Treatment of isolated posterior coronal fracture of the lateral tibial plateau through posterolateral approach for direct exposure and buttress plate fixation

Purpose  To present a case series of patients with isolated posterior coronal fractures of lateral tibial plateau treated by direct exposure and buttress plate fixation through posterolateral approach. Methods  Between May 2007 and April of 2008, eight middle aged patients were identified that had isolated posterior coronal fractures of the lateral tibial plateau. All eight patients underwent direct fracture exposure, reduction under visualization, and buttress plate fixation through posterolateral approach. Results  There were 1 case of split, two cases of pure depression and five cases of split-depression fractures. Four were associated fibular head split fractures without common peroneal nerve injuries. Five patients were injured from a simple fall on riding electrical bicycle while the knee was relaxed in 90° position The articular displacement (8 cases) measured in CT scan was 10.5 mm in average (range 8–15 mm). The cortical split length (from the articular rim to the distal tip, 6 cases) was 2.8 cm in average (range 2.4–3.5 cm). The articular reduction was perfect in seven (absolutely no step-off) and imperfect in 1(<2 mm step-off) as measured by X-ray. With a mean follow-up of 10 months (6 cases > 12 months), the average range of motion arc was 119°, four patients have flexion lag 10°–20°. The average SMFA dysfunction score was 15.8, and average HSS score was 98. All eight patients stated they were highly satisfied. Conclusions  Direct posterolateral approach by dividing lateral border of soleus muscle, provides excellent fracture reduction under visualization and internal buttress plate fixation for posterior coronal fracture of the lateral tibial plateau. Good functional results and recovery can be expected.     

Effect of articular step-off and meniscectomy on joint alignment and contact pressures for fractures of the lateral tibial plateau

OBJECTIVES: To determine the effects of intraarticular step-off and lateral meniscectomy on the alignment of the articular axis, contact area, and pressures for lateral tibial plateau fractures. DESIGN: Biomechanical cadaver study. INTERVENTION: Six fresh cadaveric knees were used. A simulated split fracture of the lateral tibial plateau was reproducibly created by osteotomies, and articular step-offs of zero, one, two, four, and six millimeters were achieved by using support shims. The knee was loaded with 500 newtons in 0 degrees and 350 newtons in 30 degrees of flexion. A digital camera determined changes in the alignment of the articular axis, and F-Scan sensors were inserted into the medial and lateral joint compartments to determine the pressures and pressure distributions. MAIN OUTCOME MEASUREMENT: Each specimen was tested at step-offs of zero, one, two, four, and six millimeters, with the presence or absence of the lateral meniscus. The changes in alignment of the articular axis, the contact area, and the average and maximum contact pressures for each condyle were obtained. RESULTS: Increased articular step-off heights progressively increased valgus angulation and average and maximum contact pressures and progressively decreased contact areas in lateral compartment. At a six-millimeter step-off with 0 degrees of flexion, the valgus angle increased an average of 7.6 degrees, and average contact pressures and maximum contact pressures increased an average of 208 percent and 97 percent, respectively, and contact area decreased an average of 33 percent (p < 0.05). Meniscectomy increased valgus angles by an average of 38 percent and contact pressures by an average of 45 percent and decreased contact areas by 26 percent in the lateral compartment at the same articular step-off heights (p < 0.05). CONCLUSION: The results of this study show the importance of decreasing articular step-off heights in treating lateral tibial plateau split fractures, particularly if a meniscectomy is performed.     

Biomechanical analysis of dual versus lateral locked plating in elderly bicondylar tibial plateau fractures: Does medial comminution matter?

ObjectiveTo assess dual plating versus lateral locked plate fixation of bicondylar tibial plateau fractures in an elderly cadaveric model with and without medial bone lossParticipants10 pairs of elderly (range 78–93 years of age) fresh frozen tibias.InterventionBicondylar tibial plateau fractures were created reproducing AO/OTA 41 C1 (without medial bone loss) and C2 fractures (with medial bone loss). Cadavers were randomized to 4 different groups. Groups 1 and 2 were 41 C1 fractures and fixated with either dual or lateral plating, respectively. Groups 3 and 4 were fixated in a similar fashion with medial metaphyseal bone loss (41 C2 fracture) with dual plating Group 3 and lateral plating group 4. Lateral plating consisted of a 3.5 mm 5-hole lateral plate (ALPS, ZimmerBiomet) with 6 bicortical locking screws proximally and two diaphyseal screws. Dual plating groups underwent lateral plating and additional 3.5 mm 5-hole posteromedial 1/3 tubular plate (ZimmerBiomet) placed at the apex of the fracture with two shaft screws and one unicortical screw proximally. Specimens were tested in a Mechanical Testing System (MTS) machine loading both condyles.Outcome measurementsSpecimens were loaded to 300 N and coronal alignment obtained. Specimens were then cycled from 100 N to 700 N for 5000 cycles at 2 Hz. Average axial displacement, maximal displacement, average force and coronal alignment after 5000 cycles were recorded. Lastly, force to failure was recorded at 100 N/sec.ResultsMean axial displacement was 4.21 mm ranging from 3.12 mm in group 1 to 5.92 mm in group 4 (P = 0.51). Failure force averaged 3340 N ranging from 4342 N in group 1 to 2433 N in group 4 (P = 0.36). Maximal displacement ranged from 3.69 mm in group 1 to 7.37 mm in group 4 (P = 0.21). Change in coronal alignment ranged from 0.98° in group 1 to 1.97° in group 4 (P = 0.45). No statistically significant difference was noted between all four groups for all data points.ConclusionThe results of this study demonstrate that a lateral locked plate may offer an alternative means of fixation in AO/OTA 41 C1 and C2 fractures.     

The anterolateral supra-fibular-head approach for plating posterolateral tibial plateau fractures: A novel surgical technique

ObjectiveThe posterolateral (PL) tibial plateau quadrant is laterally covered by the fibular head and posteriorly covered by a mass of muscle ligament and important neurovascular structures. There are several limitations in exposing and fixing the PL tibial plateau fractures using a posterior approach. The aim of this study is to present a novel anterolateral supra-fibular-head approach for plating PL tibial plateau fractures.MethodsFive fresh and ten preserved knee specimens were dissected to measure the following parameters:1) the vertical distance from the apex of the fibular head to the lateral plateau surface, 2) the transverse distance between the PL platform and fibula collateral ligament (FCL), and 3) the tension of the FCL in different knee flexion positions. Clinically, isolated PL quadrant tibial plateau fractures were treated via an anterolateral supra-fibular-head approach and lateral rafting plate fixation. The outcome of the patients was assessed after a short to medium follow-up period.ResultsThe distance from the apex of the fibular head to the lateral condylar surface was 12.2 ± 1.6 mm on average. With the knee extended and the FCL tensioned, the transverse distance between the PL platform and the FCL was 6.7 ± 1.1 mm. With the knee flexed to 60° and the FCL was in the most relaxed position, the distance increased to 21.1 ± 3.0 mm. Clinically, a series of 7 cases of PL tibial plateau fractures were treated via this anterolateral supra-fibular-head approach. The patient was placed in a lateral decubitus position with the knee flexed to approximately 60 degrees. After the posterior retraction of the FCL, the plate was placed more posteriorly to provide a raft or horizontal belt fixation of the PL tibial plateau fragment. After an average of 14.3 months of follow up, the knee range of motion(ROM) was 121.4°±8.8° (range: 105°-135°), the HSS score was 96.7 ± 2.6 (range: 90-100), and the SMFA dysfunction score was 22.4 ± 3.8 (range: 16-28) points.ConclusionThe anterolateral supra-fibular-head approach can provide direct visualization of the posterolateral tibial plateau quadrant and put the plate more posteriorly to provide a raft for the fragments such that good clinical outcomes can be anticipated.     

Lumbar facet joint and intervertebral disc loading during simulated pelvic obliquity

Background contextIntervertebral disc and facet joints are the two primary load-bearing structures of the lumbar spine, and altered loading to these structures may be associated with frontal plane spinal deviations.PurposeTo determine the load on the lumbar facet joint and intervertebral disc under simulated frontal plane pelvic obliquity combined loading, an in vitro biomechanical study was conducted.Study design/settingAn in vitro biomechanical study using a repeated-measures design was used to compare L4–L5 facet joint and intervertebral disc loading across pure moment and combined loading conditions.MethodsEight fresh-frozen lumbosacral specimens were tested under five loading conditions: flexion/extension, lateral bending, axial rotation using pure moment bending (±10 Nm), and two additional tests investigating frontal plane pelvic obliquity and axial rotation (sacrum tilted left 5° and at 10° followed by a ±10-Nm rotation moment). Three-dimensional kinematics, facet load, and intradiscal pressures were recorded from the L4–L5 functional spinal unit.ResultsSagittal and frontal plane loading resulted in significantly smaller facet joint forces compared with conditions implementing a rotation moment (p<.05). The facet joint had the highest peak load during the 10° combined loading condition (124.0±30.2 N) and the lowest peak load in flexion (26.8±16.1 N). Intradiscal pressure was high in lateral flexion (495.6±280.9 kPa) and flexion (429.0±212.9 kPa), whereas intradiscal pressures measured in rotation (253.2±135.0 kPa) and 5° and 10° combined loading conditions were low (255.5±132.7 and 267.1±127.1 kPa, respectively).ConclusionsFacet loading increased during simulated pelvic obliquity in frontal and transverse planes, whereas intradiscal pressures were decreased compared with sagittal and frontal plane motions alone. Altered spinopelvic alignment may increase the loads experienced by spinal tissue, especially the facet joints.     

选择性胫骨外髁U形截骨入路治疗胫骨外侧平台塌陷粉碎骨折

目的:探讨选择性胫骨外髁"U "形截骨入路治疗胫骨外侧平台塌陷粉碎骨折的方法和临床疗效。方法:自2014年1月至2019年10月,采用选择性胫骨外髁" U"形截骨入路对15例胫骨外侧平台塌陷粉碎骨折患者进行手术治疗,其中男9例,女6例;年龄25~70(38.5±7.7)岁。按照胫骨平台外侧髁骨折ABC分型,A型2例,B型6例,BC型4例,C型3例;合并内侧平台骨折5例;左膝8例,右膝7例。伤后至就诊时间1~14(3.4±1.2) d。所有患者CT提示胫骨外侧平台塌陷>2 mm,粉碎骨块>2块,胫骨外侧髁皮质完整。术后12个月采用Rasmussen骨折复位解剖学评分评价骨折复位情况,并采用Rasmussen功能评分评价膝关节功能。结果:15例患者选择性"U "形截骨一次成功,手术时间55~110(85.6±20.0) min,外侧平台手术时间20~60(30.5±10.5) min。所有患者获随访,时间12~24(14.6±2.5)个月。骨折愈合时间12~24(13.6±3.6)周。术后12个月膝关节Rasmussen骨折复位解剖学评分14~18(17.5±0.3)分,其中优13例,良2例。膝关节Rasmussen功能评分13~30(26.8±2.5)分;其中优12例,良1例,可2例。2例外侧平台高度分别丢失2 mm和4 mm,1例膝关节5°外翻畸形,1例关节僵硬(10°~100°)。未发生腓总神经损伤、腘血管损伤,术后无感染、内固定失效等严重并发症。结论:采用选择性胫骨外髁" U"形截骨入路治疗胫骨外侧平台塌陷粉碎性骨折,具有手术切口简单、骨折显露直接、复位固定准确、手术时间短,并发症少等优点,是一种有效、可靠的方法。     

Gait analysis and clinical outcome in patients after pilon fracture surgery

BackgroundIn this study kinematic parameters, radiographic findings and PROM in pilon fractures after operative treatment were compared with healthy subjects.Methods16 patients treated with osteosynthesis after pilon fracture underwent kinematic analysis with the OFM. Fractures were evaluated for post-operative step-off and gap on CT-scans and PROM were collected. Results were compared to 10 healthy persons.ResultsRange of motion (ROM) crural was lower in the flexion/extension for pilon fractures (10.03 vs. 13.15, p = 0.017). The ROM in the inversion/eversion was low, but ROM in the abduction/adduction was higher. Correlations were found between flexion/extension and AO-classification (r = ?0.357 p < 0.05), PROM score of the AOFAS (r = 0.445 p < 0.01), post-operative gap and step-off in the tibia plafond.ConclusionPilon fractures showed decreased ROM between the hindfoot and tibia in the sagittal and transverse plane, but increased ROM in the frontal plane during push-off phase as compensatory kinetics. ROM showed significant correlations with PROM and intra-articular step-off and gap in the tibia plafond.     

Opening wedge high tibial osteotomy for medial compartment knee osteoarthritis: Planning and improving outcomes: Case series and literature review

BackgroundOpening wedge high tibial osteotomy (OWHTO) is a safe surgical procedure to treat medial compartmental osteoarthritis caused by a varus deformity. Over-correction of this varus deformity can lead to lateral compartment over-loading. In our study, we planned our correction by using the mechanical axis deviation (MAD).PurposeThe purpose of this study is to evaluate the clinical and radiological results of OWHTO based on planning using the MAD measurements.Study DesignRetrospective Case Series.Methods14 patients with Kellgren- Lawrence classification (KL) grade 3 or above underwent OWHTO, with plans to have the mechanical axis pass through 5–15 mm lateral to the center of the tibial plateau. Pre-operative and post-operative radiographic measurements were made and compared using the student t-test. SF-36 scores were obtained for clinical performance.ResultsOur patients experienced MAD from 25.9 mm medial to the center of the tibial plateau pre-operatively to 12.7 mm lateral to the center of the plateau post-operatively. The mean change in MAD was 38.7 mm (p < 0.0001). The accuracy of our correction compared to the planned MAD was 98.3%. The mechanical axis angle shifted from 7.35° of varus to 3.5° of valgus (p < 0.0001). All patients had post-operative alignments of 1–6° of valgus, with 11 of out the 14 patients with alignments less than 5° of valgus, preventing over-loading of the lateral compartment.ConclusionUsing MAD measurements is an accurate planning method for OWHTO that corrects varus deformity without over-loading the lateral compartment, and leads to improved clinical outcomes.     

A radiographic zone-based approach to predict meniscus injury in lateral tibial plateau fracture

ObjectivesThere is limited data regarding meniscal injury and it's association to fracture location and articular impaction/displacement (AID) in tibial plateau fractures. The purpose of this study was to predict lateral meniscal injury in tibial plateau fractures, based on location and extent of AID as visualized on pre op CT images.DesignRetrospective review study.SettingLevel I academic trauma center.PatientsWe retrospectively reviewed lateral tibia plateau fracture patients that were treated operatively using CPT codes 27535 and 27536. Two hundred patients were identified. Inclusion criteria were lateral tibia plateau fracture, age of 18 years or older, and documented direct examination of lateral meniscus integrity intraoperatively. Seventy patients met inclusion criteria.InterventionThe injured lateral tibial plateau was divided into four quadrants on pre-operative CT and maximum AID was measured. The zone of fracture was defined as the location of largest AID (Image-1). All patients had an arthrotomy at the time of surgery to evaluate the integrity of the meniscus. Intra operative data regarding meniscal integrity and preoperative CT data were analyzed. Logistic regression was used to estimate what effect zone and amount of AID had on predicting the meniscal injury. Receiver operating characteristic (ROC) analysis was performed to determine cut off points for high sensitivity/specificity.Main outcome measurementsAmount and area of depression in the lateral tibial plateau as relates to meniscal injury.ResultsMean age was (45.1 ± 12.9) years. Twelve had Schatzker type I and 58 had type II fractures. Twenty-two patients had meniscus injury (MI) and forty-eight patients did not have a meniscus injury (NMI). Mean AID for MI was 12.48 mm ± 7.17 mm and 6.4 mm ± 4.3 mm for NMI (p<0.01). In MI group, largest AID was in Posterolateral (PL) zone(17.58 mm ± 8.9 mm) followed by Anteromedial (AM) zone (13.3 mm ± 7.2 mm) and Anterolateral (AL) zone (9.4 mm ± 5.8 mm). In NMI group largest AID was in AL zone (8.52 mm ± 2.6 mm) followed by AM zone (8.04 mm ± 5.4 mm) and PL zone (7.75 mm ± 2.35 mm). Patients with PL zone involvement had a lower meniscus tear rate compare to other zones. Logistic regression revealed that for every 1 mm increase in AID there is a 21% increase chance of meniscus tear (p<0.01). Comparison of the zones indicated that for the same AID, AL and AM zone fractures have 7.3 and 5.6 times increase risk of meniscus tear, respectively, as compared to PL zone (p<0.05). ROC analysis revealed that AID of 4.3 mm as a cut off point provides 100% sensitivity for diagnosis of meniscus tear.ConclusionWith 1 mm increase in AID there is a 21% increase in chance of meniscal tear. With the same AID, AL and AM zone fractures have a significantly higher chance of having a meniscal tear. AID of 4.3 mm provides 100% sensitivity to predict meniscal tear in lateral tibia plateau fracture. These values are useful in predicting pre op meniscal tear without MRI.     

Lower limb alignment in healthy Japanese adults

BackgroundKnowledge regarding the normal alignment of the lower limb is important when considering alignment for total knee arthroplasty. However, few studies have explored the lower limb alignment of healthy Japanese subjects.MethodsBetween July and October 2020, we performed whole leg standing radiography of 120 legs of 60 healthy adult Japanese volunteers aged <50 years in the closed-leg stance. The measurement parameters were hip knee ankle angle (positive for varus), percentage of constitutional varus (hip knee ankle angle ≥ 3°), mechanical axis deviation ratio, mechanical lateral distal femoral angle, medial proximal tibial angle, joint line convergence angle (positive for lateral opening), and tibial joint line angle (positive for medial inclination).ResultsThe mean measured values for all volunteers, men and women, were as follows: hip knee ankle angle (°), 2.3, 2.6, and 2.0; mechanical axis deviation ratio, 35.8, 35.6, and 36.9; mechanical lateral distal femoral angle (°), 86.7, 87.0, and 86.7; medial proximal tibial angle (°), 85.6, 85.0, and 86.2; joint line convergence angle (°), 0.6, 0.3, and 0.8; and tibial joint line angle (°), ?1.0, ?0.7, ?1.4, respectively. The percentage of constitutional varus was 35.8% overall, 35.8% in men and 35.3% in women. Only the medial proximal tibial angle was smaller in men than that in women (p = 0.003).ConclusionsThe mechanical lateral distal femoral and medial proximal tibial angles were smaller, hip knee ankle angle was larger, and percentage of constitutional varus was higher in Japanese subjects than those reported for subjects in other countries. Our findings improve the understanding of Japanese-specific alignments when considering alignment for lower limb surgery, especially, total knee arthroplasty.     

Dynamic hip kinematics before and after periacetabular osteotomy in patients with dysplasia

BackgroundWe prospectively analyzed the hip kinematics in patients with developmental dysplasia of the hip (DDH) before and after periacetabular osteotomy (PAO) and in healthy subjects while squatting to determine the influence of coverage of the femoral head on hip kinematics.Methods14 hips in 14 patients with DDH and 10 hips in 10 volunteers were included. Continuous radiographs while squatting and computed tomography images were obtained to assess the in vivo kinematics of the hip and the rim-neck distance using density-based 3D-to-2D model-to-image registration techniques.ResultsThe maximum hip flexion angles were 100.4° and 94.9° before and after PAO (p = 0.0863), respectively. The maximum hip flexion angles after PAO did not significantly differ from those of normal hips (102.2°; p = 0.2552). The hip abduction angles at maximum hip flexion were 31.7° and 26.2° before and after PAO (p = 0.1256), respectively. The rim-neck distance decreased from averaged 12.2 mm–8.9 mm (p = 0.0044) after PAO. The lateral center edge angle (LCEA) and anterior center edge angle (ACEA) significantly improved 14.7°–42.4° and 50.4°–54.0° after PAO (p < 0.0001, p = 0.0347), respectively; in particular, the ACEA after PAO did not significantly differ from that in the normal hips (p = 0.1917). The ACEA was not correlated with hip flexion, or the rim-neck distance (p = 0.9601, 0.8764). The LCEA was also not correlated with hip abduction (p = 0.1683).ConclusionPatients after PAO showed no significant difference in maximum hip flexion while squatting compared to before PAO and normal hips. Horizontalized weight-bearing acetabulum with normalized ACEA could be adequate correction of the acetabular fragment to restore hip RoM without coxalgia that induce the inability to perform squats after PAO.     

Intra-articular corrective osteotomy for intra-articular malunion of distal radius fracture using three-dimensional surgical computer simulation and patient-matched instrument

BackgroundCorrective osteotomy of malunited intra-articular distal radius fracture is challenging. In this study, we investigated the results in patients with malunited intra-articular distal radius fracture who underwent intra-articular corrective osteotomy through an extra-articular approach using three-dimensional (3-D) computer simulation and a patient-matched instrument (PMI).MethodsWe retrospectively studied five consecutive patients with symptomatic malunited intra-articular distal radius fracture who underwent corrective osteotomy using a PMI. The maximal step-off on computed tomography and the deformity angle on plain radiographs were evaluated. The clinical examination parameters included range of motion (ROM), grip strength, pain according to visual analog scale (VAS), and Patient-Rated Wrist Evaluation (PRWE) score.ResultsThe maximal step-off was significantly reduced from 4.9 ± 1.8 to 1.0 ± 0.2 mm (p = 0.008). The absolute differences between the affected side and the normal contralateral side in radial inclination were significantly reduced from 5.4° ± 3.4°–1.2° ± 1.1° (p = 0.043). These differences were not significantly reduced postoperatively in the volar tilt and ulnar variance. VAS was significantly reduced from 4.1 ± 1.6 to 0.9 ± 0.7 cm (p = 0.006). The PRWE score significantly improved from 41.6 ± 22.0 to 15.7 ± 19.5 (p = 0.043). Grip strength was significantly increased from 54.0% ± 14.8%–85.8% ± 18.8% (p = 0.003). The preoperative and postoperative total arc of the wrist and forearm ROM were not significantly different.ConclusionsIntra-articular corrective osteotomy using PMI could be one of the reliable treatment options for intra-articular malunion. PMI has exceptionally high precision performance, and it is also anticipated to yield superior surgical results.     

Posterior clearance increases the knee extension angle in cruciate retaining type total knee arthroplasty: Intraoperative evaluation using a navigation system

BackgroundPosterior osteophyte of the femur can impinge on the tibia insert in total knee arthroplasty (TKA). Although osteophyte removal [posterior clearance (PC)] improves the flexion angle, its influence on the gaps and extension angle are unclear. This study investigated the effect of PC on the gaps and range of motion (ROM) using a navigation system, as well as PC's relationship with osteophyte size.MethodsTwenty-seven knees that underwent cruciate-retaining (CR)-type TKA were examined. Before and after PC, the ROM, hip-knee-ankle (HKA) angle, and flexion and extension gaps were recorded using a navigation system. Osteophyte size was measured in the lateral view in radiographs, and in the sagittal and axial planes of computed tomography (CT) images. The effects of PC on the gaps and ROM were analysed statistically.ResultsPC caused the extension gap to increase by 0.7 ± 0.9 mm in the medial (p < 0.001), and 0.9 ± 1.5 mm in the lateral compartment (p = 0.006). The extension angle increased by 4.9 ± 1.6°, flexion angle increased by 6.5 ± 5.0°, and HKA decreased by 0.3°. The increase in extension angle by PC was significantly correlated with the preoperative HKA angle (r = 0.594) and with the osteophyte area in radiographs and CT (r = 0.626 to 0.681).ConclusionsThe extension and flexion gaps increased less than 1 mm in the medial and lateral compartments. PC achieving an additional 5° extension angle could promote full extension in severely deformed knees with a large posterior osteophyte. The extension angle increase by PC was correlated with the preoperative HKA angle and osteophyte size.     

What happens at the L5/S1 facet joint when implants are placed across the sacroiliac joint?

BackgroundInjuries to the posterior pelvic ring are often stabilized with fixation across the sacroiliac joint (SIJ). However, the compensatory changes at the neighboring L5/S1 facet joint are unknown. The objective of this study was to determine the compensatory change in pelvic kinematics and contact forces at the L5/S1 facet joint after fixation across the sacroiliac joint (SIJ) using a cadaveric model.MethodsFive fresh-frozen cadaveric pelvis specimens were dissected to remove non-structural soft tissue. Retroreflective markers were fixed to the L5 body, S1 body and bilateral anterior superior iliac spines to represent the motion of L5, S1 and the ileum, respectively. Pressure sensors were inserted in both L5/S1 facet joints. Testing was performed using a robotic system that applied load to mimic ambulation. Testing was performed prior to SIJ fixation, after unilateral SIJ fixation and bilateral fixation.ResultsContact force at the L5/S1 facet joint significantly increased by 55% from 48.4 N to 75.2 N following unilateral fixation (p = 0.0161) and increased by 100% to 96.9 N after bilateral fixation (p = 0.0038). Unilateral SIJ fixation increased flexion of the ilium relative to L5 from 1.2° to 2.0° (p = 0.01) and increased axial rotation of L5 relative to S1 from 0.7° to 1.6° (p = 0.001). Bilateral fixation increased flexion of the ilium relative to L5 to 2.0° from 1.2° prior to fixation (p = 0.001), increased axial rotation of L5 relative to S1 to 1.2° from 0.7° prior to fixation (p = 0.002) and increased flexion of L5 relative to S1 to 2.4° from 1.5° prior to fixation (p = 0.04).ConclusionThe L5/S1 facet joint experiences compensatory increased motion under increased contact force after unilateral and bilateral SIJ fixation, possibly predisposing it to adjacent segment arthritis.Level of EvidenceV, cadaveric study     

Correlation of parameters on preoperative CT images with intra-articular soft-tissue injuries in acute tibial plateau fractures: A review of 132 patients receiving ARIF

IntroductionTibial plateau fractures often occur in conjunction with soft-tissue injuries of knees. The hypothesis of this study is that parameters of CT imaging can predict intra-articular soft-tissue injuries.Patients and methodsPatients who underwent arthroscopically assisted reduction and internal fixation (ARIF) for acute tibial plateau fractures performed by a single orthopedic surgeon between 2005 and 2015 were included in this retrospective study. Patients with concomitant ipsilateral femoral fractures, who had received revision surgery or who had undergone index surgery more than 30 days from the event were excluded. We measured lateral plateau depression and widening, medial plateau depression and displacement, and column involvement observed on preoperative CT scans. Intra-articular soft-tissue injuries were diagnosed based on findings from knee arthroscopy. The correlation of imaging parameters with soft-tissue injuries was analyzed by the area under a receiver operating characteristic (AUROC) curve and multivariate logistic regression.ResultsOne-hundred and thirty-two patients were enrolled in the study. The average age was 45.7 ± 13.1 years (range: 18–75 years). Lateral tibial plateau depressions >11 mm were significantly associated with increased risk of lateral meniscus tears (p = 0.001). However, there was no significant threshold of lateral tibial plateau widening that could be used to predict lateral meniscus tear. Greater risk of anterior cruciate ligament (ACL) avulsion fracture was observed in younger patients, patients with high-energy-pattern tibial plateau fractures, patients with fractures involving anteromedial or posterolateral columns, and patients with medial tibial plateau displacement >3 mm (p < 0.05).ConclusionMeasuring lateral tibial plateau depression and column involvement on preoperative CT scans can help predict a higher risk of lateral meniscus tear and ACL avulsion fracture respectively in patients with acute tibial plateau fractures.     

Predictors of osteoarthritis following operative treatment of medial tibial plateau fractures

PurposeTo determine factors influencing the development of posttraumatic osteoarthritis (OA) following medial tibial plateau fractures and to evaluate concomitant injuries associated with these fractures.Materials and methodsA chart review of patients with operatively treated medial tibial plateau fractures admitted to our Level I trauma centre from 2002 to 2008 was performed. Of 63 patients, 41 participated in a clinical and radiographic examination. The mean age was 47 years (range 16–78) and the mean follow-up time was 7.6 (range 4.7–11.7) years. All patients had preoperative computed tomography (CT) scans and postoperative radiographs. At the end of follow-up, standing radiographs, mechanical axis, and CT scans were evaluated.ResultsOf the 41 patients, 24 had no or mild (Kellgren-Lawrence grade 0–2) OA and 17 had severe (grade 3–4) OA. Initial articular depression measured from preoperative CT scans was a significant predictor of OA (median 1.8 mm vs 4.5 mm, p = 0.009). Fracture line extension to the lateral plateau (p = 0.68) or fracture comminution (p = 0.21) had no effect on the development of posttraumatic OA, nor did articular depression at the end of follow-up (p = 0.68) measured from CT scans. Mechanical axis >4° of varus and ≥2 mm articular depression or step-off were associated with worse WOMAC pain scores, but did not affect other functional outcome scores. Six patients (10%) had permanent peroneal nerve dysfunction. Ten patients (16%) required LCL reconstruction and nine (14%) ACL avulsions were treated at the time of fracture stabilisation.ConclusionsThe amount of articular depression measured from preoperative CT scans seems to predict the development of posttraumatic OA, probably reflecting the severity of chondral injury at the time of fracture. Restoration of mechanical axis and articular congruence are important in achieving a good clinical outcome.     

Effects of the tibial tunnel position on knee joint stability and meniscal contact pressure after double-bundle anterior cruciate ligament reconstruction

BackgroundTo investigate the effect of the tibial tunnel position on knee stability and the maximum contact area and peak contact pressure on the menisci after double-bundle anterior cruciate ligament (ACL) reconstruction.MethodsTen human knee specimens (mean age: 74.1 ± 15.8 years) were used in this study. The anterior tibial loading test was conducted using a material testing machine at 30°, 60°, and 90° of knee flexion, with the anterior tibial translation (ATT) and the maximum contact area and peak contact pressure on the menisci measured. Outcome measures were compared between the following groups: 1) intact ACL (intact group); 2) anatomical tibial tunnel position (anatomical group) and 3) posterior tibial tunnel position (posterior group) with double-bundle reconstruction, and 4) ACL-deficient (deficient group).ResultsIn response to a 100 N anterior tibial load, the ATT was greater for the posterior and ACL-deficient groups compared to that in the intact group. The normalized maximum contact area of the medial meniscus significantly decreased for the posterior group compared to that in the intact group. The normalized peak contact pressure on the medial meniscus increased in all groups compared to that in the intact group, but with no between-group differences in pressure applied to the lateral meniscus.ConclusionsATT and contact pressure on the medial meniscus increased, concomitant with a decrease in contact area of the medial meniscus, as the position of the tibial tunnel position moved towards a posterior position.     

A combined approach for the treatment of lateral and posterolateral tibial plateau fractures

IntroductionThe treatment of tibial plateau fractures involving the lateral and posterolateral column is a demanding and fine surgical challenge. The purpose of this study was to evaluate the safety and clinical efficacy of combined approach for the treatment of lateral and posterolateral tibial plateau fractures.MethodsA prospective study was performed in 17 patients with lateral and posterolateral tibial plateau fractures between January 2009 and December 2012. There were 12 males and 5 females with a mean age of 40 years. All of them received dual-plate fixation through the combined approach, with the patients in a floating position. The combined approaches included a conventional anterolateral approach and an inverted L-shaped posterolateral approach. Operation time, intraoperative blood loss, fracture healing time, Hospital for Special Surgery (HSS) knee score, knee flexion and extension range of motion, and complications were recorded to evaluate treatment effects.ResultsThere were no intraoperative complications related to this technology. Mean operation time was 144 min with a mean intraoperative blood loss volume of 233 mL. The mean follow-up was 23 months. All 17 patients had good postoperative fracture healing. Mean union time was 12 weeks. At the final follow-up, the average HSS score was 92.5, with the average knee flexion of 125° and an average knee extension of 2°. Two patients had complications in postoperative incisions with aseptic fat liquefaction. After thorough debridement, second-stage wounds healing were achieved. No neurovascular injury occurred. No collapse of reduced articular surface was detected.ConclusionsThe combined approach with dual-plate offers direct and complete surgical exposure and provide an effective method for the treatment of lateral and posterolateral tibial plateau fractures.     

全膝关节置换术后股胫关节运动学轨迹的数字化模型研究

 目的 通过透视技术结合数字化模型注册技术分析全膝关节置换术后股骨假体与胫骨垫片之间的相对运动和接触位置。方法 2007年7月至2008年6月,接受GENESISⅡ假体全膝关节置换术患者16例,均为女性;年龄56～76岁,平均66.4岁。随访48～60个月,平均(56±3)个月。采用膝关节学会评分(Knee Society Score,KSS)评价膝关节功能;采用循环透视方法获取影像学数据,对假体逆向数字建模,进行数字模型和影像学数据的匹配,重建膝关节的三维运动;测量股骨内、外髁接触位置的移动,计算胫骨内旋角度,测量股骨凸轮和胫骨立柱的接触时相和范围。结果 末次随访时KSS膝评分(93±5)分,功能评分(88±13)分,与术前比较差异有统计学意义。股骨内髁的移动范围(8.5±2.5) mm,外髁的移动范围(9.5±4.8) mm,胫骨内旋角度2.5°±8.4°。屈膝约30°～40°时凸轮和立柱发生接触,立柱后方的接触范围(8.0±1.8) mm。胫骨平台后倾角度越大,凸轮和立柱的接触越晚。结论 全膝关节置换术后股胫关节的运动学特征与正常膝关节不同,膝关节屈曲10°~30°时股骨内髁前移,屈曲大于40°后股骨内、外髁后移,胫骨平台后倾与凸轮和立柱的接触时相有相关性。