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Point-Counterpoint: Is A Lateral Release Necessary For Hallux Valgus Correction?
Yes.
Offering key anatomical pearls and biomechanical insights, this author notes that a lateral release is beneficial in the majority of surgical procedures for patients with hallux abducto valgus.
By Luke D. Cicchinelli, DPM, FACFAS
Have I ever performed surgery for the correction of hallux abducto valgus deformity without performing a lateral release and been happy with the clinical outcome? Yes. However, the vast majority of patients electing to undergo this surgery will benefit from the inclusion of some component of a lateral release, which helps ensure a more lasting and reliable result.
Would anyone argue that a medial release is not an integral part of the correction of hallux varus? This is doubtful. Is a medial release beneficial for the knee, another joint with a large sesamoid? Does a maltracking patella benefit from a lateral release? Sure, at least as a component of the surgical reconstruction.
Reflect on all the bunion surgeries you have performed over the years in which you and/or the patient were not completely satisfied with the radiographic or clinical result. What has been the common denominator in the failure to obtain perfection? Chances are the answer is residual or recurrent hallux valgus because of residual metatarsus primus varus or persistent and recurrent lateral drift of the hallux. Why? This is due to incomplete and/or temporary realignment of the metatarsal head over the sesamoid complex, which ensures a stably repaired, congruent first metatarsophalangeal joint (MPJ).
In fact, in spite of over 130 described procedures for correcting bunions, we know that any procedure will work if it corrects the bunion and all 130 have worked at some point for someone but no one procedure works for all. The lateral release is no different.
Let me simplify my position in this debate to what I will call the ABCs of bunion surgery. A is for anatomy, which is invariable and well described. A also stands for agonists, antagonists and axis of advantage around an articular axis. B is for biomechanics and for buckling, and the balance of them both. This is the balance or imbalance of A and B. C stands for congruence, cadaveric correlation and clinical confirmation. A full appreciation of the ABCs of bunion surgery readily leads to the conclusion that a lateral release is an integral component of achieving a reversal of the etiological forces that cause a bunion.
What You Should Know About Anatomy
Muscle-tendon complexes, ligaments, capsule and bone necessarily surround any joint. The pertinent structures surrounding the first MPJ are well understood. At the muscle tendon level on the plantar, medial and lateral sides of the joint, the abductor tendon heads oppose the adductor tendon heads, and the sesamoids are nestled in the heads of flexor hallucis brevis. The antagonistic muscles either work in concert or against each other, lending stability or perpetuating instability of the joint and the position of the great toe. The lateral ligaments include the deep transverse metatarsal ligament that binds the sesamoid apparatus to the plantar plates of the second MPJ plus the metatarsal sesamoid (suspensory) ligament and lateral collateral ligament.
The first MPJ is a four-bone joint where the sesamoids must reside in their grooves on the base of the metatarsal head and are intimately linked to the base of the phalanx. Which of these structures in the “lateral release” do hallux valgus surgeons routinely consider? Do we consider all structures or some structures in some cases and other structures in other cases?
With no uniformity in what constitutes a lateral release in spite of invariable anatomy, its necessity or lack thereof requires inherent consideration. There is an absolute tendency to perform a lateral release by rote, or not perform a lateral release and then focus on the osseous procedures required to correct the intermetatarsal angle. This is shortsighted and erroneously assumes that all bunions are created equal. The deformity requires a more flexible and real-time analysis intraoperatively.
Appreciating The Impact Of Biomechanical Imbalances
The reverse buckling of the hallux on the metatarsal head accentuates the intermetatarsal increase. Most of us clearly understand the general biomechanical instability of the medial column and first ray.
However, the biomechanical tendencies that contributed to the hallux abducto valgus can change during the surgical intervention itself. The adaptive contracture of the lateral soft tissues progressively pulls the phalanx into varying degrees of abduction and valgus/pronation. As this occurs, the base of the phalanx reverse buckles the intermetatarsal angle open even further. We intuitively know this from converse observations in intermetatarsal angle reduction after Keller bunionectomies and even true McBride procedures and first MPJ fusions. These are all cases in which no first metatarsal osteotomy occurred at all.
Indeed, the literature has shown that an effective lateral release itself can reduce the intermetatarsal angle between 2 and 5 degrees.1-3 This mandates continued intraoperative assessment as to the type of osteotomy and quantity of osseous correction required for further reduction of the intermetatarsal angle. In a sense, “as the phalangeal base goes, so go the sesamoids” via their insertion to the phalangeal base. Yet we know that the sesamoids remain immobile and it is the metatarsal head that becomes relocated over the sesamoid apparatus.4
So what should constitute a “lateral release” as an accepted definition for a debate of its merits? All that is required in the greatest preponderance of cases is a release of the fibular sesamoid or suspensory ligament, and the portion of the conjoined adductor/flexor hallucis brevis tendon between the lateral sesamoid and the base of the proximal phalanx. Those very structures are pulling the toe laterally or blocking the metatarsal head from relocating back over sesamoids. One should decide on the amount and necessity of such releases on a case by case basis for effective and reliably lasting correction of the deformity.
Pertinent Insights On Congruence, Cadaveric Correlation And Clinical Confirmation
A congruent joint is by definition not displaced so why would a lateral release be required? These are those infrequent cases of bunions that truly may not need a lateral release at all. However, incongruent joints are more the norm with hallux abducto valgus and have multiple static and dynamic anatomic components. The first metatarsal head drifts medially, thus increasing the angle between the first and second metatarsals. The transverse metatarsal ligament holds the sesamoid complex in place and thus becomes relatively laterally positioned as the metatarsal head displaces medially.
With a progressive deformity, the axis of pull for the adductor hallucis, the flexor hallucis brevis, the extensor hallucis longus and the abductor hallucis become lateralized, which dynamically contributes to the lateral displacement of the great toe. The medial joint capsule and ligaments become attenuated whereas the lateral joint capsule and ligaments become contracted. Ideally, an analysis of the amount of incongruence of the first MPJ and the amount of tension in the lateral soft tissue structures that is causative would allow us to tailor the amount of lateral release required for the case at hand.2
Hromadka and colleagues demonstrated on 30 cadaveric specimens with hallux valgus deformity that 90 percent required only a partial release of the conjoined lateral tendon and full release of the lateral fibular sesamoidal ligament to realign the joint.5 The authors considered less than 15 degrees of hallux abduction to be physiologic with simulated weightbearing and the fibular sesamoid relocated under the metatarsal head.
Kim and co-workers believe that the amount of lateral release also depends on the amount of lateral contracture and studied the role of intraoperative varus stress radiography to determine those cases in which surgeons could combine a lateral release with a distal Chevron osteotomy.6 They assessed the amount of lateral contracture by squeezing the metatarsal heads together under fluoroscopy intraoperatively and determining if one could passively reduce the hallux deformity. If one could reduce the deformity, then a lateral release in combination with a distal Chevron osteotomy worked well, even for higher intermetatarsal angles.
The authors also used tangential or axial fluoroscopy images to determine if one could reduce the metatarsal sesamoidal relationship and in those cases in which a metatarsal sesamoidal ligament release was not imperative.6
In Conclusion
What is the answer? Is a lateral release necessary for hallux valgus correction? Yes, in the vast majority of cases. The amount of release and its necessity require a dynamic approach and continued intraoperative assessment on a case by case basis. One should undertake a reasonable and prudent workup of those patients, eliciting for a history of surgical correction of their bunions. Preoperative radiographic assessment must consider joint congruity or incongruity in spite of the intermetatarsal angle. It is unwise to perform a lateral release routinely on all patients without considering the specific merits and severity of each case.
Intraoperative decision making via stress X-rays can help determine the passive reducibility of the hallux abducto valgus as well as the metatarsal head sesamoid alignment. All lateral soft tissue contractures are not created equal nor are their contributions to the reducibility of the pertinent anatomical structures. We must appreciate that as one performs a lateral release, the intermetatarsal angle will reduce due to the reduction of the buckling effect of the phalanx on the metatarsal head. It is mandatory to confirm clinically that one has neutralized and reversed the pathological forces that drew the hallux into abduction and valgus while opening the intermetatarsal angle.
Applying sound knowledge of the anatomy and the lateral structures to be released is still the most consistent assurance against the risk of the most likely complication: recurrent or residual hallux valgus deformity.
Dr. Cicchinelli is a Fellow of the American College of Foot and Ankle Surgeons. He is a faculty member of the Podiatry Institute. Dr. Cicchinelli is in private practice in Mesa, Ariz.
References
1. Mann RA, Coughlin MJ. Hallux valgus-etiology, anatomy, treatment and surgical considerations. Clin Orthop. 1981; 157:31-41.
2. Oloff LM, Bocko AP. Application of distal metaphyseal osteotomy for treatment of 357 high intermetatarsal angle bunion deformities. J Foot Ankle Surg. 1998; 37(6):481-489.
3. Bai LB, Lee KB, Seo CY, Song EK, Yoon TR. Distal chevron osteotomy with distal 365 soft tissue procedure for moderate to severe hallux valgus deformity. Foot Ankle Int. 2010; 31(8):683-688.
4. Judge MS, LaPointe S, Yu GV, Shook JE, Taylor RP. The effect of hallux abducto valgus surgery on the sesamoid apparatus position. J Am Podiatr Med Assoc. 1999; 89(11-12):551-559.
5. Hromádka R. Lateral release in hallux valgus deformity. From anatomical study to surgical tip. Submitted for publication to J Foot Ankle Surg, 2011.
6. Kim HN. Distal Chevron osteotomy with lateral soft tissue release for moderate to severe hallux valgus. Submitted for publication to J Foot Ankle Surg, 2012.
For further reading, see “Point-Counterpoint: Bunion Surgery: Should You Perform A Lateral Release?” in the August 2009 issue of Podiatry Today. To access the archives, visit www.podiatrytoday.com.
No.
This author says there are other techniques and cites studies showing that one can maintain hallux valgus correction without the need to perform a lateral release.
Surgeons have always considered release of the soft tissues about the lateral aspect of the first metatarsophalangeal joint (MPJ) to be an integral component in the correction of hallux valgus deformity.
There are many available techniques including an intracapsular release through a medial skin incision and a more traditional extracapsular release through either a separate lateral incision or the more standard dorsal incision. These approaches share a number of common components.
Typically, the surgeon frees the common adductor tendon (both transverse and oblique heads) from its insertion into the base of the proximal phalanx and fibular sesamoid, and severs the fibular sesamoidal ligament. One may or may not perform a lateral capsulotomy. On rare occasions, one may excise the fibular sesamoid. Additionally, transfer of the adductor tendon to the medial capsule or into the metatarsal neck is an option. Gaining surgical access to these structures from dorsal incisions also requires transection of the intermetatarsal ligaments.
Hallux valgus is a deformity in which the great toe laterally deviates or subluxes at the MPJ with the sesamoid visible in the interspace. Current concepts about the development of a bunion are predicated upon the unlocking of the MPJ in the pronated foot with the intrinsic lateral musculature, acting through the fibular sesamoid and pulling the toe into an abducted position. This creates a retrograde pressure that forces the metatarsal into adductus. It would appear to be intuitive to eliminate these lateral forces in order to correct a bunion and prevent its recurrence. Therefore, any effective lateral release should include the adductor tendons as well as the conjoined tendon of the fibular sesamoid. While logical, this remains a theory that has not been proven.
What You Should Know About The Sesamoids In Hallux Valgus
However, in the past decade or so, it has become accepted as fact that the sesamoids remain stationary in hallux valgus deformity. The prominence of the fibular sesamoid in the interspace and malalignment of the tibial sesamoid position are not the result of lateral drifting of the sesamoid complex, but of medial deviation of the first metatarsal. In fact, the sesamoids remain in their normal anatomic position throughout the development of hallux valgus deformity.
Coughlin and Mann as well as Jahss and Alvarez have commented on the fixed position of the sesamoids.1-3 Judge and co-workers published a multicenter review of hallux valgus surgery via Austin bunionectomy with an interspace release.4 One radiographic parameter they measured was the distance from the medial edge of the tibial sesamoid to the bisection of the second metatarsal shaft. They reported that this distance did not alter between pre-op and post-op X-rays. The authors concluded that the position of the sesamoids is fixed and the correction of hallux valgus should focus on moving the first metatarsal over the sesamoids.
Therefore, if we were to look for a baseline or normative structure to assess both the extent of deformity and degree of correction, it would be the relationship of the first metatarsal to the sesamoid complex. The sesamoid station is not affected by structure or mechanics, and this should be the standard by which we measure hallux valgus.
The hallux is intimately invested into the sesamoid apparatus via the plantar plate. This thick, dense fibrocartilaginous structure links the base of the proximal phalanx to the sesamoids. A study by Tanaka and colleagues looked at the relationship of the first metatarsal, second metatarsal and hallux in normal feet and those with hallux valgus, and confirmed this anatomic relationship.5 The authors demonstrated that with increasing degrees of metatarsus primus varus, the hallux did not drift medially with the first metatarsal but maintained its proximity to the second metatarsal and therefore the sesamoids as well.
“The base of the proximal phalanx in the hallux valgus foot was located on the same point as in the normal foot,” concluded Tanaka and colleagues.5 The authors concluded that hallux valgus is due to metatarsus primus varus and correction should include a lateral transfer of the metatarsal head.
David and co-workers reviewed the anatomy and function of the sesamoid apparatus.6 The muscles that insert into the sesamoids are vital in both structure and function to the normal foot. They help bind the first ray to the lesser rays, coordinate all of the forces on the five metatarsals and are involved in both shock absorption and propulsion.
Therefore, it has been established that in hallux valgus deformity, the sesamoids are in their normal anatomic position, the sesamoid complex is vital to propulsion, shock absorption and stability of the forefoot, and the hallux does not move medially as the first metatarsal moves into varus. The question then arises: Should we separate the sesamoids from their ligamentous and musculotendinous attachments if they are anatomically positioned and play a vital function in foot mechanics?
De-Emphasizing The Lateral Release: What The Studies Reveal
Certainly, the answer is not clear. Authors on both sides of the debate argue for or against interspace release, but there are few randomized, prospective, comparative studies. It does appear that as we move forward, the importance of releasing lateral structures is being minimized.
Lee and colleagues conducted a large prospective study comparing a Chevron osteotomy with and without soft tissue release.7 Seventy-four feet had soft tissue release and 78 had no release. The average pre-op hallux abductus angle was 29 degrees and the intermetatarsal angle was 16 degrees. Average post-op follow-up was 1.7 years with release and 2.1 years without release. The authors noted the post-op hallux abductus angle, intermetatarsal angle and AOFAS foot score differences were insignificant between the two groups. However, range of motion of the MPJ was significantly lower in the group with the interspace release.
In a prospective, randomized series in 1994, Resch compared 62 patients who underwent a Chevron osteotomy alone to 44 patients who underwent a Chevron osteotomy plus an adductor tenotomy.8 There was no difference in the satisfaction rate between the two groups.
I published a paper comparing results of Austin bunionectomy with and without interspace release.9 This long-term study looked at the results of 29 patients and 37 feet without any lateral release through an isolated medial incision. All patients had a minimum of one year of follow-up and an average follow-up of 18.4 months. I compared these results to the patients who had an Austin bunionectomy with complete interspace release in the study performed by Judge and colleagues several years earlier.4 Judge performed the measurements in both studies, acting as a neutral observer. This maintained consistency and affords a more accurate comparison between the two studies.
In my study, the intermetatarsal angle decreased by an average of 9.89 degrees and the hallux abductus angle reduced by 14 degrees.9 The greatest changes were in feet with intermetatarsal angles greater than 15 degrees. Overall, joint congruity was consistent with no evidence of recurrence. This compared favorably with the previously mentioned multicenter study, which reported an average reduction of 7.93 degrees of the intermetatarsal angle and 17.14 degrees of hallux abductus angle correction.4 The results demonstrated increased correction in the intermetatarsal angle by 2 degrees but 3 degrees less of hallux abductus angle correction in bunions with no interspace release in comparison to correction with interspace dissection.
I was consistently able to obtain better correction of the intermetatarsal angle by avoiding interspace release.9 A look at the anatomy reveals there are no significant structures that attach the first to second metatarsals proximally. All soft tissue intermetatarsal stability is in the distal forefoot. The intermetatarsal ligaments and the transverse and oblique heads of the adductor tendon provide transverse plane stability to the first ray. Severing these structures with an interspace release can contribute to instability and may help to explain why better intermetatarsal angle correction occurred without any lateral release. Anyone who has performed a complete lateral release can attest to placing the finger in the interspace and passing it to the plantar aspect of the foot, confirming all intermetatarsal soft tissue structures are now absent.
There was an approximate 2 to 3 percent increase in hallux abductus correction with a lateral release.9 A careful examination of postoperative X-rays often revealed a subtle varus angulation of the hallux when the lateral release was performed. This may explain the difference. Additionally, in the 15 years since I have stopped doing interspace releases, I have not had a single case of hallux varus.
Anecdotally, I have also seen a significant improvement in MPJ range of motion by eliminating the interspace dissection. This has been confirmed in studies from both Lee and co-workers and Granberry and Hickey.7,10
Additionally, in my study, I obtained sesamoidal axial projections on all bunions pre- and post-op.9 Relocation of the sesamoids into their anatomic grooves occurred without release of the fibular sesamoidal ligament.
Final Words
The concept of interspace release to remove deforming forces and allow relocation of the metatarsal head over the sesamoid apparatus is based upon the theory that metatarsus primus varus is secondary to hallux valgus. In 1928, McBride emphasized the importance of the lateral intrinsic musculature in the development of hallux valgus deformity.11 In 1977, Root and colleagues described the four stages of hallux valgus deformity.12 Their concept was that instability of the MPJ led to hallux abductus with secondary adductus of the first metatarsal.
More recent publications have clearly demonstrated the sesamoids and base of the hallux do not move in relation to the second metatarsal.13 The sesamoids also play a vital role in shock absorption and propulsion. Based upon these anatomical/mechanical facts, it is difficult to justify stripping these bones of their soft tissue attachments. Several studies have now clearly demonstrated complete correction of bunions without a lateral release and maintenance of that correction for at least two years.7,8 This concept is based upon anatomic facts and not theoretical conjecture regarding the development of hallux abducto valgus deformity.
Dr. Boberg is a faculty member of the Podiatry Institute and is in private practice in St. Louis. He is a former Director of Residency Training at SSM DePaul Hospital in St. Louis. Dr. Boberg can be reached via e-mail at: nailnpr@aol.com .
References
1. Mann RA, Coughlin MJ. Hallux valgus-etiology, anatomy, treatment and surgical considerations. Clin Orthop. 1981; 157:31-41.
2. Jahss MH. The sesamoids of the hallux. Clin Orthop Rel Res. 1981; 157:88-97.
3. Alvarez R, Haddad RJ, Gould N, Trevino S. The simple bunion: anatomy at the metatarsophalangeal joint of the great toe. Foot Ankle. 1984; 4(5):229-40.
4. Judge MS, LaPointe S, Yu GV, Shook JE, Taylor RP. The effect of hallux abducto valgus surgery on the sesamoid apparatus position. J Am Podiatr Med Assoc. 1999; 89(11-12):551-559.
5. Tanaka Y, Takakura Y, Sugimoto K, et al. Precise anatomic configuration changes in the first ray of the hallux valgus foot. Foot Ankle Int. 2000; 21(8):651-6.
6. David RD, Delagoutte, JP, Renard, MM. Anatomical study of the sesamoid bones of the first metatarsal. J Am Podiatr Med Assoc. 1989; 79(11):536-544.
7. Lee HJ, Chung JW, Chu IT, Kim YC. Comparison of distal Chevron osteotomy with and without lateral soft tissue release for the treatment of hallux valgus. Foot Ankle Int. 2010; 31(4):291-5.
8. Resch S, Stenstrom A, Reynisson K, Jonsson K. Chevron osteotomy for hallux valgus not improved by additional adductor tenotomy. Acta Orthop Scand. 1994; 65(5):541-544.
9. Boberg JS, Judge MS. Follow-up of the isolated medial approach to hallux abducto valgus correction without interspace release. J Am Podiatr Med Assoc. 2002; 92(10):555-562.
10. Granberry WM, Hickey CH. Hallux valgus correction with metatarsal osteotomy: effect of a lateral distal soft tissue procedure. Foot Ankle Int. 1995; 16(3):132-8.
11. McBride ED. A conservative operation for bunions. J Bone Joint Surg. 1928; 10:735-9.
12. Root ML, Orien WP, Weed JH. Forefoot deformity caused by abnormal subtalar joint pronation. In: Normal and Abnormal Functions of the Foot, Clinical Biomechanics, Root ML, Orien WP, Weed JH. (Eds), Clinical Biomechanics Corporation, Los Angeles 1977. Vol 2, p.376.
13. Saragas NP, Becker PJ, Comparative radiographic analysis of parameters in feet with and without hallus valgus. Foot Ankle Int. 1995; 16(3):139-143.
