Treatment of mandibular-condylar fractures.
Particularly with true dislocation fractures, nonoperative treatment with maxillomandibular fixation followed by physiotherapeutic exercises leads to poor results, as was proved with axiography and clinical examinations. The main reason for this is the shortening and scarring of the condyloid process and the lack of function of the lateral pterygoid muscle. The condyle with its insertion of the muscle is usually displaced medially and anterially and nearly in touch with the origin on the pterygoid process so that protrusion by the muscle is no longer possible. The physiologic relationship of the lateral pterygoid muscle is restored after reduction of the condyle and osteosynthesis of the condylar neck fracture and the original distance between origin and insertion of the muscle is re-established and is a fundamental necessity for regaining function (Fig. 40). The anchor screw osteosynthesis is a most effective technique with low limitations for its indication. A comparison with plates shows this technique to be very economic because one anchor screw has the effect of at least one five-hole plate with five plating screws. That means a reduction of osteosynthesis implants of up to 80%, which saves a lot of money. On the other hand, the sophisticated technique of an anchor screw osteosynthesis needs some training on the part of the surgeon to get the best results possible. In general, we could realize that the anchor screw osteosynthesis gives a perfect adaptation of the fracture ends with compression also on the inner cortical layer, which with plates is only possible in rare cases. After an osteosynthesis of mandibular condyle neck fractures with an axial anchor-screw there are a few cases with an absorptive process in the fracture interface where the screw migrates in an axial direction with loosening of the osteosynthesis. This effect can be compared with the effect of a dynamic hip screw, which leads to compression of the callus, which speeds up bony union at the expense of shortening the bone. When the same absorption happens using a plate, the fracture ends cannot become sintered and the plate is in danger of fracturing as a result of metal fatigue. Ceipek evaluated 136 patients with mandibular condylar neck fractures treated with axial anchor screw osteosynthesis. Thirty-six of these screws showed signs of migration, but only 3.7% for more than 4 mm. For the migration process there are some important risk factors: difficult repositioning of the proximal fragment, dorsal luxation fracture, indirect method of anchor screw osteosynthesis, narrow condyle neck, no intercuspation in the molar region, no compliance, and disturbance of bone healing. Another stable technique of osteosynthesis should be used if patients show more risk than one risk factor.