What's New in Limb Lengthening and Deformity Correction

Feasibility of Computer-Aided Design in Limb Lengthening Surgery: Surgical Simulation and Guide Plates

Objective

To evaluate the feasibility and utility of computer‐aided design (CAD) in surgical treatment of leg length discrepancy (LLD) using monorail external fixators.

Methods

In the present case series, we retrospectively analyzed seven patients diagnosed with LLD who were surgically treated using a monorail external fixator between June 2018 and August 2020. A personalized surgical emulation of each patient was designed using CAD based on preoperative CT scans to measure limb parameters. Through reverse engineering, a surgical guide plate was then designed to assist with correcting the limb deformity. Patient general information and clinical history, leg length, mechanical lateral distal femoral angle (mLDFA), anatomical anterior distal tibial angle (aADTA), and surgical parameters were recorded during the perioperative period. Three months after external fixator removal, distraction‐consolidation time (DCT), healing index (HI), and lower extremity function score (LEFS) were calculated, and statistically analyzed by paired T‐test.

Results

The mean limb lengthening achieved was 6.41 ± 2.54 (range, 3.30–10.54) cm with either varus or valgus correction. The mean operative duration was 151 ± 41.87 (84–217) minutes and mean blood loss was 53.58 ± 22.51(25–87) ml. The mean distraction‐consolidation time was 3.67 ± 1.13 (range, 2.5–6.0) months and mean external fixator duration was 11 ± 2.45 (range, 8–14) months. The mean healing index (HI) was 18.11 ± 3.58 (range, 12.8–22.7) days/cm. Mean LEFS scores improved postoperatively from 32.17 ± 8.57 (range, 24–45) to 61.17 ± 6.68 (range, 50–67) with a significant difference (T = –14.26,P < 0.001).

Conclusions

Simultaneous length and angular correction can be achieved by incorporating CAD into the surgical treatment of patients with LLD, without compromising postoperative lower limb function. CAD demonstrates utility in the surgical treatment of LLD by improving the functionality of monorail external fixators.

Proximal Femoral Focal Deficiency/Congenital Femoral Deficiency: Evaluation and Management

Proximal focal femoral deficiency is a congenital transverse deficiency in which the femur is globally smaller with a typical proximal deformity at the hip that may include distal involvement of knees, leg, and feet. Congenital femoral deficiency (CFD) describes a broader spectrum of longitudinal deficiency inclusive of proximal focal femoral deficiency. CFD may also include lateral distal femoral hypoplasia, knee cruciate ligament deficiency, rotational instability, patellar dislocation, fibular hemimelia, ray absence, and contralateral limb involvement. Treatment intends to maximize function by limb equalization and deformity correction ranging from nonsurgical management using prosthetics to amputation and may include lengthening, shortening, and complex limb reconstruction. Management decisions depend on overall severity and the patient and family's preferences and priorities. Owing to its complexity, CFD is best treated by clinicians with considerable deformity treatment experience who can help guide decision making and embark on a treatment course that will maximize the functional outcome.

International recognition of the Ilizarov bone reconstruction techniques: Current practice and research (dedicated to 100th birthday of G. A. Ilizarov)

The Ilizarov method is one of the current methods used in bone reconstruction. It originated in the middle of the past century and comprises a number of bone reconstruction techniques executed with a ring external fixator developed by Ilizarov GA. Its main merits are viable new bone formation through distraction osteogenesis, high union rates and functional use of the limb throughout the course of treatment. The study of the phenomenon of distraction osteogenesis induced by tension stress with the Ilizarov apparatus was the impetus for advancement in bone reconstruction surgery. Since then, the original method has been used along with a number of its modifications developed due to emergence of new fixation devices and techniques of their application such as hexapod external fixators and motorized intramedullary lengthening nails. They gave rise to a relatively new orthopedic subspecialty termed “limb lengthening and reconstruction surgery”. Based on a comprehensive literature search, we summarized the recent clinical practice and research in bone reconstruction by the Ilizarov method with a special focus on its modification and recognition by the world orthopedic community. The international influence of the Ilizarov method was reviewed in regard to the origin country of the authors and journal’s rating. The Ilizarov method and other techniques based on distraction osteogenesis have been used in many countries and on all populated continents. It proves its international significance and confirms the greatest contribution of Ilizarov GA to bone reconstruction surgery.