Harri Pakarinen

RhBMP-7 accelerates the healing in distal tibial fractures treated by external fixation

External fixation of distal tibial fractures is often associated with delayed union. We have investigated whether union can be enhanced by using recombinant bone morphogenetic protein-7 (rhBMP-7). Osteoinduction with rhBMP-7 and bovine collagen was used in 20 patients with distal tibial fractures which had been treated by external fixation (BMP group). Healing of the fracture was compared with that of 20 matched patients in whom treatment was similar except that rhBMP-7 was not used. Significantly more fractures had healed by 16 (p=0.039) and 20 weeks (p=0.022) in the BMP group compared with the matched group. The mean time to union (p=0.002), the duration of absence from work (p=0.018) and the time for which external fixation was required (p=0.037) were significantly shorter in the BMP group than in the matched group. Secondary intervention due to delayed healing was required in two patients in the BMP group and seven in the matched group. RhBMP-7 can enhance the union of distal tibial fractures treated by external 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.

Syndesmotic Fixation in Supination-External Rotation Ankle Fractures A Prospective Randomized Study

Background: This study compared mid-term functional and radiologic results of syndesmotic transfixation with no fixation in supination external rotation (SER) ankle fractures with intraoperatively confirmed syndesmosis disruption. Our hypothesis was that early-stage good functional results would remain and unfixed syndesmosis disruption in SER IV ankle fractures would not lead to an increased incidence of osteoarthritis. Methods: A prospective study of 140 operatively treated patients with Lauge-Hansen SER IV (Weber B) ankle fractures was performed. After bony fixation, the 7.5-Nm standardized external rotation 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. The patients were randomized to either syndesmotic screw fixation (13 patients) or no syndesmotic fixation (11 patients). After a minimum of 4 years of follow-up (mean, 58 months), ankle function and pain (Olerud-Molander, a 100-mm visual analogue scale [VAS] for ankle function and pain) and quality of life (RAND-36) of all 24 patients were assessed. Ankle joint congruity and osteoarthritis were assessed using mortise and lateral projection plain weight-bearing radiographs and magnetic resonance imaging (MRI; 3T) scans. Results: Improvement in Olerud-Molander score, VAS, and RAND-36 showed no significant difference between groups during the follow-up. In the syndesmotic transfixation group, improvements in all functional parameters and pain measurements were not significant, whereas in the group without syndesmotic fixation, the Olerud-Molander score improved from 84 to 93 (P = .007) and the pain (VAS) score improved from 11 to 4 (P = .038) from 1 year to last follow-up. X-ray or MRI imaging showed no difference between groups at the last follow-up visit. Conclusion: With the numbers available, no significant difference in functional outcome or radiologic findings could be detected between syndesmosis transfixation and no-fixation patients with SER IV ankle fracture after a minimum of 4 years of follow-up. Level of Evidence: Level II, prospective comparative study.

Posterior translation of the fibula may indicate malreduction: CT study of normal variation in uninjured ankles.

Objectives: The aim of our study was to assess the intersubject and intrasubject variations of distal tibiofibular syndesmosis on computed tomography (CT) scans and to define standardized measures to verify syndesmosis reduction. Design: A retrospective study of 107 CT scans of ankles with normal tibiofibular syndesmosis. Setting: Main trauma center, university teaching hospital. Patients: The CT scans of 64 patients were reviewed by 2 musculoskeletal radiologists. Main Outcome Measurements: Bilateral variation was estimated. The intra- and interobserver reliabilities were calculated using standardized measurement points. CT measurements included the length of the tibial incisura (LI), A width and P width of the incisura (PW), depth of the incisura, narrowest part of the incisura, and sagittal translation of the fibula. Results: In 97% of normal cases, the fibula is situated either centrally or anteriorly in the tibial incisura. There were significant differences in PW and LI between genders, and the difference between the PW and A width was significantly larger in males (2.7 mm, SD 2.1) than in females (1.9 mm, SD 1.6, P = 0.023, t test). Significant asymmetry was not detected between ankles in single subjects. All CT measurements demonstrated good inter- and intraobserver reliabilities. Conclusions: If P translation of the fibula is present, malreduction should be considered. Sagittal translation measurements are not affected by the size of the joint or the gender of the patient, in contrast to traditionally used cross-sectional measurement methods.

Stability Criteria for Nonoperative Ankle Fracture Management

Background: This study was designed to see if stability based criteria are useful in choosing between nonoperative and operative treatment of ankle fractures. Materials and Methods: One hundred sixty ankle fractures in skeletally mature patients were retrospectively analyzed to obtain an epidemiological profile in a population of about 130,000. One hundred thirty patients had followup of more than 2 years. A decision between operative and nonoperative treatment was made by the surgeon-on-duty, based on accepted stability criteria. Fractures were classified according to Weber and Lauge-Hansen systems. Clinical outcome was assessed using the scoring systems of Olerud-Molander, the RAND 36-Item Health Survey and the Visual Analogue Scale (VAS), measuring pain and function. Results: The overall incidence of ankle fractures was 154/100,000. Nonoperatively treated patients had more displacement of the distal fibula after treatment, but less pain and better Olerud-Molander (good or excellent, 89% vs. 71%) and VAS functional scores. Independent factors for worse outcome were female gender, older age, unstable fracture and co-morbidity. No nonoperatively treated patients needed operative fixation during followup. Conclusion: Stability-based fracture classification was a simple and useful tool in decision-making for the treatment of ankle fractures. We found lateral malleolar fractures could be treated nonoperatively with success if the ankle mortise was stable. Displacement of the distal fibula after treatment did not affect functional scores or pain. Level of Evidence: III, Comparative Case Series

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.

Rotational Dynamics of the Normal Distal Tibiofibular Joint With Weight-Bearing Computed Tomography

Background: The normal distal tibiofibular joint is strongly stabilized by the syndesmosis, where previous cadaveric, biomechanical studies demonstrated only minimal widening and posterior translation of the fibula in external rotation of the ankle. However, little is known about normal rotational dynamics of the distal tibiofibular joint in upright weight-bearing conditions. The purpose of this study was to investigate the normal anatomy and rotational dynamics of the distal tibiofibular joint under physiological conditions on weight-bearing cone beam computed tomography (WBCT). Methods: In a cross-sectional study of 32 subjects, low-dose WBCT scans of uninjured bilateral ankles were performed. Normal intersubject and intrasubject variation in neutral position and changes in maximal internal and external rotation of the ankle were studied. Sagittal translation of the fibula, anterior and posterior widths of the distal tibiofibular syndesmosis, tibiofibular clear space (TFCS), and rotation of the fibula were measured. Results: In the neutrally loaded ankle, the fibula was located anteriorly in the tibial incisura in 88% of the subjects. When the ankle was rotated, mean anteroposterior motion was 1.5 mm and mean rotation of the fibula was 3 degrees. There was no significant change in TFCS between internal and external rotation. Large intersubject variation was detected, but intrasubject variation between ankles was less than 1 mm and 1 degree. Conclusions: This study provides reference values to evaluate the dynamics of the normal distal tibiofibular joint. The internal control of the contralateral ankle seemed to be a better reference than the population-based normal values. Clinical Relevance: The current study provides the reference values to evaluate the rotational dynamics of a normal distal tibiofibular joint.

Stability assessment of the ankle mortise in supination-external rotation-type ankle fractures: lack of additional diagnostic value of MRI.

BACKGROUND This prospective diagnostic study assessed the utility of MRI (magnetic resonance imaging) findings for the deep aspect of the deltoid ligament in evaluating the stability of the ankle mortise in patients who have an SER (supination-external rotation)-type lateral malleolar fracture with no widening of the medial clear space. METHODS Sixty-one patients with a unilateral lateral malleolar fracture resulting from an SER mechanism were enrolled. Two surgeons assessed the stability of the ankle mortise with use of an external-rotation stress test. The anterior and posterior parts of the deep deltoid ligament were investigated with 3.0-T MRI and were graded (as normal, edematous, partial tear, or complete tear) by two musculoskeletal radiologists. The medial clear space was measured and compared with the MRI findings for the deep deltoid ligament in stable and unstable injuries. Interobserver reliability was calculated for both external-rotation stress testing and MRI assessment. RESULTS Thirty-three patients had a medial clear space of ≥ 5 mm in the external-rotation stress test. According to MRI, all of these patients had an injury involving the deep deltoid ligament (an edematous ligament in five, a partial tear in twenty-six, and a total tear in two). Twenty-eight patients had a medial clear space of <5 mm, and MRI indicated a deep deltoid ligament injury in all of these patients as well (an edematous ligament in nine and a partial tear in nineteen). The medial clear space increased according to the severity of the deep deltoid ligament injury as indicated by MRI (p < 0.001). The interobserver agreement of the external-rotation stress test was excellent (94% agreement; kappa = 0.87), whereas the interobserver reliability of the MRI assessments by the two musculoskeletal radiologists was fair to moderate (72% agreement for the posterior part of the deep deltoid ligament and 56% for the anterior part; kappa = 0.46 and 0.22, respectively). CONCLUSIONS On the basis of the study results, we do not recommend the use of MRI when choosing between operative and nonoperative treatment of an SER-type ankle fracture.

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.

Rotational Dynamics of the Talus in a Normal Tibiotalar Joint as Shown by Weight-Bearing Computed Tomography.

BACKGROUND The aim of this study was to investigate the normal anatomy and rotational dynamics of the talus in the tibiotalar joint using weight-bearing cone-beam computed tomography (WBCT). METHODS In a cross-sectional study of thirty-two healthy subjects divided into two age groups (twenty-six to thirty-six years of age and sixty to sixty-four years of age), low-dose WBCT scans of both uninjured ankles were obtained. The rotation of the talus, medial clear space, anterior and posterior widths of the tibiotalar joint, translation of the talus, and talar tilt were measured. The primary outcome measures were intersubject and intrasubject (bilateral) variation of the talar movements between maximal internal and external rotation. The secondary outcome measures were the effect of sex and age on the movements of the talus. RESULTS When the ankle is rotated, the talus rotates a mean of 10° with no substantial widening of the medial clear space. All of the measured values changed subtly but statistically significantly between maximal internal and maximal external rotation, with mean changes of 10° (standard deviation [SD] = 5.8°) in talar rotation (p = 0.006), 2.0° (SD = 1.5°) in talar tilt (p = 0.0015), -0.2 mm (SD = 0.5 mm) in the medial clear space (p = 0.01), 0.9 mm (SD = 0.8 mm) in the anterior width of the tibiotalar joint (p = 0.003), -0.4 mm (SD = 0.9 mm) in the posterior width of the tibiotalar joint (p = 0.011), and 2.9 mm (SD = 2.2 mm) in translation of the talus (p = 0.002). Intersubject variation was large, but there was very little intrasubject variation in the total rotational range of motion. There were no differences between men and women with regard to any of the measurements. CONCLUSIONS This study provides reference values with which to evaluate the dynamics of the normal tibiotalar joint in order to clarify rotational stability of the ankle mortise. The internal control of the contralateral ankle seems to be a better reference than population-based normal values.