Using a Direct Lateral Incision as an Instrumentation Portal During Ankle Arthroscopy: A Retrospective Cohort Comparison of Complications

Abstract

Background:

Ankle arthroscopy (AA) is a commonly used operative technique to diagnose and treat a variety of intraarticular pathologies of the ankle joint. In AA, 2 portals are commonly established to achieve visualization of the joint: the anteromedial (AM) and anterolateral (AL) portals. However, the superficial peroneal nerve (SPN) runs near the anterolateral portal site; thus, creation of the AL portal is associated with neuropraxic injuries to the SPN.

When AA is combined with additional procedures, such as a Brostrom-Gould ligament repair or open reduction internal fixation (ORIF), the use of a direct lateral incision is required. We present a novel approach to combining AA with lateral adjunct procedures which avoids creation of the AL portal; the AM portal and lateral incision are used for instrumentation instead. The primary objective of this study is to compare complication rates, such as SPN injury, between the lateral incision (LI) approach and conventional arthroscopy plus a lateral incision approach.

Methods:

Following IRB approval, a retrospective chart review was conducted spanning a time frame from January 2020 to October 2024. Patients were included if they underwent AA plus either a Brostrom-Gould repair or ORIF (AA+) or if they underwent AA plus adjunct procedures using the lateral portal instrumentation method (LI). Ninety-four patients were initially identified; 2 were excluded per criteria. Demographic information, intraoperative details, and any postoperative complications or reoperations were recorded. Descriptive statistics were used to describe demographics and operative data, and 2-tailed Student t tests were used to identify statistical differences between group metrics.

Results:

Ninety-two patients were included in the study. No statistical differences were observed between cohorts in either of the intraoperative metrics considered (procedural duration and tourniquet duration; P = .44 and .89, respectively). In addition, complication and reoperation rates were not statistically different between the LI and AA+ groups (P = .94 and .40, respectively). The rate of SPN neuropathy or neurapraxia were also compared between groups, resulting in no statistical differences (P = .37).

Conclusion:

In this retrospective cohort study, we observed no differences when only anteromedial and lateral portals are used for an ankle arthroscopy with adjunct procedures compared with the traditional 3-incision approach. We hypothesize that instances of infection or wound dehiscence would decrease given a large enough cohort because of the creation of 1 fewer portal. However, given the small, underpowered sample, we cannot determine whether the lateral approach alters complication risk; larger multicenter studies are needed.

Level of Evidence:

Level III, retrospective cohort study.

Introduction

Ankle arthroscopy provides a minimally invasive option for direct visualization of intraarticular pathologies and is commonly used for the diagnosis and treatment of various ankle pathologies including chronic ankle instability and acute trauma.^17,21 The current gold standard treatment for lateral ankle instability is surgical repair of lateral ankle ligaments using a Brostrom-Gould technique. This can be performed either open or arthroscopically, although there is evidence showing better clinical outcomes using an arthroscope. ²² Additionally, ankle arthroscopy can be employed for the diagnosis and treatment of acute ankle trauma, including fractures. The goal of treating unstable ankle fractures is stable, anatomic restoration of the joint, which is most often achieved through open reduction internal fixation (ORIF). The adjunctive use of ankle arthroscopy with ORIF has been previously described.^3,12,15,19 Benefits include direct visualization of intraarticular lesions, direct visualization of the reduction, and avoidance of ankle arthrotomy for preservation of soft tissue stabilization. ³

Arthroscopic surgery can be performed in both the anterior and posterior ankle. Typically, anterior ankle arthroscopy is carried out by creating 2 portals: an anteromedial (AM) and anterolateral (AL) one. The AM portal is established with an incision slightly medial to the tibialis anterior tendon at the level of the ankle joint. With the patient’s foot held in full dorsiflexion, the arthroscopic instrument is then introduced while aiming toward the tip of the lateral malleolus. ¹⁷ The AL portal is commonly established by creating an incision lateral to the peroneus tertius tendon and proximal to the ankle joint. However, to avoid the neurovascular structures and tendons located nearby, an “inside-out” transillumination technique is employed. The arthroscope introduced anteromedially is brought to the site of the AL incision and is used to transilluminate superficial structures, such as the superficial peroneal nerve (SPN), from the inside-out. There are also proponents of preoperatively marking the location of the SPN as it is shown to decrease the risk of SPN injury. This may be performed by palpating the SPN with the foot in adduction and plantar flexion, then marking it with a sterile pen.^11,18 Establishment of an anterocentral portal has also been discussed but is discouraged in practice because of a risk of iatrogenic neurovascular injury. ¹⁰

The SPN supplies sensation to the anterolateral leg and to the dorsum of the foot. The SPN divides into the intermediate and medial dorsal cutaneous branches as it penetrates the crural fascia approximately 6.5 cm proximal to the tip of the fibula.^1,17 Their superficial location near the AL portal site make injury to the SPN one of the most common complications of anterior ankle arthroscopy.^5,7,8 Injury to the SPN and its branches often presents as pain, numbness, or paresthesias in the SPN sensory distribution areas. The AL portal is often implicated in SPN injuries; thus, great care must be taken during establishment of this portal to avoid the nerve.^5,14 Multiple studies have shown SPN injury rate ranging from 1.04% to 8.3% after anterior ankle arthroscopy.^2,18,24

Oftentimes, ankle arthroscopy is performed in tandem with reconstructive procedures such as ORIF of ankle fractures or ligament repair rather than in isolation. We posit that usage of this lateral incision for fracture or ligament repair instead of the AL portal incision decreases the risk of complications, such as SPN injury. Establishing an AL portal is the most common culprit for postoperative SPN neurapraxia; therefore, by avoiding this incision there is a decreased risk of injury. As a corollary, if case complexity can be decreased, the risk of complications should decrease as well. Thus, we hypothesize that instrumenting through only the lateral and AM portals using this technique will reduce the risk of complications, specifically SPN neuropraxic injuries, compared with traditional AM and AL portals plus a lateral incision for adjunct procedures.

Materials and Methods

Following IRB approval, a retrospective review of electronic medical records was performed of all ankle arthroscopy procedures completed by a single surgeon at a single institution between January 2020 and October 2024. Inclusion criteria for this study included patients who underwent ankle arthroscopy within the time frame. Exclusion criteria included patients who did not undergo the stated procedure within the time frame and patients whose operative indication included SPN neurolysis as this was one of the study variables under analysis.

Following initial review, 94 patients were identified of which 2 were excluded as they did not meet inclusion criteria (eg, did not undergo ankle arthroscopy), resulting in 92 patients for analysis. Patients were then assigned to either of 2 groups: ankle arthroscopy using anteromedial and lateral portals (LI group) or ankle arthroscopy plus adjunct procedure using AM and AL portals plus a lateral incision (AA+ group). Patients in the LI group underwent an additional procedure, such as ORIF of the fibula, that used a direct lateral incision. The direct lateral incision was then used as the lateral portal site for ankle arthroscopy instead of the traditional anterolateral portal. Patients in the AA+ group underwent ankle arthroscopy plus an adjunct procedure including Brostrom-Gould ligament repair or ORIF.

Demographic information including age, gender, operative diagnosis/indication(s), and operative details including date, primary surgeon, procedure(s) performed, procedure duration, and duration of active tourniquet use were obtained. Postoperative complications, reoperation details, and follow-up duration were identified in subsequent postoperative visits and progress notes. The primary study outcome was to compare SPN complication rates between the study groups. Secondary outcomes include comparison of complication and reoperation rates.

Surgical Technique

The creation of the far lateral portal described in this series occurs in the setting of other longitudinal lateral incisions used for lateral ligament repair surgery or fibula fracture repair surgery. Prior to any arthroscopy, the lateral incision and dissection is begun with care not to enter or perforate the ankle joint capsule laterally. Full-thickness flaps are elevated with care taken to protect branches of the SPN if they are present (Figure 1). This exposure is the same in principle for fibula fracture fixation as well as lateral ligament repair; the periosteal sleeve of the fibula is used as a depth marker for the lateral ankle capsule, and flaps are developed using this as a marker. For lateral ankle ligament repairs, the dissection is extended distally to view the inferior extensor retinaculum for Gould modifications as necessary. For fibula fractures, the exposure identifies the distal tip of the fibula but otherwise does not extend further distally. Once these flaps have been identified, the anatomy is easy to view before fluid insufflation of the ankle and the extensor retinacula can be marked as necessary for a Gould modification. With the lateral incision created, the surgeon can proceed with arthroscopy to use the lateral surgical wound as the lateral portal to attempt to minimize injury to the SPN branches from the anterolateral portal. The senior author’s practice is to use a noninvasive ankle joint distractor and complete this dissection before suspension of the limb using the distractor to minimize ankle distractor time, especially with surgical resident trainees present as it has been shown to correlate with postoperative complication risk.^9,23 A typical anteromedial portal location is identified and created with percutaneous incision, blunt dissection and perforation into the ankle joint capsule, and insertion of arthroscope (Figure 2). When instrumentation is required from the lateral incision for dissection, cautery devices, probe, etc, the arthroscope is used to view laterally and a blunt hemostat is used on the anterolateral ankle joint capsule to distend the joint and then perforate the capsule bluntly so it may be viewed with the arthroscope (Figure 3). The instruments for dissection or cautery are then introduced through this portal from within the lateral incision reducing surgical trauma, and the arthroscopic procedures are completed in this manner prior to removal of the distractor and completion of the open portions of the surgical procedure (Figure 4).

Figure 1.

Establishment of the lateral portal. The lateral portal is marked prior to incision with a hockey-stick-shaped trace over the lateral malleolus (left). Following application of noninvasive ankle distraction, full-thickness flaps are elevated, being careful to protect any branches of the SPN in close proximity (right).

Figure 2.

Establishment of the anteromedial portal. The anteromedial portal location is identified and created with a percutaneous incision. Blunt dissection and perforation is then carried down into the ankle joint capsule.

Figure 3.

Insertion of arthroscope and connection of portals. The arthroscope is inserted into the anteromedial portal. A blunt hemostat is used on the anterolateral ankle joint under arthroscopic visualization to perforate the anterolateral ankle joint capsule.

Figure 4.

Arthroscopy through anteromedial and lateral portals. Arthroscopy is then carried out using both anteromedial and lateral portals. Both arthroscope and shaver are inserted into the joint space, as evidenced by the on-screen footage visible in the figure.

Statistical Analysis

Descriptive statistics were performed including mean values for continuous variables and percentages for discrete and binomial variables. Between-groups parameters were assessed using a 2-tailed Student t test for continuous variables such as procedure duration (minutes), and a χ² test was performed for categorical variables such as complication rate (yes/no). A priori analysis indicated that if the incidence of neuropraxic injuries reduced from 8.5% to 1% by instrumenting through the lateral portal instead of the AL, 250 patients in each group would be required for adequate study power. Statistical significance for all tests was set at α = 0.05. BlueSky Statistics, version 10.3.4, software was used for analyses.

Results

Ninety-two patients were included in this study, of which 35 underwent LI and 57 underwent AA+ (Figure 5). The mean age was 42 years (range, 19-78) for LI patients and 39 years (range, 13-72) for AA+ patients. The mean procedure duration was 102 minutes (range, 53-171) for LI and 107 minutes (range, 55-246) for AA+ patients. Mean follow-up length for all patients in this study was 14.2 months (range, 0.49-246). There were no statistically significant differences in demographic data between both groups (Table 1).

Figure 5.

Exclusion flowchart. Pictorial depiction of the identification and exclusion process.

Table 1.

Comparison of Intraoperative Data for AA+ vs LI groups.

	AA+ Group Ankle Arthroscopy + ORIF and/or Brostrom-Gould Repair, Mean ± SD (Range) or n (%) (n = 57)	LI Group: Lateral Portal Ankle Arthroscopy, Mean ± SD (Range) or n (%) (n = 35)	P Value Between Groups a
Age, y	38.53 ± 17.06 (13-72)	42.46 ± 16.35 (19-78)	.274
Procedure duration (min)	107.47 ± 34.27 (55-246)	102.37 ± 28.22 (53-171)	.441
Tourniquet duration (min)	85.63 ± 24.90 (29-124)	86.41 ± 23.57 (39-133)	.884
Follow-up length (mo)	18.94 ± 32.21 (1.28-246)	6.44 ± 6.90 (0.49-35)	.012
Complications	20 (35.09)	12 (34.29)	.938
Reoperation	8 (14.03)	8 (22.86)	.307

^aBoldface indicates statistical significance.

Overall, complication rates demonstrated no statistical differences between study groups. We observed 20 complications in the AA+ group (20/57, 35.09%) and 12 in the LI group (12/35, 34.29%) (P = .938). The most common postoperative complication was symptomatic hardware, occurring in 6 AA+ patients (6/57, 10.53%) and 5 LI patients (5/35, 14.29%). SPN neuropathy occurred in 2 patients (5.71%) in the LI group and 1 patient in the AA+ group (1.8%) (Table 2). One instance of SPN neuropathy in the LI group resolved at follow-up; the other did not and required hardware removal and SPN neurolysis for resolution of symptoms. The singular instance of SPN neurolysis in the AA+ group did not resolve at follow-up, and the patient has sought nonoperative management of their symptoms. Less common complications included wound dehiscence, plantar foot numbness, and weakness (all in the same patient).

Table 2.

Comparison of complication data for AA+ vs LI groups.

	Ankle Arthroscopy + ORIF and/or Brostrom-Gould Repair (AA+), n (%)	Lateral Portal Ankle Arthroscopy (LI), n (%)
Symptomatic hardware	6 (10.5)	5 (14.29)
Pain	12 (21.1)	2 (5.71)
Superficial peroneal nerve neuropathy	1 (1.8)	2 (5.71)
Other a	1 (1.8)	3 (8.57)

Abbreviation: ORIF, open reduction internal fixation.

^aOther complications in hard-style arthroscopy included wound dehiscence (1), symptomatic distal tibia exostosis (1), and plantar foot numbness (1). Other complications in standard arthroscopy + ORIF and/or Brostrom-Gould repair included weakness (1).

In addition, there were no statistically significant differences in reoperation rates between study groups (Table 3). We observed a 31.4% reoperation rate in the LI group (11/35) and 14.1% reoperation rate in the AA+ group (8/57) (P = .40). Hardware removal was the most common reoperation in both groups (8.8% and 20%, respectively), consistent with symptomatic hardware being the most common complication.

Table 3.

Comparison of hardware removal rates AA+ vs LI groups.

	Ankle Arthroscopy + ORIF and/or Brostrom-Gould Repair (AA+), n (%)	Lateral Portal Ankle Arthroscopy (LI), n (%)
Hardware removal	5 (8.8)	7 (20)
Other a	3 (5.26)	4 (11.43)

Abbreviation: ORIF, open reduction internal fixation.

^aOther complications for the AA+ group included lateral ankle stabilization with tendon allograft (1), subtalar debridement & loose body removal (1), and total ankle arthroplasty (1). Other complications for the LI group included irrigation & debridement (1), distal tibia exostectomy (1), SPN neurolysis (1), and ankle arthroscopy with extensive debridement (1)

Within the AA+ group, 56% (32/57) patients underwent Brostrom-Gould ligament repair and 44% (25/57) underwent ORIF. There were no significant differences in complication rates (P = .90) or reoperation rates (P = .71) between patients who underwent Brostrom-Gould ligament repair compared to those who underwent ORIF within the AA+ group. Within the LI group, 66% (23/35) patients underwent Brostrom-Gould ligament repair, and 34% (12/35) underwent ORIF. There were no significant differences in complication rates (P = .93) or reoperation rates (p = .14) between patients who underwent Brostrom-Gould ligament repair compared with those who underwent ORIF within the LI group.

Discussion

This study demonstrates that use of a direct lateral incision as a lateral portal site, instead of the classic anterolateral portal, during ankle arthroscopy results in no significant difference in complication or reoperation rates, specifically the rate of SPN neuropathy. Because the study was underpowered, the absence of statistical significance should not be interpreted as equivalence.

There is a wealth of evidence demonstrating that SPN neuropathy is the most common complication that patients experience after ankle arthroscopy, with reported rates ranging from 1.04% to 8.3%.^{2,4,6,18,20,23-25} In a retrospective review of 294 ankle arthroscopy cases by Young and Flanigan, they reported that 16 of the 20 complications recorded were neurologic in nature, and 6 of them were specifically related to the anterolateral portal. ²³ Another study by Amendola et al ² demonstrated that 3 of 79 patients experienced neurologic complications, with 1 patient specifically stating SPN irritation at the anterolateral portal site. We found SPN injury to occur in 3 patients (3/92, 3.26%), with long-term complications occurring in one patient (1/92, 1.09%), which is consistent with results previously published in the literature.

A cadaveric study by Ögüt et al provides anatomic evidence for the high incidence of SPN neuropathy following AA. They determined that the greatest risk of SPN injury occurred within a zone ranging from 0 to 3 mm lateral of the peroneus tertius (PT) tendon. After analysis of the data, the authors of this study recommended that the anterolateral portal should be established a minimum of 4 mm lateral to the PT tendon to avoid injury to the SPN. They described a high risk of SPN injury within a zone ranging from 0 to 3 mm lateral to the tendon. ¹⁶ Thus, we hypothesized a decreased risk of SPN neurapraxia and overall complications by using a lateral portal farther from the SPN instead of creating an anterolateral portal. We were unable to confirm this hypothesis but demonstrated that no further risk is introduced through utilization of a far lateral portal site. Future studies containing a larger sample size are warranted to clarify any significant difference between both procedures.

Understandably, there may be concern that foregoing establishment of the anterolateral portal in favor of the lateral incision may result in limited visualization of key anatomic structures. There is a potential compromise that is made with this technique; access to structures in the posterior lateral aspect of the joint could be limited when using the lateral incision. The anterolateral portal typically is established directly over the lateral gutter and would likely allow for better access to that portion of the joint. Future work should investigate precisely which structures can and cannot be accessed using either method.

Adequate visualization during an arthroscopic procedure is largely dependent on fluid management. Adequate inflow of fluid into the ankle joint allows for proper joint distention and bleeding control. However, pumping significant amounts of fluid into a small joint space, such as the ankle, increases the amount of fluid extravasated into surrounding tissues and theoretically increases the risk of complications such as compartment syndrome. Although rare, the development of compartment syndrome after ankle arthroscopy has been reported.^4,13 Fluid extravasation can also increase the difficulty of lengthy arthroscopic procedures because of significant tissue swelling as the procedure progresses. A hypothesized benefit to performing ankle arthroscopy through a lateral portal is that anatomical layers are easier to visualize and dissect compared to a classical anterolateral approach. Thus, a lateral arthroscopic approach to the ankle joint may decrease the amount of fluid extravasation, and possibly reduce the risk of complications such as compartment syndrome. Additionally, the option for a classical anterolateral approach remains if needed.

This study is not without limitations. As this is the first study to assess the effectiveness of a lateral portal in ankle arthroscopy compared to the classic anterolateral portal, there exists a paucity of historical data to corroborate our results. This study is limited by its single-surgeon, single-institution design, small sample (power ≈55%), lack of patient-reported outcomes, and incomplete intraarticular pathology data. Follow-up was short for many patients (minimum 0.5 months), which may miss later complications. We performed only crude comparisons; residual confounding by procedure type and demographics likely remains.

Conclusion

To our knowledge, no studies published to date investigate the possibility of performing anterior ankle arthroscopy via a portal other than the classically established anteromedial and anterolateral portals. The findings from this observational study suggest that in patients undergoing adjunctive procedures requiring a direct lateral incision to be made, such as ORIF, ankle arthroscopy can be carried out effectively through the lateral incision, eliminating the need for an additional incision to establish the anterolateral portal. In this retrospective cohort, using the lateral incision for instrumentation appears feasible; however, definitive comparisons of complication risk require larger, adequately powered, multicenter studies.

Supplementary Table 1.

Chi-Square Test Analysis of Adjunctive Procedures Within Groups.

Group	Brostrom-Gould Ligament Repair	ORIF	P Value
AA+	n (%)
Complication(s)	11 / 32 (34)	9 / 25 (36)	.90
Reoperation(s)	4 / 32 (13)	4 / 25 (16)	.71
LI
Complication(s)	8 / 23 (35)	4 / 12 (33)	.93
Reoperation(s)	7 / 23 (30)	1 / 12 (8)	.14

Abbreviations: AA+, ankle arthroplasty plus either a Brostrom-Gould repair or ORIF; LI, ankle arthroplasty plus adjunct procedures using the lateral portal instrumentation method; ORIF, open reduction internal fixation.