Peroneus quartus: prevalance and clinical importance

An atlas of anatomical variants of the human calcaneus

The usefulness of anatomical variation is determined by the knowledge of why nonmetric traits appear. Clear descriptions of the traits are a necessary task, due to the risk of confusing anatomical variants and evidence of trauma. Numerous interpretations of the appearance of calcaneal anatomical variants add to the need of an anatomical atlas of calcaneal nonmetric traits. We have analyzed a total of 886 calcanei; 559 belong to different modern and pre-Hispanic samples, and 327 bones were studied from a reference collection from Athens. In this study, we present the anatomical variations that exist on the calcaneus bone, some of which have rarely been mentioned in previous research. The standardization of methods proposed may be useful to experts working in human anatomy, physical anthropology as well as comparative morphology, due to usefulness of this information during surgery, and bioanthropology to observe and study the lifestyle of past populations.

Direct Observation of a Single Peroneal Myotendinous Unit Anatomic Variant: A Case Report and Systematic Review

CASE

A 29-year-old woman with acute peroneal tendon subluxation underwent superior retinacular repair. On exposure, a single peroneal myotendinous unit was encountered, as opposed to the usual presence of independent peroneal tendons arising from separate muscle bellies. At 3-year follow-up, she has had no recurrence with full return to activity and no limitations.

CONCLUSION

Multiple peroneal myotendinous variants have been described; however, this report is the first to describe direct intraoperative observation of a single peroneal myotendinous unit. Whether this anatomic variant contributed to the patient's problem or has other potential clinical sequelae remains to be elucidated.

Imaging of Tendinous and Muscular Anatomical Variants Around the Ankle

Tendinous and muscular anatomical variants around the ankle are usually an unexpected finding on imaging. Magnetic resonance imaging offers the best visualization of the accessory muscles; however, they can also be detected on radiography, ultrasonography, and computed tomography. Their accurate identification facilitates appropriate management of the rare symptomatic cases, mostly caused by accessory muscles in the posteromedial compartment. Symptomatic patients present with chronic ankle pain, most commonly as tarsal tunnel syndrome. The most frequently observed accessory muscle around the ankle is the peroneus tertius muscle, an accessory muscle in the anterior compartment. The tibiocalcaneus internus and peroneocalcaneus internus are uncommon; anterior fibulocalcaneus is rarely mentioned. We describe the anatomy of the accessory muscles with their anatomical relations accompanied by schematic drawings and radiologic images from clinical practice.

Anatomical Factors Which Influence the Formation of Peroneal Tendon Tears: A Retrospective Comparative Study

This study aims to investigate the anatomical factors that are effective in the formation of peroneal tendon tears comparing with the control group. The patients with ankle magnetic resonance imaging (MRI) due to pain on the lateral side of the ankle were retrospectively analyzed using the clinical archive between July 2015 and January 2020. Peroneal tendon tears, peroneal tubercle type and size, presence of peroneal quartus, presence and type of retromalleolar groove, retromalleolar groove area, lateral malleolus type, presence of os peroneum, peroneus brevis-lateral malleolus distance (PBLMD), and accompanying pathologies in coronal, axial, and sagittal planes MRI were evaluated. PBLMD was measured as 27.1 ± 12.3 mm in Group 1. With PBLMD, it was measured as 39.6 ± 11.68 mm in Group 2. There was a significant relationship between low-lying peroneus brevis muscle and peroneal tear (p < .001). Peroneal tendon tear was more common in patients with peroneal quartus muscle (p < .001). There was a relationship between the retromalleolar groove type and the presence of peroneal tear (p = .004). More peroneal tears were observed in the concave retromalleolar groove type. The presence of concave type retromalleolar groove, peroneus quartus, and low-lying peroneus brevis muscle was found to be associated with peroneal tendon tears.

Importance of Space-Occupying Anatomical Variations in Peroneal Tendoscopy

BACKGROUND

We hypothesized that peroneal tendons disorders are more commonly associated with anatomical variations, which could overcrowd the retrofibular groove.

METHODS

This single-center retrospective case study covered 84 consecutive cases that had undergone peroneal tendoscopy. Peroneal tendoscopy was performed on 82 patients, predominantly female (3:1) with a median age of 46 years. The preoperative evaluation and all the procedures were performed by a single surgeon using a standardized technique.

RESULTS

Two patients required revision surgery 8 and 52 months after the index procedure due to persistent posterolateral ankle pain. Peroneal tendoscopy was performed as a solitary procedure in 45.1% (37/82) of cases, while the remaining cases involved peroneal tendoscopy as a supplementary procedure. Low-lying peroneus brevis muscle belly (LLMB) was the most common finding in this series in 53.7% (44/82) of cases. In 41.5% (34/82) of cases, longitudinal tears of the peroneus brevis tendon were noted. Some patients presented with more than 1 concomitant peroneal tendon pathology. The LLMB was observed in 23.5% (8/34) of cases with a longitudinal tear of the peroneus brevis tendon.

CONCLUSION

Peroneal tendon anatomical variations, especially LLMB, were associated with the presence of peroneus brevis tendon ruptures and intrasheath peroneal tendon subluxations as well as posttraumatic posterolateral ankle pain. Due to high rates of undiagnosed and misdiagnosed cases of LLMB preoperatively, we believe special care should be taken to recognize it during tendoscopy. Peroneal tendoscopy is a high-efficiency, low-complication method to treat some peroneal tendon conditions.

LEVEL OF EVIDENCE

Level IV, case series.

Fibularis Intersection Syndrome: A Rare Cause of Lateral Foot Pain in Runners

ABSTRACT

Running is a common cause of foot and ankle injuries. Accurate diagnosis is important for appropriate management to resolve the issue. For clarity of diagnoses, the physician should be able to perform a thorough physical examination in conjunction with point-of-care ultrasound. The authors report a case study of a young male runner with lateral ankle pain. Based on clinical assessment and point-of-care ultrasound, a diagnosis of fibularis intersection syndrome was proposed. This type of injury can be treated with graded eccentric loading of fibularis tendons and proprioceptive exercises. This case report highlights the importance of point-of-care ultrasound to determine the appropriate diagnosis and management.

Accessory Flexor Hallucis Longus Tendon Discovered During Achilles Tendon Reconstruction: A Report of 2 Cases

CASE

We present 2 cases of Achilles reconstruction using flexor hallucis longus (FHL) tendon transfer for the augmentation of Achilles surgical repair during which the patients were noted to have accessory FHL tendons. Structure identification in the posterior ankle is important because the neurovascular bundle is in close proximity to the FHL; knowledge of the anatomy of variations is helpful, and 2 cases of accessory tendon variation are reported.

CONCLUSIONS

Achilles tears are typically primarily repaired. Some patients may require augmentation with allograft or autograft transfer of the FHL tendon. Accessory FHL tendons discovered during posterior approach to the Achilles has not been described in the literature.

Bilaterally Variant Accessory Fibularis Muscle: Its Phylogenetic, Molecular and Clinical Perspective

Accessory fibularis muscle is prevalent in 2.9-21.8% of the world population. Incidentally during routine dissection of a 75-year-old male cadaver, bilaterally accessory fibularis muscle was observed. On both the sides, proximal site of attachment was same but muscle displayed different distal sites of insertion in the foot. Appearance of accessory muscle in the leg is indicative towards the ongoing phylogenetic evolution operating at the molecular level. Bio-mechanical advantage of this variant muscle is the additional support provided to the subtalar joint. Also it acts as synergist to fibularis longus and brevis during eversion of the foot. Clinically this muscle may predispose to chronic ankle pain, dislocation of peroneal tendons from retromalleolar groove and post fracture dislocation in foot. Wide range of accessory fibularis muscle has been previously reported with different nomenclature, however, existence of two different variants in same cadaver has been rarely reported. The current observation is significant for clinicians to acknowledge when evaluating and operating patients with foot disorders.

Back to the roots of rheumatology - Imaging of regional pain syndromes

Musculoskeletal regional pain syndromes (RPS) often lead to patient referrals in general and rheumatological practice. Detailed history taking and clinical examination can, in most cases, reveal the cause for pain and direct the subsequent management of the conditions. Yet, when in doubt, imaging methods, such as ultrasound (US) may support the clinical assessment. This paper reviews the underlying pathologies of some of the most frequently encountered RPS and the role of musculoskeletal US imaging for their diagnosis and treatment. If available, data on diagnostic accuracy and comparisons with gold standards are reported. The article stresses the importance of anatomical and sonoanatomical knowledge for the proper interpretation of the US images, points out the advantages and disadvantages of this imaging tool, and suggests the future research agenda.

Endoscopic Resection of Peroneus Quartus

The peroneus quartus is the most common supernumerary muscle of the foot and ankle. It can be symptomatic and associated with splits or tears in the peroneus brevis, subluxation or dislocation of the peroneal tendon, tendinous calcification, chronic peroneal compartment syndrome, and painful hypertrophy of the retrotrochlear eminence. The purpose of this Technical Note was to describe the details of endoscopic resection of the peroneus quartus. This technique has the advantages of better cosmetic results, less pain, less surgical trauma, and the possibility of dealing with associated pathologies endoscopically.

Unusual accessory peroneal muscles, peroneus quartus, peroneus digiti quinti, and their association with peroneus brevis tendon tear

Background

Anatomic variation and supernumerary contents in the superior peroneal tunnel, and the prominence of the retrotrochlear eminence and peroneal tubercle are related to peroneal tendon disorders.

Objectives

To investigate the prevalence, origin, and insertion of accessory peroneal muscles, the prominence of the retrotrochlear eminence and peroneal tubercle, and their association with peroneal tendon tears.

Methods

We examined 109 formalin-embalmed legs of cadavers from Thai donors. Accessory peroneal muscles and peroneal tendon tears were noted. Associations with peroneal tendon tears were evaluated using a χ2 test.

Results

We found 48 accessory peroneal muscles comprising 13 peroneus quartus (PQ), 33 peroneus digiti quinti (PDQ), and 2 unusual muscles. All PDQ originated from the PB tendon and inserted on various parts of the 5th toe. The PQ originated mostly from the PB muscle belly and less from the tendinous part with various insertions on the retrotrochlear eminence, peroneal tubercle, cuboid, and dorsolateral surface of the 5th metatarsal base. Two unusual accessory muscles were identified, 1 coexisting with the PQ. A PB tendon tear was found in 13% of specimens. We found no association between the peroneal tendon tears and the accessory peroneal muscles, or prominence of the retrotrochlear eminence or peroneal tubercle.

Conclusions

The prevalence of PQ, PDQ, and unusual accessory peroneal muscles was concordant with previous findings. We noted a new type of unusual accessory peroneal muscle coexisting with the PQ. No association was found between peroneal tendon tears and the PQ, PDQ, or prominence of the retrotrochlear eminence or peroneal tubercle.

The peroneus longus muscle and tendon: a review of its anatomy and pathology

This article will review the anatomy and common pathologies affecting the peroneus longus muscle and tendon. The anatomy of the peroneus longus is complex and its long course can result in symptomatology referable to the lower leg, ankle, hindfoot, and plantar foot. Proximally, the peroneus longus muscle lies within the lateral compartment of the lower leg with its distal myotendinous junction arising just above the level of the ankle. The distal peroneus longus tendon has a long course and makes two sharp turns at the lateral ankle and hindfoot before inserting at the medial plantar foot. A spectrum of pathology can occur in these regions. At the lower leg, peroneus longus muscle injuries (e.g., denervation) along with retromalleolar tendon instability/subluxation will be discussed. More distally, along the lateral calcaneus and cuboid tunnel, peroneus longus tendinosis and tears, tenosynovitis, and painful os peroneum syndrome (POPS) will be covered. Pathology of the peroneus longus will be illustrated using clinical case examples along its entire length; these will help the radiologist understand and interpret common peroneus longus disorders.

Measuring Visualized Tendon Length in Peroneal Tendoscopy

BACKGROUND

Despite multiple studies outlining peroneal tendoscopy, no study exists to evaluate how effective tendoscopy is at visualizing the peroneal tendons without missing a lesion. We sought to measure the length of the peroneal tendons that could be visualized using tendoscopy.

METHODS

Ten fresh cadaveric specimens were evaluated using standard peroneal tendoscopy techniques. Peroneus longus and brevis tendons were pierced percutaneously with Kirschner wires at the edge of what could be seen through the camera. The tendon sheaths were then dissected and the distances from anatomic landmarks were directly measured. During zone 3 peroneus longus tendoscopy, a more distal portal site was created for the final 5 specimens.

RESULTS

The peroneus brevis could be visualized through the entirety of zone 1 and up to an average of 19.5 mm (95% confidence interval, 16.5-22.5) from its insertion onto the base of the fifth metatarsal in zone 2. Peroneus longus could be visualized through the entirety of zones 1 and 2 and up to an average of 9.7 mm from its insertion onto the base of the first metatarsal in zone 3. This distance was decreased significantly with a more distal portal. The muscle belly of peroneus brevis terminated an average of 1.8 mm (-3.7 to 7.3) above the tip of the lateral malleolus.

CONCLUSIONS

Despite limitations, these results suggest that the vast majority of the length of the peroneal tendons can be seen during routine peroneal tendoscopy. A more distal skin portal site may improve visualization of zone 3 of peroneus longus.

CLINICAL RELEVANCE

This study confirms the ability of peroneal tendoscopy to see the entire tendon length with appropriate portal placement.

Peroneal tendon disorders

Pathological abnormality of the peroneal tendons is an under-appreciated source of lateral hindfoot pain and dysfunction that can be difficult to distinguish from lateral ankle ligament injuries.

Enclosed within the lateral compartment of the leg, the peroneal tendons are the primary evertors of the foot and function as lateral ankle stabilisers.

Pathology of the tendons falls into three broad categories: tendinitis and tenosynovitis, tendon subluxation and dislocation, and tendon splits and tears. These can be associated with ankle instability, hindfoot deformity and anomalous anatomy such as a low lying peroneus brevis or peroneus quartus.

A thorough clinical examination should include an assessment of foot type (cavus or planovalgus), palpation of the peronei in the retromalleolar groove on resisted ankle dorsiflexion and eversion as well as testing of lateral ankle ligaments.

Imaging including radiographs, ultrasound and MRI will help determine the diagnosis. Treatment recommendations for these disorders are primarily based on case series and expert opinion.

The aim of this review is to summarise the current understanding of the anatomy and diagnostic evaluation of the peroneal tendons, and to present both conservative and operative management options of peroneal tendon lesions.

Cite this article: EFORT Open Rev 2017;2:281-292. DOI: 10.1302/2058-5241.2.160047

Arthroscopic Taloplasty for an Anterolateral Snapping Ankle

Anterior ankle snapping syndrome is rare. Snapping of the extensor digitorum longus due to attenuated inferior extensor retinaculum and snapping due to hypertrophied or low-lying peroneal tertius muscle have been reported. We reported a new mechanism of anterolateral snapping due to a hypertrophied talar head. Anterolateral snapping ankle can be revealed by active dorsiflexion and plantarflexion of the ankle with the foot inverted. Foot inversion will tension the inferior extensor retinaculum and uncover the dorsolateral prominence of the talar head. The dorsolateral prominence of the talar head will snap over the proximal edge of the inferior extensor retinaculum. This technical note reports the technique of arthroscopic contouring of the talar head via extra-articular ankle arthroscopy. We named this technique arthroscopic taloplasty.

The Peroneus Quartus Muscle in a Locking Phenomenon of the Ankle: A Case Report

We present the case of a 64-year-old female who was referred to us with an unexplained clicking and locking phenomenon of the right ankle. The magnetic resonance imaging findings suggested a longitudinal tear of the peroneus brevis tendon. During tendoscopy, not only was a Raikin type B intrasheath tendon subluxation visible, but also a peroneus quartus muscle. The peroneus brevis tear was tubularized and the peroneus quartus muscle resected, which resolved the patient's complaints.

Dynamic ultrasound of peroneal tendon instability

Ankle snapping may be caused by peroneal tendon instability. Anterior instability occurs after traumatic superior peroneal retinaculum injury, whereas peroneal tendon intrasheath subluxation is atraumatic. Whereas subluxation is mainly dynamic, ultrasound allows for the diagnosis and classification of peroneal instability because it allows for real-time exploration. The purpose of this review is to describe the anatomic and physiologic bases for peroneal instability and to heighten the role of dynamic ultrasound in the diagnosis of snapping.

The variations of peroneus digiti quinti muscle and its contribution to the extension of the fifth toe. A cadaveric study

Objectives:

To investigate the origin, prevalence, and possible effects of peroneus digiti quinti muscle (PDQ) on the fifth toe, to find out the variations of PDQ by determining the relationship between peroneus brevis muscle (PB) and PDQ, and to reveal its importance for the applications in foot and ankle surgery.

Methods:

This study was conducted at the Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey between September 2013 and June 2014. The study was a prospective dissection of cadaveric lower limbs. Twenty-five amputated lower limbs were stored in the freezer at -15°C. The legs were dissected; prevalence and variations of peroneus digiti quinti were investigated.

Results:

Peroneus digiti quinti muscle was found in 8 (32%) of 25 dissected lower limbs. However, 2 different tendon extensions were found at 3 (37.5%) of 8, and 5 (62.5%) of them were determined to have a single tendon.

Conclusion:

The incidence, dimensions, length, and insertions of peroneus digiti quinti are important in the evaluation and treatment of functional loss of the fifth toe, lateral foot deformities, and tendon problems behind the lateral malleolus of the ankle.

The accessory peroneal (fibular) muscles: peroneus quartus and peroneus digiti quinti. A systematic review and meta-analysis

The denomination of "accessory peroneal muscle" (APM) refers usually to two muscles: the peroneus quartus (PQua) and the peroneus digit quinti (PQui) which were believed to be variants of a same muscle. Their morphology and prevalence show high variation in relevant literature mainly owing to the diverse terminology used to describe this muscle group. The aim of this meta-analysis is to generate more accurate description and frequency of those muscles. A total of 46 studies (3,928 legs/ankles) met the inclusion criteria. The aggregate results were: (a) a true APM prevalence of 16 % with 10.2 % for PQua vs. 34.3 % for PQui; (b) a crude prevalence of 16.6 % for PQua vs. 21.5 % for PQui; (c) a bilateral prevalence of 1.73 % for PQua vs. 12.5 % for PQui; (d) the PQua was significantly more prevalent in Indian populations compared to all other ancestries, and the PQui is significantly more prevalent in Europeans and Americans compared to Japanese and Korean populations; (e) though a tendency for higher frequency was found in males and on the right specimens, no significance was found for gender and side; for (f) the "surgical" occurrence of PQua in studies dealing with peroneal tendon surgery was 5.5 % where peroneal tendon pathology seems to be not associated with the presence of an APM; (g) the MRI prevalence of APM was 10.6 %; (h) APMs took origin from peroneus brevis in 60 %, from the distal fibula in 36 % and from other structures in 4 %; (i) APMs took insertion on retrotroclear eminence of the calcaneum in 53.4 %, on peroneal trochlea in 6.6 %, merged with a peroneal tendon in 9.3 %, and inserted on the extensor apparatus of the 5th toe in 18.4 %. Despite the acknowledged limitation owing to the varied terminology used to describe this accessory muscle group, the significant differences found between the aggregate frequency estimates of each muscle do not support the hypothesis that both muscles are variants of a same structure.

Unusual fibularis (peroneus) muscle

Routine dissection has identified a previously unrecorded fibularis (peroneus) muscle in a 74-year-old male cadaver. The anomalous fibularis muscle was found lying immediately antero-medial to the fibularis longus (FL) muscle of the left leg. The anomalous muscle arose from the muscle belly of the FL in the proximal 1/2 of the leg. The muscle belly gave way to a long slender tendon that continued distally behind the lateral malleolus and inserted onto the superficial aspect of the inferior fibular retinaculum. The current finding and clinical significance are discussed.