Журнал «Травма» Том 15, №5, 2014

The use of polymeric devices is very common for internal fixation fractures recently [1, 2, 3]. Magnetic resonance imaging (MRI) and computed axial tomography (CAT) after polymeric osteosynthesis can provide us with additional information. The investigations reveal some peculiarities of clinical and radiological picture that are not properly described in literature. The presence of polymeric device doesn’t hamper visualization of the investigated area, allows to follow-up processes of fracture healing and remodeling. There is a necessity to develope a new approach to interpreting data of these investigations. Fixing devises made of polyamide-12 (P-12) have been designed at orthopedics, traumatology and neurosurgery department of Bukovinian state medical university and undergo clinical study since 1969 [4]. The set of designed fixing devises include screws, tension-bolts, cylindrical and conical pins, and arrow-shape devices.

The aim of the research. To determine clinical and rentgenological changes, peculiarities of CAT and MRI picture of bone segment after open reduction internal fixation (ORIF) with polymeric fixing device in long-term outcome.

Materials and methods. Clinical-rentgenological study shows results of treatment 62 patients after internal fixation of metaepiphysial and oblique diaphysial fractures with a follow-up from 21 to 44 years with fixation devices made of P-12. Osteosyntesis fractures of upper extremities was made in 29 patients with fractures of upper extremities (46,8 %), lower extremities operated in 33 patients (53,2 %). The results of treatment was follow up at 61 patients within 10 years, 48 patients – within 25 years, 18 patients – up to 40 years, and 41–44 years at 3 patients. ORIF fractures neck of humerus was performed with arrow-shaped devices. Screws made of P-12 were used for internal fixation fractures of olecranum, humeral, femoral and tibial condyles, and fractures of talus after reduction of its dislocation. Tension bolts were used for internal fixation oblique and spiral shaft fractures of tibia. Small devices, like conical pins, were used in operative treatment of maleolus fractures. 

Patients undergo common rentgenological investigations of injured bone segment in two routine views when they were admitted and the same day when surgery was performed.  Later patients were examined in 1, 3, 6, 12 months after operative treatment, and far outcome in 5, 10, 20, 30, 40 and more years were studied with use of CAT and MRI investigations of injured and non-injured extremities.

Far results of treatment were considered as good, satisfactory and unsatisfactory, according to the valid standards of evaluation quality of treatment injuries of locomotor-system (a decree  # 41 from 30.03.94 “About regulation orthopedo-traumatological service in Ukraine”). To objectify quantitative values of clinical trial they were transformed into score system. Unsatisfactory result was appreciated as 0 points, satisfactory – 1 point, good – 2 points. To estimate results of research such clinical criterions were used: pain in the site of healed fracture, restriction of movement, function of extremity, presence of deformity or shortening of the segment, muscle strength, presence of neuro-dystrophic changes. Radiological criterions at the site of P-12 implantation were: presence of pathologically changed regions, aggravation of osteoarthritis of adjacent joints, changes of bone tissue density and structure.

Results and discussions.  Clinical examination patients in far postoperative period reveals that general condition patients was satisfactory, complains on pain at injured segment were absent. The axis of the extremity is correct; range of motion in joints is not restricted. There is a whitish, smooth, movable scar at the site of operation and induration at the place of polymeric device outlet, but local inflammation, pain or other unpleasant sensations as usual were absent.  X-ray examination of healed diaphysial fractures of tibia after internal fixation with polymeric devices shows restoration of the intramedullary canal, cortical layer is thickened, sharp. The peculiarity of X-ray picture during the whole period of observation is the presence of canal as the radiolucent area, indicating the location of polymeric implant. It is surrounded by dense strip. The head of the bolt and tension nut are also surrounded with dense bone tissue.

X-ray examination of bone segments after intraarticular and periarticular fractures shows bone tissue remodeling with restoration of sharp trabecular structure and some periosteal bone deposition in sites of screw insertion. There were found age-related degenerative-dystrophic changes in surrounding joints, but they were symmetrical for both extremities and, on our opinion, were not related with previous injury. Radiological picture is changing very slowly within years and decades. We revealed some decreasing of screw diameter and thickening capsule around polymeric screw, which we associate with possible decreasing of screws weight within 30–44 years of implantation in human organism.   

CAT areas of healed fractures in metaepiphysis shows regular cancelous structure with bone density equal to the other extremity. In diaphysial areas normal anatomy is restored, intramedullary canal is present. Polymeric device is present as compact homogeneous mass with average density 121,84 ± 22,8 HU (Haunsfield units) in tibia and 132,4 ± 25,8 HU in ankle joint.

MRI investigation shows the polymeric device, as area of low signal intensity, which is surrounded with 1-2 mm width hypointensity zone that is proceeding into unimodal bone structure. At dyaphysial healed fractures we found normal intramedullar canal proximal and distal from place of polymeric device implantation. There were no pathological changes in bone and soft tissues found. Local edema and inflammation of bone and soft tissue are absent. The investigation of elbow, knee, ankle joints reveal the congruent surfaces, the structure of cartilage is not changed, signs of inflammation in the joints and surrounding tissues were not found. The investigation of implantation area in STIR mode didn`t show any subcartilaginous or bone tissue edema, thickening of joint capsule and excessive fluid.

Polymeric devices made of P-12 provide stable fixation fracture fragments within the process of healing, but they stay in organism for a long time. Local and general side effects were not found. Using polymeric fixation devices was yielded 83,9 % (52 patients) of good and 11,3 % satisfactory results after internal fracture fixation with P-12 within 5 years; 87,7 % of good, and 10,5 % of satisfactory results within 6-10 years. Further outcome shows some worsening of results due to degenerative-dystrophic age-related changes in the joints but those were symmetrical. The outcome within 11–30 years revealed good results in 24 patients (77,4 %), satisfactory – in 7, within 30-40 years good results were found in 61,1 % (11 patients), satisfactory – in 27,8 % (5 patients); and two patients have good and one – satisfactory result within 21–44 years.

Conclusions. The clinical, roentgenlogical, CAT, MRI investigations of bone segments after ORIF with P-12 did not found pathological changes of bone tissue within long term outcome – up to 44 years. Within such long period the diameter of P-12 fixing device is decreased per ¼, that indicates on it’s possible slow destruction. Cites of screw insertion are covered with bone tissue which has density similar to cortical bone. Resorption of bone tissue and local osteoporosis around P-12 devices are absent. There were no needs to remove polymeric devices. Thus, the presence of P-12 polymeric device doesn’t cause local or general negative effect within its long period implantation.