ObjectiveTo develop an instrument for sacroiliac joint fixation with less injury and less complications. MethodsFirstly, 18 adult pelvic specimens (8 males and 10 females) were used to measure the anatomical data related to the locking plates and locking screws on the sacrum and ilium, and the polyaxial locking plate screw system of the sacroiliac joint was designed according to the anatomic data. This system was made of medical titanium alloy. Then 4 adult male plevic specimens were harvested and the experiment was divided into 3 groups:group A (normal pelvic), group B (the dislocated sacroiliac joint fixed with sacroiliac screws), and group C (the dislocated sacroiliac joint fixed with polyaxial locking plate screw system). The vertical displacement of sacroiliac joint under the condition of 0-700 N vertical load and the horizontal displacement on angle under the condition of 0-12 N·m torsional load were compared among the 3 groups by using the biological material test system. Finally, the simulated application test was performed on 1 adult male cadaveric specimen to observe soft tissue injury and the position of the locking plate and screw by X-ray films. ResultsAccording to the anatomic data of the sacrum and ilium, the polyaxial locking plate screw system of the sacroiliac joint was designed. The biomechanical results showed that the vertical displacement of the sacroiliac joint under the condition of 0-700 N vertical load in group A was significantly bigger than that in group B and group C (P < 0.05), but there was no significant difference between group B and group C (P>0.05). The horizontal displacement on angle under the condition of 0-12 N·m torsional load in group A was significantly less than that in group B and group C (P < 0.05). The horizontal displacement on angle under the condition of 0-6 N·m torsional load in group B was bigger than that in group C, and the horizontal displacement on angle under the condition of 6-12 N·m torsional load in group B was less than that in group C, but there was no significant difference between group B and group C (P>0.05). The test of simulating application showed that the specimen suffered less soft tissue injury, and this instrument could be implanted precisely and safely. ConclusionThe polyaxial locking plate screw system of the sacroiliac joint has the advantages of smaller volume and less injury; polyaxial fixation enables flexible adjustment screw direction. The simulated application test shows satisfactory fixing effect.
ObjectiveTo explore the technique of arthroscopic resection of benign tumor in the knee posterior septum and to evaluate its clinical results. MethodsBetween June 2008 and June 2012, 12 cases of benign tumor in the knee posterior septum were treated by arthroscopic surgery. There were 8 males and 4 females with an average age of 36.5 years (range, 22-50 years). The average disease duration was 8.4 months (range, 3 months to 2 years). Of 12 cases, there were 2 cases of chronic synovitis, 5 cases of ganglion, 4 cases of tenosynovial giant cell tumor, and 1 case of synovial hemangioma; solitary tumor involved in the knee posterior septum in 10 cases, and in the posterior septum and other part of the knee in 2 cases. All the patients underwent tumor removal under arthroscope with routine anterolateral and anteromedial portal, additional posteromedial portal and/or posterolateral portal. Trans-septal approach was used in 6 cases because the tumors located in the middle of the posterior septum. ResultsAll wounds healed by first intention with no complications such as infection, haematoma in the knee, injury of vessels and nerves, deep vein thrombosis, osteofascial compartment syndrome, or cutaneous necrosis. All patients were followed up 12-46 months with an average of 18.5 months. All patients achieved relief of knee pain and improvement of knee movement. The range of motion of the knee was significantly improved from (57.08±12.52)° at pre-operation to (120.83±13.95)° at last follow-up (t=-12.84, P=0.00). The visual analogue scale (VAS) score was significantly reduced from 5.00±1.04 at pre-operation to 1.50±0.91 at last follow-up (t=-18.00, P=0.00). The Lysholm score was significantly improved from 49.50±9.07 at pre-operation to 84.58±6.82 at last follow-up (t=-8.04, P=0.00). ConclusionThe benign tumor in the knee posterior septum can be completely resected under arthroscope, and the procedure is minimally invasive and useful to the restore knee function.
ObjectiveTo observe the characteristics of acetabular labrum injury in Pipkin fractures and the effectiveness of repairing the labrum with suture anchor. MethodsBetween July 2010 and July 2013, 10 cases of Pipkin fractures accompanied by acetabular labrum injury were treated. There were 7 males and 3 females with an average age of 32.5 years (range, 24-56 years). The causes of injury included traffic accident in 8 cases and falling from height in 2 cases. According to the Pipkin classification criteria, there were 6 cases of type Ⅱ, 2 cases of type Ⅲ, and 2 cases of type Ⅳ. The average interval from injury to operation was 8 days (range, 6-14 days). All the patients underwent open reduction and internal fixation through transtrochanteric approach with trochanteric osteotomy, and repair the labrum with suture anchor. The effectiveness was evaluated according to the Thompson & Epstein scoring scales after operation. ResultsAll incisions healed primarily without early complication of deep infection or deep vein thrombosis of lower limb. All the cases were followed up 22 months on average (range, 12-48 months). X-ray films showed that all osteotomies and acetabular fractures healed within 3-4 months, femoral head and femoral neck fracture healed within 6-11 months. MRI examinations showed that all repaired acetabular labrums well healed. One case had necrosis of the femoral head at 12 months after operation, and was treated by total hip arthroplasty. According to the Thompson & Epstein scoring scales at last follow-up, the results were excellent in 5 cases, good in 3 cases, fair in 1 case and poor in 1 case, with an excellent and good rate of 80%. ConclusionThe diagnosis of acetabular labrum injury can be easily missed during Pipkin fracture, preoperative diagnosis should be combined with hip MRI. Trochanteric osteotomy through transtrochanteric approach, and repairing the labrum with suture anchor can restore the hip function effectively.