Accuracy analysis of Iso-C3D versus fluoroscopy-based navigated retrograde drilling of osteochondral lesions

Retrograde Drilling and Bone Graft for Hepple Stage V Subchondral Bone Lesion of Talus Using 3D Image-Based Navigation-Assisted Endoscopic Technique

BACKGROUND

Retrograde drilling remains technically challenging, because of the difficulty of identifying the accurate location of cysts during surgery. This study's aim was to evaluate the 3-dimensional (3D) image-based surgical navigation-assisted endoscopic retrograde drilling technique for subchondral bone lesions of the talus.

METHODS

From March 2017 to June 2020, a total of 21 cases with Hepple stage V subchondral bone lesions of the talus were treated with 3D image-based surgical navigation-assisted endoscopic retrograde drilling and bone graft technique. Arthroscopic views were categorized per Pritsch classifications. The correlation between the drilled tunnel with preoperative cystic lesions were assessed under postoperative computer tomographic (CT) scans. The American Orthopaedic Foot & Ankle Society (AOFAS) scores, visual analog scale (VAS) scores, and Foot and Ankle Ability Measure (FAAM) sports scales were evaluated at the preoperative and final consultation. All complications were recorded.

RESULTS

On postoperative CT scans, in 20 cases (95.2%), the drilled tunnel was judged to have been in the center of previous cysts. Only 9 cases (42.9%) showed intact normal cartilage (grade 0, group A); 12 cases (57.1%) had intact, but soft, cartilage (grade I, group B). The median follow-up time was 24 (24, 30) months, and at final follow-up, there were no significant differences between the mean AOFAS and VAS scores in both groups (89.0 ± 6.4 vs 88.3 ± 7.0 and 1 vs 0.5) or postoperative FAAM sports scales (28.2 ± 2.2 vs 26.6 ± 4.9, P = .363). Two patients had revision surgery in group B.

CONCLUSION

The 3D image-based surgical navigation-assisted endoscopic retrograde drilling and bone graft technique for the subchondral bone lesions of the talus in this small case series showed encouraging results.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Management of Subchondral Lesions in the Foot and Ankle

The treatment of subchondral lesions is an area with limited focus within the foot and ankle literature. The literature has shown an association between disruption of the subchondral bone plate and the formation of subchondral cysts. The primary causes of subchondral lesions are acute trauma, repetitive microtrauma, as well as idiopathic means. Evaluation of these injuries should be done carefully and often requires advanced imaging including MRI and computed tomography. Treatment does vary depending on the presentation of the subchondral lesion with or without the presence of an osteochondral lesion.

Electromagnetic navigation reduces radiation exposure for retrograde drilling in osteochondrosis dissecans of the talus

Background

Retrograde drilling in osteochondrosis dissecans (OCD) is a widely used surgical intervention. A radiation-free electromagnetic navigation system (ENS)-based method was compared with the standard freehand fluoroscopic (SFF) method regarding clinical applicability.

Methods

We performed a clinical cohort study at a department of Orthopaedics in a Level 1 children’s hospital with 40 patients (20 SFF and 20 ENS). Retrograde drilling of the talar dome was used in patients with unstable medial OCD (MRI stage 2 according to Hepple’s revised classification; stage 2 according to the International Cartilage Repair Society). The outcome measurements were: (a) Intraoperative fluoroscopy exposure and length of surgery and (b) Postoperative serial follow-up MRIs every 6 months.

Results

22 female and 18 male patients aged 13.8 ± 1.6 years (range: 11–17 years) were included. Using the ENS technique, length of surgery was significantly reduced to 20.2 ± 6.4 min compared to 36.1 ± 11.8 min (p < 0.01) for the SFF technique. The average x-ray radiation time for the SFF technique was 23.5 ± 13.5 sec and 1.9 ± 1.7 sec for the ENS technique (p < 0.01). Radiation exposure was significantly reduced from 44.6 ± 19.7 mSv (SFF technique) to 5.6 ± 2.8 mSv (ENS technique) (p < 0.01). Intraoperative perforation of cartilage occurred once in the SFF group. Correct placement of the drilling channel was verified in all patients on follow-up MRI after six months and a timely healing was seen after two years.

Conclusions

The ENS method provides for a significant reduction in length of surgery and radiation exposure. ENS was without intraoperative cartilage perforation. The clinical and radiological follow-up parameters are comparable for SFF- and ENS-guided retrograde drilling.

Trial registration

WF – 085/20, 05/2020 “retrospectively registered” https://www.aerztekammer-hamburg.org/ethik_kommission.html.

Nontraumatic avascular necrosis of the femoral head : Arthroscopic and navigation-supported core decompression

OBJECTIVE

The aim is to address core decompression and pathologies of the femoral head, treating them during the same procedure. Furthermore, radiation exposure will be reduced.

INDICATIONS

Femoral head necrosis ARCO (Association Research Circulation Osseous) stages I-III.

CONTRAINDICATIONS

Progressive femoral head necrosis as ARCO stages IIIC-IV.

SURGICAL TECHNIQUE

Arthroscopically navigated core decompression of the femoral head using an established optoelectronic system with fluoro-free software module. First, hip joint arthroscopy was performed and further pathologies were treated. Second, core decompression was navigated by a navigation pointer and drill sleeve to reach the correct target point. After visualization, the procedure is repeated 3-5 times.

POSTOPERATIVE MANAGEMENT

Limited weight bearing of the operated leg (20 kg) for 10-14 days. Active or passive continuous motion machine for 4 weeks. Adjuvant postoperative indomethacin therapy for 10 days to reduce pain and bone marrow edema.

RESULTS

From May 2018 to January 2019, 7 patients (male = 4; 40 ± 9 years) underwent arthroscopically navigated core decompression with 2 (29%) and 5 (71%) patients being classified as ARCO II and III, respectively. Preoperatively, all patients reported load-dependent pain. In all cases, we could identify synovitis, which results in soft tissue release and synovectomy. Furthermore, 4 of 7 patients had an additional labrum lesion, which is addressed by refixation or shrinking.

DISCUSSION

Compared to the conventional technique, this fluoro-free navigation procedure allows more precise drilling. Moreover, additional pathologies, as found in all our cases, could be simultaneously addressed. The intraoperative radiation exposure for the patient and surgical team could also be reduced. Although arthroscopically assisted core decompression requires more preparation time, there are advantages over conventional surgery.

Subchondral Pathology: Proceedings of the International Consensus Meeting on Cartilage Repair of the Ankle

BACKGROUND

The evidence supporting best practice guidelines in the field of cartilage repair of the ankle are based on both low quality and low levels of evidence. Therefore, an international consensus group of experts was convened to collaboratively advance toward consensus opinions based on the best available evidence on key topics within cartilage repair of the ankle. The purpose of this article is to report the consensus statements on "Subchondral Pathology" developed at the 2017 International Consensus Meeting on Cartilage Repair of the Ankle.

METHODS

Seventy-five international experts in cartilage repair of the ankle representing 25 countries and 1 territory were convened and participated in a process based on the Delphi method of achieving consensus. Questions and statements were drafted within 11 working groups focusing on specific topics within cartilage repair of the ankle, after which a comprehensive literature review was performed and the available evidence for each statement was graded. Discussion and debate occurred in cases where statements were not agreed upon in unanimous fashion within the working groups. A final vote was then held, and the strength of consensus was characterized as follows: consensus, 51% to 74%; strong consensus, 75% to 99%; unanimous, 100%.

RESULTS

A total of 9 statements on subchondral pathology reached consensus during the 2017 International Consensus Meeting on Cartilage Repair of the Ankle. No statements achieved unanimous support, but all statements reached strong consensus (greater than 75% agreement). All statements reached at least 81% agreement.

CONCLUSIONS

This international consensus statements regarding subchondral pathology of the talus derived from leaders in the field will assist clinicians in the assessment and management of this difficult pathology.

Detection of primary screw perforation in locking plate osteosynthesis of proximal humerus fracture by intra-operative 3D fluoroscopy

PURPOSE

The purpose of this study was to identify the rate of primary screw perforations after osteosynthesis of proximal humerus fractures with intra-operative 3D fluoroscopy and to analyse the rate of secondary screw perforations as well as complications, outcome, and revision surgeries after a minimum of 12 months.

MATERIALS AND METHODS

Thirty-three patients (20 female, 13 male, median age 67 years, range 35-85 years) with displaced proximal humerus fractures were included. After reduction and fixation, an intra-operative 3D fluoroscopy was performed to evaluate primary screw perforations (PS) and screws with "near perforation" (nPS). These screws were changed intra-operatively. Patients were followed-up for a minimum of 12 months. Clinical and radiological parameters, such as secondary screw perforation, secondary loss of reduction, or functional outcome, were investigated.

RESULTS

In six patients (18.2%), humeral head screws were changed due to primary PS (n = 2) or nPS (n = 4) after the intra-operative 3D fluoroscopy. Follow-up revealed an adapted constant score (%CMS) of 76.2% after a mean follow-up of 17.7 months. Two secondary screw perforations were observed (6%). Loss of reduction was observed in eight patients (24.2%).

CONCLUSION

The intra-operative 3D reveals a high rate of primary screw perforations or near perforations. Immediate change of these screws may lead to a lower rate of secondary screw perforations and, therefore, reduce post-operative complications.

Comparison Perioperative Factors During Minimally Invasive Pre-Psoas Lateral Interbody Fusion of the Lumbar Spine Using Either Navigation or Conventional Fluoroscopy

STUDY DESIGN

Retrospective clinical study.

OBJECTIVES

The aim of this study was to compare intraoperative conditions and clinical results of patients undergoing pre-psoas oblique lateral interbody fusion (OLIF) using navigation or conventional fluoroscopy (C-ARM) techniques.

METHODS

Forty-two patients (22 patients by navigation and 20 by fluoroscopy) underwent the OLIF procedure at 2 medical centers, and records were reviewed. Clinical data was collected and compared between the 2 groups. Patients were followed-up with a range of 6 to 24 months.

RESULTS

There were no significant differences on demographic data between groups. The navigation group had zero radiation exposure (RE) to the surgeon and radiation time compared to the C-ARM group, with total RE of 44.59 ± 26.65 mGy and radiation time of 88.30 ± 58.28 seconds (P < .05). The RE to the patient was significantly lower in the O-ARM group (9.38 mGy) compared to the C-ARM group (44.59 ± 26.65 mGy). Operating room time was slightly longer in the navigation group (2.49 ± 1.35 hours) compared to the C-ARM group (2.30 ± 1.17 hours; P > .05), although not statistically significant. No differences were found in estimated blood loss, length of hospitalization, surgery-related complications, and outcome scores with an average of 8-month follow-up.

CONCLUSIONS

Compared with C-ARM techniques, using navigation can eliminate RE to surgeon and decrease RE to the patient, and it had no significant effect on operating time, estimated blood loss, length of hospitalization, or perioperative complications in the patients with OLIF procedure. This study shows that navigation is a safe alternative to fluoroscopy during the OLIF procedure in the treatment of degenerative lumbar conditions.

Management of Osteochondral Lesions of the Talar Dome

Osteochondral lesion of the talus (OLT) is a common condition associated with ankle injury that brings challenges in the diagnosis and treatment. Symptoms related to this condition are nonspecific including pain, swelling, stiffness, and mechanical symptoms of locking and catching. While the natural history of the OLTs is not well understood, surgical treatment is often required especially in chronic cases and acute cases with displaced articular fragments. Arthroscopic treatment of the OLTs aims to restore ankle joint function and pain relief by the removal of the chondral or osteochondral fragment, debridement and stabilization of cartilage rim and subchondral bone, and stimulate healing of the bone and damaged cartilage. In patients with a large lesion or after a failure of previous bone marrow stimulation, biologic restoration techniques including the use of particulate juvenile cartilage techniques, autogenous chondrocyte implantation, and osteochondral autograft or allograft transplantation may have role. This article summarizes the contemporary concepts in the clinical evaluation and treatment of OLTs with particular emphasis on surgical strategies.

Image-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation: a cadaver study

BACKGROUND

Reconstruction of the coracoclavicular ligament functions to restore anatomic alignment of the clavicle and may improve biomechanical function and clinical outcomes. Improper placement of the coracoclavicular tunnel may inherently weaken the coracoid. The purpose of this study was to evaluate the feasibility and accuracy of navigated image-free placement of K-wires for coracoclavicular tunnel position in comparison to conventional drill guide-based placement.

MATERIALS AND METHODS

Eight human shoulder specimens were assigned for conventional technique with a coracoclavicular guide device (group CP) and the paired contralateral side for the navigated procedure (group NP) with an optoelectronic system with a fluoro-free software module. First-pass accuracy (%) and the K-wire trajectory (lateral-center orientation (LC), center-center (CC) orientation and medial-center orientation (MC) were measured.

RESULTS

In all navigated K-wires a 100 % first-pass accuracy was observed. In three of the eight (37.5 %) specimens of the drill guide-based group, drilling had to be repeated. One of them had to be repeated twice, resulting in eight versus twelve drillings for the navigated versus conventional group, respectively (p = 0.021). K-wire trajectory showed an MC orientation in most of the specimen (n = 9, group NP 4, group CP 5).

CONCLUSIONS

Image-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation has higher first-pass accuracy in comparison to conventional drill guide-based placement and, therefore, may enable a precise anatomic position of the drill holes and reduce the risk of an iatrogenic coracoid fracture.

Isocentric C-arm three-dimensional navigation versus conventional C-arm assisted C1-C2 transarticular screw fixation for atlantoaxial instability

OBJECTIVE

The Isocentric C-arm 3D navigation has been widely used in superior cervical surgeries in recent years. Several clinical researches reported that navigation system was an effective support device for treatment of atlantoaxial instability. But there were few studies about the advantages of navigation system compared to conventional C-arm fluoroscopy in C1-C2 transarticular screw fixation for atlantoaxial instability. The aim of the study was to evaluate the precision of computer-assisted C1-C2 transarticular screw fixation (Magerl's technique) for atlantoaxial instability and compare the clinical results with conventional C-arm fluoroscopy.

METHODS

Forty-two patients diagnosed as atlantoaxial instability who underwent C1-C2 transarticular screw fixation under two different fluoroscopy methods were studied. The Iso-C 3D navigation group included 18 patients and the other 24 patients were in the conventional C-arm group. The clinical and radiographic results were recorded and compared between the two groups. Patients were followed up with clinical examination and radiographs at a mean of 18.4 months.

RESULTS

There were no significant differences between two groups in the mean age, gender, and causes of atlantoaxial instability. The mean blood loss in the navigation group was 236.1 ± 28.5 mL versus 308.3 ± 21.2 mL in the conventional C-arm group. The radiation time was significantly reduced using 3D navigation (48.8 ± 1.05 s versus 60.3 ± 2.23 s). Overall, 97.2 % (35/36) of 3D navigated screws and 91.7 % (44/48) of fluoroscopy screws were placed into the C1-C2 transarticular passages. Thirty-nine of forty patients showed evidence of solid fusion after 12 months on cervical plain radiographies or CT scans.

CONCLUSIONS

On comparing the two imaging techniques, it was found that using Iso-C 3D navigation can improve accuracy of the C1-C2 transarticular screws, decrease intra-operative fluoroscopic time and blood loss, and not prolong the operative time. This study demonstrates that Iso-C 3D navigation is a safe and effective means of guiding C1-C2 transarticular screw fixation for atlantoaxial instability.

A novel computer navigation system for retrograde drilling of osteochondral lesions

Osteochondritis dissecans (OCD) represents an important clinical entity in orthopedic sports medicine. Once surgical intervention is required, retrograde drilling for OCD lesions remains technically challenging. A novel electromagnetic navigation system was developed to be a radiation-free navigation tool providing spatiotemporal real-time information to the surgeon without the need for a stationary patient tracker and without relevant setup and calibration times. The novel system was tested for arthroscopically assisted retrograde drilling of cadaveric OCD lesions of the knee and talus and compared with the gold standard fluoroscopy-guided retrograde drilling procedure in a controlled laboratory study setup. The novel method considerably improves on the standard operating procedure in terms of safety, operation time, and radiation exposure and will be available for further surgical indications.

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.

Managing the cystic osteochondral defect: allograft or autograft

Osteochondral lesions of the talus are generally benign, and many heal or are not symptomatic. A subset of these defects progress to large cystic lesions, which have a less favorable prognosis. The treatment options are joint preservation or sacrifice. Joint salvage entails marrow stimulation techniques or hyaline cartilage replacement with allograft or autograft. When lesions reach greater than 3 cm(2) or Raikin class IV or become uncontained on the shoulders of the talus, autografting techniques become more challenging. Osteochondral allografting may be a better surgical option, often achievable without a malleolar osteotomy for exposure.

Arthroscopically assisted retrograde drilling for osteochondritis dissecans (OCD) lesions of the knee

PURPOSE

Accurate retrograde drilling for osteochondritis dissecans lesions remains technically challenging. A novel, radiation-free method using an electromagnetic guidance system was developed, and its feasibility and accuracy for retrograde drilling procedures evaluated in an experimental setting.

METHODS

Sixteen arthroscopically assisted, electromagnetically guided retrograde drilling procedures were performed in 4 human cadaveric knee joints. Therefore, two artificial cartilage lesions were set consecutively on each condyle. Final drill bit position was documented in two planes using fluoroscopy. Subsequently, drilling accuracy was measured in terms of distance from the final position of the drill bit to the articular cartilage surface (D1), and distance between the tip of the drill bit to the centre of the cartilage lesion on the articular cartilage surface (D2). All procedures were timed using a stopwatch.

RESULTS

Successful retrograde drilling was accomplished in all 16 cases. The overall mean time for the retrograde drilling procedures was 361.6 ± 34.7 s. Mean D1 was 2.2 ± 0.5 mm; mean D2 was 0.8 ± 0.7 mm. No complications occurred.

CONCLUSIONS

The novel electromagnetic guidance system used in this study showed accurate targeting results, required no radiation, was associated with no complications and demonstrated user-friendliness.

LEVEL OF EVIDENCE

II.

Retrograde drilling of talar osteochondritis dissecans lesions: a feasibility and accuracy analysis of a novel electromagnetic navigation method versus a standard fluoroscopic method

PURPOSE

A novel method using an electromagnetic navigation system (ENS) was developed, and its feasibility and accuracy for retrograde drilling procedures were evaluated and compared with the standard freehand fluoroscopic method in an experimental setting.

METHODS

A controlled laboratory study of 16 standard freehand fluoroscopically guided and 16 electromagnetically navigated retrograde drilling procedures was performed on 4 cadaveric human ankle joints. Four artificial cartilage lesions were consecutively set, 2 on the medial and 2 on the lateral talar dome. Drilling accuracy was measured in terms of the distance from the final position of the drill bit to the tip of the probe hook and the distance between the tip of the drill bit and the center of the cartilage lesion on the articular cartilage surface. Intraoperative fluoroscopy exposure times were documented, as were readjustments of drilling directions or complete restarts. All procedures were timed with a stopwatch.

RESULTS

Successful retrograde drilling was accomplished in 12 cases with the standard fluoroscopy-guided technique and in all 16 ENS-guided procedures. The overall mean time for the fluoroscopy-guided procedures was 660.00 ± 239.87 seconds and the overall mean time for the ENS method was 308.06 ± 54.03 seconds, providing a mean time benefit of 420.13 seconds. The mean distance from the final position of the drill bit to the tip of the probe hook was 3.25 ± 1.29 mm for the standard method and 2.19 ± 0.54 mm for the ENS method, and the mean distance between the tip of the drill bit and the center of the cartilage lesion on the articular cartilage surface was 2.50 ± 0.97 mm for the standard method and 0.88 ± 0.81 mm for the ENS method.

CONCLUSIONS

Compared with the standard fluoroscopic technique, the ENS method used in this study showed higher accuracy and a shorter procedure time and required no X-ray radiation.

CLINICAL RELEVANCE

The novel method considerably improves on the standard operating procedure in terms of safety, operation time, and radiation exposure.

Radiation exposure during 3D fluoroscopy of the knee: an experimental study

PURPOSE

To measure the radiation exposure at the knee and surrounding area during the use of 3D fluoroscopy.

METHODS

An experimental study was conducted by using a human cadaveric knee as a focus point for the 3D fluoroscope. An isocentric C-arm fluoroscope machine was applied on the lateral side of the knee. The radiation dosage at the focus point and surrounding area was measured. The mean radiation exposure in each location was compared between low- and high-resolution scanning.

RESULTS

The mean radiation sustained at the focus point was 44.0 ± 5.6 μSv and 20.0 ± 1.0 μSv in high- and low-resolution scanning, respectively. Radiation exposure on the opposite side of the C-arm machine was found to be higher than that on the other locations with the same distance from the focus point. In low-resolution scanning, radiation could not be detected beyond 75 cm from the focus point at the proximal, distal and same side of the machine. Radiation could be measured at a distance of up to 1.25 m on the opposite side of the machine. In high-resolution scanning, radiation could be measured at a distance of up to 1 m at the proximal, distal and same side of the C-arm, but up to 1.5 m on the opposite side.

CONCLUSION

Radiation exposure during 3D fluoroscopy of the knee decreases with increasing distance from the focus point. A higher number of scans in the high-resolution mode causes greater radiation exposure. In isocentric 3D fluoroscopy of the knee, a safe zone is located at least 1.5 m away from the focus point.

[Navigated retrograde drilling in Osteochondrosis dissecans (OCD) of the talus]

OBJECTIVE

Subchondral decompression and revascularization in Osteochondrosis dissecans (OCD) of the talus with cartilage preservation.

INDICATIONS

Symptomatic talar OCD stage I and II, i.e., cartilage intact or almost intact.

CONTRAINDICATIONS

Talar OCD stage III and IV, i.e., cartilage not intact.

SURGICAL TECHNIQUE

Diagnostic ankle arthroscopy. Insertion of dynamic reference base (DRB) in the talar neck through a stab incision. After 3D image acquisition and planning of the drilling, navigated drilling with a 5 mm drill. Insertion of a 1 mm titanium wire into the canal and 3D image acquisition for evaluation of the canal. Autologous cancellous bone transplantation into the canal. Arthroscopic evaluation.

POSTOPERATIVE MANAGEMENT

For 6 weeks, 15 kg partial weight bearing without immobilization. After 6 weeks full weight bearing.

RESULTS

A total of 52 patients with symptomatic talar OCD stage I and II were included in a clinical follow-up study. Time needed for preparation, including the placement of the DRB, scanning time, and preparation of the trajectories was 7 min 32 s (4-30 min). In 50 cases (96%), the drilling was judged with 3D imaging to be correct. In the remaining 2 cases (4%), the drilling ended in the caudal portion of the lesion. A perforation of the cartilage was not registered arthroscopically. Follow-up after 12 months (range 6-36 months) was possible in 48 patients (92%). Three patients (6%) had been converted to bone cartilage transplantation (OATS) due to recurrent symptoms. These patients were excluded from follow-up. The follow-up scores were Visual Analogue Scale Foot and Ankle (mean 93 points [range 86-100 points]) and the SF 36 (standardized to 100 point maximum, 90 points [range 79-100 points]).

Accuracy analysis of a novel electromagnetic navigation procedure versus a standard fluoroscopic method for retrograde drilling of osteochondritis dissecans lesions of the knee

BACKGROUND

Retrograde drilling for osteochondritis dissecans (OCD) remains a challenging operation.

PURPOSE

A novel radiation-free electromagnetic navigation system (ENS)-based method was developed and its feasibility and accuracy for retrograde drilling procedures evaluated and compared with the standard freehand fluoroscopic method in an experimental setting.

STUDY DESIGN

Controlled laboratory study.

METHODS

A controlled laboratory study with 16 standard freehand fluoroscopically and 16 electromagnetically guided retrograde drilling procedures was performed on 8 cadaveric human knees. Four artificial cartilage lesions (2 on each condyle) were set per knee. Drilling accuracy was determined by final distance from the tip of the drill bit to the tip of the probe hook (D1) and distance between the tip of the drill and the marked lesion on the cartilage surface (D2). Intraoperative fluoroscopy exposure times were documented, as were directional readjustments or complete restarts. All procedures were timed using a stopwatch.

RESULTS

Successful retrograde drilling was accomplished in all 16 cases using the novel ENS-based method and in 11 cases using the standard fluoroscopic technique. The overall mean time for the fluoroscopy-guided procedures was 10 minutes 55 seconds ± 3 minutes 19 seconds and for the ENS method was 5 minutes 34 seconds ± 38 seconds, providing a mean time benefit of 5 minutes 35 seconds (P < .001). Mean D1 was 3.8 ± 1.6 mm for the standard and 2.3 ± 0.6 mm using the ENS technique (P = .021), and mean D2 was 2.5 ± 1.3 mm for the standard and 0.9 ± 0.7 mm for the ENS-based method (P < .001).

CONCLUSION

Compared with the standard fluoroscopic technique, the novel ENS-based method used in this study showed superior accuracy, required less time, and utilized no radiation.

CLINICAL RELEVANCE

The novel method improves a standard operating procedure in terms of accuracy, operation time for the retrograde drilling procedure, and radiation exposure.

Percutaneous screw fixation for the acetabular fracture with quadrilateral plate involved by three-dimensional fluoroscopy navigation: surgical technique

BACKGROUND

The percutaneous three-dimensional (3D)-fluoroscopic-navigated screw directing to the quadrilateral plate was attempted.

MATERIALS AND METHODS

Five patients with acetabular fractures were treated by 3D navigated percutaneous screw. The quadrilateral plate was involved in all the patients. The Arcadis 3D (ARCADIS Orbic 3D(®); Siemens AG Healthcare Sector, Erlangen, Germany) and computer navigation system (stryker navigation system) were employed, screwing trajectory was attempted to anchor the quadrilateral plate perpendicularly to the fracture line and close to the joint cartilage as much as possible. Parameters including fracture gap closure (P1), distance to the joint cartilage (P2), angulations between the screw and the fracture line (P3), were measured with the software installed on the machine of Arcadis 3D.

RESULT

Seven screws were inserted with the use of 3D fluoroscopic navigation. The quadrilateral plate was hold by percutaneous screws. The closure of fracture gap was achieved in 3 patients by 2-3mm. The nearest distance from the screw to the joint cartilage was ranged from <1mm to 6mm. The angulations between the screw and the fracture line was 80-90° in three patients, it was 60° and 65° respectively on the rest two patients. All patients felt pain free 1week after the operation. No complication was noted postoperatively.

CONCLUSION

The surgical technique of percutaneous screwing for the acetabular fracture with three-dimensional fluoroscopy-based navigation was demonstrated.

Anterior single screw fixation of odontoid fracture with intraoperative Iso-C 3-dimensional imaging

PURPOSE

The purpose of this study was to assess the value of isocentric C-arm three-dimensional (Iso-C 3D) fluoroscopy for the insertion of an anterior odontoid screw. The results of the Iso-C 3D group were compared with that of an historic control group using conventional fluoroscopy.

METHODS

Twenty-nine patients diagnosed with type II or rostral-type III odontoid fractures were treated with a single anterior screw fixation in this study. The Iso-C 3D group included 13 patients and the other 16 patients were in the historic control group. All operations were performed by a single surgeon using standard procedure and manner. The clinical and radiographic results were recorded and compared between the two groups.

RESULTS

The fluoroscopy time in the Iso-C 3D group was 42.9 s as compared to 68.1 s in the control group (P < 0.01). The mean operative time was 91.5 min in the Iso-C 3D group when compared with 81.6 min in the control group (P = 0.20). The rate of bony fusion was 96.6% (28/29), the failure rate of reduction or fixation was 13.8% (7.7% in Iso-C 3D group; 18.8% in control group). The Smiley-Webster scale showed that 90% of patients achieved good or better outcomes

CONCLUSIONS

In conclusion, this technique can be safely extended to the treatment of technically difficult to treat spinal injuries and at the same time reduce total radiation exposure time both for the patient and the surgeon.

Navigated reconstruction of a tibial plateau compression fracture post-virtual reconstruction: a case report

Post-traumatic arthrosis is a common problem following tibial plateau fractures. Computed tomography (CT) with 3D reconstruction is essential in facilitating accurate analysis of the fracture type and depth of compression, but is typically only available pre- or postoperatively. Special reconstruction software tools, based on 3D imaging, have been developed. Limiting factors include a lengthy preoperative planning phase. This study assessed a specific type of navigation software, which is currently in use in maxillofacial surgery, to establish whether it might play a critical role in orthopaedic procedures. We report the case of a 43 year old female who sustained an isolated tibial plateau compression fracture (Schatzker IIIa), and who was successfully treated with open reduction and internal fixation, with the aid of intraoperative 3D imaging and new software navigation tools. This case demonstrates a combined approach using a new software tool based on intraoperative fluoroscopy-3D imaging.

Feasibility of a navigated registration technique in FAI surgery

INTRODUCTION

Arthroscopic femoral osteoplasties might be technically demanding, might cause prolonged operative times and restrict the intraoperative overview. An automated navigated matching process of preoperative CT-data and intraoperative fluoroscopy should allow for noninvasive registration for FAI-surgery.

METHOD

Six hip joints were used with a conventional navigation system. Defined osseous lesion (2 × 2 mm) in the femoral neck, head neck junction, and head region were created followed by automated segmentation including CT-fluoro image fusion by the navigation system. Precision of registration process was tested trough a lateral arthroscopic portal. In vivo distances between pointer tip to bone were measured. Secondary in vivo distances between an inserted navigated shaver and the osseous lesions were measured.

RESULTS

Our results allow a CT-fluoroscopy matching procedure for noninvasive registration process for navigated FAI-surgery in multiplanar planes. Precision is more accurate at the femoral neck and head-neck junction than at the femoral head area.

CONCLUSION

Future navigated applications might simplify and increase precision of FAI-surgery.

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.

Navigated scaphoid screw placement using customized scaphoid splint: an anatomical study

INTRODUCTION

Accuracy in navigated surgery depends on placement and registration of stable reference markers close to the anatomic region of interest. Navigation in small and complex anatomic regions, such as the scaphoid, is challenging due to difficulties in placing a stable reference marker. In the current paper, we describe the use of a customized wrist-positioning device "Scaph-splint" with a built-in reference marker that facilitates navigated scaphoid screw insertion in combination with a 3D imaging device.

MATERIALS AND METHODS

Initial cadaveric feasibility study Five fresh-frozen cadaveric upper extremity specimens were utilized. Each specimen was secured onto the "Scaph-splint" with the wrist in about 90 degrees of extension. Using a 3D fluoroscope, a series of images were taken of the carpal bones and reconstructed in axial, sagittal, and coronal planes. Navigated planning and guidance of scaphoid drilling and screw placement was performed. Next, a repeat 3D scan was taken to analyze the drill canal. The accuracy of navigated scaphoid drilling, drilling trials, and any penetration of the scaphoid outside of the planned drill trajectory were evaluated. A grading scheme was used to assess the drilling accuracy: Grade 1 <1 mm deviation, Grade 2 <2 mm deviation, Grade 3 <3 mm.

RESULTS

Scaphoid drilling was confirmed to be completely accurate (Grade 1) in two specimens, highly accurate (Grade 2) in two specimens, and accurate (Grade 3) in one specimen. No specimen required a repeat drilling of the scaphoid. In one specimen, the proximal scaphoid pole was perforated by the drill. No registration failures or loosening of the reference marker occurred.

CONCLUSION

The use of the "Scaph-splint" enabled stabilization of the hand and wrist, thus adequately fixing the reference marker in relation to scaphoid for optimal navigation and screw placement without the need to directly penetrate the scaphoid with a reference marker. The use of 3D fluoroscopy further increased the accuracy and precision of scaphoid screw placement.

Radiation- and reference base-free navigation procedure for placement of instruments and implants: application to retrograde drilling of osteochondral lesions of the knee joint

OBJECTIVE

A novel, radiation- and reference base-free procedure for placement of navigated instruments and implants was developed and its practicability and precision in retrograde drillings evaluated in an experimental setting.

MATERIALS AND METHODS

Two different guidance techniques were used: One experimental group was operated on using the radiation- and reference base-free navigation technique (Fluoro Free), and the control group was operated on using standard fluoroscopy for guidance. For each group, 12 core decompressions were simulated by retrograde drillings in different artificial femurs following arthroscopic determination of the osteochondral lesions. The final guide-wire position was evaluated by postoperative CT analysis using vector calculation.

RESULTS

High precision was achieved in both groups, but operating time was significantly reduced in the navigated group as compared to the control group. This was due to a 100% first-pass accuracy of drilling in the navigated group; in the control group a mean of 2.5 correction maneuvers per drilling were necessary. Additionally, the procedure was free of radiation in the navigated group, whereas 17.2 seconds of radiation exposure time were measured in the fluoroscopy-guided group.

CONCLUSION

The developed Fluoro Free procedure is a promising and simplified approach to navigating different instruments as well as implants in relation to visually or tactilely placed pointers or objects without the need for radiation exposure or invasive fixation of a dynamic reference base in the bone.

Current concepts in the diagnosis and treatment of osteochondral lesions of the ankle

Osteochondral lesions of the ankle are a more common source of ankle pain than previously recognized. Although the exact pathophysiology of the condition has not been clearly established, it is likely that a variety of etiological factors play a role, with trauma, typically from ankle sprains, being the most common. Technological advancements in ankle arthroscopy and radiologic imaging, most importantly magnetic resonance imaging, have improved diagnostic capabilities for detecting osteochondral lesions of the ankle. Moreover, these technologies have allowed for the development of more sophisticated classification systems that may, in due course, direct specific future treatment strategies. Nonoperative treatment yields best results when employed in select pediatric and adolescent patients with osteochondritis dissecans. However, operative treatment, which is dependent on the size and site of the lesion, as well as the presence or absence of cartilage damage, is frequently warranted in both children and adults with osteochondral lesions. Arthroscopic microdrilling, micropicking, and open procedures, such as osteochondral autograft transfer system and matrix-induced autologous chondrocyte implantation, are frequently employed. The purpose of this article is to review the history, etiology, and classification systems for osteochondral lesions of the ankle, as well as to describe current approaches to diagnosis and management.

Initial outcomes of 3-dimensional imaging-based computer-assisted retrograde drilling of talar osteochondral lesions

BACKGROUND

In operative treatment of Berndt and Harty stage 1 and stage 2 osteochondral lesions of the talus, the goal is revascularization. The use of computer-assisted guided retrograde drilling of osteochondral lesions has been described as a new technique with promising results.

PURPOSE

This study reports the follow-up assessment of patients treated with Iso-C-3D-navigated retrograde drilling. Its aim was to establish whether the greater precision of computer-assisted drilling results in satisfactory clinical outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent navigated Iso-C-3D-based retrograde drilling between June 1, 2003, and July 31, 2005, were included in the follow-up study. Clinical outcomes were measured using (1) the Ankle-Hindfoot Scale of the American Orthopaedic Foot and Ankle Society and (2) the Visual Analogue Scale-Foot and Ankle. Radiological outcomes were assessed via radiographs and magnetic resonance imaging. Surgeon satisfaction was assessed using a simple 0 to 10 rating scheme for feasibility, accuracy, and clinical benefit.

RESULTS

Average follow-up time was 25 months (range, 20-34). Twenty patients satisfied the inclusion criteria: 12 men and 8 women; mean age, 35 years (range, 19-58). One patient was excluded because he required a cartilage restoration procedure. All scores improved at the time of follow-up-Ankle-Hindfoot Scale, from 76 to 90 (P < .001); Visual Analogue Scale-Foot and Ankle, from 79 to 92 (P < .001). The average ratings of the operating surgeons (n = 3) were as follows: feasibility 9.0 (range, 7.3-10.0); accuracy, 8.5 (range, 5.8-10.0); and clinical benefit, 8.5 (5.7-10.0). At follow-up, magnetic resonance imaging revealed an improvement of the Hepple score in 80% of patients.

CONCLUSION

Arthroscopic treatment of osteochondral lesions of the talus is well established. A retrograde approach does not breach the overlying intact talar cartilage. The results of this follow-up study of 3-dimensional computer navigated drilling are promising.

Arthroscopic-assisted fluoroscopic navigation for retrograde drilling of a talar osteochondral lesion

Level of Evidence: V, Expert Opinion

3D imaging (ARCADIS)-based Computer Assisted Surgery (CAS) guided retrograde drilling in osteochondritis dissecans of the talus

Level of Evidence: V, Expert Opinion

3D imaging (ARCADIS)-based Computer Assisted Surgery (CAS) for nail placement in combined ankle and subtalar fusion

Level of Evidence: V, Expert Opinion

Current concepts and applications of computer navigation in orthopedic trauma surgery

Navigation has become widely integrated into regular endoprosthetic procedures, but clinical use of navigation systems in orthopaedic trauma has only been implemented in a few indications. Navigation systems enable an accuracy of 1 mm or 1 degree. Navigation can achieve higher precision when it is combined with different imaging modalities, including preoperative computer tomography (CT), intraoperative CT, two-dimensional fluoroscopy, and, recently, intraoperative three-dimensional fluoroscopy. The precision of the navigation system can be influenced by the surgeon as well as by the camera system, type of reference marker, and the registration process. Recent developments in orthopedic trauma navigation allow for bilateral femoral anteversion measurements, noninvasive registration of an uninjured thigh, and intraoperative three-dimensional fluoroscopy-based pedicle screw placement. Although the use of navigation has provided initial positive results in trauma care, prospective clinical studies remain to be performed.