Correction of deformities around the knee joint using external fixator-assisted internal fixation / 中华骨科杂志

ABSTRACT

Objective To evaluate the clinical outcomes and correction accuracy of deformities around the knee joint using external fixator-assisted internal fixation (FAIF).Methods From January 2014 to March 2018,data of 15 patients (17 bone segments) with deformities around the knee joint who had been corrected with external fixator-assisted internal fixation were retrospectively analyzed.There were 6 males and 9 females,with an average age of 39 years (range,21-60 years).There were 9 patients with genu varus and 6 with genu valgus.All the 15 patients had shortening ranging from 5 to 22 mm,with an average of 12 mm.Unilateral external fixator was used to stabilize the osteotomy site intraoperatively until the satisfied mechanical axis was acquired.Then the plate or Intramedullary nail was inserted and fixed,the external fixator was removed after internal fixation.Results Femur osteotomy was done in 7 patients and tibia osteotomy was done in 6 patients,while 2 patients had osteotomy in both tibia and femur.Intramedullary nailing was used in 2 bone segments,and plate was used in 15 bone segments.The correction of angle ranged from 7° to 22°,with an average of 12.5°.The correction of the 9 cases of genua varus ranged from 10° to 22°,with an average of 17.6°.The correction of the 6 cases of genu valgum ranged from 7° to 13°,with an average of 10.4°.The mean time to achieve union of the osteotomy sites was 3.5 months (range,2.5-5.0 months).All the 15 patients were followed up for 8-48 months (average,23 months).The mechanical axis deviation (MAD) was 5.93 mm (range,0-15 mm) after operation which was 34.8 mm (range,8-55 mm) before operation.The mean post-operative mechanical lateral distal femoral angle (mLDFA) was 87.5° (range,84°-90°) which was 76.1° (range,66°-82°) before operation.The mean medial proximal tibia angle (MPTA) was 87.8° (range,86°-89°) which was 76.8° (range,68°-80°) before operation.There were no deep infection and neurovascular injury.Conclusion The FAIF not only has the advantage of minimal invasiveness and easy adjustment,but also can avoid uncomfortableness and complications of long-term of wearing the external fixator.It is an accurate and safe method to correct the deformities around the knee joint.