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Asian Journal of Animal and Veterinary Advances 10 (11): 789-796, 2015ISSN 1683-9919 / DOI: 10.3923/ajava.2015.789.796© 2015 Academic Journals Inc.

Impact of Dimethyl Sulfoxide (DMSO) Combined with Corticosteroidon Repair of Fractures of the Proximal Phalanx in 14 Horses

Mohamed B. Mostafa, Ashraf M. Abu-Seida and Ahmed I. AbdelgalilDepartment of Surgery, Anesthesiology and Radiology, Faculty of Veterinary Medicine, Cairo University,P.O. Box 12211, Giza, Egypt

Corresponding Authors: Ashraf M. Abu-Seida, Department of Surgery, Anesthesiology and Radiology, Faculty of VeterinaryMedicine, Cairo University, P.O. Box 12211, Giza, Egypt

ABSTRACTThis study evaluates the impact of fetlock intra-articular and digital flexor tendon sheaths

intra-synovial injections of dimethyl sulfoxide (DMSO) combined with corticosteroid as conservativetreatment of mid-sagittal fractures of the proximal phalanx (P1) in horses. Fourteen horses withradiographically confirmed mid-sagittal fractures of P1 were recruited for this study. These horseswere treated with fetlock intra-articular and digital flexor tendon sheaths intra-synovial injectionsof 5 mL of 20% dimethyl sulfoxide combined with 100 mg hydrocortisone sodium succinate.Fiberglass cast was applied from the carpal joint and down to the hoof. Intravenousphenylbutazone was injected at a dose of 4.4 mg kgG1 for one week. The animal was kept for boxconfinement for 3-8 weeks. Lameness re-examination and follow up radiographs were performedfor each horse after 1, 2 and 3 months of treatment. All data were expressed as mean and standarddeviation. Horses with short and long incomplete mid-sagittal fractures showed clinicalimprovement in lameness after 10±1.5 and 18±3 days of treatment and returned to work after33±2.5 and 55±5.5 days of treatment. Out of four horses with complete mid-sagittal fracture, threeanimals showed clinical improvement in lameness and recovery after 35±4.7 and 85±4.5 daysof treatment. In conclusions, conservative treatment including; fetlock intra-articular andintra-synovial of deep digital flexor tendon sheaths injection of DMSO combined with corticosteroid,fiberglass cast and box confinement can reduce the healing time and minimize the degenerativejoint changes and healing callus in both incomplete and complete mid-sagittal fractures of theproximal phalanx in horses.

Key words: DMSO, horses, hydrocortisone, proximal phalanx, mid-sagittal fracture

INTRODUCTIONFractures of the proximal pharanx (P1) are frequently common bone injury of thoroughbred and

standard bred horses. Sagittal fracture is the most common fracture of the proximal phalanx.Mid-sagittal fractures were classified into short (less than 30 mm), long (greater than 30 mm) andproximal incomplete and complete fractures (Stashak, 2002; Bertone, 2004).

Longitudinal compression and a synchronous lateral to medial rotation or twisting of the P1in relation to the third metacarpal/metatarsal bones were the central etiological factors (Ellis et al.,1987). The increase in P1 principal compressive and shear bone strains associated with restrictedfoot slip indicate that alterations in foot:ground interaction may play a role in fracture occurrencein horses (Singer et al., 2015).

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The most common clinical signs of proximal phalangeal fractures were lameness, fetlock jointeffusion, pain with flexion and rotation of the phalanges and hematoma on the proximal dorsalcortex of the proximal phalanx (Stashak, 2002).

Beside the clinical findings, several diagnostic imaging techniques have been applied fordiagnosis of P1 fractures including; radiography, ultrasonography, computed tomography,arthroscopy and high-field or low-field magnetic resonance (Elce and Richardson, 2002;Dyson et al., 2011; Brunisholz et al., 2015).

Various modalities have been used for treatment of P1 fractures in horses depending upon thetype of fracture. In addition, each of these modalities has several advantages and disadvantages.The P1 fractures have been repaired either by conservative treatment (Smith and Wright, 2014)or surgical interventions including; neutralized bone plates (Tetens et al., 1997), lag screws(Dechant et al., 1998), arthroscopy (Elce and Richardson, 2002), transfixation casting (Lescun et al., 2007), a tapered-sleeve transcortical pin external skeletal fixation device(Nunamaker and Nash, 2008). The main disadvantages of the surgical repair of P1 fractures arethe expense, potential risks and complications associated with general anesthesia and surgery.Adverse outcome to return the horse to athletic function after treatment of non-comminuted P1fractures with conservative and surgical repair with lag screw fixation has been reported(Tetens et al., 1997; Stashak, 2002).

Dimethyl sulfoxide (DMSO) has a potent anti-inflammatory, anti-arthritic, anti-plateletaggregation, analgesic, anti-bacterial, antifungal properties as well as the ability to serve as a freeradical scavenger of free oxygen and hydroxyl radicals (Brayton, 1986). DMSO has been used aloneor mixed with corticosteroids in horses to reduce soft tissue swelling and inflammation after acutetrauma. In addition, DMSO promotes the absorption of corticosteroids and the effect ofcorticosteroid was increased 10 fold when DMSO was used as a carrier (Koller, 1976).

Due to the expense, potential risks and complications of general anesthesia and surgery, thepurpose of this study was to report the outcome of fetlock intra-articular and digital flexor tendonsheaths intra-synovial injections of DMSO combined with corticosteroid as conservative treatmentof mid-sagittal fractures of the proximal phalanx in horses.

MATERIALS AND METHODSThis study was conducted on 14 draught horses admitted to the surgery clinic at Faculty of

Veterinary Medicine, Cairo University, Egypt. All horses suffered from forelimb lameness, fetlock joint effusion and hematoma on the

proximal dorsal cortex of the proximal phalanx. Full case history was obtained and thoroughclinical examination was carried out for all horses. The examined horses were subjected to fetlockjoint flexion test. Fracture of proximal phalanx was suspected in all horses.

Plain radiographic examination was carried out in all examined horses with an X-ray machine(Fischer, Stuttgart, Germany). The radiographic setting factors were 55-60 kVp, 10 mA and 90 cmfocal spot film distance (FFD). Dorsopalmar and lateromedial views were taken in all cases.Dorsolateral palmomedial, dorsomedial palmolateral oblique views were taken when necessary.Fractures were diagnosed and identified as previously described (Markel and Richardson, 1985).Conservative treatment of P1 fractures included fetlock intra-articular and intra-synovial of deepdigital flexor tendon sheaths injections of 5 mL of 20% Dimethyl sulfoxide (DMSO®, Diamond Lab.,USA) combined with 100 mg hydrocortisone sodium succinate (Solu-Cortef®, EP1CO, Egypt).Fiberglass cast (Fiberglass cast®, Afri Medical Co., Egypt) was applied from the carpal joint and

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down to the hoof. Intravenous non steroidal anti-inflammatory, Phenylbutazone (Phenyloject®,ADWIA, Egypt) was injected at a dose of 4.4 mg kgG1 for one week. The animal was kept for boxconfinement for 3-8 weeks. Lameness re-examination and follow up radiographs were performedfor each horse after 1, 2 and 3 months of treatment.

Statistical analysis: All data were expressed as mean and standard deviation using SPSS-version20 (IBM Corporation, 2009, New York, USA).

RESULTSClinical and radiographic examinations revealed mid-sagittal fracture at the proximal phalanx

in all horses. The mean age and weight of affected horses were 5.2 years and 520 kg. The affectedanimals were 10 horses and 4 mares. All horses had a history of a single forelimb lameness for aperiod of 2-28 days prior to the examination (mean 14.5±0.5). Lameness appeared 24-48 h afterheavy exercise or fast work.

The clinical signs included forelimb lameness, little weight bearing on the affected limb, fetlockjoint effusion, hematoma and pain at the dorsal surface of the proximal phalanx. The clinicalexamination revealed lameness before and after flexion test of the fetlock joint.

Proximal phalanx fracture was recorded in either left (8 cases) or right forelimb (6 cases). Short incomplete mid-sagittal proximal phalanx fractures, long incomplete mid-sagittal proximalphalanx fracture and complete mid-sagittal proximal phalanx fractures were observed in 5, 5 and4 horses, respectively. A distinct fracture pattern with one (11 cases) or two subchondral fracturelines (3 cases) running parallel in close proximity to each other was identified.

The impact of conservative treatment of short and long incomplete and complete mid-sagittalfractures of proximal phalanx was favorable in 13 horses. Moreover, all recovered horses resumedfull service and returned to the intended use in short duration with minimal arthritic changes. Thelameness improved at walking and appeared during trot after 10±1.5 days in horses with shortincomplete mid-sagittal fractures (Fig.1a). These affected horses were recovered and returned toexercise and work after 33±2.5 days of treatment (Fig.1b).

Horses with incomplete long mid-sagittal fractures showed clinical improvement in lamenessafter 18±3 days of treatment and complete recovery after 55±5.5 days of treatment.

Complete mid-sagittal fractures of proximal phalanx extending through lateral cortex (2 cases)and proximal interphalangeal joint (2 cases) were diagnosed in four horses (Fig. 2a). All horses hadsynovial distensions of the palmar pouches of fetlock joint and synovial digital flexor tendonsheaths with non weight bearing.

Three horses showed clinical improvement in lameness 35±4.7 days after treatment andrecovery after 85±4.5 days after treatment (Fig. 2b).

One mare with old complete mid-sagittal fracture of proximal phalanx extending throughproximal inter-phalangeal joint (Fig. 3a) showed persistence lameness with no clinical andradiographic improvement after 12 weeks of treatment. Radiography displayed secondarydegenerative joint disease of the fetlock joint and osteophytes formation at the dorsal aspects of themetacarpal bone and proximal phalanx (Fig. 3b). Other complications including; weight bearinglaminitis and digital flexor tendinitis were also developed in the contra-lateral limb. The owner wasadvised to destroy this mare.

DISCUSSIONFractures of the proximal phalanx are one of the most common fractures of Thoroughbred

horses in training and limited details on the effective treatment have been published (Smith and

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Fig. 1(a-b): (a) Dorsopalmar radiographic view of a 4 year-old horse showing a short incompletesagittal fracture of the proximal phalanx (arrow) and (b) Dorsopalmar radiographicview of the same horse after 4 weeks of treatment showing the repair of fracture line(arrow)

Wright, 2014). The P1 is prone to mid-sagittal fracture and less commonly frontal planelongitudinal fractures due to heavy exercise (Bertone, 2004; O'Hare et al., 2013).

The mean age and weight of the affected animals were 5.2 years and 525 kg. These findingsdiffer from other study which recorded the mean age of 9.5 years and mean body weight of 574 kg(Brunisholz et al., 2015). This difference could be attributed to the breed of examined horses withP1 fractures.

As other orthopedic affections in horses (Mostafa et al., 2014a, b; Senna et al., 2015), diagnosticimaging tools including; radiography, Computed Tomography (CT), ultrasonography, arthroscopy,high-field and low-field magnetic resonance have been used for diagnosis of P1 fractures in horses(Dyson et al., 2011; Brunisholz et al., 2015). Horses included in this study on the basis of bothclinical and radiographic diagnosis of incomplete (short and long) or complete sagittal fracture ofproximal phalanx (P1). In this respect computed tomography is superior to radiography in bothidentifying the fracture and determining fracture size and location (Brunisholz et al., 2015).Moreover, high-field or low-field Magnetic Resonance (MR) imaging confirms the presence of afissure fracture or subchondral and trabecular bone trauma of the P1 (Dyson et al., 2011;Pownder et al., 2015).

All of the examined horses had single P1 fracture of the forelimb. In contrast, Brunisholz et al.(2015) reported fourteen forelimbs and 10 hind limbs with P1 fractures. This difference could be

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Asian J. Anim. Vet. Adv., 10 (11): 789-796, 2015

Fig. 2(a-b): (a) Dorsopalmar radiographic view of a 2-year-old horse showing complete mid-sagittalfracture of the proximal phalanx (arrows) and (b) Dorsopalmar radiographic view of thesame horse after 8 weeks of treatment showing healing of the distal part of fractureline and narrowing of the proximal part of fracture (arrow)

attributed to the total number of the examined horses. Moreover, all examined horses hadmid-sagittal P1 fracture. On CT, 92% of P1 fractures were located in the mid-sagittal plane(Brunisholz et al., 2015). The recorded clinical signs and radiographic findings in this study werepreviously reported (Tetens et al., 1997).

Contrary to our findings, horses treated conservatively by cast and stall rest requiredapproximately 3-4 months of treatment to become free from pain and lameness, in addition theydeveloped exostosis at the fracture site and secondary joint disease that might cause lamenesswhen returned to work (Ellis et al., 1987; Tetens et al., 1997; Kuemmerle et al., 2008). Meanwhile,P1 fractures treated surgically with lag screw fixation, reduced this protracted healing time by halfand resulted in less callus and degenerative joint changes (Holcombe et al., 1995). Lescun et al.(2007) added that the outcome of surgical repair is better than conservative treatment of P1fractures especially comminuted one.

Compared to the previous studies, the present results indicate that addition of DMSO combinedwith corticosteroid to the usual conservative treatment showed dramatic improvement in lamenessand pain in horses suffered from short and long incomplete mid-sagittal fractures and completemid-sagittal fracture of proximal phalanx after 10±1.5, 18±3 and 35±4.7 days of treatment. Thepositive impact of using DMSO with Hydrocortisone in this study support previous suggestions for

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Asian J. Anim. Vet. Adv., 10 (11): 789-796, 2015

Fig. 3(a-b): (a) Dorsopalmar radiographic view of a 5 year-old mare showing old complete fractureof the proximal phalanx (arrow) associated with signs of degenerative joint diseaseand (b) Lateromedial radiographic view of the same mare after 12 weeks of treatmentshowing osteophytes formation at the dorsal aspects of both P1 and metacarpal boneand DJD of fetlock joint (arrows)

treatment of extensive tissue trauma, osteoarthritis and periosteal reaction involving the carpaland fetlock joints and the metacarpal bones with DMSO (Robert, 1982). Moreover, the use ofintra-articular corticosteroids in joint diseases enhances glycosaminoglycan (GAG) content andGAG synthetic rate in the articular cartilage, as well as has potent anti-inflammatory andchondroprotective effects (Mcllwraith, 2002).

Complete mid-sagittal proximal phalanx fractures opening through the lateral cortex wereassociated with synovial effusions in the fetlock joint and digital flexor tendon synovial sheath.Fetlock intra-articular and intra-synovial digital flexor tendon sheaths injections of DMSO andcorticosteroid associated with application of fiberglass cast at the lower limb and box confinementshowed favorable results after 35±4.7 days of treatment and improved well after 85±4.5 days oftreatment. However, surgical lag screw fixation or neutralized plate associated with fiberglass castwas recommended in similar cases before (Ellis et al., 1987; Tetens et al., 1997).

In this study, one mare had an old complete mid-sagittal fracture extending through theproximal inter-phalangeal and fetlock joint that showed no significant improvement, persistencelameness and degenerative joint changes. This could be attributed to the chronicity of the case,

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Asian J. Anim. Vet. Adv., 10 (11): 789-796, 2015

therefore early treatment is recommended for good repair of the complete fracture of P1. Similarfindings have been described during healing of comminuted fracture (Ellis et al., 1987) and duringshort incomplete mid-sagittal fracture (Markel and Richardson, 1985). This poor prognosis forhorses with complete P1 fractures was attributed to the disruption of the articular surface anddevelopment of cartilage erosion and osteophytes (Holcombe et al., 1995). The articular cartilageis a highly differentiated structure and has a limited respiratory potential due to the lake oforganization, lymphatic vessels and innervation (Abu-Seida, 2015).

CONCLUSIONSIn conclusions the addition of fetlock intra-articular and intra-synovial of deep digital flexor

tendon sheaths injection of DMSO combined with corticosteroid to the usual conservative treatmentincluding fiberglass cast and box confinement can exert favorable effects, reduce the healing timeand minimize degenerative joint changes and healing callus in horses suffered from incomplete andcomplete mid-sagittal fractures of the proximal phalanx.

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