Abstract
Objective
To evaluate the clinical feasibility and efficacy of a video-assisted ligamentoplasty of the medial glenohumeral ligament for the treatment of medial shoulder joint instability in dogs.
Animals
This retrospective study included 6 dogs with medial shoulder instability treated by video-assisted ligamentoplasty of the medial glenohumeral ligament. Inclusion criteria required documented medical records containing signalment, clinical history, diagnostic imaging, surgical details, and postoperative assessments, along with a minimum follow-up period of 6 months. Complications and midterm outcomes were recorded.
Clinical Presentation
The 6 dogs exhibited a weight-bearing lameness, and during the orthopedic examination under sedation, an abduction angle exceeding 35° was observed.
Results
All joints were stabilized successfully. The abduction angle immediately after repair was 17.5 ± 1.2° and after 6 months 24.6 ± 1.8°. Postoperative shoulder stability was satisfactory, with excellent functional recovery in 5 dogs and good recovery in 1 dog. No complications occurred.
Clinical Relevance
Video-assisted shoulder stabilization is feasible in dogs and appears to yield satisfactory clinical results. This novel technique shows promising results and encourages the development of minimally invasive techniques for an optimal patient recovery.
The stability of the shoulder joint is mainly provided by the soft tissues surrounding the joint. Indeed, the anatomic conformation of the glenohumeral joint does not allow a stable socket, thus explaining why the joint relies heavily on capsuloligamentous supports to provide stability. These are divided into active (biceps brachii, subscapularis, supraspinatus, infraspinatus, and teres minor muscles and the biceps brachii tendon) and passive (joint capsule and medial and lateral glenohumeral ligaments) stabilizers.1 The glenohumeral ligaments are paired ligaments located on both the medial and lateral aspects of the glenohumeral joint, playing a crucial role as the main stabilizers of the shoulder joint. The medial glenohumeral ligament (MGHL), a Y-shaped structure with a cranial and caudal arm, is the most significant stabilizer. It originates proximally on the anterosuperior part of the glenoid labrum and inserts distally on the lesser tuberosity. Injury to any part of the capsuloligamentous support structures, including the MGHL, can lead to shoulder joint instability, resulting in pain and dysfunction.2
Shoulder instability is one of the most common shoulder pathologies in dogs, with medial shoulder instability (MSI) being the most frequent (78%).3 Medial shoulder instability or subluxation of the shoulder joint occurs when the MGHL, the subscapularis tendon (SST), or the shoulder joint capsule get inflamed and become progressively more lax and more frayed.4 The condition affects both large- and small-breed dogs. Two main types of instability are described: acquired and congenital. In large-breed dogs, MSI is generally thought to be secondary to trauma, whereas congenital laxity is considered more common in small and toy breeds.5
Suspicion of MSI requires manipulation of the joint and measurement of the abduction angle.6 To confirm the diagnosis, medical imaging examinations can be used, like stress radiography, musculoskeletal ultrasound,7–9 CT, or MRI.
Surgical treatment is 3 times more likely to be associated with a successful outcome than nonsurgical management.3,10 Surgery is more effective on animals that have suffered trauma rather than on congenital cases.11
Several surgical techniques are available to stabilize the shoulder, among which are radiofrequency-induced thermal capsulorrhaphy,12 ligamentoplasty of the MGHL with different techniques using anchors,13 toggle sutures,14 screws with spiked washers,15 interference screws with synthetic implants,16 and imbrication of the tendon of the SM.17
These techniques are mainly performed as open procedures with a delicate approach requiring several muscle detachments that can compromise the quality of recovery.18 Moreover, there is no superior treatment method for MSI in dogs nowadays.19 Arthrodesis of the shoulder may be considered when osteoarthritis is severe20,21 or when shallowness is present when we have congenital abnormalities.
While minimally invasive surgery is well established and is known to reduce postoperative pain with faster recovery in human medicine, arthroscopic treatment is increasingly developing in veterinary medicine.22–24
Different video-assisted techniques have been described in dogs for surgical management of MSI, such as arthroscopic imbrication of the MGHL and the SST with knotless anchors,25 the use of an intra-articular aiming device with a suture-toggle repair, or an interference screw repair using bone anchors arthroscopically assisted.26
Recently, Llido et al27 described in dog cadavers an arthroscopically guided ligamentoplasty technique using a bone anchor placed at the medial aspect of the distal scapula and a bone tunnel drilled across the proximal humeral metaphysis through which the suture was passed prior to being tied on the lateral side using a button. The aim of this study was to evaluate the clinical feasibility and efficacy of this last technique for the treatment of medial shoulder joint instability in dogs.
Methods
Case selection criteria
The medical records of all dogs diagnosed with MSI based on clinical examination, diagnostic imaging, and arthroscopic exploration of the shoulder and surgically treated by video-assisted ligamentoplasty were retrospectively reviewed.
Dogs treated from 2019 through 2023 at VetAgro Sup Lyon veterinary campus were included in the study if their medical record contained signalment, clinical history, diagnostic imaging, surgical details, and postoperative assessments; if they were treated with a video-assisted ligamentoplasty of the glenohumeral ligament with a bone anchor as described by Llido et al27; and if a minimum of 6 months follow-up was available to ensure adequate time for the development of complications.
Medical records review
This retrospective study included dogs that demonstrated lameness and shoulder instability at the clinical examination. Data obtained from the electronic medical records included signalment (age, sex, breed, and bodyweight), affected limb, duration of clinical signs prior to surgical intervention, lameness score before and after the surgery, shoulder abduction angles before and after surgery, diagnostic imaging findings, arthroscopic findings, type of implants used, postoperative complications, and duration of follow-up. Shoulder abduction angles before and after surgery were measured by only 1 observer to reduce bias. For the shoulder abduction test in dogs, the examiner begins by stabilizing the scapula with one hand to prevent any compensatory movement that could distort the measurement. With the other hand, they grasp the tested thoracic limb by holding the elbow and carpus while keeping the shoulder in 90° flexion. Then, a progressive force is applied to abduct the limb, meaning to move it away from the body’s midline. This movement is performed slowly until resistance is encountered. Once the maximum abduction is reached, the angle is measured using a goniometer, aligning 1 arm of the device with the humerus and the other with the limb’s axis. This measurement helps assess the laxity of the scapulohumeral joint.
Medial shoulder instability encompassed partial or complete tears of the MGHL, the SST, or the medial joint capsule. Lameness was assessed using a scale ranging from 0 to 5: 0, clinically sound; 1, barely detectable; 2, mild; 3, moderate; 4, severe; and 5, non–weight-bearing lameness.
Preoperative diagnostic imaging
For each dog suspected of MSI, 2 standard orthogonal radiographic projections (mediolateral and caudocranial) of the shoulder were taken preoperatively. Stress radiographs were taken to assess the joint space. For stress radiography, the scapula was stabilized against the thorax using a radiographic positioning device, and the shoulder was passively abducted.28 All images were examined by the surgeon and the board-certified radiologist for signs of pathological changes, like osteophytosis, soft tissue calcification, and joint incongruency.
Findings from preoperative ultrasonographic examinations of the shoulder joint region, when performed, were recorded and reviewed by a board-certified radiologist.
The visualization of intra-articular ligamentous structures, particularly on the medial side of the joint, such as the MGHL, is limited by the presence of the pectoral muscles. Therefore, the ultrasound examination must be performed by an experienced operator and with high-quality equipment. If the lesion is not directly visible, a rupture of the ligament may be suspected by the identification of joint space widening.
Surgical procedure
Dogs were premedicated with methadone (0.2 mg/kg, IV), induced with propofol and diazepam to effect, and maintained with an isoflurane-oxygen mixture delivered by a rebreathing system.
Analgesia was provided by methadone and either a cervical paravertebral or a subscalene block with ropivacaine 1%.
Potentiated amoxicillin—clavulanic acid (20 mg/kg, IV) was administered 30 minutes before skin incision and every 90 minutes thereafter throughout the surgery.
All procedures were performed by a single board-certified surgeon with the technique previously described by Llido et al.27
Arthroscopy
Each dog was largely clipped and prepared to allow access to both the medial and lateral aspect of the shoulder. The subject was placed in dorsal recumbency for aseptic draping and was first tilted laterally with the affected limb uppermost to perform the arthroscopy. A standard lateral procedure was performed with a caudolateral camera portal and a craniolateral instrument portal, and a complete exploration of the shoulder joint was carried out with a 2.4-mm, 30° oblique rigid arthroscope (Arthrex) with a SynergyUHD4 4K camera system (Arthrex; Figure 1). The Outerbridge classification was used for cartilage damage. This classification has 4 grades: grade 1, where the cartilage softens and swells; grade 2, showing superficial fissures affecting less than 50% of the depth; grade 3, with deeper fissures extending beyond 50%; and grade 4, where the cartilage is completely worn away, exposing the subchondral bone.29
Immediate postoperative radiographs were performed to evaluate the position of the bone anchor, bone tunnel, and button.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0388
Arthroscopically guided ligamentoplasty
Following arthroscopic shoulder joint exploration, the patient was replaced in dorsal recumbency with the limb of interest suspended while keeping the arthroscope in the joint (Figure 2).
A—A complete exploration of the shoulder joint was carried out with a 2.4-mm, 30° oblique rigid arthroscope (Arthrex) with a SynergyUHD4 4K camera system (Arthrex) with a lateral approach with a suspended limb. In the arthroscopy image, the glenoid is on the top, and at the bottom there is the humeral head. A lesion of the medial glenohumeral ligament is visible. B—Patient was replaced in dorsal recumbency with the limb of interest hung while keeping the arthroscope in the joint. An 18-gauge needle was introduced cranially to the subscapular muscle. A 2- to 3-cm incision was made through the skin, soft tissues, and the joint capsule with a No. 11 scalpel blade alongside the needle. C through E—A pin and a drilling guide were inserted and positioned in the glenoid cavity between the insertion of the cranial and caudal arm of the medial glenohumeral ligament. We had to drill until the black mark. F—A bone anchor adapted to the size of the dog and preloaded with a braided suture combining high-molecular-weight polyethylene and polyester (Fibertape; Arthrex) was placed. G—A bone tunnel was then drilled into the humeral head. H—The suture was finally shuttled from medial to lateral through the bone tunnel and tied over a button (2-hole Titanium Suture Buttons; Arthrex) on the lateral side while maintaining shoulder adduction.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0388
For the video-assisted ligamentoplasty of the MGHL, the arthroscope was placed in a caudolateral position to visualize the cranio-medial part of the glenoid. An 18-gauge needle was introduced cranially to the subscapular muscle to minimize iatrogenic muscle damage and was directed from cranio-medial to caudo-lateral. A 2- to 3-cm incision was made through the skin, soft tissues, and the joint capsule with a #11 scalpel blade alongside the needle. A drilling guide was inserted and positioned on the medial aspect of the glenoid between the origin of the cranial and caudal arm of the MGHL. After drilling, a bone anchor appropriate to the size of the dog and preloaded with a braided suture combining high-molecular-weight polyethylene and polyester (Fibertape; Arthrex) was placed (Figure 2).
A bone tunnel was drilled into the humeral head. Drilling was performed with a 2.0-mm Steinmann pin from medial to lateral. The Steinmann pin was introduced through the skin incision previously performed to place the bone anchor on the medial side. The insertion drilling point was centered on the humeral head distally to the insertion of the joint capsule and was oriented toward the greater tubercle. A minimal lateral approach of the proximal humerus was made to visualize the exit point of the tunnel. The tunnel was then enlarged with a 3.0-mm cannulated drill bit from medial to lateral. The Steinmann pin was removed, and a wire passer was introduced within the cannulated drill bit to grab the suture strands still attached to the anchor on the medial side and pass them to the lateral side. The drill bit was then removed from the lateral side. The suture was finally shuttled from medial to lateral through the bone tunnel and tied over a button (2-hole Titanium Suture Buttons; Arthrex) on the lateral side while maintaining shoulder adduction. After abundant lavage, closure of the joint capsule, SC tissues, and the skin was performed. For the closure of the joint capsule, a resorbable polydioxanone monofilament suture was used, followed by a resorbable polyglecaprone monofilament suture for the SC layer, and finally a nonresorbable nylon monofilament suture for the skin.
Immediate postoperative radiographs were performed to evaluate the position of the bone anchor, bone tunnel, and button (Figure 1). The immediate postoperative abduction angle was recorded after the postoperative radiographs.
Postoperative care
Analgesia consisting of methadone (0.2 mg/kg, IV), paracetamol (10 mg/kg, PO), and meloxicam (0.1 mg/kg, PO) was administered during hospitalization. A hobble-limiting abduction (Balto; Mikan) was placed immediately after surgery and was to be kept in place for 6 to 8 weeks.
Patients were discharged the following day after surgery with a prescription for an NSAID (meloxicam, 0.1 mg/kg, PO, q 24 h, for 3 weeks). Owners were asked to confine their dogs to a small room, and short leash walks 4 times daily were the only recommended activity during the initial 6 to 8 weeks after surgery until clinical and radiographic recheck. Activities were gradually introduced 12 weeks after surgery. Rehabilitation therapy with a certified veterinary practitioner was advised after the initial period of rest. After the first recheck, uncontrolled activities were gradually introduced, and underwater treadmill training was implemented.
Outcomes
Six to 8 weeks after surgery, all dogs came for an assessment at VetAgro Sup Lyon veterinary campus; a clinical examination and radiographs were performed by the board-certified surgeon who had conducted the surgery. Information for the follow-up was recorded in a spreadsheet: lameness score; shoulder abduction angle; orthopedics findings, like muscle atrophy; pain on shoulder manipulation; range of motion; joint effusion; and rehabilitation therapy.
Return to activity was advised if possible. Dogs were reevaluated by the surgeon after 6 months. Owners graded the outcome of the dog. Owners were asked about their satisfaction with the operation, with scores ranging from 1 (not satisfied) to 5 (very satisfied). Radiographs and measurements of abduction angles under sedation were suggested to the owners.
Statistical analysis
Data were entered into Excel (Microsoft Corp) for descriptive statistical analysis, including the calculation of medians and ranges. Statistical analyses were performed using R (version 4.5.0; The R Foundation for Statistical Computing). To assess the assumption of normality required for parametric testing, the Shapiro-Wilk test was applied to the shoulder abduction angle data at each time point. A normal distribution was confirmed at all 3 time points (P > .05 for all time points).
A repeated-measures ANOVA was conducted to assess differences in shoulder abduction angles over time. When a significant main effect of time was identified, post hoc pairwise comparisons were performed using Bonferroni-adjusted P values to control for multiple comparisons. All time points were compared pairwise (before vs immediately after the operation, before the operation vs 6-week follow-up, and immediately after the operation vs 6-week follow-up).
Results
From February 2019 through January 2023, 6 dogs were operated on using this technique and had a follow-up of around 180 days.
Six dogs met the inclusion criteria. Among these 6 dogs, 1 was a hunting dog, and the other 5 did not have any specific activity. All had a history of trauma. The median age was 6 years (range, 5 to 8 years), and the median bodyweight was 19.5 kg (range, 7.5 to 28 kg). Forelimb lameness was present for a median of 59 days prior to the first medical consultation (range, 15 to 120 days).
At the first presentation, all dogs presented thoracic limb lameness, and the preoperative median lameness score was 2.5 (range, 1 to 3). They all showed pain during shoulder examination, and 2 dogs presented supraspinatus, infraspinatus, deltoid, and subscapularis muscular atrophy.
After sedation, the median abduction angle was 54.5° (range, 47° to 60°) on the affected thoracic limb.
Preoperative radiographic examinations were unremarkable for all dogs except 1. Radiographic findings in this dog included moderate osteoarthritis and shoulder subluxation. An ultrasonographic examination of the shoulder joint was performed in 5 dogs. An increased amount of synovial fluid was visualized in the medial and lateral regions in 5 dogs, and opening of the joint space on the medial side with an increased distance between the glenoid cavity and the humeral head was noted in 2 dogs. Ultrasound images consistent with bicipital tenosynovitis were also recorded in 1 dog (Table 1).
Preoperative and operative patient details.
| Case 1 | Case 2 | Case 3 | Case 4 | Case 5 | Case 6 | |
|---|---|---|---|---|---|---|
| Sex | F | F | MN | M | MN | FN |
| Age (y) | 6 | 5 | 7 | 5 | 8 | 5 |
| Breed | Border Collie | English Setter | Yorkshire X Dachshund | Staffordshire Bull Terrier | Australian Shepherd | Mixed breed |
| Weight (kg) | 16 | 20 | 7.5 | 21 | 24.5 | 28 |
| Activity | Companion | Field trial | Companion | Companion | Companion | Companion |
| History | Jumping into a ditch | Trauma during field trial training | No trauma observed | Fall on shoulder | Lameness after a race | Lameness after a jump |
| Duration of lameness (d) | 100 | 60 | 120 | 15 | 30 | 30 |
| Lameness score | 4/5 | 3/5 | 2/5 | 1/5 | 3/5 | 3/5 |
| Orthopedic findings | Pain on shoulder extension | Pain on shoulder extension/flexion | Pain on external rotation of shoulder | Pain on shoulder extension | Pain on shoulder extension/flexion | Pain on shoulder extension |
| Abduction angle | 60° | 55° | 50° | 60° | 47° | 55° |
| Radiographic findings | Moderate osteoarthritis | WNL | WNL | WNL and shoulder subluxation | WNL | WNL |
| Echographic findings | Bicipital tenosynovitis, synovial effusion, enthesophytes | Increase in the joint space. Synovial effusion | NR | Increase in the joint space. Synovial effusion | Synovial effusion | Synovial effusion |
| Arthroscopic findings | Tear of the cranial branch of the MGHL and of the craniodistal part of the SST | Tear of SST in the craniodistal region and distension of the MGHL | Severe distension of the MGHL and SST | Laxity and partial tearing of the MGHL and SST | Tear of the cranial branch of the MGHL and of the craniodistal part of SST | Tear of the cranial branch of the MGHL |
| Anchors (SwiveLock; mm) | 3.5 | 3.5 | PushLock 2.9 | 3.5 | 3.5 | 4.75 |
| Immediate abduction angle | 18° | 18° | 16° | 19° | 16° | 18° |
Lameness was scored on a numerical rating scale from 0 to 5 as previously described: 0, clinically sound; 1, barely detectable; 2, mild; 3, moderate; 4, severe; and 5, non–weight-bearing lameness.
BBT = Biceps brachii tendon. F = Female. FN = Female neutered. M = Male. MGHL = Medial glenohumeral ligament. MN = Male neutered. NR = Not realized. SST = Subscapularis tendon. WNL = Within normal limits.
In all dogs, arthroscopic evaluations revealed synovitis with numerous inflamed joint villi and a lesion of the MGHL.
A complete tear of the cranial branch of the MGHL was visualized in 4 dogs, and the MGHL was severely distended with ruptures of some fibers in the other 2 dogs. Those lesions were associated with a partial tear of the SST in 4 dogs and with only laxity with fibrillations of the tendon in the remaining 2 dogs.
All dogs exhibited cartilage abnormalities. Using the Outerbridge grading system, 4 of them were classified as grade 2, whereas 2 were classified as grade 3.
Video-assisted ligamentoplasty was performed with screwed knotless anchors (SwiveLock; Arthrex) preloaded with 2-mm polyethylene tape (Fibertape) in 5 dogs and with impacted knotless anchors (PushLock; Arthrex) preloaded with the same suture in 1 dog. Details of the bone anchors sizes are shown in Table 1. No intraoperative complications were reported. The mean duration of the surgery was 1.5 hours.
The immediate postoperative abduction angles had a median of 17.5° (range, 16° to 19°; Table 1). This radiograph confirmed the correct placement of the bone anchor, the humeral bone tunnel, and the button, with no signs of malpositioning or complications. The joint alignment appeared satisfactory, and no evidence of implant migration or fixation failure was observed. As a result, revision surgery was deemed unnecessary.
At the 8-week postoperative checkup, 4 dogs had a grade 1 thoracic limb lameness. One had discomfort on flexion of the shoulder, 1 presented moderate amyotrophy, and the other 2 presented a slight amyotrophy. Two dogs had a grade 2 thoracic limb lameness with discomfort on flexion of the shoulder (n = 2) and extension (n = 1).
Radiographic examinations were unremarkable in all dogs, with no widening of the bone tunnel, and shoulder stability was considered satisfactory, with an abduction angle less than 30° in all cases and a median of 24.6° (range, 22° to 27°). An increase in the angle of abduction was noted between the postoperative period and 6-week recheck (7.2°).
The graph (Figure 3) shows a significant improvement in the shoulder abduction angle after surgery and 6 weeks later. Descriptive statistics showed a mean shoulder abduction angle of 54.5° (± 1.33°) before surgery, which decreased to 17.5° (± 1.33°) immediately after surgery and increased to 24.7° (± 1.33°) 6 weeks after the operation.
Evolution of shoulder abduction angle before and after surgery. The graph shows a significant improvement in the shoulder abduction angle after surgery and 6 weeks later. The x-axis (time) represents the 3 evaluation periods: before the operation, immediately after the operation, and 6 weeks after the operation. The y-axis (shoulder abduction angle [°]) indicates the shoulder abduction angle in degrees.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0388
The analysis revealed a significant effect of time on shoulder abduction angle (P < .0001). Post hoc pairwise comparisons indicated a significant decrease in shoulder abduction angle immediately after surgery compared to preoperative values (P < .0001) and a significant increase in shoulder abduction angle 6 weeks after the operation compared to immediately after surgery (P < .0065). However, shoulder abduction angle at 6 weeks remained significantly lower than preoperative values (P < .0001).
A significant decrease of 37.0° was observed between the preoperative measurement and the immediate postoperative period (P < .0001). Six weeks after surgery, the shoulder abduction angle remained significantly lower than the preoperative level by 29.83° (P < .0001). However, a significant increase of 7.17° was noted between the immediate postoperative measurement and the 6-week follow-up (P < .0065), indicating loss of tension of the anchor.
These findings confirm that shoulder abduction is significantly reduced immediately after surgery. The abduction angle remains significantly lower than preoperative levels, suggesting that the surgical treatment restored shoulder stability.
Hobbles were removed in all dogs. Physiotherapy was advised and started only for 2 dogs. For the dog with grade 2 lameness, meloxicam (0.1 mg/kg, PO) was prescribed for 2 weeks with a more gradual return to normal exercise.
Six months after the operation, all dogs had returned to full function. Only 1 dog had a persistent grade 1 thoracic limb lameness after exercise only. Shoulder stability remained satisfactory during the orthopedic examination. The dog with persistent lameness had a muscle atrophy. Physiotherapy was recommended for this dog. Unfortunately, the dog was lost to follow-up, and the owner did not return for an assessment. No complications or recurrences were observed during the study period.
Discussion
In the present study, all dogs with chronic thoracic limb lameness due to MSI surgically treated with the described minimally invasive ligamentoplasty using a scapular bone anchor and a humeral bone tunnel had a successful outcome 6 months after surgery, and all regained full function. All owners were informed of the novelty of this technique by means of an informed consent form, which they signed. Postoperative shoulder stability at short and long term was satisfactory in all animals, with excellent functional recovery in 5 dogs and good recovery in 1 dog (persistent grade 1 lameness). No complications were observed.
In this study, MSI was suspected based on clinical examination and diagnostic imaging findings and confirmed by arthroscopy. In all dogs, preoperative abduction angle was superior to 35°, which concurred with abduction angles reported in the literature for shoulders affected by MSI.30 As previously described in the literature,14,15 preoperative radiographs were unremarkable in all dogs except 1, which presented discreet signs of degenerative arthropathy and shoulder subluxation. This dog suffered from thoracic limb lameness for more than 2 months and had a history of severe trauma. Although not performed in our study, stress radiographs can also be taken to confirm the diagnosis of MGHL rupture as described by Livet et al.28
Ultrasonographic examinations of the shoulder joint were performed in all cases. This complementary examination is very useful to exclude other pathologies of the shoulder, to confirm the reason of the lameness, and to detect the presence of synovitis. All dogs in this study had synovial effusion on ultrasonographic examination. Ultrasonography of the medial compartment of the shoulder was performed in 5 dogs and showed an increase of the articular space as previously described.8 However, the tear of the MGHL was not visualized with this imaging modality. Magnetic resonance imaging (MRI) was not performed in our study as it was not available at our institution at the time of diagnosis. Nevertheless, MRI has shown great potential as a diagnostic tool for evaluating canine shoulder disease.31
In all dogs, after an arthroscopic exploration of the shoulder, the MGHL and the SST were damaged similarly as to what has been described in the literature.14,32,33
The tear of the cranial branch of the MGHL was the most frequently encountered lesion associated with SST lesions. When the MGHL is ruptured, Fujita et al34 demonstrated that villous reactions and vascularization in the SST and in the MGHL are more important. The authors also demonstrated that damage in the MGHL may trigger a process in which inflammation can lead to enzymatic breakdown of cartilage. These lesions are also exacerbated by weight bearing and repetitive motion and may result in shoulder instability over time.29
Several open techniques for surgical treatment of MSI have been described in veterinary medicine.12–17 While minimally invasive surgery is the gold standard in human medicine, an increasing number of minimally invasive procedures are reported in veterinary medicine, among which is arthroscopic surgery. Arthroscopy has many advantages. Indeed, it limits iatrogenic muscle damage, it promotes functional recovery while minimizing pain, it reduces surgical time, and it allows a complete visualization of all intra-articular damages.35
We used a video-assisted technique for MGHL reconstruction in our study. As in other studies25 reporting such technique, both arms of the MGHL were replaced by a single suture strand anchored at the level of the glenoid (between the origins of the 2 MGHL branches).
Even if anatomic reconstruction/replacement was not achieved, our technique led to a good functional outcome. Fujita et al34 have previously demonstrated that the cranial branch of the MGHL is much more responsible for stability than its caudal counterpart. Moreover, restoring the caudal arm of the MGHL is more technically challenging and requires an additional caudomedial port. Thus, placement of the anchor at the midway point is a good compromise.
Even though the principle of our technique is quite close to that described by O’Donnel et al,14 it does not require a lateral approach to the scapula, thus limiting dissections and especially the risk of infrascapular nerve injury. Nevertheless, it can be argued that placing an anchor is technically more difficult than drilling a bone tunnel.
An increase in the angle of abduction was noted between the postoperative and 8-week recheck. This initial loss of tension can be explained by several factors: elongation of the prosthesis, particularly at the node, and displacement of the anchor or widening of the tunnels. In the light of the radiographs, elongation of the prosthesis seems most likely. This loss of stability remains moderate and does not seem to influence functional recovery as the abduction angle remained within physiological values of less than 30°. Elongation of extra-articular stabilization remains a well-known and classic postoperative development, particularly in the stifle.36 This elongation is most likely due to knot tightening as it represents the weakest point of FiberTape.
In recent studies14,15 of shoulder stabilization, abduction angles at follow-up were not objectively reported, and no comparison could be made with our results.
Overall, at the time of final follow-up, 5 of 6 dogs (83%) had regained full function, whereas the remaining dog (17%) was determined to have an acceptable function. All dogs were companion animals, but 1 of the dogs participated in field trial competitions and was able to return to its activity after 12 weeks. In comparison, the use of an extracapsular prosthesis, such as the TightRope system (Arthrex) or surgical anchors,14 offers a success rate of over 90% in dogs, with a return to activity, including sports, typically observed between 16 and 20 weeks after surgery. The success of these techniques partly depends on strict control of immediate postoperative activity, including the use of a spica splint bandage for 4 to 16 weeks, combined with rehabilitation.
Our study was performed on a small number of animals and has several limitations, such as its retrospective nature and the lack of a control group. The video-assisted technique described remains challenging to perform and requires solid experience in arthroscopy.
Moreover, our results have not been compared to those of other stabilization techniques, and different anchors were used. Postoperative evaluations were only based on clinical examinations and radiographs. Computed tomography could have been performed to evaluate the quality of the bone anchoring and orientation of the implants as described in a previous study.25
In our study, the surgeon subjectively assessed the tension to apply on the sutures to reduce the instability.37 Further studies correlating the reduction of the abduction angle with the tension applied on the sutures would provide useful information as suggested by Llido et al.27 The surgeon’s experience is a key factor in our excellent results as this technique requires a great deal of arthroscopy knowledge and skill. Correct anchor placement and suture tension play a crucial role in preventing loosening. Inadequate surgical technique may result in insufficient fixation or premature loosening of the anchors.
Finally, with this technique, the SST was not repaired. It would be interesting to see whether a second bone tunnel with another anchor would enable repairing the SST and whether this has a real clinical impact on the recovery of shoulder stability.
In conclusion, this study showed that an arthroscopically guided ligamentoplasty technique with a medial scapula bone anchor and a humeral drilling tunnel was feasible and safe in dogs. The technique was effective in restoring shoulder abduction angles to their physiological levels and appeared to yield satisfactory clinical results according to our findings. All patient outcomes were considered successful.
Acknowledgments
None reported.
Disclosures
Thibaut Cachon, the primary author, is a consultant for Arthrex Vet Systems. The remaining authors have nothing to disclose.
No AI-assisted technologies were used in the composition of this manuscript.
Funding
The authors have nothing to disclose.
References
- 1.↑
Sidaway BK, McLaughlin RM, Elder SH, Boyle CR, Silverman EB. Role of the tendons of the biceps brachii and infraspinatus muscles and the medial glenohumeral ligament in the maintenance of passive shoulder joint stability in dogs. Am J Vet Res. 2004;65(9):1216–1222. doi:10.2460/ajvr.2004.65.1216
- 2.↑
Cogar SM, Cook CR, Curry SL, Grandis A, Cook JL. Prospective evaluation of techniques for differentiating shoulder pathology as a source of forelimb lameness in medium and large breed dogs. Vet Surg. 2008;37(2):132–141. doi:10.1111/j.1532-950X.2007.00364.x
- 3.↑
Franklin SP. Diagnosis of medial shoulder instability. Vet Comp Orthop Traumatol. 2019;32(6):v–vi. doi:10.1055/s-0039-1700556
- 4.↑
Bardet J. Diagnosis of shoulder instability in dogs and cats: a retrospective study. J Am Anim Hosp Assoc. 1998;34(1):42–54. doi:10.5326/15473317-34-1-42
- 5.↑
Pucheu B, Duhautois B. Surgical treatment of shoulder instability: a retrospective study on 76 cases (1993–2007). Vet Comp Orthop Traumatol. 2008;21(4):368–374. doi:10.3415/VCOT-07-06-0058
- 6.↑
Cook JL, Renfro DC, Tomlinson JL, Sorensen JE. Measurement of angles of abduction for diagnosis of shoulder instability in dogs using goniometry and digital image analysis. Vet Surg. 2005;34(5):463–468. doi:10.1111/j.1532-950X.2005.00070.x
- 7.↑
Barella G, Lodi M, Faverzani S. Ultrasonographic findings of shoulder teno-muscular structures in symptomatic and asymptomatic dogs. J Ultrasound. 2018;21(2):145–152. doi:10.1007/s40477-017-0271-4
- 8.↑
Gemignani F, Harel M, Livet V, et al. Pilot study of the ultrasonographic examination of the intact and transected medial glenohumeral ligament in dogs. Vet Radiol Ultrasound. 2023;64(2):306–313. doi:10.1111/vru.13164
- 9.↑
Porter I, Miller A, Jennings C, Frye C. Ultrasonographic approach to visualize the medial shoulder compartment and diagnose medial glenohumeral ligament and subscapularis lesions in dogs. J Am Vet Med Assoc. 2024;263(3):javma.24.08.0557. doi:10.2460/javma.24.08.0557
- 10.↑
Franklin SP, Devitt CM, Ogawa J, Ridge P, Cook JL. Outcomes associated with treatments for medial, lateral, and multidirectional shoulder instability in dogs. Vet Surg. 2013;42(4):361–364. doi:10.1111/j.1532-950X.2013.01110.x
- 11.↑
Woolley ELE, Collyer TA, Finch SJ, House AK. Medial shoulder instability: prevalence and treatment outcomes in 17 Poodles and 31 dogs of other breeds. VCOT Open. 2023;6(2):e107–e113. doi:10.1055/s-0043-1774372
- 12.↑
Cook JL, Tomlinson JL, Fox DB, Kenter K, Cook CR. Treatment of dogs diagnosed with medial shoulder instability using radiofrequency-induced thermal capsulorrhaphy. Vet Surg. 2005;34(5):469–475. doi:10.1111/j.1532-950X.2005.00071.x
- 13.↑
Fitch RB, Breshears L, Staatz A, Kudnig S. Clinical evaluation of prosthetic medial glenohumeral ligament repair in the dog (ten cases). Vet Comp Orthop Traumatol. 2001;14(4):222–228. doi:10.1055/s-0038-1632702
- 14.↑
O’Donnell EM, Canapp SO, Cook JL, Pike F. Treatment of medial shoulder joint instability in dogs by extracapsular stabilization with a prosthetic ligament: 39 cases (2008–2013). J Am Vet Med Assoc. 2017;251(9):1042–1052. doi:10.2460/javma.251.9.1042
- 15.↑
Hammer M, Grand JG. Inverted V-shaped extracapsular stabilisation technique and arthroscopic findings in six dogs with medial shoulder instability. J Small Anim Pract. 2021;62(9):795–804. doi:10.1111/jsap.13347
- 16.↑
Letesson J, Crumière A, Goin B. Long-term clinical outcome of medial shoulder instability in a dog treated with synthetic implant, cortical button, and interference screw. VCOT Open. 2024;7(1):e59–e68. doi:10.1055/s-0044-1787563
- 17.↑
Pettitt RA, Clements DN, Guilliard MJ. Stabilisation of medial shoulder instability by imbrication of the subscapularis muscle tendon of insertion. J Small Anim Pract. 2007;48(11):626–631. doi:10.1111/j.1748-5827.2007.00340.x
- 18.↑
Hoelzler MG, Millis DL, Francis DA, Weigel JP. Results of arthroscopic versus open arthrotomy for surgical management of cranial cruciate ligament deficiency in dogs. Vet Surg. 2004;33(2):146–153. doi:10.1111/j.1532-950X.2004.04022.x
- 19.↑
Kieves NR, Jones S. There is no superior treatment method for medial shoulder instability in dogs. Vet Evid. 2020;5(1). doi:10.18849/ve.v5i1.249
- 20.↑
Phipps WB, Solano MA. Functional outcomes of dogs undergoing shoulder arthrodesis with 2 locking compression plates. Vet Surg. 2023;52(2):266–275. doi:10.1111/vsu.13900
- 21.↑
Fitzpatrick N, Yeadon R, Smith TJ, et al. Shoulder arthrodesis in 14 dogs. Vet Surg. 2012;41(6):745–754. doi:10.1111/j.1532-950X.2012.01004.x
- 22.↑
John R, Wong I. Innovative approaches in the management of shoulder instability: current concept review. Curr Rev Musculoskelet Med. 2019;12(3):386–396. doi:10.1007/s12178-019-09569-z
- 23.
Zhang AL, Montgomery SR, Ngo SS, Hame SL, Wang JC, Gamradt SC. Arthroscopic versus open shoulder stabilization: current practice patterns in the United States. Arthroscopy. 2014;30(4):436–443. doi:10.1016/j.arthro.2013.12.013
- 24.↑
Chalmers PN, Mascarenhas R, Leroux T, et al. Do arthroscopic and open stabilization techniques restore equivalent stability to the shoulder in the setting of anterior glenohumeral instability? A systematic review of overlapping meta-analyses. Arthroscopy. 2015;31(2):355–363. doi:10.1016/j.arthro.2014.07.008
- 25.↑
Penelas A, Gutbrod A, Kühn K, Pozzi A. Feasibility and safety of arthroscopic medial glenohumeral ligament and subscapularis tendon repair with knotless anchors: a cadaveric study in dogs. Vet Surg. 2018;47(6):817–826. doi:10.1111/vsu.12929
- 26.↑
Rocheleau PJ, Holz KA, Peura AH. Ex vivo evaluation of arthroscopically assisted shoulder stabilization in dogs using an intra-articular aiming device. Vet Surg. 2023;52(4):564–574. doi:10.1111/vsu.13935
- 27.↑
Llido M, Livet V, Carozzo C, Viguier É, Cachon T. Treatment of medial shoulder joint instability by stabilization with an arthroscopically guided prosthetic ligament: a cadaveric feasibility study in dogs. Vet Comp Orthop Traumatol. 2023;36(1):1–9. doi:10.1055/s-0042-1744174
- 28.↑
Livet V, Harel M, Taroni M, et al. Stress radiography for the diagnosis of medial glenohumeral ligament rupture in canine shoulders. Vet Comp Orthop Traumatol. 2019;32(6):433–439. doi:10.1055/s-0039-1692469
- 29.↑
Outerbridge RE. The etiology of chondromalacia patellae. J Bone Joint Surg Br. 1961;43–B(4):752–757. doi:10.1302/0301-620X.43B4.752
- 30.↑
Jones SC, Howard J, Bertran J, et al. Measurement of shoulder abduction angles in dogs: an ex vivo study of accuracy and repeatability. Vet Comp Orthop Traumatol. 2019;32(6):427–432. doi:10.1055/s-0039-1692410
- 31.↑
Murphy SE, Ballegeer EA, Forrest LJ, Schaefer SL. Magnetic resonance imaging findings in dogs with confirmed shoulder pathology. Vet Surg. 2008;37(7):631–638. doi:10.1111/j.1532-950X.2008.00429.x
- 32.↑
Devitt CM, Neely MR, Vanvechten BJ. Relationship of physical examination test of shoulder instability to arthroscopic findings in dogs. Vet Surg. 2007;36(7):661–668. doi:10.1111/j.1532-950X.2007.00318.x
- 33.↑
Kennedy EJ, Corriveau KM, Wilhite R. Evaluation of canine shoulder arthroscopy for anatomical and safety considerations. Vet Comp Orthop Traumatol. 2024;37(4):181–188. doi:10.1055/s-0044-1779497
- 34.↑
Fujita Y, Yamaguchi S, Agnello KA, Muto M. Effects of transection of the cranial arm of the medial glenohumeral ligament on shoulder stability in adult Beagles. Vet Comp Orthop Traumatol. 2013;26(2):94–99. doi:10.3415/VCOT-12-03-0034
- 35.↑
Tan CK, Guisasola I, Machani B, et al. Arthroscopic stabilization of the shoulder: a prospective randomized study of absorbable versus nonabsorbable suture anchors. Arthroscopy. 2006;22(7):716–720. doi:10.1016/j.arthro.2006.03.017
- 36.↑
Tinga S, Kim SE, Banks SA, et al. Femorotibial joint kinematics in nine dogs treated with lateral suture stabilization for complete cranial cruciate ligament rupture. J Am Vet Med Assoc. 2021;258(5):493–501. doi:10.2460/javma.258.5.493
- 37.↑
Dunn AL, Buffa EA, Marchevsky AM, Heller J, Moores AP, Farrell M. Inter- and intra-operator variability associated with extracapsular suture tensioning: an ex vivo study. Vet Comp Orthop Traumatol. 2012;25(06):472–477. doi:10.3415/VCOT-11-12-0189
