Medial Patellar Luxation in a Middle-Aged Small Breed Dog
Adrianna M Sage, DVM, MS, cVMA, DACVAA
Dr. Adrianna Sage with “Bindo”
Abstract
An approximately 7–8-year-old male castrated small mixed breed dog presented for non-weightbearing of his left pelvic limb while ascending and descending stairs. A grade 1-2 medially luxating patella of the left pelvic limb was diagnosed with secondary myofascial restriction of the contralateral limb, lumbar spinous region, and caudal cervical/cranial thoracic region. Treatment included four sessions of a combination of dry needling (GV20, cervical spinal points, GV14, SI11, SI12, BL21-23, GV4, GB29, GB30, BL54, ST34, ST36, SP9, SP10, GB34, Bai Hui) and electroacupuncture followed by massage, with laser therapy added to the final session. Gradual improvement in myofascial restriction and mobility was observed, and after the fourth treatment session, he showed significant improvement in his pelvic limb range of motion and would rarely hold his affected limb up only while descending stairs.
History of Present Illness and Chief Complaint
Bindo is an approximately 7- to 8-year-old male castrated terrier cross who presented for an ongoing history of non-weight bearing in his left pelvic limb only when ascending or descending stairs. Bindo was adopted by his current owners from the Humane Society in 2018. He had been found on the streets in Texas and was treated for heartworm disease just prior to his adoption. He has been otherwise healthy with no history of trauma since adoption. He walks, runs, plays, and jumps onto the furniture at home without any difficulty and goes for half to one mile or more walks daily. Since adoption, he has always lifted his left pelvic limb when descending stairs and occasionally when ascending. He will also use both hind limbs to hop up the stairs. Bindo currently receives Cosequin DS (glucosamine 500 mg, sodium chondroitin sulfate 400 mg, manganese 3 mg) once daily and Trazodone 25-50 mg as needed for anxiety. He also receives heartworm/flea/tick prevention.
Physical Examination and Clinical Assessments
On initial physical exam findings, Bindo had a normal body condition score (5/9) and some moderate dental calculus and gingivitis but was otherwise in good health. His neurologic exam revealed mild intermittent kyphosis of his lumbar spine, a slightly shortened bilateral pelvic limb stride with rare skip/hop of his left hind when ambulating on a flat surface, but no ataxia. While ascending stairs, both of his pelvic limbs were utilized to hop up to each step, and while descending, he held his left pelvic limb up and was completely non-weight bearing on it. An orthopedic exam revealed discomfort on caudal extension of his right shoulder, reduced extension bilaterally in the coxofemoral joints, with left worse than the right, and a grade 1-2 out of 4 medial patellar luxation (MPL) of his left pelvic limb. There was no obvious cranial drawer sign, swelling, or crepitus of the left stifle and he had no difficulties going from a sitting to standing position or vice versa.
Myofascial exam: Taut ropey bands bilaterally mid to caudal cervical muscles, especially within the omotransversarius muscles. Pectoral muscles taut bilaterally with multiple trigger points and ropey bands extending caudodorsally into both shoulder regions (right worse than left). There was no discomfort over his thoracolumbar spine, but some palpable restriction was present in the thoracolumbar region. In the pelvic limbs, the right quadricep muscle group was taut and bilaterally the semimembranosus and semitendinosus muscles had ropey bands that were uncomfortable with deeper manipulation. The left medial proximal pelvic limb muscles (specifically sartorius, vastus medialis, pectineus, and gracilis muscles) were tense and very uncomfortable during palpation.
Problem List
Left hind limb lameness, mainly when descending stairs
Decreased range of motion (ROM) in hips bilaterally (left > right)
Intermittent kyphosis of lumbar spine
Mild gait abnormalities in pelvic limbs (shortened stride, rare hop/skip left hind)
Discomfort in right shoulder region
Myofascial restriction of neck and cranial chest, shoulders, lumbar spine, and pelvic limbs
Dental disease
Differential Diagnoses
Left hind limb lameness: Vascular – femoral head necrosis (Legg-Calvé-Perthes disease), thrombosis, ischemic myelopathy (FCEM); Infectious/inflammatory – Borrelia burgdorferi (Lyme disease), rickettsial infection; Neoplasia – osteosarcoma, nerve sheath tumor, chondrosarcoma, synovial cell sarcoma; Degenerative – degenerative joint disease of hip/stifle/hock, cranial cruciate ligament (CCL) disease, intervertebral disc disease; Iatrogenic/intoxication – unknown prior surgical complications; Congenital – medial patellar luxation, osteochondrosis dissecans, hip dysplasia; Autoimmune – immune-mediated polyarthritis, hypertrophic osteodystrophy; Trauma – meniscal tear, CCL rupture, intervertebral disc disease, femoral head fracture, hip/tarsal luxation, metatarsal fracture(s), torn toenail, previous injury to limb (hit by a car, animal fight, abuse, etc.); Endocrine/metabolic – hypothyroidism, diabetes mellitus; Myofascia – muscle or ligament strain/inflammation (iliopsoas, sartorius, quadriceps, tensor fascia lata, adductors, gracilis, pectineus, piriformis, hamstrings), sciatic nerve entrapment, myofascial trigger points.
Decreased ROM hips: Vascular – femoral head necrosis (Legg-Calvé-Perthes disease); Infectious/inflammatory – diskospondylitis, Borrelia burgdorferi (Lyme disease), rickettsial infection; Neoplasia – osteosarcoma, nerve sheath tumor, chondrosarcoma, synovial cell sarcoma; Degenerative – degenerative joint disease of hips, intervertebral disc disease L-S region; Iatrogenic/intoxication – unknown prior surgical complications (e.g. FHO); Congenital –osteochondrosis dissecans, hip dysplasia; Autoimmune – immune-mediated polyarthritis, myositis; Trauma –intervertebral disc disease, femoral head fracture, hip luxation, cauda equina syndrome, previous injury to limb (hit by a car, animal fight, abuse, etc.); Endocrine/metabolic – hypothyroidism, diabetes mellitus; Myofascia – muscle or ligament strain/inflammation (epaxials, gluteals, iliopsoas, psoas minor, semimembranosus/tendinosus, biceps femoris, sartorius, gracilis, internal/external obturator, quadrate), myofascial trigger points.
Putative/Definitive Diagnosis
The most likely cause of Bindo’s left hind limb lameness, decreased ROM in his hips, discomfort of his right shoulder, and myofascial restriction is a grade 1-2 medial patellar luxation of the left hind limb with myofascial strain patterns associated with postural and gait compensation.
Cannot fully rule out other differentials without further diagnostics, however, given the patient’s signalment, health status, minor discomfort, length of intermittent lameness without progression, and otherwise normal physical examination findings, it is unlikely that the underlying condition would be vascular, infectious/inflammatory, neoplastic, metabolic, or autoimmune in origin. There is also no known history of trauma or previous surgical intervention, however, the patient’s history prior to his adoption is unknown. Degenerative joint disease of the left stifle, hip, or tarsus is possible and would require radiographs for further exploration, however, Bindo does not exhibit any pain on manipulation of the stifle or tarsus and has only minor discomfort on caudal extension of his hips. A left CCL rupture also seems unlikely due to his lameness mainly becoming present while using stairs and resolving immediately after and the lack of a cranial drawer sign, but a partial tear cannot be completely ruled out.
Medical Decision Making
Further staged diagnostics including pelvic and stifle radiographs +/- computed tomography (CT) and/or magnetic resonance imaging (MRI) were discussed to evaluate for the presence or absence of osteoarthritis and other co-morbidities of the spine, hips, and pelvic limbs in addition to the MPL. Bloodwork was also recommended to evaluate for underlying metabolic comorbidities. Given the chronicity of the problem, his otherwise good health, and the low grade of his left hind MPL, Bindo’s owner elected to first try a conservative approach involving a combination of acupuncture, massage, and photobiomodulation with the overall goal of improving ROM in hind limbs and improve usage of his left pelvic limb.
Medical Acupuncture and Related Techniques Used
An initial plan of massage over myofascially restricted areas followed by dry needling was chosen to allow Bindo to acclimatize to treatment. In subsequent visits, electroacupuncture (EA) and low-level laser therapy were added as deemed necessary.
Visit 1 (3/03/2022)
Massage: A combination of effleurage and petrissage was used over Bindo’s neck and shoulder regions, focusing on the lateral neck muscles (splenius, ventral cervical serratus, omotransversarius and chleidobrachialis muscles), cranial chest (sternocephalicus, brachiocephalicus, and pectoralis muscles), trapezius, deltoids, and supra- and infra-spinatus muscles. This was continued caudally along the epaxial and hypaxial muscles, over the hips and thighs bilaterally. Gentle petrissage was also focused over the left sartorius, vastus medialis, pectineus, and gracilis muscles where he had been uncomfortable. His owner was given direction on how to perform light massage at home.
Acupuncture: Seirin J Type 0.16 x 30 mm needles with guide tubes. Points used: GV20, GV14, Bai Hui – parasympathetic and CNS stimulation; cervical spinal points bilateral – CNS and localized trigger points; GV4 – CNS for T-L region; ST36 bilateral – autonomic modulation and peripheral stimulation of fibular nerve; ST34, BL54, GB 34 – peripheral stimulation of femoral, sciatic, and fibular nerves, respectively.
Visit 2 (3/17/2022)
Initial massage was performed as previously described, followed by dry needling at GV14/20, cervical spinal points, and Bai Hui using Seirin J Type 0.16 x 30 mm needles. BL40 (LH) was added for tibial nerve stimulation, and SI11/12 for localized trigger points within the infra- and supra-spinatus muscles on the right shoulder.
Additionally, electroacupuncture (EA) was used at ST34 to ST36 on the left hind, and SP9 to SP10 (peripheral stimulation of tibial and saphenous nerves as well as autonomic modulation) on the right hind using an AWQ-104L unit on dense-disperse mode with low frequency at 5 Hz and high frequency at 68 Hz; intensity set to 1.5 for both. The EA treatments were performed using Acurea Eco spring handle 0.16 x 15mm needles with guide tube. Treatment was approximately 15 minutes.
Visit 3 (4/06/2022)
Massage, dry needling, and EA were performed as per the previous visit.
Visit 4 (5/25/2022)
Given that it had been seven weeks since his last treatment, Bindo was showing some signs of myofascial restriction again in both pelvic limbs and his ROM in his right hip was reduced. Dry needling at GV14/20, BL21-23 bilaterally (CNS T-L spine), a couple pf localized trigger points within the shoulder region, Bai Hui, ST36 bilaterally, and GB29/30 plus BL54 (localized hip restriction and peripheral sciatic nerve stimulation) on the right using Seirin J Type 0.16 x 30 mm needles left in place for approximately 20 minutes. This was followed by photobiomodulation therapy of the hips and stifles bilaterally using a Class IV Companion Animal Therapy Laser utilizing the preset protocols for hips and stifles (Hips – 800J total at 5W for 3 minutes and 20 seconds [continuous for 110s, then 10Hz pulsed for 60s, then 500Hz for 30s]; Stifle – 1200J total at 6W for 4 minutes and 10 seconds [continuous for 160s, then 10Hz pulsed for 40s, then 500Hz for 50s]).
Outcomes, Insights, Discussion
Bindo received four treatments over a course of two-and-a-half months, with approximately two weeks between each of the first three treatments and the fourth treatment seven weeks later. More frequent treatments (weekly) may have been beneficial initially, however, scheduling constraints did not allow for this.
Bindo improved significantly after his first treatment. His owner reported that he was more active, and she noticed him using his left hind limb more when taking the stairs. At his second treatment, his myofascial exam revealed less restricted movement and discomfort, especially in his hind limbs. He was no longer uncomfortable on extension of his right forelimb but there were still a few localized trigger points within the right infra- and supra-spinatus muscles. During gait evaluation after his third treatment, Bindo’s stride appeared improved, and he was now using his left hind limb most of the time while descending stairs.
Acupuncture along with adjunct therapies appeared to help relieve Bindo of a lot of his myofascial restriction that had likely developed over time related to compensatory factors from his left MPL. While other underlying causes of restriction and discomfort cannot be ruled out, a commonly diagnosed disease, osteoarthritis, would also be similarly managed. In Bindo’s case, acupuncture is suspected to have provided local relief of myofascial trigger points and result in modulation of the pain pathway at the level of the spinal cord and brain by stimulation of peripheral and spinal nerves. Additionally, Bindo was relaxed, and his anxiety reduced by the addition of GV20 and GV14, possibly with the assistance of ST36, to modulate the autonomic nervous system.
References
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