A novel device for greater precision and safety in open-wedge high tibial osteotomy: cadaveric study

Clinical efficacy and feasibility of laser correction technology with an ordinary laser pen and surgical instrument box in open-wedge high tibial osteotomy

Background

The clinical outcomes of open-wedge high tibial osteotomy (OWHTO) for medial knee osteoarthritis primarily depend on the corrective precision. The present study aimed to determine the efficacy and feasibility of laser correction technology with an ordinary laser pen and surgical instrument box.

Methods

This prospective and randomized trial included 71 patients randomly divided into laser (n = 36) and traditional groups (n = 35). In the laser group, the hip centre, knee (Fujisawa point), and ankle centre were located preoperatively using the surgical instrument box lid. The leg was aligned with an ordinary laser pen. In the traditional group, the lower limb alignment was corrected by a metal cable. Radiation exposure, operative time, and rate of outliers (lower limb force line does not pass through 62–66% of the lateral tibial plateau) were evaluated. The visual analogue scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were recorded. After 24 months, the femoral tibial angle (FTA), medial proximal tibial angle (MPTA), and posterior slope angle (PSA), were recorded. The Kaplan-Meier method was used to evaluate the survival time of affected knees, and postoperative complications were recorded.

Results

The radiation exposure, operative time and rate of outliers were lower in the laser correction group (P < 0.05). Six months postoperatively, the VAS and WOMAC scores were significantly improved in both groups (P < 0.001). At 24 months, the FTA, MPTA, and PSA were corrected in both groups (P < 0.001). There were no differences in the postoperative knee survival time from OWHTO to knee arthroplasty between the groups or postoperative complications (P = 0.53; P = 0.61).

Conclusions

Laser correction technology can effectively reduce radiation exposure, the operative time, and the rate of outliers (trial identification number (retrospectively registered): ChiCTR2200060480; date of register: 03/06/2022).

How accurately can surgeons perform angle manipulation? Quantitative assessment of the accuracy of manual angle manipulation of orthopedic surgery: a cadaver study

INTRODUCTION

To date, only few studies have been performed on the accuracy of manual angle manipulation during orthopedic surgery. This cadaver study was aimed at quantitatively assessing the accuracy of manual angle manipulation performed by orthopedic surgeons according to their surgical experience and comparing it with manipulation performed with the assistance of a digital goniometer.

MATERIALS AND METHODS

Six lower-leg specimens of fresh-frozen human cadavers were subjected to angle manipulation performed via Kirschner wire (K-wire) insertion. K-wires were inserted manually and with the assistance of a digital goniometer at target angles of 0°, 30°, and 60° by three operators who had different levels of experience in orthopedic surgery. The accuracy of the insertion angles at the target angles was evaluated using computed tomography.

RESULTS

The mean angle error in the manual angle manipulation was 8.8° (standard deviation [SD] 6.0). When the target angles were set to 0°, 30°, and 60°, the identified angle errors were 6.1° (SD 4.3), 8.8° (SD 6.6), and 11.7° (SD 5.6), respectively, and each value did not show any significant difference among the operators. With the assistance of a digital goniometer, the mean (SD) angle error was significantly improved to 2.1° (1.1°) (p < 0.001). The amount of improvement in accuracy significantly increased as the target angle increased (p = 0.01).

CONCLUSION

This cadaver study quantified the inaccuracy of manual angle manipulation in orthopedic surgery and showed that these inaccuracies ​​can be improved using an assistive device. These results support the need to develop a device that can compensate manual angle manipulation in orthopedic surgery.

Accuracy of biplanar linear radiography versus conventional radiographs when used for lower limb and implant measurements

INTRODUCTION

The current standard of care for measuring lower extremity length and angular discrepancies is using a full-length standing anteroposterior radiograph. However, there has been increasing interest to use biplanar linear EOS imaging as an alternative. This study aims to compare lower extremity length and implant measurements between biplanar linear and conventional radiographs.

MATERIALS AND METHODS

In this 5-year retrospective study, all patients who had a standing full-length anteroposterior and biplanar linear radiographs (EOS®) that include the lower extremities done within one year of each other were included. Patients who underwent surgery in between the imaging, underwent surgeries that could result in graduated length or angulated corrections and inadequate exposure of the lower extremity were excluded. Four radiographic segments were measured to assess lower limb alignment and length measurements. Height and width measurements of implants were performed for patients who had implants in both imaging.

RESULTS

When comparing imaging and actual implant dimensions, biplanar linear radiographs were accurate in measuring actual implant height (median difference = - 0.14 cm, p = 0.66), and width (median difference = - 0.13 cm, p = 0.71). However, conventional radiographs were inaccurate in measuring actual implant height (median difference = 0.19 cm, p = 0.01) and width (median difference = 0.61 cm, p < 0.01). When comparing conventional and biplanar linear radiographs, there was statistically significant difference in all measurements. This includes anatomical femoral length (median difference = 3.53 cm, p < 0.01), mechanical femoral length (median difference = 3.89 cm, p < 0.01), anatomical tibial length (median difference = 2.34 cm, p < 0.01) and mechanical tibial length (median difference = 2.20 cm, p < 0.01).

CONCLUSION

First, there is a significant difference in the lower extremity length when comparing conventional and biplanar linear radiographs. Second, biplanar linear radiographs are found to be accurate while conventional radiographs are not as accurate in implant measurements of length and width in the lower extremity.

Factors related to the early outcome of medial open wedge high tibial osteotomy: coronal limb alignment affects more than cartilage degeneration state

INTRODUCTION

This study aimed to identify possible factors influencing the early outcome after medial open wedge high tibial osteotomy (MOWHTO).

MATERIALS AND METHODS

A total of 87 MOWHTO cases with a minimum of 2-year follow-up and second-look arthroscopic results available were enrolled. The cartilage degeneration state was evaluated by the International Cartilage Repair Society (ICRS) grading. Radiographic parameters including the hip-knee-ankle axis (HKA), medial proximal tibia angle (MPTA), posterior tibial slope, patellar height, mechanical lateral distal femoral angle (LDFA), joint line convergence angle (JLCA), joint line obliquity (JLO), and weight-bearing line ratio (WBLR) were measured. The pre-operative arthritic change was evaluated by Kellgren-Lawrence (KL) classification. According to the post-operative HKA, knees were divided into three (Under/Optimal/Over-correction) subgroups. Subjective International Knee Documentation Committee (IKDC) scores were evaluated and factors related to post-operative IKDC scores were analyzed.

RESULTS

The pre-operative HKA (P = 0.002), post-operative HKA (P = 0.007), pre-operative MPTA (P = 0.011), and pre-operative WBLR (P = 0.031) were significantly related to the post-operative IKDC score. Cartilage degeneration states evaluated from first and second-look arthroscopy were not associated with post-operative IKDC score. Subgroup analysis revealed that the Under-correction group had significantly lower post-operative IKDC scores compared to the Optimal and Over-correction group (P = 0.012 and P = 0.030, respectively).

CONCLUSION

Our result suggests that a sub-optimal correction of coronal limb alignment negatively affects the early outcome of MOWHTO. On the other hand, the effect of the degree of cartilage degeneration was not significant.

Open-wedge high tibial osteotomy using intraoperative control of joint line convergence angle with reference to preoperative supine radiograph

INTRODUCTION

Preoperative supine joint line convergence angle (JLCA) correlates with postoperative standing JLCA. Here, we compared the radiographic and clinical outcomes of knees with preoperative JLCAs of ≥ 4° and < 4° in open-wedge high tibial osteotomy (OWHTO). We hypothesized that the postoperative coronal alignment in both groups would not be affected by a change in JLCA if this change could predict before surgery.

MATERIALS AND METHODS

Eighty-four patients with medial knee osteoarthritis who underwent OWHTO were enrolled retrospectively. A weight-bearing line (WBL) ratio of 62% and a JCLA equivalent to the preoperative supine JLCA were anticipated in preoperative planning. These were intraoperatively set using an alignment rod and a radiolucent protractor under fluoroscopy. Soft tissue correction was defined as correction angle minus bone correction. The participants with preoperative JLCAs of < 4° (low-JLCA group) and ≥ 4° (high-JLCA group) were compared.

RESULTS

No significant difference in the coronal alignment was found between the groups after OWHTO. No significant differences in correction angle or bone correction were found between the groups, but the soft tissue correction in the high-JLCA group was higher than that in the low-JLCA group after OWHTO (p = 0.013).

CONCLUSIONS

When we controlled intraoperative JLCA, the postoperative coronal alignment was not affected by the change in JLCA and the differences in soft tissue correction between the low-JLCA and high-JLCA groups. However, overcorrection compared with the target coronal alignment remained in both groups.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Intraoperatively accurate limb alignment after opening wedge high tibial osteotomy can be lost by large knee joint line convergence angle during surgery

INTRODUCTION

The purpose of this study was to assess early postoperative loss of achieved correction and associated factors after opening wedge high tibial osteotomy (OWHTO).

MATERIALS AND METHODS

OWHTO was performed in 121 patients with osteoarthritis of the knee (mean age 66 years, 154 knees). Anteroposterior radiographs of the knee and full-length leg, and varus and valgus stress radiographs of the knee were taken, and the femorotibial angle (FTA), joint line convergence angle (JLCA), and medial proximal tibial angle (MPTA) were measured. The changes in the FTA, JLCA, and MPTA were defined as ΔFTA, ΔJLCA, and ΔMPTA.

RESULTS

The ΔFTA and ΔJLCA at postoperative 0-2 days were - 1.8 ± 1.2° and - 1.9 ± 1.4°, respectively. The ΔFTA, ΔJLCA and ΔMPTA at postoperative 1-12 months were 0.9 ± 1.3°, 0.2 ± 1.2° and - 0.8 ± 0.8°, respectively. A positive correlation was found between ΔFTA and ΔJLCA at postoperative 0-2 days (ρ = 0.642, P < 0.001) and at postoperative 1-12 months (ρ = 0.402, P < 0.001). A negative correlation was found between ΔFTA and ΔMPTA at postoperative 1-12 months (ρ = - 0.534, P < 0.001). A discrepancy in alignment represented by the FTA occurred in the supine radiographs between the day of surgery and postoperative 2 days. Multiple regression analysis suggested that postoperative JLCA on the day of surgery was the factor related to early postoperative change of the FTA.

CONCLUSIONS

This study demonstrated the early loss of achieved correction after OWHTO due to change of the JLCA, even if the accurate alignment is obtained intraoperatively.