Competence of the deltoid ligament in bimalleolar ankle fractures after medial malleolar fixation

Syndesmosis Stabilisation: Screws Versus Flexible Fixation

Orthopedic surgery is not short of situations where there is controversy regarding optimum management. Treating ankle syndesmosis injuries is an example where practice varies widely and there are many questions that remain unsatisfactorily answered. When addressing the type of syndesmosis stabilization that is required it is essential to ascertain the extent of instability. Only then can a logical approach to restoring the ankle mortise be achieved. Fixation of fibula shaft fractures and posterior malleolus fractures can restore sufficient stability to render syndesmosis stabilization unnecessary. The indications and techniques for stabilizing the distal tibiofibular joint are reviewed with clinical examples.

Medial Malleolar Fractures and Associated Deltoid Ligament Disruptions: Current Management Controversies

Operative fixation of medial malleolar fractures, whether isolated or in the setting of bi- or trimalleolar fractures, remains controversial. Increasingly, anatomic reduction and internal fixation is used to treat medial malleolar fractures to avoid long-term sequelae of symptomatic nonunion and posttraumatic osteoarthritis. However, outcomes have not been significantly different between operative and nonoperative cohorts. Repair of associated deltoid ligament disruption is not common because of reportedly poor outcomes. This review provides an overview of the literature on medial malleolar fracture fixation and current treatment options. [Orthopedics. 2017; 40(2):e216-e222.].

The Morphology and Prevalence of the Deltoid Complex Ligament of the Ankle

The deltoid ligament is a complex structure of the tibiotalar joint that limits the translation and tilting of the talus. It is often associated with injuries of the ankle joint. The deltoid complex ligament has 2 layers; one superficial with 4 bands and the other deep with 2 bands. Nevertheless, the prevalence and size of its components are reported with some variability in the literature. The aim of this meta-analysis is to generate weighted values of the prevalence, size, and attachment surface areas of its components. Eight studies met the inclusion criteria with a total of 142 ankle specimens. The analyses demonstrate that the most consistent component is the deep posterior tibiotalar (100%), followed by the tibiospring (≈94%), the tibionavicular (≈90%), and the tibiocalcaneal (85%). The superficial posterior ligament and the deep anterior tibiotalar ligament were the least prevalent (≈80% and ≈63%, respectively). The longest ligament was found to be the tibionavicular ligament and the shortest band was the deep posterior tibiotalar ligament. The tibionavicular ligament was the thinnest of all deltoid complex ligament components. This study yielded more accurate data on the frequency and size of its components. The possible absence of a component, particularly of the superficial layer, might compromise joint stability in acute ankle injuries.

LEVELS OF EVIDENCE

Systematic review of level III studies: prospective studies.

BIMALLEOLAR ANKLE FRACTURE: A SIMPLE FRACTURE?

OBJECTIVE

To evaluate the frequency of deltoid ligament injury in bimalleolar supination-external rotation type fractures and whether there is a correlation between the size of the fractured medial malleolus and deltoid ligament injury .

METHODS

Twenty six consecutive patients underwent magnetic resonance exams after clinical and radiographic diagnosis of bimalleolar supination-external rotation type ankle fractures .

RESULTS

Thirteen patients (50%) presented deltoid ligament injury associated to bimalleolar ankle fracture. Partial injury was present in seven (26.9%) patients and total injury in six (23.1%). Regarding medial fragment size, the average was 2.88 cm in the absence of deltoid ligament injury. Partial injuries presented 1.93 cm and total 2.1 cm on average .

CONCLUSION

Deltoid ligament injury was present in 50% of bimalleolar ankle fractures. Smaller medial malleolus fragments, especially concerning the anterior colliculus, presented greater association with partial deltoid ligament injuries. Level of Evidence IV, Cross Sectional Study.

Repair of Acute Superficial Deltoid Complex Avulsion During Ankle Fracture Fixation in National Football League Players

BACKGROUND

Infolding and retraction of an avulsed deltoid complex after ankle fracture can be a source of persistent increased medial clear space, malreduction, and postoperative pain and medial instability. The purpose of this descriptive case series was to analyze the preliminary outcomes of acute superficial deltoid complex avulsion repair during ankle fracture fixation in a cohort of National Football League (NFL) players. We found that there is often complete avulsion of the superficial deltoid complex off the proximal aspect of the medial malleolus during high-energy ankle fractures in athletes.

METHODS

Between 2004 and 2014, the cases of 14 NFL players who underwent ankle fracture fixation with open deltoid complex repair were reviewed. Patients with chronic deltoid ligament injuries or ankle fractures more than 2 months old were excluded. Average age for all patients was 25 years and body mass index 34.4. Player positions included 1 wide receiver, 1 tight end, 1 safety, 1 running back, 1 linebacker, and 9 offensive linemen. Average time from injury to surgery was 7.5 days. Surgical treatment for all patients consisted of ankle arthroscopy and debridement, followed by fibula fixation with plate and screws, syndesmotic fixation with suture-button devices, and open deltoid complex repair with suture anchors. Patient demographics were recorded with position played, time from injury to surgery, games played before and after surgery, ability to return to play, and postoperative complications. Return to play was defined as the ability to successfully participate in at least 1 full regular-season NFL game after surgery.

RESULTS

All NFL players were able to return to running and cutting maneuvers by 6 months after surgery. There were no significant differences in playing experience before surgery versus after surgery. Average playing experience before surgery was 3.3 seasons, 39 games played, and 22 games started. Average playing experience after surgery was 1.6 seasons, 16 games played, and 15 games started. Return to play was 86% for all players. There were no intraoperative or postoperative complications noted, and no players had clinical evidence of medial pain or instability at final follow-up with radiographic maintenance of anatomic mortise alignment.

CONCLUSION

Superficial deltoid complex avulsion during high-energy ankle fractures in athletes is a distinct injury pattern that should be recognized and may benefit from primary open repair. The majority of NFL players treated surgically for this injury pattern are able to return to play after surgery with no reported complications or persistent medial ankle pain or instability.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Guesstimation of posterior malleolar fractures on lateral plain radiographs

BACKGROUND

Accurate assessment of articular involvement of the posterior malleolar fracture fragments in ankle fractures is essential, as this is the leading argument for internal fixation. The purpose of this study is to assess diagnostic accuracy of measurements on plain lateral radiographs.

METHODS

Quantification of three-dimensional computed tomography (Q-3D-CT) was used as a reference standard for true articular involvement (mm(2)) of posterior malleolar fractures. One-hundred Orthopaedic Trauma surgeons were willing to review 31 trimalleolar ankle fractures to estimate size of posterior malleolus and answer: (1) what is the involved articular surface of the posterior malleolar fracture as a percentage of the tibial plafond? and (2) would you fix the posterior malleolus?

RESULTS

The average posterior malleolar fragment involved 13.5% (SD 10.8) of the tibial plafond articular surface, as quantified using Q-3D-CT. The average involvement of articular surface of the posterior malleolar fragment, as estimated by 100 observers on plain radiographs was 24.4% (SD 10.0). The factor 1.8 overestimation of articular involvement was statistically significant (p<0.001). Diagnostic accuracy of measurements on plain lateral radiographs was 22%. Interobserver agreement (ICC) was 0.61. Agreement on operative fixation, showed an ICC of 0.54 (Haraguchi type I=0.76, Haraguchi type II=0.40, Haraguchi type III=0.25).

CONCLUSIONS

Diagnostic accuracy of measurements on plain lateral radiographs to assess articular involvement of posterior malleolar fractures is poor. There is a tendency to misjudge posteromedial involvement (Haraguchi type II).

Osteoligamentous injuries of the medial ankle joint

Injuries of the ankle joint have a high incidence in daily life and sports, thus, playing an important socioeconomic role. Therefore, proper diagnosis and adequate treatment are mandatory. While most of the ligament injuries around the ankle joint are treated conservatively, great controversy exists on how to treat deltoid ligament injuries in ankle fractures. Missed injuries and inadequate treatment of the medial ankle lead to inferior outcome with instability, progressive deformity, and ankle joint osteoarthritis.

Closed Medial Malleolar Multifragment Fracture With a Posterior Tibialis Tendon Rupture: A Case Report and Review of the Literature

Ankle fractures represent an exciting field of traumatology because of the wide variety of clinical presentations, injury mechanisms, and treatment options. Rupture of the posterior tibialis tendon (PTT) with ankle fracture can occur during trauma that involves pronation and external rotation of the foot or, less commonly, secondary to direct trauma to the ankle. This tendon injury is uncommon and probably misdiagnosed in many cases, because of the difficult clinical examination secondary to the pain and swelling. The identification and early treatment of PTT tears is essential for good functional outcomes to prevent the main mid- to long-term complication of disabling acquired flatfoot due to tendon failure. In the present report, we provide a review of the published data regarding ankle fractures associated with PTT rupture and describe our experience with a case of a multifragment medial malleolus fracture and complete rupture of the PTT diagnosed intraoperatively and surgically treated in a 34-year-old male, with 2.5 years of follow-up.

Lagged Syndesmotic Fixation: Our Clinical Experience

Ankle fractures are very common, and although algorithms are in place for osseous management, consensus has not been reached regarding treatment of associated ligamentous injuries. Although tibiofibular syndesmotic stabilization can be done using different forms of fixation, the biomedical literature has long emphasized the risk of long-term restriction of ankle mobility with the use of lagged transfixation. However, when reduction cannot be maintained with positional fixation, we found that lagging the syndesmotic screw helped to maintain the reduction without causing functional restriction. In this report, we describe our experience with patients who had undergone lagged tibiofibular transfixation and were available for short- to intermediate-term follow-up to assess ankle function. A total of 31 patients (32.63% of 95 consecutive patients) were available at a mean of 34.87 (range 18 to 52) months to complete the American Orthopedic Foot and Ankle Society ankle-hindfoot questionnaire. The mean score was 88.38 (range 42 to 100) points at a mean follow-up interval of 34.87 (range 18 to 52) months. Of 31 patients, 19 had an AOFAS score of 90 points, 9 an AOFAS score of 80 to 89 points, 2 an AOFAS score of 60 to 69 points, and 1 an AOFAS score of <60 points. Because all syndesmotic screws were placed using the lag technique, unrestricted motion compared with the uninjured limb was used as the endpoint. All subjects had unrestricted motion compared with the uninjured limb, refuting the assertion that lagged syndesmotic screw fixation confers more restriction in ankle kinematics than positional syndesmotic fixation.

Effect of syndesmosis injury in SER IV (Weber B)-type ankle fractures on function and incidence of osteoarthritis

BACKGROUND

Syndesmosis fixation of Lauge-Hansen SER IV, Weber B ankle fractures is controversial. This study compared a matched pair of SER IV patients with stress proven syndesmotic injuries with the same number without stress proven syndesmotic injury in terms of functional, pain, and radiologic result.

METHODS

The study was based on a RCT-study comparing syndesmotic transfixation to no fixation in SER IV (Weber B)-type ankle fractures. Twenty-four patients with a syndesmosis injury found on the intraoperative 7.5 Nm standardized external rotation test were compared to 24 patients with a stable syndesmosis. The pairs were matched by fracture morphology, sex, and age. The primary outcome measure was ankle function as assessed by the Olerud-Molander score. Weight-bearing plain radiographs and 3T MRI of the injured ankle were used to assess ankle joint congruity and osteoarthritis, according to Kellgren-Lawrence classification and cartilage defects.

RESULTS

The Olerud-Molander score was 86 in syndesmosis injury patients and 90 in patients with normal syndesmosis (P = .28). The incidence of ankle joint osteoarthritis on plain radiographs was not significantly different between the groups (Grade I 5% vs 21%; Grade II 86% vs 75%; Grade III 9% vs 4%; P = .34). MRI scans showed TC joint cartilage defects in 54% of the patients: 12 (56%) in the syndesmosis injury group vs 13 (54%) in the group without syndesmosis injury (P > .9).

CONCLUSION

After 4 to 6 years of follow-up, clinical and radiologic outcome were not different in patients with syndesmosis injury compared to patients with stable syndesmosis in SER IV (Weber B)-type ankle fractures.

LEVEL OF EVIDENCE

Prognostic Level II, comparative study.

Repair of the acute deltoid ligament complex rupture associated with ankle fractures: a multicenter clinical study

Controversy exists concerning the need for operative repair of the deltoid ligament during management of acute ankle fractures. The purpose of our report was to identify the indications for surgical intervention for deltoid ligament injury in the setting of ankle fractures. Furthermore, we aimed to elucidate the clinical outcomes after deltoid ligament repair in this setting. This was a multicenter study, involving 4 clinical institutions. From January 2006 to December 2011, 1533 ankle fractures underwent surgical intervention. Of this group, 131 deltoid ligament ruptures (8.55%) were identified and repaired operatively. Of the 131 patients, 74 were male (56.5%) and 57 were female (43.5%), with a mean age of 33.2 (range 16 to 63) years. The outcome measures included the clinical examination findings, radiographic findings, American Orthopaedic Foot and Ankle Society ankle-hindfoot scores, visual analog scale (VAS) scores, and Medical Outcomes Study Short Form 36-item questionnaire scores. All incisions healed primarily. A total of 106 patients were followed up for a minimum of 12 (range 12 to 72) months, with an average follow-up period of 27 months. The mean interval to fracture union was 14.5 (range 9 to 16) weeks. The mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score at the latest follow-up visit was 91.4 (range 83 to 100) points. The mean visual analog scale score was 1.2 (range 0 to 6) points. The mean Short Form-36 score was 91.2 (range 80 to 96) points. Compared with the preoperative scores, all the 3 outcome measures had improved significantly postoperatively (p < .05). The postoperative stress radiographs did not reveal any ankle instability. None had evidence of post-traumatic arthritis of the ankle from the clinical examination and radiographs. A reasonable clinical evaluation and surgical repair was executed, with an appropriate repair technique chosen according to the site of deltoid ligament rupture. The results of the present multicenter study have shown that deltoid ligament rupture can be repaired in patients with an unstable medial ankle after fracture fixation and prevent ankle stabilization-related complications.

Anatomic study of the deltoid ligament of the ankle

BACKGROUND

There is heterogeneity in the literature regarding the anatomy and number of ligamentous bands that form the deltoid ligament (DL). Anatomic knowledge of the DL and its variations are important for surgeons who repair ankle fractures.

METHODS

The DL was dissected in 33 ankles from 17 formalin-fixed cadavers (mean age at death, 76.6 years) to examine its morphology. The length, width, and thickness of its constituent bands were recorded with a digital caliper. Descriptive and correlational statistics were used to investigate the relationships between band size, age at death, and sex. A literature review was conducted to compare our data to those of previous studies.

RESULTS

The DL has superficial and deep layers with up to 8 different bands.

CONCLUSION

The DL stabilizes the medial ankle and should be evaluated in flatfoot deformities and severe ankle fractures.

CLINICAL RELEVANCE

Anatomic knowledge of DL variations should aid the surgeon in repairing torn DLs.

Nonoperative treatment of the medial malleolus in bimalleolar and trimalleolar ankle fractures: a randomized controlled trial

OBJECTIVES

To compare internal fixation with no fixation of the medial malleolus after open reduction and internal fixation of the lateral malleolus and if needed, the posterior malleolus.

DESIGN

Randomized prospective trial.

SETTING

Level III trauma center in a metropolitan area.

PATIENTS

One hundred patients with bimalleolar or trimalleolar Orthopaedic Trauma Association type 44 ankle fractures and displacement of the medial malleolus less than 2 mm after open reduction and internal fixation of the lateral component.

INTERVENTION

Internal fixation or nonoperative treatment of the medial malleolus.

MAIN OUTCOME MEASUREMENTS

American Orthopaedic Foot and Ankle Society ankle hind foot score (AOFAS), The Olerud Molander Ankle (OMA) score, and visual analogue pain scale (VAS).

RESULTS

Median follow-up time was 39 months (range: 24-72). There were no significant differences between the 2 groups with respect to OMA (P = 0.91), AOFAS (P = 0.85), VAS (P = 0.85), or development of osteoarthritis (P = 0.22). Reoperation and complication rates were also comparable, but 4 patients treated nonoperatively developed nonunion of the medial malleolus. These patients reported no functional disabilities and presented OMA, AOFAS, and VAS scores better than average.

CONCLUSIONS

Our data indicate that nonoperative treatment of minimally displaced fractures of the medial malleolus after operative fixation of the fibula yields satisfactory results. However, long-term follow-up is needed due to increased risk of nonunion and uncertainty regarding the development of posttraumatic arthritis.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Tibialis posterior tendon and deltoid and spring ligament injuries in the elite athlete

The tibialis posterior tendon and the spring and deltoid ligament complexes combine to provide dynamic and passive stabilization on the medial side of the ankle and hindfoot. Some of the injuries will involve acute injury to previous healthy structures, but many will develop insidiously. The clinician must be aware of new treatment strategies and the level of accompanying scientific evidence regarding injuries sustained by athletes in these areas, while acknowledging that more traditional management applied to nonathletic patients is still likely to be appropriate in the setting of treatment for elite athletes.

Varus external rotation stress test for radiographic detection of deep deltoid ligament disruption with and without syndesmotic disruption: a cadaveric study

BACKGROUND

External rotation stress is used intraoperatively for diagnosing medial ankle and syndesmotic instability in rotational ankle fractures after reduction and fixation of the fibula. However, external rotation includes hindfoot, midfoot, and ankle motion. The purpose of this study was to determine the effect of hindfoot positioning when using the external rotation stress test. Isolated deep deltoid ligament (DDL) instability and combined DDL and syndesmotic instability were modeled. An intact fibula was used as a surrogate for an anatomically fixed fibula fracture.

METHODS

Six cadaver specimens with full-length tib-fib articulations were used. Specimens were fixed into a Taylor Spatial Frame (Smith&Nephew, Memphis, TN) with 4 to 5 points of fixation in the tibia and the foot. Specimens were mounted in ankle and foot neutral position. Metal markers were placed at the medial gutter and syndesmosis. Anteroposterior (AP) and mortise radiographs were obtained in 3 positions: neutral hindfoot, valgus external rotation stress, and varus external rotation stress. For both valgus and varus external rotation stress, the frame was loosened and stressed to a hard end point and then locked. Three modes were studied: intact ligaments, DDL transected, and DDL+ syndesmosis transected. Digital radiographs were used to measure the displacement of the markers.

RESULTS

The varus external rotation stress test demonstrated significant widening of the medial gutter in specimens with isolated DDL instability, in both AP (P = .01) and mortise (P = .02) views. Both maneuvers demonstrated significant medial gutter widening with combined DDL and syndesmosis disruption (P ≤ .01), although the varus external rotation stress test produced nearly twice as much displacement (10.7 vs 5.4 mm). Syndesmotic widening was not significant with either maneuver.

CONCLUSIONS

Varus external rotation stress was more effective than valgus external rotation stress in demonstrating displacement of markers at the medial gutter and on AP and mortise radiographs for both DDL and DDL with syndesmotic instability.

CLINICAL RELEVANCE

These findings may lead to improved clinical detection of rotational ankle instability from combined DDL and syndesmotic disruption, which may affect decision making for using syndesmotic fixation when using intraoperative stress fluoroscopy images. Occult DDL instability may be underdiagnosed, and this may affect future directions of the treatment of rotational ankle fractures and severe sprains.

Biomechanics of the normal and arthritic ankle joint

Understanding biomechanics of the normal and arthritic ankle joint can aid in analysis of an underlying clinical problem and provide a strategic basis for a more optimal management. The challenge to the clinician and the biomechanist is that the mechanical complexity of the ankle joint still clouds current understanding. This article provides an overview of current understanding of functional ankle anatomy, how this function can be altered in the degenerated ankle, and how surgical intervention further affects foot and ankle biomechanics. The focus is on how altered loading of neighboring joints in the midfoot and hindfoot may induce postoperative joint remodeling and can manifest in secondary clinical problems.

Stability-based classification for ankle fracture management and the syndesmosis injury in ankle fractures due to a supination external rotation mechanism of injury

The aim of this thesis was to confirm the utility of stability-based ankle fracture classification in choosing between non-operative and operative treatment of ankle fractures, to determine how many ankle fractures are amenable to non-operative treatment, to assess the roles of the exploration and anatomical repair of the AITFL in the outcome of patients with SER ankle fractures, to establish the sensitivities, specificities and interobserver reliabilities of the hook and intraoperative stress tests for diagnosing syndesmosis instability in SER ankle fractures, and to determine whether transfixation of unstable syndesmosis is necessary in SER ankle fractures. The utility of stability based fracture classification to choose between non-operative and operative treatment was assessed in a retrospective study (1) of 253 ankle fractures in skeletally mature patients, 160 of whom were included in the study to obtain an epidemiological profile in a population of 130,000. Outcome was assessed after a minimum follow-up of two years. The role of AITFL repairs was assessed in a retrospective study (2) of 288 patients with Lauge-Hansen SE4 ankle fractures; the AITFL was explored and repaired in one group (n=165), and a similar operative method was used but the AITFL was not explored in another group (n=123). Outcome was measured with a minimum follow-up of two years. Interobserver reliability of clinical syndesomosis tests (study 3) and the role of syndesmosis transfixation (study 4) were assessed in a prospective study of 140 patients with Lauge-Hansen SE4 ankle fractures. The stability of the distal tibiofibular joint was evaluated by the hook and ER stress tests. Clinical tests were carried out by the main surgeon and assistant, separately, after which a 7.5-Nm standardized ER stress test for both ankles was performed; if it was positive, the patient was randomized to either syndesmosis transfixation (13 patients) or no fixation (11 patients) treatment groups. The sensitivity and specificity of both clinical tests were calculated using the standard 7.5-Nm external rotation stress test as reference. Outcome was assessed after a minimum of one year of follow-up. Olerud-Molander (OM) scoring system, RAND 36-Item Health Survey, and VAS to measure pain and function were used as outcome measures in all studies. In study 1, 85 (53%) fractures were treated operatively using the stability based fracture classification. Non-operatively treated patients reported less pain and better OM (good or excellent 89% vs. 71%) and VAS functional scores compared to operatively treated patients although they experienced more displacement of the distal fibula (0 mm 30% vs. 69%; 0-2 mm 65% vs. 25%) after treatment. No non-operatively treated patients required operative fracture fixation during follow-up. In study 2, AITFL exploration and suture lead to equal functional outcome (OM mean, 77 vs. 73) to no exploration or fixation. In study 3, the hook test had a sensitivity of 0.25 and a specificity of 0.98. The external rotation stress test had a sensitivity of 0.58 and a specificity of 0.9. Both tests had excellent interobserver reliability; the agreement was 99% for the hook test and 98% for the stress test. There was no statistically significant difference in functional scores (OM mean, 79.6 vs. 83.6) or pain between syndesmosis transfixation and no fixation groups (Study 4). Our results suggest that a simple stability-based fracture classification is useful in choosing between non-operative and operative treatment of ankle fractures; approximately half of the ankle fractures can be treated non-operatively with success. Our observations also suggest that relevant syndesmosis injuries are rare in ankle fractures due to an SER mechanism of injury. According to our research, syndesmotic repair or fixation in SER ankle fracture has no influence on functional outcome or pain after minimum one year compared with no fixation.

The diagnosis and treatment of deltoid ligament lesions in supination-external rotation ankle fractures: a review

The supination–external rotation or Weber B type fracture exists as a stable and an unstable type. The unstable type has a medial malleolus fracture or deltoid ligament lesion in addition to a fibular fracture. The consensus is the unstable type and best treated by open reduction and internal fixation. The diagnostic process for a medial ligament lesion has been well investigated but there is no consensus as to the best method of assessment. The number of deltoid ruptures as a result of an external rotation mechanism is higher than previously believed. The derivation of the injury mechanism could provide information of the likely ligamentous lesion in several fracture patterns. The use of the Lauge-Hansen classification system in the assessment of the initial X-ray images can be helpful in predicting the involvement of the deltoid ligament but the reliability in terms of sensitivity and specificity is unknown. Clinical examination, stress radiography, magnetic resonance imaging, arthroscopy, and ultrasonography have been used to investigate medial collateral integrity in cases of ankle fractures. None of these has shown to possess the combination of being cost-effective, reliable and easy to use; currently gravity stress radiography is favoured and, in cases of doubt, arthroscopy could be of value. There is a disagreement as to the benefit of repair by suture of the deltoid ligament in cases of an acute rupture in combination with a lateral malleolar fracture. There is no evidence found for suturing but exploration is thought to be beneficial in case of interposition of medial structures.

Syndesmotic fixation in supination-external rotation ankle fractures: a prospective randomized study

BACKGROUND

This study was designed to assess whether transfixion of an unstable syndesmosis is necessary in supination-external rotation (Lauge-Hansen SE/Weber B)-type ankle fractures.

METHODS

A prospective study of 140 patients with unilateral Lauge-Hansen supination-external rotation type 4 ankle fractures was done. After bony fixation, the 7.5-Nm standardized external rotation (ER) stress test for both ankles was performed under fluoroscopy. A positive stress examination was defined as a difference of more than 2 mm side-to-side in the tibiotalar or tibiofibular clear spaces on mortise radiographs. If the stress test was positive, the patient was randomized to either syndesmotic transfixion with 3.5-mm tricortical screws or no syndesmotic fixation. Clinical outcome was assessed using the Olerud-Molander scoring system, RAND 36-Item Health Survey, and Visual Analogue Scale (VAS) to measure pain and function after a minimum 1-year of followup.

RESULTS

Twenty four (17%) of 140 patients had positive standardized 7.5-Nm ER stress tests after malleolar fixation. The stress view was positive three times on tibiotalar clear space, seven on tibiofibular clear space, and 14 times on both tibiotalar and tibiofibular clear spaces. There was no significant difference between the two randomization groups with regards to Olerud-Molander functional score, VAS scale measuring pain and function, or RAND 36-Item Health Survey pain or physical function at 1 year.

CONCLUSION

Relevant syndesmotic injuries are rare in supination-external rotation ankle fractures, and syndesmotic transfixion with a screw did not influence the functional outcome or pain after the 1-year followup compared with no fixation.

Intraoperative assessment of the stability of the distal tibiofibular joint in supination-external rotation injuries of the ankle: sensitivity, specificity, and reliability of two clinical tests

BACKGROUND

This study was designed to assess the sensitivity, specificity, and interobserver reliability of the hook test and the stress test for the intraoperative diagnosis of instability of the distal tibiofibular joint following fixation of ankle fractures resulting from supination-external rotation forces.

METHODS

We conducted a prospective study of 140 patients with an unstable unilateral ankle fracture resulting from a supination-external rotation mechanism (Lauge-Hansen SE). After internal fixation of the malleolar fracture, a hook test and an external rotation stress test under fluoroscopy were performed independently by the lead surgeon and assisting surgeon, followed by a standardized 7.5-Nm external rotation stress test of each ankle under fluoroscopy. A positive stress test result was defined as a side-to-side difference of >2 mm in the tibiotalar or the tibiofibular clear space on mortise radiographs. The sensitivity and specificity of each test were calculated with use of the standardized 7.5-Nm external rotation stress test as a reference.

RESULTS

Twenty-four (17%) of the 140 patients had a positive standardized 7.5-Nm external rotation stress test after internal fixation of the malleolar fracture. The hook test had a sensitivity of 0.25 (95% confidence interval, 0.12 to 0.45) and a specificity of 0.98 (95% confidence interval, 0.94 to 1.0) for the detection of the same instabilities. The external rotation stress test had a sensitivity of 0.58 (95% confidence interval, 0.39 to 0.76) and a specificity of 0.96 (95% confidence interval, 0.90 to 0.98). Both tests had excellent interobserver reliability, with 99% agreement for the hook test and 98% for the stress test.

CONCLUSIONS

Interobserver agreement for the hook test and the clinical stress test was excellent, but the sensitivity of these tests was insufficient to adequately detect instability of the syndesmosis intraoperatively.

Ultrasonography as a diagnostic tool in assessing deltoid ligament injury in supination external rotation fractures of the ankle

The medial deltoid ligament is the primary stabilizing structure in the ankle joint following lateral malleolar fracture. However, medial deltoid ligament ruptures are difficult to diagnose using current imaging modalities. We hypothesized that ultrasonography can be used to accurately allow early clinical assessment of ankle fracture stability, thereby negating the need to perform plain film stress views of the acutely injured ankle. This prospective study included 12 patients (age range, 18-72) with supination external rotation fractures requiring operative fixation. Following induction of anesthesia, ultrasonography examination was performed, followed by an arthrogram under fluoroscopic screening. Radiographs, ultrasonography, and arthrographic findings were compared. There was 100% correlation between ultrasonography and arthrogram findings. Ultrasonography accurately diagnosed medial deltoid rupture with a sensitivity of 100% and specificity of 100%. Plain film radiographs of the ankle had a sensitivity of 57.1% and a specificity of 60%. The difference between these was significant (χ(2)=.0091). This study demonstrates diagnostic ultrasonography to be an accurate diagnostic modality in assessing medial deltoid ligament integrity in patients with supination external rotation fractures. It offers the same sensitivity and specificity as arthrography without the need for additional invasive procedures. Its relative ease of use and lack of ionizing radiation make it a potentially useful tool, particularly in a busy trauma service.

Long-term outcome after supination-external rotation type-4 fractures of the ankle

We have compared the results at a mean follow-up of 13 years (11 to 14) of two groups of supination-external rotation type-4 fractures of the ankle, in one of which there was a fracture of the medial malleolus and in the other the medial deltoid ligament had been partially or completely ruptured.

Of 66 patients treated operatively between 1993 and 1997, 36 were available for follow-up. Arthroscopy had been performed in all patients pre-operatively to assess the extent of the intra-articular lesions. The American Orthopaedic Foot and Ankle Society hind-foot score was used for clinical evaluation and showed a significant difference in both the total and the functional scores (p < 0.05), but not in those for pain or alignment, in favour of the group with a damaged deltoid ligament (p < 0.05). The only significant difference between the groups on the short-form 36 quality-of-life score was for bodily pain, again in favour of the group with a damaged deltoid ligament. There was no significant difference between the groups in the subjective visual analogue scores or in the modified Kannus radiological score.

Arthroscopically, there was a significant difference with an increased risk of loose bodies in the group with an intact deltoid ligament (p < 0.005), although there was no significant increased risk of deep cartilage lesions in the two groups.

At a mean follow-up of 13 years after operative treatment of a supination-external rotation type-4 ankle fracture patients with partial or complete rupture of the medial deltoid ligament tended to have a better result than those with a medial malleolar fracture.

Comparison of two intraoperative assessment methods for injuries to the ankle syndesmosis. A cadaveric study

BACKGROUND

Intraoperative stress testing is required for the detection of syndesmosis instability following an ankle fracture. The present study compared two stress tests for the detection of syndesmotic injury.

METHODS

A true mortise radiograph of the ankle was made for fourteen cadaver joints. Specimens were randomized into two groups to simulate ligament and syndesmosis injury on the basis of the Danis-Weber classification system. In the first group, the anterior inferior tibiofibular ligament was divided first (Weber B(r)), followed sequentially by division of the interosseous membrane (Weber C) and the deltoid ligament. In the second group, the deltoid ligament was divided first, followed by the anterior inferior tibiofibular ligament. Radiographs were made at each stage with use of two methods of stressing the ankle mortise: (1) external rotation of the foot with an external moment of 7.5 Nm, and (2) application of a lateral force of 100 N. Tibiofibular overlap, tibiofibular clear space, and medial clear space were measured.

RESULTS

Lateral stress produced a significantly greater increase in the tibiofibular clear space than did the external rotation test for Weber C injuries and Weber C plus deltoid ligament injuries. A greater increase in the tibiofibular clear space was noted during the lateral stress test when both the deltoid and the anterior inferior tibiofibular ligament had been sectioned (p < 0.05). The external rotation stress test produced a significant increase in the medial clear space in the presence of isolated anterior inferior tibiofibular ligament and deltoid ligament injuries (p < 0.05).

CONCLUSIONS

For the detection of syndesmotic instability at the site of ankle fractures on stress radiographs, the lateral stress test appeared to be superior to the external rotation stress test in this cadaver model.

Distal fibula malunions

Anatomic reduction and fixation of unstable ankle fractures is necessary to prevent posttraumatic arthritis. Malunion of the distal fibula in unstable ankle fractures may lead to progressive talar instability. Ankle fracture malunions often present with concomitant syndesmotic widening, which can cause surgeons to overlook changes in fibula length and rotation. The decision to proceed with surgery should be made only after a careful diagnostic workup and detailed preoperative discussion with the patient. Considerations for surgical management include location and orientation of a corrective osteotomy, use of structural graft, widening of the syndesmosis, assessment of reduction, and the need for medial exposure. Good and excellent clinical results after fibular reconstruction have been reported in 67% to 92% of ankles. Proper patient selection is critical, because ankle malunions can be complicated, with coexisting fibular, syndesmotic, medial, and posterior malleolar malalignment, along with degenerative joint disease. Understanding the indications and surgical technique for revising fibular malunions may obviate a future salvage procedure.

Evaluation of the integrity of the deltoid ligament in supination external rotation ankle fractures: a systematic review of the literature

BACKGROUND AND PURPOSE

Review the literature concerning modalities to evaluate the integrity of the deltoid ligament in patients with supination external rotation ankle fractures.

METHODS

The electronic databases Pubmed/Medline, CINAHL and Embase were searched from 1987 to November 2007 to identify all published original studies concerning diagnostic modalities to evaluate the integrity of the deltoid ligament in adult ankle fractures.

RESULTS

This review included nine studies involving 423 ankle fractures. Three trails investigated medial tenderness; two studies, ecchymosis; two studies, swelling; one study, an injury radiograph; six studies, a type of radiographic stress view; one study, the Lauge-Hansen classification; one study, MRI; and one article studied arthroscopy in the evaluation of the deltoid ligament integrity.

INTERPRETATION

Swelling, ecchymosis, medial tenderness, initial injury radiographs and the Lauge-Hansen classification are less adequate predictors of the integrity of the deltoid ligament. Manual or the less painful variant, the gravity external rotation stress radiographs are considered the gold standard. The amount of medial clear space widening indicative of a positive external rotation stress test has been somewhat variable in the literature but > or =5 mm is generally regarded as most reliable. Achieving adequate external rotation of the foot when obtaining stress radiographs is more important than positioning the ankle in the appropriate degree of ankle flexion. The amount of applied force necessary when performing an external rotation stress radiograph is not well defined and mainly determined by the patient's pain level. The indication for surgery should not be based on the absolute value of one parameter but on the combination of several parameters. If nonoperative treatment is chosen despite a positive stress radiograph, close follow-up is critical because subluxation of the ankle joint is still possible. MRI could be useful in individual cases.

A rational approach to ankle fractures

Ankle fractures involve a spectrum of injury patterns from simple to complex, such that these injuries are not always "just an ankle fracture." By combining the injury mechanism and the radiographic findings, the surgeon can apply the Lauge-Hansen classification in taking a rational approach to the management of these fractures. Syndesmotic instability and atypical patterns are becoming increasingly recognized, in part through the judicious use of CT scans. The goal of surgical stabilization includes atraumatic soft tissue management, rigid internal fixation, and early range of motion exercises in maximizing return of function.

Extraperiosteal plating of pronation-abduction ankle fractures. Surgical technique

BACKGROUND

Pronation-abduction ankle fractures frequently are associated with substantial lateral comminution and have been reported to be associated with the highest rates of nonunion among indirect ankle fractures. The purpose of the present study was to report the technique for and outcomes of extraperiosteal plating in a series of patients with pronation-abduction ankle fractures.

METHODS

Thirty-one consecutive patients with an unstable comminuted pronation-abduction ankle fracture were managed with extraperiosteal plating of the fibular fracture. The average age of the patients was forty-four years. There were nineteen bimalleolar and twelve lateral malleolar fractures with an associated deltoid ligament injury. No attempt to reduce the comminuted fragments was made as this area was spanned by the plate. The patients were evaluated functionally (with use of the American Orthopaedic Foot and Ankle Society score), radiographically, and clinically (with range-of-motion testing).

RESULTS

Immediate postoperative and final follow-up radiographs showed that all patients had a well-aligned ankle mortise on the fractured side as compared with the normal side on the basis of standardized measurements. All fractures healed without displacement. At a minimum of two years after the injury, the average American Orthopaedic Foot and Ankle Society score (available for twenty-one patients) was 82. The range of motion averaged 13 degrees of dorsiflexion and 31 degrees of plantar flexion, with one patient not achieving dorsiflexion to neutral. There were no deep infections, and one patient had an area of superficial skin breakdown that healed without operative intervention.

CONCLUSIONS

Extraperiosteal plating of pronation-abduction ankle fractures is an effective method of stabilization that leads to predictable union of the fibular fracture. The results of this procedure are at least as good as those of other techniques of open reduction and internal fixation of the ankle, although specific results for pronation-abduction injuries have not been previously reported, to our knowledge.

Nonoperative treatment of bimalleolar equivalent ankle fractures: a retrospective review of 51 patients

The purpose of this retrospective study was to determine the outcome of bimalleolar equivalent ankle fractures in patients who were treated nonoperatively. The charts of 214 patients with isolated Weber B (supination-external rotation pattern) fibula fractures were reviewed. Fifty-one patients met the inclusion criteria and were administered the American Orthopaedic Foot and Ankle Society Ankle and Hindfoot Functional Survey by telephone or personal interview. The average medial clear space was 5.09 mm; the average American Orthopaedic Foot and Ankle Society Ankle and Hindfoot Functional Survey score was 84.22. A medial clear space of 4, 5, 6, and 7 mm resulted in American Orthopaedic Foot and Ankle Society Ankle and Hindfoot Functional Survey scores of 90.22, 89.4, 72.0 and 63.17, respectively. Further analysis showed significant differences in American Orthopaedic Foot and Ankle Society Ankle and Hindfoot Functional Survey scores between the 4 mm medial clear space group and the 6 mm and 7 mm medial clear space groups; the 5 mm medial clear space group and the 6 mm and 7 mm groups. Our results suggest that medial tenderness and ecchymosis alone are not sufficient to meet operative criteria, a higher medial clear space on stress gravity views correlates with a lower American Orthopaedic Foot and Ankle Society Ankle and Hindfoot Functional Survey score, and that there are significant differences in American Orthopaedic Foot and Ankle Society Ankle and Hindfoot Functional Survey scores between groups with medial clear space 4 to 7 mm. ACFAS Level of Clinical Evidence: 2b.

Syndesmotic instability in Weber B ankle fractures: a clinical evaluation

OBJECTIVE

Syndesmotic instability may coexist with unstable Weber B supination-external rotation (SE) lateral malleolar fractures. Current recommendations suggest that Weber B injuries should not have associated syndesmotic instability after open reduction and internal fixation of the lateral malleolus. The purpose of this study was to evaluate syndesmotic stability with respect to the current recommendations for syndesmotic fixation in Weber B SE pattern lateral malleolar fractures.

DESIGN

Retrospective cohort, consecutive series.

SETTING

Academic Level I trauma center.

PATIENTS/PARTICIPANTS

Over a 7-year period, 238 skeletally mature patients with unstable SE pattern Weber B lateral malleolus fractures with deltoid ligament incompetence were evaluated.

INTERVENTION

After lateral malleolar fixation, syndesmotic stability was evaluated by an external rotation stress examination under direct vision and fluoroscopy.

MAIN OUTCOME MEASURES

The incidence of syndesmotic instability as defined by previously reported criteria.

RESULTS

Syndesmotic instability was found in 93 of the 238 (39%) fractures after fixation. Instability was identified in the operating room in 92 of the 93 ankles. One case of instability was missed intraoperatively and diagnosed 2 weeks after surgery. All other patients were followed to union without displacement.

CONCLUSIONS

We found syndesmotic instability to be common after anatomic and stable bony fixation in unstable Weber B SE pattern lateral malleolar fractures. Previously published criteria for syndesmotic instability based on cadaveric studies are not representative of the clinical situation. Syndesmotic instability in conjunction with unstable Weber B SE pattern lateral malleolar fractures must be sought out in the operating room with an intraoperative stress examination.

Ankle syndesmotic injury

Ankle syndesmotic injury does not necessarily lead to ankle instability; however, the coexistence of deltoid ligament injury critically destabilizes the ankle joint. Syndesmotic injury may occur in isolation or may be associated with ankle fracture. In the absence of fracture, physical examination findings suggestive of injury include ankle tenderness over the anterior aspect of the syndesmosis and a positive squeeze or external rotation test. Radiographic findings usually include increased tibiofibular clear space decreased tibiofibular overlap, and increased medial clear space. However, syndesmotic injury may not be apparent radiographically; thus, routine stress testing is necessary for detecting syndesmotic instability. The goals of management are to restore and maintain the normal tibiofibular relationship to allow for healing of the ligamentous structures of the syndesmosis. Fixation of the syndesmosis is indicated when evidence of a diastasis is present. This may be detected preoperatively, in the absence of fracture, or intraoperatively, after rigid fixation of the medial malleolus and fibula fractures. Failure to diagnose and stabilize syndesmotic disruption adversely affects outcome.

Comparison of manual and gravity stress radiographs for the evaluation of supination-external rotation fibular fractures

BACKGROUND

Isolated distal fibular fractures most commonly result from a supination-external rotation injury of the ankle. Deltoid ligament ruptures can also be associated with these injuries, resulting in an unstable ankle fracture due to incompetent lateral and medial restraints. We hypothesized that a gravity stress radiograph is equivalent to a manual stress radiograph for the detection of deltoid ligament injury in association with an isolated fibular fracture.

METHODS

All patients presenting to a level-1 trauma hospital emergency department with an isolated fibular fracture were screened. Ankle stability was determined on the basis of radiographic measurements of the medial clear space and talar shift. A manual stress radiograph and a gravity stress radiograph of the injured ankle were made for each patient. The manual stress radiograph was used to determine whether the ankle was stable or unstable.

RESULTS

A total of twenty-five patients (thirteen with a supination-external rotation type-II fracture and twelve with a supination-external rotation type-IV-equivalent injury) were enrolled in the study. In the type-II group, the average medial clear space was 4.15 and 4.26 mm on the manual and gravity stress radiographs, respectively (p = 0.50). In the type-IV group, the average medial clear space was 5.21 and 5.00 mm on the manual and gravity stress radiographs, respectively (p = 0.69).

CONCLUSIONS

The gravity stress radiograph is equivalent to the manual stress radiograph for determining deltoid ligament injury in association with an isolated distal fibular fracture, and thus it can be used to determine ankle stability in patients who present with an isolated distal fibular fracture.

Understanding the superior clear space in the adult ankle

BACKGROUND

The width of the medial clear space often is used to determine the integrity of the deltoid ligament, the primary medial stabilizer of the ankle joint. The normal clinical relationship of the superior clear space to the medial clear space is not well described. This investigation sought to determine if the superior clear space constitutes an accurate point of comparison for the medial clear space and a means for assessing ligamentous stability in an adult ankle.

METHODS

A retrospective review of consecutive ankle radiographs for a 4-month period of time was completed using a university-based radiology database. Using a digitally calibrated ruler, the widths of the medial and superior clear spaces were measured on the mortise view. These values were compared using a Student's t-test.

RESULTS

Digital radiographs of 564 consecutive ankles were reviewed retrospectively and 94 cases were without evidence of trauma, surgery, or degenerative disease. The medial and superior clear spaces were measured on the mortise view and found to be 2.7 mm (standard deviation 0.5; range 1.3 mm to 4.3 mm; 95% confidence interval 1.7 mm to 3.8 mm) and 3.6 mm (standard deviation 0.6; 2.0 to 5.3; CI 2.4 mm to 4.7 mm), respectively. The average absolute difference was 0.9 mm (standard deviation 0.5; -0.7 to 1.5; CI -0.1 mm to 1.8 mm) and in 92 of 94 ankles (98%), the superior clear space was greater than or equal to the medial clear space.

CONCLUSIONS

Understanding the normal radiographic relationship of the superior and medial clear spaces may help in the diagnosis of ligamentous instability in the ankle and may obviate the need for additional diagnostic tests.

Does medial tenderness predict deep deltoid ligament incompetence in supination-external rotation type ankle fractures?

OBJECTIVE

To identify whether medial tenderness is a predictor of deep deltoid ligament incompetence in supination-external rotation ankle fractures.

DESIGN

All Weber B lateral malleolar fractures with normal medial clear space over a 9 month period were prospectively included in the study. Fracture patterns not consistent with a supination-external rotation mechanism were excluded.

SETTING

High-volume tertiary care referral center and Level I trauma center.

PATIENTS/PARTICIPANTS

Fifty-five skeletally mature patients with a Weber B lateral malleolar fracture and normal medial clear space presenting to our institution were included.

INTERVENTION

All study patients had ankle anteroposterior, lateral, and mortise radiographs. Each patient was seen and evaluated by an orthopedic specialist and the mechanism of injury was recorded. Each patient was assessed for tenderness to palpation in the region of the deltoid ligament and then had an external rotation stress mortise radiograph.

MAIN OUTCOME MEASURE

Correlating medial tenderness with deep deltoid competence as measured by stress radiographs.

RESULTS

Thirteen patients (23.6%) were tender medially and had a positive external rotation stress radiograph. Thirteen patients (23.6%) were tender medially and had a negative external rotation stress radiograph. Nineteen patients (34.5%) were nontender medially and had a negative external rotation stress radiograph. Ten patients (18.2%) were nontender medially and had a positive external rotation stress radiograph. We calculated a chi statistic of 2.37 as well as the associated P value of 0.12. Medial tenderness as a measure of deep deltoid ligament incompetence had a sensitivity of 57%, a specificity of 59%, a positive predictive value of 50%, a negative predictive value of 66%, and an accuracy of 42%.

CONCLUSION

There was no statistical significance between the presence of medial tenderness and deep deltoid ligament incompetence. There is a 25% chance of the fracture in question with medial tenderness having a positive external rotation stress and a 25% chance the fracture with no medial tenderness having a positive stress test. Medial tenderness in a Weber B lateral ankle fracture with a normal clear space on standard plain radiographs does not ensure the presence of a positive external rotation stress test.

Deltoid ligament injuries: diagnosis and management

The medial ligaments of the ankle are injured more often than generally believed. Complete deltoid ligament tears are occasionally seen in association with lateral malleolar fractures or bimalleolar fractures. Chronic deltoid ligament insufficiency can be seen in several conditions, including posterior tibial tendon disorder, trauma- and sports-related deltoid disruptions, and valgus talar tilting in patients who have a history of triple arthrodesis or total ankle arthroplasty. This article focuses on the anatomy and function of the medial ligaments of the ankle and establishes a rationale for the diagnosis and treatment of incompetent deltoid ligament.

The ability of the Lauge-Hansen classification to predict ligament injury and mechanism in ankle fractures: an MRI study

OBJECTIVES

The Lauge-Hansen classification system was designed to predict the mechanism and ligament injury patterns of ankle fractures on the basis of x-rays. The purpose of this study was to evaluate the accuracy of these predicted injury sequences using magnetic resonance imaging (MRI) in a series of patients with ankle fractures.

DESIGN

Retrospective cohort.

SETTING

Two university level 1 trauma centers.

PATIENTS

Fifty-nine patients with operative ankle fractures who were evaluated with both x-ray and MRI were included.

INTERVENTION

All patients had a standard 3-view ankle x-ray series before fracture reduction, followed by an MRI. All plain x-rays were assigned to a Lauge-Hansen category by an experienced orthopedic traumatologist. MRI studies were subsequently read by an MRI musculoskeletal radiologist for the integrity of the ankle ligaments.

MAIN OUTCOME MEASUREMENTS

After evaluation of the x-rays, fractures were classified according to the system of Lauge-Hansen, and the predicted presence, sequence, and mechanism of injury was determined. These were then compared to the actual injured structures on MRI in each case, and the ability of the Lauge-Hansen system to accurately predict the complete injury pattern was determined for the entire cohort.

RESULTS

Average patient age was 59 (range: 18 to 84) years. Of the 59 ankle fractures evaluated, 37 (63%) were classified as supination external rotation, 11 (19%) were pronation external rotation, 1 (2%) was supination adduction, and 10 (17%) were not classifiable on the basis of the Lauge-Hansen system. Of the 49 fractures that fit into Lauge-Hansen categories, 26 (53%) had patterns of ligamentous injury and fracture morphology that did not coincide with the Lauge-Hansen predictions. A common fracture pattern was observed in 8 of the 10 unclassifiable fractures, which included a high spiral fracture of the fibula, vertical shear fracture of the medial malleolus, posterior malleolar fracture, and complete tears of the anterior-inferior tibiofibular ligament and the interosseous membrane. In addition, over 65% of patients in this series had complete ligamentous injury and a fracture of the malleolus to which the ligament attaches.

CONCLUSIONS

These results demonstrate that the Lauge-Hansen classification system may have some limitations as a predictor of the mechanism of injury and the presence of soft-tissue damage associated with ankle fractures. The identification of a novel pattern of ankle fracture also illustrates how the system fails to describe all possible fracture patterns. For these reasons, we recommend that the Lauge-Hansen system be used only as a guide in the diagnosis and management of ankle fractures and not solely relied upon for treatment decisions. Although the exact clinical implications of the variety of ligamentous injuries observed on MRI are yet to be determined, this technique may be useful in individual cases in which doubt about joint stability and soft-tissue integrity exists. Additionally, MRI may be helpful in planning surgical approaches in atypical fractures in which injury patterns are less predictable solely on the basis of x-ray.

Ankle fractures

Although ankle injuries are common, it is imperative for the treating physician to be able to identify the mechanism of injury and accurately restore the normal anatomy of the ankle joint. Attention must be given to restoring the normal alignment and length of the fibula because of its dominant role in controlling talar stability. The medial ankle must not be overlooked, with the role of the deltoid taken into consideration. With a thorough understanding of the anatomy, biomechanics, mechanism of injury, and fixation techniques, repair of the damaged ankle joint can lead to rewarding outcomes for the patient and physician.

Radiographic indicators of ankle instability: changes with plantarflexion

BACKGROUND

The effect of plantarflexion on radiographic indicators of instability was investigated in matched pairs of stable ankles and unstable ankle fractures with complete deltoid ligament tears to test the hypothesis that differences exist in indicators as a function of either stability or position. The purpose of this study was to determine whether plantarflexion increases radiographic indicators of ankle fracture instability.

METHODS

Measurements from 34 patients scheduled for operative treatment of unstable ankle fractures were collected prospectively from normal, stable ankles and the injured, unstable ankles. Instability was defined as a positive fluoroscopic stress examination under anesthesia. Stability and instability and neutral position and plantarflexion were associated with eight radiographic indicators of which five were distances in millimeters and three were binomial (either stable or unstable).

RESULTS

Measurements were larger in the unstable ankles than in the normal stable ankles. Plantarflexion was associated with increased distances in stable ankles, and a trend was seen in unstable ankles. Plantarflexion was associated with increased binomial indicators in unstable ankles but not in stable ankles.

DISCUSSION

Joint positioning affected measurement of ankle stability: plantarflexion increased the sensitivity of radiographic indicators.

Stress radiographs after ankle fracture: the effect of ankle position and deltoid ligament status on medial clear space measurements

OBJECTIVE

This study was designed to determine 1) how ankle position affects the medial clear space by using stress radiographs, 2) which medial clear space measurement, overall width or increase in width, better predicts deep deltoid ligament disruption after Weber type-B distal fibular fracture, and 3) what value of medial clear space is most predictive of deep deltoid ligament disruption after Weber type-B distal fibular fracture.

DESIGN

Cadaveric fracture model.

SETTING

Biomechanics laboratory.

INTERVENTION

Fluoroscopic mortise views were taken of 6 fresh cadaveric ankles mounted in a fixture permitting both positioning in neutral flexion, dorsiflexion, and plantarflexion, and the application of internal and external rotational forces. After destabilizing the ankles according to the supination-external rotation mechanism of Lauge-Hansen, repeat radiographs were taken with the same combination of flexion and applied rotational stress.

MAIN OUTCOME MEASURE

Radiographic measurements of medial clear space width and changes in medial clear space were made.

RESULTS

A medial clear space of > or =5 mm on radiographs taken in dorsiflexion with an external rotational stress was most predictive of deep deltoid ligament transection after distal fibular fracture. In dorsiflexion-external rotation, medial clear spaces of > or =4 mm yielded lower specificity and positive predictive value, whereas > or =6 mm yielded lower sensitivity and negative predictive value. All other stress conditions and increases in medial clear space of 2 or 3 mm were less predictive.

CONCLUSIONS

Ankle stress radiographs taken in dorsiflexion-external rotation were most predictive of deep deltoid ligament disruption after distal fibular fracture. Under this stress condition, a medial clear space of > or =5 mm was the most reliable predictor of deep deltoid ligament status.

Intraoperative diagnosis of syndesmosis injuries in external rotation ankle fractures

OBJECTIVE

This study was designed to compare intraoperative fluoroscopic stress testing, static radiographs, and biomechanical criteria for the diagnosis of distal tibiofibular syndesmotic instability associated with external rotation type ankle fractures.

DESIGN

Prospective, consecutive series.

SETTING

Academic level 1 trauma center.

PATIENTS/PARTICIPANTS

Thirty-eight skeletally mature patients with unstable unilateral external rotation ankle fractures were prospectively recruited.

INTERVENTION

Before surgery, the treating surgeon detailed the operative treatment plan, including need for syndesmotic fixation. In pronation-external rotation injuries, biomechanical criteria were applied to predict syndesmotic instability. Ankles were examined using intraoperative fluoroscopic external rotation stress tests. The contralateral uninjured limb was used as a control. A 7.2-Nm force was applied for the external rotation stress examination. Stress testing was performed after lateral malleolar fixation and repeated after medial and syndesmotic fixation.

MAIN OUTCOME MEASURES

The incidence of syndesmotic instability was determined based on radiographic clear space measurements and compared with previously published criteria.

RESULTS

Intraoperative fluoroscopy detected unpredicted syndesmotic instability in 37% of ankles. In supination-external rotation (OTA 44B) injuries, unpredicted syndesmosis instability was found in 10 of 30 patients (33%). In pronation-external rotation injuries (OTA 44C), 4 of 7 patients (57%) were associated with syndesmosis disruption not predicted by biomechanical criteria. In bimalleolar fractures, syndesmosis fixation improved stability compared with rigid bimalleolar fixation alone (P < 0.01).

CONCLUSIONS

Preoperative radiographs and biomechanical criteria are unable to routinely predict the presence or absence of syndesmosis instability. Rigid bimalleolar fixation was frequently not sufficient to stabilize syndesmotic disruption. Intraoperative stress fluoroscopy is a valuable tool for detection of unstable syndesmotic injuries.

Stress examination of supination external rotation-type fibular fractures

BACKGROUND

Deltoid incompetence in association with an isolated fibular fracture is assumed to be present if there is medial tenderness, ecchymosis, or substantial swelling. We sought to determine whether these soft-tissue indicators predict deltoid incompetence by comparing such findings with the findings on stress radiographs.

METHODS

Over a thirty-two-month period, 138 patients who presented acutely with a Weber type-B supination-external rotation (SE) fibular fracture were evaluated for tenderness (in nine locations), ecchymosis, and swelling. Patients who presented with an apparently isolated fibular fracture and an intact ankle mortise (with a medial clear space of < or =4 mm and no talar subluxation) were evaluated with a stress radiograph to determine deltoid competence. Four groups of patients were identified: those who had an SE2 fracture (defined as those who had a stable ankle on the stress radiograph), those who had a stress (+) SE4 fracture (defined as those who had an unstable ankle on the stress radiograph), those who had an SE4 fracture (defined as those who presented with a wide medial clear space), and those who had a bimalleolar fracture. These four groups were compared with regard to tenderness, swelling, and ecchymosis at the time of initial presentation. Patients with SE2 injuries were allowed immediate weight-bearing.

RESULTS

Of the ninety-seven patients who presented with an isolated fibular fracture and an intact mortise, sixty-one had a stable SE2 injury and thirty-six had an unstable stress (+) SE4 injury. All stable SE2 injuries healed with an intact mortise. Medial tenderness, ecchymosis, and swelling were not predictive of deltoid incompetence (instability).

CONCLUSIONS

Stress radiographs allow for the accurate diagnosis of deltoid incompetence in patients with Weber type-B SE fibular fractures and no other osseous injury. Soft-tissue indicators are not accurate predictors of instability. If medial tenderness, ecchymosis, and swelling are used as operative indications, in some cases surgery may be performed on stable ankles.

Acute posttraumatic planovalgus foot deformity involving hindfoot ligamentous pathology

This article outlines the pathology of posttraumatic adult flat foot deformity that involves hindfoot ligamentous injury. The clinical presentation, radiographic findings, and pathology that are noted at the time of reconstruction are described. A proposed surgical reconstruction is presented that has successfully reconstructed the longitudinal arch of the affected foot.

Kinematic behavior of the ankle following malleolar fracture repair in a high-fidelity cadaver model

BACKGROUND

Previous studies involving axially loaded ankle cadaver specimens undergoing a passive range of motion after fracture have demonstrated rotatory instability patterns consisting of excessive external rotation during plantar flexion. The present study was designed to expand these studies by using a model in which ankle motion is controlled by physiologically accurate motor forces generated through phasic force-couples attached to the muscle-tendon units.

METHODS

Eight right unembalmed cadaver feet were tested in a dynamic gait simulator that reproduces the sagittal kinematics of the tibia while applying physiological muscle forces to the tendons of the major extrinsic muscles of the foot. Six-degrees-of-freedom kinematics of the tibia and talus were measured with use of a VICON motion-analysis system. The experimental conditions included all combinations of lateral and medial injury to reproduce the clinical classifications of ankle fracture. Statistical analysis was performed with repeated-measures analyses of variance.

RESULTS

The talus of the intact ankles demonstrated coupled external rotation and inversion relative to the tibia as the ankle plantar flexed. Osteotomy of the fibula, simulating a lateral ankle fracture, slightly but significantly increased external rotation and inversion of the talus (p < 0.001), whereas disruption of either the superficial or the deep deltoid ligament increased talar eversion (p < 0.003) and disruption of the deep deltoid ligament increased internal rotation (p < 0.0001). The aberrant motions were corrected by repair of the injured structure.

CONCLUSIONS

The predominant coupled rotation of the talus is external rotation associated with plantar flexion. Following progressive ankle destabilization, talar external rotation and inversion increased.

CLINICAL RELEVANCE

The clinical decision-making process regarding the treatment of ankle fractures centers on determination of whether the injury is expected to result in abnormal motion, which is thought to predispose to the development of arthritis. The present study demonstrated a remarkable degree of ankle stability during stance phase even when there was severe disruption of medial and lateral structures. This finding suggests that a main determinant of clinical outcome after ankle fracture may be ankle motion during swing phase, when ankle stability is not augmented by the combination of axial loading and active motor control of motion. If swing-phase motion is abnormal, then the ankle may be in a vulnerable position at the point of heel-strike.

Pitfalls in the treatment of fractures of the ankle and talus

Displaced fractures of the ankle are a common component of current orthopaedic practice, whereas displaced fractures of the talus are unusual. Ankle fractures generally are produced by indirectly applied, relatively low energy forces, whereas talus fractures are created by higher energy axial loading. Despite these inherent differences, the end result of either injury can be avascular necrosis, posttraumatic arthritis, or soft tissue loss. Complications and poor results can arise from the inherent characteristics of the injury, from failure to accomplish appropriate treatment objectives, from overzealous treatment goals, or from overlooking subtle clinical or radiographic signs. The goal of the current study is to provide a method of evaluating the characteristics of these injuries to optimize functional outcomes and avoid morbidity.