Anatomic variants associated with peroneal tendon disorders: MR imaging findings in volunteers with asymptomatic ankles

PURPOSE: To evaluate prospectively, on magnetic resonance (MR) images in volunteers with asymptomatic ankles, various features of anatomic variants that are potentially associated with peroneal tendon disorders. MATERIALS AND METHODS: The study had institutional review board approval; informed consent was obtained from each volunteer. The prevalence of accessory peroneus quartus muscles, the location of the muscle-tendon junction of the peroneus brevis muscle, the prevalence and size of the peroneal tubercle and the retrotrochlear eminence, and the shape of the retromalleolar fibular groove were evaluated on MR images in 65 volunteers with asymptomatic ankles (35 women, 30 men; age range, 23-70 years; median age, 45 years). MR images were analyzed by two radiologists in consensus. The relationship between anatomic features and age and sex was analyzed by using Spearman rank correlation and the Wilcoxon rank sum test. RESULTS: A peroneus quartus muscle was identified in 11 (17%) ankles. Ninety percent of the musculotendinous junctions of the peroneus brevis muscle were located in a range between 27 mm proximal to and 13 mm distal to the fibular tip (median, 0 mm). A peroneal tubercle was identified in 36 (55%) ankles. Ninety percent of all peroneal tubercles were 4.6 mm or smaller (median height, 2.9 mm). A retrotrochlear eminence was seen in all ankles (median, 3.0 mm; 90% were 4.6 mm or smaller). The retromalleolar groove was concave in 18 (28%), flat in 28 (43%), convex in 12 (18%), and irregular in seven (11%) volunteers. A significant difference (P = .04) for the height of the retrotrochlear eminence was found between men (median, 3.4 mm) and women (median, 2.5 mm). All other P values were greater than .05. CONCLUSION: Anatomic variants thought to predispose individuals to peroneal tendon disorders can be seen in volunteers with asymptomatic ankles.     

Dynamic sonographic evaluation of peroneal tendon subluxation

OBJECTIVE: Peroneal tendon subluxation is a major cause of posttraumatic lateral ankle pain. Because peroneal subluxation often occurs only when the foot is dorsiflexed and everted, findings on static imaging studies may appear to be normal. We therefore evaluated the effectiveness of sonography in revealing peroneal tendon subluxation in patients performing stress maneuvers. MATERIALS AND METHODS: From June 2001 to June 2003, 13 consecutive patients (10 females and three males; mean age, 30.4 years; age range, 16-66 years) in whom peroneal tendon subluxation was clinically suspected were scanned with a high-frequency linear array transducer by an experienced sonologist. The ankles in 10 asymptomatic volunteers were also scanned. Sequential axial and longitudinal sonograms of the peroneus longus and peroneus brevis tendons at rest were obtained and evaluated for tendinitis and tendon tears. Real-time axial sonograms were then obtained while the foot was dorsiflexed and everted. Of the 13 patients, 12 had sonographic findings of peroneal tendon subluxation and underwent surgical exploration. The sonographic and surgical reports of these 12 patients were compared. RESULTS: All 12 patients with sonographic findings of peroneal tendon subluxation were subsequently found to have subluxation at surgery. The positive predictive value of dynamic sonography for peroneal tendon subluxation was therefore 100%. Sonography revealed peroneus brevis tendon tears in five patients and a peroneus longus tear in one; all findings were confirmed at surgery, with no false-positive sonograms. Only four of the 20 asymptomatic ankles showed subluxation, and none had any other tendon abnormalities. CONCLUSION: Sonography is an effective technique for diagnosing peroneal tendon subluxation, as well as associated tears of the peroneal tendons.     

Peroneal tendon pathology: Pre- and post-operative high resolution US and MR imaging

Peroneal tendon pathology is an important cause of lateral ankle pain and instability. Typical peroneal tendon disorders include tendinitis, tenosynovitis, partial and full thickness tendon tears, peroneal retinacular injuries, and tendon subluxations and dislocations. Surgery is usually indicated when conservative treatment fails. Familiarity with the peroneal tendon surgeries and expected postoperative imaging findings is essential for accurate assessment and to avoid diagnostic pitfalls. Cross-sectional imaging, especially ultrasound and MRI provide accurate pre-operative and post-operative evaluation of the peroneal tendon pathology. In this review article, the normal anatomy, clinical presentation, imaging features, pitfalls and commonly performed surgical treatments for peroneal tendon abnormalities will be reviewed. The role of dynamic ultrasound and kinematic MRI for the evaluation of peroneal tendons will be discussed. Normal and abnormal postsurgical imaging appearances will be illustrated.     

MRI features of chronic injuries of the superior peroneal retinaculum

OBJECTIVE: The aims of this study were to assess, grade, and surgically correlate previously unreported MRI features of superior peroneal retinacular injuries in nine surgically proven cases and to record all soft-tissue and bony abnormalities associated with these injuries. CONCLUSION: MRI was found to be a useful tool for detecting and grading superior peroneal retinacular injuries and providing information, important for presurgical planning, regarding common concomitant soft-tissue and osseous abnormalities of the lateral collateral ligaments, peroneal tendons, and fibular groove. Superior peroneal retinacular injuries are frequently associated with MRI evidence of peroneal tendon dislocations and tears. Conversely, routine MRI studies may not depict dislocated peroneal tendon injuries, despite clinical history to that effect.     

Peroneal tendon abnormalities in subjects with an enlarged peroneal tubercle

Objective

To examine the association between inframalleolar peroneal tendon abnormalities and an enlarged peroneal tubercle.

Materials and methods

Two independent readers evaluated consecutive ankle MR imaging studies to classify inframalleolar peroneal tendon findings as normal, tenosynovitis, partial tear or complete tear. The size and morphology of the peroneal tubercle was also recorded. We performed statistical analyses for inter-observer agreement and to assess differences in peroneal tubercle size between groups with and without peroneal tendon abnormalities.

Results

The study group comprised 121 subjects (mean age, 45.5 years) of whom 28 % (34 out of 121) had lateral ankle symptoms. The peroneal tubercle was absent in 56 % of subjects (68 out of 121). In subjects with a peroneal tubercle (>0 mm), the mean size was 3.5 mm (37 % triangular and 7 % plateau-shaped). Male subjects had significantly larger mean peroneal tubercle size than female subjects (2.1?±?2.5 vs 1.2?±?1.9 mm, P?=?0.04). Overall, 26 % (32 out of 121) of subjects had some peroneal tendon abnormality: 17 % (20 out of 121) had tenosynovitis and 17 % (20 out of 121) had partial thickness tears. The peroneal tubercle size was significantly larger in subjects with peroneal tendon partial tears (P?=?0.036), tenosynovitis (P?<?0.001), and when both abnormalities were present (P?=?0.007). ROC statistic showed 73 % sensitivity and 74 % specificity for detection of partial tears for peroneal tubercle size ≥4.3 mm.

Conclusion

Our study shows a significantly larger peroneal tubercle in subjects with inframalleolar peroneal tendon abnormalities. A cut-off of 4.3 mm showed good sensitivity and specificity for the presence of partial tears of the peroneal tendon.     

Computed tomographic assessment of soft tissue abnormalities following calcaneal fractures.

Computed tomographic (CT) examinations of 50 acute calcaneal fractures were compared with a further series of 77 fractures in which the date of injury preceded the CT by 6 months or more. 42 (84%) of the fractures in the acute group and 55 (71%) in the chronic group were classified as intra-articular and they form the basis of this study. The alteration in the position of the peroneal tendons in the two groups was similar, with a 5% or less difference in each category. In the acute group the peroneal tendons were normally located in 40.4% of the cases, entrapped by bone in 11.9%, subluxed in 33.3% and dislocated in 14.2%. Structural abnormalities of the peroneal tendons and surrounding soft tissues were identified in 52.4% of the acute group and in 61.1% of the chronic group. The incidence of partial rupture of the peroneal tendons in the chronic group was approximately one third that in the acute group, but the low incidence of complete tendon rupture remained unchanged. The inference from these observations is that, in the majority of cases, partial peroneal tendon rupture is reversible, whereas complete rupture is not. Seven fractures were common to both series and from this limited group the identification of haemorrhage around the peroneal tendons in the acute phase was shown not to be related to the subsequent development of chronic stenosing tenosynovitis. Various abnormalities of the medial tendons of the hindfoot were identified in 17% of the acute group and in 18% of the chronic group. Following calcaneal fracture, CT in both the immediate post-fracture period and in the late phase can be used to detect and classify the soft tissue changes. The limitations of comparing the two groups in this study are discussed.     

Peroneal tendon injury associated with calcaneal fractures: CT findings

Injury to the peroneal tendons is one of the major long-term complications of intraarticular calcaneal fractures and heretofore has been difficult to diagnose by noninvasive radiography. Retrospective review of CT scans of 24 intraarticular calcaneal fractures, obtained shortly after injury, identified 22 cases (92%) of acute peroneal tendon abnormalities. In most of these cases, multiple findings were present. These included lateral displacement in 14 (58%) of 24, impingement by bony fragments in eight (33%), subluxation or dislocation in six (25%), soft-tissue masses around the tendons representing hematomas or early scar tissue in five (21%), and entrapment of the tendons in three (13%). In 10 cases with long-term follow-up, impingement on the tendons by bony fragments correlated well with the subsequent development of peroneal tenosynovitis, while hematoma around the tendons or lateral displacement of the tendons was clinically insignificant. Thus, CT in the immediate postfracture period, can be used to detect and categorize acute peroneal tendon injuries as well as possibly to predict the likelihood and nature of subsequent development of peroneal tenosynovitis.     

Computed tomographic assessment of old calcaneal fractures

Prolonged pain and disability are common complications of calcaneal fractures. A prospective study was conducted on the value of computed tomography (CT) in 63 patients with 73 calcaneal fractures sustained more than 6 months before. The fractures were classified from the initial plain radiographs, and the patients' current clinical condition assessed in terms of a "disability score". The mean disability scores (MDS) associated with the different types of fracture were correlated with the CT findings. The highest MDS was found in the intra-articular fracture group which comprised 71% of the series. In this group the MDS was increased in the presence of post-traumatic osteoarthrosis of the subtalar joint (61% of cases), involvement of the calcaneocuboid joint (39% of cases) and subluxation/dislocation of the peroneal tendons (47% of cases). Structural abnormalities of the peroneal tendons were associated with a higher MDS including chronic tenosynovitis (eight cases), chronic partial tendon rupture (eight cases), complete peroneus brevis tendon rupture (two cases) and scarring indicating stenosing tenosynovitis (14 cases). A similar spectrum of appearances affecting the medial tendons of the hindfoot was identified in eight cases. Direct CT measurements of the degree of comminution did not correlate well with the patients' MDS. In the patient with persistent symptoms, CT is of value in the later assessment of long-term complications by revealing abnormalities of the subtalar joints and adjacent tendons.     

Soft-tissue radiography, computed tomography, and ultrasonography of partial Achilles tendon ruptures

Ultrasonography (US) was compared with soft-tissue radiography (STR) and computed tomography (CT) for demonstration of partial Achilles tendon ruptures. Thirty-nine patients suffering from chronic localized painful Achilles tendon swelling were examined. The patients had all undergone a previous clinical examination, resulting in a suspicion of a non-healed partial tear in 62 out of the 78 tendons. STR showed unspecific tendon pathology such as thickening and diffuse tendon margins. CT resulted in a better delineation of intra- as well as extratendinous abnormalities compared to STR. Various pathologic changes were seen on CT in 54 tendons and in 29 of these, localized intratendinous hypodensities indicated partial ruptures. At US, abnormal changes were observed in 69 tendons, of which 54 had discontinuity of tendon fibers, focal hypoechoic areas, and localized swelling indicating partial ruptures. In 9 cases with surgically proven partial ruptures, US was correct in all cases, while CT was false-negative in 3. STR only showed localized swelling. It was concluded that US was a better method than STR and CT for the detection of partial ruptures and the US findings correlated well with the surgical findings.     

Correlation of morphologic and pathologic features of the various tendon groups around the ankle: MR imaging investigation

Objective

To determine if a statistical association exists between abnormalities in one ankle tendon group (i.e., peroneal, medial flexor, or Achilles) and those in another.

Materials and methods

A retrospective analysis of 1.5-T and 3-T MR ankle examinations in 100 patients conducted between November 1, 2011 and April 1, 2012 was performed. The cross-sectional areas and diameters of the ankle tendons—Achilles (ACH), peroneus brevis (PB) and longus (PL), tibialis posterior (TP), flexor digitorum longus (FDL), and flexor hallux longus (FHL)—were measured, and the results were correlated to determine any association with the presence of qualitative abnormalities (tenosynovitis, tendinosis, and tendon tearing).

Results

Subjects with larger diameters of the ACH tendon also revealed larger PL, TP, FDL, and FHL tendon diameters and sectional areas. Furthermore, subjects with larger PL tendons generally revealed larger flexor tendons and the same was also true when medial compartment tendons were individually assessed and measurements compared among the three of them. There was a statistically significant association with regard to the presence of tendon abnormalities (tendinosis, tenosynovitis, and tearing) in both the peroneal and medial flexor tendons. The presence of an abnormality in the ACH tendon correlated strongly with increasing diameters and areas of all the other ankle tendons except for the PB tendon.

Conclusions

There is an association between quantitative and qualitative abnormalities of one group of tendons when compared with the others with respect to the ACH, medial flexor, and peroneal tendons of the ankle, which is perhaps explained by a retinacular and fascial complex that anatomically connects the three groups.     

Peroneal tendons: Use of kinematic MR imaging of the ankle to determine subluxation

The purpose of this study was to develop a technique for kinematic MRI of the ankle to evaluate subluxation of the peroneal tendons. A special device was used to perform incremental, passive positioning of the ankle from dorsiflexed to plantarflexed positions for the kinematic MRI examination. A fast spoiled gradient-recalled acquisition in the steady state pulse sequence was used to obtain axial images to assess the peroneal tendons during different positions of the ankle. Seven asymptomatic volunteers and five patients with suspected peroneal tendon subluxation were studied. There was no transverse displacement of the peroneal tendons observed in the asymptomatic subjects nor in two of the patients. Two patients had peroneal tendon subluxation observed on the kinematic MRI studies, and one patient had the peroneal tendons maintained in a displaced position in all ankle positions. The preliminary results suggest that kinematic MRI of the ankle is a potentially useful technique to facilitate evaluation of patients with suspected subluxation of the peroneal tendons, particularly in instances in which subluxation is position-dependent, and spontaneous reduction of the tendons may occur.     

Normal anatomy and pathologic conditions of ankle tendons: current imaging techniques.

Radiologic assessment of tendon injuries requires familiarity with normal anatomy and the capabilities of available imaging modalities. Tenography, less commonly used nowadays, does not allow direct visualization of tendons, so that partial ruptures and longitudinal splits may go undetected. Ultrasonography can depict tenosynovitis, tendinitis, and complete tendon rupture of the Achilles tendon, but the other tendons are difficult to visualize with this technique. Magnetic resonance (MR) imaging is superior to computed tomography (CT) in the depiction of tenosynovitis and peritendinitis, tendinitis, tendon rupture, and tendon dislocation and subluxation. CT can demonstrate these abnormalities, but accompanying scar tissue or edema, early changes of tendon degeneration, and small amounts of inflammatory fluid are difficult to differentiate with this technique. CT is superior for demonstrating calcifications, convex retromalleolar groove, bone fragments, or spurs that complicate tendon dislocation and rupture. Although the authors prefer MR imaging, they caution that all of the modalities are not always specific and that differentiation between closely related processes such as tendinitis and early tendon rupture is difficult.     

Operative treatment of peroneusbrevis and peroneus longus tendon tears

The peroneal tendons provide important functions to the foot and ankle including stabilization of the lateral ankle and plantar flexion of the first ray. Injury to the peroneal tendons might occur as a result of an ankle or peroneal tendon instability or a local degenerative process. Conservative management for peroneal tendon tears is not uniformly successful and surgical management remains a common method for treatment. The peroneal tendon rupture might be treated by simple repair of isolated longitudinal rupture, by excision of degenerative tendon and longitudinal repair of the remaining tendon, or by excision of degenerative tendon and side-to-side tenodesis for extensive tendon damage. Stability of the tendons also is addressed by bony and or soft tissue stabilization procedures.     

Surgical treatment of concomitant chronic ankle instability and longitudinal rupture of the peroneus brevis tendon

Chronic lateral ankle instability can be associated with a longitudinal rupture of the peroneus brevis tendon. Patients with these problems have atypical posterolateral or retromalleolar pain, as well as clinical signs of ligamentous instability. This injury is frequently concomitant with lateral ligament injuries and the injury mechanism is similar; however, the tendon rupture is often missed. Laxity or insufficiency of the superior peroneal retinaculum allows the anterior part of the peroneus brevis tendon to ride upon the sharp posterior fibular edge, resulting in a longitudinal rupture of the tendon. We report on the results after surgical treatment in nine patients (10 ankles) with combined instability of the lateral ankle ligaments and longitudinal rupture of the peroneus brevis tendon. All these patients underwent surgical repair of the peroneus tendon, reconstruction of the superior peroneal retinaculum, removal of the sharp posterior edge of the fibula and correction of the ligamentous instability of the anterior talofibular and calcaneofibular ligaments. One constant finding at surgery was a longitudinal intratendineal rupture of the peroneus brevis tendon combined with insufficiency of the superior peroneal retinaculum and insufficiency of the lateral ligaments. At follow-up 3 (2–5) years postoperatively, the functional results were excellent or good in nine ankles and fair in one. All the patients with excellent or good results had resumed their preinjury activity level. We conclude that this lesion should be suspected in patients with lateral ligamentous instability, combined with retromalleolar pain. In these cases, it is important to address both the tendon rupture and the ligamentous insufficiency.     

Initial experience with visualizing hand and foot tendons by dual-energy computed tomography

PurposeTo assess the feasibility of visualizing hand and foot tendons by dual-energy computed tomography (CT).Methods and materialsTwenty patients who suffered from hand or feet pains were scanned on dual-source CT (Definition, Forchheim, Germany) with dual-energy mode at tube voltages of 140 and 80 kV and a corresponding ratio of 1:4 between tube currents. The reconstructed images were postprocessed by volume rendering techniques (VRT) and multiplanar reconstruction (MPR). All of the suspected lesions were confirmed by surgery or follow-up studies.ResultsTwelve patients (total of 24 hands and feet, respectively) were found to be normal and the other eight patients (total of nine hands and feet, respectively) were found abnormal. Dual-energy techniques are very useful in visualizing tendons of the hands and feet, such as flexor pollicis longus tendon, flexor digitorum superficialis/profundus tendon, Achilles tendon, extensor hallucis longus tendon, and extensor digitorum longus tendon, etc. It can depict the whole shape of the tendons and their fixation points clearly. Peroneus longus tendon in the sole of the foot was not displayed very well. The distal ends of metacarpophalangeal joints with extensor digitoium tendon and extensor pollicis longus tendon were poorly shown. The lesions of tendons such as the circuitry, thickening, and adherence were also shown clearly.ConclusionDual-energy CT offers a new method to visualize tendons of the hand and foot. It could clearly display both anatomical structures and pathologic changes of hand and foot tendons.     

Magnetic resonance imaging findings in patients with peroneal tendinopathy and peroneal tenosynovitis

Objective To compare the magnetic resonance (MR) imaging findings of a group of patients with clinically diagnosed peroneal tendonopathy and peroneal tenosynovitis with the MR imaging findings of a control group of patients with no clinical evidence of peroneal tendon disorder. Subjects and methods The MR examinations of 24 patients with symptomatic peroneal tendinopathy or peroneal tenosynovitis and 70 patients with no clinical evidence of peroneal tendon disorder were retrospectively reviewed to determine the presence or absence of four MR imaging findings: 1) predominantly or uniform intermediate signal intensity within the peroneal tendons on one or more axial proton density-weighted images, 2) predominantly or uniform intermediate signal intensity within the peroneal tendons on three consecutive axial proton density-weighted images, 3) intermediate T2 signal intensity within the peroneal tendons, and 4) circumferential fluid within the common peroneal tendon sheath greater than 3 mm in maximal width. The sensitivity and specificity of these MR imaging findings for determining the presence or absence or symptomatic peroneal tendinopathy or peroneal tenosynovitis were calculated. Results The sensitivity of MR imaging findings 1, 2, 3, and 4 for determining the presence of peroneal tendinopathy or peroneal tenosynovitis were 92%, 92%, 50%, and 17% respectively. The specificity of MR imaging findings 1, 2, 3, and 4 for determining the absence of peroneal tendinopathy or peroneal tenosynovitis were 57%, 79%, 93%, and 100% respectively. Conclusion The presence of predominantly or uniform intermediate signal intensity within the peroneal tendons on three consecutive axial proton density-weighted images is a highly sensitive and moderately specific indicator of symptomatic peroneal tendinopathy. The presence of intermediate T2 signal within the peroneal tendons, and the presence of circumferential fluid within the peroneal tendon sheath greater than 3 mm in maximal width, are highly specific indicators of peroneal tendinopathy and peroneal tenosynovitis respectively.     

Asymptomatic Achilles,patellar, and quadriceps tendinopathy: A longitudinal clinical and ultrasonographic study in elite fencers

Lower limb tendon changes detected at imaging are common among asymptomatic athletes. We aimed to prospectively assess the clinical status, tendon structure, and vascularity of lower limb tendons of elite fencers, and predict the risk of developing symptoms over time. Clinical examination, changes at ultrasonography (US), and Power Doppler (PD) flow of both the Achilles, patellar, and quadriceps tendon were assessed in 37 elite fencers in January 2007 and 3 years after. Two hundred and twenty‐two tendons were examined. At the last appointment, patellar tendons diagnosed as abnormal at baseline were more likely to develop symptoms than those normal at baseline (P < 0.05, Fisher's exact test), while US and PD abnormalities on Achilles and quadriceps tendons were no predictive for development of symptoms over years. A very low percentage of tendons diagnosed as normal at baseline (1.45%) showed US abnormalities at 3‐year follow‐up. In asymptomatic elite fencers, structural changes are relatively common at US and PD assessment of Achilles, quadriceps, and patellar tendons. It seems unlikely that additional PD investigations provide further information or change prognosis in patients with US diagnosis of tendinopathy.     

MDCT of tendon abnormalities using volume-rendered images

OBJECTIVE: Our objectives were to report tendon abnormalities diagnosed on 3D volume-rendered images from MDCT data and to validate the clinical usefulness of this technique. CONCLUSION: We present 18 tendon abnormalities from 16 patients that were diagnosed on 3D volume-rendered MDCT images generated by commercially available software. Certain abnormalities such as avulsions, partial tears, and dislocations of tendons are clearly shown by this technique. This technique may prove useful in the evaluation of tendon abnormalities when MRI or sonography cannot be used.     

Significance of ultrasonographically detected asymptomatic tendinosis in the patellar and achilles tendons of elite soccer players: a longitudinal study

BACKGROUND: Chronic tendinosis of the Achilles or patellar tendons, or both, is one of the most frequent and severe conditions that affects athletes in sports such as soccer. It can often end an athlete's sports activity. HYPOTHESIS: Ultrasonography of asymptomatic tendons can be used to predict which athletes will develop tendon symptoms. STUDY DESIGN: Longitudinal study. METHODS: Using ultrasonography of the ankle and knee, we examined 54 elite soccer players in the top Danish soccer league before and after a single season (in January and December). RESULTS: At the start of the season, ultrasonography had revealed abnormalities in 29% of those examined. Eighteen percent (18 of 98 tendons) were observed to have abnormal sonographic findings in the patellar tendon at the initial examination in January. These athletes were found to have a 17% risk of developing symptomatic jumper's knee during the 12-month season. Eleven percent (11 of 96 tendons) were observed to have abnormal sonographic findings in the Achilles tendon at the initial examination; it was calculated that they had a 45% risk of developing symptoms of Achilles tendinosis. Only one of the players with normal tendons in January actually developed symptoms by the end of the season. CONCLUSIONS: For the first time it is now possible to identify risk factors for the development of serious tendon disorders in asymptomatic athletes. Future studies may be directed at developing preventive treatment to reduce the risk of chronic, therapy-resistant symptoms of tendinosis and ruptures.     

The ultrasonographic characterization of tendons

Ultrasonography has not been utilized in the diagnosis of musculoskeletal disorders. However, the superficial location of tendons and ligaments lend themselves to evaluation by this modality. The ultrasonographic characteristics of the normal Achilles tendon are described in both the rabbit and man. The characteristic ultrasonographic findings after injury to the Achilles tendon are also determined. This imaging technique provides a sharp definition of the tendon and surrounding structures and easily demonstrates abnormalities. The superficially located quadriceps tendon is also well visualized by ultrasound and representative examples are shown. Ultrasound should be considered as another useful method for evaluation of these superficial musculoskeletal structures.