Heterotopic ossification post navigated high tibial osteotomy

Patient-specific cutting guides increase accuracy of medial opening wedge high tibial osteotomy procedure: A retrospective case-control study

Purpose

To compare the accuracy of patient-specific guides (PSCG) to the standard technique in medial open-wedge high tibial osteotomy (OWHTO). Secondary objectives were to evaluate factors that could influence accuracy and to compare the complication rate and operating time for both procedures.

Methods

A retrospective analysis of prospective collected data was performed. Between March 2011 and May 2018, 49 patients with isolated medial knee osteoarthritis who were operated for OWHTO using PSCG and 38 patients using the standard technique were included. Preoperative and postoperative deformities were evaluated on long leg radiographs by measuring the mechanical medial proximal tibial angle, mechanical lateral distal femoral angle, hip knee ankle angle (HKA), and joint line convergence angle. Pre- and postoperative posterior tibial slope was also evaluated. Accuracy was evaluated by analysing the difference between the preoperative planned and the actual postoperative HKA. Operating time and complication rate were also recorded in both groups.

Results

The mean preoperative HKA was 173.4° (±3.1°) in the PSCG group and 173.3° (±2.4°) in the standard group (p = 0.8416). Mean planned HKA were 182.8° (±1.1°) and 184.0° (±0°) respectively for the PSCG and the standard group. Mean postoperative HKA were 181.9° (±1.9°) and 182.6° (±3.1°) respectively for the PSCG and the standard group. An accuracy of ±2° in the HKA was achieved in 44 (90%) in the PSCG group and 24 (65%) in the standard group (p = 0.006). The probability of achieving a HKA accuracy was four times higher for patients in the PSCG group (odds ratio [OR] = 4.06, [1.1; 15.3], p = 0.038). Also, higher preoperative Ahlback grade was associated with precision, all other parameters being equal (OR = 4.2, [0.13; 0.97], p = 0.04).

Conclusion

In this study, the PSCG technique was significantly more accurate for achieving the planned HKA in OWHTO. Complication rates and operating times were comparable between groups.

Level of Evidence

Level IV, case-control study.

The Use of Navigation in Osteotomies Around the Knee

Osteotomies around the knee for treating osteoarthritis or knee instability are currently well-established procedures. Success of these realignment procedures is based on the accuracy and the reliability of correction angles in the coronal and sagittal alignment. In this context of improving precision and adapting the correction to each patient, navigation is currently being widely used. The rationale for its use is based on understanding the advantages and limitations, technical principles, and potential pitfalls. This article describes these areas and the overall clinical outcomes of this system for knee osteotomies.

Computer-Assisted Navigation in High Tibial Osteotomy

Computer-assisted navigation is used to improve the accuracy and precision of correction angles during high tibial osteotomy. Most studies have reported that this technique reduces the outliers of coronal alignment and unintended changes in the tibial posterior slope angle. However, more sophisticated studies are necessary to determine whether the technique will improve the clinical results and long-term survival rates. Knowledge of the navigation technology, surgical techniques and potential pitfalls, the clinical results of previous studies, and understanding of the advantages and limitations of the computer-assisted navigation are crucial to successful application of this new technique in high tibial osteotomy. Herein, we review the evidence concerning this technique from previous studies.

Myositis ossificans after navigated knee surgery: A report of two cases and literature review

Computer-assisted surgery is now a common procedure in the field of orthopedics. We present two patients who developed myositis ossificans, a rare complication after navigated knee surgery. Due to careful follow-up and conservative treatment, surgical excision was avoided in both patients with good clinical results. Development of myositis ossificans after navigated knee surgery should be considered in cases of thigh pain and restricted range of motion of the knee.

Computer assisted alignment of opening wedge high tibial osteotomy provides limited improvement of radiographic outcomes compared to flouroscopic alignment

INTRODUCTION

There are numerous methods available to assist surgeons in the accurate correction of varus alignment during medial opening wedge high tibial osteotomy (MOWHTO). Preoperative planning performed with radiographs or more recently intraoperative computer navigation software has been used. The aim of the study was to compare the accuracy of computer navigated versus non-navigated techniques to correct varus alignment of the knee.

METHOD

The preoperative and postoperative radiographs of 117 knees that underwent MOWHTO were investigated to assess radiographic limb alignment 12-months postoperatively. The desired correction was defined as a weight bearing line (Mikulicz point {MP}) 58% of the width of the tibial plateau from the medial tibial margin. Sixty-five knees were corrected using a conventional technique and 52 knees were corrected using computer navigation.

RESULTS

The mean MP percentage was 59% in the navigated group, compared with 56% in the fluoroscopic group (p=0.183). 51.9% of the navigation knees were corrected to within five percent of the desired correction, in contrast to 38.5% of the fluoroscopically corrected knees (p=0.15). 71.2% of the navigated knees were corrected to within 10% of the desired correction, compared with 63.1% of the fluoroscopically corrected knees (p=0.36). Large preoperative deformities were more accurately corrected with navigation assistance (57% vs 49%, p=0.049).

CONCLUSION

No statistically significant difference was found in the radiographic correction of varus alignment twelve months postoperatively between navigated and fluoroscopic techniques of MOWHTO. However, a subgroup analysis demonstrated that larger preoperative varus deformities may be more accurately corrected using computer navigation.

Applications of computer navigation in sports medicine knee surgery: an evidence-based review

Computer-assisted surgery (CAS) has been investigated in a number of sports medicine procedures in the knee. Current barriers to its widespread introduction include increased costs, duration, and invasiveness of surgery. Randomized trials on the use of CAS in anterior cruciate ligament reconstruction have failed to demonstrate a clinical benefit. Data on CAS use in high tibial osteotomy are more promising; however, long-term studies are lacking. CAS has a number of research applications in knee ligament surgery, and studies continue to explore its use in the treatment of osteochondral lesions. This article reviews the applications of CAS in sports medicine knee surgery and summarizes current literature on clinical outcomes.

Removal of a femoral nail with osseous overgrowth at the end-cap: A navigated and cannulated minimally invasive technique

Intramedullary nail removal can be demanding, especially in cases of implant breakage or bony overgrowth at the end-cap, if the exact insertion depth of the nail is neglected in the index surgery. In the presented case, two challenging nail removals were necessary. The first was performed in a re-nailing procedure due to a pseudarthrosis with implant breakage, and the second was performed during hardware removal after fracture healing in a situation where there was deep intramedullary placement of the exchange nail. For the second implant removal a minimally invasive approach based on instrument placements over a navigated guide-wire was used to reduce the iatrogenic morbidity associated with an extensive open approach to the nail and to decrease the radiation exposure for the patient and the operating team.

Robotic-assisted unicompartmental knee arthroplasty in a patient with combined medial compartment arthritis and subchondral defect of the medial femoral condyle

Subchondral defects, or severe osteoarthritic changes, of the medial compartment may complicate component positioning and require proper planning and exact placement to ensure adequate and stable fixation and proper postoperative kinematics. This is a case report on our experience with a CT-based robotic tactile guidance system for unicompartmental knee replacement in a patient with combined medial compartment degenerative joint disease and subchondral defect of the medial femoral condyle. Using the TGS in this case, an exact burring process of the femoral cavity adjacent to the subchondral defect resulted in accurate burring of the cavity depth and width, while preservation of the surrounding supporting bony boundary was possible.

Computer-assisted navigation in high tibial osteotomy: a systematic review of the literature

High tibial osteotomy (HTO) is a procedure which aims to change the mechanical axis of the lower limb, transferring the body weight across healthy articular cartilage. Several studies have shown that accurate correction is the leading predictor for success.

In this article, we systematically review the computer-assisted techniques that have been used in attempts to increase the accuracy of the surgery and improve postoperative outcomes. The results of the cadaveric and clinical studies to date are presented and the benefits and pitfalls of navigation are discussed.

Fluoro-Free navigated retrograde drilling of osteochondral lesions

PURPOSE

Retrograde drilling of osteochondral lesions (OCLs) is a recommended, but demanding operative approach for revascularization of lesions in stage 1-3 according to Berndt and Harty after failed conservative treatment. The gold standard of intraoperative driller guidance is fluoroscopic control. Limitations are a 2D visualization of a 3D procedure and sometimes limited view of the OCL in fluoroscopy, leading to increased radiation exposure. A new image-free navigation procedure was evaluated for practicability and precision in first clinical applications.

METHODS

In a period of 7 months, retrograde drillings were performed in eight patients (3x femoral condyle, 5x talus) using the new Fluoro-Free navigation procedure without rigidly fixed reference bases.

RESULTS

In total, 29 retrograde drillings were performed without any technical problem. The overall mean operating time was 82.1 ± 29.3 min (34.6 ± 6.4 min for the standard arthroscopy and 11.2 ± 1.2 min per drill). Twenty-seven of 29 drillings hit the target with a 100% first-pass accuracy. Two complications during drilling (one navigation specific and one navigation independent) were observed.

CONCLUSION

The paper describes the promising first clinical applications of a new Fluoro-Free navigation procedure for the retrograde drilling of OCLs determined by arthroscopy. The benefit of that navigated drillings with a high rate of first-pass accuracy and no need for radiation exposure in contrast to standard techniques is highlighted.

Arthroscopic-controlled navigation for retrograde drilling of osteochondral lesions of the talus

BACKGROUND

Retrograde drilling of symptomatic osteochondral lesions (OCL) is usually controlled by fluoroscopy. Due to the limited visualization of the OCLs in the acquired images and the narrow access to the talar dome, this approach can be demanding. Several navigation procedures have been reported (2D- or 3D- fluoroscopy or intraoperative CT-based) to increase the accuracy and reduce the radiation exposure. We developed a new arthroscopic-controlled navigation procedure which is free of radiation exposure and free of a reference base rigidly fixed to the bone. We hypothesized that this procedure (Fluoro-Free) is at least as precise as the standard 2D-Fluoro navigation (2D-Fluoro). Furthermore, our first clinical experiences are described and discussed.

MATERIAL AND METHODS

Sixteen drillings per group (standard 2D-Fluoro vs. Fluoro-Free) were performed in artificial sawbones. Times for the different steps of each drilling procedure were recorded and the precision evaluated by measuring the deviation and depth of drilling.

RESULTS

The accuracy of the Fluoro-Free navigation was as precise as the standard 2D-Fluoro based navigation (axis deviation of drill tip to the target point: 1.07 ± 0.11 versus 1.14 ± 0.15 mm). Due to the simplified workflow without radiation exposure and fixation of a reference base, the Fluoro-Free procedure was significantly faster (mean procedure time per drilling: 23.7 ± 11.6 versus 165 ± 9 seconds) and easy to use. Its clinical usefulness was demonstrated during three retrograde drillings of a talar OCL in a 16-year-old patient.

CONCLUSION

The Fluoro-Free navigation procedure is a simplified approach for retrograde drilling of OCL in the talus under arthroscopic control without radiation exposure and without the need for fixation of a dynamic reference base to the bone.