Deformity progression in congenital posteromedial bowing of the tibia: a report of 44 cases

Overlooked valgus bowing deformity in pediatric tibial shaft fractures with/without fibular involvement: Cause residual valgus alignment in 2-year follow-up

BACKGROUND

Children with a tibial shaft fracture often present with valgus malalignment, even when anatomical reduction had been achieved at the fracture site. Pediatric bony structure has more elastic bones than that of adults, it can cause bowing deformity. Therefore, we evaluated pediatric tibial shaft fracture for the presence of bowing deformity, associated risk factors, and its clinical significance.

HYPOTHESIS

There is an overlooked bowing deformity in pediatric tibial shaft fracture.

PATIENTS AND METHODS

Fifty-seven tibial shaft fracture patients aged 2 to 15 years with Risser stage 0 were retrospectively reviewed. Clinicoradiologic factors and radiographs taken within 3 post-traumatic months and at 2 years were assessed. To evaluate the tibial bowing deformity, the tibial interphyseal angle and tibial shaft angle were measured, and their differences were calculated as a tibial bowing angle.

RESULTS

Multivariate analysis revealed the tibial shaft fracture with fibular involvement is significantly associated with a higher initial tibial bowing angle (valgus deformity). The tibial bowing angle did not change over 2-year follow-up. A high initial tibial bowing angle (≥ 5°) was a significant risk factor for the persistence of valgus malalignment.

DISCUSSION

Pediatric tibial shaft fractures with/without fibular involvement carry the risk of valgus bowing deformity, which may not develop during post-traumatic growth but may be present at the time of injury. The risk is high if the tibial fracture is accompanied by a fibular fracture. This tibial deformity presents limited remodeling potential at 2-year follow-up.

LEVEL OF EVIDENCE

IV; retrospective study.

Lengthening in congenital posteromedial bowing of tibia: a follow-up series at skeletal maturity

PURPOSE

Congenital posteromedial bowing (CPMB) of tibia is a rare, usually self-resolving condition that is present at birth. The data on the long-term outcome of lengthening, choice of fixator, outcome in early and late age groups, and complications is sparse, hence the need for this study.

METHODS

This retrospective study included 93 patients with 94 affected legs from 1991 to 2023. The patients were categorized into early (under 10 years) and late (10 years or above) intervention groups. Eighteen patients with nineteen lengthening episodes who attained skeletal maturity made the basis of this study and will be discussed in detail.

RESULTS

The outcome for the lengthening group at maturity was satisfactory, with 5.53 cm of average length gained per lengthening episode, a mean LLD of 0.31 cm at final follow-up, a mean age of 23.63 years (range 14-38 years), and an average follow-up of 12.51 years (range 3-28 years) post-lengthening, but the procedure was associated with difficulties like ankle stiffness, tibial valgus, pin tract infections, and fractures through regenerate.

CONCLUSION

This study represents a large single-centre series on CPMB. We recommend that surgery for lengthening should be done at an older age, close to skeletal maturity, wherever possible to reduce the risk of repeat lengthening procedures. Based on our experience, we recommend the use of a circular fixator. Uniplanar distractors should have an adequate number and spread of Schanz screws in each segment to reduce the risk of valgus malalignment of distracting segments of bone.

Ipsilateral Healthy-segment Response to Leg Length Discrepancy

BACKGROUND

Few studies address frequency or magnitude of healthy lower-extremity segment response to ipsilateral companion segment shortening. We sought to document and quantify this occurrence in a variety of pediatric etiologies.

METHODS

We reviewed the medical record and radiographs of patients undergoing epiphysiodesis to manage leg length discrepancy. Inclusion criteria for this study were leg length discrepancy of a single lower-extremity segment by identifiable cause and adequate scanograms to allow accurate measurement of all 4 lower-extremity segments before any surgical treatment for the discrepancy. We recorded the etiology of shortening, age of onset of disorder, the length of the lower-extremity segments on scanograms, and age at the time of radiographs. We considered ipsilateral healthy-segment difference from the contralateral ≥ 0.5 cm. as clinically significant.

RESULTS

Two hundred nine patients met inclusion criteria (126 boys, 83 girls). The average age was 12.5 years. 16/60 patients with avascular necrosis of the hip demonstrated ipsilateral tibial shortening averaging 1.2 cm whereas 6/60 demonstrated ipsilateral tibial overgrowth averaging 0.6 cm. 11/30 Legg-Perthés patients demonstrated ipsilateral tibial shortening averaging 0.7 cm; none had ipsilateral tibial overgrowth. 10/42 posteromedial bow patients had ipsilateral femoral shortening averaging 0.8 cm, whereas 6/42 had ipsilateral overgrowth averaging 0.8 cm. 13/48 with distal femoral physeal injury demonstrated ipsilateral tibial shortening averaging 1.2 cm, whereas 6/48 demonstrated ipsilateral tibial overgrowth averaging 0.8 cm. 8/29 tibial physeal injuries (proximal or distal) demonstrated ipsilateral femoral shortening averaging 1.1 cm. whereas 7/29 demonstrated ipsilateral femoral overgrowth averaging 0.7 cm.

CONCLUSIONS

Although there are individual exceptions, the ipsilateral healthy segment does not grow appreciably more than the contralateral in patients with avascular necrosis of the hip, Legg-Perthés disease, or physeal trauma. The femur is not a significant component of shortening in patients with posteromedial bow.

LEVEL OF EVIDENCE

Level III, retrospective review.

Is the High Healing Index a Complication of Progressive Long Bone Lengthening? Observations from a Cohort of 178 Children Treated with Circular External Fixation for Lower Limb Length Discrepancy

The use of external fixators (EFs) for lower limb lengthening is common for treating lower limb length discrepancy (LLD) in children. The concern at present revolves around extended treatment times, with some suggesting a healing index (HI) > 45 days/cm as a major complication. The aim of this study is to assess the factors affecting bone healing and treatment duration in children who undergo limb lengthening for LLD using circular EFs. A total of 240 lengthening procedures on 178 children affected by congenital or acquired LLDs (mean age at surgery 13.8 ± 2.8 years) were retrospectively evaluated. Complications according to Lascombes' classification and treatment duration factors were analyzed. Mean HI was 57 ± 25 days/cm for the femur and 55 ± 24 days/cm for the tibia, with an HI > 45 days/cm in 64% of the procedures. A total of 189 procedures (79%) reported complications; 85 had an HI > 45 days/cm as the sole complication. While reducing the frame time is crucial, revising the classifications is necessary to avoid the overestimation of complications.

Congenital Posteromedial Bowing of Tibia: Comparison of Early and Late Lengthening

BACKGROUND

Congenital posteromedial bowing of tibia (CPMBT), a rare anomaly, is characterized by a decreasing deformity and a gradually increasing limb shortening. Lengthening in CPMBT has not been studied extensively. Our series compares the duration and complications of lengthening in younger versus older children to determine early lengthening safety and benefits.

METHODS

We studied 28 tibial lengthenings performed by a single surgeon in 23 patients, divided into 2 equal groups of 14 segments: group A 5 years or younger (preschool) and group B above 5 years. All were lengthened with circular external fixators, of which 3 were lengthened over a nail. We measured preoperative (bo) and postoperative (po) sagittal, coronal, and oblique plane deformities, initial limb length discrepancy (LLD), percentage LLD (% LLD), amount of lengthening (AmtL), percentage lengthening (%L), external fixator duration (EFD), and external fixator index (EFI). We graded complications by Lascombes' criteria, results by Association for the Study and Application of the Methods of Ilizarov bone score.

RESULTS

The mean age was 8.8±7.1 years; the mean follow-up was 7.9 years. Group A had significantly greater bo-sagittal, coronal, and oblique plane deformities. Mean LLD (3.4 cm in group A vs. 4.1 cm in group B) was similar in both. Expected LLD at maturity (LLDM) using the multiplier method was greater than previously reported (mean, range in group A: 7.2 cm, 4.4 to 9.5 cm; group B: 5 cm, 2.5 to 9.7 cm). Though AmtL (3.5 and 4.1 cm) was similar in both, %L was 24% in group A and 15.7% in group B (P=0.002). EFD (116.6 days) and EFI (33.7 days/cm) were lesser in group A compared with group B (200.3 days, P=0.001; 50.2 days/cm, P=0.01). Lascombes' triple contract was fulfilled in 11/14 lengthenings in group A versus 3/14 in group B. Association for the Study and Application of the Methods of Ilizarov bone score was good and excellent in both groups (P=0.44).

CONCLUSIONS

In a large series of lengthenings in CPMBT, we found younger children presenting with large deformities and large projected length discrepancies could be safely lengthened with significantly lesser EFD and complications than in older children.

LEVEL OF EVIDENCE

Level IV-therapeutic study.