The Effect And Evaluation Of Absorbable Screws And Cortical Bone Screws On Distal Tibiofibular Syndesmosis Injury

Objectives:To compare the effect of internal fixation on distal tibiofibular syndesmosis injury, using absorbable screws and cortical screws respectively, and provide a theoretical basis for the choice of internal fixation in tibiofibular syndesmosis injury. Methods:1.49cases of distal tibiofibular syndesmosis injury in orthopedic department from January2008to June2011were selected. The patients were divided into two groups.23patients used absorbable screws for fixation (group A). Patients in other26cases used cortical bone screws for fixation (group B);2. Patients in group A, using absorbable screws for fixation, consisted of16males and7females with an average age of33years (range,16to65). They were classified into supination external rotation type (16cases), pronation and abduction type (2cases) and pronation external rotation type (5cases) according to Lange-Hansen classification. When fixing with absorbable screws, patients in18cases were fixed with three layers of cortical screws and5fixed with four layers of cortical screws;3. Patients in group B, using cortical bone screws for fixation, consisted of17males and9females with an average age of35years (range,18to68years). They were divided into supination external rotation type (15cases), pronation and abduction type (3cases) and pronation external rotation type (8cases) according to Lange-Hansen classification. When fixing with cortical bone screws, patients in21cases were fixed with three layers of cortical screws and5fixed with four layers of cortical screws.4. Observe and compare the following factors including the postoperative skin healing, and, by reviewing of X-rays regularly, the tibiofibular syndesmosis reduction, the healing of fracture, screw loosening or breakage, and osteolysis absorption. Then, score the functional activities of patients using the Ankle and Hind Foot Score System giving by American Orthopaedic Foot and Ankle Society;5. The therapeutic outcome was observed and thus measured by AOFAS ankle function evaluation The postoperative ankle and hind foot score of two groups were evaluated by T test and the effect of three or four layers of fixation were evaluated by rank sum test. Results:1.All the patients were followed up for6to15months (mean11.4months);2. The hospitalized time in group A was9to55days with an average of18.3days. The X-rays after surgery showed normal ankle hole. In23cases, incision healing was in stage I expect for one case of pain, erythema, which disappeared three weeks later without significant sinus formation. None of the tibiofibular syndesmotic joint width increased after the patients began their gradual weight-bearing practice10to12weeks later. Among the23cases, the Ankle and hind foot score showed an excellent result in four, a good result in fourteen, fair in four and poor in one. The hospitalized time in group B was10to67days with an average of17.5days. The X-rays image after surgery showed normal ankle hole. In all the26cases, incision healing were in stage I no infection occurred.17patients of the total26cases began their gradual weight-bearing practice10to12weeks after operation when the screws removed. In other9cases, patients did not have the inferior tibiofibular screws removed for personal reasons. There was one case of screw breakage with the gradual weight-bearing practice10to12weeks after operation. In six cases, visible translucent area could be seen around screws. None of the tibiofibular syndesmotic joint width increased. The Ankle and Hind Foot Score showed an excellent result in four, good in seventeen, fair in three and poor in two. During the follow-up period, all fractures healed within3to6months. Neither the difference found in postoperative ankle and hind foot scoring system(P>0.05) nor the difference found in the comparison between the curative effect of three and four layers of fixation (P>0.05)was statistically significant. Conclusions:1.The clinical efficacy of absorbable screws on distal tibiofibular syndesmosis injury is similar to that of cortical screws fixation;2.When dealing with tibiofibular joint separation, the absorbable screw fixation is preferable;3. No significant difference is found between the effect of three layers of cortical fixation and four.4. The absorbable screw may have some advantages including more biocompatible, no significant stimulation of the organization and no need of removal. It can exempt the pain in the secondary surgery and reduce the economic burden of patients, therefore, be worthy of clinical application.