Differential Plantaris-Achilles Tendon Motion: A Sonographic and Cadaveric Investigation

Musculoskeletal disorders in padel: from biomechanics to sonography

Padel is a racket sport, combining high-frequency and low-intensity athletic gestures, that has been gaining growing scientific interest in recent years. Musculoskeletal injuries are very common among padel players with an incidence rate of 3 per 1000 h of training and 8 per 1000 matches. To the best of our knowledge, a comprehensive collection describing the most common sonographic findings in padel players with musculoskeletal injuries is lacking in the pertinent literature. In this sense, starting from the biomechanical features of padel-specific gestures we have reported the ultrasonographic patterns of most frequent injuries involving the upper limb, the trunk, and the lower limb. Indeed, comprehensive knowledge of the biomechanical and clinical features of musculoskeletal injuries in padel is paramount to accurately perform a detailed ultrasound examination of the affected anatomical site. So, the present investigation aims to provide a practical guide, simple and ready-to-use in daily practice, to optimize the sonographic assessment of padel players by combining it with the clinical findings and the biomechanical features of athletic gestures.

Tendinopathic Plantaris but Normal Achilles Tendon Found in About One-Fifth of Patients Not Responding to Conservative Achilles Tendon Management - Results from a Prospective WALANT Surgical Case Series on 105 Tendons

Purpose

Midportion Achilles tendinopathy is a relatively common condition. This study aimed to investigate the presence of a normal Achilles tendon, but a tendinopathic plantaris tendon, in a large and consecutive prospective sample of patients referred to a specialised tendon clinic for midportion Achilles tendon pain not responding to non-surgical treatment.

Patients and Methods

A total of 105 consecutive tendons were operated on in 81 patients (62 males) suffering from painful midportion Achilles tendon pain. Clinical examination, ultrasound (US) and colour Doppler (CD) examination, and wide awake local anaesthetic no tourniquet (WALANT) surgery were performed in all patients.

Results

For 19/105 (18%) tendons from 14 patients, clinical examination suspected plantaris tendinopathy alone as there was a distinct tenderness on the medial side, but no thickening of the Achilles tendon. US examination followed by surgery confirmed the diagnosis.

Conclusion

Midportion Achilles tendon pain is not always related to Achilles tendinopathy since pain related to the plantaris tendon alone was found in almost every fifth patient. Consequently, there is an obvious need for proper examination to identify the pain source and establish a correct diagnosis before treatment.

Combined Midportion Achilles and Plantaris Tendinopathy: A 1-Year Follow-Up Study after Ultrasound and Color-Doppler-Guided WALANT Surgery in a Private Setting in Southern Sweden

Background and Objectives: Chronic painful midportion Achilles combined with plantaris tendinopathy can be a troublesome condition to treat. The objective was to prospectively follow patients subjected to ultrasound (US)- and color doppler (CD)-guided wide awake, local anesthetic, no-tourniquet (WALANT) surgery in a private setting. Material and Methods: Twenty-six Swedish patients (17 men and 9 women, mean age 50 years (range 29–62)) and eight international male patients (mean age of 38 years (range 25–71)) with combined midportion Achilles and plantaris tendinopathy in 45 tendons altogether were included. All patients had had >6 months of pain and had tried non-surgical treatment with eccentric training, without effect. US + CD-guided surgical scraping of the ventral Achilles tendon and plantaris removal under local anesthesia was performed on all patients. A 4–6-week rehabilitation protocol with an immediate full-weight-bearing tendon loading regime was used. The VISA-A score and a study-specific questionnaire evaluating physical activity level and subjective satisfaction with the treatment were used for evaluation. Results: At the 1-year follow-up, 32/34 patients (43 tendons) were satisfied with the treatment result and had returned to their pre-injury Achilles tendon loading activity. There were two dropouts (two tendons). For the Swedish patients, the mean VISA-A score increased from 34 (0–64) before surgery to 93 (61–100) after surgery (p < 0.001). There were two complications, one wound rupture and one superficial skin infection. Conclusions: For patients suffering from painful midportion Achilles tendinopathy and plantaris tendinopathy, US + CD-guided surgical Achilles tendon scraping and plantaris tendon removal showed a high satisfaction rate and good functional results 1 year after surgery.

Anatomical Classification for Plantaris Tendon Insertion and Its Clinical Implications: A Cadaveric Study

The purposes of this study were to ascertain the morphological characteristics of a plantaris tendon (PT) insertion using a larger-scale dissection of Korean cadavers and to classify the types of PT insertion related to the calcaneal tendon (CT). A total of 108 feet from adult formalin-fixed cadavers (34 males, 20 females) were dissected. The morphological characteristics and measurements of the PT insertion were evaluated. Five types of PT insertion were classified, wherein the most common type was Type 1 (39 feet, 63.1%). Type 2 and Type 3 were similar, with 16 feet (14.8%) and 15 feet (13.9%), respectively. Type 4 (6 feet, 5.6%) was the rarest type, and Type 5 had 25 feet (23.1%). The case of an absent PT was noted in 7 feet (6.5%). In the proximal portion, the tendon had a thick and narrow shape, became thin and wide in the middle portion, and then changed to thick and narrow again just before the insertion into the calcaneal tuberosity. This study confirmed the five types according to the location of the PT and the area of its insertion-related CT. The morphology of the PT insertion may be anatomically likely to influence the occurrence of tendinopathy in the CT.

Sharp pain in a normal Achilles tendon of a professional female football player was related to a plantaris tendon in a rare position: a case report

BACKGROUND

Plantaris tendinopathy and plantaris-associated Achilles tendinopathy can be responsible for chronic pain in the Achilles tendon midportion, often accompanied by medial tenderness. As conservative treatments are less successful for this patient group, proper diagnosis is important for decision making. This report presents a case with plantaris tendinopathy in a rare (superficial) location.

CASE PRESENTATION

This article describes a pain history and treatment timeline of a professional Swedish female soccer player (32 years old, Northern European ethnicity, white) who suffered from sharp pain in the Achilles tendon midportion and tenderness on the medial and superficial side for about 2 years. Conservative treatments, including eccentric exercises, were not successful and, to some extent, even caused additional irritation in that region. Ultrasound showed a wide and thick plantaris tendon located on the superficial side of the Achilles tendon midportion. The patient was surgically treated with local removal of the plantaris tendon. After surgery there was a relatively quick (4-6 weeks) rehabilitation, with immediate weight bearing, gradual increased loading, and return to running activities after 4 weeks. At follow-up at 8 weeks, the patient was running and had not experienced any further episodes of sharp pain during change of direction or sprinting.

CONCLUSIONS

The plantaris tendon should be considered as a possible source of Achilles tendon pain. This case study demonstrates that the plantaris tendon can be found in unexpected (superficial) positions and needs to be carefully visualized during clinical and imaging examinations.

Achilles Scraping and Plantaris Tendon Removal Improves Pain and Tendon Structure in Patients with Mid-Portion Achilles Tendinopathy-A 24 Month Follow-Up Case Series

Background: Studies have demonstrated that a sub-group of patients with medial Achilles pain exhibit Achilles tendinopathy with plantaris tendon involvement. This clinical condition is characterised by structural relationships and functional interference between the two tendons, resulting in compressive or shearing forces. Surgical plantaris tendon removal together with an Achilles scraping procedure has demonstrated positive short-term clinical results. The aim of this case series was to determine the long-term outcomes on pain and Achilles tendon structure. Methods: 18 consecutive patients (13 males; 5 females; mean age 39 years; mean symptom duration 28 months), of which three were elites, were included. Clinical examination, b-mode ultrasound (US) and Ultrasound Tissue Characterisation (UTC) confirmed medial Achilles tendon pain and tenderness, medial Achilles tendinopathy plus a plantaris tendon located close to the medial side of the Achilles tendon. Patients underwent US-guided local Achilles scraping and plantaris tendon removal followed by a structured rehabilitation program. Outcomes were VISA-A score for pain and function and UTC for Achilles structure. Results: 16 of 18 patients completed the 24 months follow-up. Mean VISA-A scores increased from 58.2 (±15.9) to 92.0 (±9.2) (mean difference = 33.8, 95% CI 25.2, 42.8, p < 0.01). There was an improvement in Achilles structure with mean organised echo pixels (UTC type I+II, in %) increasing from 79.9 (±11.5) to 86.4 (±10.0) (mean difference = 6.5%, 95% CI 0.80, 13.80, p =0.01), exceeding the 3.4% minimum detectable change. All 16 patients reported satisfaction with the procedure and 14 returned to pre-injury activity levels. There were no reported complications. Conclusions: Improved pain, function and tendon structure were observed 24 months after treatment with Achilles scraping and plantaris excision. The improvement in structure on the medial side of the Achilles after plantaris removal indicates that compression from the plantaris tendon might be an important presenting factor in this sub-group.

Snapping Plantaris Tendon: A Rare Case in a Competitive Dancer

Pathology associated with the plantaris includes rupture of the tendon and an association with mid-substance Achilles tendinopathy in some patients. There have only been two previous case reports in the literature in English language describing snapping of the plantaris tendon. We present a case report of a 15-year-old female competitive dancer who described pain and an audible popping at the medial margin of the Achilles tendon while squatting. Physical examination revealed visible and audible popping of the plantaris, and ultrasonography confirmed the diagnosis. After symptoms persisted despite nonsurgical treatment with physical therapy, the patient underwent an open plantaris tenotomy. By 8 weeks after surgery, she had resumed dancing. Twenty-three months after her operation, she reported an excellent outcome and full recovery with no limitations to her physical activity. She reported having no pain, a Foot and Ankle Ability Measure Activities of Daily Living Subscale score of 100, and a Foot and Ankle Ability Measure Sports Subscale score of 100. This case demonstrates a successful course of treatment for this uncommon pathology within the context of a competitive dancer.

Ultrasound and surgical inspection of plantaris tendon involvement in chronic painful insertional Achilles tendinopathy: a case series

Objectives

Chronic painful insertional Achilles tendinopathy is known to be difficult to manage. The diagnosis is not always easy because multiple different tissues can be involved. The plantaris tendon has recently been described to frequently be involved in chronic painful mid-portion Achilles tendinopathy. This study aimed to evaluate possible plantaris tendon involvement in patients with chronic painful insertional Achilles tendinopathy.

Methods

Ninety-nine consecutive patients (74 males, 25 females) with a mean age of 40 years (range 24–64) who were surgically treated for insertional Achilles tendinopathy, were included. Clinical examination, ultrasound (US)+Doppler examination, and surgical findings were used to evaluate plantaris tendon involvement.

Results

In 48/99 patients, there were clinical symptoms of plantaris tendon involvement with pain and tenderness located medially at the Achilles tendon insertion. In all these cases, surgical findings showed a thick and wide plantaris tendon together with a richly vascularised fatty infiltration between the plantaris and Achilles tendon. US examination suspected plantaris involvement in 32/48 patients.

Conclusion

Plantaris tendon involvement can potentially be part of the pathology in chronic painful insertional Achilles tendinopathy and should be considered for diagnosis and treatment when there is distinct and focal medial pain and tenderness.

Level of evidence

IV case series.

Proposal for a new classification of plantaris muscle origin and its potential effect on the knee joint

PURPOSE

The plantaris muscle (PM) is typically characterized by a short, slim and spindle-shaped muscle belly and long, thin tendon. It is situated posterior to the popliteal muscle, and anterior to the lateral head of the gastrocnemius muscle (GM). Little information exists regarding the high variability of origin of the PM. The main aim of the study was hence to characterize the morphology of the PM and its place of origin, classify it and evaluate its prevalence.

METHODS

Classical anatomical dissection was performed on 142 lower limbs (77 left, and 65 right) fixed in 10% formalin solution. The morphology of the origin of the PM and its prevalence was evaluated.

RESULTS

The PM was present in 128 lower limbs (90.1%). Six types of origin were observed, the most common being Type I (48.4%). This type was divided into two subtypes (A-B): subtype A attaching to the lateral head of the GM, lateral femoral condyle and to the capsule of the knee joint, and subtype B, attaching to the lateral head of the GM, the lateral femoral condyle, knee joint capsule and the popliteal surface of the femur. The second most common type was Type II (25%), attaching to the capsule of the knee joint and, indirectly, to the lateral head of the GM through the lateral femoral condyle. The third most common type was Type III (10.15%), attaching to the lateral femoral condyle and the knee joint capsule. Type IV (6.25%), the rarest type, attached to the lateral femoral condyle, knee joint capsule and to the iliotibial band. Type V (8.6%) originated only from the lateral condyle of the femur. Type VI (1.6%) contains only "rare cases".

CONCLUSION

The PM presents high morphological variability, and its status as a residual muscle should be reconsidered. Our presented classification of its types of origin is a valuable addition for both clinicians and anatomists. Level of Evidence - II Basic Science Research.

It is possible to release the plantaris tendon under ultrasound guidance: a technical description of ultrasound guided plantaris tendon release (UPTR) in the treatment of non-insertional Achilles tendinopathy

PURPOSE

Open plantaris tendon excision and ventral paratendinous stripping is a recognised treatment option in selected patients with non-insertional Achilles tendinopathy. The aim of this study was to develop a minimally invasive outpatient technique of ultrasound guided plantaris tendon release (UPTR).

METHODS

A 19 gauge needle, 15 gauge scalpel blade, hook knife (Smith and Nephew, Boston, MA, USA) and a beaver blade (Arthrex, Naples, FL, USA), were used under ultrasound guidance to identify and divide the plantaris tendon in 12 cadaveric legs. Specimens were dissected to identify whether division of the plantaris tendon had been successful. UPTR was subsequently performed on patients.

RESULTS

The 15 gauge scalpel blade, hook knife (Smith and Nephew, Boston, MA, USA) and beaver blade (Arthrex, Naples, FL, USA) were all able to cut the plantaris tendon. However, on dissection the hook knife (Smith and Nephew, Boston MA) caused less damage to surrounding structures. Subsequently, the plantaris tendon was successfully divided in three patients using UPTR technique without complication.

CONCLUSION

UPTR is a viable technique for treating plantaris related non-insertional Achilles tendinopathy.

Prevalence of Coexistent Plantaris Tendon Pathology in Patients with Mid-Portion Achilles Pathology: A Retrospective MRI Study

Co-existence of Plantaris tendinopathy (PT) in patients with mid-Achilles tendinopathy (Mid-AT) is of clinical significance. This study aims to describe the MRI-based pathological characteristics of co-existing PT and Mid-AT. One-hundred MRI studies of patients diagnosed with Mid-AT were retrospectively analysed by an experienced musculoskeletal radiologist. Presence or absence of a Plantaris tendon, co-existing PT with Mid-AT, insertional characteristics of Plantaris tendon, and maximum anteroposterior thickness of the tendon in Mid-AT (axial images) were evaluated. When PT co-existed with Mid-AT, the location of the tendon pathologies in relation to calcaneal insertion was assessed (sagittal images) and their association was analysed using the coefficient of variation (CV) and Pearson’s correlation coefficient. Plantaris was present in 84 cases (84%), and Mid-AT and PT co-existed in 10 cases (10%). A greater variability in the location of Plantaris pathology (CV = 42%) than Achilles tendinopathy (CV = 42%) was observed. The correlation coefficient also revealed a low and non-significant association between the location of two pathologies when they exist together (r = +0.06; p = 0.88). Clinical evaluation of Achilles tendon pain needs careful consideration into the possible co-existence of Plantaris pathology. The considerable difference observed in the location of PT and Mid-AT suggest possible isolated pathologies and differentials for Achilles tendon pain.

Sonographically Guided Plantaris Tendon Release: A Cadaveric Validation Study

BACKGROUND

The plantaris tendon (PT) has been implicated in the pathogenesis of symptoms in a subset of patients with Achilles region pain syndromes and traditionally has been managed via open surgical resection. Although the PT can be visualized on ultrasound, a minimally invasive technique for sonographically guided PT release has not been formally described.

OBJECTIVE

To validate a technique to perform sonographically guided PT release in an unembalmed cadaveric model.

DESIGN

Prospective, cadaveric laboratory investigation.

SETTING

Procedural skills laboratory in a tertiary medical center.

SUBJECTS

Twenty unembalmed cadaveric knee-ankle-foot specimens (10 right, 10 left) obtained from 16 donors (6 male, 10 female) ages 55-96 years (mean 82.6 years) with body mass indexes of 14.1-33.2 kg/m² (mean 23.3 kg/m² ).

METHODS

After simulated local anesthesia and sonographically guided hydrodissection of the plantaris tendon-Achilles tendon interval, a single experienced operator performed sonographically guided PT release on each specimen using an in-plane, lateral-to-medial approach, a commercially available, disposable 3.0-mm hook knife, and either a 17-5 MHz or 15-7 MHz linear array transducer. Each specimen was subsequently dissected to assess for PT release and iatrogenic injury.

MAIN OUTCOME

Status of the PT, Achilles tendon, and regional neurovascular structures as determined by dissection.

RESULTS

All 20 PT releases were completed in a single attempt through a 3- to 5-mm incision. Dissection confirmed complete PT release in all specimens without damage to the adjacent Achilles tendon or regional neurovascular structures.

CONCLUSION

Sonographically guided PT release is technically feasible and can be performed while avoiding injury to the Achilles tendon and regional neurovascular structures. Additional research is warranted to further define the role of sonographically guided PT release in patients with suspected PT-mediated Achilles region pain syndromes.

LEVEL OF EVIDENCE

IV.

Surgical plantaris tendon removal for patients with plantaris tendon-related pain only and a normal Achilles tendon: a case series

Objectives

Surgical removal of the plantaris tendon can cure plantaris-associated Achilles tendinopathy, a condition in which Achilles and plantaris tendinopathy coexist. However, rare cases with plantaris tendinopathy alone are often misdiagnosed due to a normal Achilles tendon.

Design and setting

Prospective case series study at one centre.

Participants

Ten consecutive patients (9 men and one woman, mean age 35 years, range 19–67) with plantaris tendon-related pain alone in altogether 13 tendons were included. All had had a long duration (median 10 months, range 3 months to 10 years) of pain symptoms on the medial side of the Achilles tendon mid-portion. Preoperative ultrasound showed thickened plantaris tendon but a normal Achilles tendon.

Interventions

Operative treatment consisting of ultrasound-guided excision of the plantaris tendon.

Primary and secondary outcome measures

Scores from Victorian Institute of Sports Assessment-Achilles questionnaire (VISA-A)were taken preoperatively and postoperatively (median duration 10 months). Patient satisfaction and time until full return to sports activity level was asked by a questionnaire.

Results

The VISA-A scores increased from 61 (range 45–81) preoperatively to 97 (range 94–100) postoperatively (p<0.01). Follow-up results at 10 months (range 7–72 months) on 9/10 patients showed full satisfaction and return to their preinjury sports or recreational activity

Conclusion

The plantaris tendon should be kept in mind when evaluating painful conditions in the Achilles tendon region, especially when no Achilles tendinopathy is present. Excision of the plantaris tendon via a minor surgical procedure in local anaesthesia results in a good outcome.

The Plantaris Muscle Tendon and Its Relationship with the Achilles Tendinopathy

Purpose

Although the plantaris muscle (PM) is vestigial in humans, it has a significant clinical role in procedures such as grafting. However, recent reports suggest its potential involvement in the tendinopathy of the midportion of the Achilles tendon. The aim of the study is therefore to evaluate morphological variation of the PM with regard to its potential conflict with the Achilles tendon.

Material and Methods

Classical anatomical dissection was performed on 130 lower limbs (71 right, 59 left) fixed in 10% formalin solution. The morphology of the PM was assessed regarding the relationship between the course of the plantaris tendon and the calcaneal tendon.

Results

The PM was present in 89.2% of cases. The findings indicate the presence of a new type of PM tendon insertion in which the tendon is inserted into the tarsal canal flexor retinaculum, potentially affecting the tendinopathy of the tibialis posterior muscle. In 26 cases (22.4%), insertion blended with the Achilles tendon (Type II), which may increase the risk of Achilles tendinopathy.

Conclusion

The anatomical variation of PM tendon morphology may create a potential conflict with the Achilles tendon and the tibialis posterior tendon, thus increasing the possibility of tendinopathy.

Differential Motion and Compression Between the Plantaris and Achilles Tendons: A Contributing Factor to Midportion Achilles Tendinopathy?

BACKGROUND

The plantaris tendon (PT) has been thought to contribute to symptoms in a proportion of patients with Achilles midportion tendinopathy, with symptoms improving after PT excision.

HYPOTHESIS

There is compression and differential movement between the PT and Achilles tendon (AT) during ankle plantarflexion and dorsiflexion.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Eighteen fresh-frozen cadaveric ankles (mean ± SD age: 35 ± 7 years, range = 27-48 years; men, n = 9) were mounted in a customized testing rig, where the tibia was fixed but the forefoot could be moved freely. A Steinmann pin was drilled through the calcaneus, enabling a valgus torque to be applied. The soleus, gastrocnemius, and plantaris muscles were loaded with 63 N with a weighted pulley system. The test area was 40 to 80 mm above the os calcis, corresponding to where the injury is observed clinically. Medially, the AT and PT were exposed, and a calibrated flexible pressure sensor was inserted between the tendons. Pressure readings were recorded with the ankle in full dorsiflexion, full plantarflexion, and plantargrade and repeated in these positions with a 5 N·m torque, simulating increased hindfoot valgus. The pressure sensor was removed and the PT and AT marked with ink at the same level, with the foot held in neutral rotation and plantargrade. Videos and photographs were taken to assess differential motion between the tendons. After testing, specimens were dissected to identify the PT insertion. One-way analysis of variance and paired t tests were performed to make comparisons.

RESULTS

The PT tendons with an insertion separate from the AT demonstrated greater differential motion through range (14 ± 4 mm) when compared with those directly adherent to the AT (2 ± 2 mm) ( P < .001). Mean pressure between the PT and AT rose in terminal plantarflexion for all specimens ( P < .001) and was more pronounced with hindfoot valgus ( P < .001).

CONCLUSION

The PT inserting directly into the calcaneus resulted in significantly greater differential motion as compared with the AT. Tendon compression was elevated in terminal plantarflexion, suggesting that adapting rehabilitation tendon-loading programs to avoid this position may be beneficial.

CLINICAL RELEVANCE

The insertion pattern of the PT may be a factor in plantaris-related midportion Achilles tendinopathy. Terminal range plantarflexion and hindfoot valgus both increased AT and PT compression, suggesting that these should be avoided in this patient population.

Anatomical variations of the palmaris longus muscle including its relation to the median nerve - a proposal for a new classification

BACKGROUND

The palmaris longus (PL) muscle is characterised by high morphological diversity, and its tendon crosses the median nerve (MN) at different levels. Due to the fact that the palmaris longus tendon is routinely harvested for reconstruction of other tendons, knowledge of its morphological variations is clinically important. Therefore, the purpose of the study was to suggest a new morphological classification of the PL muscle and characterise the relationship of its tendon to the median nerve.

METHODS

Standard dissection was performed on 80 randomised and isolated upper limbs (40 left and 40 right) fixed in a 10% formalin solution. Measurements of muscle belly and tendon were obtained. The course and location of tendon insertion, as well as its relationship to the median nerve, were noted.

RESULTS

The palmaris longus muscle was present in 92.5% of specimens. Three types of palmaris longus muscle were identified based on the morphology of its insertion (types I-III) and these were further subdivided into three subgroups (A-C) according to the ratio of the length of the muscle belly and its tendon. The most frequent was type I (78.8%), where the tendon attached to the palmar aponeurosis, and subtype B, where the tendon-to-belly ratio was 1-1.5 (41.1%). The mean distance from the interstyloid line to the crossing between the median nerve and the palmaris longus tendon was 31.6 mm. In addition, two types of palmaris longus were described.

CONCLUSION

The presented classification of palmaris longus muscle types allows a better characterization of its diversity and may be useful in planning tendon grafting.