Femoral shaft fracture below a pre-existing implant: a novel method of fixation: a case report

Femoral shaft fractures below or above a pre-existing implant in the elderly are not uncommon, and the ideal management of these fractures is not well defined. We report the use of a retrograde femoral nail for a femoral shaft fracture, linked to a pre-existing hip plate screw construct by locking the nail through the distal two holes of the plate. We were able to achieve a biomechanically stable construct with no gapped areas and no stress risers in osteopenic bone. This technique is one of the various methods that can be chosen to fix a fracture with a pre-existing implant proximally.     

The effect of implant overlap on the mechanical properties of the femur

BACKGROUND: The most biomechanically stable relationship between the side plate of a compression hip screw (CHS) and retrograde intramedullary (IM) femoral nail has not been described in the literature. This becomes a clinical issue when treating supracondylar femur fractures with a retrograde nail in patients with a history of compression hip screw fixation of intertrochanteric fractures. The proximal end of the nail and the interlocking screws may act as a stress riser in the femoral diaphysis. The purpose of this study is to determine the biomechanical consequences of the amount of implant overlap between a CHS plate and retrograde IM femoral nail. METHODS: Nine paired fresh-frozen cadaver femora from elderly donors were cleaned of soft tissue and fixed with uniaxial strain gauges. Each femur was loaded three times in a fall-loading configuration to 50 kg at a rate of 1 Hz. The study consisted of two phases. In phase 1, six pair were randomly divided into a control and test femur from each pair. Three states were compared on each test femur: uninstrumented, instrumented with CHS, and instrumented with CHS and retrograde nail. The control femur consisted of the matched femur tested in two states: uninstrumented and instrumented with a CHS. The femora were then loaded to failure. The tests were performed with the retrograde nail and CHS gapped 3 cm, kissing, and overlapping by two screw holes (two pair for each state). In phase 2, each of the remaining three pair were instrumented with a CHS and retrograde nail overlapping in one femur and gapped in the matched femur and tested in the same manner. Data analysis was performed using Pearson's correlation coefficients between groups. Paired samples t tests were used to compare differences within test states and independent samples t tests were used to compare differences between femora. Mean strain at 50-kg load, load-versus-strain patterns, failure patterns, and load and strain at failure were recorded. RESULTS; Correlation coefficients were greater than 0.98 within and between pairs (p < 0.001). There were statistically significant differences (p < 0.05) in strain patterns between the uninstrumented, CHS, and CHS/IM test states. The addition of a side plate significantly (p < 0.05) increased lateral compressive strains in the femoral diaphysis. Mean strain at 50-kg load was significantly (p < 0.05) altered by the addition of the retrograde nail in all three implant orientations. Gapped implants failed at lower loads and strains than femurs with kissing and overlapping implants. Gapped constructs failed at lower loads than control states. Overlapped constructs tolerated the highest loads and strains before failure. CONCLUSION: Strain patterns are altered by the degree of implant overlap in the proximal femoral diaphysis. Femora with uninstrumented intervals between retrograde nails and side plates fail at lower loads than femora without retrograde nails and those with kissing or overlapping implants. Kissing or overlapping instrumentation increases load to failure and creates a more biomechanically stable construct than gapped implants. The findings of this study suggest an overlapping implant orientation in the femur increases failure load at the implant interface.     

Retrograde femoral interlocking nail in complex fractures

Retrograde interlocking nail was used as the method of fixation in 35 different cases of combination of complex femoral fractures. We performed this procedure in fractures of femoral shaft associated with fracture neck femur, pathological fractures of proximal third of femur with trochanteric pathology, ipsilateral fracture of femur and tibia in polytrauma cases with multiple other injuries, in highly obese patients with fracture shaft femur. This technique was also used in cases of pregnancy with fracture shaft femur and in unstable pelvic fracture or dislocation hip associated with fracture shaft femur. Operative technique involved with retrograde insertion of un-reamed, non-cannulated custom made nail through entrance portal in intercondylar notch was applied for fixation of the shaft femur fracture. The other associated fracture around hip was stabilized separately using suitable implant according to type of fracture. In cases of ipsilateral fracture of femur and tibia, femur was stabilized by retrograde interlocking nail and tibia was stabilized by antigrade interlocking nail through same incision at the same sitting. The case was followed up for three years; the average union time was 12 to 18 weeks. Out of 35 cases, 31 cases regained full knee movement. Out of the remaining 4 cases, 2 cases could regain up to 90 degrees of movement, these were old fractures and non-cooperative patients. In one case, patellofemoral arthritis was developed because of an operative error where a nail was not put inside the articular surface. Mal-union was observed in an early case of the series and implant failure was nil. Retrograde interlocking nail was used as the method of fixation in complex fracture problems. Multiple fractures of long bones can be stabilized in one stage, preventing multiple operations at different stages in polytraumatized patients. This resulted in early recovery, lesser hospital stay, and early rehabilitation of patient with good results and is economical also.     

Subtrochanteric fractures after retrograde femoral nailing

Secondary fractures around femoral nails placed for the management of hip fractures are well known. We report, two cases of a fracture of the femur at the interlocking screw site in the subtrochanteric area after retrograde femoral nailing of a femoral shaft fracture. Only a few reports in the existing literature have described these fractures. Two young men after sustaining a fall presented to us with pain, swelling and deformity in the upper thigh region. On enquiring, examining and radiographing them, peri-implant fractures of subtrochanteric nature through the distal interlocking screws were revealed in both patients who also had histories of previous falls for which retrograde intramedullary nailing was performed for their respective femora. Both patients were managed with similar surgical routines including removal of the existing hardware, open reduction and ace cephallomedullary antegrade nailing. The second case did show evidence of delayed healing and was additionally stabilized with cerclage wires. Both patients had uneventful postoperative outcomes and union was evident at the end of 6 mo postoperatively with a good range of motion at the hip and knee. Our report suggests that though seldom reported, peri-implant fractures around the subtrochanteric region can occur and pose a challenge to the treating orthopaedic surgeon. We suggest these be managed, after initial stabilization and resuscitation, by implant removal, open reduction and interlocking intramedullary antegrade nailing. Good results and progression to union can be expected in these patients by adhering to basic principles of osteosynthesis.     

What is the risk of stress risers for interprosthetic fractures of the femur? A biomechanical analysis

Purpose

Due to increasing life expectancy we see a rising number of joint replacements. Along with the proximal prosthesis in the femur, more and more people have a second implant on the distal ipsilateral side. This might be a retrograde nail or a locking plate to treat distal femur fractures or a constrained knee prosthesis in the case of severe arthrosis. All these constructs can lead to fractures between the implants. The goal of this study was to evaluate the risk of stress risers for interprosthetic fractures of the femur.

Methods

Thirty human cadaveric femurs were divided into five groups: (1) femurs with a prosthesis on the proximal side only, (2) hip prosthesis on the proximal end and a distal femur nail, (3) femurs with both a hip prosthesis and a constrained knee prosthesis, (4) femurs with a hip prosthesis on the proximal side and a 4.5-mm distal femur locking plate; the locking plate was 230 mm in length, with ten holes in the shaft, and (5) femurs with a proximal hip prosthesis and a 4.5-mm distal femur locking plate; the locking plate was 342 mm in length, with 16 holes in the shaft.

Results

Femurs with a hip prosthesis and knee prosthesis showed significantly higher required fracture force compared to femurs with a hip prosthesis and a distal retrograde nail. Femurs with a distal locking plate of either length showed a higher required fracture force than those with the retrograde nail.

Conclusions

The highest risk for a fracture in the femur with an existing hip prosthesis comes with a retrograde nail. A distal locking plate for the treatment of supracondylar fractures leads to a higher required fracture force. The implantation of a constrained knee prosthesis that is not loosened on the ipsilateral side does not increase the risk for a fracture.     

A biomechanical evaluation of the Gamma nail.

We examined the effect of the Gamma nail on strain distribution in the proximal femur, using ten cadaver femora instrumented with six unidirectional strain gauges along the medial and lateral cortices. The femora were loaded to 1800 N and strains were determined with or without distal interlocking screws before and after experimentally created two-part and four-part fractures. Motion of the sliding screw and the nail was also determined. Strain patterns and screw motion were compared with previously obtained values for a sliding hip screw device (SHS). The Gamma nail was shown to transmit decreasing load to the calcar with decreasing fracture stability, such that virtually no strain on the bone was seen in four-part fractures with the posteromedial fragment removed; increasing compression was noted, however, at the proximal lateral cortex. Conversely, the SHS showed increased calcar compression with decreasing fracture stability. The insertion of distal interlocking screws did not change the pattern of proximal femoral strain. The Gamma nail imparts non-physiological strains to the proximal femur, probably because of its inherent stiffness. These strains may alter bone remodelling and interfere with healing. Distal interlocking screws may not be necessary for stable intertrochanteric fractures.     

Peri-implant atypical femoral fracture after nail or plate osteosynthesis

BackgroundA lack of scientific information regarding the risk factors and diagnosis of peri-implant atypical femoral fracture (PI-AFF) exists. We report a case series of developed PI-AFF with a nail or plate construct wherein prior femoral fractures were already healed after osteosynthesis. This study aimed to identify the cause and risk factors of PI-AFF and to devise a preventive method based on this.MethodsWe identified 11 PI-AFFs displaying features of AFFs. All patients were ambulant females (mean age, 74.9 years). The mean T-score of the femur measured by DEXA (Dual Energy X-ray Absorptiometry) scan was 3.5. Osteosynthesis was performed with a plate and an intramedullary nail in six and five patients, respectively. Possible risk factors were investigated, including the used implant, the medication of bisphosphonate, the characteristics of previous fracture (AFF or non-AFF), and the co-existence of AFF on the contralateral side.ResultsThe PI-AFFs developed at an average of 6.6 years from the time of prior fracture. All fractures were located at the screw through the plate or nail. Regarding anatomic locations, seven and four fractures were at the subtrochanteric area and diaphysis, respectively. Diaphyseal PI-AFFs occurred in plating cases, all of which were associated with excessive femoral bowing. Subtrochanteric PI-AFFs included all five patients with nail fixation, which occurred near a proximal interlocking screw. Six of the 11 patients were on bisphosphonate treatment before or at the time of fracture. The duration of bisphosphonate treatment was 6 years on average. Concerning the previous femoral fractures, seven and four patients were AFF and non-AFF, respectively. Considering the pathology on the contralateral leg, eight had suffered diaphyseal AFF. Four patients were treated nonoperatively. Seven patients needed an operation; 6 of them healed after reconstruction nailing, and one needed hip arthroplasty because of the associated displaced femoral neck fracture.ConclusionsPI-AFFs may develop through the screw hole at the subtrochanteric or diaphyseal area due to femoral fragility and stress riser effect of the implant. An improved osteosynthesis strategy may be necessary to avoid PI-AFFs when fixing osteoporotic femoral fractures.     

Intramedullary nailing of femoral shaft fractures. Part III: Long-term effects of static interlocking fixation.

The results of treatment of fractures of the femoral shaft with static interlocking nailing were reviewed retrospectively to determine the clinical importance of any stress-riser or stress-shielding properties of the nail. These properties, if relevant, would have been manifested by refracture of the femur, either through a hole used for a locking screw or through the original site of fracture after extraction of the device. Two hundred and fourteen fractures that had been treated with static interlocking nailing and that had healed without conversion to dynamic intramedullary fixation were divided into two groups. In Group I, which comprised 111 fractures, the static interlocking-fixation device was retained and in Group II, which comprised 103 fractures, the static interlocking-fixation device was removed during one operative procedure at an average of fourteen months after the injury. The average duration of follow-up was thirty months from the time of the original fixation in both groups. All patients in Group II were followed for a minimum of six months after removal of the nail. No femur in Group I, in which the static interlocked nail remained in situ, refractured. No femur in either group fractured through the proximal or the distal holes used for the locking screws. No locking screws or nails broke. One patient (1 per cent) in Group II had a refracture of the femoral shaft through the site of the original fracture six weeks after removal of the nail.(ABSTRACT TRUNCATED AT 250 WORDS)     

Gamma钉和DHS/Richard钉治疗股骨近端骨折相比较的Meta分析

目的评价Garoma钉和DyiS (Dynanlic Hip screw)／Rirhard钉治疗股骨近端骨折的疗效和安全性。方法 应用(Cochrance协作网Meta分析方法对关于Garoma钉和DHs／Richard钉治疗股骨近端骨折的随机或半随机对照试验进行Meta分析。结果 我们检索出1969～2003年间发表的88篇关于Ganmla钉和DHs／Richard钉治疗股骨近端骨折相比较的文献，经过筛选和评价，最后收集到已发表的7篇(共1256例患者)随机或半随机对照试验，符合本次Meta分析所纳入的试验标准。4个临床试验共包括62l例患者，提供了关于术后前6个月的死亡率的详细信息。我们发现Gamma钉术后头6个月与DHs／Richard钉相比较的死亡的相对危险度无明显统计学差异(相对危险度1．17，p=0．51)。6个试验包括1083例患者提供了并发症的资料。Garoma钉和DHS／Rithard钉内固定的相对危险度是1．4l(p：0．02)。Gamma钉明显的增加了股骨干骨折的危险(相对危险度6．99：p=0．00)，二次手术率增加(相对危险度1．85；p=0．20)。此外，Gamma钉与DHS／Richard钉相比较，患者的手术时间缩短，手术失血量及术后功能恢复相同。结论 通过此次Meta分析发现，对于治疗股骨近端骨折，Gamma钉与DHS／Richard钉相比较，在死亡率、伤口感染率、手术失血量、术后功能的相对危险度无明显统计学差异，但增加并发症，尤其明显的增加了股骨干骨折的危险，二次手术率有增加趋势。     

Implant Breakage of the Proximal Femoral Nail (PFN) Reasons and Case Reports

Case Reports: In three subtrochanteric femoral fractures (AO classification 31 A.3) treated with a proximal femoral nail (PFN), the implant broke at the level of the hole for the femoral neck screw. All three PFN had been statically interlocked. Treatment: The broken intramedullary part of the system could be removed in all cases. In two cases refixation was achieved with a dynamic hip screw (DHS) and a long plate, in one case with a 95° AO blade plate. Reasons for Implant Breakage: Implant failure was caused by delayed fracture healing due to statistic interlocking. This could have been prevented by early dynamization. On the other hand, the implant may have failed due to excessive strain on the load-bearing element, whose load bearing limit probably had been exceeded by the fact of load transmission over a long period of time.     

Femoral fracture at the proximal end of an intramedullary supracondylar nail: a case report

Retrograde intramedullary supracondylar nails have been added to the orthopedic armamentarium for treatment of distal femoral fractures. Major complications of this new technique have not been noted. We report a case of a femoral fracture at the proximal end of a retrograde intramedullary supracondylar nail. We hypothesize that this complication may be due to the proximal end of the nail acting as a stress riser, with the cortical holes drilled for the interlocking screws compounding this effect.     

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.     

股骨复合型带锁髓内钉的设计及临床应用

目的 阐述股骨复合型带锁髓内钉(femoral compound interloeking intramedullary nail,FCIIN)的设计原理,探讨其临床疗效.方法 根据股骨髓腔形态学特点,没计FCIIN的主钉弧度半径为1250 mm,近端斜形交锁角度(钉的颈干角)为135°.主钉近端有三个直径6.5 mm的锁钉孔,使锁钉可以横穿,也可以向左上或下、右上或下45°斜穿.主钉远端有两个直径4.5 mm的锁钉孔和一个相同直径的凹槽.近端锁钉尖部有长30～40 mm自攻松质骨螺纹,螺纹直径由3.5 mm逐渐增大至6.5 mm.远端锁钉有两种:一种是螺纹锁钉,另一种是螺栓锁钉.2000年1月至2004年12月,用FCIIN治疗股骨骨折患者47例,男31例,女16例;年龄18～74岁,平均39.83岁;转子间骨折14例,转子下骨折7例,股骨干骨折18例,髁上骨折8例.其中不扩髓顺行打钉30例.结果 所有患者均获得随访,随访时问21～36个月,平均25.9个月.骨愈合时间6～18个月,平均8.4个月.解剖复位34例,良好复位11例,力线复位2例,复位优良率95.74%.取钉时问12～21个月,平均16.9个月.1例转子间骨折固定失败并骨不愈合患者,采用辅助外固定支架治疗,18个月后骨折愈合.远端锁钉安装失败5例,未做任何处理骨折均愈合.结论 FCIIN 临床应用效果理想,可用于治疗各类股骨骨折.     

A biomechanical comparison of proximal femoral nails and locking proximal anatomic femoral plates in femoral fracture fixation: A study on synthetic bones

Background:The incidence of fractures in the trochanteric area has risen with the increasing numbers of elderly people with osteoporosis. Although dynamic hip screw fixation is the gold standard for the treatment of stable intertrochanteric femur fractures, treatment of unstable intertrochanteric femur fractures still remains controversial. Intramedullary devices such as Gamma nail or proximal femoral nail and proximal anatomic femur plates are in use for the treatment of intertrochanteric femur fractures. There are still many investigations to find the optimal implant to treat these fractures with minimum complications. For this reason, we aimed to perform a biomechanical comparison of the proximal femoral nail and the locking proximal anatomic femoral plate in the treatment of unstable intertrochanteric fractures.Result:Nail and plate models were locked distally at the same level. Axial steady load with a 5 mm/m velocity was applied through the mechanical axis of femur bone models. Axial loading in the proximal femoral intramedullary nail group was 1.78-fold greater compared to the plate group. All bones that had the plate applied were fractured in the portion containing the distal locking screw.Conclusion:The proximal femoral intramedullary nail provides more stability and allows for earlier weight bearing than the locking plate when used for the treatment of unstable intertrochanteric fractures of the femur. Clinicians should be cautious for early weight bearing with locking plate for unstable intertrochanteric femur fractures.     

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.     

Treatment of ipsilateral hip and femoral shaft fractures with reconstructive intramedullary interlocking nail

Objective: To evaluate the results of reconstructive intramedullary interlocking nail in the treatment of ipsllateral hip and femoral shaft fractures. Methods: From August 1997 to November 2001, 13 patients were treated with the reconstructive intramedullary interlocking nail. Nine patients were associated with ipsllateral femoral neck fractures, three with ipsilateral intertrochanteric fractures, and one with subtrochanteric fracture. Results: The follow-up time was from 6 to 38 months with an average of 14 months. All the femoral shaft and hip fractures healed up well. There was no nonunion of the femoral neck, and only one varns malunion. No patient had avascular necrosis of the femoral head. The average healing time for femoral neck fracture was 4.6 months and for shaft fracture 5.8 months. The joint movement and other functions were fairly resumed. Conclusions: The reconstructive intramedullary interlocking nail, with less trauma, refiable fixation, and high rate of fracture healing, is an ideal method of choice in the treatment of ipsilateral hip and femoral shaft fractures.     

Intramedullary fixation of subtrochanteric fractures with the Williams Y-nail: report of three cases

Küntscher Y-nailing is indicated for unstable proximal fractures of the femur in the elderly (5-7,10). The Williams modified Y-nail is an interlocking Y-nail that was designed to extend the indications beyond those of the Küntscher Y-nail. The Williams Y-nail was employed in three cases of subtrochanteric and subtrochanteric-intertrochanteric fractures, including one case in which there was an ipsilateral femoral shaft fracture. This procedure requires reaming and interlocking which are not performed in classic Küntscher Y-nailing. At follow-up (14-month minimum), each patient had a good clinical result and radiographic healing. Leg length shortening (maximum, 1.5 cm) occurred in two of three cases, primarily as a result of the failure to employ either a proximal or a distal interlocking screw. No other deformities have been observed. Williams Y-nailing can extend the indications of the Küntscher Y-nail to include rotationally unstable subtrochanteric fractures and associated ipsilateral femoral shaft fractures. The increased technical demands of the Williams modified Y-nail warrant cautious use depending upon the complexity of the fracture. Used properly, the Williams Y-nail may reduce the incidence of rotational and leg length deformities often experienced with other commonly used devices for unstable subtrochanteric and ipsilateral trochanteric-diaphyseal fractures of the femur.     

Biomechanical evaluation of the proximal femoral nail

In 1997, the proximal femoral nail was introduced for treatment of peritrochanteric femoral fractures. Treatment results show a low complication rate. The most serious complication is cutout of the hip pin and femoral neck screw. Considerable load on the hip pin is thought to facilitate cutout. The biomechanical behavior of the hip pin and the femoral neck screw as part of the standard proximal femoral nail, and of an experimentally modified proximal femoral nail (in which the hole through the nail for the hip pin is modified to a slot) was studied. In the standard proximal femoral nail, the amount of the total load carried by the hip pin varies between 8% and 39% (mean, 21%). If the hip pin passes through a slot in the nail, it carries 2% to 8% (mean, 5%) of the load. The nonconstrained lateral end of the hip pin reduces the bending load applied to the implant. The slotted hole for the hip pin also allows the femur and the nail to medialize, even if the hip pin and femoral neck screw lose parallelism. The prevalence of cutout of the proximal femoral nail may be reduced by introduction of this mechanism.     

Retrograde intramedullary nailing of supracondylar femur fractures above total knee arthroplasty: A preliminary report of four cases

Four supracondylar fractures of the femur in three patients with total knee arthroplasties were treated by retrograde intramedullary nailing using an interlocking reamed nail (GSH Nail, Smith and Nephew Richards, Memphis, TN) specifically designed for fractures of the distal femur. Three cases were acute fractures and one was a refracture through a screw hole of a previously plated supracondylar fracture. All fractures healed and there were no complications. The procedure is performed by closed nailing using fluoroscopic guidance with the nail placed through the intercondylar notch of the femoral prosthesis and interlocking to the fracture fragments with a percutaneous targeting device. The advantages are that the procedure is performed by closed techniques that preserve the fracture hematoma and reduce operative blood loss, the fracture is stabilized by a load-sharing nail, and immediate motion with limited weight bearing is possible.