Soft tissue anatomy around the hip and its implications for choice of entry point in antegrade femoral nailing

Cooled Radiofrequency Ablation of the Trochanteric Branch of the Nervus Femoralis to Treat Greater Trochanteric Pain Syndrome

OBJECTIVE

Greater trochanteric pain syndrome is a common cause of lateral hip pain. Corticosteroid injections are commonly utilized as non-surgical interventions, however they are not effective for all patients. This technical case report describes a method for treating greater trochanteric pain syndrome by utilizing cooled radiofrequency ablation.

METHODS

The trochanteric branch of the nervus femoralis is identified as providing sensory innervation to the greater trochanter and its surrounding structures. We have identified fluoroscopic targets to block the nerve and perform cooled radiofrequency ablation. We present two patient cases which demonstrated significant pain relief of greater trochanteric pain syndrome with this treatment.

CONCLUSIONS

Cooled radiofrequency ablation of the trochanteric branch of the nervus femoralis is a potential treatment for greater trochanteric pain syndrome. This procedure provides a potential steroid-sparing interventional treatment based on reproducible fluoroscopic landmarks.

Does using different entrance points for intramedullary nails affect clinical outcomes for femoral shaft fractures? A retrospective clinical comparative study

OBJECTIVE

We examined the clinical and radiological outcomes of femoral shaft fractures treated with two different intramedullary nail designs using either greater trochanteric or trochanteric fossa entrance.

METHODS

The medical records of patients undergoing operations for a shaft fracture either with a nail with trochanteric entrance or trochanteric fossa entrance were retrospectively reviewed. Inclusion criteria were: having the necessary medical records including radiographic images and follow-up data, at least 12 months of follow-up, skeletal maturity (≥16 years of age) not having osteoporosis (≤60 years of age). Exclusion criteria were: pathological fractures, fragility fractures, fractures that extend to hip or knee joint capsule, lack of enough medical data, less than 12 months of follow up, and patients yet to reach skeletal maturity.

RESULTS

A total of 65 patients (67 femur fractures) were treated with intramedullary nails using a trochanteric fossa entrance (TFE) and 21 patients (23 femur fractures) were treated with nails using a greater trochanteric entrance (GTE). No statistically significant differences were evident between groups in terms of union time, blood loss, need for implant removal, implant failure, or revision operation. However, the duration of postoperative hospitalization was significantly shorter in the GTE nail group and the need for open reduction of the fracture was less common in these patients. Although there were no significant differences between groups in terms of complications and union among isthmal and infra-isthmal fractures, malreduction and iatrogenic fractures were more common with the use of GTE nails for treatment of supra-isthmal fractures.

CONCLUSION

Use of intramedullary nails via both GTE and TFE were safe and efficient for the treatment of isthmal and infra-isthmal fractures. However, varus malalignments associated with iatrogenic fractures were more common with trochanteric entrance nails. Together, our results show that the use of nails via TFE may represent a safer option for surgical treatment of supra-isthmal fractures.

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

BACKGROUND

Intramedullary 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 QUESTION

Is GT entry for antegrade femur nailing superior to the PE for shaft femur fractures in adults?

OBJECTIVE

The 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).

METHODOLOGY

Three 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.

RESULTS

We 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.

OUTCOMES

There 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.

CONCLUSION

GT 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.

Robotic technique improves entry point alignment for intramedullary nailing of femur fractures compared to the conventional technique: a cadaveric study

We aimed to test whether a robotic technique would offer more accurate access to the proximal femoral medullary cavity for insertion of an intramedullary nail compared to the conventional manual technique. The medullary cavity of ten femur specimens was accessed in a conventional fashion using fluoroscopic control. In ten additional femur specimens, ISO-C 3D scans were obtained and a computer program calculated the ideal location of the cavity opening based on the trajectory of the medullary canal. In both techniques, the surgeon opened the cavity using a drill and inserted a radiopaque tube that matched the diameter of the cavity. The mean difference in angle between the proximal opening and the medullary canal in the shaft of the femur was calculated for both groups. Robotic cavity opening was more accurate than the manual technique, with a mean difference in trajectory between the proximal opening and the shaft canal of 2.0° (95% CI 0.6°-3.5°) compared to a mean difference of 4.3° (95% CI 2.11°-6.48°) using the manual technique (P = 0.0218). The robotic technique was more accurate than the manual procedure for identifying the optimal location for opening the medullary canal for insertion of an intramedullary nail. Additional advantages may include a reduction in total radiation exposure, as only one ISO-C 3D scan is needed, as opposed to multiple radiographs when using the manual technique.

Antegrade versus retrograde nailing techniques and trochanteric versus piriformis intramedullary nailing entry points for femoral shaft fractures: a systematic review and meta-analysis

BACKGROUND

There are several different techniques commonly used to perform intramedullary (IM) nailing of the femur to fix femoral fractures. We sought to identify significant differences in outcomes of studies comparing 1) trochanteric and piriformis entry and 2) antegrade and retrograde entry in IM nailing of the femur.

METHODS

We searched MEDLINE, Cochrane and Embase databases and the Orthopaedic Trauma Association and American Academy of Orthopaedic Surgeons websites for comparative studies published from inception to November 2015. Criteria used to select articles for detailed review included use of antegrade and retrograde entry point or use of trochanteric and piriformis entry point for IM nailing of the femur in adult patients. Functional and technical outcomes were extracted from accepted studies.

RESULTS

We identified 483 potential studies, of which 52 were eligible. Of these, we included 13 publications and 2 abstracts (2 level I, 7 level II and 6 level III studies). Trochanteric entry significantly reduced operative duration by 14 min compared with piriformis entry (p = 0.030). Retrograde nailing had a greater risk of postoperative knee pain than antegrade nailing (p = 0.05). On the other hand, antegrade nailing had significantly more postoperative hip pain (p = 0.003) and heterotopic ossification (p < 0.001) than retrograde nailing. No significant differences in functional outcomes were observed.

CONCLUSION

Although some significant differences were found, the varying quality of studies made recommendation difficult. Our meta-analysis did not confirm superiority of either antegrade over retrograde or trochanteric over piriformis entry for IM nailing of the femur.

LEVEL OF EVIDENCE

Level III therapeutic.

An Anatomic Study of the Greater Trochanter Starting Point for Intramedullary Nailing in the Skeletally Immature

BACKGROUND

Trochanteric entry femoral nails have been increasing in popularity in the pediatric population for stabilization in fractures and osteotomies. The proper position for entry point in the coronal plane has been well studied; however, the sagittal plane in the pediatric population has not yet been well characterized.

METHODS

Eighty-eight cadaveric femora aged 8 to 20 years were studied in an apparent neck-shaft angle (ANSA) position, with distal condyles flat on the surface, and a true neck-shaft angle (TNSA) position, with internal rotation to neutralize femoral anteversion. Anterior and lateral offset were measured on lateral and anteroposterior photographs, respectively, as the perpendicular distance from the greater trochanter apex to the center of the intramedullary canal. The effect of rotational position (ANSA vs. TNSA) of the proximal femur was compared using the intraclass correlation coefficient for anterior and lateral offset. Correlations between age, demographics, anteversion, and greater trochanter morphology with anterior and lateral offset were evaluated with multiple regression analysis.

RESULTS

The mean age was 15.8±3.8 years. The mean anterior displacement of the trochanteric apex was 4.8±3.0 and 4.6±3.2 mm in the ANSA and TNSA positions, respectively. The mean lateral displacement was 10.6±4.2 and 9.7±4.0 mm in the ANSA and TNSA positions, respectively. The intraclass coefficient for anterior offset in the ANSA versus TNSA position was 0.704 and 0.900 for lateral offset. Change was minimal for anterior offset in the ANSA and TNSA positions versus age (standardized beta values 0.240, 0.241, respectively). There was a significant correlation with increasing lateral offset in the ANSA and TNSA positions with increasing age (standardized beta values 0.500, 0.385 respectively).

CONCLUSIONS

In the pediatric population, the tip of the greater trochanter is consistently anterior by approximately 5 mm. The mean lateral displacement was approximately 10 mm and increased with increasing age.

CLINICAL RELEVANCE

Nail entry at the pediatric greater trochanter apex would likely result in anterior placement. We recommend inserting the guidewire 5 mm posterior to the apex of the trochanter and confirming coronal and sagittal position with fluoroscopy.

Where is the true location of the femoral piriform fossa?

OBJECTIVE

To analyze knowledge of the anatomic location of the piriform fossa using a questionnaire with anatomic figures.

MATERIALS AND METHODS

Participants taking AO Trauma Brasil courses were requested to complete a questionnaire containing a photograph of the superior surface and a photograph of the lateral surface of the femur and answer a question asking which of four numbered points corresponded to the piriform fossa.

RESULTS

Just 4.5% of respondents correctly chose point 2 (the piriform fossa) in both images, while 75.4% of respondents chose point 4 (the trochanteric fossa) as the correct anatomic structure. The subset of 4th-year residents' answers was significantly different from those of the other subsets, with 7.5% of correct answers.

CONCLUSIONS

The low rate of correct answers indicates a tendency for the respondents to be influenced by illustrations in text books or examples in scientific publications that indicate the site of the piriform fossa incorrectly. Interest in the specialty of traumatology is possibly the reason why the subset of 4th-year residents had a better- than-average rate of correct answers.

An appraisal of the short lateral rotators of the hip joint

The short lateral rotators (piriformis, obturator internus, superior and inferior gemelli, obturator internus, and quadratus femoris) are functionally important muscles, significantly contributing to hip joint stability. They act as "postural muscles", holding the femoral head in the acetabulum during hip movements, thus are frequently monitored in gait analysis and for muscle rehabilitation post-injury. Despite the need to precisely identify and repair these muscles for stability postoperatively, clinical complications have resulted from the inadequate and inconsistent understanding of their morphological and functional anatomy. Furthermore, the short lateral rotators have complex entheses (osteotendinous insertions on bone) and may be subject to overuse injury in sport. This study aims to review the reported morphology of the short lateral rotators in order to ascertain whether discrepancies exist in our understanding of these muscles, and if further investigation is required to aid in gait analysis, clinical management of hip pathologies, and prevention of overuse injuries. Following a literature search strategy, 59 primary references were retrieved from three databases, with additional 26 anatomical textbooks selected for critical evaluation. Numerous inaccuracies and inconsistencies in the anatomical descriptions of the attachments, patterns of innervation and actions exist, and often insufficiently supported by primary findings. There is also a paucity of information regarding the architectural pattern of the muscles, which would be useful in clarifying the function of these dynamic stabilizers of the hip joint. A better anatomical understanding of these muscles will better inform hip reconstruction and lead to improved surgical outcomes by reducing post-operative complications.

The effect of antegrade femoral nailing on femoral head perfusion: a comparison of piriformis fossa and trochanteric entry points

INTRODUCTION

Piriformis fossa entry antegrade femoral nailing is a common method for stabilizing diaphyseal femur fractures. However, clinically significant complications such as chronic hip pain, hip abductor weakness, heterotopic ossification and femoral head osteonecrosis have been reported. A recent cadaveric study found that piriformis entry nailing damaged either the deep branch of the medial femoral circumflex artery (MFCA) or its distal superior retinacular artery branches in 100% of specimens and therefore recommended against its use. However, no study has quantitatively assessed the effect of different femoral entry points on femoral head perfusion.

MATERIALS AND METHODS

Twelve fresh-frozen cadaveric lower extremity specimens were randomly allocated to either piriformis fossa or trochanteric entry nailing using a 13-mm reamer. The contralateral hip served as an internal matched control. All specimens subsequently underwent gadolinium-enhanced fat-suppressed gradient-echo sequence MRI to assess femoral head perfusion. Gross dissection was also performed to assess MFCA integrity and distance to the opening reamer path.

RESULTS

MRI quantification analysis revealed near full femoral head perfusion with no significant difference between the piriformis and trochanteric starting points (95 vs. 97%, p = 0.94). There was no observed damage to the deep MFCA in either group. The mean distance from the reamer path to the deep MFCA was 3.2 mm in the piriformis group compared to 18.5 mm in the trochanteric group (p = 0.001). Additionally, there was a significantly greater number of mean terminal superior retinacular vessels damaged by the opening reamer in the piriformis cohort (1 vs. 0; p = 0.007).

CONCLUSIONS

No statistically significant difference in femoral head perfusion was found between the two groups. Therefore, we cannot recommend against the use of piriformis entry femoral nails. However, we caution against multiple errant starting point attempts and recommend meticulous soft tissue protection during the procedure.

An anatomical study of the entry point in the greater trochanter for intramedullary nailing

Malpositioning of the trochanteric entry point during the introduction of an intramedullary nail may cause iatrogenic fracture or malreduction. Although the optimal point of insertion in the coronal plane has been well described, positioning in the sagittal plane is poorly defined. The paired femora from 374 cadavers were placed both in the anatomical position and in internal rotation to neutralise femoral anteversion. A marker was placed at the apparent apex of the greater trochanter, and the lateral and anterior offsets from the axis of the femoral shaft were measured on anteroposterior and lateral photographs. Greater trochanteric morphology and trochanteric overhang were graded. The mean anterior offset of the apex of the trochanter relative to the axis of the femoral shaft was 5.1 mm (sd 4.0) and 4.6 mm (sd 4.2) for the anatomical and neutralised positions, respectively. The mean lateral offset of the apex was 7.1 mm (sd 4.6) and 6.4 mm (sd 4.6), respectively. Placement of the entry position at the apex of the greater trochanter in the anteroposterior view does not reliably centre an intramedullary nail in the sagittal plane. Based on our findings, the site of insertion should be about 5 mm posterior to the apex of the trochanter to allow for its anterior offset.

[Femoral nailing using a helical nail shape (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.

Trochanteric fossa or piriform fossa of the femur: time for standardised terminology?

Piriform fossa, trochanteric fossa and greater trochanteric tip have each been described as entry points for antegrade femoral nailing. However, the terminology used for these entry points is confusing. The accuracy of the entry point nomenclature in published text and illustrations was recorded in this review study. The trochanteric fossa, a deep depression at the base of the femoral neck is indicated as 'piriform fossa' in the vast majority of the publications. Other publications indicate the insertion site of the tendon of the piriformis muscle on the greater trochanteric tip as 'piriform fossa'. As a result of recurrent terminology error and consistent reproductions of it, the recommended entry point in literature is confusing and seems to need standardisation. The piriform fossa does not appear to exist in the femoral region. The trochanteric fossa is the standard entry point which most surgeons recommend for facilitating a standard straight intramedullary nail, as is in line with the medullary canal. The greater trochanteric tip is the lateral entry point for intramedullary nails with a proximal lateral bend.

Risk of injury to the superior gluteal nerve when using a proximal incision for insertion of a piriformis-entry reamed femoral intramedullary nail: a cadaveric study

BACKGROUND

This cadaveric study evaluated the risk of injury to the superior gluteal nerve when a proximal incision site is used for insertion of an antegrade, reamed femoral intramedullary nail into the piriformis fossa. Based on prior anatomical studies, our hypothesis is that the use of a proximal incision site for intramedullary nail insertion will consistently injure the superior gluteal nerve.

METHODS

A reamed femoral intramedullary nail was inserted through a piriformis fossa entry site in six pairs of fresh-frozen cadaver femora. The specimens were randomized to two groups: reaming of the femoral canal with or without a protective sleeve. Damage to the superior gluteal nerve was evaluated by means of layered dissection of specimens. Damage to any part(s) of the superior gluteal nerve was recorded, and the distances between the path of the instrumentation and nail and the branches of the superior gluteal nerve were measured.

RESULTS

A "spray" nerve pattern of the superior gluteal nerve was present in all twelve specimens. The average distance and standard deviation between the most superior branch of the superior gluteal nerve and the instrumentation and nail path was 17.75 ± 8.58 mm. The average distance between the most inferior branch of the superior gluteal nerve and the instrumentation and nail path was 22.39 ± 10.52 mm. There were no significant differences between the two groups. There were no injuries to any part of the superior gluteal nerve regardless of whether or not a protective sleeve was used.

CONCLUSIONS

This anatomic study demonstrated that the superior gluteal nerve is not at risk for injury when a proximal incision site is used to place a reamed intramedullary nail into the piriformis fossa.

[Experiences with a helical femoral nail (LFN®). A multicenter study]

INTRODUCTION

Antegrade intramedullary nailing is the method of choice in most femoral shaft fractures. The trochanteric entry portal of classic femoral nails is in close proximity to the piriformis tendon, the gluteus minimus tendon, the obturator tendons, and the medial femoral circumflex artery. Nail insertion lateral to the tip of the greater trochanter may be more favorable but needs the use of a helical implant.

MATERIAL AND METHODS

Measurement of the reamer pathway through an entry point lateral to the superior trochanteric border was performed with a three-dimensional motion tracking sensor in human cadaveric femurs. These results provided a scientific rationale for the design of a helical femoral nail (LFN®). In a prospective multicenter study a total of 227 femoral shaft fractures were treated by nailing with the LFN. Patients were followed at 3 months (n=193) and 12 months (n=167).

RESULTS

The ease of defining the entry point and inserting the nail was rated as"very good and good" by 90% of the surgeons. Intraoperative technical complications included incomplete reduction (14%), additional iatrogenic fractures (6%), and difficulties in interlocking (3.5%). At the 1-year follow-up, delayed unions were seen in 10%, secondary loss of reduction in 3%, and deep infection in 1.8% of the patients. Angular malalignment of more than 5° was seen in 5%, mostly in valgus. A normal walking capacity was seen in 68% and normal active hip flexion in 45%.

CONCLUSION

The results obtained in this study during 1 year do not provide evidence for an advantage of the LFN over conventional antegrade femoral nails.

Analysis of the sensory innervations of the greater trochanter for improving the treatment of greater trochanteric pain syndrome

In medical practice, greater trochanteric pain syndrome has an incidence of 5.6 per 1,000 adults per year, and affects up to 25% of patients with knee osteoarthritis and low back pain in industrialized nations. It also occurs as a complication after total hip arthroplasty. Different etiologies of the pain syndrome have been discussed, but an exact cause remains unknown. The purpose of this study was to obtain a better understanding of the sensory innervations of the greater trochanter in attempt to improve the treatment of this syndrome. Therefore, we dissected the gluteal region of seven adult and one fetal formalin fixed cadavers, and both macroscopic and microscopic examination was performed. We found a small sensory nerve supply to the periosteum and bursae of the greater trochanter. This nerve is a branch of the n. femoralis and accompanies the arteria and vena circumflexa femoris medialis and their trochanteric branches to the greater trochanter. This nerve enters the periosteum of the greater trochanter directly caudal to the tendon of the inferior gemellus muscle. This new anatomical information may be helpful in improving therapy, such as interventional denervation of the greater trochanter or anatomically guided injections with corticosteroids and local anesthetics.

Functional outcome after antegrade femoral nailing: a comparison of trochanteric fossa versus tip of greater trochanter entry point

OBJECTIVES

This study was performed to explore the relationship between entry point-related soft tissue damage in antegrade femoral nailing and the functional outcome in patients with a proximal third femoral shaft fracture.

DESIGN

Retrospective clinical trial.

SETTING

Level I university trauma center.

PATIENTS

Seventeen patients with a high femoral shaft fracture treated with an antegrade femoral nail joined the study.

INTERVENTION

Nine patients with an Unreamed Femoral Nail (UFN; Synthes, Bettlach, Switzerland) inserted at the trochanteric fossa and eight patients with a long Proximal Femoral Nail (PFN; Synthes) inserted at the tip of the greater trochanter.

MAIN OUTCOME MEASUREMENTS

Pain, gait, nerve, and muscle function along with endurance.

RESULTS

Five patients with a UFN had a positive Trendelenburg sign and a reinnervated superior gluteal nerve after initial injury of the nerve at operation. None of these findings occurred in the long PFN group (P = 0.01). Isokinetic measurements showed diminished abduction as well as external rotator function in the UFN group rather than in the long PFN group. Leg endurance was significantly lower in patients with a UFN.

CONCLUSIONS

Compared with the trochanteric fossa, femoral nailing through the greater trochanter tip may decrease the risk of damage to the superior gluteal nerve and intraoperative damage to the muscular apparatus of the hip region, resulting in some improved muscle function. Therefore, a lateral entry point may be a rational alternative for conventional nailing through the trochanteric fossa.

Is there a standard trochanteric entry site for nailing of subtrochanteric femur fractures?

OBJECTIVES

To evaluate the variability of the ideal trochanteric starting point as a possible cause for malreduction of subtrochanteric fractures and to analyze the accuracy of contralateral templating to predict correct entry site.

METHODS

Standardized anteroposterior pelvis radiographs of 50 patients were evaluated by two independent reviewers. Patients with advanced osteoarthritis, severe hip deformity, and radiographs with asymmetric hip rotation were excluded. Ideal nail entry site was established using a template for a trochanteric nail with a 6° proximal bend. The distance from the greater trochanteric tip to the ideal nail entry site was measured. Additionally, offset of the greater trochanter tip from the femoral longitudinal axis was measured. Interobserver reliability and accuracy of contralateral templating were evaluated.

RESULTS

The ideal entry point ranged from 16 mm medial to 8 mm lateral to the trochanteric tip (mean, 3 mm medial; standard deviation, 5 mm). In 70% of patients, the ideal entry point was medial to and in 23% lateral to the tip of the greater trochanter. Ideal entry points were located within 2 mm of the trochanteric tip in 29% and within 4 mm in 44% of patients. The location of the ideal entry point relative to the trochanteric tip had a weak correlation with patient height and neck shaft angle (r: -0.23 and r: -0.35, respectively). Interobserver reliability and agreement between left and right side measurements were strong (intraclass correlation coefficient: >0.94 and >0.88, P < 0.001, respectively). The mean measurement differences between sides was 0 mm (95% confidence interval: -1 to 1). Greater trochanter offset averaged 15 mm (range, 5-26 mm; standard deviation: 5) on the right and 15 mm (range, 5-25 mm; standard deviation: 5.1) on the left (P = 0.95).

CONCLUSION

A high degree of variability exists for the ideal trochanteric entry site. The trochanteric tip represents the ideal starting point in only the minority of cases. Preoperative contralateral templating provides an accurate means for establishing a patient-specific entry point to minimize fracture malreduction.

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.

MATERIALS AND METHODS

Nineteen patients were enrolled and randomly assigned to two nail insertion groups; ten patients were treated with an Unreamed Femoral Nail(®) (UFN, Synthes(®), Solothurn, Switzerland) inserted at the trochanteric fossa and nine patients were treated with an Antegrade Femoral Nail(®) (AFN, Synthes(®), Solothurn, Switzerland) inserted at the tip of the greater trochanter. The main outcome measures were pain, gait, nerve and muscle function, along with endurance. Magnetic resonance imaging (MRI), electromyography (EMG), and Cybex isokinetic testings were performed at, respectively, 2 and 6 weeks and at a minimum of 12 months after surgery.

RESULTS

The MRI and EMG showed, in both groups, signs of iatrogenic abductor musculature lesions (four in the UFN group and four in the AFN group) and superior gluteal nerve injury (five in the UFN group and four in the AFN group). The isokinetic measurements and the patient-reported outcomes showed moderate reduction in abduction strength and endurance, as well as functional impairment with slight to moderate interference with daily life in both groups, with no appreciable differences between the groups.

CONCLUSIONS

Anatomical localization of the entry point seems to be important for per-operative soft tissue damage and subsequent functional impairment. However, the results of this study did not show appreciable differences between femoral nailing through the greater trochanter tip and nailing through the trochanteric fossa.