Evaluation of a Computed Tomography–Based Navigation System Prototype for Hip Arthroscopy in the Treatment of Femoroacetabular Cam Impingement

doi:10.1016/j.arthro.2008.11.012

Arthroscopy: The Journal of Arthroscopic & Related Surgery

Volume 25, Issue 4, April 2009, Pages 382-391

https://doi.org/10.1016/j.arthro.2008.11.012 Get rights and content

Purpose

The purpose of this study was to investigate the impact of a new computed tomography–based computer navigation system on the accuracy of arthroscopic offset correction in patients with cam type femoroacetabular impingement (FAI), and to evaluate if the accuracy of offset restoration compromises the early clinical outcome.

Methods

We prospectively treated 50 patients (25 navigated and 25 non-navigated) by hip arthroscopy and arthroscopic offset restoration for cam FAI. The patients were a mean age 42.9 years, and the average follow-up was 26.7 months, with no patients lost to follow-up. Magnetic resonance imaging scans were performed preoperatively and 6 weeks postoperatively. A postoperative alpha angle of less than 50° or a reduction of the alpha angle of more than 20° was considered to be successful offset restoration. Outcomes were measured with a visual analogue scale for pain, range of motion, and the nonarthritic hip score.

Results

The mean alpha angle improved from 76.5° (range, 57° to 110°) to 54.2° (range, 40° to 84°). In both the navigated and the non-navigated groups, 6 patients (24%) showed insufficient offset correction. Range of motion, visual analogue scale for pain scores, and nonarthritic hip scores significantly improved in all subgroups. Statistical analysis showed no significant difference regarding the clinical outcome between patients with sufficient and insufficient correction of the alpha angle.

Conclusions

In this series, a significant percentage of patients (24%) showed an insufficient correction of the alpha angle after hip arthroscopy for cam FAI. This study shows that the presented navigation system could not improve this rate and that the insufficient accuracy of reduction of the alpha angle does not appear to compromise the early clinical outcome.

Level of Evidence

Level II, prospective comparative study.

Section snippets

Methods

This prospective study was performed with the approval of our institution's human subjects’ review board. Between 2004 and 2006, a total of 83 patients were treated in our department by hip arthroscopy for femoroacetabular cam, mixed, and pincer impingement. Fifty patients (25 navigated and 25 non-navigated; 39 male and 11 female) treated by arthroscopic head–neck osteoplasty for cam type FAI were included in this study and were followed over a mean period of 26.5 months (range, 14 to 39

Results

No patients were lost to follow-up. The mean anterior alpha angle improved from 76.5° (range, 57° to 110°) to 54.2° (range, 40° to 84°; Table 1). In the group of patients treated by non-navigated arthroscopy, 6 patients (24%) showed an insufficient postoperative reduction of the alpha angle, and only 8 patients showed a postoperative alpha angle of less than 50°. In the navigated group, 6 patients (24%) showed an insufficient offset correction (Table 2), with 13 patients reaching a

Discussion

In this study, a significant number of patients (24%) showed insufficient postoperative correction of the anterior alpha angle after arthroscopic head–neck osteoplasty for cam FAI. In an earlier series, Stähelin et al.¹⁵ found a rate of 18% (4 of 22 patients) after treating a comparable collective of patients with the same technique.

In this trial, the rate of hips with insufficient correction of the alpha angle could not be improved by the CT-based computer navigation system. The software did

Conclusions

In this series a significant number of patients (24%) showed an insufficient correction of the alpha angle after hip arthroscopy for cam FAI. This study has shown that the presented navigation system could not improve this rate and that the insufficient accuracy of reduction of the alpha angle does not appear to compromise the early clinical outcome.

Acknowledgment

The authors thank BrainLAB AG, Feldkirchen, Germany, for their technical support during the development of the presented navigation software.

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Cited by (71)

Intraoperative Automated Radiographic Visualization Tool Allows for Higher Accuracy of Cam Lesion Resection When Used by Novice Surgeons for Arthroscopic Femoroplasty: Lowering the Learning Curve
2022, Arthroscopy - Journal of Arthroscopic and Related Surgery
To compare the accuracy of conventional fluoroscopy versus an intraoperative radiographic visualization tool in assisting a novice and experienced hip arthroscopist in comprehensive cam correction to a desired alpha angle (AA).
A cadaveric study was performed using 28 hemi-pelvises with cam-type deformity (AA > 55˚) measured on anteroposterior, lateral, and Dunn-view radiographs. Two fellowship-trained hip arthroscopists each performed 14 arthroscopic femoroplasties. The specimens were randomly assigned: 14 of the procedures were performed by the experienced surgeon, with 7 using the automated radiographic visualization tool (Guided Femoroplasty) and 7 using routine fluoroscopy (Control). The same number of hips was assigned to the novice surgeon, completing 7 femoroplasties with and without the visualization tool. Each hip was imaged before and after femoroplasty in 6 different positions using intraoperative fluoroscopy to evaluate head-neck offset. Femoroplasty AAs were compared between groups with and without visualization tool use, as well as between surgeons. One-way analysis of variance analysis was performed to evaluate the consistency of cam resection.
For the experienced hip arthroscopist, comparison of Guide Femoroplasty and Control groups resulted in similar accuracy when compared to the controls, with post-femoroplasty AA averages ranging from 41.4° ± 3.8˚ to 44.8° ± 2.8˚ (P = .511) and 40.2° ± 5.3˚ to 45.6° ± 2.2˚ (P = .225), respectively. For the novice hip arthroscopist, the Guided Femoroplasty group had higher accuracy, with post-femoroplasty AA averages ranging from 42.8° ± 2.6˚ to 46.1° ± 7.2˚(P = .689) with and 39.8° ± 3.1˚ to 51.9° ± 8.1˚ (P = .001) without the visualization tool. Comparison of procedure time did not show any statistically significant difference between the use of the radiographic visualization tool and controls for either surgeon (P > .05 for all).
Femoroplasty with and without the use of automated radiographic visualization tool results in accurate cam resection when used by both the experienced and novice surgeon. However, higher accuracy was observed when resecting to a desired AA performed by a novice surgeon using the visualization tool. Additionally, use of the visualization tool did not result in longer procedure times for either surgeon.
The impact of incomplete cam resections and over-resection on patient outcomes in the literature has led to the recent development of automated intraoperative radiographic visualization tools that allow for assistance of cam resection accuracy for the treatment of femoroacetabular impingement syndrome. This cadaveric study demonstrates that femoroplasty with the use of an intraoperative automated radiographic visualization tool may result in more accurate cam resections.
Intraoperative Computer Vision Integrated Interactive Fluoroscopy Correlates With Successful Femoroplasty on Clinic-Based Radiographs
2021, Arthroscopy - Journal of Arthroscopic and Related Surgery
To quantitatively evaluate computer vision interface (CVI)-guided femoroplasty in the arthroscopic treatment of femoroacetabular impingement syndrome and compare those results with traditional unguided resections.
Consecutive patients undergoing hip arthroscopy for femoroacetabular impingement syndrome between July 2019 and October 2019 were evaluated. Cases with CVI were identified along with controls, consisting of patients from the same study period who underwent surgery without the CVI and were balanced for age, sex, laterality, and preoperative alpha angles. Alpha angles were measured on pre- and postoperative clinic radiographs, as well as intraoperatively for the CVI group. Cam resections were quantified by measuring pre- and postresection alpha angles and compared between groups. The correlation between CVI views and office-based radiographs was assessed, and the 3 CVI views that best correlated with each of the 3 standard clinic radiographs were evaluated for accuracy and performance in detection of cam deformity with alpha angle ≥48° with the clinic-based films as the reference.
A total of 49 patients (51 hips) (average age, 28.7; 33 female patients) in the CVI group, and 51 patients (51 hips) (average age: 29.9; 35 female patients) in the control group. There were no significant differences between groups with respect to age, sex, laterality, or preoperative alpha angle (all P > .05). Significant alpha angle reduction occurred on all intraoperative and postoperative clinic views (all P < .01). The CVI views that best correlated with the clinic radiographs were 11:45 with the anteroposterior (ρ = 0.588, P = .0025), 12:30 with the Dunn lateral (ρ = 0.632, P = .0009), and 1:45 with the false-profile (ρ = 0.575, P = .0033). Greater reliability was observed with 12:30/Dunn (accuracy = 83.33%, P < .0001; sensitivity = 77.14%; specificity = 87.76%) and 1:45/false-profile (accuracy = 82.35%, P = .0051; sensitivity = 81.82%; specificity = 82.61%) than with 11:45/anteroposterior (accuracy = 69.15%, P = .0077; sensitivity = 56.10%; specificity = 79.25%).
CVI-guided cam resection results in successful resection of proximal femur cam lesions and represents a femoroplasty templating method that does not require preoperative computed tomography imaging or additional invasive intraoperative referencing modules. The accuracy and adequacy of this resection was validated by comparison with routine clinic radiographs.
Therapeutic Level III: retrospective comparative analysis.
Use of a 3D virtual dynamic hip model to quantify the amount of osteoplasty required in femoroacetabular impingement patients
2021, Clinical Imaging
Compare required osteoplasty predicted by a 3D virtual dynamic hip model in femoroacetabular impingement patients to actual osteoplasty performed.
Retrospective study on 20 consecutive FAI patients with a preoperative CT who underwent arthroscopy from October 2016 to September 2017. A 3D virtual dynamic hip model was created from the CT. The model displayed virtual osteoplasty depth required to restore physiologic range of motion on an osteoplasty map. Depths of virtual osteoplasty and actual osteoplasty at surgery were compared and correlated with alpha angle, lateral center edge angle, femoral version, and acetabular version.
Actual femoroplasty depth correlated with alpha angle (r = 0.85, p ≤ 0.001) and actual acetabuloplasty depth correlated with lateral center edge angle (r = 0.83, p < 0.001). Virtual osteoplasty depth did not correlate with alpha angle (p = 0.25), lateral center edge angle (p = 0.50), femoral version (p = 0.09), or acetabular version (p = 0.09). The 3D model predicted a mean virtual osteoplasty of 6.2 ± 0.3 mm compared to mean actual osteoplasty of 5.9 ± 1.1 mm. There was no significant difference between the two means (p = 0.26), though there was a significant difference in variance (p = 0.001). There was poor test reliability between virtual osteoplasty compared with actual osteoplasty (ICC = 0.30).
3D model predicted virtual osteoplasty depths varied with actual osteoplasty and was independent of 2D measurements.
Validation of the registration accuracy of navigation-assisted arthroscopic débridement for elbow osteoarthritis
2019, Journal of Shoulder and Elbow Surgery
The identification and precise removal of bony impingement lesions during arthroscopic débridement arthroplasty for elbow osteoarthritis is technically difficult. Surgical navigation systems, combined with preoperative 3-dimensional (3D) assessment of bony impingements, can provide real-time tracking of the surgical instruments and impingement lesions. This study aims to determine the registration accuracy of the navigation system for the humerus and ulna during elbow arthroscopy.
We tested the registration procedure using resin bone models of 3 actual patients with elbow osteoarthritis. We digitized bone surface points using navigation pointers under arthroscopy. We initially performed paired-point registration, digitizing 6 preset anatomical landmarks, and then refined the initial alignment with surface matching registration, digitizing 30 points. The registration accuracy for each trial was evaluated as the mean target registration error in each reference marker. Three observers repeated the registration procedure 5 times each with the 3 specimens (total, 45 trials). The median of the registration accuracy was evaluated in total (45 trials) as the accuracy of the registration procedure. The differences in the registration accuracy among the 3 observers (median of 15 trials) were also examined.
The total registration accuracies were 0.96 mm for the humerus and 0.85 mm for the ulna. No significant differences were found in the registration accuracy for the humerus and ulna among the 3 observers.
This arthroscopic-assisted registration procedure is sufficiently feasible and accurate for application of the navigation system to arthroscopic débridement arthroplasty in clinical settings.
Computer-Assisted Hip Arthroscopic Surgery for Femoroacetabular Impingement
2018, Arthroscopy Techniques
Precise osteochondroplasty is key for success in hip arthroscopic surgery, especially for femoroacetabular impingement (FAI) caused by cam or pincer morphology. In this Technical Note, we present computer-assisted hip arthroscopic surgery for FAI, including preoperative planning by virtual osteochondroplasty and intraoperative computer navigation assistance. The important concept of this technique is that navigation assistance for osteochondroplasty is based on planning made by computer simulation analysis. The navigation assistance allows us to perform neither too much nor too little osteochondroplasty. Specifically, computer simulation was used to identify the impingement point. Virtual osteochondroplasty was then performed to determine the maneuvers that would improve range of motion. Thereafter, the planning data were transported to a computed tomography-based computer navigation system that directly provided intraoperative assistance. Thus, computer-assisted technology including preoperative simulation, virtual osteochondroplasty planning, and intraoperative navigation assistance may promote precise hip arthroscopic surgery for FAI.
Prevalence and Consistency in Surgical Outcome Reporting for Femoroacetabular Impingement Syndrome: A Scoping Review
2018, Arthroscopy - Journal of Arthroscopic and Related Surgery
The purposes of this review were (1) to collate and synthesize research studies reporting any outcome measure on both open and arthroscopic surgical treatment of femoroacetabular impingement (FAI) syndrome and (2) to report the prevalence and consistency of outcomes across the included studies.
A computer-assisted literature search of the MEDLINE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Embase databases was conducted using keywords related to FAI syndrome and both open and arthroscopic surgical outcomes, resulting in 2,614 studies, with 163 studies involving 14,824 subjects meeting the inclusion criteria. Two authors independently reviewed study inclusion and data extraction with independent verification. The prevalence of reported outcomes was calculated and verified by separate authors.
Between 2004 and 2016, there has been a 2,600% increase in the publication of surgical outcome studies. Patients had a mean duration of symptoms of 27.7 ± 21.5 months before surgery. Arthroscopy was the surgical treatment used in 71% of studies. The mean final follow-up period after surgery was 32.2 ± 17.3 months. Follow-up time frames were reported in 78% of studies. Ten different patient-reported outcome measures were reported. The alpha angle was reported to be measured 42% less frequently as a surgical outcome than as a surgical indication. Surgical complications were addressed in only 53% of studies and failures in 69%. Labral pathology (91% of studies reporting) and chondral pathology (61%) were the primary coexisting pathologies reported. Clinical signs, as defined by the Warwick Agreement on FAI syndrome, were reported in fewer than 25% of studies.
Most FAI syndrome patients have longstanding pain and potential coexisting pathology. Patient-reported outcome measures and diagnostic imaging are the most frequently reported outcomes. Measures of hip strength and range of motion are under-reported. It is unclear whether the inconsistency in reporting is because of lack of measurement or lack of reporting of specific outcomes in these studies. Current surgical outcomes are limited to mid-term surgical follow-up time frames and inconsistent outcome reporting.
Level IV, systematic review of Level I through IV studies.

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: The authors report no conflict of interest.

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Original ArticleEvaluation of a Computed Tomography–Based Navigation System Prototype for Hip Arthroscopy in the Treatment of Femoroacetabular Cam Impingement

Purpose

Methods

Results

Conclusions

Level of Evidence

Section snippets

Methods

Results

Discussion

Conclusions

Acknowledgment

Arthroscopy

J Arthroplasty

Arthroscopy

Arthroscopy

Oper Tech Sports Med

Arthroscopy

Femoroacetabular impingement: A cause for osteoarthritis of the hip

Clin Orthop Relat Res

Femoroacetabular impingement and the cam-effectA MRI-based quantitative anatomical study of the femoral head-neck offset

J Bone Joint Surg Br

Surgical dislocation of the adult hip a technique with full access to the femoral head and acetabulum without the risk of avascular necrosis

J Bone Joint Surg Br

Anterior femoroacetabular impingement: Part ITechniques of joint preserving surgery

Clin Orthop Relat Res

Debridement of the adult hip for femoroacetabular impingement: Indications and preliminary clinical results

Clin Orthop Relat Res

Arthroscopic management of femoroacetabular impingement: Osteoplasty technique and literature review

Am J Sports Med

Arthroscopic treatment of femoroacetabular impingement: A proposed technique with clinical experience

Instr Course Lect

Original Article
Evaluation of a Computed Tomography–Based Navigation System Prototype for Hip Arthroscopy in the Treatment of Femoroacetabular Cam Impingement