Direct versus indirect posterior malleolar fixation in the treatment of trimalleolar ankle fractures: Is there a difference in outcomes?

Purpose: The purpose of this study was to examine the differences in functional outcomes between direct and indirect surgical fixation methods of the posterior malleolus in the setting of trimalleolar fractures and identify any variables affecting patient outcomes. Methods: Primary outcomes were evaluated by PROMIS scores for short-term outcomes regarding total pain (TP) and total function (TF) comparing 40 patients with direct fixation with 77 with indirect fixation. Continuous variables were analyzed using t tests for parametric variables and the Mann-Whitney U test for nonparametric variables. Categorical variables were analyzed using a χ2 test. Univariate and multivariate linear regression models were performed to analyze factors that affect outcomes of TP and TF. Results: There was no difference in TP or TF between groups (P = 0.65 vs. P = 0.19). On univariate linear regression for TP, BMI, incidence of complication, tobacco use, and open injury showed significance in increasing pain levels with open injuries providing the greatest effect (coef = 11.8). On multivariate analysis, BMI, incidence of complication, open injury, and tourniquet time all significantly increased pain. For TF, univariate analysis showed age, BMI, incidence of complication, and diabetes to decrease function, and use of external fixator and tourniquet time increased function. In the multivariate model, increased BMI, open injuries, and increasing tourniquet time all decreased TF while use of an external fixator increased TF. Conclusion: This study showed no difference in TP and TF using the PROMIS outcome scores when comparing direct fixation versus indirect fixation under univariate and multivariate models. Level of Evidence: Therapeutic III.

Leave it or fix it? How fixation of a small posterior malleolar fragment neutralizes rotational forces in trimalleolar fractures.

INTRODUCTION: This study investigated the effects of a small posterior malleolar fragment (PMF), containing less than 25% articular surface area, on ankle joint stability via computed tomography (CT) scanning under full weight bearing in a human cadaveric ankle fracture model. MATERIALS AND METHODS: A trimalleolar fracture with a PMF of less than 25% articular surface area was created in 6 pairs of fresh-frozen human cadaveric lower legs. The specimens were randomized into 2 groups stabilized by internal fixation including a positioning screw for syndesmotic reconstruction. In Group I the PMF was addressed by direct screw osteosynthesis, whereas in Group II the fragment was not fixed. Six predefined distances within the ankle were measured under axial loading. CT scans of each specimen were performed in intact and fixated states in neutral position, dorsiflexion and plantar-flexion of the ankle. RESULTS: In plantar-flexion, significant differences were detected between the groups with regard to rotational instability. Group II demonstrated a significantly increased inward rotation of the fibula compared with Group I. No significant differences were detected between the groups for each one of the measured distances in any of the three foot positions. CONCLUSIONS: Additional reduction and fixation of a small PMF seems to neutralize rotational forces in the ankle more effectively than a sole syndesmotic screw. Clinically, this becomes relevant in certain phases of the gait cycle. Direct screw osteosynthesis of a small PMF stabilizes the ankle more effectively than a positioning screw.

Clinical and radiological mid- to long-term results after direct fixation of posterior malleolar fractures through a posterolateral approach.

BACKGROUND: Direct fixation of posterior malleolar fractures has been shown to lead to higher accuracy of fracture reduction compared to an indirect anterior to posterior fixation but lacks long-term clinical results. This study shows the mid- to long-term clinical and radiological outcome after direct fixation of the posterior malleolus through a posterolateral approach. MATERIALS AND METHODS: Thirty-six patients with an ankle fracture including a posterior malleolar fragment (23 × AO-44C, 12 × AO-44B, 1 × unclassifiable) treated with direct fixation of the fragment through a posterolateral approach were retrospectively evaluated. There were 24 females (67%) with a mean age of 63 (range 34-80) years and a BMI of 28 (range 19-41) kg/m2 at the time of surgery. An initial fracture-dislocation was seen in 67%. The clinical outcome was assessed with the Visual Analog Scale (VAS, 0-10 points) and the American Foot and Ankle Society (AOFAS, 0-100 points) score. Posttraumatic osteoarthritis was recorded with the Van Dijk Classification (grade 0-III). Subgroup analyses of patient- and fracture-associated risk factors (age, BMI, smoking, fracture-dislocation, postoperative articular step-off) were assessed to reveal possible negative prognostic predictors. RESULTS: After a mean follow-up of 7.9 (range 3-12) years, the median VAS was 1 (IQR 0-2) point, and the median AOFAS score was 96 (IQR 88-100) points. Ankle range of motion measurements showed a significant, but clinically irrelevant, difference in plantar- and dorsiflexion between the affected and unaffected ankle. 92% of the patients were very satisfied or satisfied with the postoperative course. 89% had no preoperative signs of ankle osteoarthritis. Osteoarthritis progression was seen in 72%, with 50% showing grade II or III osteoarthritis at the final follow-up. No significant negative prognostic factors for a worse clinical outcome could be detected. CONCLUSION: Direct fixation of posterior malleolar fractures through a posterolateral approach showed good clinical mid- to long-term results with a high satisfaction rate but substantial development of posttraumatic ankle osteoarthritis. Further studies should include CT analysis of the preoperative fracture morphology and even, perhaps, the postoperative reduction accuracy to evaluate the benefit of posterior malleolar fracture reduction in preventing ankle osteoarthritis in the long term. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for authors for a complete description of levels of evidence.

Morphological characteristics of the posterior malleolar fragment according to ankle fracture patterns: a computed tomography-based study.

BACKGROUND: The posterior malleolar fragment (PMF) of an ankle fracture can have various shapes depending on the injury mechanism. The purpose of this study was to evaluate the morphological characteristics of the PMF according to the ankle fracture pattern described in the Lauge-Hansen classification by using computed tomography (CT) images. METHODS: We retrospectively analyzed CT data of 107 patients (107 ankles) who underwent surgery for trimalleolar fracture from January 2012 to December 2014. The patients were divided into two groups: 76 ankles in the supination-external rotation (SER) stage IV group and 31 ankles in the pronation-external rotation (PER) stage IV group. The PMF type of the two groups was assessed using the Haraguchi and Jan Bartonicek classification. The cross angle (α), fragment length ratio (FLR), fragment area ratio (FAR), sagittal angle (θ), and fragment height (FH) were measured to assess the morphological characteristics of the PMF. RESULTS: The PMF in the SER group mainly had a posterolateral shape, whereas that in the PER group mainly had a posteromedial two-part shape or a large posterolateral triangular shape (P = 0.02). The average cross angle was not significantly different between the two groups (SER group = 19.4°, PER group = 17.6°). The mean FLR and FH were significantly larger in the PER group than in the SER group (P = 0.024, P = 0.006). The mean fragment sagittal angle in the PER group was significantly smaller than that in the SER group (P = 0.017). CONCLUSIONS: With regard to the articular involvement, volume, and vertical nature, the SER-type fracture tends to have a smaller fragment due to the rotational force, whereas the PER-type fracture tends to have a larger fragment due to the combination of rotational and axial forces.

The role of a small posterior malleolar fragment in trimalleolar fractures: a biomechanical study.

AIMS: The aim of this study was to investigate the effect of a posterior malleolar fragment (PMF), with < 25% ankle joint surface, on pressure distribution and joint-stability. There is still little scientific evidence available to advise on the size of PMF, which is essential to provide treatment. To date, studies show inconsistent results and recommendations for surgical treatment date from 1940. MATERIALS AND METHODS: A total of 12 cadaveric ankles were assigned to two study groups. A trimalleolar fracture was created, followed by open reduction and internal fixation. PMF was fixed in Group I, but not in Group II. Intra-articular pressure was measured and cyclic loading was performed. RESULTS: Contact area decreased following each fracture, while anatomical fixation restored it nearly to its intact level. Contact pressure decreased significantly with fixation of the PMF. In plantarflexion, the centre of force shifted significantly posteriorly in Group II and anteriorly in Group I. Load to failure testing showed no difference between the groups. CONCLUSION: Surgical reduction of a small PMF with less than 25% ankle joint surface improves pressure distribution but does not affect ankle joint stability. Cite this article: Bone Joint J 2018;100-B:95-100.

Value of Early Postoperative Computed Tomography Assessment in Ankle Fractures Defining Joint Congruity and Criticizing the Need for Early Revision Surgery.

Previous investigators have questioned the reliability of plain radiographs in assessing the accuracy of ankle fracture reduction when these were compared with the computed tomography (CT) evaluation in the preoperative setting, in particular, in fractures with syndesmosis injuries or trimalleolar fragments. The role of CT assessment, however, has not been investigated in the early postoperative setting. In the early postoperative setting, reduction still relies most commonly on fluoroscopy and plain radiographs alone. In the present study, we hypothesized that early postoperative CT assessment of ankle fractures with syndesmosic injuries and posterior malleolar fragments can add valuable information about the joint congruity compared with plain radiographs alone and that this information could affect the decisions regarding the need for early revision surgery. A total of 352 consecutive operated ankle fractures were reviewed. Of these, 68 (19%) underwent early postoperative CT assessment and were studied further to identify the causes that prompted revision surgery. Of the 68 cases, despite acceptable reduction found on the plain radiographs, 20 (29%) underwent early (within 1 week) revision surgery after studying the CT scans, which revealed malreduction of the syndesmosis, malreduction of the posterior lip fragment, and intra-articular fragments. We concluded that in ankle fractures involving disruptions of the syndesmosis or posterior malleolar fragments, early postoperative CT assessment could be justified, because it will reveal malreduction and prompt early revision intervention for a substantial proportion of these patients.

Two-Year Follow-up Results of Anteroposterior Cannulated Screw Fixation of Posterior Malleolar Fragment in the Trimalleolar Fracture / 대한족부족관절학회지

PURPOSE: The purpose of this study was to assess the 2-year follow-up results of patients with a trimalleolar fracture, who had undergone an anterior incision cannulated screw fixation of the posterior malleolar fragment, which had more than 25% of articular involvement or had no cortical continuity with the distal tibia. MATERIALS AND METHODS: Among 28 patients with a trimalleolar fracture who had undergone fixation of the posterior malleolar fragment between February 2005 and February 2010, 14 patients, who underwent an anterior incision cannulated screw fixation of posterior malleolar fragment and were followed-up for more than 2 years, were selected. The postoperative clinical and radiological findings immediately and at the 1- and 2-year follow-up were compared. The clinical findings were evaluated as American Orthopaedic Foot and Ankle Society (AOFAS) score. The radiological assessment was evaluated as the maintenance of reduction, period to bone union, and the presence of nonunion, malunion, and complications. RESULTS: The clinical outcome by mean AOFAS score revealed 83.0 points in the group with preoperative displacement below 2 mm and 80.7 points in the group with preoperative displacement above 2 mm postoperatively. The mean AOFAS score was 91.7 and 93.1 points in the group with preoperative displacement below 2 mm on 1- and 2-year follow-up, respectively, and 89.8 and 91.7 points in group with the preoperative displacement above 2 mm on 1- and 2-year follow-up, respectively. After a 2-year follow-up among 14 cases selected for this study, 13 cases showed an excellent reduction state and only 1 case (7.1%) showed a displacement of more than 2 mm. No complication were encountered in the group with preoperative displacement below 2 mm. On the other hand, among 8 patients in the group with preoperative displacement above 2 mm, there were 3 with limitations of the range of motion of the ankle joint (37.5%) and 1 post-traumatic arthritis (12.5%) at the 2-year follow-up. CONCLUSION: Anterior incision cannulated screw fixation of the posterior malleolar fragment could be a valuable method for the treatment of trimalleolar fractures that provides satisfactory results.

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).

Treatment of the Trimalleolar Fracture Using Posterolateral Approach: Minimum 2-year Follow Up Results

PURPOSE: To analyze the long term follow up results of treatment with posterolateral approach and to investigate its usefulness in the patients of trimalleolar fracture with posterior fragment which is above 25% of articular involvement. MATERIALS AND METHODS: There were 34 cases of trimalleolar fracture in our hospital from May 2004 to April 2008. We investigated 20 patients who underwent operation with the posterolateral approach and over-2 years follow up cases. The mean follow up period was 34 (24~58) months. Preoperative posterior malleolar fragment involved above 25% of articular surface in all cases and displaced more than 2 mm in 11 cases. We analyzed the radiologic type of posterior malleolar fragments and evaluated the function and pain through AOFAS score and complications. RESULTS: All cases showed primary union at mean 13.1 weeks. The complications are that partial ankylosis result of soft tissue contracture is seen in 2 cases (10%) and post-traumatic arthritis is seen in 1 cases (5%) and 17 cases (85%) of all patients are showed excellent AOFAS score. CONCLUSION: The posterolateral approach is a valuable method because that it enables us to easily reduction and internal fixation of the posterior malleolus and lateral malleolus at one time and the results are satisfied for a long time follow up.

Treatment of the Posterior Malleolar Fragment of Trimalleolar Fracture Using Posterolateral Approach: Preliminary Report / 대한정형외과학회잡지

PURPOSE: We wanted to evaluate the effectiveness of posterolateral approach for open reduction and internal fixation of posterior malleolar fragment with trimalleolar fracture of ankle joint. MATERIALS AND METHODS: There were 27 cases of trimalleolar fracture in our hospital from Jan. 2005 to Dec. 2007. We investigated 10 patients who underwent operation with the posterolateral approach. The mean follow up period was 20 (6-36) months. Preoperative posterior malleolar fragment involved above 25% of articular surface in 10 cases and displaced more than 2 mm in 4 cases. We analyzed the radiologic type of posterior malleolar fragments and complications, and evaluated the AOFAS score. RESULTS: All cases showed primary union mean 11.8 (8-14) weeks. The complication focal skin necrosis in one case and all patients showed excellent AOFAS score. CONCLUSION: The posterolateral approach may be a useful for open reduction and internal fixation of posterior malleolar fragment with trimalleolar fracture, especially simultaneous management of lateral malleolar fracture.

Irreducible Ankle Fractures by Locked Posterior Malleolar Fragment: Case Report / 대한족부족관절학회지

Irreducible fracture dislocation of the ankle associated with comminuted displaced fracture of posterior malleolus is rare. Locked posterior malleolar fragments interfere with reduction of fibula or talus in ankle fractures. Prompt recognition and appropriate surgical approaches are necessary to achieve anatomical reduction of the ankle fractures.