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

Influence of different standing positions on anatomical parameters of coronal whole-leg weight-bearing radiographs in preoperative planning for high tibial osteotomy

Purpose

The purpose of this study was to assess the differences in lower limb global alignment and anatomical parameters of coronal whole-leg radiographs, which were generally used in preoperative planning for high tibial osteotomy (HTO), according to different weight-bearing standing positions.

Methods

Between April 2021 and December 2022, 176 patients (60 males and 116 females) were investigated. Full-weight-bearing coronal whole-leg radiographs were obtained with the patella centred on the femoral condyle. Patients were divided by Kellgren-Lawrence grade (KL-0, KL-I, KL-II and KL-III) and assessed in two standing positions: legs closed and legs spread. Patients with flexion contractures or those unable to stand with full weight bearing were excluded. The mechanical distal femoral angle, medial proximal tibial angle (MPTA), femorotibial angle, joint line convergence angle, percentage weight-bearing line (%WBL) and hip-knee-ankle angle (HKAA) were measured. The Student's t test was used to compare the two standing positions. A p value < 0.05 indicated a statistically significant difference.

Results

The MPTAs of legs closed standing and legs spread standing were 84.9 ± 2.6° and 85.1 ± 2.4° in KL-0, 84.7 ± 2.0° and 84.9 ± 2.1° in KL-I and 85.0 ± 2.43° and 85.4 ± 2.4° in KL-II, respectively. There were statistically significant differences in the MPTA between the two standing positions in KL-0, KL-I and KL-II. In contrast, the %WBL and HKAA did not change regardless of the standing position. In the KL-III group, no statistical significance was observed for any of the anatomical parameters.

Conclusion

Several anatomical parameters were changed between the legs closed standing and the legs spread standing positions. It was suggested that the standing position should be taken into consideration in the planning for HTO.

Level of Evidence

Level IV, Case series with no comparison group.

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.

Corrective Osteotomies in Severe Non-Idiopathic Lower Limb Alignment Disorders in the Aspect of Future Joint Endoprosthesis-A Perspective Study

The aim of this study was to retrospectively evaluate the effectiveness of corrective osteotomies in lower limb axis disorders at different levels of non-idiopathic (post traumatic, developmental, post-septic) etiology. A total of 50 patients were divided into three groups: A-thigh segment alignment disorder (24 patients); B-tibia segment alignment disorder (18 patients); C-thigh and tibia segment alignment disorder (8 patients). Radiological evaluation of digital lower limb postural X-ray was performed laterally and for AP, and included mLPFA, mLDFA, MAD, CORA coronal and sagittal plane parameters for the femur segment and mMPTA, mLDTA, MAD, CORA coronal and sagittal plane for the tibia segment. Clinical assessment was based on the LLFI. The mean follow-up was 55.8 months (12-86). Improvements in the radiological parameters and statistical significance were achieved for all measurements in all groups (p < 0.05). The most common plane of deformation was the coronal plane (varus/valgus), followed by the transverse (rotational) and sagittal planes (procurvatum/recurvatum). In this study, we examined 29 post-traumatic deformities and 21 other etiologies. Improvements in the LLFI score performance after corrective osteotomies were observed in all three groups. Corrective osteotomies are a safe and useful but challenging method of preserving joints in cases of post-traumatic, developmental or post-septic lower limb alignment disorders.

Changes in sagittal and axial plane alignment in medial opening wedge high tibial osteotomy: a prospective observational study

PURPOSE

Deformity correction during high tibial osteotomy is generally based on coronal plane alignment. The aim of this study was to measure changes in sagittal and axial plane alignment following medial opening wedge high tibial osteotomy [mHTO], using pre- and postoperative computed tomography [CT] scans, and correlate them with changes in coronal plane. The secondary objective was to correlate changes in functional outcomes with changes in alignment in each plane. The null hypothesis was that sagittal and axial plane alignment does not change significantly following mHTO.

METHODS

This was a prospective, observational study including 30 patients of isolated medial compartment osteoarthritis of the knee joint, between 30 and 60 years of age. Preoperative and postoperative computed tomography scan of bilateral lower limbs from hip to ankle was performed. Varus angle, mechanical axis deviation [MAD] of the lower limb, medial proximal tibial angle [MPTA], tibial torsion and posterior proximal tibial angle [PPTA] were measured. Visual Analogue Scale [VAS 0-10 cm scale] was used for assessment of pain. Functional outcomes were evaluated using Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], 12 Item Short Form Survey [SF 12] and Tegner Lysholm knee scoring scale.

RESULTS

Mean age of patients was 44.59 ± 8.157 years. Mean preoperative varus deformity was 11.13 ± 1.5 degrees, which got corrected to a mean valgus alignment of 3.8 ± 0.93 degrees postoperatively. The mechanical axis deviation was 4.32 ± 1.76 mm lateral to the knee joint center postoperatively. Preoperatively, all knees had external tibial torsion [27.08 ± 2.18 degrees] which was corrected to a mean external tibial torsion of 19.80 ± 3.72 degree after the surgery [P < 0.001]. The overall decrease in sagittal alignment in the present study was 3.70 ± 3.14 degree, 3.97 ± 3.06 degree, 3.92 ± 2.33 degree, for medial, middle and lateral cuts, respectively. There was a significant correlation between change in varus/valgus angle and change in TT and PPTA. Significant positive correlation was seen between change in coronal alignment and functional outcome scores.

CONCLUSION

This study has shown that mHTO significantly changes torsional and sagittal alignment. This is the first study to establish relation between correction in coronal plane and associated changes in sagittal and torsional alignments.

Intraoperative alignment correlates well with long standing radiographs - The X-ray grid method in complex knee surgery

OBJECTIVE

While long standing radiographs (LSR) represent the gold standard for preoperative alignment assessment and planning of lower limb deformity corrections, there is no consensus about the intraoperative alignment assesments (IAC) due to various limitations of the common methods. The present study introduces a radiolucent X-ray grid with integrated radiopaque lines explicitly designed for fluoroscopic IAC and evaluates its reliability in comparsion to the LSR.

METHODS

Patients with posttaumatic and congenital lower limb deformity surgery and preoperative LSR as well as fluoroscopic IAC utilizing the X-ray grid were retrospectively included to the study. The mechanical axis deviation (MAD) in percentage of the maximum tibial width from the medial to the lateral in comparison between the image pairs was set as primary outcome parameter. Multiple rater and measurements determined intra- and interobserver reliabilit of both imaging methods. In addition, the effects of age, gender, body mass index (BMI), etiology, joint line convergence angle (JLCA), and extent varus or valgus deformity were analysed.

RESULTS

A total of 84 patients were finally included. The mean absolute difference of MAD between the two techniques was 7.2 ± 0.8%. MAD between the LSR and IAC correlated at a high level (R = 0.96, p <0.001). The agreement decreased with increasing extent of deformity (p <0.01) and with higher deviation of JLCA between LSR and IAC (p <0.01). Intra- and interobserver concordance correlation coefficient (CCC) for MAD measurements were 0.99 for both imaging techniques.

CONCLUSION

Fluoroscopy combined with the X-ray grid method is a valid tool for intraoperative assessment of lower limb alignment in deformity correction surgery, and the correlation between LSR and IAC is better than in other similar techniques described in the literature. However, in case of severe coronal alignment deformity and highly divergent JLCA, the agreement between both imaging techniques decreases significantly.

Extreme Hinge Axis Positions Are Necessary to Achieve Posterior Tibial Slope Reduction With Small Coronal-Plane Corrections in Medial Opening Wedge High Tibial Osteotomy

Background:

Both coronal- and sagittal-plane knee malalignment can increase the risk of ligamentous injuries and the progression of degenerative joint disease. High tibial osteotomy can achieve multiplanar correction, but determining the precise hinge axis position for osteotomy is technically challenging.

Purpose:

To create computed tomography (CT)–based patient-specific models to identify the ideal hinge axis position angle and the amount of maximum opening in medial opening wedge high tibial osteotomy (MOWHTO) required to achieve the desired multiplanar correction.

Study Design:

Descriptive laboratory study.

Methods:

A total of 10 patients with lower extremity CT scans were included. Baseline measurements including the mechanical tibiofemoral angle (mTFA) and the posterior tibial slope (PTS) were calculated. Virtual osteotomy was performed to achieve (1) a specified degree of PTS correction and (2) a planned degree of mTFA correction. The mean hinge axis position angle for MOWHTO to maintain an anatomic PTS (no slope correction) was 102.6° ± 8.3° relative to the posterior condylar axis (PCA). Using this as the baseline correction, the resultant hinge axis position and maximum opening were then calculated for each subsequent osteotomy procedure.

Results:

For 5.0° of mTFA correction, the hinge axis position was decreased by 6.8°, and the maximum opening was increased by 0.49 mm for every 1° of PTS correction. For 10.0° of mTFA correction, the hinge axis position was decreased by 5.2°, and the maximum opening was increased by 0.37 mm for every 1° of PTS correction. There was a significant difference in the trend-line slopes for hinge axis position versus PTS correction (P = .013) and a significant difference in the trend-line intercepts for maximum opening versus PTS correction (P < .0001).

Conclusion:

The mean hinge axis position for slope-neutral osteotomy was 102.6° ± 8.3° relative to the PCA. For smaller corrections in the coronal plane, more extreme hinge axis positions were necessary to achieve higher magnitudes of PTS reduction.

Clinical Relevance:

Extreme hinge axis positions are technically challenging and can lead to unstable osteotomy. Patient-specific instrumentation may allow for precise correction to be more readily achieved.

Poor Accuracy of Intraoperation Medial Proximal Tibial Angle Measurement Compared to Alignment Rod Methods in Open-Wedge High Tibial Osteotomy for Medial Knee Osteoarthritis

The alignment rod is widely used as an index for intraoperative alignment but alignment error is inevitable. The purpose of this study was to verify the accuracy of lower limb alignment correction by measurement of mechanical medial proximal tibial angle (MPTA) as an index in open-wedge high tibial osteotomy (OWHTO). This study was retrospective case series. This study involved 152 patients undergoing OWHTO for primary medial osteoarthritis. Alignment rod or MPTA measurement board was used as an index of optimal correction in OWHTO. Alignment rod was used from October 2013 to May 2017, and MPTA measurement board was used from June 2017 to April 2020. The correction using an alignment rod was that the weight-bearing line ratio (WBLR) passed through 62.5% of the tibial plateau which was defined as Fujisawa's point under intraoperative fluoroscopy (A rod group). The correction using MPTA measurement board was aligning the intraoperative MPTA to the preplanned angle (MPTA group). Preplanned optimal alignment was defined as Fujisawa's point in all patients. Knee injury and osteoarthritis outcome measure (KOOS), Knee Society scoring system objective knee score (KSS), 3-m timed up-and-go test (TUG), single-limb standing test (SLS), and isometric muscle strength of quadriceps and hamstrings were assessed as clinical results. WBLR, MPTA, joint-line convergence angle (JLCA), and joint-line obliquity (JLO) were assessed as radiological results preoperatively and at 1 year after surgery. The clinical and radiological results after OWHTO were compared with both groups. Postoperative WBLR in A rod group was closer to the target alignment (Fujisawa's point: 62.5) than in the MPTA group at all stage (A rod group vs. MPTA group: 63.1 vs. 54.6 at 6 months; 62.0 vs. 53.4 at 1 year; p < 0.001). There were no significant differences in the clinical results between both groups. The intraoperative measurement of medial proximal tibial angle has a risk of undercorrection after OWHTO. His study is a retrospective case series and reflects level of evidence IV.

Osteotomy Around the Knee: The Surgical Treatment of Osteoarthritis

Osteoarthritis causes joint pain and functional disorder, of which knee osteoarthritis is the most common. Nowadays, clinically effective treatments mainly include conservative treatment, arthroplasty, and osteotomy. However, conservative treatment only offers symptomatic relief and arthroplasty is limited to the patients with a moderate to severe degree of osteoarthritis. For relatively young patients who require greater knee preservation, a surgical treatment with low operation trauma and revision rate is needed. Osteotomy around the knee, based on the notion of “knee preservation,” has been chosen as an alternative surgical treatment. Cutting and realigning the bones corrects the mechanical line of lower limb force bearing. As such, osteotomy around the knee retains normal anatomical structure and obtains good functional recovery of the knee joint. The techniques of osteotomy around the knee includes anti‐varus deformity and anti‐valgus deformity osteotomy, aiming to reallocate the force bearing in the compartment of the knee joint. By choosing the surgical section of the lower limbs, the osteotomy around the knee can achieve the correction of mechanical axis, such as the high tibial osteotomy (HTO), proximal fibular osteotomy (PFO), and distal femur osteotomy (DFO). Numerous modified techniques have been developed to meet the demands of patients based on traditional methods. These modified osteotomy have their own advantages and indications. This paper aims to guide clinical treatment by reviewing different types of osteotomies, and their effects, that have been studied and applied widely in clinical practices.

Complications, Additional Surgery, and Joint Survival Analysis After Medial Open-Wedge High Tibial Osteotomy

The reported incidence of complications following medial open-wedge high tibial osteotomy (MOWHTO) varies. The authors sought to assess the complications, additional surgeries, and joint survival following MOWHTO in patients with isolated medial compartment arthrosis during a mean follow-up of 10 years. This retrospective study involved patients implanted with spacer plates, angle adjustable plates, or inverse L-type plates with wedges between 2000 and 2010. A total of 504 knees from 441 patients were examined. Mean age of the study population was 52.6±7.0 years, with 56 (11.1%) knees from men and 448 (88.9%) from women. The 10-year Kaplan-Meier joint survival rate was 94.8%. Overall complication rate for MOWHTO was 63.7%, with complications in 20.3% of treated knees requiring additional surgery. In this population, although the overall complication rate and the need for additional surgery were high, the need for additional surgery resulting from serious complications was low (2.6%). The high joint survival rate and low rate of additional surgery for serious complications indicate that MOWHTO can be safely applied in patients with isolated medial gonarthrosis. [Orthopedics. 2020;43(5):303-314.].

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.

Clinical Experience Using a 3D-Printed Patient-Specific Instrument for Medial Opening Wedge High Tibial Osteotomy

Purpose

High tibial osteotomy (HTO) has been adopted as an effective surgery for medial degeneration of the osteoarthritis (OA) knee. However, satisfactory outcomes necessitate the precise creation and distraction of osteotomized wedges and the use of intraoperative X-ray images to continually monitor the wedge-related manipulation. Thus HTO is highly technique-demanding and has a high radiation exposure. We report a patient-specific instrument (PSI) guide for the precise creation and distraction of HTO wedge.

Methods

This study first parameterized five HTO procedures to serve as a design rationale for an innovative PSI guide. Preoperative X-ray and computed tomography- (CT-) scanning images were used to design and fabricate PSI guides for clinical use. The weight-bearing line (WBL) of the ten patients was shifted to the Fujisawa's point and instrumented using the TomoFix system. The radiological results of the PSI-guided HTO surgery were evaluated by the WBL percentage and tibial slope.

Results

All patients consistently showed an increased range of motion and a decrease in pain and discomfort at about three-month follow-up. This study demonstrates the satisfactory accuracy of the WBL adjustment and tibial slope maintenance after HTO with PSI guide. For all patients, the average pre- and postoperative WBL are, respectively, 14.2% and 60.2%, while the tibial slopes are 9.9 and 10.1 degrees. The standard deviations are 2.78 and 0.36, respectively, in postoperative WBL and tibial slope. The relative errors of the pre- and postoperative WBL percentage and tibial slope averaged 4.9% and 4.1%, respectively.

Conclusion

Instead of using navigator systems, this study integrated 2D and 3D preoperative planning to create a PSI guide that could most likely render the outcomes close to the planning. The PSI guide is a precise procedure that is time-saving, radiation-reducing, and relatively easy to use. Precise osteotomy and good short-term results were achieved with the PSI guide.

Comparison of navigated and conventional high tibial osteotomy for the treatment of osteoarthritic knees with varus deformity: A meta-analysis

BACKGROUND

High tibial osteotomy (HTO) is a usefully surgical procedure to correct the malalignment and delay the progression of osteoarthritis. It is still controversy whether navigation system can offer more accuracy of targeted alignment and achieve better clinical outcomes than conventional method. The purpose of present meta-analysis was to investigate whether navigation system was superior to conventional method with regard to clinical and radiographic outcomes.

METHOD

The included studies compared the clinical and radiographic outcomes between navigated HTO group and conventional group. The clinical assessments were Lysholm Score, AKS Function Score and Arc of motion, and the radiographic outcomes were Mechanical axis (MA), Weight bearing line ratio (WBL), Outliers of alignment and Change in TPS used to evaluate alignment correction. The meta-analysis was performed using Review Manager 5.3 software. Downs and Black and the Newcastle-Ottawa Scale (NOS) were used to evaluate the study quality.

RESULT

Sixteen studies were eligible in present meta-analysis, including thirteen studies concerning opening wedge HTO and three studies involving closing wedge HTO. Clinical outcomes were only reported in studies which used opening wedge HTO. No significant differences were observed in all clinical outcomes between navigated and conventional HTO. Regarding radiographic outcomes, no significant difference in WBL ratio was observed between navigated and conventional HTO. Patients undergoing navigated HTO were associated with significantly greater in MA and lower in Outliers of alignment compared with those undergoing conventional HTO. Compared with conventional HTO, increase in TPS was significantly lower in navigated HTO group using opening wedge HTO, but decrease in TPS was significantly greater in navigated HTO group using closing wedge HTO.

CONCLUSION

Our meta-analysis demonstrated that navigated HTO offered more accuracy and precision of alignment correction, except WBL ratio. However, better clinical outcomes were not observed in navigation group.

Open-wedge high tibial osteotomy: incidence of lateral cortex fractures and influence of fixation device on osteotomy healing

PURPOSE

Open-wedge high tibial osteotomy (HTO) is an established treatment for young and middle-aged patients with medial compartment knee osteoarthritis and varus malalignment. Although not intended, a lateral cortex fracture might occur during this procedure. Different fixation devices are available to repair such fractures. This study was performed to evaluate osteotomy healing after fixation with two different locking plates.

METHODS

Sixty-nine medial open-wedge HTO without bone grafting were followed until osteotomy healing.

RESULTS

In patients with an intact lateral hinge, no problems were noted with either locking plate. A fracture of the lateral cortex occurred in 21 patients (30.4 %). In ten patients, the fracture was not recognized during surgery but was visible on the radiographs at the 6-week follow-up. Lateral cortex fracture resulted in non-union with the need for surgical treatment in three out of eight (37.5 %) patients using the newly introduced locking plate (Position HTO Maxi Plate), while this did not occur with a well-established locking plate (TomoFix) (0 out of 13, p = 0.023).

CONCLUSION

With regard to other adverse events, no differences between both implants were observed. In cases of lateral cortex fracture, fixation with a smaller locking plate resulted in a relevant number of non-unions. Therefore, it is recommended that bone grafting, another fixation system, or an additional lateral fixation should be used in cases with lateral cortex fracture.

LEVEL OF EVIDENCE

III.

Comparing the accuracy of high tibial osteotomies between computer navigation and conventional methods

BACKGROUND

The accuracy of correction has been shown to be an important determinant in long-term outcomes of patients who were treated with a medial open-wedge high tibial osteotomy (HTO) who suffer from unicompartmental osteoarthritis (OA). Computer navigation systems have the potential to improve surgical precision. The purpose of this study was to compare radiographic outcomes between patients treated with a navigation system and those treated through conventional methods of assessing alignment intra-operatively. The null hypothesis was that the method of assessing the alignment intra-operatively would make no difference in the accuracy of correction.

METHODS

In this retrospective study, 107 patients with medial varus OA who were managed by open-wedge HTO were included. Of the 107 patients, 41 were treated using an intraoperative navigation system and 66 were treated using conventional methods. Pre-operative and post-operative single-leg, long-leg standing alignment films were used to determine the extent of pre-operative varus deformity and the post-surgical correction achieved compared to the predetermined target range.

RESULTS

The navigational system had eight instances of software malfunction (19.5%) intra-operatively and correction was determined using the cable method. These results were analyzed as part of the conventional group. Post-operative radiographic differences were significant between the two groups. In the navigation group, 75.8% of the patients were corrected within the target range compared to 66.2% in the conventional group. More patients were also under corrected (to the point of remaining in varus) using conventional methods compared to a navigation system. There was no statistically significant difference in the degree of correction in the sagittal plane between the two groups. Regardless of the method used for checking alignment intra-operatively, there was a statistically significant difference in post-operative weight-bearing measurements when the surgeon had intra-operative axial loading versus when they did not.

CONCLUSION

For coronal plane corrections, the navigation system was shown to have greater success in achieving the desired correction value and in having fewer patients who were under corrected. Despite the measurement technique a surgeon chooses to assess the accuracy of correction, axial loading the extremity in order to simulate the weight-bearing film alignment post-operatively is important to maximize the accuracy of correction needed.

How accurately does high tibial osteotomy correct the mechanical axis of an arthritic varus knee? A systematic review

BACKGROUND

The aim of this study was to give an overview of the accuracy of coronal limb alignment correction after high tibial osteotomy (HTO) for the arthritic varus knee by performing a systematic review of the literature.

METHODS

The databases PubMed, MEDLINE and Cochrane Library were screened for relevant articles. Only prospective clinical studies with the accuracy of alignment correction by performing HTO as primary or secondary objective were included.

RESULTS

Fifteen studies were included in this systematic review and were subdivided in 23 cohorts. A total of 966 procedures were considered. Nine cohorts used computer navigation during HTO and the other 14 cohorts used a conventional method. In seven computer navigation cohorts, at least 75% of the study population fell into the accepted "range of accuracy" (AR) as proposed by the different studies, but only six out of 14 conventional cohorts reached this percentage. Four out of eight conventional cohorts that provided data on under- and overcorrection, had a tendency to undercorrection.

CONCLUSIONS

The accuracy of coronal alignment corrections using conventional HTO falls short. The number of procedures outside the proposed AR is surprising and exposes a critical concern for modern HTO. Computer navigation might improve the accuracy of correction, but its use is not widespread among orthopedic surgeons. Although HTO procedures have been shown to be successful in the treatment of unicompartmental knee arthritis when performed accurately, the results of this review stress the importance of ongoing efforts in order to improve correction accuracy in modern HTO.

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.

A Novel System for Navigation-and Robot-Assisted Craniofacial Surgery: Establishment of the Principle Prototype

PURPOSE

The authors aimed to develop 1 novel navigation-guided robotic system for craniofacial surgery to improve accuracy during operation.

MATERIALS AND METHODS

A new 7-DOF (7-degree-of-freedom) robotic arm was designed and manufactured. Based on our self-developed navigation system TBNAVIS-CMFS, the key technique of integration was studied. A phantom skull model was manufactured based on computed tomography image data and used for the preexperimental study. Firstly, virtual planning was achieved through the TBNAVIS-CMFS, where the Le Fort I procedure was executed through simulation. Then, the actual Le Fort 1 osteotomy was expected to perform with the use of the robotic arm following the instructions from the navigation system.

RESULTS

The theoretical prototype of navigation-guided robotic system for craniofacial surgery was established successfully, which performed the planned Le Fort I procedure with the whole process visible on the screen.

CONCLUSIONS

The technical method of navigation-guided robotics system, allowing the operator to practice the virtual planning procedure through navigation system as well as perform the actual operation thru the robotic arm, could be regarded as a valuable option for benefiting craniofacial surgeons.

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.

Opening wedge high tibial osteotomy: navigation system compared to the conventional technique in a controlled clinical study

PURPOSE

This study aimed to verify if the navigation system used in high tibial osteotomy (HTO) adds precision to the procedure regarding mechanical axis correction and prevention of tibial slope increases.

METHODS

In this historically controlled study, patients with medial osteoarthrosis and genuvarum underwent HTO between 2004 and 2012; the first 20 were operated with the conventional technique, using pre-planning correction by the Dugdale method and 18 further patients were operated with the navigation system introduced in our hospital.

RESULTS

The two groups were similar for pre-operative mechanical axis (mean 8.10 ± 3.14 for the control and 6.60 ± 2.50 for the navigated group), pre-operative tibial slope (mean 8.95 ± 3.47 versus 8.17 ± 3.11, respectively) and Lyshom score (40.85 ± 15.46 and 44.83 ± 16.86). After surgery, the control group presented mean mechanical axis of 3.35 ± 3.27, tibial slope of 13.75 ± 3.75 and Lyshom score of 87.60 ± 11.12. The navigated group showed a postoperative mechanical axis mean of 3.06 ± 1.70, tibial slope of 10.11 ± 0.18 and Lyshom score of 91.94 ± 11.61.

CONCLUSIONS

The navigation system allowed a significantly better control of tibial slope. Patients operated with the navigation system had significantly better Lysholm scores.

Computer-assisted navigation in orthopedic surgery

Computer-assisted navigation has a role in some orthopedic procedures. It allows the surgeons to obtain real-time feedback and offers the potential to decrease intra-operative errors and optimize the surgical result. Computer-assisted navigation systems can be active or passive. Active navigation systems can either perform surgical tasks or prohibit the surgeon from moving past a predefined zone. Passive navigation systems provide intraoperative information, which is displayed on a monitor, but the surgeon is free to make any decisions he or she deems necessary. This article reviews the available types of computer-assisted navigation, summarizes the clinical applications and reviews the results of related series using navigation, and informs surgeons of the disadvantages and pitfalls of computer-assisted navigation in orthopedic surgery.

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.