Penetration of the distal femoral anterior cortex during intramedullary nailing for subtrochanteric fractures: a report of three cases

Three cases of anterior distal femoral cortex penetration during intramedullary nailing for subtrochanteric fractures are documented. Case 1 involved a Zimmer (Warsaw, IN) M/DN antegrade femoral nail, case 2 a Howmedica (Allendale, NJ) long-stem Gamma nail, and case 3 a Synthes (Paoli, PA) titanium femoral nail with spiral blade locking. The anterior Zimmer nail penetration resulted in a displaced supracondylar fracture, which subsequently required revision. The Gamma nail as well as the Synthes nail were left impaled through the distal femoral cortex, and the subtrochanteric fractures went on to union. The anteroposterior radius of curvature for the Zimmer, the long Gamma, and the Synthes nail are 257 cm, 300 cm, and 150 cm, respectively. It has been estimated that the radius of curvature of the femoral diaphyseal canal is 114 to 120 cm. It appears that the difference in femoral anteroposterior bow between the bone and the implant is a contributing factor to distal femoral anterior cortex penetration in intramedullary nailing of subtrochanteric fractures.     

Removal of a broken intramedullary femoral nail with an unusual pattern of breakage: a case report

To the best of our knowledge, only 3 cases, including the present case, have been reported with a three part broken pattern. However, this is the first case associated with a distal locking screw broken. We report the case of a 31-year-old patient who sustained an open femoral shaft fracture . The fracture was stabilized with a Kuntcher femoral nail. After 7 months of the initial surgery he presented with a three part broken intramedullary nail and the distal locking screw broken. We used a combined technique for the removal of the nail through the nonunion fracture site; we used a pull out technique for the middle fragment and a curved thin hook for the distal fragment. Then we applied bone allograft and stabilized with a cannulated intramedullary femoral nail (Synthes, Oberdorf, Switzerland). After 2 years of follow up the nonunion was consolidated and the patient presented a good clinical outcome. This is of particular interest because it is a unique case and the association with a broken distal locking screw is reported for the first time in this study. A combination of methods through the nonunion site approach and an alternative instrumental is a good method for the removal of a hollow femoral intramedullary nail with this unusual pattern of breakage.     

Working length and proximal screw constructs in plate osteosynthesis of distal femur fractures

BackgroundThe study purpose is to evaluate the working length, proximal screw density, and diaphyseal fixation mode and the correlation to fracture union after locking plate osteosynthesis of distal femoral fractures using bridge-plating technique.MethodsA four-year retrospective review was performed to identify patients undergoing operative fixation of distal femur fractures with a distal femoral locking plate using bridge-plating technique for the metadiaphyseal region. Primary variables included fracture union, secondary surgery for union, plate working length, and diaphyseal screw technique and configuration. Multiple secondary variables including plate metallurgy and coronal plane fracture alignment were also collected.ResultsNinety-six patients with distal femur fractures with a mean age 60 years met inclusion criteria. None of the clinical parameters were statistically significant indicators of union. Likewise, none of the following surgical technique parameters were associated with fracture union: plate metallurgy, the mean working length, screw density and number of proximal screws and screw cortices. However, diaphyseal screw technique did show statistical significance. Hybrid technique had a statistically significant higher chance of union when compared to locking (p = 0.02). All proximal locking screw constructs were 2.9 times more likely to lead to nonunion.ConclusionsPlating constructs with all locking screws used in the diaphysis when bridge-plating distal femur locking plates were 2.9 times more likely to incur a nonunion. However, other factors associated with more flexible fixation constructs such as increased working length, decreased proximal screw number, and decreased proximal screw density were not significantly associated with union in this study.     

Prevention of potential fracture between two implants using interlocking bipolar cut short GK nail and Enders nail

A technique to prevent a potential fracture occurring between the distal end of a cementless hip prosthesis and the proximal end of a dynamic compression screw (DCS) is described. The method involves bridging the two implants using a bipolar shortened femoral nail. The proximal connection is secured by telescoping the stem of the hip prosthesis into the shortened femoral nail, which is further improved by filling the gap between the stem and the femoral nail with an Enders nail. The distal connection is secured by placing the distal locking screw of the femoral nail through the distal femoral plate of the dynamic compression plate first before locking the nail to the distal femur. Further stabilisation and promotion of healing at the distal femur were achieved using cement and bone graft.     

Stress analysis of the distal locking screws for femoral interlocking nailing.

In femoral locked nailing, the distal locking screws are vulnerable to mechanical failure. Biomechanical studies have shown that the stress on these screws is substantially affected by the fit of the nail in the medullary canal. In this study, a "closed form" mathematical model based on elastic beam-column theory was developed to investigate how the nail-cortical contact, which was simulated by a linear elastic foundation, affected the stress on the distal locking screws. Providing data for the model was a construct of a fractured femur with an intramedullary locked nail loaded by an eccentric vertical load. The stress on the locking screw was analyzed as a function of the distance from the fracture to the locking screw in the distal fragment under two situations: with and without nail-cortical contact in the distal fragment. With nail-cortical contact, the screw stress decreased as the length of nail-cortical contact and the distance between the distal locking screw and the fracture site increased, but this stress contrarily increased when the nail reached the femoral region at which the screw length increased. The screw stress was much higher without nail-cortical contact than with contact and continued to increase as the nail was inserted further. The mathematical model developed here can be a convenient means of rapid stress evaluation and parametric analysis for locked femoral nailing. It may be used to improve the design of interlocking nails and surgical technique.     

The trochanteric nail versus the sliding hip screw for intertrochanteric hip fractures: a review of 93 cases

BACKGROUND: The trochanteric nail, a redesigned short gamma nail, (Howmedica, Rutherford, NJ) was introduced in the United States during 1998 for the treatment of intertrochanteric fractures. METHODS: We retrospectively reviewed 93 patients who were treated for an intertrochanteric fracture with either a sliding hip screw (SHS) or the short trochanteric nail (TN). RESULTS: In all, 94% of the patients in the sliding hip screw group healed without complication. There was one case of femoral head necrosis, one lag screw cutout, and one hardware removal for pain. Eighty-nine percent of the patients in the trochanteric nail group healed without complication. There was one late fracture at the tip of the nail, three cases of lag screw cutout, and one nonunion. CONCLUSIONS: This study suggests that the trochanteric nail is a reasonable alternative to the sliding hip screw when used for intertrochanteric fractures, although it may be associated with higher complication rates.     

Proximal femoral nail for treatment of trochanteric femoral fractures

PURPOSE: To report outcomes of 87 consecutive patients treated with a proximal femoral nail (PFN) for trochanteric femoral fractures. METHODS: 17 men and 70 women aged 58 to 95 (mean, 85) years with trochanteric femoral fractures underwent PFN fixation using an intramedullary nail, a lag screw, and a hip pin. Fractures were classified according to the AO system; the most common fracture type was A2 (n=45), followed by A1 (n=36) and A3 (n=6). The position of the lag screw within the femoral head was measured. The lateral slide of the lag screw after fracture consolidation was measured by comparing the immediate postoperative and final anteroposterior radiographs. RESULTS: 90% of lag screws were placed in an optimal position. The length of lateral slide of the lag screw in stable A1 fractures was significantly less than that in unstable A2 fractures; it was over 10 mm in 7 of 45 patients with A2 fractures. Cut-out of lag screw did not occur, suggesting that free sliding of the lag screw facilitates direct impaction between fragments. CONCLUSION: A PFN is useful for the treatment of trochanteric femoral fractures.     

Submuscular plating of pediatric femur fracture

Currently, surgical management of pediatric femur fracture consists of intramedullary nailing with flexible nails or rigid trochanteric entry nails. Rigid trochanteric entry nails are the implant of choice for femoral fractures in adolescents, whereas titanium elastic nails are popular for the management of length-stable diaphyseal femoral fractures in school-age children. However, higher complication rates have been reported in children with length-unstable diaphyseal femoral fractures treated with titanium elastic nails. These complications may require unplanned surgery. Fracture shortening or angulation can lead to nail prominence or exposure that may require nail shortening or removal. Recently, submuscular plating has been found to be a successful alternative option for management of length-unstable femoral fractures in school-age children. Submuscular plating can also be used in older and/or heavier children who have a femoral canal that is too small to accommodate a rigid intramedullary nail.     

Early experience with the gamma interlocking nail for peritrochanteric fractures of the proximal femur.

Surgical fixation, early weight-bearing, and bony union remain a challenge in the treatment of peritrochanteric femur fractures, especially if the fractures are comminuted or unstable. Preliminary experience with the Gamma locking nail, a short intramedullary nail connected to a sliding compression screw augmented with distal locking screws, is presented. In a consecutive series of 29 patients, all fractures were adequately reduced and immediate weight-bearing was begun regardless of fracture configuration (13/27 fractures classified as unstable). Twenty-seven patients were reviewed at 6 months. At follow-up, all patients continued to be ambulatory and all fractures healed. Major complications included screw migration in the femoral head (two patients), difficulty in securely placing the distal screws (eight patients), and a femoral shaft fracture through the distal locking screws following a fall. The technical problems inherent in the device and its instrumentation are discussed. In this early experience, the Gamma nail appears to allow for early patient ambulation regardless of the fracture configuration with excellent clinical results.     

A randomized study of the compression hip screw and Gamma nail in 426 fractures

A prospective, randomized study comparing the compression hip screw with the Gamma nail in the treatment of 426 intertrochanteric fractures is reported. The median patient age was 80 years, and 71% were women The compression hip screw operation took less time except in Evans Type 5 fractures. Blood loss generally was less in the compression hip screw group except in patients with Type 5 fractures. The most frequent surgical problem for patients in the Gamma group was problems with distal locking. Cephalic position of the femoral head screw and cut-out were seen more often in the Gamma nail group. The Gamma nail more frequently preserved the fracture position obtained perioperatively. Whether there was distal locking of the Gamma nail in unstable fractures did not seem to affect the healing rate. Additional fissures or fractures in the proximal femur occurred during five Gamma nail operations and two compression hip screw operations. Postoperative walking ability did not differ between the groups. At 6 months 88% of the fractures were healed. In less comminuted fractures, the compression hip screw method is the preferred method of treatment whereas the Gamma nail is an alternative treatment for more comminuted Evans Type 5 fractures.     

Use of Huckstep nail in the periimplant femoral shaft fracture

87-year-old female underwent open reduction of distal femoral fracture and internal fixation with locking compression plate and bone graft. She was operated for ipsilateral proximal femoral fractures and stabilized by intramedullary interlocked nail 5 years ago. She developed stress fracture proximal to locked plate. We inserted Huckstep nail after removal of the previous operated proximal femoral nail without removing the remaining plate and screws. At 15 month followup the fractures have united. The Huckstep nail has multiple holes available for screw fixation at any level in such difficult situations.     

Infra-isthmal fracture is a risk factor for nonunion after femoral nailing: a case–control study

Background

The rates of nonunion after femoral nailing are currently reported to be 4.1–12.5 %. The purpose of this study was to identify the risk factors of noninfected nonunion after femoral nailing, focusing in particular on the effects of the length of the distal main fragment.

Methods

A case–control study was conducted with 105 patients, with a case (nonunion group)–control (control group) ratio of 1:2. The nonunion group (n = 35) comprised patients with consecutive symptomatic nonunions after femoral nailing who were treated in our institute; the control group (n = 70) were matched by age to the nonunion group. Type of fracture, soft tissue injury, length of femur and nail length, incidence of screw breakage, nail diameter, mean length of distal main fragment, and any episode of dynamization were retrospectively examined. Univariate and multivariate analyses were performed to elucidate the risk factors of nonunion after femoral nailing.

Results

Increased risk of nonunion after femoral nailing was associated with (1) open fracture, (2) screw breakage, (3) shorter length of a distal fragment, and (4) any episodes of dynamization. Receiver operating characteristic analysis showed that a distal fragment length of <43 % of the total femur length was the cutoff level for nonunion after nailing. The odds ratio for nonunion was 6.40 (95 % CI 2.70–15.2) when the length of the distal main fragment was <43 % of the femur length. Multivariate logistic analysis revealed that the risk of nonunion after femoral nailing increased (1) with breakage of locking screws (p = 0.0021), (2) with dynamization (p = 0.0029), (3) with a shorter distal fragment length (p = 0.0379), and (4) with an open fracture (p = 0.0397).

Conclusion

The elucidated risk factors of nonunion after femoral nailing were identified as open fracture, infra-isthmal femoral fracture, breakage of locking screw, and inappropriate dynamization. We believe that the surgeon should be consciously aware of the need for additional surgical fixation for the distal fragment when performing femoral nailing of infra-isthmal femoral fractures.     

Intrapelvic migration of hip lag screw of proximal femoral nail-sequele to a paradoxical reverse Z effect and their critical analysis

A 40-year-male treated with hip screw for unstable inter trochanteric fracture femur, had an implant failure after an aggressive therapy session .The Dynamic Condylar Screw was removed and fracture was fixed with Proximal Femoral Nail. The nail also failed to achieve its goal of fracture union, as a result of a unique type of reverse Z effect, in contradiction to expected Z effect resulting in intrapelvic migration of proximal hip lag screw of the proximal femoral nail.     

股骨干骨折合并同侧股骨颈骨折治疗的临床观察

目的：探讨股骨干合并同侧股骨颈骨折的治疗特点和不同固定方法的疗效。方法：股骨干骨折合并同侧股骨颈骨折27例,男22例,女5例;年龄14～65岁,平均35岁。动力髋螺钉（DHS）固定3例,加压钢板加空心加压螺钉固定12例,重建钉固定8例,顺行髓内钉加空心加压螺钉固定4例。13例固定术前用克氏针临时固定股骨颈骨折。结果：术后随访36～75个月,平均44个月。25例股骨颈骨折平均愈合时间4.5个月,2例股骨颈骨折不愈合。27例股骨干均愈合,平均愈合时间6个月。未用克氏针临时固定股骨颈骨折14例中,2例出现股骨颈不愈合,3例轻度髋内翻畸形。结论：股骨干合并同侧股骨颈骨折有许多固定方法可供选择,加压钢板加空心加压螺钉固定简便易用,在实施固定术前用克氏针临时固定股骨颈骨折可避免股骨颈骨折再移位和损伤。     

Finite element study of the proximal femur with retained trochanteric gamma nail and after removal of nail

This study aims to evaluate the stress and strain distributions in the healed proximal femur after fixation with a trochanteric gamma nail (TGN) and after TGN removal, using the finite element method. The stress distributions in the proximal femur with retained TGN and after TGN removal were very similar. The strain and the strain energy density in the femoral neck region with retained TGN were much higher than in the lag screw hole at the subtrochanter and the distal locking screw hole at the proximal femur, and even higher after TGN removal. Stair climbing resulted in higher strain and higher strain energy density at the femoral neck than normal walking. The conclusion can be drawn that removal of the TGN may result in high risk of femoral neck fracture.     

Breakage of sliding hip screw after fixation of pertrochanteric hip fracture: A rare complication

IntroductionThe authors report a rare case of lag screw breakage in a patient treated using locking DHS with home-made trochanteric stabilizing plate (TSP) for pertrochanteric hip fracture.Case presentationA 67 year-old female was operated for pertrochanteric hip fracture with incompetent lateral wall using locking DHS with home-made TSP. At seven months postoperative, there was radiographic nonunion with breakage of the sliding lag screw. Patient was consequently scheduled for total hip replacement.DiscussionBreakage of DHS lag screw has been attributed to multiple-cycle, low-stress fatigue failure associated with nonunion. Predisposing factors are: situation of the medial edge of the barrel at the level of the fracture site prohibiting fracture compression, and mechanical obstacle to the lag screw back sliding into the barrel. In our case, the use of handmade TSP interdicted lag screw back sliding and prevented fracture impaction which was already impaired by the location of the medial edge of the barrel at the fracture level. Additionally our fixation construct was very rigid because of the use of locking screws in the DHS side plate.ConclusionWhen DHS fixation is planned for unstable or potentially unstable trochanteric hip fracture the surgeon should be prepared by making available a TSP from the manufacturer in the operative room rather than improvising intra-operatively with handmade TSP; this augmentation device shouldn't interfere with lag screw back sliding. Furthermore the DHS barrel should ideally not impinge with the fracture site, and the use of locking screws in the DHS plate should be cautious.     

Reverse distal femoral locking compression plate a salvage option in nonunion of proximal femoral fractures

Background:When primary fixation of proximal femoral fractures with implants fails, revision osteosynthesis may be challenging. Tracts of previous implants and remaining insufficient bone stock in the proximal femur pose unique problems for the treatment. Intramedullary implants like proximal femoral nail (PFN) or surface implants like Dynamic Condylar Screw (DCS) are few of the described implants for revision surgery. There is no evidence in the literature to choose one implant over the other. We used the reverse distal femur locking compression plate (LCP) of the contralateral side in such cases undergoing revision surgery. This implant has multiple options of fixation in proximal femur and its curvature along the length matches the anterior bow of the femur. We aimed to evaluate the efficacy of this implant in salvage situations.Results:All fractures exhibited union without any complications. Union was assessed clinically and radiologically. One case of ipsilateral femoral neck and shaft fracture required bone grafting at the second stage for delayed union of the femoral shaft fracture.Conclusions:Reverse distal femoral LCP of the contralateral side can be used as a salvage option for failed fixation of proximal femoral fractures exhibiting nonunion.     

Biomechanical comparison of a 2 and 3 proximal screw-configured antegrade piriformis intramedullary nail with a trochanteric reconstruction nail in an unstable subtrochanteric fracture model

OBJECTIVE: The objective of this study was to test the stiffness and ultimate load to failure of new intramedullary (IM) nail proximal screw configurations as compared to a trochanteric reconstruction nail. METHODS: Twenty-one synthetic composite femurs were mounted on a Material Testing System and tested in axial compression 5 times. The femurs had an 1 of 2 IM nail types inserted with 1 of 3 proximal screw configurations: a 3-screw configuration with 2 transverse screws and a screw angled into the femoral neck; a 2-screw design with a single transverse screw and a single screw angled into the femoral neck; 2 parallel screws angled into the femoral neck. There were 7 specimens in each group. An unstable fracture (OTA/AO 32-C3.2) was created. and the stiffness of these constructs was tested in compression 5 times. Each construct was then loaded to failure in compression. RESULTS: The 3-screw construct provided more axial stiffness (214 N/mm +/- 75) than either the 2-screw construct (123 N/mm +/- 32) or the trochanteric reconstruction nail (127 N/mm +/- 21) (P = 0.017 and 0.035 for 3-screw vs. 2-screw and recon respectively, P = 0.45 for 2-screw vs. recon). Load-to-failure testing demonstrated similarity among the different screw configurations (3-screw = 2230 N +/- 265, 2-screw = 2283 N +/- 260, Reconstruction nail = 2121 N +/- 156) (P = 1.0 all groups). CONCLUSIONS: The proximal 3-screw configuration provided more stiffness than either the 2-screw configuration or trochanteric reconstruction nail. The 2-screw configuration performed equally to a standard trochanteric reconstruction nail in stiffness testing. The ultimate loads to failure for the 3 tested constructs were not significantly different.     

股骨转子间骨折初次手术失败的翻修策略和研究进展

股骨转子间骨折是最常见的髋部骨折。由于严重骨质疏松及骨折断端粉碎程度高,初始内固定失效或骨折不愈合时有发生。对于功能需求高和（或）预期寿命长的手术失败患者,如何制定更为有效的翻修固定策略尚存在争议。常用的手术方式包括角度稳定钢板髓外系统（动力髁螺钉或动力髋螺钉）固定、股骨近端头颈髓内钉系统（股骨近端防旋髓内钉、Inte...     

Distal locking in short hip nails: Cause or prevention of peri-implant fractures?

ObjectivesThe most common cause of femoral fractures after osteosynthesis of trochanteric fractures with short nails is weakening of the femoral cortex via distal locking and stress concentrations at the tip of the nail. The aim of the study was to verify whether the incidence of peri-implant fractures is dependent upon the distal locking technique.MethodsWe prospectively analysed a group of 849 pertrochanteric fractures (AO/ASIF 31-A1 + 2) managed with short nails from 2009 to 2013. Unlocked nailing was performed in 70.1% and distal dynamic locking was performed in 29.9%. The mean age was 82.0 years. Peri-implant fractures were divided into 3 groups according to the height of the fracture in relation to the tip of the nail.ResultsIn total 17 fractures (2.0%) were detected. One peri-implant fracture occurred after locked nailing, whereas 16 cases occurred after unlocked nailing (p = 0.037). Patients without distal locking had an 85.7% greater risk of peri-implant fracture. Fractures of the proximal femur (Type I) occurred significantly earlier than fractures at the tip of the nail (Type II) (p = 0.028).ConclusionUnlocked nails do not guarantee sufficient stability. Distal locking serves to prevent postoperative femoral fractures. We recommend the routine use of distal locking when utilizing short nails.