Trochanteric nail insertion for the treatment of femoral shaft fractures

OBJECTIVES: This study was designed to evaluate whether the use of a new femoral nail, specifically designed to be inserted through the greater trochanter, could eliminate the complications previously seen with insertion of straight nails through this entry portal for the treatment of femoral shaft fractures. DESIGN: Prospective, clinical trial. SETTING: Three level I trauma centers. PATIENTS: Sixty-one consecutive patients with femoral shaft fractures (50 closed and 11 open fractures) treated with antegrade nailing with insertion through the greater trochanter. INTERVENTION: All patients were treated in the supine position with a TAN nail (Trigen System, Smith & Nephew, Memphis, TN) inserted through the greater trochanter. MAIN OUTCOME MEASURE: Union, alignment, complications, and hip function. RESULTS: Forty-six of 57 (81%) surviving patients were available for follow-up at a minimum of 12 (range, 12-25) months. Union occurred in all but 1 fracture after the index procedure. No patient sustained iatrogenic fracture comminution, and there were no angular malunions. Pain was reported as slight in 6 patients and moderate in 2. Visual and videotaped gate analysis, performed on 24 patients, revealed symmetrical walking in 21. CONCLUSIONS: This study demonstrates that antegrade nailing of femoral shaft fractures with a specially designed nail inserted through a trochanteric starting point provides predictably high union rates and low rates of complications. Ease of entry and utility in patients with a large body habitus are advantages over conventional piriformis fossa entry techniques. Nailing through the greater trochanter with the patient supine is presently our treatment of choice for patients with femoral shaft fractures.     

Effect of piriformis versus trochanteric starting point on fixation stability of short intramedullary reconstruction nails

Recently, a new, shorter IM nail using two 6 mm reconstruction screws for proximal fixation was introduced in two versions for femoral insertion: piriformis fossa (FAN) and greater trochanter (TAN). These nails were compared experimentally for their fixation stability, proximal load transmission, and failure strength in an unstable intertrochanteric fracture model in cadaveric femurs. Vertical and axial loads were first applied to the intact femurs. Fractures were created, subsequent fixation applied, and the femurs underwent a series of both vertical and axial loading tests. There was no significant difference in strain readings between the nails for either axial loading or cyclical loading. There was no statistically significant difference between the loads to failure for the trochanteric nails and the standard antegrade nails. The average ultimate loadfor the FAN and TAN nails were 3010 N and 2830 N respectively. These two nails performed very similarly throughout our testing.     

A critical analysis of the eccentric starting point for trochanteric intramedullary femoral nailing

OBJECTIVES: Antegrade femoral intramedullary nailing through a greater trochanteric insertion site has been proposed for the treatment of subtrochanteric fractures. The currently available trochanteric nails have dissimilar characteristics, and the most appropriate insertion site for satisfactory subtrochanteric fracture alignment has not been determined. This study is an analysis of 5 different trochanteric femoral nails and 3 different insertion sites using a cadaveric model of a reverse obliquity subtrochanteric femur fracture to determine the optimal trochanteric entry site. SETTING: OSHA-approved cadaveric laboratory with an OEC 9800 (General Electric Company, Fairfield, CT) fluoroscopic C-arm. METHODS: Twenty-one embalmed human cadaveric femurs were stripped of soft tissues. Three different starting points on the anteroposterior radiograph were used: at the tip of the greater trochanter, and 2 to 3 mm medial and lateral to the tip. A reverse obliquity subtrochanteric fracture was created. The Trochanteric Antegrade Nail (TAN), Gamma nail (2nd and 3rd generations), Trochanteric Fixation Nail (TFN), and the Holland Nail were then inserted. The proximal bend and radius of curvature were calculated for each nail. Varus and valgus angulation as well as lateral gapping were measured on radiographs; also calculated were the mean, range, and standard deviation. Statistical analysis was performed on angulation and gapping at the fracture site by using Fisher least significant differences analysis, based on a 2-way ANOVA test. RESULTS: The Holland nail had a proximal bend of 10 degrees and a radius of 300 cm. TAN was 5 degrees and 350 cm, TFN was 6 degrees and 150 cm, Gamma 2 was 4 degrees and 300 cm, and Gamma 3 was 4 degrees and 200 cm. The tip starting point led to the most neutral alignment regardless of nail. The lateral starting point led to varus with all nails. The medial starting point led to valgus of >6 degrees with the Holland and TFN; Gamma and TAN had better alignment with <4 degrees of valgus. Gapping of the lateral cortex was greatest with a lateral starting point. CONCLUSIONS: An analysis of 5 trochanteric intramedullary nails with different proximal bends and 3 different starting points in the greater trochanter showed that the tip of the trochanter is close to the "universal" starting point. In this cadaveric subtrochanteric fracture model, the tip starting point led to the most neutral alignment regardless of nail used. The lateral starting point led to varus and gapping of the lateral cortex with all nails. CLINICAL RELEVANCE: Subtrochanteric fractures treated with a trochanteric antegrade nail should have an acceptable reduction before nail insertion. The tip of the trochanter, or even slightly medial, on anteroposterior fluoroscopy is recommended as the universal starting point for these nails. However, slight deviations from this point and nail geometry can cause fracture site malalignment. A lateral starting point led to varus alignment and should be avoided.     

Entry point soft tissue damage in antegrade femoral nailing: a cadaver study

INTRODUCTION: Little attention is paid to insertion site morbidity associated with antegrade femoral nailing. However, residual peritrochanteric pain after nailing is not uncommon. Additionally, the end branches of the medial femoral circumflex artery (m.f.c.a.) supplying the femoral head are in close proximity to the insertion site of the nail, and the occurrence of avascular necrosis of the femoral epiphysis after nailing in adolescents is rather frequent. OBJECTIVE: The aim of this study was to assess iatrogenic soft tissue injuries at the site of nail insertion. MATERIALS AND METHODS: Nailing with a reamed AO universal femoral nail was performed on sixteen adult cadavers followed by dissection of the proximal part of the femur to assess possible damage to the soft tissues. Three entry portals were defined. (A) entry portal lateral to the junction of the neck and the greater trochanter; (B) entry portal at the base of the greater trochanter anterior to a line along the longitudinal axis of the femoral neck; and (C) entry portal at the base of the greater trochanter posterior to a line along the axis of the femoral neck (at the piriformis fossa). RESULTS: In Group A, partial avulsion of the piriformis and the obturator internus tendon were present in four and in one of five specimens, respectively. Group B showed injuries to the piriformis tendon in two and to the gluteus minimus tendon in one of four cases. In Group C, partial avulsion of the piriformis, obturator internus, and obturator externus tendon were encountered in five, six, and two of seven specimens, respectively. Anterior branches of the ramus profundus of the m.f.c.a. within the synovial fold were damaged in all of these cases. CONCLUSION: To select the best nail entry portal, the ease of nail insertion must be weighed against the resulting soft tissue damage at the site of insertion. The nail entry portal at the piriformis fossa, although geometrically ideal and most recommended, causes the most significant damage to muscle and tendons as well as to the blood supply to the femoral head. Therefore, even if reported only once, the occurrence of avascular necrosis of the femoral head after nailing in adults is a possible complication of this nail entry portal. The authors therefore prefer to avoid this entry portal in every case. The nail entry portal anterior to the longitudinal axis of the femoral neck, as in group B, although better with respect to the soft tissue damage, has the worst geometric and biomechanical disadvantages. The results of the current study favor the nail entry portal lateral at the greater trochanter as in Group A, which is equal to the entry portal B with respect to the soft tissue damage but allows introduction of the nail into the medullar cavity without difficulties.     

Results of femoral intramedullary nailing in patients who are obese versus those who are not obese: a prospective multicenter comparison study

OBJECTIVES: Antegrade femoral nailing through a piriformis fossa starting point in patients who are obese has been demonstrated to be problematic. Retrograde femoral nailing therefore has been advocated in this patient population, but little data exist to support such a recommendation. The purpose of this study was to evaluate and compare antegrade and retrograde femoral nailing technique in both patients who are and are not obese. DESIGN: Prospective, multicenter, nonrandomized, internal review board (IRB)-approved study. SETTING: Four Level 1 trauma centers. PATIENTS: Patients (151) with a femoral shaft fracture (OTA 32) treated with intramedullary nailing were studied. Thirty-two with a body mass index (BMI) of >or=30 comprised the obese group (OG), and 119 with a BMI of <30 comprised the nonobese group (NOG). Antegrade nailing was performed in 15 patients from the OG and 84 from the NOG. Retrograde nailing was performed in 17 patients from the OG and 35 from the NOG. INTERVENTION: Reamed intramedullary nailing of a femoral shaft fracture. MAIN OUTCOME MEASURES: Patient and fracture characteristics, operative time, fluoroscopy time, healing, complications, and functional outcome based on the lower extremity measure (LEM) were evaluated. RESULTS: Antegrade technique in the OG was associated with a 52% greater average operative time (94 minutes) compared with antegrade nailing in the NOG (62 minutes; P < 0.003). For retrograde nailing technique, there was no difference in the average operative time between the OG (67 minutes) and NOG (62 minutes; P = 0.51). Antegrade technique in the OG was associated with a 79% greater average radiation exposure time (247 seconds) compared with antegrade nailing in the NOG (135 seconds; P < 0.03). For retrograde nailing technique, average fluoroscopy time was similar between the OG (76 seconds) and the NOG (63 seconds; P = 0.44). Within the OG, antegrade nailing required 40% greater average operative time (94 minutes versus 67 minutes, P < 0.02) and more than 3 times more average fluoroscopy time (242 seconds versus 76 seconds, P < 0.002) than retrograde nailing. Thirty-eight patients from the original cohort were not available for follow-up. Of the 113 patients followed (average 9 months, range: 4 to 25 months), healing complications occurred similarly between the 2 groups, with 1 nonunion and 2 delayed unions in the OG (12%), and 3 nonunions and 9 delayed unions in the NOG (14%). CONCLUSIONS: This study provides evidence, in the form of decreased operative and radiation exposure times, to support the use of retrograde nailing technique for the treatment of femoral shaft fractures in patients who are obese. Also, antegrade nailing was found to require significantly more operative and radiation exposure time in the patient who is obese as opposed to the patients who is not obese. Although having similar baseline functional scores, patients who are obese recovered at a slower rate and more incompletely than patients who are not obese.     

Intramedullary nailing of femoral shaft fractures in children via the trochanter tip

Closed rigid intramedullary nailing of femoral shaft fractures in children has been associated with avascular necrosis of the femoral head. Avascular necrosis of the femoral head is thought to result from damage to the medial femoral circumflex artery by placing the nail through the piriformis fossa. The authors describe the early results of a technique in which the nail is placed through the tip of the greater trochanter, thus avoiding the piriformis fossa and possible damage to the medial circumflex artery. Between 1988 and 1995, the authors performed this procedure on 34 patients, who ranged in age from 10 years 2 months to 17 years 6 months. Followup time ranged from 1 month to 120 months. There were no infections, nonunions, rotational deformities, or implant failures. Twenty patients with open physes had a followup of 2 years or more. To date, no patient had avascular necrosis of the femoral head develop. The trochanteric tip entry point is recommended for closed rigid intramedullary nailing of femoral shaft fractures in children and adolescents.     

Marknagelung des Femurs mit einem helikalen Implantat (LFN®)

Objective

Antegrade femoral nailing through a greater trochanteric entry portal avoids damage to the proximal external rotators and to the ramus profundus of the medial femoral circumflex artery, furthermore eases insertion in adipose subjects. However a helical nail shape is necessary for this pathway because bending in two perpendicular planes has to be passed by the nail.

Indications

All femoral shaft fractures suitable for antegrade nailing (type 32-A/B/C). Additional femoral neck fractures (type 31-B) by using proximal Recon-interlocking screws.

Contraindications

The common contraindications for femoral nailing. In certain subtrochanteric fractures (Type 32-A/B) the proximal femoral nail may be favorable.

Surgical technique

General or spinal anesthesia. Supine position with flexion/abduction of the contralateral leg in order to facilitate fluoroscopy of the proximal femur in a true lateral view. Closed reduction of length and axis. Measurement of length and diameter of the nail using a radiolucent ruler. Dorsolateral approach to the greater trochanter. Insertion of the guide wire 10 mm lateral to the trochanteric tip (anteroposterior view) and in the middle third of the trochanter (lateral view). Reaming of the insertion point using a flexible reamer. If reaming of the entire medullary canal is desired, this should be done using a long intramedullary guide wire in combination with a long flexible reamer. Insertion of the nail starts in an anterior position and ends in a lateral position of the insertion instrument, so a 90° external rotation of the nail occurs during insertion. Proximal interlocking is performed using the guide of the insertion instrument. Check interfragmentary rotation. Distal interlocking using a radiolucent drill device.

Postoperative management

Depends on the fracture shape: stable interfragmentary support may allow early full weight bearing. Otherwise, reduced weight bearing is recommended for at least 6 weeks.

Results

In a prospective mulicentric study, 227 helical femoral nails were used for antegrade femoral nailing. Follow-up after 12 month was available in 74?%. Surgeons’ rating for ease of identifying entry site was excellent or good in 89?%. Functional and radiological results after 12 months do not prove significant benefits over conventional antegrade femoral nails.     

Intramedullary femoral nailing through the trochanteric fossa versus greater trochanter tip: a randomized controlled study with in-depth functional outcome results

Purpose  

In a level 1 university trauma center, an explorative randomized controlled study was performed to compare soft tissue damage and functional outcome after antegrade femoral nailing through a trochanteric fossa (also known as piriform fossa) entry point to a greater trochanter entry point in patients with a femoral shaft fracture.     

Soft tissue injury related to choice of entry point in antegrade femoral nailing: piriform fossa or greater trochanter tip

Intramedullary nailing through the piriform fossa results in some cases in loss of abduction strength and persistent pain. Nail insertion at the tip of the greater trochanter may be favourable. The aim of this study was to assess (possible) iatrogenic injury to the abductor and external rotator musculature, branches of the superior gluteal nerve and branches of the MFCA in relation to the two different entry points. In 10 fresh human cadaver femurs, five unreamed femoral nails (UFN) were inserted through the piriform fossa and five AO prototype nails (AFN) through the trochanteric tip. The iatrogenic injury at each nailing procedure was assessed. Various muscles and tendons, branches of the MFCA along with the hip joint capsule were injured or largely at risk during nail insertion through the piriform fossa. Most of these structures were not exposed during insertion through the trochanteric tip. The reported clinical morbidity after nailing through the piriform fossa may find its origin in direct soft tissue injury and may be reduced by choosing a lateral nail entry point.     

Anatomy of the greater femoral trochanter: clinical importance for intramedullary femoral nailing. Anatomic study of 100 cadaver specimens

Background Fossa piriformis is considered the correct point of entry for a straight femoral nail. A trochanteric overhang may make the access to fossa piriformis difficult. We investigated the anatomy of the trochanteric region, paying special attention to the entry point for antegrade intramedullary femoral nailing.

Methods and results We studied 100 cadaver specimens. In 63 specimens a shape with a free entry point was found, whereas in 37 cases the entry point was either half or fully covered. In 9 specimens the entry points could not be exactly located from a cranial aspect.

Interpretation The anatomic variations of the trochanteric sometimes make it difficult to identify the correct entry point for an intramedullary nail.     

The impact of antegrade intramedullary nailing start site using the SIGN nail in proximal femoral fractures: A prospective cohort study

IntroductionIn many low and middle-income countries (LMICs) SIGN nail is commonly used for antegrade femoral intramedullary (IM) nailing, using a start site either at the tip of the greater trochanter or piriformis fossa. While a correct start site is considered an essential technical step; few studies have evaluated the impact of using an erroneous start site. This is particularly relevant in settings with limited access to fluoroscopy to aid in creating a nail entry point. The purpose of this study was to evaluate the impact of antegrade SIGN IM nailing start site on radiographic alignment and health-related quality of life.MethodsIn this prospective cohort study, adult patients with proximal femur fractures (OTA 32, subtrochanteric zone) treated with antegrade IM SIGN nail at Muhimbili Orthopaedic Institute (MOI), Dar es Salaam, Tanzania were enrolled. Start site was determined on the immediate postoperative X-ray and was graded on a continuous scale based on distance of the IM nail center from the greater trochanteric tip. The primary outcome measurement was coronal alignment on the post-operative x-ray. The secondary outcomes were reoperation rates, RUST scores and EQ5D scores at one year follow-up.ResultsSeventy-nine patients were enrolled. 50 of them (63.3%) had complete data at 1 year and were included in the final data analysis. Of the fifty patients, nine (18%) had IM nails placed laterally, 26 (52%) medially and 15 (30%) directly over the tip of the greater trochanter. Compared to a start site at the tip or medial to the greater trochanter, a lateral start site was 9 times more likely to result in a varus malalignment (95% CI: 1.42–57.70, p = 0.021).ConclusionsLateral start site was associated with varus malalignment. Although lateral start site was not significantly associated with reoperation, varus deformity was associated with higher reoperation rates. Surgeons should consider avoiding a start site lateral to the tip of the greater trochanter or allow the nail to rotate to avoid malalignment when using the SIGN nail for proximal femur fractures.     

Greater trochanteric versus piriformis fossa entry nails for femur shaft fractures: Resolving the controversy

BackgroundIntramedullary nailing is the treatment of choice for shaft of femur fractures in adults. Antegrade nails involve entry through either piriformis fossa (PE) or greater trochanteric (GT) tip. The superiority of one entry point over the other is a matter of debate, and the present review was done to determine the same.Research questionIs GT entry for antegrade femur nailing superior to the PE for shaft femur fractures in adults?ObjectiveThe present systematic review was conducted to determine the superiority of one entry point over the other by comparing the outcome parameters like operative time, exposure to fluoroscopy, mal-unions, non unions, abductor weakness, varus malalignment and Harris Hip scores (HHS).MethodologyThree databases of PubMed, EMBASE and SCOPUS were searched for relevant articles that directly compared GT with PE for nailing in shaft femur fractures in adults.ResultsWe analysed a total of 9 studies published between the years 2011–2017. There were 5 retrospective and 4 prospective studies, out of which 3 were randomised. The total number of patients was 256 in GT group and 460 in PE group.OutcomesThere was significant superiority of GT entry over PE on meta analysis; lesser operation time: standard mean difference (SMD): -21.01; lesser exposure to fluoroscopy : SMD: 36.36; lesser incidence of abductor weakness: Odd’s ratio (OR): 14.35; better functional outcome (HHS): SMD -2.48.ConclusionGT entry nails are superior to PE nails for treating shaft of femur fractures in adults. They have a shorter learning curve and better functional outcomes, however the rates of union are comparable in both.     

Muscle function and functional outcome following standard antegrade reamed intramedullary nailing of isolated femoral shaft fractures

OBJECTIVE: To evaluate the functional outcomes and long-term effects on muscle strength of femoral shaft fractures treated with intramedullary (IM) antegrade nailing using a standard piriformis start point. DESIGN: Retrospective Outcome Study. SETTING: Tertiary Level Teaching Hospital and Referral Centre for the Province of British Columbia. PATIENTS/PARTICIPANTS: Twenty-one patients (7 female, 14 male; mean age 34.5 years, range 16-56 years) with isolated femoral shaft fractures who were treated with standard antegrade reamed interlocking IM nailing and who had a minimum 1-year follow-up were identified through the Orthopaedic Trauma Database. All patients had isokinetic muscle testing of their hip abductors, hip extensors, and knee extensors using the KinCom muscle testing machine. Of the patients, 10 underwent formal gait lab analysis. All of the patients answered a questionnaire and completed the Short Form (SF)-36 and Musculoskeletal Functional Assessment outcome measures. INTERVENTION: Antegrade reamed interlocking IM nailing of femoral shaft fractures using a standard trochanteric fossa (also referred to as piriformis fossa) starting point. MAIN OUTCOME MEASUREMENTS: Examination of muscle strength, using 2 different objective measures (KinCom and gait analysis). The KinCom muscle testing machine was used for isokinetic muscle testing of hip abductors, hip extensors, and knee extensors. Outcome questionnaires were used to evaluate function (Musculoskeletal Functional Assessment) and general health (SF-36). RESULTS: Isokinetic muscle testing showed a statistically significant lower peak torque generation by the hip abductors (P=0.003) and hip extensors (P=0.046) from the uninjured contralateral side. The gait lab analysis did not show important changes in gait pattern. Scores for the SF-36 were 51.77+/-7.55 and 53.73+/-8.70. Scores for the Short Musculoskeletal Functional Assessment (S-MFA) were 7.74 and 8.66. Both scores did not indicate any significant disability. CONCLUSIONS: Antegrade reamed interlocking IM nailing of femoral shaft fractures using a standard trochanteric fossa starting point is associated with a mild hip abductor muscle-strength deficit. Gait pattern returns to normal following femoral shaft fracture treated with this technique, and functional outcomes are good.     

Short reconstruction nail for intertrochanteric fracture: does it really fit Asian feature?

Background  

The Trigen short reconstruction trochanteric antegrade nail (TAN) is considered most suitable for the small skeletons of Asian patients. We have evaluated the results of TAN for intertrochanteric fractures in Asian patients.     

逆行和顺行置髓内钉治疗股骨干骨折的疗效比较

目的比较逆行和顺行置髓内钉治疗股骨干骨折的临床疗效。方法将57例股骨干骨折患者按置钉方式的不同分为对照组(经大转子顺行置髓内钉治疗,25例)和观察组(经股骨髁逆行置髓内钉治疗,32例)。比较两组术中透视次数、手术时间、术中出血量、骨折愈合时间、术后6个月Harris评分。结果患者均获得随访,时间7~12个月。手术时间、术中出血量观察组明显短(少)于对照组(P<0.05);术中透视次数、骨折愈合时间以及术后6个月Harris评分两组比较差异均无统计学意义(P>0.05)。结论逆行和顺行置髓内钉治疗股骨干骨折均能取得满意的临床疗效,但逆行置髓内钉具有手术操作简单、无需使用牵引床、手术时间短、术中出血量少等优点,更利于基层医院使用。     

股骨粗隆下骨折手术治疗进展

股骨粗隆下区骨折是髋关节周围骨折中最难处理的一种骨折类型,多由高能量创伤所致的粉碎性骨折。非手术治疗有较高的畸形愈合、不愈合以及其他并发症发生率,因而,粗隆下骨折多主张手术治疗。Russell-Taylor分类方法临床较常用,有利于指导内固定方法的选择。对于小粗隆以下平面的骨折,采用标准的交锁髓内钉较理想。骨折波及到小粗隆但梨状窝未累及时,选用头髓钉或95°角钢板可取得满意效果。对于大粗隆骨折并累及梨状窝时,采用滑行钉器械固定较好。DHS器械不适宜用于粗隆下骨折的治疗。     

Anatomy of the Greater Trochanteric ‘Bald Spot’: A Potential Portal for Abductor Sparing Femoral Nailing?

Soft tissue injury occurs when using a piriformis portal for femoral nailing. Standard trochanteric portals also can injure the gluteus medius and external rotator tendons, which may be a source of hip pain after nailing. On the lateral facet of the greater trochanter, a “bald spot” may exist that is devoid of tendon insertion. This may be a potential portal for intramedullary nail insertion. We defined the dimensions and location of this region. Cadaveric specimens were dissected to expose the tendon insertions on the greater trochanter. A computer navigation system was used with a stylus and bone morphing to determine the tendon insertions and bald spot anatomy. The greater trochanteric bald spot is covered by the subgluteus medius bursa and has no tendon insertions. Its center lies 11 mm distal to the tip of the greater trochanter and 5 mm anterior to the midline. The shape is ellipsoid with a diameter of 21 mm. This region is large enough to accommodate the size of most nailing system reamers without tendon footprint infringement. Use of this modified entry site may reduce soft tissue injury with nailing procedures and minimize subsequent hip pain. One or more of the authors (MJG, DGL) have received funding from Synthes. Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.     

Prospective comparison of retrograde and antegrade femoral intramedullary nailing

OBJECTIVE: To prospectively compare the results, function, and complications of antegrade and retrograde femoral nailing for femoral shaft fractures. DESIGN: Prospective, randomized. SETTING: Urban Level 1 trauma center. PATIENTS: One hundred consecutive femoral shaft fractures. Fifty-four nails inserted retrograde and forty-six inserted antegrade. INTERVENTION: Ten-millimeter antegrade or retrograde nail inserted for a femoral shaft fracture after reaming. OUTCOME MEASUREMENTS: A comparison of the outcomes after antegrade and retrograde nailing of the femur. Data were collected for analysis on comminution, set-up and starting point times, open grade, location of fracture, injury severity score, body mass index, time to union, knee pain and motion, hip and thigh pain, and nail to intramedullary canal diameter difference. A linear regression model was employed. RESULTS: Knee motion was 120 degrees in all but one knee in each group. The antegrade nailed femurs healed faster than those treated retrograde (A = 14.4, R = 18.1 weeks, p = 0.0496). More patients required dynamization for union in the retrograde insertion group (17 percent versus 5 percent, p = 0.10, NS). In a linear regression model, a nail-to-canal-diameter difference and retrograde nailing had an association with an increased time to union. Knee pain was equal in both groups; however, thigh pain was higher in the antegrade group (p = 0.0108). All of the antegrade nailed femurs healed (100 percent), and 98 percent (one nonunion) of the retrograde femurs healed after secondary procedures. CONCLUSIONS: Both antegrade and retrograde nailing yielded high union rates. Each insertion technique has its own advantages and disadvantages. The two insertion modes appear to be relatively equal for the treatment of femoral shaft fractures.     

Retrograde entry portal for cephalomedullary nailing in difficult subtrochanteric fractures

An entry point medial to the tip of the greater trochanter is considered optimal for antegrade femur nailing. The deforming forces in a subtrochanteric fracture often make it difficult to establish a perfect entry point during antegrade cephalomedullary nailing. To overcome this problem, we report a simple technique of making a retrograde entry portal for select difficult subtrochanteric fractures. The technique was used in 12 subtrochanteric fractures. Our indications were morbid obesity, revision nailing and atypical fractures. The technique involves creating a nail entry portal through the fracture from distal to proximal taking advantage of the abducted proximal fragment. Fracture reduction and nail insertion then proceeds in a standard manner. Additional reaming of the thick endosteal lateral cortex through the fracture was performed in atypical fractures. Satisfactory fracture reduction was achieved in all patients and 11 out of the 12 fractures united in the series. 1 patient developed an infected nonunion and was considered failure of treatment. The retrograde entry portal is a valuable alternative method that can be considered in nailing of difficult subtrochanteric fractures to establish an ideal entry point and nail trajectory.     

Can Fluoroscopy-based Computer Navigation Improve Entry Point Selection for Intramedullary Nailing of Femur Fractures?

Background

The entry point is crucial to an accurate reduction in femoral nailing. Fluoroscopy-based navigation was developed to aid in reducing femur fractures and selecting entry points.

Questions/purposes

We asked: (1) Can the piriformis fossa (PF) and tip of the greater trochanter (TT) be identified with high reproducibility? (2) What is the range of nonneutral images clinically acceptable for entry point selection? (3) Does navigation improve accuracy and precision of landmarking the TT and PF? And (4) does off-angle fluoroscopy within the acceptable range affect landmark accuracy?

Methods

Three orthopaedic surgeons digitized the PF and TT under direct visualization on 10 cadaveric femurs, quantifying the reproducibility of the targeted PF and TT landmarks. Arcs of acceptable AP and lateral images of each femur were acquired in increments of 5° with a C-arm. An experienced orthopaedic surgeon rejected or accepted images for entry point selection by qualitatively assessing the relative positions and sizes of the greater trochanter, lesser trochanter, and femoral neck. Entry points were identified on each image using fluoroscopy and navigation. Hierarchical linear modeling was used to compare accuracy and precision between navigation and fluoroscopy and the effects of image angle.

Results

A 29° average arc of acceptable images was found. Reproducibility of the target landmarks for the PF and TT under direct visualization was excellent. Navigation had similar accuracy to fluoroscopy for PF localization but less for TT. Navigation increased precision compared to fluoroscopy for both PF and TT. Image angle affected accuracy of the PF and TT under fluoroscopy and navigation.

Conclusions

Nonorthogonal images reduce accuracy of PF and TT identification with both navigation and fluoroscopy. Navigation increased precision but decreased accuracy and cannot overcome inaccuracies induced by nonorthogonal images.