Periarticular locking plate vs intramedullary nail for tibiotalocalcaneal arthrodesis: a biomechanical investigation

Augmented retrograde intramedullary (IM) nail fixation was compared with augmented periarticular locking- plate fixation for tibiotalocalcaneal arthrodesis. Specimens in 10 matched pairs were randomly assigned to a fixation construct and loaded cyclically in dorsiflexion. The groups did not differ in initial or final stiffness, load to failure, or construct deformation. No correlation was found between bone mineral density and construct deformation for either group. A humeral locking plate may be a viable alternative to an IM nail for tibiotalocalcaneal fixation in cases not amenable to IM nailing.     

Biomechanical analysis of screw-augmented intramedullary fixation for tibiotalocalcaneal arthrodesis

BACKGROUND: This study compared intramedullary (IM) fixation for tibiotalocalcaneal arthrodesis with and without a tibiotalocalcaneal augmentation screw. METHODS: Each specimen in six matched pairs of fresh frozen cadavers underwent tibiotalocalcaneal arthrodesis with an IM nail. One specimen from each pair also received a tibiotalocalcaneal augmentation screw. Initial and final stiffness, load to failure, and construct deformation at failure were calculated with dorsiflexion loading. Bone mineral density of each pair was determined. Statistical analysis was done using a paired Student t-test and a Pearson correlation. RESULTS: Initial and final stiffness and load to failure were significantly higher for the tibiotalocalcaneal screw augmented fixation group as compared with the specimens with no additional screw (initial stiffness, 128.0 versus 78.4 N/mm, p = 0.04; final stiffness, 230.9 versus 164.7 N/mm, p = 0.04; load to failure, 875.5 versus 660.2 N, p = 0.03). There was a significant negative correlation between bone mineral density and average construct deformation in the samples without the added tibiotalocalcaneal screw (r = -0.90, p = 0.02). CONCLUSIONS: In tibiotalocalcaneal arthrodesis with intramedullary nail fixation, a tibiotalocalcaneal augmentation screw provides more stable fixation. CLINICAL RELEVANCE: Use of an augmentation screw as described in this study may lead to lower complication rates, particularly in patients with osteopenic bone.     

A biomechanical comparison of micromotion after ankle fusion using 2 fixation techniques: intramedullary arthrodesis nail or Ilizarov external fixator

BACKGROUND: In difficult ankle arthrodesis situations, intramedullary (IM) arthrodesis nails and external fixation are often considered in lieu of standard fusion techniques. The purpose of this study was to compare the amount of micromotion measured across an ankle fusion site stabilized with either an IM nail or with the Ilizarov external fixator. MATERIALS AND METHODS: The relative bone mineral density of 8 pairs of human cadaveric lower legs was measured by DEXA scanning. One specimen from each pair was randomly assigned to be stabilized with a new generation IM nail and the other with an Ilizarov external fixator. Specimens were tested in compression, rotation, and dorsiflexion. Optical motion capture was used to measure the direct motion occurring at the fusion site. RESULTS: No significant difference was found between the axial displacements (p = 0.94), torsional displacement (p = 0.07), or the dorsiflexion angular displacement (p = 0.28) for the IM rod group and the external fixation group. A weak correlation was found between BMD and displacement. CONCLUSION: Both the new generation IM nail and the Ilizarov external fixator imparted excellent stability to the fusion site despite a wide range of bone mineral densities. Medialization of the talus, the ability to compress the nail, and the addition of a posterior-to-anterior locking screw were thought to improve the performance of the nail. CLINICAL RELEVANCE: Both IM nail and Ilizarov external fixation provided excellent fusion site stability. The decision of which implant to use for complex arthrodesis should be dictated by the clinical needs.     

Intramedullary nail fixation with posterior-to-anterior compared to transverse distal screw placement for tibiotalocalcaneal arthrodesis: a biomechanical investigation

BACKGROUND: Biomechanical studies on retrograde intramedullary fixation for tibiotalocalcaneal fusion have been reported, but no studies have investigated dorsiflexion stiffness, load-to-failure, fatigue endurance, and plastic deformation using different distal screw orientations. Also, no studies have examined the effect of bone density on different distal screw orientations while using a fatigue loading mode. METHODS: Eight matched pairs of cadaver legs were used. In one leg from each pair an intramedullary nail was inserted with lateral-to-medial distal screws and in the other with posterior-to-anterior screws. These samples underwent dorsiflexion fatigue testing with determination of initial and final stiffness, load-to-failure, and degree of plastic deformation at failure. DEXA scanning was done of each cadaver specimen to determine bone mineral density. Statistical analysis was performed using the Student t-test and a Pearson correlation. Significance level was set at p < 0.05. RESULTS: The specimens with posterior-to-anterior screws had a significantly higher fatigue endurance load-to-failure (1130.0 +/- 362.0 N compared to 801.0 +/- 227 N, p = 0.01). They also had significantly higher final stiffness (203.1 +/- 23.1 N/mm compared to 146.6 +/- 46.2 N/mm, p = 0.05) and lower plastic deformation (2.4 +/- 1.5 mm compared to 3.8 +/- 2.3 mm, p = 0.04). There was a statistically significant correlation between bone mineral density and the difference in construct deformation with posterior-to-anterior and lateral-to-medial screw orientation (r = 0.76, p = 0.03). CONCLUSIONS: In this biomechanical investigation of tibiotalocalcaneal arthrodesis with intramedullary nail fixation, posterior-to-anterior distal screw orientation provided more stable fixation than lateral-to-medial screw orientation.     

肱骨干骨折髓内外固定的生物力学研究

目的 通过对单一加压钢板螺钉加髓内针、交锁髓内钉和微创技术简单有限内固定加单臂外支架3种不同固定方法治疗肱骨干复杂骨折的生物力学性能进行对比研究,为临床应用提供可靠的生物力学依据.方法 取自愿捐赠的18个新鲜湿润肱骨标本,制备肱骨干复杂骨折模型,根据不同固定方式随机分为3组,每组6个.钢板组:采用单一加压钢板螺钉加髓内针固定;髓内钉组:采用交锁髓内钉固定;外支架组:采用微创技术简单有限内固定加单臂外支架固定.分别进行轴向压缩实验和水平扭转实验.结果 轴向压缩实验:各组载荷-位移曲线呈线性到非线性变化.钢板组及髓内钉组最大载荷值分别为(6162.09±521.06)N和(6738.32±525.89)N,两组比较差异无统计学意义(P>0.05);外支架组最大载荷值为(2753.57±185.59)N,与其余两组比较,差异均有统计学意义(P<0.05).钢板组及外支架组刚度值分别为(171.69±6.49)N/mm和(132.59±2.93)N/mm,两组比较差异无统计学意义(P>0.05);髓内钉组的刚度值为(333.04±36.85)N/mm,与其余两组比较差异有统计学意义(P<0.05).水平扭转实验:各组扭矩-扭角曲线呈线性到非线性变化.髓内钉组和外支架组的最大扭矩分别为(17.12±5.73)Nm和(20.26±6.42)Nm,两组比较差异无统计学意义(P>0.05);钢板组的最大扭矩为(38.24±7.08)Nm,与其余两组比较差异有统计学意义(P<0.05).钢板组及外支架组刚度值分别为(16.36±2.07)Ncm/°和(18.79±2.62)Ncm/°,差异无统计学意义(P>0.05);髓内钉组的刚度值为(11.45±0.22)Ncm/°,与其余两组比较差异有统计学意义(P<0.05).结论 钢板组压缩和扭转强度均较强,旋转刚度较强而压缩刚度较弱;髓内钉组压缩强度和压缩刚度较强,而扭转强度和扭转刚度较弱;外支架组仅在扭转刚度上与钢板组相当,而在其他3项指标上均较弱.     

Blade plate compared with locking plate for tibiotalocalcaneal arthrodesis: a cadaver study.

BACKGROUND: We hypothesized that a locking plate would be stronger than a blade plate for tibiotalocalcaneal arthrodesis under dorsiflexion and torsional loading. MATERIALS AND METHODS: Nine pairs of matched cadaveric lower extremities were used. BMD was obtained for each specimen. Each received a retrograde augmentation screw and a stainless steel LC-angled blade plate (Synthes, Paoli, PA) or a stainless steel LCP proximal humerus locking plate (Synthes, Paoli, PA). Specimens were cyclically loaded in dorsiflexion to simulate 6 weeks of partial weightbearing and then monotonically loaded to failure. Specimens were removed from the load frame and remounted to simulate fusion. The specimen received an axial load of 720 N and was externally rotated proximal to the construct at 5 degrees/sec to fracture. Data were compared with a Student's t-test. Pearson correlation analysis was used to determine whether bone mineral density was significantly related to measured parameters. Significance was set at p < or = 0.05. RESULTS: The locking plate group had higher initial stiffness, higher dorsiflexion and torsional load to failure, and lower construct deformation than the blade plate group. Bone mineral density was positively correlated with dorsiflexion failure load and torsional failure load in the locking plate construct. CONCLUSION: Fixation with the locking plate was superior to that with the blade plate. CLINICAL RELEVANCE: Use of a locking plate may be an effective fixation technique in tibiotalocalcaneal arthrodesis, especially in complex hindfoot reconstructions with bone loss or deformity.     

Biomechanical evaluation of primary stiffness of tibiotalar arthrodesis with an intramedullary compression nail and four other fixation devices

BACKGROUND: Many techniques of tibiotalar arthrodesis have been described. Screw fixation is widely used. At our center, intramedullary compression nailing has been successfully used for over 10 years. The question to be answered by this study was whether tibiotalar arthrodesis with a compressed intramedullary nail was superior, in terms of primary stiffness and fusion-site compression, to selected other techniques. METHODS: Plane fusion surfaces were machined in third-generation synthetic composite tibiae and the bodies of anatomically correct tali; fixation was with a compressed external fixator (cEF), an uncompressed interlocking nail (uIN), a compressed interlocking nail (cIN), and two different three-screw techniques (ST1 and ST2); three specimens per construct were tested. The compressed contact surface of each construct was measured with pressure-sensitive film and expressed as a percent of the available fusion-site area. Construct stiffness was tested in dorsiflexion/plantar flexion (D/P), varus/valgus (V/V), and internal rotation/external rotation (I/E), analyzing 20 cycles per loading mode. RESULTS: Compressed surface area: cIN 80% +/- 10.7; cEF 60% +/- 8.6; ST2 59% +/- 4.4; ST1 55% +/- 6.1; uIN no discernible compression. The greatest primary stiffness in D/P was obtained with the cIN (p < 0.001), followed by ST1. In V/V, ST1 and the cIN had the greatest primary stiffness; the two techniques did not differ significantly. Stabilization with the cEF was significantly better (p < 0.001) than with ST2. In I/E, the cIN produced the greatest primary stiffness (p < 0.001), followed by the two screw techniques, which did not differ significantly between themselves. The uIN had the least primary stiffness in all directions tested. CONCLUSIONS: In this biomechanical study, the cIN and ST1 were superior, in terms of primary stiffness in tibiotalar arthrodesis, to the other techniques tested. In D/P and I/E, the cIN construct was significantly stiffer than the ST1 construct, whose I/E rigidity might, however, be enhanced by a fourth, horizontal screw. CLINICAL RELEVANCE: Intramedullary compression nailing offers stable tibiotalar arthrodesis fixation with a large bony contact area and may enhance the likelihood of successful tibiotalar arthrodesis.     

Crossed screws versus dorsomedial locking plate with compression screw for first metatarsocuneiform arthrodesis: a cadaver study

BACKGROUND: We hypothesized that a dorsomedial locking plate with adjunct screw compression would provide superior rigidity compared to crossed screws for first metatarsocuneiform (MTC) arthrodesis. MATERIALS AND METHODS: In ten matched lower extremity pairs, specimens in each pair were randomly assigned to receive screw fixation or plate with screw fixation. Bone mineral density (BMD) was measured. For the crossed-screw construct, two 4.0-mm cannulated screws were used. One screw was inserted dorsal to plantar beginning from the first metatarsal 10 to 15 mm distal to the joint, and the second was inserted from the cuneiform 8 to10 mm proximal to the joint, medial to the first screw, into the first metatarsal. For the plate construct, a 4.0-mm cannulated compression screw was inserted from the dorsal cortex of the first metatarsal to the plantar aspect of the medial cuneiform. A locking plate was inserted dorsomedially across the MTC joint. Specimens were loaded in four-point bend configuration (displacement rate, 5 mm/min) until failure of the fixation or 3-mm deformation. An extensometer was used to measure deformation. RESULTS: There was no difference in load to failure or stiffness between the two groups. BMD was positively correlated with load to failure in the screw (r = 0.893, p = 0.001) and the plate (r = 0.858, p = 0.001) construct. CONCLUSION: The plate construct with compression screw did not show different rigidity as compared with the screw construct with the numbers available. CLINICAL RELEVANCE: Further investigation of a dorsomedial plate with adjunct screw compression may be warranted for first MTC arthrodesis.     

Tibiotalocalcaneal arthrodesis: a biomechanical assessment of stability

BACKGROUND: Combined ankle and subtalar (tibiotalocalcaneal) arthrodesis is a procedure that can be used to successfully treat disabling foot and ankle arthropathy and is a reasonable salvage alternative to amputation for the treatment of nonbraceable neuropathic, diabetic, degenerative, or rheumatoid joints. Although many methods of tibiotalocalcaneal (TTC) arthrodesis have been described in the literature, the most popular current methods involve the use of crossed cancellous bone screws, plates, or a locked retrograde intramedullary rod. Fusion in these patients can be difficult, with significant complications including infection, malunion, and nonunion. A persistent nonunion can lead to failure of the hardware and recurrent deformity. METHODS: We biomechanically tested the stability and micromotion in four methods of TTC arthrodesis using liquid metal strain gauges and Instron (Norwood, MA) material testing systems. Anatomically identical synthetic bones with properties very similar to human bone were instrumented and tested. Four instrumentation techniques were tested: 1) three crossed 6.5-mm cancellous screws, 2) two crossed 6.5-mm cancellous screws, 3) locked retrograde intramedullary rod, and 4) locked retrograde intramedullary rod augmented with a single anteromedial bone staple. Six separate specimens for each technique were tested. RESULTS: The three crossed cancellous screw technique provided the greatest stability with respect to micromotion (p < 0.05). The addition of a tibiotalar staple to the locked intramedullary rod conferred stability nearly equal to that of the three crossed cancellous screw fixation (p < 0.05). The locked intramedullary rod group and the two crossed cancellous screw group allowed significant micromotion at the arthrodesis sites, which was a full order of magnitude higher (p < 0.05) than in the three crossed cancellous screw group and the staple augmented intramedullary rod group. CONCLUSIONS: Biomechanically, a staple augmented locked intramedullary rod for TTC arthrodesis confers excellent stability nearly equal to the three crossed cancellous screw technique for TTC arthrodesis.     

Biomechanical evaluation of primary stiffness of tibiotalocalcaneal fusion with intramedullary nails

BACKGROUND: Intramedullary implants are being used with increasing frequency for tibiotalocalcaneal fusion (TTCF). Clinically, the question arises whether intramedullary (IM) nails should have a compression mode to enhance biomechanical stiffness and fusion-site compression. This biomechanical study compared the primary stability of TTCF constructs using compressed and uncompressed retrograde IM nails and a screw technique in a bone model. METHODS: For each technique, three composite bone models were used. The implants were a Biomet nail (static locking mode and compressed mode), a T2 femoral nail (compressed mode); a prototype IM nail 1 (PT1, compressed mode), a prototype IM nail 2 (PT2, dynamic locking mode and compressed mode), and a three-screw construct. The compressed contact surface of each construct was measured with pressure-sensitive film and expressed as percent of the available fusion-site area. Stiffness was tested in dorsiflexion and plantarflexion (D/P), varus and valgus (V/V), and internal rotation and external rotation (I/E) (20 load cycles per loading mode). RESULTS: Mean contact surfaces were 84.0 +/- 6.0% for the Biomet nail, 84.0 +/- 13.0% for the T2 nail, 70.0 +/- 7.2% for the PTI nail, and 83.5 +/- 5.5% for the compressed PT2 nail. The greatest primary stiffness in D/P was obtained with the compressed PT2, followed by the compressed Biomet nail. The dynamically locked PT2 produced the least primary stiffness. In V/V, PT1 had the (significantly) greatest primary stiffness, followed by the compressed PT2. The statically locked Biomet nail and the dynamically locked PT2 had the least primary stiffness in V/V. In I/E, the compressed PT2 had the greatest primary stiffness, followed by the PT1 and the T2 nails, which did not differ significantly from each other. The dynamically locked PT2 produced the least primary stiffness. The screw construct's contact surface and stiffness were intermediate. CONCLUSIONS: The IM nails with compression used for TTCF produced good contact surfaces and primary stiffness. They were significantly superior in these respects to the uncompressed nails and the screw construct. The large contact surfaces and great primary stiffness provided by the IM nails in a bone model may translate into improved union rates in patients who have TTCF.     

4种内固定方法治疗锁骨中段骨折疗效比较

目的比较不同内固定方法治疗锁骨中段骨折的疗效。方法应用重建锁定钢板、锁定解剖钢板、Herbert中空螺钉和交锁髓内钉4种内固定方法治疗111例锁骨中段骨折患者。比较4种手术方法的手术时间、切口长度、术中出血量、骨折愈合时间及肩关节功能。结果患者均获得随访,时间12~18个月。手术时间:重建锁定钢板组长于锁定解剖钢板组、Herbert中空螺钉组和交锁髓内钉组,差异有统计学意义(P0.05)。术中出血量:重建锁定钢板组和锁定解剖钢板组多于Herbert中空螺钉组和交锁髓内钉组,差异有统计学意义(P0.05)。切口长度:重建锁定钢板组和锁定解剖钢板组长于Herbert中空螺钉组和交锁髓内钉组,差异有统计学意义(P0.05)。骨折愈合时间:重建锁定钢板长于锁定解剖钢板组、Herbert中空螺钉组和交锁髓内钉组,差异有统计学意义(P0.05)。4种手术方法肩关节功能JOA评分比较差异无统计学意义(P0.05)。并发症:重建锁定钢板组、锁定解剖钢板组各有2例钢板断裂,Herbert中空螺钉组2例退钉,交锁髓内钉组无并发症发生。结论 4种固定方法治疗锁骨中段骨折均取得满意疗效,Herbert中空螺钉和交锁髓内钉固定治疗锁骨中段骨折较重建锁定钢板和锁定解剖钢板固定更符合生物力学特性,更具合理性。     

Biomechanical comparison of intramedullary nail and blade plate fixation for tibiotalocalcaneal arthrodesis

OBJECTIVE: Tibiotalocalcaneal arthrodesis is used to manage severe bone loss, arthritis, and/or instability. The goal is to relieve pain through a stable, well-aligned hindfoot and ankle. The purpose of this study was 2-fold: to biomechanically compare 1) initial stability, and 2) the effect of bone density on the stability of intramedullary nail and blade plate fixation in tibiotalocalcaneal arthrodesis. DESIGN: Biomechanical study using anatomic specimens. METHODS: Ankle and subtalar joint capsules were exposed for 7 pairs of fresh-frozen anatomic specimens. One ankle from each pair was instrumented with an interlocked intramedullary nail inserted retrograde across the subtalar and ankle joint while the contralateral hind foot was stabilized with a lateral cannulated blade plate. Specimen stability was tested in plantar/dorsiflexion and inversion/eversion to a maximum bending moment of 12 Nm and in internal/external rotation to a maximum torque of 7 Nm. Physical measurements of bone density were made to determine its effect on stability. MAIN OUTCOME MEASURES: Maximum angular displacement of the constructs in plantarflexion, dorsiflexion, inversion, eversion, internal rotation, and external rotation. RESULTS: No significant differences were observed between the plated and nailed constructs in the 3 loading configurations (Power = 0.77). Only 6 pairs were included in the results because of fixation failures. A small but significant reduction in internal rotation alone of 1.8 degrees was found with the plated compared with the nailed construct (P = 0.045). Reduced stability was associated with lower bone density in torsion and inversion/eversion in the plated constructs (r = 0.67- 0.87) with a similar trend seen in torsion in the nailed constructs (r = 0.5). CONCLUSION: Initial construct stabilities and the effect of reduced bone density were found to be similar between the blade plate and the intramedullary nail in tibiotalocalcaneal arthrodesis, thus implant choice may be based on other clinical factors, such as surgeon preference or soft-tissue status.     

Tibiotalocalcaneal arthrodesis: a biomechanical comparision of multiplanar external fixation with intramedullary fixation

BACKGROUND: Methods of achieving tibiotalocalcaneal arthrodesis include intramedullary nailing, crossed lag screws, blade plates, and external fixation. While reports in the orthopaedic literature have compared the biomechanical properties of some of these fixation techniques, to our knowledge none has evaluated multiplanar external fixation. The purpose of this study was to compare the biomechanical properties of intramedullary nail fixation and external ring fixation for tibiotalocalcaneal arthrodesis. MATERIALS AND METHODS: Tibiotalocalcaneal arthrodesis was performed on ten matched pairs of fresh-frozen human cadaveric legs. A ring fixator stabilized the arthrodesis in one leg from each pair and a 10 mm x 150 mm nail inserted retrograde across the subtalar and ankle joint stabilized the arthrodesis in the contralateral leg. The bending stiffness of the resulting constructs was quantified in plantarflexion, dorsiflexion, inversion, and eversion, and torsional stiffness was measured in internal and external rotation. RESULTS: No difference in bending stiffness between the two constructs was identifiable in any of the four bending directions (p > 0.05). Torsional stiffness was approximately two-fold greater in both internal and external rotation in specimens with the ring fixator arthrodesis than in those with the intramedullary nail (p = 0.002). CONCLUSION: The ring fixator provides a stiffer construct than a 10 mm x 150 mm intramedullary nail in torsion, but no difference in bending stiffness was demonstrable. Both techniques can provide satisfactory fixation; however, the ring fixator may better minimize rotational joint motion. CLINICAL RELEVANCE: This study provides a basis for selecting an arthrodesis method that offers optimized fixation.     

Biomechanical Comparison of a Locking Plate with Intraplate Compression Screw Versus Locking Plate with Plantar Interfragmentary Screw for Lapidus Arthrodesis: A Cadaveric Study

Lapidus arthrodesis (first metatarsal cuneiform arthrodesis) has become an accepted procedure for hallux abducto valgus. Several variations of fixation have been described. Earlier weightbearing postoperatively has been one reported benefit of using locking plates for fixation. Additionally, studies have demonstrated that fixation placed on the plantar or tension side of the arthrodesis increases the biomechanical advantage. We performed a biomechanical cadaveric study of the Lapidus procedure, comparing a previously reported technique using a low profile locking plate with an intraplate compression screw versus the same locking plate with a plantar interfragmentary screw (PIFS) placed on the tension side of the arthrodesis in 10 fresh, paired, cadaver limbs. The mean ultimate load of the plate with a PIFS was 383.2 ± 211.5 N, and the mean ultimate load of the plate with an intraplate compression screw was 205.5 ± 97.2 N. The mean ultimate load of the LPS Lapidus plate with a PIFS was statistically greater (p = .027) than that with the plate intraplate compression screw. Our results indicated that changing the orientation of the compression screw to a PIFS significantly increased the stability of the Lapidus arthrodesis fixation construct. The modified construct with the PIFS might decrease the incidence of nonunion and, ultimately, allow patients to bear weight faster postoperatively.     

The modified use of a proximal humeral locking plate for tibiotalocalcaneal arthrodesis

BACKGROUND: Different types of fixation have been used to achieve a tibiotalocalcaneal (TTC) arthrodesis. The purpose of this study was to retrospectively examine the modified use of a 3.5-mm proximal humeral locking plate (PHILOS plate, Synthes, Paoli, PA) in obtaining a TTC fusion. METHODS: Between April, 2003, and November, 2005, 17 patients had 18 TTC arthrodeses with a PHILOS plate through a transfibular approach. Preoperative diagnoses included Charcot arthropathy, neuromuscular disease, arthritis, and talar osteonecrosis. Patients were followed from 8 months to 3 years and 2 months (mean 20.6 months). RESULTS: Fusion was achieved in 16 of the 17 patients (94.1%) and 17 of the 18 arthrodeses (94.4%) with a mean time to fusion of 20.6 weeks. The mean American Orthopaedic Foot and Ankle Society (AOFAS) score increased from 14.6 of 100 preoperatively to 76.7 of 86 (equivocal to 89.2 of 100) at final followup. One patient who had brittle diabetes went on to develop a nonunion. CONCLUSIONS: The patients in this study had a wide variety of medical conditions that left their bone osteopenic or osteoporotic. This study demonstrated that using a modified locking plate for a TTC arthrodesis results in a high rate of bony union and alignment correction stability. The locking plate provides fixation by acting as a fixed angle device, with the locking screws providing multiplanar fixation. The use of a locking plate has not been previously reported, and it may hold promise as a means of achieving a TTC fusion.     

Screw fixation compared to H-locking plate fixation for first metatarsocuneiform arthrodesis: a biomechanical study

BACKGROUND: Several different techniques have been used for fixation of first metatarsocuneiform (MTC) joint arthrodesis, a standard treatment for arthritis, instability, and deformity of the MTC joint. Improved plating systems using locking designs are now available, but no studies have yet compared this construct with other methods. We compared load to failure with a locking plate design versus standard crossed-screw fixation. METHODS: Ten matched pairs of fresh frozen cadaver feet were used. The bone density of each pair was measured with DEXA scanning. One foot of each pair was randomly assigned to have a dorsomedial Normed H titanium locking plate (Normed Medizin-Technik Vertriebs-GmbH, D-78501 Tuttlingen, Germany) applied to the first MTC joint. On the other foot of the pair, fixation of the first MTC joint was done with crossed ACE DePuy 4.0 (DePuy/Ace, Warsaw, IN) titanium cannulated screws. The first metatarsal and first cuneiform were then isolated and planted in an epoxy resin. The specimens were loaded to failure in a four-point bending configuration using a MTS Mini Bionix test frame (MTS Systems Corp., Eden Prairie, MN). Failure was defined as displacement of more than 3 mm at the arthrodesis site. The Student t-test was used to determine any observed differences, with significance set at p 相似文献   

First Tarsometatarsal Joint Fusion for Hallux Valgus Deformity: A Retrospective Comparison of Two Fixation Constructs Regarding Initial Maintenance of Correction and Complications: Traditional Crossing Screw Fixation Versus Dorsomedial Locking Plate and Intercuneiform Compression Screw

Various fixation constructs exist to address hallux valgus when performing a first tarsometatarsal joint arthrodesis. The goal of this present study is to compare complication rates, and degree and maintenance of angular correction between a dorsomedial locking plate with intercuneiform compression screw construct versus traditional crossing solid screw fixation construct. The plate plus intercuneiform compression screw construct fixation utilized a combined sagittal saw and curette method of joint preparation while the crossed screw fixation group utilized a curette and bur technique. A retrospective review was conducted of consecutive patients who underwent a midfoot fusion using either constructs. Sixty four total feet in 56 patients were enrolled in the study. Twenty four consecutive patients (32 feet) who underwent a midfoot arthrodesis using the locking plate and intercuneiform fixation were fully fused (100%) by 10 weeks postoperatively, with no incidents of nonunion and one deep vein thrombosis event. Thirty two consecutive patients (32 feet) who underwent midfoot arthrodesis with crossing screw fixation had 2 nonunion events, one that was asymptomatic and the other that required a revision midfoot fusion. There was a statistically significant improvement from the pre-operative intermetatarsal angle, hallux abductus angle compared to the 10 week and 1 year radiographs (p < .05) for the entire cohort for both fixation constructs. There was a statistically significant increase in American College of Foot and Ankle Surgery first ray scores from pre-op to 1 year follow-up for both fixation constructs. Overall, the dorsomedial locking plate plus intercuneiform compression screw fixation construct better maintains Intermetatarsal angle (IMA) correction at midterm follow-up compared to the traditional crossing screw construct. Both cohorts overall demonstrate similar fusion rates at 10 weeks, nonunion events, incidences of broken hardware, hardware removal, deep vein thrombosis, neuritis at 1 year postoperatively, and hallux varus.     

Modern Retrograde Intramedullary Nails Versus Periarticular Locked Plates for Supracondylar Femur Fractures After Total Knee Arthroplasty

This study purpose is to analyze outcomes of modern intramedullary (IM) nails with a locked distal screw versus periarticular locking plates for peri-prosthetic supracondylar femur fractures in TKA. Ninety-five consecutive fractures in 91 patients were retrospectively reviewed. Fixation included 29 knees with a retrograde IM nail and 66 periarticular locked plates. Six patients died and 4 were lost to follow-up. There were 2 (9%) nonunions in the IM nail group and 12 non-unions/delayed-unions (19%) in the locked plate group (P = 0.34). A mean of 5.0 distal screws was used in locked plates versus 3.8 distal screws in the IM nails (P < 0.001). Despite a greater quantity of screws in the distal fragment, the failure rate of locked plating was twice that of IM nail fixation.     

Fixation of three-part proximal humeral fractures: a biomechanical evaluation

OBJECTIVES: To examine the biomechanical stability of three constructs currently used for the management of three-part proximal humerus fractures. Tension band wires (TBW) with supplemental Enders nails, modified cloverleaf plate and screws, and intramedullary (IM) nailing with proximal and distal interlocks were tested to determine relative stability. DESIGN: A reproducible three-part fracture was made in fresh-frozen stripped proximal humeri. The fracture was stabilized using TBW/Enders nail (n = 6), plate/screws (n = 5), or IM nailing (n = 5). MAIN OUTCOME MEASUREMENTS: Mechanical testing was performed with a small preload followed by deflection of five millimeters at a rate of one millimeter per second in flexion, extension, and varus and valgus relative to the humeral shaft. A load-displacement curve was obtained. Torsional testing was performed in internal and external rotation, and torque-rotation curves were recorded. RESULTS: In cantilever bending, the plate/screws construct and the IM nail construct were superior to the TBW/Enders nail construct for all parameters except extension. There was no statistically significant difference between the IM nail and the plate/screws groups. Torsional stiffness testing revealed that the plate/screws and the IM nail were superior to the TBW/Enders nail construct. There was no statistical difference between the IM nail and the plate/screws groups. CONCLUSIONS: In a cadaveric model of three-part proximal humerus fractures stripped of soft tissue, plate/screws fixation and IM nailing provide greater torsional and bending stiffness than does fixation with TBW/Enders nail. There was no statistically significant difference in torsional or bending stiffness between IM nailing with interlocks and plate/screws fixation in this model.