.5° ± 4.7°; PAUL2, 13.7° ± 5.1°; PAUL3, 16° ± 6.6°)., Conclusion: In the ex vivo setting, PAUL resulted in translation of the mechanical axis of the thoracic limb from a medial to lateral direction through alterations in limb alignment values associated with the elbow, humerus, and proximal radius/ulna., Clinical Significance: Additional studies are required to determine whether PAUL alters thoracic limb alignment in client-owned dogs., (© 2020 The American College of Veterinary Surgeons.)

Ischemia and reperfusion injury remains a significant limiting factor for the successful revascularization of amputated extremities. Ex vivo normothermic perfusion is a novel approach to prolong the viability of the amputated limbs by maintaining physiologic cellular metabolism. This study aimed to evaluate the outcomes of extended ex vivo normothermic limb perfusion (EVNLP) in preserving the viability of amputated limbs for over 24 hours. A total of 10 porcine forelimbs underwent EVNLP. Limbs were perfused using an oxygenated colloid solution at 38°C containing washed RBCs. Five forelimbs (Group A) were perfused for 12 hours and the following 5 (Group B) until the vascular resistance increased. Contralateral forelimbs in each group were preserved at 4°C as a cold storage control group. Limb viability was compared between the 2 groups through assessment of muscle contractility, compartment pressure, tissue oxygen saturation, indocyanine green (ICG) angiography and thermography. EVNLP was performed for 12 hours in group A and up to 44 hours (24-44 hours) in group B. The final weight increase (-1.28 ± 8.59% vs. 7.28 ± 15.05%, P = .548) and compartment pressure (16.50 ± 8.60 vs. 24.00 ± 9.10) (P = .151) were not significantly different between the two groups. Final myoglobin and CK mean values in group A and B were: 875.0 ± 325.8 ng/mL (A) versus 1133.8 ± 537.7 ng/mL (B) (P = .056) and 53 344.0 ± 16 603.0 U/L versus 64 333.3 ± 32 481.8 U/L (P = .286). Tissue oxygen saturation was stable until the end in both groups. Infra-red thermography and ICG-angiography detected variations of peripheral limb perfusion. Our results suggest that extended normothermic preservation of amputated limbs is feasible and that the outcomes of prolonged EVNLP (>24 hours) are not significantly different from short EVNLP (12 hours)., (© 2020 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.)

Objective: To describe clinical applications of computer-assisted orthopedic surgery (CAOS) in horses with a navigation system coupled with a cone beam computed tomography unit., Study Design: Retrospective clinical case series., Animals: Thirteen adult horses surgically treated with CAOS., Methods: Medical records were searched for horses that underwent CAOS between 2016 and 2019. Data retrieved included signalment, diagnosis, lameness grade prior to surgery, surgical technique and complications, anesthesia and surgery time, and information pertaining to the perioperative case management and outcome., Results: In 10 cases, surgical implants were placed in the proximal phalanx, third metatarsal bone, ulna, or medial femoral condyle. In one case, navigated transarticular drilling was performed to promote ankylosis of the distal tarsal joints. In another case, an articular fragment of the middle phalanx was removed with the help of CAOS guidance. In the final case, a focal osteolytic lesion of the calcaneal tuber was curetted with the aid of CAOS. In seven cases, a purpose-built frame was used for the surgical procedure. All surgeries were performed successfully and according to the preoperative plan., Conclusion: Computer-assisted orthopedic surgery can be an integral part of the clinical case management in equine surgery. To optimize workflow and time-efficiency, the authors recommend designating one team for operative planning and another for the execution of the surgical plan. Specialized equipment, such as the purpose-built frame, will further improve CAOS applications in equine surgery., Clinical Significance: After they have become familiar with the operational principles, equine surgeons can readily apply CAOS for a broad spectrum of indications., (© 2020 The American College of Veterinary Surgeons.)

Objective: To determine the effect of surgery on lymphoscintigraphy drainage patterns from the canine brachium., Study Design: Experimental study., Animals: Eight healthy research beagles., Methods: A predefined area of skin measuring 2 × 1.5 cm in dimension was designated on either the right or left brachium. Preoperative lymphoscintigraphy was performed with technetium sulfur colloid injected into the subcutaneous tissues around the predefined anatomic location in a four-quadrant technique. Dogs underwent surgery for excision of the predefined area of skin, subcutis, and fascia of the lateral head of the triceps muscle with 1-cm margins. Eighteen days after surgery, lymphoscintigraphy was again performed with technetium sulfur colloid injected into the subcutaneous tissues around the surgical scar in a four-quadrant technique., Results: Sentinel lymph nodes were identified in eight of eight dogs preoperatively and in eight of eight dogs postoperatively. Agreement between the results of the preoperative and postoperative lymphoscintigraphy studies was identified as complete in four of eight dogs and partial in four of eight dogs. Sentinel lymph node identification occurred immediately in three of eight dogs preoperatively and in eight of eight dogs postoperatively., Conclusion: Sentinel lymph node identification occurred faster postoperatively. Agreement or partial agreement between the results of the preoperative and postoperative lymphoscintigraphy studies was observed in eight of eight dogs., Clinical Significance: Surgery appears to have an effect on lymphoscintigraphy drainage patterns. Additional studies are required to compare preoperative and postoperative sentinel lymph node mapping patterns in tumor-bearing dogs. However, this study provides preliminary information regarding the effect of surgery on sentinel lymph node identification., (© 2020 The American College of Veterinary Surgeons.)