Which implant is better for the fixation of posterior wall acetabular fractures: A conventional reconstruction plate or a brand-new calcaneal plate?

BACKGROUND: Increased posterior wall acetabular fractures among older adults, require precise treatment to restore stability to the joint, lower the risk of degenerative arthritis, and enhance overall functional recovery. The purpose of this study was to compare the fixation stability and mechanical characteristics of calcaneal buttress plate and conventional reconstruction plate under different loading condition. METHODS: Typical acetabular posterior wall fractures were created on twenty synthetic hemipelvis models. They were fixed with calcaneus plate and reconstruction plate. Dynamic and static tests were performed. Displacements of fracture line and stiffness were calculated. FINDINGS: After dynamic loading, calcaneus plate fixation has significantly less displacement than the reconstruction plate on the superior posterior wall. Under static loading condition, the calcaneus plate group has significantly less displacement than the reconstruction plate group on the inferior posterior part of the fracture. The average stiffness values of the calcaneus plate group and the reconstruction plate group were 265.16±53.98 N/mm and 167.48±36.87 N/mm, respectively and a statistically significant difference was found between the two groups. INTERPRETATION: The calcaneal plate group demonstrated better stability along the fracture line after dynamic and static loading conditions. Especially when the fragment was on the acetabulum's superior posterior, inferior posterior, and inferior rim, Calcaneal buttress plates offer biomechanically effective choices.

Talon cannulated compression device as an alternative in the fixation of acetabulum posterior column fractures: A biomechanical study.

To compare the amount of displacement and rigidity at the fracture line under static & dynamic axial loading and torsional stress of conventional cannulated screw (CS), plate screw fixation including inter-fragmentary screw (PL), and talon cannulated compression device or talon screw in other words (TS) in posterior column fracture models. Synthetic hemipelvis bone models presenting a posterior column fracture were used in this study. Group PL, CS, and TS were created with ten bone models prepared for each group for dynamic and static loading tests and another ten for torsional tests. Rigidity and displacement amounts before and after loading were measured at the reference points AL, BL, and CL, located at the acetabulum's top, middle, and bottom, respectively. Torsional tests for each group were used to calculate torsional rigidity and maximum torque values. In dynamic axial loading tests, Group CS showed more displacement than PL at the BL point (p = 0,032) and Group TS at AL (p = 0,032) and CL (p = 0,004) points. In static axial loading tests, Group CS significantly displaced more than TS at AL and CL points (p = 0,05 and p = 0,014, respectively). Group PL and Group TS exhibited similar behavior in dynamic, static axial loading tests and torsional rigidity. The maximum torque that Group PL could withstand was statistically significantly higher than the other two groups (p <0,001). Talon cannulated screws had promising results in posterior column fractures of the acetabulum, which may decline the need for open surgery for stable fixation.

The effect of the distance between the end point of the osteotomy and the lateral cortex on the lateral cortical hinge fracture in medial opening-wedge high tibial osteotomy.

Background The purpose of this study was to compare the effects of different distances between the end point of the osteotomy and the lateral cortex on the risk of lateral cortical fracture in the medial opening-wedge high tibial osteotomy (MOWHTO) procedure. Methods Eighteen synthetic tibia models were used. Saw cuts were performed on the test models (n=6 for all groups). Wedge gap distance and wedge opening load were evaluated using compression tests. Findings The mean maximum gap distance without a lateral cortical fracture was 19.90 mm in Group 5, 15.49 mm in Group 10, and 11.23 mm in Group 15. The differences between Group 5 and Group 10, Group 5 and Group 15, and Group 10 and Group 15 were statistically significant. The mean load just before the fracture was 13.24 N in Group 5, 18.31 N in Group 10, and 26.16 N in Group 15. The difference between Group 5 and Group 15 was statistically significant. No significant difference was observed between Group 10 and both Group 5 and Group 15. Interpretation As the end point of the osteotomy is brought gradually closer to the lateral cortex, wider gaps can be opened without a lateral cortical fracture. Thus, higher angle corrections can be achieved more safely by bringing the end point of the osteotomy closer to the lateral cortex, which should be preferred to reduce the risk of a lateral cortical hinge fracture during the MOWHTO procedure, from a clinical viewpoint.

The effect of medullary fill on varus collapse in AO 31A3 intertrochanteric (reverse obliquity) fracture treated with cephalomedullary nails.

OBJECTIVE: Cephalomedullary nails are tools commonly used for surgical fixation in proximal femoral fractures. The most common complications in their use are varus collapse and screw cutout of the femoral head. The objective of this study is to examine the effects of intramedullary nail movement on varus collapse and screw cutout. MATERIALS AND METHODS: The study was conducted on 70 composite femur models treated with PFNA. We divided the femurs into 4 groups based on the differences in nail diameter, fracture type and filling of the distal intramedullary area. All femurs were exposed to axial cyclic loading. Each femur was examined in terms of intramedullary nail movement and amount of erosions in femoral medulla [amount of erosion in femoral head (FT distance), amount of erosion in femoral neck (FB distance), amount of erosion in trochanteric major (TB distance) and expansion of trochanter tip (TT distance)]. RESULTS: We found that degree of nail movement in the intramedullary region was inversely correlated with nail diameter and directly correlated with instability of fracture. One of the parameters used to evaluate varus development, FB distance, was affected by the degree of intramedullary nail movement and fracture type. TB distance was affected by nail diameter. CONCLUSIONS: Nail diameter and fracture type are effective in intramedullary nail movement. Varus collapse progress is accelerated by the increase in nail movement in the intramedullary region. Thus, we conclude that it is important to strengthen diaphyseal adherence, which decreases intramedullary movement of the nail. LEVEL OF EVIDENCE: III; well-design case control study.

Could isthmic approach to far lateral disc hernias cause instability?

BACKGROUND: The aim of this study is to investigate the relationship between the degree of instability and the amount of isthmus excised during transpars (isthmic) approach which is accomplished with partial resection of the pars interarticularis used in distal lateral disc herniation. METHODS: Thirty-six ovine lumbar spine segments were used in the study. 25% and 50% of the right side isthmus of each spinal segment were excised. Flexion, lateral bending and axial rotation tests were performed in both groups. FINDINGS: There was no statistically significant difference found between the groups for yield moment, stiffness and ultimate load in flexion tests (p = 0.262, p = 0.749 and p = 0.200, respectively). Statistically significant difference was found between the groups for yield moment, stiffness and maximum load in lateral bending tests (p = 0.016, p = 0.010 and p = 0.016, respectively). There was no statistical difference found between the groups for yield torque and stiffness in axial rotation tests (p = 0.855 and p = 0.314). INTERPRETATION: These results show that a significant loss of resistance especially during the lateral bending loading was occurred with increasing resection portion of isthmus. With the load applied during the lateral bending of the pars interarticularis, the vertebra resected by 50% percent fractured significantly easier in comparison to the vertebra resected by 25% percent. Pars interarticularis is an important structure with an important role in stability. It is presumed that the more defect is created during the drill-up of the pars interarticularis, the more instability will be occurred.

Precontoured buttress plate vs reconstruction plate for acetabulum posterior wall fractures: A biomechanical study.

BACKGROUND: The purpose of open reduction and internal fixation of acetabulum posterior wall fractures is to restore anatomical structure and stability of the hip joint, in order to start weight bearing as soon as possible and prevent hip arthrosis; restoration of the anatomy should preserve function of the joint as well. Although "special shaped precontoured plates" have been developed in recent years for surgical treatment of this region, studies comparing the traditional plates with the newly designed precontoured plates are lacking. AIM: To evaluate the biomechanical properties of precontoured anatomic buttress and conventional curved reconstruction plates (CCRPs) for posterior wall acetabulum fracture treatment. METHODS: Twelve pelvis models were created for testing plate treatment of fracture in the posterior wall of the acetabulum. These 12 pelvis models were used to create 24 hemipelvis models (experimental) by cutting from the sagittal plane and passing over the center of gravity, after which the posterior wall acetabular fractures (of similar type and size) were created. In these experimental models, the right acetabulum was fixed with a 5-hole CCRP, while the left was fixed with a precontoured anatomic buttress plate (PABP). Samples were placed through the test device and were subjected to static load testing, with a constant testing velocity of 2 mm/min until the load reached 2.3 kN or the acetabular fixation failed. Dynamic tests were also performed with sinusoidal wave load, with a maximal load of 2.3 kN and a load ratio of 0.1. RESULTS: The average stiffness values were 460.83 ± 95.47 N/mm for the PABP and 291.99 ± 118.58 N/mm for the 5-hole CCRP. The precontoured anatomic acetabulum buttress plates had significantly higher rigidity than the CCRPs (P = 0.022). There was a statistically significant difference between the unloaded and 2.3 kN-loaded values of AL (posterosuperior fracture line vertical to the ground surface) and CL (posteroinferior fracture line vertical to the ground surface) parameters for both the PABPs and the 5-hole CCRPs (P = 0.036 and P = 0.045, respectively). According to the static tests, the amount of total displacement was significantly less in the PABPs than in the CCRPs. Comparative analysis of the displacement in the BL (posterior wall fracture line horizontal to the ground) parameter yielded no statistically significant differences between the PABP and the 5-hole CCRPs (P = 0.261). CONCLUSION: PABP provides more stable fixation in acetabulum posterior wall fractures than 5-hole CCRP, allowing for proximal or distal fracture line screw application without reshaping.