Use of a Custom-made Synthetic Internal Brace for the Repair of a Proximal Gastrocnemius Muscle Tear in a Dog

Abstract

Objectives

To describe the surgical procedure and long-term outcome of a complete traumatic tear of the gastrocnemius muscle mass without avulsion in a dog treated by sutures and using a custom-made prothesis as internal brace to support healing.

Case Description

A mix-breed dog had acute right hindlimb lameness caused by a complete proximal tear of both heads of the gastrocnemius muscle with hematoma. The tear was resolved with sutures. The gastrocnemius was augmented using an ultra-high molecular weight polyethylene (UHMWPE) implant sutured to the muscle mass and lengthened with two sutured nylon strands fastened through a bone tunnel drilled in the distal part of the femur to reduce the mechanical constraints on the sutured tear. Clinical, orthopedic, and imaging examinations were performed at 45 days and 8 months postoperatively. A phone call to the owner completed the follow-up at 18 months postoperatively.

Results

The dog bore weight one day after surgery. Normal stance and gait were resumed 45 days after surgery, despite moderate muscle atrophy. At 8 months, the dog had normal gait and moderate muscle atrophy. Muscle mass on the proximal right gastrocnemius muscle was continuous with few signs suggesting muscle fibrosis without any impact on clinical evolution. The owner indicated that the dog had normal gait and recovered muscle mass at 18 months.

Conclusion

This case resulted in a satisfactory functional clinical outcome. This technique could be considered to treat proximal lesions of the gastrocnemius muscle.

Keywords

dog - gastrocnemius - muscle tear - synthetic reconstruction - traumatic - proximal lesion

Introduction

Gastrocnemius muscle injuries can cause lameness, plantigrade stance, and pain. Diagnosis consists of clinical and orthopedic examinations combined with medical imaging such as stress radiographs,[1] [2] diagnostic ultrasonography,[3] computed tomography (CT), and magnetic resonance imaging (MRI).[4] Achilles tendon lesions affecting the myotendinous junction and/or the tendon insertion to the calcaneus[5] [6] are the most common injuries to the gastrocnemius unit.[7] [8] [9] Therapeutic management consists of re-apposition of the tendon ends using various suture patterns[10] [11] [12] or augmentation grafts,[13] [14] metallic plate[15] or synthetic implant,[16] and are supported by either a cast,[11] [16] a splint,[13] or an external fixator.[14] [15]

Proximal lesions with avulsion of the lateral,[1] [6] [17] [18] medial,[5] [19] or both heads[2] of the gastrocnemius muscle are less common. Conservative treatment with nonsteroidal anti-inflammatory drugs (NSAIDs), physiotherapy, and restriction of activity may be considered in partial ruptures.[4] [5] Therapeutic ultrasound[17] and shortwave diathermy[3] have also been proved successful, but surgical reconstruction of the muscle is indicated if lameness and pain persist.[1] [2] [18] Nylon monofilament,[1] cerclage wire,[2] and the combination of a spiked washer with a cortical screw[18] have been used to reattach avulsed gastrocnemius heads on the femur. External coaptation with a type 1a transarticular external fixator placed to maintain the hock in extension[1] or a splint bandage[2] [18] has been used previously to support healing by limiting mechanical strain.

To our knowledge, complete proximal tears of the gastrocnemius muscle belly alone, causing plantigrade stance without detachment of the gastrocnemius sesamoid bones, has not yet been reported; thus, this disruption of the gastrocnemius apparatus represents a therapeutic challenge.

We hereby report the surgical management of a complete proximal rupture of the gastrocnemius muscle. Surgical treatment consisted of restoring muscle function by primary repair of the muscle belly. The use of a synthetic custom-made prosthesis as an internal brace to counteract the tension forces exerted by the gastrocnemius muscle is reported for the first time. The prosthesis was composed of an ultra-high molecular weight polyethylene (UHMWPE) implant, which has already been used for Achilles tendon reconstruction,[16] [20] and which was modified with nylon strands.

Case Description

Clinical History and General Examination

A 6-year-old, 25-kg, neutered-female, mix-breed hunting dog was presented with acute right hindlimb lameness after a wild boar strike. Body temperature as well as biochemical and hematological test results were normal. No wounds were detected.

Orthopedic and Neurological Examination

The dog showed grade IV/IV[21] right hindlimb lameness and plantigrade stance ([Fig. 1A]) with severe pain and swelling of the proximal part of the right gastrocnemius muscle. Complete evaluation of the right talocrural joint showed no signs of inflammation nor instability. Manipulation of the talocrural joint in the physiologic range of motion was painless. The rest of the orthopedic examination, including the stifle joint, was normal. The neurological examination showed no posture, gait, postural reaction, spinal reflex, nor muscle tone/mass abnormalities in both hind limbs.

Fig. 1 Preoperative diagnostic imaging. (A) Plantigrade stance before surgery. (B) Mediolateral (left) and craniocaudal (right) radiographs of right hindlimb show soft tissue inflammation on caudal part of right stifle and absence of bone lesions. (C) Ultrasonography of the proximal part of the right gastrocnemius muscle in a sagittal plane with a linear probe showing a discontinuity in the gastrocnemius muscle hyperechoic fibers (blue arrow) within a hypoechoic fluid cavity (orange arrow). (D) Sagittal CT reconstruction of left (contralateral) hindlimb and (E) sagittal CT reconstruction of right (affected) hindlimb showing presence of hematoma (yellow arrow pointing). (F) Transverse CT reconstruction of right hindlimb showing presence of hematoma (red arrow). (G) Transverse CT reconstruction of left hindlimb.

Diagnostic Imaging Under General Anesthesia

Standard craniocaudal and mediolateral radiographic views of the right stifle (Ralco R 302/A, Italy) showed mild swelling of the soft tissue located caudally to the proximal part of the tibia without evidence of avulsion or fractures of the gastrocnemius sesamoid bones, compared with the contralateral hindlimb ([Fig. 1B]). Computed tomography (Canon Aquilion 80SP, Japan) performed on both hindlimbs showed the presence of a hypoattenuating lesion within the proximal part of the right gastrocnemius muscle with a complete tear at the level of the bifurcation of the muscle heads ([Fig. 1D–G]). Presumptive diagnosis was gastrocnemius muscle tear with hematoma secondary to the trauma. Ultrasonography (Aplio a, micro-convex probe 11MC4 and linear probe L18, Canon Medical System, Japan) showed a discontinuity in the gastrocnemius muscle fibers within a hypoechoic fluid cavity with an absence of parallel muscle fiber striations in the proximal part of the gastrocnemius muscle in the sagittal plane ([Fig. 1C]). Given the active nature of the dog, the use of an external coaptation or fixator without surgical muscle repair was judged inappropriate. Since no obvious macroscopic external signs of contamination (i.e., no wounds) were detected at the site of the injury after shaving and scrubbing of the right hind limb, surgical debridement and repair of the muscle tear with implantation of a synthetic implant as an internal brace was performed 2 days later.

Premedication and Anesthetic Protocol

The dog was premedicated with methadone (Comfortan, Dechra; 0.2 mg/kg intramuscularly [IM]) and dexmedetomidine (Sedator, Dechra; 20 μg/kg IM). General anesthesia was induced with propofol (Proposure, Axience; 2 mg/kg intravenously [IV]) and diazepam (Valium, Roche; 0.1 mg/kg IV), and maintained with an oxygen/isoflurane mixture (Isorane, Axience) after endotracheal intubation. Analgesia was provided by a constant rate infusion of fentanyl (Fentadon, Dechra; 10 μg/kg/h). Antibiotics (amoxicillin/clavulanic acid, Levmentin, Delbert; 22 mg/kg IV) were administered 1 hour before surgery and repeated every 90 minutes.

Surgical Treatment

The dog was positioned in left lateral recumbency. After aseptic preparation of the site, a caudolateral approach to the right hindlimb was performed from the middle of the Achilles tendon to the distal part of the femur. A large hematoma was detected within the tear of both heads of the gastrocnemius muscle ([Fig. 2A]). The talocrural joint was then extended to suture the muscle tear. A total of 30 interrupted pattern sutures were placed between both parts of the muscle tear inside the muscle mass to re-appose the ends and the surrounding fascia ([Fig. 2B]).

Fig. 2 Reconstruction technique and peroperative procedures. (A) Identification of gastrocnemius muscle tear which was sutured (B). Prosthesis (C) was sutured to the distal part of gastrocnemius muscle (D), passed under biceps femoris (E), and attached to distal femur (F). (G–H) Three-dimensional images of the gastrocnemius muscle tear after surgery.

A custom-made prosthesis composed of a synthetic UHMWPE implant (Novaten 8000, Novetech Surgery, France), augmented with two nylon strands (Ethilon nylon tape 6 mm × 70 cm, polyamide 66, Ethicon) sutured by two uninterrupted non-absorbable sutures, was used to provide enough length to reach the distal femur from the proximal tibia ([Fig. 2C–H]). The UHMWPE part of the prosthesis was sutured to the distal gastrocnemius muscle from the distal musculotendinous junction to the tear by 30 interrupted pattern sutures ([Fig. 2D, H]). The prosthesis was passed underneath the biceps femoris muscle ([Fig. 2E]). A tunnel was then drilled lateromedially through the distal femur using a 1.8-mm drill bit, proximal to the level of the gastrocnemius sesamoid bones ([Fig. 2G]). The lateral strand of the prosthesis was inserted laterally to medially, while the medial strand was passed medially to laterally. Both strands were fastened with a surgeon's knot and four simple knots over the caudal distal femur. Appropriate tension was applied and adjusted subjectively to maintain good strength on the prosthesis and decrease the tension on the muscle tear, while avoiding over-tensioning which might have hyperextended the talocrural joint. The surgical site was profusely flushed with sterile saline. A bacteriology swab was taken from the surgical site before routine closure (microbial cultures were negative). Surgery time was 100 minutes. Immediate postoperative radiographs showed satisfactory femoral bone tunnel placement ([Fig. 3]). Flexion and extension of both tarsal and stifle joints were within physiological range. The implant remained stable when significant forces were applied on both the stifle and talocrural joints. A modified Robert-Jones bandage with a splint was applied on the right thigh.

Fig. 3 Immediate postoperative craniocaudal (left) and mediolateral (right) radiographs of right hindlimb showing reconstruction of gastrocnemius muscle.

Postoperative Management

Analgesia (morphine, Aguettant; 0.3 mg/kg) was administered every 4 hours, as well as NSAIDs (Meloxidyl, Ceva; 0.1 mg/kg) once a day and antibiotics (amoxicillin/clavulanic acid, Levementin, Delbert; 22 mg/kg IV) twice a day. The dog was leash-walked every 3 to 4 hours and discharged 1 day postoperatively. The owner was instructed to restrict its activity with strict rest for 45 days, and two to three 10-minute leash walks per day. Removal of the Robert-Jones bandage, wound cleaning, and renewal of the bandage were performed every 4 days until 45 days post-surgery. The Robert-Jones bandage was excessively loose at the first visit for bandage renewal.

Long-term Postoperative Examination

At 45 days postoperatively, clinical and orthopedic examinations showed normal stance and gait ([Fig. 4A]). Moderate right hindlimb muscle atrophy was present. Manipulation of the operated limb was painless with a satisfactory range of motion and resistance of the talocrural joint. Radiographs did not show any signs of complications ([Fig. 4B]). Physiotherapy was recommended but was declined by the owner.

Fig. 4 Follow-up examination at 45 days postoperatively. (A) Normal standing posture on operated hindlimb. (B) Craniocaudal (left) and mediolateral (right) radiographs of right hindlimb showing satisfactory reconstruction of gastrocnemius muscle.

At 8 months postoperatively, the dog had a normal gait. Radiographs showed no abnormalities ([Fig. 5A]). Computed tomography of the right hind limb showed a moderate gastrocnemius muscle atrophy of approximately 25% relative to the contralateral limb ([Fig. 5B]). Ultrasonography showed a continuous muscle mass on the proximal right gastrocnemius muscle, with a few signs of muscle fibrosis ([Fig. 5C]). The presence of the prosthesis prevented the assessment of fibrosis in the gastrocnemius muscle via ultrasonography. However, T1-weighted MRI of the right gastrocnemius muscle (1.5T MRI, Siemens Magnetom, Germany) evidenced an increase in signal intensity in the region of the gastrocnemius muscle lesion, which is a potential indicator of muscle fibrosis, indicating that the muscle has healed by secondary intention ([Fig. 5D, E]). The presence of muscle fibrosis had no apparent influence on the clinical outcome. The owner indicated that the dog resumed hunting 6 months postoperatively without any lameness.

Fig. 5 Follow-up examination at 8 months postoperatively. (A) Mediolateral and craniocaudal radiographs of right hindlimb showing satisfactory reconstruction of gastrocnemius muscle. (B) CT showing frontal reconstruction of both hindlimbs with mild right limb muscle atrophy. (C) Longitudinal ultrasonography of gastrocnemius muscle showing an irregularly thickened, hyperechoic muscle fibers (white asterisk) with no clear fiber pattern. (D) MRI showing sagittal reconstruction of proximal part of right (affected) gastrocnemius muscle with fibrous shaping of muscle (yellow asterisk). (E) MRI showing sagittal reconstruction of proximal part of left (contralateral) gastrocnemius muscle with normal gastrocnemius muscle (red asterisk).

During a phone call at 18 months postoperatively, the owner indicated that the dog had a normal gait at both walk and trot and had regained its muscle mass.

Discussion

The use of a synthetic internal brace was a viable augmentation to support healing in the treatment of this complete proximal tear of the gastrocnemius muscle belly without obvious cutaneous penetration. The dog showed excellent recovery, resuming normal gait at 2 months and up to 18 months postoperatively without any complications.

In the absence of preoperative MRI, ultrasonography was helpful to diagnose the complete gastrocnemius tear and the extent of the lesion.[3] Computed tomography completed the diagnostic by highlighting the presence of hematoma within the tear, confirmed peroperatively. Craniocaudal and mediolateral radiographs of the limb allowed to eliminate potential concomitant injuries (i.e., calcaneum fracture, gastrocnemius sesamoid bone luxation, etc.) that could lead to a plantigrade stance after a trauma. Postoperatively, MRI allowed to assess the development of fibrosis, which was not possible with ultrasonography due to the presence of the prosthesis.

It is reported that conservative treatment such as rest, physiotherapy and NSAIDs,[4] [5] therapeutic ultrasound,[17] and shortwave diathermy[3] may yield satisfying outcomes for proximal tears. Considering the complete tear of the gastrocnemius muscle, its role in tarsal joint extension and stifle flexion,[22] and given the active nature of this hunting dog, conservative treatment was not considered. External coaptation or an external fixator without surgical muscle repair were also not suitable and failure would have resulted in negative outcome. Surgical reconstruction of the muscle tear and the use of a device to reduce the mechanical strain applied to the surgical site were deemed preferable.

Three options were available: a splint bandage,[2] [18] an external fixator applied to the stifle joint,[1] or an internal brace augmentation. Internal brace augmentation with a Robert-Jones bandage seemed to be the most suitable option, since the bandage alone did not fully immobilize the stifle joint.

The use of an UHMWPE implant as an internal brace presented several advantages. It is a biocompatible material which is well tolerated by the organism,[23] the implant alone can withstand mechanical forces up to 8000 N, and its fixation can withstand 685 N, as observed when tested ex vivo in an Achilles tendon repair model.[20]

Several parameters inherent to implant design needed to be considered before surgery. First, as the implant is braided, it could have increased the risk of infection, especially in the event of superficial subcutaneous infection.[24] The laceration-like aspect of the tear is usually associated with penetrating injuries which may also affect the sciatic nerve and/or the artery. Since no wound was observed on the dog, even after shaving and scrubbing the limb, the muscle injury was considered not to be infected. The bacteriological sample taken after the surgery showed no signs of bacterial growth, and no postoperative infection was observed. If a small penetrating injury was missed, this could have caused postoperative infections requesting implant removal.

Second, the UHMWPE implant alone was too short to be sutured to the distal gastrocnemius muscle and attached to the distal femur. The implant could have been sutured to the muscle from the distal myotendinous junction up to the proximal tibia. However, this would likely not have reduced the mechanical strain sufficiently. Two nylon strands were thus affixed on the proximal part of the UHMWPE implant to gain length for secure attachment through a bone tunnel in the distal femur. The UHMWPE part was sutured from the distal myotendinous junction up to the tear, and then placed freely against the gastrocnemius muscle from the tear up to the stifle where nylon strands anchored the prosthesis to the distal femur.

Third, tearing out of the tendinous sutures was the only failure mode recorded for this UHMWPE implant during biomechanical tests on Achilles tendon repair.[20] Interrupted pattern sutures were used, as in the biomechanically tested technique[20] and in clinical cases[16] of canine Achilles tendon repair. The nylon strands were fastened over the distal femur after having been passed through a bone tunnel. The latter was drilled in the distal femur so that the prosthesis could be placed parallel to the gastrocnemius muscle fibers to fully counteract tension forces. Fastening the strands together was preferred instead of placing an interference screw in the tunnel, as the screw might have damaged the nylon strands owing to their relatively small thickness, which could then have resulted in fixation failure.

Implant failure in the early postoperative period would have been dramatic, as the muscle and fascia sutures would not have resisted the tension. Implant failure after 2 or 3 months postoperatively would have been less problematic, since muscle healing would have progressed sufficiently. The prosthesis acted as an internal brace suppressing the forces exerted on the sutured muscle tear, similar to the effect of an external fixator. The efficacy of the prosthetic implant was supported by the fact that the Robert-Jones bandage did not immobilize the stifle joint the same way a transarticular external fixator would have done, and also by the absence of clinical consequences of an excessively loose Robert-Jones bandage during the first days postoperatively due to poor compliance with postoperative recommendation. The prosthesis may have helped the dog to resume early weight-bearing[16] by supporting the mechanical forces during locomotion, thus attenuating postoperative lameness. By allowing some motions of the limb muscles, the use of a synthetic internal brace may have limited atrophy or quadriceps contracture, which would have been expected to be more important with a transarticular fixator.

The prosthesis also had the advantage of avoiding infections associated with an external fixator.[9] In the event of inflammatory reaction or infection, the prosthesis could have been removed after the muscle fibers had healed. As no obvious negative effects was observed, there was no reason to remove the prosthesis.

In light of this satisfactory functional clinical outcome, this technique could be considered to treat similar gastrocnemius muscle injuries.

Conflict of Interest

C.A. and G.B. are employed by Novetech Surgery. The authors declare no additional conflict of interest.

Acknowledgments

The authors thank Mrs Cooke-Martageix E. for copyediting.

Author Contributions

R.G. and B.J.-F. examined the dog, diagnosed the pathology, performed surgery, performed follow-up visits, analyzed data, wrote and revised the manuscript. C.A. and G.B. analyzed data, wrote and revised the manuscript.

• References

• 1 Ridge PA, Owen MR. Unusual presentation of avulsion of the lateral head of the gastrocnemius muscle in a dog. J Small Anim Pract 2005; 46 (04) 196-198
• 2 Robinson A. Atraumatic bilateral avulsion of the origins of the gastrocnemius muscle. J Small Anim Pract 1999; 40 (10) 498-500
• 3 Lideo L, Milan R. Ultrasound monitoring of shortwave diathermic treatment of gastrocnemius strain in a dog. J Ultrasound 2013; 16 (04) 231-234
• 4 Stahl C, Wacker C, Weber U. et al. MRI features of gastrocnemius musculotendinopathy in herding dogs. Vet Radiol Ultrasound 2010; 51 (04) 380-385
• 5 Muir P, Dueland RT. Avulsion of the origin of the medial head of the gastrocnemius muscle in a dog. Vet Rec 1994; 135 (15) 359-360
• 6 Ting D, Petersen SW, Mazzaferro EM, Worth LT, Petersen SW. American College of Veterinary Radiology. What is your diagnosis? Avulsion of the origin of the gastrocnemius muscle. J Am Vet Med Assoc 2006; 228 (10) 1497-1498
• 7 Kramer M, Gerwing M, Michele U, Schimke E, Kindler S. Ultrasonographic examination of injuries to the Achilles tendon in dogs and cats. J Small Anim Pract 2001; 42 (11) 531-535
• 8 Meutstege FJ. The classification of canine Achilles' tendon lesions. Vet Comp Orthop Traumatol 1993; 06 (01) 53-55
• 9 Nielsen C, Pluhar GE. Outcome following surgical repair of Achilles tendon rupture and comparison between postoperative tibiotarsal immobilization methods in dogs: 28 cases (1997-2004). Vet Comp Orthop Traumatol 2006; 19 (04) 246-249
• 10 Duffy DJ, Chang Y-J, Gaffney LS, Fisher MB, Moore GE. Effect of bite depth of an epitendinous suture on the biomechanical strength of repaired canine flexor tendons. Am J Vet Res 2019; 80 (11) 1043-1049
• 11 Frame K, Ben-Amotz O, Simpler R, Zuckerman J, Ben-Amotz R. The use of bidirectional barbed suture in the treatment of a complete common calcanean tendon rupture in a dog: long-term clinical and ultrasonographic evaluation. Clin Case Rep 2019; 7 (08) 1565-1572
• 12 Moores AP, Owen MR, Tarlton JF. The three-loop pulley suture versus two locking-loop sutures for the repair of canine Achilles tendons. Vet Surg 2004; 33 (02) 131-137
• 13 Katayama M. Augmented repair of an Achilles tendon rupture using the flexor digitorum lateralis tendon in a Toy Poodle. Vet Surg 2016; 45 (08) 1083-1086
• 14 Tidwell SJ, Greenwood K, Franklin SP. Novel Achilles tendon repair technique utilizing an allograft and hybrid external fixator in dogs. Open Vet J 2022; 12 (03) 335-340
• 15 Zellner EM, Hale MJ, Kraus KH. Application of tendon plating to manage failed calcaneal tendon repairs in a dog. Vet Surg 2018; 47 (03) 439-444
• 16 Buttin P, Goin B, Cachon T, Viguier E. Repair of tendon disruption using a novel synthetic fiber implant in dogs and cats: the surgical procedure and three case reports. Vet Med Int 2020; 2020: 4146790
• 17 Mueller MC, Gradner G, Hittmair KM, Dupré G, Bockstahler BA. Conservative treatment of partial gastrocnemius muscle avulsions in dogs using therapeutic ultrasound—a force plate study. Vet Comp Orthop Traumatol 2009; 22 (03) 243-248
• 18 Prior JE. Avulsion of the lateral head of the gastrocnemius muscle in a working dog. Vet Rec 1994; 134 (15) 382-383
• 19 Chaffee VW, Knecht CD. Avulsion of the medical head of the gastrocnemius in the dog. Vet Med Small Anim Clin 1975; 70 (08) 929-931
• 20 Buttin P, Goin B, Crumière AJJ. et al. Ex-vivo biomechanical analysis of an original repair of canine calcaneal tendon rupture using a synthetic implant as mechanical support fixed by sutures in the proximal tendinous part and by an interference screw in the bone distal part. Open Vet J 2023; 13 (05) 645-653
• 21 Millis DL, Mankin J. Orthopedic and neurologic evaluation. In: Millis DL, Levine D. , editors. Canine Rehabilitation and Physical Therapy. 2nd ed. Philadelphia, PA, USA: Elsevier; 2014: 180-200
• 22 Hermanson JW. The muscular system. In: Evans HE, de Lahunta A. eds. Miller's Anatomy of the Dod. 4th ed. St. Louis, Missouri, US: Elsevier Saunders; 2013: 185-280
• 23 Smith PA, Bozynski CC, Kuroki K, Henrich SM, Wijdicks CA, Cook JL. Intra-articular biocompatibility of multistranded, long-chain polyethylene suture tape in a canine ACL model. J Knee Surg 2019; 32 (06) 525-531
• 24 Dhom J, Bloes DA, Peschel A, Hofmann UK. Bacterial adhesion to suture material in a contaminated wound model: comparison of monofilament, braided, and barbed sutures. J Orthop Res 2017; 35 (04) 925-933

Publication History

Received: 25 July 2024

Accepted: 27 January 2025

Article published online:
08 April 2025