Bilateral Congenital Pseudarthrosis of the Tibia with Neurofibromatosis Type 1: Case Report and Literature Review

Congenital pseudoarthrosis of the tibia (CTP) is a pathology characterized by dysplasia and pathological fractures in the tibia which fail to heal on its own. Its relationship with neurofibromatosis type 1 is already known. A very rare case; an 13 year old child diagnosed with NF1, accompanying bilateral CTP was presented in this article. She also had occasional blood pressure attacks and café au lait spots. She was diagnosed with NF, by gene mutation analysis and the BT results reported that pseudoarthrosis affected both tibiae. The patient was successfully treated by performing fibular grafting and external fixation operation of the tibia with internal and Ilizarov technique. Correction osteotomy was performed and grafted with 20 cc synthetic bone graft on the part of the right tibia where the bowing deformity was observed; the left tibia was not osteotomized as the bowing deformity was slighter. As a result of the 13-month follow-up,

Effect of Slope and Varus Correction High Tibial Osteotomy in the ACL-Deficient and ACL-Reconstructed Knee on Kinematics and ACL Graft Force: A Biomechanical Analysis

Background: Correction of high posterior tibial slope is an important treatment option for revision of anterior cruciate ligament (ACL) failure as seen in clinical and biomechanical studies. In cases with moderate to severe medial compartment arthritis, an additional varus correction osteotomy may be added to improve alignment. Purpose: To investigate the influence of coronal and sagittal correction high tibial osteotomy in ACL-deficient and ACL-reconstructed knees on knee kinematics and ACL graft load. Study Design: Controlled laboratory study. Methods: Ten cadaveric knees were selected according to previous computed tomography measurements with increased native slope and slight varus tibial alignment (mean ± SD): slope, 9.9°± 1.4°; medial proximal tibia angle, 86.5°± 2.1°; age, 47.7 ± 5.8 years. A 10° anterior closing-wedge osteotomy, as well as an additional 5° of simulated varus correction osteotomy, were created and fixed using an external fixator. Four alignment conditions—native, varus correction, slope correction, and combined varus and slope correction—were randomly tested in 2 states: ACL-deficient and ACL-reconstructed. Compressive axial loads were applied to the tibia while mounted on a free-moving X-Y table and free-rotating tibia in a knee testing fixture. Three-dimensional motion tracking captured anterior tibial translation (ATT) and internal tibial rotation. Change of tensile forces on the reconstructed ACL graft were recorded. Results: In the ACL-deficient knee, an isolated varus correction led to a significant increase of ATT by 4.3 ± 4.0 mm ( P = .04). Isolated slope reduction resulted in the greatest decrease of ATT by 6.2 ± 4.3 mm ( P < .001). In the ACL-reconstructed knee, ATT showed comparable changes, while combined varus and slope correction led to lower ATT by 3.7 ± 2.6 mm ( P = .01) than ATT in the native alignment. Internal tibial rotation was not significantly altered by varus correction but significantly increased after isolated slope correction by 4.0°± 4.1° ( P < .01). Each isolated or combined osteotomy showed decreased forces on the graft as compared with the native state. The combined varus and slope osteotomy led to a mean decrease of ACL graft force by 33% at 200 N and by 58% at 400 N as compared with the native condition ( P < .001). Conclusion: A combined varus and slope correction led to a relevant decrease of ATT in the ACL-deficient and ACL-reconstructed cadaveric knee. ACL graft forces were significantly decreased after combined varus and slope correction. Thus, our biomechanical findings support the treatment goal of a perpendicular-aligned tibial plateau for ACL insufficiencies, especially in cases of revision surgery. Clinical Relevance: This study shows the beneficial knee kinematics and reduced forces on the ACL graft after combined varus and slope correction.

Slope-Correction Osteotomy with Lateral Extra-articular Tenodesis and Revision Anterior Cruciate Ligament Reconstruction Is Highly Effective in Treating High-Grade Anterior Knee Laxity

Background: Both an elevated posterior tibial slope (PTS) and high-grade anterior knee laxity are often present in patients who undergo revision anterior cruciate ligament (ACL) surgery, and these conditions are independent risk factors for ACL graft failure. Clinical data on slope-correction osteotomy combined with lateral extra-articular tenodesis (LET) do not yet exist. Purpose: To evaluate the outcomes of patients undergoing revision ACL reconstruction (ACLR) and slope-correction osteotomy combined with LET. Study Design: Case series; Level of evidence, 4. Methods: Between 2016 and 2018, we performed a 2-stage procedure: slope-correction osteotomy was performed first, and then revision ACLR in combination with LET was performed in 22 patients with ACLR failure and high-grade anterior knee laxity. Twenty patients (6 women and 14 men; mean age, 27.8 ± 8.6 years; range, 18-49 years) were evaluated, with a mean follow-up of 30.5 ± 9.3 months (range, 24-56 months), in this retrospective case series. Postoperative failure was defined as a side-to-side difference of ≥5 mm in the Rolimeter test and a pivot-shift grade of 2 or 3. Results: The PTS decreased from 15.3° to 8.9°, the side-to-side difference decreased from 7.2 to 1.1 mm, and the pivot shift was no longer evident in any of the patients. No patients exhibited revision ACLR failure and all patients showed good to excellent postoperative functional scores (mean ± SD: visual analog scale, 0.5 ± 0.6; Tegner, 6.1 ± 0.9; Lysholm, 90.9 ± 6.4; Knee injury and Osteoarthritis Outcome Score [KOOS] Symptoms, 95.2 ± 8.4; KOOS Pain, 94.7 ± 5.2; KOOS Activities of Daily Living, 98.5 ± 3.2; KOOS Function in Sport and Recreation, 86.8 ± 12.4; and KOOS Quality of Life, 65.4 ± 14.9). Conclusion: Slope-correction osteotomy in combination with LET is a safe and reliable procedure in patients with high-grade anterior knee laxity and a PTS of ≥12°. Normal knee joint stability was restored and good to excellent functional scores were achieved after a follow-up of at least 2 years.

Patient-Specific Templates for Corrective Osteotomy

Correction osteotomy using conventional techniques may lead to under and over correction. The advantage of using patient specific templates for osteotomy is to predetermine the exact direction and degree of deformity before surgery and to estimate postoperative limb alignment which must mimic the physiologic loading to secure favorable clinical outcome.

Forty-Year Experience in Application of Correction Osteotomies for Blount Disease Treatment

Long-term results (up to 40 years) of surgical treatment using different types of correction osteotomy in 51 children with Blount disease showed that the operation was necessary but a delayed measure. The authors showed that when deformity achieved the degrees requiring surgical intervention with bone transaction the deforming gonarthrosis inevitably developed at terms up to 10 years after operation. The main causes of varus deformity recurrence were determined, i.e. presence of active but disturbed growth and ossification processes, distal osteotomy level, absence of intraoperative hypercorrection, inobservance of postoperative orthopedic regimen. The only way to achieve good results is early operative intervention directed to growth normalization and formation of proximal tibia with spontaneous deformity correction during the period of child's growth.