Total hip arthroplasty and femoral nail lengthening for hip dysplasia and limb-length discrepancy

Leg Length Discrepancy in Total Hip Arthroplasty: Not All Discrepancies Are Created Equal

The original review article, published in 2006, describing leg length discrepancy after total hip arthroplasty commented that "equal leg length should not be guaranteed." There has been considerable advancement in surgical technique and technology over the past decade, allowing surgeons to "hit the target" much more consistently. In this interval paper, we review leg length discrepancy and introduce some technologies designed to mitigate this complication. In addition, we present challenging clinical scenarios in which perceived leg length may differ from true leg length and how these can be addressed with proper workup and surgical execution.

Retrograde Femoral Lengthening Below a Total Hip Arthroplasty

BACKGROUND

Limb length discrepancy (LLD) after total hip arthroplasty (THA) is a common occurrence and can lead to back pain, disordered gait, and decreased functional outcomes. Femoral lengthening ipsilateral to a THA using a retrograde motorized intramedullary lengthening nail (MILN) is a hip-sparing option for limb equalization. There has been little published on the technique and results of this method.

METHODS

We retrospectively reviewed all patients at our institution who underwent unilateral femoral lengthening using a retrograde MILN ipsilateral and distal to a THA between April 2016 and June 2022. We describe the technique and considerations for this procedure in detail and report the patient demographic variables, etiology and magnitude of LLD, concomitant deformity, knee range of motion, time to union, and all adverse events and complications.

RESULTS

Eleven lengthening procedures were included in this cohort. Etiology for LLD included osteonecrosis (4); postinfection (3); and one each of post-trauma, congenital deficiency, hip dysplasia, and iatrogenic discrepancy secondary to the index THA procedure. The mean lengthening was 35.7 ± 14.7 mm (range 20 to 70 mm) with a lengthening index of 1.5 ± 1.2 months until union per cm of lengthening. Complications included two patients who required reamed exchange nailing to achieve union and one interprosthetic fracture treated with removal of the MILN and plate fixation. No adverse effects on THA function were documented.

CONCLUSION

Femur lengthening using a retrograde MILN ipsilateral to a THA is a safe and reliable hip-sparing option for post-THA limb length equalization.

Total Hip Replacement and Femoral Nail Lengthening for Hip Dysplasia and Limb Length Discrepancy: A Literature Review

Developmental dysplasia of the hip (DDH) is a serious condition resulting in inadequate acetabular development, distorted bone configuration, and substantially altered hip biomechanics. An extensive leg length discrepancy (LLD) is commonly encountered in such cases, making a total hip arthroplasty (THA) procedure extremely challenging. Although good results in terms of patients' satisfaction, implant survival rates and overall improved quality of life have been reported, complication rates are considerably higher than primary THA procedures performed for idiopathic osteoarthritis. Reconstructing a dysplastic hip arthrosis and equalizing a preexisting LLD is a technically demanding procedure that is associated with significant bone and soft tissue complications. Intramedullary lengthening through motorized nails has become increasingly popular to address difficult cases with extensive LLD following THA in recent years. However, limited data on femoral lengthening procedures implemented following THA are available considering complications, radiological results, and patient-reported outcomes following staged THA and subsequent femoral lengthening using a femoral magnetically-driven intramedullary lengthening nail. We performed a literature review of the past 10 years in PubMed using the terms neglected hip dislocation, DDH, THA, and intramedullary lengthening nail as keywords. A total amount of eight cases addressing LLD through a telescoping intramedullary nail following THA in DDH have been reported in recent literature. All eight patients underwent primary THA for DDH followed by the implantation of the intramedullary lengthening nail. The mean THA was lengthened by 28.9 mm (from 13.0 to 45.0). The mean time for nail implantation after THA was 11.1 months (from 3.5 to 21). The mean time for lengthening per day through the nail was 0.94 mm (from 0.65 to 1.0) from 26 days to 70 days, and the mean lengthening through the nail was 37.6 mm (from 24.0 to 70.0). Good union and consolidation rates were reported by the authors, while there were no complications. The intramedullary distraction osteogenesis method with a telescopic rod can be an effective method to manage leg length discrepancies while avoiding soft tissue complications in challenging cases of DDH.

Reduction of High Hip Dislocation With a Distraction Nail and Arthroplasty (Preliminary Results of a Novel Technique)

A novel distraction technique is described for total hip arthroplasty in symptomatic high hip dislocation (Crowe IV) combining an intramedullary motorized lengthening nail with a pelvic support plate to gradually stretch hip soft tissues (distalization) and performing total hip arthroplasty with the cup in the primary acetabulum. Twelve patients (15 hips) were identified in a retrospective study via chart review. Medical records and radiographs were reviewed for details of the initial case parameters, surgical details, magnitude of distalization, duration of treatment, outcomes, and complications. Followed by an average of 67.4 mm of distalization, nearly anatomical cup placement, and equal leg length were achieved in all patients. During distalization, pain level was low with acceptable range of motion. One unplanned surgery and no complications with long-term sequelae occurred.

An Update on the Intramedullary Implant in Limb Lengthening: A Quinquennial Review Part 2: Extending Surgical Indications and Further Innovation

The use of the intramedullary lengthening nail has gained in popularity over the last decade. The reduction in complications associated with the use of external fixators and excellent patient outcomes has resulted in the largest change in management of limb length discrepancy since the concept of distraction osteogenesis was accepted by the Western world in the 1980s. Success following "simple" limb lengthening has led to surgeons extending the indications for the lengthening nail, including different bone segments, lengthening associated with potential joint instability and lengthening combined with acute deformity correction. There has been a drive for further implant modification to reduce complications, and enable full weight bearing during the lengthening process. This would offer the opportunity to consider simultaneous limb lengthening. The aim of this review is to evaluate the literature published over the last five years and highlight important learning points and technical tips for these expanding indications.

Staged reconstruction of unilateral neglected hip dislocation through total hip arthroplasty and subsequent intramedullary femoral lengthening

Background and purpose

Total hip arthroplasty (THA) is a successful approach to treat unilateral symptomatic neglected hip dislocation (NHD). However, the extensive leg length discrepancy (LLD) can hereby only be partially corrected. In case of residual LLD of more than 2 cm, subsequent femoral lengthening can be considered.

Patients/material/methods

Retrospective analysis of clinical data and radiographs of five patients (age 38.1 (28–51) years) with unilateral NHD who underwent THA with (n  = 3) or without (n = 2) subtrochanteric shortening osteotomy (SSO) and secondary intramedullary femoral lengthening through a retrograde magnetically-driven lengthening nail (follow-up 18.4 (15–27) months).

Results

LLD was 51.0 (45–60) mm before and 37.0 (30–45) mm after THA. Delayed bone union at one SSO site healed after revision with autologous bone grafting and plate fixation. Subsequent lengthening led to leg length equalisation in all patients. Complete consolidation was documented in all lengthened segments.

Conclusion

Staged reconstruction via THA and secondary femoral lengthening can successfully be used to reconstruct the hip joint and equalise LLD. The specific anatomical conditions have to be taken into consideration when planning treatment, and patients ought to be closely monitored.

Systematic review of complications with externally controlled motorized intramedullary bone lengthening nails (FITBONE and PRECICE) in 983 segments

Background and purpose - In recent years motorized intramedullary lengthening nails have become increasingly popular. Complications are heterogeneously reported in small case series and therefore we made a systematic review of complications occurring in lower limb lengthening with externally controlled motorized intramedullary bone lengthening nails.Methods - We performed a systematic search in PubMed, EMBASE, and the Cochrane Library with medical subject headings: Bone Nails, Bone Lengthening, and PRECICE and FITBONE nails. Complications were graded on severity and origin.Results - The search identified 952 articles; 116 were full text screened, and 41 were included in the final analysis. 983 segments were lengthened in 782 patients (age 8-74 years). The distribution of nails was: 214 FITBONE, 747 PRECICE, 22 either FITBONE or PRECICE. Indications for lengthening were: 208 congenital shortening, 305 acquired limb shortening, 111 short stature, 158 with unidentified etiology. We identified 332 complications (34% of segments): Type I (minimal intervention) in 11% of segments; Type II (substantial change in treatment plan) in 15% of segments; Type IIIA (failure to achieve goal) in 5% of segments; and Type IIIB (new pathology or permanent sequelae) in 3% of segments. Device and bone complications were the most frequent.Interpretation - The overall risk of complications was 1 complication for every 3 segments lengthened. In 1 of every 4 segments, complications had a major impact leading to substantial change in treatment, failure to achieve lengthening goal, introduction of a new pathology, or permanent sequelae. However, as no standardized reporting method for complications exists, the true complication rates might be different.

Intramedullary Bone Lengthening Following Preceding Hip Surgery-A Case Series

Limb length discrepancy (LLD) is a common problem after joint-preserving hip surgeries, hip dysplasia, and hip deformities. Limping, pain, sciatica, paresthesia, and hip instability are common clinical findings and may necessitate limb-lengthening procedures. The study included five patients (two female and three male, mean age of 28 years (20–49; SD: 12)) with symptomatic limb length discrepancy greater than 2.5 cm (mean: 3.6 cm) after total hip arthroplasty (THA), hip dysplasia, or post-traumatic hip surgery. They underwent either ipsi- or contralateral intramedullary limb-lengthening surgeries using the PRECICE™ telescopic nail. All patients achieved complete bone healing and correction of the pelvic obliquity after intramedullary lengthening. None of the patients had a loss of proximal or distal joint motion. The mean distraction-consolidation time (DCT) was 3.8 months, the distraction index (DI) 0.7 mm/day, the lengthening index (LI) 1.8 months/cm, the consolidation index (CI) 49.2 days/cm, the healing index (HI) 1.1 months/cm, and the modified healing index (HI*) 34 days/cm. Intramedullary limb lengthening after LLD in cases of hip dysplasia, hip deformity, and various kinds of hip surgery is a useful and safe procedure in young patients to achieve equal limb length. No functional impairment of the preceded hip surgery was seen.

Hip-Sparing Equalization Procedures for Leg-Length Discrepancy After Total Hip Arthroplasty: A Retrospective Case Series

BACKGROUND

Leg-length discrepancy (LLD) after primary THA is not uncommon. Little is known, however, about the role of hip-sparing procedures for equalization of LLD after THA.

QUESTIONS/PURPOSES

The aim of this study is to report our experiences with these techniques in patients presenting at one institution over a 10-year period.

METHODS

We retrospectively reviewed records at one institution to find patients who had sought surgical treatment for LLD after THA between January 2007 and August 2017. Patients who had LLD related to conditions other than the THA, such as bone loss or traumatic defects, were excluded. We recorded the time after THA, laterality, and LLD. Assessment of LLD was performed using clinical and radiographic examinations. Patient demographics and true LLD were recorded, as were prior conservative treatment, equalization procedure performed, final leg length after equalization surgery, time to healing, and complications.

RESULTS

After exclusion of patients with LLD related to other causes, eight patients in whom conservative treatment had failed and who had undergone hip-sparing leg-length equalization surgery were included in the study. The average age was 44.6 years (range, 18 to 66 years). Seven of the patients were female. The pre-operative mean LLD was 3.1 cm (range 1.5 to 7 cm). In those who were long after THA, ipsilateral (THA-side) shortening of femur with a retrograde intramedullary nail (IMN; n = 1) or with a plate (n = 1) was performed. In those who were short after THA, ipsilateral femur lengthening with retrograde Precice nails (n = 2), ipsilateral tibial lengthening with Precice nails (n = 2), or contralateral femur shortening with a retrograde IMN (n = 2) was performed. The average time to full consolidation or union was 6.6 months (range, 2 to 19 months). Two patients had delayed union. All patients but one were satisfied with final results.

CONCLUSION

We believe that hip-sparing equalization procedures can be part of the treatment algorithm of LLD after THA. These advancements in the field are promising and might expand the indications of lengthening and equalization procedures to include LLD after THA.