Abstract
Background:
Isolated gastrocnemius contracture (IGC) is associated with various foot and ankle pathologies. To address the problem of IGC, a number of gastrocnemius lengthening procedures have been described. Although proximal medial gastrocnemius recession (PMGR) has shown to be an effective operative treatment for IGC, it poses risks to various anatomic structures around the knee joint and requires the patient to be positioned prone. As an alternative, we proposed to release the medial gastrocnemius at the division between the proximal one-third and distal two-thirds of the gastrocnemius muscle to correct equinus contracture, while minimizing risk to other structures. The aim of this study was to describe an anatomic basis for a medial gastrocnemius recession (MGR) and to investigate the anatomic structures at risk in comparison to PMGR.
Methods:
Eight cadaveric lower leg specimens were used in the study. The standard PMGR and the novel MGR were performed on each specimen. After completion of the 2 procedures, complete dissection was performed to investigate the distances between surgically released fascia margins and surrounding anatomic structures, including the greater saphenous vein, small saphenous vein, saphenous nerve, medial sural cutaneous nerve, semimembranosus tendon, tibial nerve, and popliteal artery. The mean distances were calculated and the shortest distances for each structure were reported.
Results:
Proximities of anatomic structures to surgically released gastrocnemius fascia at the medial and lateral margins were notably different between the 2 techniques. For the PMGR, the semimembranosus tendon (95% confidence interval of 2.4-7.4 mm), small saphenous vein (3.4-10.0 mm), popliteal artery (3.9-9.3 mm), and tibial nerve (5.0-11.1 mm) were in greater proximity to the operative margin. For the MGR, the greater saphenous vein (5.3-17.6 mm) and saphenous nerve (5.1-18.6 mm) were at greater risk.
Conclusions:
MGR at the proximal one-third of the gastrocnemius muscle may be a safe alternative for operative treatment of IGC.
Clinical Relevance:
We identified the major structures at risk when performing the proximal medial gastrocnemius release and propose a novel, possibly safer alternative for the medial gastrocnemius release.
Keywords
Introduction
Isolated gastrocnemius contracture (IGC) has been implicated as the primary or a contributing factor in a variety of different foot and ankle pathologic conditions. 6 Treatment of foot and ankle mechanical disease processes in which IGC may be a contributing mechanism must address this component of the disease in order to improve gait mechanics, pain, and function. Different operative approaches have been developed to address heel cord tightness secondary to IGC.
The distal gastrocnemius recession (Strayer procedure), Baumann procedure, and proximal medial gastrocnemius release (PMGR) are methods used to treat IGC. The Strayer is performed by making a single transverse division of the distal gastrocnemius aponeurosis after isolating it from the underlying soleus and suturing the released and retracted tendon to the soleus fascia. The Baumann intramuscular gastrocnemius lengthening releases the anterior aponeurosis of the medial and lateral gastrocnemius more proximally. 10 This procedure is a slightly more invasive procedure designed to allow for the option to release of the entire gastrocnemius-soleus complex with an added release of the soleus fascia.4,14
The PMGR releases only the medial gastrocnemius head, as a possibly safer alternative to complete recession.2,10 Though reports of complications are scarce, many orthopaedic surgeons have reservations regarding regular use of an approach in close proximity to the popliteal fossa because of the risk of neurovascular injury. We propose a novel medial gastrocnemius release (MGR) technique as a variant of the PMGR in an anatomic location that could pose less risk to neurovascular structures. This technique provides a release of the posterior aponeurosis of the medial gastrocnemius similar to the PMGR, but in a more distal anatomic location, differing from the Baumann release of the deeper anterior gastrocnemius aponeurosis, leading to a potentially different biomechanical effect.
The purpose of our study was to identify the various anatomic structures at risk and quantify the proximity of these to the operative field. We proposed a cadaveric model for an anatomic evaluation of the standard PMGR approach, as described by Barouk 2 , followed by our novel MGR at the junction of the proximal one-third and distal two-thirds of the gastrocnemius muscle belly.
Methods
A total of 8 cadaveric lower extremity specimens were placed in the prone position. On each specimen, a standard PMGR and the novel MGR were performed. PMGR as described by Barouk 2 was completed with a 2- to 3-cm transverse incision 1 cm inferior to the popliteal flexion crease, and 1 cm lateral to the medial fovea. Dissection was carried through subcutaneous fat to the posterior crural fascia of the leg. The medial head of the gastrocnemius was identified after incision in the deep fascia, and the tendinous portion of the aponeurosis was located medially. The tendinous fibers of the proximal medial gastrocnemius were completely resected. The MGR was then performed on each specimen in the prone position. We identified the medial border of the popliteal crease and the gastrocnemius musculotendinous junction. Using a tape ruler, we measured the length between the 2 points, which represents the length of the medial gastrocnemius muscle belly. Using this measurement, we delineated the division between the proximal one-third and distal two-thirds of the gastrocnemius muscle belly. For most specimens, this was 6-7 cm distal to the popliteal crease. A 2-cm transverse skin incision was made at the mark, and soft tissue dissection was performed. The posterior fascia was incised in line with the skin incision and the gastrocnemius fascia was exposed. Providing medial traction on the medial border of the gastrocnemius fascia with Allis clamps, a transverse incision was made through the fascia directed medial to lateral using a no. 15 blade (Figure 1).
The standard PMGR was performed 1 cm inferior to the popliteal crease and 1 cm lateral to the medial fossa. The MGR was performed at the division between the proximal one-third and distal two-thirds of the medial gastrocnemius muscle belly. MGR, medial gastrocnemius release; PMGR, proximal MGR.
After each release had been performed, the posterior leg was dissected and adjacent important anatomic structures were identified. The distance from the closest aspect of the operative field in each approach to these structures was measured, to the nearest one hundredth of a millimeter utilizing point calipers, and recorded in each specimen. The particular structures included in this study were the saphenous vein, the small saphenous vein, the medial sural cutaneous nerve, the tibial nerve, the popliteal artery, and the semitendinosus tendon. If the structures were located in a different compartment (ie, anterior) or deeply embedded and not visible from the operative field at the level of release, they were deemed too distant to be considered at risk for the particular procedure and not measured. Measurements were recorded for each specimen and mean distances calculated for each structure in the 2 separate approaches.
Results
Mean proximities of the structures to the medial or lateral margins of fascial releases were calculated from all cadaver specimens. The mean distances from the operative margin, 95% confidence intervals, and minimum and maximum sample distances for both releases are listed in Tables 1 and 2. The small saphenous vein, semimembranosus tendon, and popliteal artery were the closest structures to the PMGR operative margin, with average distances less than 7 mm away from the resection margin. The greater saphenous vein and saphenous nerve were the farthest from the PMGR site (Figure 2). Standard deviation in the measurement averages showed that the popliteal artery (±3.9 mm) and the semimembranosus tendon (±3.5 mm) had the least variability in proximity between specimens, while structures such as the medial sural cutaneous nerve displayed a wider variety of relative anatomic locations. The popliteal artery was one of the closest structures to the operative field (mean 6.6 mm, with a standard deviation of 3.9 mm), which is of particular importance given the consequences and morbidity of an iatrogenic injury to this structure.
Measurements for Proximal Medial Gastrocnemius Recession. a
Abbreviations: SD, standard deviation; PMGR, proximal medial gastrocnemius recession.
Demonstrates the mean distances measured from the PMGR operative margin after gross dissection of specimens.
Measurements for Medial Gastrocnemius Recession. a
Abbreviations: SD, standard deviation; MGR, medial gastrocnemius recession.
Demonstrates the mean distances, SDs, and confidence intervals for proximities of important structures to the MGR operative margin. Distances of the semimembranosus and semitendinosus tendons as well as the tibial nerve and popliteal artery were not reported/measured in the MGR model as their proximities were felt to be too distant from the operative margin, or were located deep in the soleus muscle belly at this level.
The small saphenous vein (diamond), semimembranosus and semitendinosus tendons (arrow head) were located next to the medial margin of the PMGR (arrow). The greater saphenous vein and saphenous nerve (triangle) were lying in close proximity to the MGR (asterisk) site. MGR, medial gastrocnemius release; PMGR, proximal MGR.
The popliteal artery and tibial nerve were located relatively superficial and lateral to the proximal medial gastrocnemius muscle (Figure 3). The proximities of the semimembranosus, semitendinosus, tibial nerve, and popliteal artery to the MGR field were not recorded, as they were located within a separate anatomic compartment at the level of this release and did not allow for consistent 3-dimensional measurements. Therefore, the operative risk of injury was felt to be negligible. The greater saphenous vein and saphenous nerve were in close proximity to the MGR medial margin. The standard deviations for the means of these structures were higher than those calculated for the PMGR technique, indicating a greater variability in location.
(A) The popliteal artery (indicated by the probe) was in close proximity to the lateral margin of the PMGR (arrow), whereas it was deeply embedded at the level of the MGR (asterisk). The semimembranosus tendon (arrow head) was noted adjacent to the medial margin of the PMGR. (B) The tibial nerve (triangle) was found adjacent to the lateral margin of the PMGR (arrow). MGR, medial gastrocnemius release; PMGR, proximal MGR.
Discussion
Although few clinical complications have been reported with use of the PMGR as described by Barouk 2 , this study demonstrates that certain major structures can be at risk during this procedure. The measurements obtained in this anatomic, cadaveric study confirmed that the semimembranosus tendon and the popliteal artery are both critical structures that are close to the operative field. With an average distance of 4.9 mm and 6.6 mm, respectively, the semimembranosus tendon and popliteal artery are located in close proximity to the release. This is consistent with prior studies suggesting other anatomic risks associated with the procedures.1,8 Hamilton et al performed dissection of the posterior aspect of lower extremity and identified neurovascular structures and measured their distance from the midline of the lower extremity. 9 They found that superficial nerves including the medial and lateral sural cutaneous nerves were located on the lateral aspect of the leg and, therefore, may be at risk when performing a proximal lateral gastrocnemius recession using a posterior approach. The authors found that the tibial nerve was located 3 mm lateral to the midline and the tibial artery and vein consistently located at the midline. Their conclusion was that the approach is safe based on absence of major neurovascular structure in the medial aspect of the proximal leg. However, a direct measurement of adjacent anatomic structures and operative margin of PMGR was not performed. Barouk reports rare and insignificant complications associated with release of only the medial gastrocnemius aponeurosis. 2 Gurdezi et al, in their case series of 16 procedures on 12 patients, report only 1 complication consisting of a deep vein thrombosis. 8 The benefits of this approach are a more cosmetic incision, no postoperative immobilization, earlier return to activity, and preserved muscle strength. Successful applications of PMGR for operative treatments of recalcitrant plantar fasciitis, Achilles tendinopathy, and metatarsalgia have been reported.1,8,11
The Strayer procedure, which is one of the earlier described approaches for specifically addressing IGC, is associated with both stretching and direct injury of the sural nerve, as well as patient concerns regarding cosmesis. 13 Chimera et al reported significantly lower peak isometric strength in 3-month postoperative patients when compared to healthy preoperative controls.3,5 Functional assessment of patients who underwent gastrocnemius recession for Achilles tendinopathy demonstrated significant difficulty with power and endurance activities. 12 As the various approaches to treating IGC are reviewed in the literature, and more follow-up data are obtained, concerns about safety and functional outcomes are surfacing. With these recently described potential disadvantages and complications, the appeal of using alternative techniques for treating IGC is apparent.
We propose a novel technique for addressing IGC. Compared to the PMGR, our MGR approach uses a more distal incision to release the medial gastrocnemius. We believe the optimal site of lengthening is located at the proximal one-third of the medial gastrocnemius muscle belly. This release occurs in the posterior aponeurosis, instead of the anterior aponeurosis, which is the deeper structure requiring more invasive dissection to release during the Baumann procedure. In our experience, this allows for adequate fascial release for correction of equinus deformity with potentially less risk to the vital anatomic structures. This study demonstrated that the MGR posed less anatomic risk to the major neurovascular structures, such as tibial nerve and popliteal artery, whereas the great saphenous vein and saphenous nerve were in close proximity. As a result of this study, we have modified our operative technique as follows: instead of making a transverse incision as described in the Methods section, we now make a longitudinal incision, in line with the great saphenous vein and nerve to identify and retract these structures. Depending on the degree of contracture, a sequential lengthening may be performed by adding another fascial release 1 cm distal to the initial fascial release. The short- and long-term clinical outcomes as well as quantified improvement in dorsiflexion range of motion are yet to be investigated.
Gastrocnemius recession techniques have been widely employed to correct an IGC associated with various foot and ankle pathologies. Previous biomechanical investigation by Firth et al has demonstrated that the correction of equinus deformity by lengthening of the gastrocnemius-soleus complex differs in terms of range of correction. 7 We believe the degree of IGC should be stratified and an appropriate release technique employed to adequately correct the equinus deformity. In a patient with mild equinus deformity, the Strayer procedure may result in power and endurance deficits. To minimize risk of such a complication, we suggest a novel MGR at the proximal one-third of the muscle belly. If slightly more aggressive lengthening is desired, an additional lengthening can be performed slightly distally through the same incision.
When utilizing these techniques, it is also important to consider patient positioning. The standard PMGR technique requires prone positioning for an effective and safe release, whereas the Strayer procedure can be performed with the patient prone or supine with the leg externally rotated and elevated, the knee flexed, and ankle dorsiflexed. 10 It is important to consider positioning as IGC is often treated simultaneously with other foot and ankle pathologies, and the prone position can make addressing these more difficult. Our MGR technique allows for either supine or prone positioning, offering flexibility in intraoperative positioning.
Limitations of this study include the small sample of cadaveric specimens on which the dissections were performed and the ability to translate the information to surgery. A larger sample size would allow for account of a wider range of anatomic variants observed in the general population. Furthermore, the clinical implications of the anatomic proximity of these structures to the operative field during PMGR have not been demonstrated in any current literature to date. Further clinical studies are warranted to evaluate the rate at which at-risk structures presented in our study are injured iatrogenically. Despite the measured proximities, clinical awareness and meticulous operative technique may lead to lower rates of injury. This study does not provide a quantified analysis of deformity correction with each release.
In conclusion, this manuscript provides a historical perspective and an overview of the evolution of gastrocnemius recession techniques. It highlights the structures at risk during the PMGR techniques previously reported in the literature and currently used in the treatment of IGC. We have also proposed a novel technique for treating IGC, which may offer advantages to the previously described techniques. Further investigation is warranted to assess the clinical utility of our technique.
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 no financial support for the research, authorship, and/or publication of this article.