Derotational osteotomies utilizing a trochanteric-start intramedullary nail

Outcomes of percutaneous femoral derotational osteotomy in pediatric patients

Background

Percutaneous femoral derotational osteotomies are performed in both adult and pediatric patients. There is little published on the outcomes after femoral derotational osteotomy in pediatric patients.

Methods

A retrospective cohort study of pediatric patients treated with percutaneous femoral derotational osteotomy by one of two surgeons between 2016 and 2022 was performed. Data collected included patient demographics; surgical indications; femoral version; tibial torsion; magnitude of rotational correction; complications; time to hardware removal; pre-operative and post-operative patient-reported outcome scores, including Limb Deformity-Scoliosis Research Society and Patient-Reported Outcomes Measurement Information System; and time to consolidation. Descriptive statistics were used to summarize the data and t tests used to compare means.

Results

Thirty-one femoral derotational osteotomies in 19 patients were included with an average age of 14.7 (9-17) years. The average rotational correction was 21.5° ± 6.4° (10°-40°). The average length of follow-up was 17.9 ± 6.7 months. There were no instances of nonunion, joint stiffness, or nerve injury. No patients returned to the operating room for additional surgeries other than routine hardware removal. There were no cases of avascular necrosis of the femoral head. Of the 19 patients, 8 completed both a pre-operative and post-operative survey set. There were significant improvements in the Limb Deformity-Scoliosis Research Society Self-Image/Appearance sub-category and the Patient-Reported Outcomes Measurement Information System Physical Function sub-category.

Conclusion

Femoral derotational osteotomy using a percutaneous drill hole technique with antegrade trochanteric entry femoral nail is safe in the pediatric population and improves self-image in patients with symptomatic femoral version abnormalities.

Percutaneous Femoral Derotational Osteotomy in the Skeletally Immature Patient

Percutaneous femoral derotational osteotomies are performed in both adult and pediatric patients for excessive symptomatic femoral anteversion or retroversion^1,2. The aim of the procedure is to correct version abnormalities with use of a minimally invasive technique³.

Description

This is a percutaneous procedure that involves creation of femoral drill holes at the osteotomy site prior to reaming the canal⁴. External fixator pins are placed proximal and distal to the osteotomy site prior to completing the osteotomy. These pins are derotational markers for the surgeon and act to hold the correction with use of an external fixator while the interlocking screws are being placed. The pins are placed at a degree of divergence that is equal to the degree of intended derotation so that the pins will become parallel in the axial plane following derotation of the femur. The percutaneous osteotomy is then completed with use of an osteotome, and the trochanteric entry nail is passed across the osteotomy site while correcting rotation. Once rotation is fully corrected and the pins are parallel, the external fixator is placed to hold the rotation and interlocking screws are placed.

Alternatives

Nonoperative alternatives to this procedure include physical therapy for gait training and strengthening as well as modalities to address hip and knee pain that may be associated with version abnormalities. Although physical therapy is often prescribed, it must be noted that excess version is a fixed osseous structural pathology that therapy cannot address. Additionally, compensatory mechanisms that may be taught to improve gait and walk with a neutral foot progression angle may exacerbate hip or knee pathology as a result of the underlying version abnormality. Surgical alternatives include derotational osteotomies of the proximal or distal aspects of the femur with use of an open technique with plate fixation, as opposed to an intramedullary nail following percutaneous diaphyseal osteotomy as presented here¹. Additionally, an open technique with intramedullary nail fixation may be performed⁵.

Rationale

Excessive anteversion can cause both hip and knee symptoms, including hip pain, instability, labral and psoas pathology, and patellofemoral instability⁶. Excessive retroversion can cause impingement between the femoral neck and acetabulum, which results in pathology of the labrum and articular cartilage⁷. Additionally, abnormalities of version often lead to gait disturbances with frequent tripping and difficulty running⁸. Children with femoral version abnormalities have limited remodeling potential after age 8³. A derotational osteotomy may be performed to correct symptomatic excess femoral version in an older child or adolescent.

Expected Outcomes

The patient may be weight-bearing as tolerated with upper-extremity assistance immediately following the procedure. The osteotomy typically heals between 6 and 12 weeks, and the patient may return to activities as tolerated once the osteotomy is healed. Gordon et al. described the outcomes of a similar technique for femoral derotational osteotomy in skeletally immature patients with excessive femoral anteversion³. The study retrospectively reviewed the results of the technique in 13 patients and 21 limbs at a minimum follow-up of 1 year. All patients complained of tripping and gait abnormalities preoperatively. All patients noted gait improvement, and no intraoperative or postoperative complications were reported. Healing of the osteotomy occurred at a mean of 6 weeks postoperatively. No patient developed osteonecrosis. We routinely remove hardware in skeletally immature patients approximately 1 year postoperatively. Complications are rare and include hardware irritation, infection, nonunion, and neurovascular injury.

Important Tips

Preoperative planning is critical for this procedure, and the surgeon should know the intended degree of derotation, the location of the osteotomy relative to the greater trochanter, the length of the nail, and the approximate diameter of the nail prior to entering the operating room.Percutaneous bicortical femoral drill holes are created at the site of the osteotomy prior to reaming to allow for egress of reamings and bone marrow elements at the osteotomy site, which serve as autograft and stimulate bone healing. Additionally, the drill holes provide ventilation to prevent excessive intramedullary pressure during reaming^9-11.External fixator pins are placed proximal and distal to the osteotomy prior to completion of the osteotomy to allow for rotational assessment after completion of the osteotomy. Placing these pins bicortically so that they are secure in the bone and ensuring that the divergence is correct for the intended amount of derotation is critical in this procedure because once the osteotomy is complete, the pins are the only markers of rotation the surgeon has to guide the correction.An external fixator is helpful in holding the femur at the intended degree of derotation during placement of the interlocking screws.

Acronyms & Abbreviations

ROM = range of motionCT = computed tomographyMRI = magnetic resonance imagingAP = anteroposteriorGT = greater trochanterAV = anteversionER = external rotationIR = internal rotationA = anteriorP = posteriorM = medialL = lateralXR = X-rayProx = proximalEx fix = external fixatorWBAT = weight-bearing as toleratedBLE = bilateral lower extremitiesDVT = deep venous thrombosisPT = physical therapyppx = prophylaxisAVN = avascular necrosis (osteonecrosis).

Femoral Derotational Osteotomies

PURPOSE OF REVIEW

Femoral derotational osteotomies are performed to correct residual symptomatic increased femoral torsion in adolescents and adults. Typical indications are anterior knee pain caused by patellar maltracking and patellofemoral instability. There is still no consensus as to what the correct indication is and which surgical techniques lead to the best outcomes in performing a femoral derotational osteotomy.

RECENT FINDINGS

Good early clinical outcomes have been reported. However, long-term studies and data on return to play are lacking. Surgery often is performed according to the surgeon's experience. There is no evidence to support decisions regarding surgical technique or level of osteotomy. Femoral derotational osteotomy is the treatment of choice in patients with symptomatic excessive anteversion and torsional malalignment of the femur. Multiple techniques have shown good clinical results with high patient satisfaction. Future studies however must focus on radiographic and clinical assessment to understand different subtypes of torsional deformity and its implication on operative therapy.

Trochanteric Entry for Femoral Lengthening Nails in Children: Is It Safe?

BACKGROUND

Antegrade intramedullary (IM) nailing for skeletally immature femur fractures can damage the capital femoral epiphysis blood supply, leading to avascular necrosis (AVN) of the femoral head. Reported AVN rates are 2% for piriformis entry and 1.4% for trochanteric entry. None of previous reports described IM lengthening nails for limb lengthening procedures. We have used self-lengthening telescopic nails with a proximal Herzog bend and standard trochanteric entry for femoral lengthening in children. The purpose of this study is to determine whether trochanteric entry IM lengthening nails can be used safely (no AVN or proximal femoral deformity) in the skeletally immature femur.

METHODS

A retrospective review was performed between 2004 and 2014 to determine all skeletally immature patients younger than 18 years of age who had a reamed IM lengthening nail inserted through the greater trochanter, with at least 1-year follow-up.

RESULTS

Thirty-one femurs were lengthened in 28 patients (17 males and 11 females). The etiology was congenital femoral deficiency (10), achondroplasia (6), post-traumatic (5), hemihypertrophy (3), Ollier disease (2), and miscellaneous (5). An attending surgeon was present for all procedures. Mean age at time of surgery was 12.9 years (range, 7 to 17 y). Mean follow-up was 3.5 years (range, 1.4 to 9 y). The average amount of lengthening was 5.4 cm (range, 3 to 6.7 cm). Twenty-four nails were 10.7 mm in diameter. Seven nails were 12.5 mm in diameter. Intramedullary skeletal kinetic distractor was used in 18 femurs and PRECICE in 13 femurs. Ten segments (7 intramedullary skeletal kinetic distractor; 3 PRECICE) experienced 13 complications. None of the patients developed AVN or proximal femoral deformity.

CONCLUSIONS

IM lengthening nails inserted through the greater trochanter may be utilized in skeletally immature patients without increased risk of AVN of the femoral head or proximal femoral deformity. Larger trials would be helpful to confirm our hypothesis. We recommend careful surgical technique with liberal use of the image intensifier to avoid trauma to the femoral head blood supply.

LEVEL OF EVIDENCE

Level IV-therapeutic.