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 design a new type of transarticular cuboid bone plate by measuring and collecting the anatomic data of the articular surface around cuboid, and to carry out comparative biomechanical study. MethodsThe angle α (between the fifth metatarsocuboid joint and the fifth metatarsal bone) and the angle β (between the fifth metatarsocuboid joint and the calcaneocuboid joint) were measured in 100 adults on medial oblique X-ray film and 30 adult foot specimens. Based on literature data, the transarticular cuboid bone plate was designed with an angle α of 70° and an angle β of 30°. Six adult cadaver feet were chosen and were transected approximately 15 cm proximal to the ankle. Five strain gauges were placed at the calcaneus, cuboid, and the fourth and fifth metatarsal bones. The vertical pressure was loaded on the foot at 0-600 N, the strain value was measured. Then the cuboid fracture model was established and 600 N load was given on foot to measure the strain value and compare with the strain value before fracture. The specimens were randomly divided into groups A and B (n=3). Fracture was fixed with transarticular cuboid bone plate and 9 screws in group A and with double plate and 8 screws in group B, then the 600 N load was given to measure the strain value and vertical displacement of the fracture fragments. ResultsAfter loads of 0-600 N on the foot, the strain value of the 5 points showed an increased trend. No significant difference was found in the strain value between pre- and post-fracture at a, d, and e points P>0.05), but it was significantly larger at post-fracture than pre-fracture at b and c points (P<0.05). After fracture fixation, no significant difference was shown in the strain value at 5 points between groups A and B when loads of 0-600 N was given P>0.05). The experimental data showed that the strain value change mainly focused on the fracture site under the same load, so the strain value after fracture fixation was similar to that before fracture at b and c points P>0.05). The vertical displacement values of medial and lateral fracture fragments in group A[(0.804±0.011) mm and (0.672±0.036) mm] were significantly less than those in group B[(1.126±0.083) mm and (1.007±1.103) mm] (t=-6.711, P=0.003; t=-5.307, P=0.006). ConclusionThrough biomechanical study, a new type of transarticular cuboid bone plate has better fixation effect.
Different generations of biomedical materials are analyzed in this paper. The current clinical uses of plates made of metals, polymers or composite materials are evaluated, and nano hydroxyapatite/polylactic acid composites and carbon/carbon composite plates are introduced as emphasis. It is pointed out that the carbon/carbon composites are of great feasibility and advantage as a new generation of biomedical materials, especially in the field of bone plate. Compared to other biomaterials, carbon/carbon composites have a good biocompatibility and mechanical compatibility because they have similar elastic modulus, porosity and density to that of human bones. With the development of the technology in knitting and material preparation, carbon/carbon composite plates have a good application prospect.
Objective To find out an ideal method of internal fixation for the treatment of fractures of proximal radius. Methods From August 2001 to April 2004, 24 patients suffering from fractures of proximal radius were treated with NiTi shape memory alloy embracing fixator. Of 24 patients, there were 19 males and 5 females, aging from 16 to 48 years; there were 9 cases of wrestling injury, 5 cases of crush injury, 4 cases of traffic accident injury, 3 cases of direct violence impact injury and 3 cases of high falling injury. All patients were given operation according to fix method of the shape memory alloy embracing fixator. All cases were regularly followed up to observe the fracture healingand functional recovery. Results All cases were followed up postoperatively from 4 months to 21 months with an average of 10 months. No complication occurred during operation and after operation. Healing by first intention was achieved. X－ray showed that all cases achieved clinical union 8－12 weeks after operation. According to Anderson’scriteria and the results were excellent in 18 cases, good in 5 cases, and fairin 1 case. The excellent and good rate was 95.83 %. Conclusion The internal fixation with shape memory alloy embracing fixator has as follows adventages: less trauma, esay－to－do, stable fixation, better tissue compatibility and less complication in treating fractures of proximal radius. This method can enhance the fracture healing and functional recovery. So it is a better method to treat fractures of proximal radius.
To investigate the method and cl inical effect of double-plating fixation in treatment of distal humerus fractures. Methods From April 2003 to January 2009, 21 patients with distal humerus fracture were treated with l imited contact compression plate and reconstruction plate via posterior elbow incision and approach inside and outside the edge of both sides of the triceps. There were 12 males and 9 females, aged from 20 to 63 years (39 years on average). The causes of injury were fall ing in 13 cases, traffic accident in 6 cases, and fall ing from height in 2 cases. According to the classification of Association for the Study of Internal Fixation (AO/ASIF), 8 cases were classified as type 12-B1, 2 as type 12-B2, 7 as type12-B3, 3 as type 13-A2, and 1 as type 13-A3. The course of disease averaged 4.8 days. Results Secretion was observed at incision in 1 case 2 weeks after operation, and incision healed after dressing change; other incisions healed by first intention. Transient numbness of ring and l ittle fingers occurred in 2 cases 2 days after operation; no iatrogenic nerve paralysis occurred. All patients were followed up 13 to 18 months (15 months on average). The X-ray films showed bone healed 6 months after operation. No postoperative joint adhesion occurred, and the motion of elbow joint ranged from 0° to 135°. According to Morrey evaluation standard, the results were excellent in 17 cases, good in 2 cases, and fair in 2 case; the excellent and good rate was 90.5%. Conclusion Double-plating fixation has the advantages of wide indications, rigid internal fixation, and significant curative effects in treatment of distal humerus fractures.
Objective?To analyse the procedure and effectiveness of internal fixation in treatment of displaced radial head fractures.?Methods?Between August 2005 and May 2009, 35 patients with displaced radial head fractures underwent open reduction and internal fixation with SmartNail? and/or AO mini-plates. There were 28 males and 7 females with an average age of 28.4 years (range, 17-48 years). The injury mechanism included traffic accident in 16 patients, falling in 13, and falling from height in 6. According to Mason classification, 21 fractures were rated as type II, 9 as type III, and 5 as type IV. All fracturs were closed fractures. Six cases complicated by radial neck fractures, 1 case by olecranon fracture, 3 by posterior dislocations of the elbow, 1 by posterior dislocation of the elbow and coronoid process fracture, and 3 by medial collateral ligament injuries. The time from injury to operation was 3 to 7 days.?Results?Except 1 patient whose incision healed by second intention, healing of incision by first intention was achieved in the other patients. All patients were followed up 12-25 months with an average of 17 months. The average fracture healing time was 10.2 weeks (range, 8-16 weeks). At last follow-up, the average flexion and extension of the elbow was 119° (range, 95-145°). The average arc of forearm rotation was 126° (range, 90-175°). According to elbow functional evaluation criteria by Broberg and Morrey, the results were excellent in 18 cases, good in 13, and fair in 4; the excellent and good rate was 88.6%.?Conclusion?In treatment of displaced radial head fractures, open reduction and internal fixation can be performed with SmartNail? and/or AO mini-plates based on different fracture types and the short-term effectiveness is satisfactory.
目的 探討應用經皮接骨板固定技術（MIPPO）結合鎖定鋼板（LCP）固定治療脛腓骨骨折的療效。 方法 2009年11月－2012年1月應用MIPPO技術結合LCP固定治療脛腓骨干骨折62例。其中男42例，女20例；年齡16～85歲，平均45歲。骨折按AO分型：A1型10例，A2型3例，A3型3例，B1型18例，B2型8例，B3型4例，C1型10例，C2型5例，C3型1例。閉合骨折47例；開放骨折15例，根據Gustilo-Anderson分型，Ⅰ型8例，Ⅱ型6例，ⅢA型1例。傷后內固定時間3 h～10 d，平均6 d。 結果 開放骨折有3例傷口Ⅱ期愈合，其中1例傷口皮緣壞死，1例鋼板部分外露經換藥和清創減張縫合后傷口愈合，1例骨外露經皮瓣轉移愈合；其余患者術后傷口均Ⅰ期愈合。62例均獲隨訪，隨訪時間6～16個月，平均9個月。無感染、神經損傷、骨筋膜室綜合征發生。術后2～4個月骨折均愈合。根據Johner-Wruhs療效評價，優48例，良14例；開放性骨折15例中優10例，良5例。 結論 MIPPO技術結合LCP固定治療脛腓骨干骨折，具有創傷小、骨折愈合快等優點。