ABSTRACT
Objective To test the mechanical properties of a self-developed novel anterior mid-distal humerus anatomic locking plate (hereinafter referred to as the new plate) and to improve its design to provide theoretical support for its clinical application. Methods Twenty intact humerus from embalmed human cadavers were obtained and used for the biomechanical test on mid-distal humeral shaft fracture models by using the new plate (group A) and 4.5 mm LC DCP（limited contact dynamic compression plate）(group B), respectively. Both groups were compared under axial compression, medial-lateral bending, medial-lateral three-point bending and external rotation torque. Results The stiffness, strength and stress shielding of the new plate for mid-distal humeral shaft fractures under four different loads were superior to those of 4.5 mm LC-DCP, and the differences were statistically significant(P<0.05). Conclusions The new plate can satisfy the requirements of physical training at early stage for fixed mid-distal humeral shaft fractures, which gives great clinical values.
ABSTRACT
Objective To compare proximal femoral nail(PFN)introduction by percutaneous K-wire through a small incision with conventional PFN introduction protocol in the treatment of intertrochanteric fractures. Methods From January 2004 to March 2005,51 patients with intertrochanteric fractures were randomly dis- tributed into a minimally invasive treatment group(group MI)and a conventional treatment group(group C).All the fractures were closely reduced.In group MI a K-wire was percutaneously inserted through the tip of the greater troehanter into the center of medullary canal of the pruximal femur before the PFN was inserted under the guidance of K-wire through a small incision made along the K-wire while in group C the PFN was introduced according to the conventional procedure.The operation time,intra-operative blood loss,length of incision,X-ray exposure,duration of in-patient stay and time of bone union in both groups were recorded and compared.Results The mean oper- ation time,mean intraoperative blood loss and mean length of incisions in group MI were 77.20 min,104.20 mL and 5.12 cm respectively and significantly lower than those in group C(P＜0.01).The X-ray exposure and the reduction time in group MI lasted longer than in group C(P＜0.01).The mean time of bone union and in-patient stay in both groups were nearly equal(P＞0.05).At the latest tollow-up,all the fractures united in both groups without nonuuion or delayed union.Conclusion Compared with the conventional protocol,introduction of PFN by a pereutaneuus K-wire inserted into the central medullary canal of the proximal femur is much more minimally in- vasive and effective.
ABSTRACT
Objective To retrospectively evaluate effects of early dynamization of interlocking intramedullary nail on union of tibial shaft fractures.Methods From January 2002 to Septemher 2004,75 patients with tibial shaft fractures were treated in our department with internal fixation using static interlocking iutramedullary nails.Early dy- namization(6 to 10 weeks postoperative)was adopted in 32 patients (the dynamic group) according to the fracture con- ditions,while the other 43 patients were treated without early dynamization (the non-dynamic group).The healing time of fractures and the rate of delayed union in both groups were documented.Results All the cases were followed up for a mean duration of 6.5 months (range,4 to 13 months).The mean healing time was 115.6 days (range,105 to 126 days) in the dynamic group and 124.5 days (range,119 to 133 days) in the non-dynamic group.The difference was statistically significant between the two groups (P＜0.05).There were two cases (6.2%) of delayed union in the dynamic group and four (9.4%) in the non-dynamic group.The difference was not significant (P＞0.05). Conclusion Early dynamization of interlocking intramedullary nail can promote union of tibial shaft fractures.