Introduction
A 3-year-old 5-kg sexually intact female silvery langur (Trachypithecus cristatus) housed in a single-species group at a zoological institution was evaluated because of acute trauma to the left forelimb. Trauma was sustained when the langur’s forearm became trapped in the mesh of the enclosure, and the animal pulled the limb back while turning, thereby exerting torque and traction on the limb. The langur was placed in a squeeze cage, and anesthesia was induced with IM administration of medetomidine (0.12 mg/kg) and ketamine (7 mg/kg), after which an IV catheter was placed in the left saphenous vein. Radiography revealed a type II Monteggia fracture (Figure 1). Initial attempts at closed reduction of the fracture failed, and the elbow joint was immobilized with a modified Robert Jones bandage. Pain control was provided initially with meloxicam (0.2 mg/kg, SC, once daily as needed) and long-acting buprenorphine (Simbadol; Zoetis Inc; 0.2 mg/kg, SC, every 5 days for 2 doses). A modified Robert Jones bandage was placed on the left hind limb to protect the IV catheter. Surgical correction of the fracture was performed 4 days later.
The langur was placed in a squeeze cage and was administered maropitant (1.2 mg/kg, IV) 10 minutes prior to induction of anesthesia. Propofol (5.6 mg/kg, IV) was administered IV, and the patient was then moved into a kennel for transportation to the referral hospital. Upon arrival, medetomidine (0.03 mg/kg, IV) and 2 boluses of ketamine (4.8 mg/kg, each IV) were administered. The animal was intubated with a 3.5-mm endotracheal tube. Anesthesia was maintained with 0.8% to 2% inhaled isoflurane in 100% oxygen and propofol titrated IV to effect. The langur received intraoperative fluid therapy with balanced isotonic crystalloids (5 mL/kg/h, IV). Intraoperative hypotension was managed with constant rate infusions of lidocaine and phenylephrine as well as 2 IV fluid boluses (72 mL/kg). The patient received ampicillin sulbactam (36 mg/kg) 30 minutes prior to surgery and every 90 minutes during surgery.
Manipulation of the left elbow joint revealed severe instability; the radial head could be luxated both cranially and caudally. The langur was positioned in right lateral recumbency with a hanging left forelimb technique. A lateral approach to the left elbow joint and proximal portion of the antebrachium was made. Briefly, a skin incision was made over the lateral condyle of the humerus. The antebrachial fascia was incised to expose the triceps brachii, traumatized anconeus, and extensor carpi ulnaris muscles, which were retracted to expose the elbow joint. No remnant of the lateral collateral ligament was identified. Although not directly observed, the medial collateral ligament was palpably intact. The radius and ulna were craniomedially displaced with disruption of the annular ligament that resulted in radioulnar separation. Extension of the elbow joint, internal rotation of the carpus, and pronation of the limb allowed reduction of the humeroulnar luxation, but attempts to bring the radius into reduction while maintaining ulnar reduction were initially unsuccessful. The proximal ulnar fracture was therefore reduced and stabilized with a 5-hole, 2.0-mm locking compression plate and five 2.0-mm locking screws applied to the caudolateral aspect of the ulna. Once the ulnar fracture was stabilized, the radius was held in reduction to the ulna with point-to-point bone-holding forceps while a 1.5-mm positional screw was placed (Figure 1). Hemostasis was achieved with monopolar electrocautery. Pronation and supination of the antebrachium is important for arboreal primates, and this motion is eliminated by the placement of a radioulnar screw. However, such screw placement was unavoidable in this langur owing to the degree of elbow joint instability; therefore, a temporary positional screw was placed with anticipated removal after healing.
Because the lateral collateral ligament could not be reconstructed, a prosthetic lateral collateral ligament was implanted. The tendon of the origin of the extensor carpi radialis muscle was sharply transected, and a 2.8-mm screw-in suture anchor (FASTak II; Arthrex Inc) with high-strength braided synthetic suture material (#2 FiberWire; Arthrex Inc) was placed under fluoroscopic guidance within the lateral part of the humeral condyle at the origin of the lateral collateral ligament. A 1.5-mm screw and smooth washer were placed in the proximal lateral portion of the radial head. The suture material was tied under the screw head and washer in a figure-of-eight pattern to provide lateral joint stabilization, and the screw and washer were tightened to the bone (Figure 1).
The elbow joint was maneuvered through full range of motion smoothly and without luxation. The tendon of the extensor carpi radialis was reapposed with 2-0 polydioxanone suture (PDS II; Ethicon Inc) in a cruciate pattern. The muscular fascia was reapposed with 2-0 polydioxanone suture (PDS II; Ethicon Inc) in a cruciate pattern. A temporary hinged type 1A external skeletal fixator was placed along the lateral aspect of the humerus and radius with 100-mm hybrid connecting bars and one 1/16-inch and three 3/32-inch interface pins (Figure 2). The hinge was left unlocked to allow flexion and extension of the elbow joint. The subcutaneous tissue was closed with 3-0 polydioxanone suture (PDS II; Ethicon Inc) in a simple interrupted and cruciate pattern, the dermis was closed with 3-0 poliglecaprone-25 suture (Monocryl; Ethicon Inc) in a continuous intradermal pattern, and the skin was closed with 3-0 fluorescent monofilament polypropylene suture (Propylglo Green; Covetrus) in a simple interrupted pattern.
Because silvery langurs are highly social animals, this animal could not be separated from its troop during the recovery period. Prolonged isolation could lead to the development of stereotypical behaviors or ostracization following reintroduction.1 However, in group housing, damage to the patient’s external skeletal fixator by conspecifics was a concern. A modified Robert Jones bandage was applied over the patient’s entire left forelimb to cover the external skeletal fixator; subsequently, the bandage was covered with elastic tape to prevent self-trauma.
In the immediate postoperative period, the langur was hospitalized in a small enclosure for 9 days. During that time, an IV catheter in the tail vein was maintained and was replaced every 3 to 6 days, at times that coincided with anesthesia of the langur for bandage changes and passive range-of-motion exercises. During hospitalization, anesthesia of the langur was performed with IV administration of medetomidine and ketamine with or without propofol. The langur was subsequently transitioned to an enclosure with a small conspecific subgroup. At that time, conspecifics attempted to manipulate the external skeletal fixator and bandage; therefore, subsequent bandages applications incorporated a thin layer of casting material (Vetcast Plus Veterinary Casting Tape; 3M Healthcare) to prevent damage by conspecifics. To facilitate bandage changes, the langur underwent squeeze cage restraint and was anesthetized with IM injection of dexmedetomidine and ketamine every 2 to 7 days.
While the langur was anesthetized, pin insertion sites were cleaned and passive range-of-motion exercises were performed. Elbow joint range of motion was markedly limited to a total range of 15° (flexion, 110°; extension, 135°) in the postoperative period secondary to bandage immobilization in combination with slight displacement of the external skeletal fixator hinge from the elbow joint. Notable peri-incisional dermatitis and pin insertion site dermatitis developed in the postoperative period, including ulceration and pitting edema, and were managed by treatment with ceftiofur crystalline free acid (20 mg/kg, SC, q 7 days for 4 doses) followed by trimethoprim sulfamethoxazole (20 mg/kg, PO, once daily for 2 weeks). Inflammation and potential discomfort were managed with meloxicam (0.1 mg/kg, PO, once daily for 30 days) and tramadol (2 mg/kg, PO, twice daily for 10 days) administration.
Approximately 4 weeks after surgery, the external skeletal fixator was removed, and the left forelimb limb was maintained in a modified Robert Jones bandage for 2 weeks. Six weeks after surgery, the langur was anesthetized and the radioulnar positional screw was removed. Briefly, the head of the screw was palpated at the lateral aspect of the proximal portion of the ulna. A stab incision was made over the head of the screw, and the screw was removed. The incision was closed with 3-0 poliglecaprone-25 suture (Monocryl; Ethicon Inc) in a simple interrupted pattern in the subcutaneous tissue and a buried interrupted pattern in the dermis. There was no instability in the elbow joint following positional screw removal. At that time, the elbow joint had minimal range of motion. The langur underwent behavioral training to reach for and grip objects in exchange for strongly appealing food items, as a form of physical therapy to improve range of motion of the left elbow. The langur showed noticeable improvement in elbow joint range of motion and activity within 2 months after surgery and returned to normal unrestricted activity with full range of motion of the elbow joint at 3 months after surgery.
Discussion
Silvery langurs (Trachypithecus cristatus) are Old World arboreal folivorous (colobine) monkeys native to coastal forests of Borneo, Malaysia, and Sumatra in Southeast Asia.2 The silvery langur is a semibrachiator that uses its forelimbs to suspend and propel its body and also performs quadrupedal climbing, leaping, and jumping.3,4 In captivity, brachiation is common among juvenile silvery langurs, but it is seldom to never observed among adults.5,6 Trauma is common in captive silvery langurs, particularly among infants and juveniles.7
Elbow joint luxation is the second most common type of joint dislocation in human adults and the most common type in human children8 but has been infrequently reported for captive and free-ranging primates.9,10,11 Prolonged immobilization is often successful in managing elbow joint dislocation and disruption of the lateral collateral ligament in children.8,12 Radioulnar luxation in a bonnet macaque (Macaca radiata) was successfully managed with closed reduction and subsequent immobilization of the limb in a cast.11 In the case described in the present report, cast immobilization alone was considered insufficient because of the severity of the joint instability and annular ligament disruption in this animal. Application of a hinged external skeletal fixator allowed for increased rigidity at the fracture repair site, reduction of supination and pronation, and improved rotational stability, compared with the effects of a cast. The hinged external skeletal fixator also allowed for the maintenance of reduction during passive range of motion of the elbow joint. In human adolescents and adults, hinged external skeletal fixation across the elbow joint has been suggested as a treatment of complex elbow dislocations with associated ligamentous injury owing to the potential for reduced range of motion associated with prolonged immobilization.12 For the langur of the present report, the hinged external skeletal fixator allowed a small degree of range of motion at the elbow joint, although further range of motion was limited by the presence of the bandage. Complications of prolonged postoperative immobilization include loss of range of motion of the joint, muscle atrophy, and cartilage atrophy.13 Even a small degree of joint movement, such as that provided by a hinged external skeletal fixator or flexibility of a cast, is protective against cartilage atrophy, resulting in less proteoglycan loss, compared with that associated with fully rigid external skeletal fixation.14
In humans, Monteggia fractures are often sustained following direct trauma to the ulna or a fall onto an outstretched hand while the forelimb is pronated or hyperextended.15 Early surgical repair is the standard of care in humans.15 Acute traumatic elbow joint luxation and mid-diaphyseal ulnar fracture in a common squirrel monkey (Saimiri sciureus) were successfully managed with suture repair of the lateral collateral ligament and placement of an external skeletal fixator.11 Use of prosthetic ligaments16,17 and autograft or allograft reconstruction of the lateral collateral ligament to address elbow joint luxation in humans have also been described.18,19,20 Acute traumatic lateral radial luxation and diaphyseal ulnar fracture with disruption of the lateral collateral ligament and annular ligament in a ring-tailed lemur was successfully managed with an intramedullary pin and a prosthetic lateral collateral ligament constructed from nonabsorbable suture.10
For collateral ligament repair in the langur of the present report, the braided synthetic suture material was selected because of its substantial strength, compared with that of other nonabsorbable suture mterial.21,22 The screw and washer technique has been applied in dogs and cats23,24 and in a ring-tailed lemur.10 This technique has the theoretical potential for failure of the braided material secondary to being cut by the screw threads, although in the authors’ experience, this technique is successful for collateral ligament repair. A method that incorporates bone tunnels for passage of the braided synthetic suture material in domestic species has also been described25,26; this method was considered for use in the langur but was elected against because of a concern that the braided, stiff material could result in the widening of bone tunnels with long-term use of a high-motion joint, which has been described in the human medical literature.27,28 The authors acknowledge that both surgical techniques have the potential for complications, including failure of the repair, soft tissue irritation, or the need for implant removal or revision surgery.
In the dogs and cats, traumatic elbow joint luxation is uncommon. This injury is most often sustained secondary to vehicular trauma.29 Early closed reduction with external coaptation is typically the first line of treatment and can have an excellent outcome if joint stability is achieved.29,30,31,32 Reluxation is the most frequent major complication and is more common when the joint remains unstable following reduction. Surgical stabilization is indicated in cases where closed reduction cannot be achieved, joint laxity persists following closed reduction, or reluxation occurs.29,30,31,32,33 In 16 dogs and 12 cats with a Monteggia fracture-luxation, open reduction and internal fixation were reported to be required in 89% of cases.34 Closed reduction and transarticular external skeletal fixation to treat elbow joint luxation in dogs and cats have also been reported.35,36,37,38 The choice of surgical stabilization as a second-line treatment complicates the comparison of outcome with that of closed reduction because surgical cases likely involve luxations that are more chronic, more unstable, or more severe. In dogs and cats with ulnar fractures, commonly used techniques include open reduction and internal fixation or open reduction and placement of an external skeletal fixator. Implantation of prosthetic ligaments is infrequently reported in the veterinary medical literature but has been used in the management of elbow joint luxations in dogs and cats.26,39,40
In the authors’ clinical experience, a canine or feline patient with the type of injury sustained by the langur of the present report and that underwent a similar surgical repair could be managed with a soft padded bandage for 1 week, followed by removal of the bandage and unlocking of the hinge to movement of the joint earlier in the healing process as well as facilitating passive range-of-motion exercises, thereby improving earlier return to function and range of motion of the joint. For those dogs and cats, daily sessions of physical therapy would be recommended to improve range of motion, encourage controlled bone loading, and promote fracture healing. Additionally, the authors would recommend activity restriction for a period of 6 to 8 weeks to protect the external skeletal fixator from damage and the limb from excessive force, which could result in reluxation or fracture.37
The postoperative management of captive primates is challenging because these animals have a high level of intelligence and a high degree of dexterity and flexibility, allowing them to damage or dismantle bandages or orthopedic devices and increasing the risk of implant failure, infection, malunion, or bandage-associated morbidity. For the langur of the present report, postoperative exercise restriction was not possible because the animal was group housed. The external skeletal fixator was covered with a bandage and a light layer of casting material for most of the postoperative period. This bandage conferred more rigidity for a period of time longer than that which would be preferred for a small animal patient, and it limited range of motion of the langur’s elbow joint; however, the bandage was necessary to protect the external skeletal fixator from damage and keep the patient from overusing the limb in the postoperative period.
Another important consideration regarding the use of hinged external skeletal fixators is that care must be taken to appropriately align the hinge directly over the joint; failure to do so can result in a binding effect in which the hinge inhibits the normal biomechanics of the joint and further limits the joint’s range of motion. In the case described in the present report, fluoroscopic guidance was used to guide external skeletal fixator placement. However, postoperative radiographic views showed very slight distal and cranial displacement of the external skeletal fixator in relation to the joint, which likely contributed to postoperative limitations in range of motion of the elbow joint in this patient. However, following removal of the bandage and external skeletal fixator and along with physical therapy sessions, the langur regained full normal range of motion of the elbow joint.
The case described in the present report has highlighted the successful surgical stabilization and postoperative management of an ulnar fracture and acute traumatic elbow joint luxation in a captive silvery langur. This fracture-luxation was complex because of the major ulnar and radial head separation and was successfully managed with a temporary radioulnar positional screw and permanent prosthetic lateral collateral ligament, with full return to function of the joint following the recovery period. The use of open reduction and internal fixation of an ulnar fracture and stabilization of an elbow joint luxation with external skeletal fixation and a prosthetic ligament may be beneficial in other nonhuman primates.
Acknowledgments
No third-party funding or support was received in connection with this study or the writing or publication of the manuscript. The authors declare that there were no conflicts of interest.
References
- 1. ↑
Vessey SH. Free-ranging rhesus monkeys: behavioural effects of removal, separation and reintroduction of group members. Behaviour. 1971;40(3-4):216–227.
- 2. ↑
Furuya Y. The social life of silvered leaf monkeys: Trachypithecus cristatus. Primates. 1961;3:41–60.
- 3. ↑
Harding LE. Trachypithecus cristatus (Primates: Cercopithecidae). Mamm Species. 2010;42(862):149–165.
- 4. ↑
Napier JR. Evolutionary aspects of primate locomotion. Am J Phys Anthropol. 1967;27(3):333–341.
- 5. ↑
Amarasinghe A, Botejue WMS, Harding LE. Social behaviours of captive Trachypithecus cristatus (Mammalia: Cercopithecidae) in the National Zoological Gardens of Sri Lanka. Taprobanica. 2011;1(1):66–73.
- 6. ↑
Eakins A. Ontogeny of positional behavior in captive silvered langurs (Trachypithecus cristatus). Senior honors thesis. The Ohio State University; 2010.
- 7. ↑
Shelmidine N, McAloose D, McCann C. Survival patterns and mortality in the North American population of silvered leaf monkeys (Trachypithecus cristatus): silvered leaf monkey life tables. Zoo Biol. 2013;32(2):177–188.
- 8. ↑
Hyvönen H, Korhonen L, Hannonen J, Serlo W, Sinikumpu J-J. Recent trends in children's elbow dislocation with or without a concomitant fracture. BMC Musculoskelet Disord. 2019;20(1):294. doi: 10.1186/s12891-019-2651-8
- 9. ↑
Karesh WB, Wallace RB, Painter RLE, et al. Immobilization and health assessment of free-ranging black spider monkeys (Ateles paniscus chamek). Am J Primatol. 1998;44(2):107–123.
- 10. ↑
Leclerc A, Greunz EM, Daude-Lagrave A. Surgical treatment of a type III Monteggia fracture in a ring-tailed lemur (Lemur catta). Rev Med Vet (Toulouse). 2014;165(11-12):313–317.
- 11. ↑
Wellehan JFX, Lafortune M, Heard DJ. Traumatic elbow luxation repair in a common squirrel monkey (Saimiri sciureus) and a bonnet macaque (Macaca radiata). J Zoo Wildl Med. 2004;35(2):197–202.
- 12. ↑
Lieber J, Zundel SM, Luithle T, Fuchs J, Kirschner H-J. Acute traumatic posterior elbow dislocation in children. J Pediatr Orthop B. 2012;21(5):474–481.
- 13. ↑
Millis DL. Responses of musculoskeletal tissues to disuse and remobilization. In: Millis D, Levine D, eds. Millis Canine Rehabilitation and Physical Therapy. 2nd ed. Saunders Elsevier; 2014:92–153.
- 14. ↑
Behrens F, Kraft EL, Oegema TR. Biochemical changes in articular cartilage after joint immobilization by casting or external fixation. J Orthop Res. 1989;7(3):335–343.
- 15. ↑
Sheehan SE, Dyer GS, Sodickson AD, Patel KI, Khurana B. Traumatic elbow injuries: what the orthopedic surgeon wants to know. Radiographics. 2013;33(3):869–888.
- 16. ↑
Ek ET, Wang KK. Arthroscopic repair of the lateral ulnar collateral ligament of the elbow using a knotless suture anchor. Arthrosc Tech. 2018;7(2):e77–e81.
- 17. ↑
Trofa DP, Lombardi JM, Noticewala MS, Ahmad CS. Ulnar collateral ligament repair with suture augmentation. Arthrosc Tech. 2017;7(1):e53–e56.
- 18. ↑
Camp CL, Sanchez-Sotelo J, Shields MN, O'Driscoll SW. Lateral ulnar collateral ligament reconstruction for posterolateral rotatory instability of the elbow. Arthrosc Tech. 2017;6(4):e1101–e1105.
- 19. ↑
Conti Mica M, Caekebeke P, van Riet R. Lateral collateral ligament injuries of the elbow—chronic posterolateral rotatory instability (PLRI). EFORT Open Rev. 2017;1(12):461–468.
- 20. ↑
King GJW, Dunning CE, Zarzour ZDS, Patterson SD, Johnson JA. Single-strand reconstruction of the lateral ulnar collateral ligament restores varus and posterolateral rotatory stability of the elbow. J Shoulder Elbow Surg. 2002;11(1):60–64.
- 21. ↑
Burgess R, Elder S, McLaughlin R, Constable P. In vitro biomechanical evaluation and comparison of FiberWire, FiberTape, OrthoFiber, and nylon leader line for potential use during extraarticular stabilization of canine cruciate deficient stifles. Vet Surg. 2010;39(2):208–215.
- 22. ↑
Rose ND, Goerke D, Evans RB, Conzemius MG. Mechanical testing of orthopedic suture material used for extra-articular stabilization of canine cruciate ligament-deficient stifles. Vet Surg. 2012;41(2):266–272.
- 23. ↑
Griffon DJ. Surgical diseases of the elbow. In: Tobias KM, Johnston SA, eds. Veterinary Surgery: Small Animal. Saunders Elsevier; 2011:724–730.
- 24. ↑
Johnson A, Dunning D. Stabilization of lateral elbow luxation. In: Atlas of Orthopedic Surgical Procedures of the Dog and Cat. Saunders Elsevier; 2005:18–21.
- 25. ↑
Campbell JR. Luxation and ligamentous injuries of the elbow of the dog. Vet Clin North Am. 1971;1(3):429–440.
- 26. ↑
Farrell M, Thomson DG, Carmichael S. Surgical management of traumatic elbow luxation in two cats using circumferential suture prostheses. Vet Comp Orthop Traumatol. 2009;22(1):66–69.
- 27. ↑
Storey P, Gadd RJ, Blundell C, Davies MB. Complications of suture button ankle syndesmosis stabilization with modifications of surgical technique. Foot Ankle Int. 2012;33(9):717–721.
- 28. ↑
Willmott HJ, Singh B, David LA. Outcome and complications of treatment of ankle diastasis with tightrope fixation. Injury. 2009;40(11):1204–1206.
- 29. ↑
Sajik D, Meeson RL, Kulendra N, et al. Multi-centre retrospective study of long-term outcomes following traumatic elbow luxation in 37 dogs. J Small Anim Pract. 2016;57(8):422–428.
- 30. ↑
O'Brien MG, Boudrieau RJ, Clark GN. Traumatic luxation of the cubital joint (elbow) in dogs: 44 cases (1978–1988). J Am Vet Med Assoc. 1992;201(11):1760–1765.
- 32. ↑
Williams H, Calvo I, Gaines A, et al. Multi-centre retrospective study of the long-term outcome following suspected traumatic elbow luxation in 32 cats. J Small Anim Pract. 2020;61(6):354–362.
- 33. ↑
Schaeffer IGF, Wolvenkamp P, Meij BP, Theijse LFH, Hazewinkel HAW. Traumatic luxation of the elbow in 31 dogs. Vet Comp Orthop Traumatol. 1992;12(1):33–39.
- 34. ↑
Schwarz PD, Schrader SC. Ulnar fracture and dislocation of the proximal radial epiphysis (Monteggia lesion) in the dog and cat: a review of 28 cases. J Am Vet Med Assoc. 1984;185(2):190–194.
- 35. ↑
Hamilton K, Langley-Hobbs S, Warren-Smith C, Parsons K. Caudal elbow luxation in a dog managed by temporary transarticular external skeletal fixation. Case Rep Vet Med. 2014;2014:498329. doi: 10.1155/2014/498329
- 36. ↑
Abrescia P, Cinti F, Pisani G. Traumatic caudal elbow luxation in two cats. Open Vet J. 2020;9(4):361–365.
- 37. ↑
Jaeger GH, Wosar MA, Marcellin-Little DJ, Lascelles DX. Use of hinged transarticular external fixation for adjunctive joint stabilization in dogs and cats: 14 cases (1999–2003). J Am Vet Med Assoc. 2005;227(4):586–591.
- 38. ↑
Vedrine B. Use of an elastic transarticular external fixator construct for immobilization of the elbow joint. Can Vet J. 2017;58(4):353–359.
- 39. ↑
McCartney W, Kiss K, McGovern F. Surgical stabilization as the primary treatment for traumatic luxation of the elbow joint in 10 dogs. Int J Appl Res Vet Med. 2010;8(2):97–100.
- 40. ↑
Vallone L, Schulz K. Repair of Monteggia fractures using an Arthrex Tightrope system and ulnar plating. Vet Surg. 2011;40(6):734–737.