Constant inhibition in congenital lower extremity shortening: does it begin in utero?

BACKGROUND: Limb-length discrepancy (LLD) in children with congenital lower extremity shortening is constant in proportion from birth to skeletal maturity (known as constant inhibition), but its developmental pattern in utero is unknown. The popular prenatal multiplier method to predict LLD at birth assumes constant inhibition in utero to be true. Verifying the in utero developmental pattern of LLD, and thus confirming the validity of the prenatal multiplier method, is crucial for meaningful prenatal parental counseling. OBJECTIVE: To elucidate the in utero developmental pattern of LLD in fetuses with congenital lower extremity shortening. MATERIALS AND METHODS: Clinical indications for 3,605 lower extremity radiographs performed on infants (<1 year old) at a large tertiary hospital over a 17-year period were reviewed. Inclusion criteria were (1) diagnosis of congenital lower extremity shortening, (2) bilateral lower limb postnatal radiographs documenting LLD and (3) fetal ultrasound (US) documenting LLD. Available measurements of femoral, tibial and fibular lengths on fetal US and postnatal radiographs were collected. Prenatal and postnatal length ratios of shorter-to-longer bones were calculated and compared. RESULTS: Eighteen infants met inclusion criteria. Diagnoses were proximal focal femoral deficiency=4, congenital short femur=2, tibial hemimelia=3, posteromedial tibial bowing=6 and fibular hemimelia=3. The correlations between postnatal and prenatal length ratios were high for the femur, tibia and fibula (R>0.98, P<0.0001). The relative differences in the postnatal and prenatal length ratios of these bones were small (|average|<0.026, standard deviation <0.068). CONCLUSION: Our data indicate that the postnatal and prenatal length ratios were equivalent, supporting the constant inhibition pattern of LLD in utero, thus validating the prenatal multiplier method for predicting LLD.

Cutis marmorata telangiectatica congenita and major lower limb asymmetry.

A 39-week-old male newborn presented at birth with atrophic erythematous and purpuric skin lesions, in a typical right-sided segmental distribution. Lesions were persistent and unaffected by rewarming in the postpartum period. Postnatal echocardiogram showed a predominance of the right cavities and an upper atrial septal defect. Cerebral and abdominal ultrasound were normal along with ophthalmological examination. On follow-up, lower limbs asymmetry was noted. The right lower limb was shorter in length and had a smaller diameter. At 6 months, the right lower limb was 1.5 cm shorter than the left, most likely related to nutritive vessels malformations. The discrepancy was even more pronounced at the age of 9 months. This leg-length asymmetry can lead to severe functional limitations in the future.

Avascular Necrosis in the Contralateral Hip in Patients With Congenital Femoral Deficiency: A Report of 3 Cases.

BACKGROUND: Congenital femoral deficiency is an uncommon clinical entity. We report 3 patients who developed avascular necrosis of the hip in the long (normal) leg during longitudinal observation and/or treatment of congenital femoral deficiency. METHODS: Patients were identified in limb length discrepancy clinic and their charts were retrospectively reviewed for clinical and radiographic data collection. RESULTS: We describe the occurrence of idiopathic avascular necrosis in the normal limb in patients being followed for limb length discrepancy. CONCLUSIONS: Although no conclusion could be drawn about the etiology of the avascular necrosis, we describe a previously undocumented relationship between congenital femoral deficiency and avascular necrosis in the contralateral hip. This occurred in our congenital femoral deficiency population at a rate higher than expected compared with published incidences of avascular necrosis of the hip in children. LEVEL OF EVIDENCE: Level IV-case series.

Prediction of Clinically Significant Leg-Length Discrepancy in Congenital Disorders.

Leg-length discrepancy greater than 2 to 2.5 cm can potentially have an adverse effect on our walking and standing mechanisms and requires proper correction involving surgical treatment. However, for minor leg-length discrepancy in childhood, decision making for the indications for and timing of epiphysiodesis is difficult because of unpredictable final discrepancy. The purpose of this study was to analyze longitudinal changes of minor leg-length discrepancy in congenital disorders and to determine earlier predictive values for the clinically significant discrepancy. Twenty-one patients with congenital disorders who had minor leg-length discrepancy less than 2 cm at the first presentation were retrospectively evaluated. The patients were divided into 2 groups according to leg-length discrepancy at latest follow-up: the significant group (n=11) had 25 mm or more of leg-length discrepancy and the minor group (n=10) had less than 25 mm of leg-length discrepancy. The authors evaluated longitudinal changes of leg-length discrepancy within the first 10 years by mixed-effects regression model. All patients showed monotonically increasing leg-length discrepancy with age, except for 2 (neurofibromatosis type 1 and macrodactyly of the foot) who demonstrated fluctuating leg-length discrepancy. Mean annual rate of leg-length discrepancy change in the significant group was 2.1 mm across the first decade of life and was significantly larger than that in the minor group (difference in slope, 1.3 mm; P<.0001). In minor leg-length discrepancy associated with congenital disorders, the incidence of clinically significant leg-length discrepancy can be predictable by the annual rate of leg-length discrepancy change in the first decade of life.

Common Patterns of Congenital Lower Extremity Shortening: Diagnosis, Classification, and Follow-up.

Congenital lower limb shortening is a group of relatively rare, heterogeneous disorders. Proximal focal femoral deficiency (PFFD) and fibular hemimelia (FH) are the most common pathologic entities in this disease spectrum. PFFD is characterized by variable degrees of shortening or absence of the femoral head, with associated dysplasia of the acetabulum and femoral shaft. FH ranges from mild hypoplasia to complete absence of the fibula with variable shortening of the tibia. The development of the lower limb requires complex and precise gene interactions. Although the etiologies of PFFD and FH remain unknown, there is a strong association between the two disorders. Associated congenital defects in the lower extremity are found in more than 50% of patients with PFFD, ipsilateral FH being the most common. FH also has a strong association with shortening and bowing of the tibia and with foot deformities such as absence of the lateral rays of the foot. Early diagnosis and radiologic classification of these abnormalities are imperative for appropriate management and surgical planning. Plain radiography remains the main diagnostic imaging modality for both PFFD and FH, and appropriate description of the osseous abnormalities seen on radiographs allows accurate classification, prognostic evaluation, and surgical planning. Minor malformations may commonly be misdiagnosed.

Femoral lengthening with a motorized intramedullary nail.

PURPOSE: We assessed whether an intramedullary lengthening device would reduce the problems normally associated with the external fixation technique. We also wanted to determine whether it is a reliable construct for limb lengthening and deformity correction in the femur. PATIENTS AND METHODS: We conducted a matched-pair comparison of 30 femoral lengthenings, 15 with a motorized intramedullary nail (the nail group) and 15 lengthenings with an external ring fixator (the fixator group). The patients were matched based on age, sex, amount of lengthening, and the etiology of leg length discrepancy. Mean lengthening was 35 (25-55) mm in the nail group and 38 (15-75) mm in the fixator group. Outcome measures were: lengthening and alignment achieved, consolidation index, knee range of motion (ROM), and complications. RESULTS: The pairs in this matched-pair study were similar in terms of age, sex, diagnosis, and amount of lengthening. The planned amount of lengthening was achieved in all patients in both groups and axis correction was considered sufficient. The mean radiographic consolidation index in the nail group, at 1.5 (0.9-3.0) months/cm, was better than the mean value for the fixator group (1.9 (0.9-3.4) months/cm) (p = 0.01). Knee ROM was better in the nail group during the lengthening, 6 weeks after lengthening was completed, and 6 months after lengthening was completed (p < 0.001). A larger number of complications were observed in the fixator group than in the nail group. INTERPRETATION: A lengthening nail may be superior to external fixation in femoral lengthening, when the anatomical conditions and the complexity of the deformity allow the use of an intramedullary nail.

Internal lengthening device for congenital femoral deficiency and fibular hemimelia.

BACKGROUND: Patients with congenital limb shortening can present with joint instability, soft tissue contractures, and significant leg length discrepancy. Classically, lengthening is done with external fixation, which can result in scarring, pin site infection, loss of motion, and pain. We therefore developed an alternative to this approach, a new, controllable, internal lengthening device for patients with congenital limb shortening. QUESTIONS/PURPOSES: We evaluated this device in terms of (1) healing index, (2) complications, (3) accuracy of the device's external controller, and (4) adjacent-joint ROM. METHODS: Between January 2012 and May 2013, we treated 66 patients for congenital limb shortening, of whom 21 were treated using this device. During this period, general indications for using the device were patients with leg length discrepancies of 2 cm or more, with intramedullary canals able to withstand rods of at least 12.5-mm diameter and 230-mm length, without active infection in the affected bone, able to comply with the need for frequent lengthening, and without metal allergies or an implanted pacemaker. We included only those patients who had completed their course of treatment and were currently fully weightbearing, leaving 18 patients (21 bone segments) available for followup at a minimum of 6 months after limb lengthening (mean, 14 months; range, 6-22 months). Mean age was 19 years (range, 9-49 years). Sixteen femurs and five tibias were lengthened a mean of 4.4 cm (range, 2.1-6.5 cm). Mean distraction index was 1.0 mm/day (range, 0.5-1.8 mm/day). Healing index, complications, device accuracy, and ROM were recorded. To date, 10 of the 21 devices have been removed. This was typically done 12-24 months after insertion when the bone was solidly healed on all four cortices. RESULTS: Mean healing index was 0.91 months/cm (range, 0.2-2.0 months/cm). There were seven complications requiring an additional unplanned surgery, including one hip flexion contracture, three femurs with delayed healing, one tibia with delayed healing, one hip subluxation/dislocation, and one knee subluxation. The external controller was accurate as programmed and actual lengthening amounts were consistent. ROMs of the hip, knee, and ankle were essentially maintained. CONCLUSIONS: This device is completely internal, allowing for satisfactory joint motion during treatment in most patients. Lengthening was achieved in an accurate, controlled manner, and all patients reached their goal length. Complications remain a concern, as is the case with all approaches to this complex patient population. Both future comparative studies and longer-term followup are needed. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Treatment of congenital leg length discrepancies in children using an Ilizarov external fixator: a comparative study.

The purpose of this study was to evaluate the influence of intramedullary (IM) alignment used in combination with an Ilizarov external fixation on the healing index (HI) and lengthening index (LI) in the treatment of congenital leg length discrepancies (LLD). This study included 35patients aged from 3.5 to 19 (average age 10.73) who underwent thl egalisation procedure using an Ilizarov external fixator. We compared the duration of the external fixator application, LLD, HI and LI between two groups of children: children in Group I underwent limb lengthening by the conventional llizarov technique using an Ilizarov external fixator alone, and children in Group II underwent a combination of Ilizarov technique and intramedullary alignment with two Kirschner wires, introduced through two mini-incisions. We found significant differences between the two groups of patients for duration of external fixator application and HI. Patients with congeni- tal LLD treated with combined method of treatment had benefit from intramedullary alignment due to its better outcome.

Limb lengthening and peripheral nerve function-factors associated with deterioration of conduction.

BACKGROUND: and purpose Limb lengthening is performed for a diverse range of orthopedic problems. A high rate of complications has been reported in these patients, which include motor and sensory loss as a result of nerve damage. We investigated the effect of limb lengthening on peripheral nerve function. PATIENTS AND METHODS: 36 patients underwent electrophysiological testing at 3 points: (1) preoperatively, (2) after application of external fixator/corticotomy but before lengthening, and (3) after lengthening. The limb-length discrepancy was due to a congenital etiology (n = 19), a growth disturbance (n = 9), or a traumatic etiology (n = 8). RESULTS: 2 of the traumatic etiology patients had significant changes evident on electrophysiological testing preoperatively. They both deteriorated further with lengthening. 7 of the 21 patients studied showed deterioration in nerve function after lengthening, but not postoperatively, indicating that this was due to the lengthening process and not to the surgical procedure. All of these patients had a congenital etiology for their leg-length discrepancy. INTERPRETATION: As detailed electrophysiological tests were carried out before surgery, after surgery but before lengthening, and finally after completion of lengthening, it was possible to distinguish between the effects of the operation and the effects of lengthening on nerve function. The results indicate that the etiology, site (femur or tibia), and nerve (common peroneal or tibial) had a bearing on the risk of nerve injury and that these factors had a far greater effect than the total amount of lengthening.

Guided growth for the treatment of moderate leg-length discrepancy.

The purpose of this study was to evaluate the effectiveness and complication rate of guided growth for the treatment of patients with a moderate leg-length discrepancy. The authors retrospectively reviewed all patients treated with guided growth for a moderate leg-length discrepancy at their institution between October 2004 and December 2010. Thirty-four patients met the inclusion criteria from an initial cohort of 105 patients. All patients were followed until screw removal or maturity occurred. Nine patients had a developmental leg-length discrepancy, and 25 had a congenital leg-length discrepancy. Average age was 12.6 years (range, 7-16 years). Average leg-length discrepancies, as measured on standing long-leg radiographs from the top of the pelvis, the top of the femoral heads, and the center of the ankle to the top of the femoral heads, were 22, 19, and 17 mm, respectively. Average discrepancies at screw removal or maturity were 13, 10, and 11 mm, respectively. Twenty of 33 patients had a leg-length discrepancy of less than 1 cm at maturity or screw removal. The leg-length discrepancy change in patients who underwent guided growth of the tibia was minimal. Leg-length discrepancies in patients who underwent guided growth of the femur or both the femur and the tibia changed by an average of 10 mm. One patient had a mechanical axis change greater than 1 zone, and 1 patient required treatment for angular deformity after being treated for a leg-length discrepancy. Guided growth is a safe and effective technique for treating moderate leg-length discrepancies.

Long-term follow-up of Van Nes rotationplasty in patients with congenital proximal focal femoral deficiency.

Van Nes rotationplasty may be used for patients with congenital proximal focal femoral deficiency (PFFD). The lower limb is rotated to use the ankle and foot as a functional knee joint within a prosthesis. A small series of cases was investigated to determine the long-term outcome. At a mean of 21.5 years (11 to 45) after their rotationplasty, a total of 12 prosthetic patients completed the Short-Form (SF)-36, Faces Pain Scale-Revised, Harris hip score, Oswestry back pain score and Prosthetic Evaluation Questionnaires, as did 12 age- and gender-matched normal control participants. A physical examination and gait analysis, computerised dynamic posturography (CDP), and timed 'Up & Go' testing was also completed. Wilcoxon Signed rank test was used to compare each PFFD patient with a matched control participant with false discovery rate of 5%. There were no differences between the groups in overall health and well-being on the SF-36. Significant differences were seen in gait parameters in the PFFD group. Using CDP, the PFFD group had reduced symmetry in stance, and reduced end point and maximum excursions. Patients who had undergone Van Nes rotationplasty had a high level of function and quality of life at long-term follow-up, but presented with significant differences in gait and posture compared with the control group.

Long-term follow-up of congenital distal tibiofibular diastasis: a report of two female patients.

Congenital diastasis of the inferior tibiofibular joint is an extremely rare variant of dysplastic tibial anomaly, which is usually associated with significant shortening of the lower leg and ipsilateral foot deformity due to talus incarceration in the distal tibiofibular mortise. The purpose of this study was to present the long-term results of reconstructive treatment and the functional outcome after a follow-up of 11-16 years. The principles of extremity preservation and reconstruction with the Ilizarov frame have shown a stable ankle joint, a plantigrade foot, and fully independent outdoor ambulation in both patients at the final follow-up. We concluded that amputation should not be performed under this condition.

Hip dislocation during lengthening of congenital short femur.

Hip dislocation is a serious but rarely reported complication of femoral lengthening in congenital short femora. We report a retrospective series of three hip dislocations that occurred during lengthening, analyze the factors contributing to the dislocation, and discuss the treatment of this difficult problem. The average lengthening achieved was 9 cm. We found progressive acetabular dysplasia and decreasing center edge angle. Closed reduction failed. Treatment included soft tissue release, open reduction with femoral shortening, and acetabular procedures. At a mean follow-up of 4.4 years, two patients had a good modified Mckay score and a modified Severin score of 3. Excessive lengthening should be avoided.

Tibial hemimelia in one of the identical twins.

Tibial hemimelia, a rare congenital anomaly, is characterized by deficiency of the tibia with relatively intact fibula. The incidence of congenital deficiency of the tibia is approximately 1 per 1 million live births. The percentage of monozygotic twins is 0.8% of all newborns. Therefore, the occurrence of tibial hemimelia in monozygotic twins is 1 case per 125 million. The purpose of this article is to present a case of identical twins, in which 1 had tibial hemimelia, a double metatarsal bone and preaxial polydactyly and the other had no alterations. The patient that was affected had an anomaly in the left leg and foot. She had 7 fingers in her left foot and a left duplicated great toe. Her legs had a 3-cm difference in length, rigid inversion, adduction of feet, and severe bowing. A roentgenogram showed right tibial hemimelia with intact fibula corresponding to Jones type 3 and the first metacarpo was duplicated with a proximal osseus synostosis. Karyotyping confirmed that the twins were monozygotic. Only 1 of the identical twins had tibial hemimelia, a double metatarsal bone, and preaxial polydactyly. Congenital defects may result from aberrations in the developmental stage, the growth stage, or both. Hemimelia may result from a primary failure to form an anlage, or a primary failure to chronologically synthesize collagen. This case shows that tibial hemimelia can have variable phenotypic manifestations.

Distal focal femoral deficiency.

This report represents an interesting case of a rare distal focal femoral deficiency with a complication of hip dislocation. The deformity at the distal femur was erroneously given an initial diagnosis of proximal focal femoral deficiency, and we believe that other similar patients have been given this incorrect diagnosis. Additional reports of such patients will allow further identification of associated pathology. This study describes the features of distal focal femoral deficiency, potential orthopaedic concerns, and proposes a classification scheme for this pathology.

Femoral lengthening over elastic stable intramedullary nailing in children using the monolateral external fixator.

The authors report preliminary results of femoral lengthening performed with monolateral external fixation over elastic stable intramedullary nailing in children. Seven femoral lengthenings were performed in six patients, at a mean age at surgery of 6.6 years (range 1.5-12 years). All lengthenings were performed due to limb length discrepancy (congenital hypoplasia in four patients, growth arrest secondary to neonatal infective osteoarthritis in one, type II sacral agenesis in one). In six cases the elastic nails realised a bipolar ascending construct, in one case a descending construct. Cases were reviewed at a mean time from removal of external fixator of 34.2 months (range 15-75 months). The mean lengthening obtained was 4.8 cm (range 3.8-6.0 cm). Mean consolidation index was 42.9 days/cm. No case of axial deviation requiring surgery and no case of deep infection were recorded. No case of fracture of the regenerate occurred after removal of the external fixator. There were two premature consolidations requiring mobilisation under general anaesthesia, and a case of failure of consolidation requiring surgery. The technique reported provides indisputable biomechanical advantages, particularly increasing stability at the site of osteotomy. The characteristics of implants make this method ideal for lengthenings in children.

Lengthening of the congenital short femur using the Ilizarov technique: a single-surgeon series.

We present a retrospective review of a single-surgeon series of 30 consecutive lengthenings in 27 patients with congenital short femur using the Ilizarov technique performed between 1994 and 2005. The mean increase in length was 5.8 cm/18.65% (3.3 to 10.4, 9.7% to 48.8%), with a mean time in the frame of 223 days (75 to 363). By changing from a distal to a proximal osteotomy for lengthening, the mean range of knee movement was significantly increased from 98.1 degrees to 124.2 degrees (p = 0.041) and there was a trend towards a reduced requirement for quadricepsplasty, although this was not statistically significant (p = 0.07). The overall incidence of regenerate deformation or fracture requiring open reduction and internal fixation was similar in the distal and proximal osteotomy groups (56.7% and 53.8%, respectively). However, in the proximal osteotomy group, pre-placement of a Rush nail reduced this rate from 100% without a nail to 0% with a nail (p < 0.001). When comparing a distal osteotomy with a proximal one over a Rush nail for lengthening, there was a significant decrease in fracture rate from 58.8% to 0% (p = 0.043). We recommend that in this group of patients lengthening of the femur with an Ilizarov construct be carried out through a proximal osteotomy over a Rush nail. Lengthening should also be limited to a maximum of 6 cm during one treatment, or 20% of the original length of the femur, in order to reduce the risk of complications.

Parkes-Weber syndrome associated with a congenital short femur of the affected limb.

The association of capillary malformation, high-flow arteriovenous fistulas, and limb hypertrophy corresponds to Parkes-Weber syndrome. Most of cases are sporadic, although a first familial case has been recently reported. We report the first observation of a Parkes-Weber vascular anomaly with an underlying congenital short femur.