Talonavicular Arthroscopy for Osteochondral Lesions

Abstract

Background:

Traditional treatment of talonavicular osteochondral lesions (OCLs) requires an open procedure. Arthroscopic microfracture of talonavicular OCLs may provide a viable, minimally invasive approach. The purpose of this study was to describe an arthroscopic approach for treatment of talonavicular OCLs, describe the proximity of arthroscopic portals to important structures in cadaver specimens, and report magnetic resonance imaging (MRI) findings and clinical outcomes of this technique.

Methods:

Five cadaver specimens were dissected so proximity of portals to adjacent tendons and neurovascular structures could be assessed. Subsequently, 3 athletic patients with OCLs of the talonavicular joint were treated with arthroscopic debridement and microfracture. Patient records and imaging studies were retrospectively reviewed.

Results:

In the cadaver specimens, the mean distance between the neurovascular bundle and the medial border of the extensor hallucis longus (EHL) was 9.0 (range, 8 to 10) mm. The saphenous nerve was located a mean of 6.8 (range, 6 to 7) mm from the medial border of the tibialis anterior tendon. Therefore, portals were placed just medial to the EHL and tibialis anterior tendon to avoid the neurovascular bundle and saphenous nerve, respectively. In all patients, access, identification of the OCL, debridement, and microfracture were successfully performed. All patients demonstrated improvements in Foot and Ankle Outcome Scores and Short Form–12 scores and began gradual return to activity within 12 weeks following the operation. No significant complications occurred. MRI indicated signal consistent with reparative fibrocartilage in all patients.

Conclusion:

Level of Evidence:

Level IV, case series.

Keywords

talus navicular midfoot microfracture bone marrow stimulation articular cartilage outcomes

Talonavicular osteochondral lesions (OCLs) are uncommon,⁹ but when they do occur, the operative approach to facilitate treatment typically requires an open procedure and extensive soft tissue dissection. Furthermore, visualization of the most plantar aspect of the talonavicular joint requires distraction of the joint that may further strain the soft tissue envelope. Adequate blood supply is critical to the repair of talonavicular OCLs; however, this is at risk in extensive open procedures.¹⁶ This has prompted alternative methods of approach, visualization, and treatment. Talonavicular arthroscopy offers the possibility of limited soft tissue compromise and excellent visualization. A review of the literature indicated this approach has only been reported in 2 patients and revealed no previous descriptions of arthroscopic treatment for talonavicular OCLs.^4-6,8

The advantages of less invasive access prompted a review of the possibility of arthroscopic visualization of the talonavicular joint while under distraction and the subsequent treatment of OCLs of this joint. The concerns of such an approach lie in the proximity of important anatomic structures and potential damage to these structures from distraction pins or arthroscopy portals. The current authors discuss the periarticular anatomy in relation to distraction pins and arthroscopic portal placement for an arthroscopic approach. This study also describes the treatment of talonavicular OCLs with arthroscopic microfracture and reports magnetic resonance imaging (MRI) and clinical outcomes in 3 consecutive patients. Our hypothesis was that an arthroscopic approach to the talonavicular joint would provide adequate access, avoid damage to important periarticular structures, and result in successful clinical and imaging outcomes.

Methods

Anatomic Study

Five fresh frozen specimens were dissected so that proximity of portals and pin placement to adjacent tendons and neurovascular structures could be assessed. The average age of the specimens was 51 years, of which 3 of 5 were female. Two left and 3 right feet were used. The dorsomedial aspect of the ankle was exposed from the saphenous nerve to the superficial peroneal nerve from medial to lateral. Care was taken to preserve all tendons and neurovascular structures. Upon exposing the dorsomedial aspect of the foot, the saphenous nerve, tibialis anterior tendon, extensor hallucis longus (EHL), and neurovascular bundle (deep peroneal nerve, superficial peroneal nerve, and dorsalis pedis) were identified (Figures 1 and 2A). Distances from the neurovascular bundle to the medial border of the EHL and from the saphenous nerve to the medial border of the tibialis anterior tendon were measured using Castroviejo calipers (Novo Surgical, Inc, Oak Brook, IL). The ankle joint was kept in neutral while measurements were acquired. All measurements were taken at the level of the talonavicular joint. Proximity of the distraction pins to neurovascular and tendinous structures was also measured.

Figure 1.

Dorsal view of the foot after dissection of the talonavicular joint and surrounding structures. (A, dorsalis pedis artery; B, deep peroneal nerve; C, superficial peroneal nerve; D, extensor digitorum longus; E, extensor hallucis longus; F, tibialis anterior tendon; G, saphenous nerve.)

Figure 2.

Medial views of a right foot and ankle demonstrating important anatomic structures, distraction pin placement for talonavicular arthroscopy, and instrumentation for accessing the joint. (A) Medial photograph of a cadaveric specimen after dissection of the talonavicular joint and surrounding structures. (A, superficial peroneal nerve; B, deep peroneal nerve; C, dorsalis pedis artery; D, extensor hallucis longus; E, tibialis anterior tendon; F, saphenous nerve.) (B) Illustration and (C) intraoperative photograph of portal and distractor pin placement in relation to periarticular anatomy. A 1 cm medial incision was placed medial to the tibialis anterior tendon, directly over the talonavicular joint. The second incision was placed slightly less than 1 cm dorsal to the medial incision and medial to the extensor hallucis longus tendon. 1.9-mm 30-degree arthroscope and instrumentation can be alternated between portals as required.

Clinical Cases

Three patients that had an OCL of the navicular are presented. All cases were the result of trauma while taking part in an athletic activity and MRI was used in all 3 patients to confirm the size and location of the OCL. Nonoperative treatment included 6 weeks of restricted weight-bearing in a controlled ankle movement (CAM) boot followed by relative rest (ie, restriction of sports activities) and 3 months of physical therapy. Operative intervention was performed to address patient’s symptoms following failed nonoperative treatment. MRI studies were gathered using a 3 Tesla imaging system (GE Healthcare, Milwaukee, WI). T2 mapping MRI was also used to assess articular cartilage at pre- and postoperative visits. All patients met the indications for talonavicular arthroscopy, were treated with microfracture of their talonavicular OCLs, and were therefore included for study. Indications for arthroscopic intervention in the talonavicular joint include OCL, osteophytes, loose bodies, impingement, synovitis, and infection.⁸ Follow-up MRI was performed postoperatively to assess healing status. Foot and Ankle Outcome Score (FAOS) and Short Form–12 General Health Questionnaire (SF-12) surveys, which have been previously validated,^2,7,10,12 were administered at the last visit prior to operation and at each follow-up visit following the operation. Data were prospectively entered into our institution’s database. Records, imaging studies, and outcome scores of patients who underwent talonavicular arthroscopy were later reviewed retrospectively. This study, and all information included, was approved by our Institutional Review Board.

Operative Technique

All patients were positioned supine on the operative table and thigh tourniquets were placed. Two 0.062 Kirschner wires were placed within the neck of the talus and body of the navicular, respecting the anatomic landmarks described in the above anatomic dissection, and the joint was identified with use of a fluoroscopic C-arm. The Kirschner wire placed in the body of the navicular was drilled 1 cm distal to the tuberosity and at an angle no more than 5 to 8 degrees, in the transverse plane of the foot, away from the talonavicular joint to avoid disrupting the articular surfaces. A needle was used to inject 1-2 mL of saline into the joint and a medial mini-open incision approximately 1 cm in length was placed directly over the talonavicular joint medial to the tibialis anterior tendon. Subcutaneous tissue and the joint capsule were dissected using a small incision and spread technique. A 1.9-mm 30 degree arthroscope (Smith and Nephew, Inc, Andover, MA) was inserted into the medial portal and a second more dorsal incision was used to create the instrumentation portal. The dorsal portal was made slightly less than 1 cm dorsal to the first medial portal and just medial to the EHL. These structures were identified and retracted. If the EHL could not be easily identified, the tibialis anterior tendon and medial portal were used as landmarks, and the dorsal portal was placed 6-8 mm dorsolateral to the medial portal. This ensured that the dorsal portal was placed medial to the EHL. Distraction across the talonavicular joint was achieved with a Weinraub Kirschner wire type distracter (Innomed, Inc, Savannah, GA) (Figure 2). Distraction pins were placed 2-3 mm medial to the tibialis anterior tendon and 4-5 mm lateral to the saphenous nerve. The arthroscope and instrumentation were alternated between portals as required for visualization and access (Figure 2C). An appropriate approach to the lesions was selected from preoperative imaging. Operative debridement of synovial hyperplasia and removal of any loose bodies was performed initially. Once the osteochondral lesion was identified (Figure 3A), the cartilage defect was debrided with use of a spinal curette and shaver (Figure 3B). A micropick was used to perform microfracture to the subchondral bone (Figure 3C). Patients were placed in a dry, sterile bulky dressing.

Figure 3.

Arthoscopic images of a navicular osteochondral lesion through (A) a dorsal portal and (B) debridement of the joint. (C) The lesion was microfractured to facilitate clot formation and fibrocartilage infill using an awl. All images are from case 1.

Active and passive range of motion exercises were encouraged immediately for up to 1 hour per day. The patients were kept in the bulky dressing and were non-weight-bearing for the first 2 weeks. Two weeks postoperatively, the patients were placed in a CAM boot and progressed to 10% partial weight-bearing from 2 to 4 weeks. Progression to full weight-bearing was completed by increasing weight-bearing by approximately 10% each day between weeks 4 and 6. At 6 weeks, patients were enrolled in a formal physical therapy program.

Results

Anatomic Study

In all 5 specimens, the neurovascular bundle was located lateral to the EHL. The mean distance between the neurovascular bundle and the medial border of the EHL was 9.0 (range, 8 to 10) mm. The dorsal arthroscopic portal could therefore be placed just medial to the EHL to ensure avoidance of the neurovascular bundle. The saphenous nerve was located medial to the tibialis anterior tendon in all 5 specimens and mean distance from the medial border of the tibialis anterior tendon to the saphenous nerve was 6.8 (range, 6 to 7) mm. Thus, the medial portal could be placed just medial to the tibialis anterior tendon to avoid contact with the saphenous nerve. The distraction pin in the body of the navicular was a mean of 2.4 (range, 2 to 3) mm medial to the tibialis anterior tendon and a mean 3.6 (range, 3 to 4) mm lateral to the saphenous nerve. The navicular distraction pin could therefore be placed slightly medial to the tibialis anterior tendon. The distraction pin in the body of the talus was a mean of 4.8 (range, 4 to 6) mm medial to the tibialis anterior tendon and a mean 3.8 (range, 2 to 4) mm lateral to the saphenous nerve. Likewise, the talar distraction pin could be slightly medial to the tibialis anterior tendon. All measurements are listed in Table 1.

Table 1.

Proximity of Arthroscopic Portals and Distraction Pins to Tendinous and Neurovascular Structures in Cadaveric Foot and Ankle Specimens.

Specimen	Medial Border of Extensor Hallucis Longus Tendon to Neurovascular Bundle (mm) at the Level of the Talonavicular Joint	Medial Border of Tibialis Anterior Tendon to Saphenous Nerve (mm) at the Level of the Talonavicular Joint	Medial Border of Tibialis Anterior Tendon to Navicular Distraction Pin (mm)	Medial Border of Saphenous Nerve to Navicular Distraction Pin (mm)	Medial Border of Tibialis Anterior Tendon to Talar Distraction Pin (mm)	Medial Border of Saphenous Nerve to Talar Distraction Pin (mm)
1	9	6	2	3	4	4
2	8	7	2	4	4	4
3	9	7	3	3	5	3
4	9	7	2	4	5	4
5	10	7	3	4	6	4
Mean	9.0	6.8	2.4	3.6	4.8	3.8

Cases

Patients included a 15-year-old female soccer player (patient 1), a 37-year-old male rock climber (patient 2), and a 43-year-old female semiprofessional runner (patient 3). Patients presented following a period of rest and non-weight-bearing recommended at other institutions. Patient 1 presented with a navicular OCL previously diagnosed by MRI from an outside institution (Figure 4A). The patient described pain, inflammation, and swelling of the left midfoot after athletic activities for several years. Patient 2 presented with ongoing pain in the left midfoot since operative fixation of a navicular fracture–dislocation treated at an outside institution 1 year prior. Preoperative MRI indicated changes in the distal talus and the navicular following the previous operative fixation with a large subchondral cyst in the plantar aspect of the navicular bone. Patient 3 presented with persistent midfoot pain and preoperative MRI indicated a stress reaction in the central portion of the navicular, with a cystic OCL in the dorsocentral aspect of the navicular bone, in addition to plantar fasciitis.

Figure 4.

(A) Preoperative sagittal fast-spin-echo proton density magnetic resonance image of a talonavicular osteochondral lesion. (B) Postoperative sagittal fast-spin-echo proton density magnetic resonance image of the same lesion 3 months following microfracture (B). Signal consistent with reparative fibrocartilage can be seen postoperatively. (C) Postoperative sagittal T2 mapping of a talonavicular osteochondral lesion 3 months following microfracture. T2 mapping stratification demonstrates signal prolongation within the lesion. The osteochondral lesion is demarcated by the circle in each image. All images are from case 1.

Nonoperative modalities of treatment had failed in all patients before operative intervention was considered. The operations consisted of microfracture of a navicular OCL, with curettage of subchondral cystic lining if present, removal of loose bodies from the talonavicular joint, debridement of the joint, and resection of scar tissue (Figure 3). A symptomatic 4.5 mm screw was removed in patient 2 and a 3.5 mm titanium screw was placed across the stress reaction seen in patient 3.

FAOS and SF-12 scores for all patients are listed in Table 2. MRI and T2 mapping at 3 months postoperatively revealed signal consistent with fibrocartilaginous tissue in the area of the navicular OCL and marrow edema in the talar head attributed to postoperative changes resulting from placement of the distraction pin in all patients (Figure 4). In patients 1 and 3, MRI at approximately 1 year postoperatively indicated stable fibrocartilage and continually resolving edema in the talar head. In patient 2, 1-year postoperative MRI and indicated mild degeneration of the navicular articulation with the medial and intermediate cuneiform joints as well as mild talonavicular degeneration. MRI obtained 16 months postoperatively indicated stable fibrocartilage in the area of the OCL and that midfoot degeneration had ceased progression.

Table 2.

Foot and Ankle Outcome Scores (FAOS) and Short Form–12 General Health Questionnaire (SF-12) Scores at Pre- and Postoperative Time Points.

Patient	Preoperative FAOS	Postoperative FAOS	Preoperative SF-12	Postoperative SF-12
1	80.6	100.0	43.4	55.6
2	41.7	70.0	18.5	49.6
3	77.8	94.4	38.1	60.8
Mean	66.7	88.1	33.3	55.3

Regarding return to activity, patient 1 had no pain, was gradually increasing weight-bearing, and began physical therapy 6 weeks after operation. Six weeks postoperatively she was experiencing tethering of the EHL due to development of scar tissue which resolved with physical therapy. The patient was able to gradually return to her athletic activities 3 months after the operation and had no complaints of pain at 6 months. She has subsequently accepted a college soccer scholarship. Twenty months following operation the patient continued to remain pain free and maintained full participation in soccer. Patient 2 was experiencing dull pain in the dorsal aspect of the midfoot at 3 months, but had returned to full weight-bearing with normal range of motion, and began to increase physical activity. At 6 months postoperatively the dull pain resolved and the patient returned to rock climbing. The patient experienced occasional pain along the tibialis posterior tendon unrelated to the index injury and maintained full participation in rock climbing 16 months postoperatively. Patient 3 began full weight-bearing 8 weeks after operation. The patient was asymptomatic and began gradual return to running activities after 3 months. Running was continued with no complaints of pain 16 months following operation. Minor scar formation in the anterior recess of the ankle joint was resolved through physical therapy and the patient was continuing activity 22 months following the operation.

Discussion

Cadaveric study indicated that arthroscopy of the talonavicular joint can be performed without insult to important tendinous and neurovascular structures. This approach provided minimally invasive, adequate access for curettage, synovectomy, loose body removal, and OCL microfracture. In a small number of patients with short to midterm follow-up, talonavicular arthroscopy resulted in improved FAOS and SF-12 scores as well as return to activity.

In the talonavicular joint, there is scant literature on the use of arthroscopy and no studies describing the use of arthroscopy specifically for the treatment of talonavicular OCLs to the author’s knowledge. Most previously described operative techniques for debridement of the talonavicular joint involve an open approach through a single dorsomedial incision.^1,3,11,15 Successful treatment of OCLs with external arthrodiastasis and microfracture in 3 patients has also been recently reported.¹³ Complications from open procedures include delayed soft tissue healing, nerve injury, vascular injury, and wound complications. Several studies have shown that arthroscopy is an effective tool to gain access to both the talar and navicular articular surfaces, with up to 83.2% of the talus and 98.6% of the navicular surfaces accessible for debridement.^4-6,8 Based on the current literature, talonavicular arthroscopy has only been reported in 2 patients. One report described arthroscopy of the joint for diagnosis of a navicular fracture but was then converted to an open procedure.^5,8 The other reported case of talonavicular arthroscopy was for the purpose of triple arthrodesis.⁵

Talonavicular arthroscopy was first described along with preliminary results of 7 cases of calcaneocuboid or talonavicular joint pathology.⁸ Arthroscopic portals included a medial portal located medial to the saphenous nerve, a central portal located between the tibialis anterior tendon and the saphenous nerve, and a lateral portal located between the tibialis anterior tendon and the EHL. However, only 1 of these 7 patients was treated for talonavicular pathology. Though this patient was initially diagnosed with osteochondritis dissecans (OCD) preoperatively, arthroscopy established that an avulsion fracture was present necessitating an arthrotomy and bone grafting. The authors did not report any other cases involving the talonavicular joint, but did provide a list of indications for arthroscopy of the midfoot, including OCD and OCLs, loose bodies, noninflammatory synovitis, inflammatory synovitis, osteophytes, synovial impingement, infection, staging, biopsy, and diagnosis.⁸

A subsequent report described the use of a dorsolateral portal located lateral to the deep peroneal nerve, a dorsomedial portal located between the tibialis anterior tendon and EHL, and a medial portal located medial to the tibialis anterior tendon to gain access to the talonavicular joint for an arthroscopic approach to triple arthrodesis.⁵ The safety and efficacy of this technique was studied in 9 cadavers by arthroscopically abrading the articular cartilage of both the talar and navicular surfaces and quantifying the percentage of total surface area that could be accessed.⁶ This study found that all but the small dorsal corners of either surface and the vertex of the talar head were accessible. The safety of talonavicular arthroscopy was calculated by measuring proximity of portals to tendons and neurovascular structures. Although the approach was deemed effective, it was found that the dorsomedial portal was 1 mm lateral to the intermediate cutaneous branch of the superficial peroneal nerve and the nerve was in direct contact with the needle demarcating the portal in 2 specimens.⁶ An additional cadaveric study described a similar technique for the purposes of arthrodesis.⁴ Eight cadavers underwent arthroscopic debridement via a dorsomedial instrumentation portal located medial to the tibialis anterior tendon and via a dorsolateral visualization portal located lateral to the lateral terminal branch of the deep peroneal nerve. While mean debridement area was 83.2% in the talus and 98.6% in the navicular, the dorsolateral portal was a median distance of only 1 mm from the lateral branch of the deep peroneal nerve.

Using the approach described in the current study, which utilized a combination of arthroscopy portals differing from those previously described in cadaveric studies, the dorsal arthroscopic portal was nearly 1 centimeter from the neurovascular bundle and the medial arthroscopic portal was located over half a centimeter from the saphenous nerve. Because the neurovascular bundle was located lateral to the EHL in all specimens, the EHL can be used as a landmark to avoid the neurovascular bundle when creating the dorsal portal. In addition, placing the medial portal just medial to the tibialis anterior tendon should avoid proximity to the saphenous nerve. Using this approach, surgeons can expect to preserve important anatomic structures and gain adequate joint access for debridement and microfracture of the talonavicular joint. Limitations of this approach include the need for distraction which places strain on the soft tissue envelope. However, this did not appear to be detrimental in the 3 cases reported in the current study.

We presented 3 cases of arthroscopic microfracture in the talonavicular joint and their clinical and MRI outcomes. In all 3 patients we were able to successfully identify, access, debride, and microfracture the OCL. All patients were able to begin gradual return to athletic activities within 12 weeks and maintained previous levels of athletic activity at latest follow-up. Patient 1 experienced tethering of the EHL due to development of scar tissue. However, scar tissue was also present near the dorsal aspect of the joint at the time of operation, possibly related to the patient’s soccer activities, and was resected. Postoperative EHL tethering was resolved with simple physical therapy and did not hinder return to sport. Patient 2 had postoperative dysesthesia, but this pain later resolved and may have been related to debridement of scar tissue from the index procedure performed at the time of talonavicular arthroscopy. Patient 2 also described dull ache in the dorsal midfoot but had normal range of motion and was able to return to full weight-bearing and activities. It is important to note, however, that patient 2 also had symptomatic hardware from a prior navicular fracture–dislocation. We were successfully able to perform arthroscopic microfracture for all OCLs and MRI indicated signal consistent with presence of reparative fibrocartilaginous tissue in all patients (Figure 4).

In light of previous studies and the results of the present study, we recommend arthroscopy for debridement and microfracture of talonavicular OCLs as arthroscopy is minimally invasive and is associated with decreased pain, earlier return to activity, and decreased health care expenditures.^8,14 Depending on portal placement, surgeons must be aware of proximity to neurovascular structures.

There were several limitations to the current study. The cadaveric portion of the study may not exactly recreate the physiology of patients. In addition, this study included a small number of patients and retrospective design. One patient had removal of retained hardware at the time of operation and another had a 3.5 mm screw placed across a stress reaction. This may have influenced outcomes. Further research with larger cohorts and long term follow-up is required to determine if arthroscopic treatment of talonavicular joint and the midfoot is favorable over open approaches.

Conclusions

Talonavicular arthroscopy allowed visualization, curettage, synovectomy, loose body removal, and microfracture of OCLs that would have otherwise required an open approach. At early follow-up, all patients had returned to their previous activity levels. Arthroscopy of the talonavicular joint was a viable approach for microfracture of OCLs to stimulate fibrocartilaginous infill. Limited soft tissue dissection, the potential for few wound complications, and the ability to visualize the entire joint made this an attractive alternative for treating OCLs of the talonavicular joint.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received the following financial support for the research, authorship, and/or publication of this article: Author John G. Kennedy is a consultant for and receives research funding from Arteriocyte, Inc. He is also a board member of ESSKA-AFAS and a Chairman of the International Congress on Cartilage Repair of the Ankle (ICCRA). However, these disclosures are unrelated to the current study.

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