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Point-Counterpoint: Should You Release Soft Tissues For A Bunionectomy?

As this author argues, surgeons need to rebalance the soft tissues to facilitate long-lasting correction of hallux valgus deformities.

By William Fishco, DPM, FACFAS

With a couple of notable exceptions, I am a proponent of soft tissue release for the optimal correction of a bunion deformity. In a longstanding bunion deformity, there is adaptation of soft tissues. With lateral deviation of the great toe, the medial soft tissues have stretched out and the lateral tissues have become contracted. To that end, there needs to be rebalancing of soft tissues in addition to the osseous procedure(s), which is necessary to correct the abnormal metatarsal position.

As with any surgical procedure, there are certain controversies as to what procedure we should perform and how we should perform it. In regard to bone correction, some surgeons prefer distally based osteotomies and others may prefer midshaft or proximal osteotomies. Yet another group of surgeons may prefer a fusion of the first tarsometatarsal joint (Lapidus).

Each type of osteotomy has its own merits and it is difficult to say which is really best. Certainly, the main purpose of the bone work is to reduce the intermetatarsal angle and reposition the first metatarsal head over the sesamoid bones. I guess the bottom line is that you should perform whatever osteotomy you have the most confidence in when it comes to getting reproducible results.

In addition to controversy over the best location to perform the correctional osteotomy, there has been suspicion that the lateral release contributes to avascular necrosis of the first metatarsal head. Certainly, careful anatomic dissection and preserving soft tissues to the metatarsal (avoiding aggressive stripping of periosteum, dorsal synovial fold, etc.) lead to preservation of the blood supply to the metatarsal head. Studies have been published that disprove the theory of the lateral release causing avascular necrosis.1,2 I think we all agree that avascular necrosis of the first metatarsal head is rare and the etiology may be multi-factorial.

Pertinent Principles On Soft Tissue Rebalancing And Reducing Bunion Recurrence
After adequately addressing the first metatarsal bone to reduce the bunion deformity, soft tissue rebalancing is necessary to maintain the correction. In my mind, this is the most critical part of the bunionectomy. It is easy to get the metatarsal head over the sesamoids with bone work but how do you prevent the deformity from coming back? That is the real challenge. How many times have you performed a bunionectomy and it looked perfect on the table? Maybe it looked great for a few weeks afterward but you gradually saw a loss of correction over time. It happens to all of us. What causes this? The answer is the surgeon likely did not balance the soft tissues and if that is the case, there will likely be a loss of the desired correction.

The typical soft tissue rebalancing maneuvers include a lateral release, which includes detachment of the adductor tendon from the fibular sesamoid and release of the fibular sesamoid ligament. In addition, performing a medial capsulorrhaphy tightens the medial capsule. One may need to consider further lateral soft tissue release if there is not resolution of the deforming forces of the great toe joint. Using a stepwise approach, check the range of motion and load the foot during each step of the release. An additional release of the short head of the flexor tendon to the fibular sesamoid may be necessary. At times, I will remove part of the fibular sesamoid or the entire bone as a last resort (which rarely needs to happen). If the sesamoid is frozen, use a McGlamry elevator to break the adhesion.

At times, it may be tempting to lengthen the extensor hallucis longus tendon in cases of longstanding jumbo bunion deformities. Typically, there is a severely bowstrung tendon. I generally avoid doing anything to the tendon due to the concern of overlengthening or rupture of the tendon, which will ultimately lead to a drop hallux and/or a hallux malleus deformity. I can tell you from experience that this condition is difficult to fix and can be a nasty complication to address.

My philosophy on bunion corrections that will last over time includes performing whatever osteotomy you like that can place the metatarsal head over the sesamoids, obtaining a congruent great toe joint and resolving all deforming forces affecting the great toe joint during range of motion.

How do you know when the great toe joint is congruent? The answer is that the medial rim of the base of the proximal phalanx is sitting directly into the sagittal groove of the metatarsal head.
How do you know when you have resolved all deforming forces affecting the great toe joint? First, you should be able to load the forefoot (Kelikian push-up test) and the great toe does not deviate. One would perform a similar maneuver in hammertoe correction. Second, if you load the forefoot and the lesser toe deviates either in the transverse plane or sagittal plane, then you need to do more soft tissue balancing.

When examining great toe joint tissue balancing, you would not want the toe drifting in the transverse plane in either direction. If the toe drifts into varus, then you have been too aggressive in either the lateral release or with medial tightening. Conversely, if the toe laterally deviates upon loading, then you have more lateral release work to do to resolve that. Secondly, range of motion should be smooth in the sagittal plane. If the toe is stiff or tracking laterally, then chances are likely the correction will not hold up over time.

Key Exceptions That Would Preclude Soft Tissue Release
There are exceptions when performing a lateral release is not necessary. The first case includes a dorsal bunionectomy. In this instance, this is primarily a sagittal plane deformity versus a transverse plane deformity. Accordingly, there is typically no pathology of the soft tissues, which would necessitate transverse plane balancing. In a cheilectomy or decompression osteotomy with a cheilectomy, for example, no soft tissue releases are necessary.

The second scenario in which soft tissue releases are usually not necessary include bunionectomies for pediatric patients and/or young adults. In these cases, there has not been enough time for adaptations of the soft tissues. A good example would be a young adult with a metatarsus adductus foot type in which one performs a Lapidus bunionectomy. I will typically not even do any work at the first metatarsophalangeal joint. In these cases, there is no “bump” that has developed. Therefore, a modified McBride bunionectomy is not necessary.

In Conclusion
Soft tissue releases are necessary to achieve the ultimate goal of long-lasting correction of hallux valgus deformity. In order to keep the first metatarsal bone in place over the sesamoids, one needs to address all deforming soft tissue imbalances. Remember that the three elements of the perfect lasting bunionectomy include: relocating the first metatarsal head over the sesamoids, joint congruency and resolving all deforming forces affecting the great toe joint during range of motion.

Dr. Fishco is board-certified in foot surgery and reconstructive rearfoot and ankle surgery by the American Board of Podiatric Surgery. He is a Fellow of the American College of Foot and Ankle Surgeons, and is a faculty member of the Podiatry Institute. Dr. Fishco is in private practice in Phoenix.

References
1. Kuhn MA, Lippert FG 3rd, Phipps MJ, Williams C. Blood flow to the first metatarsal after chevron bunionectomy. Foot Ankle Int. 2005;26(7):526-9.
2. Peterson DA, Zilberfarb JL, Greene MA, Colgrove RC. Avascular necrosis of the first metatarsal head: incidence in distal osteotomy combined with lateral soft tissue release. Foot Ankle Int. 1994;15(2):59-63.

Editor’s note: For further reading, see “Addressing Complications Of Hallux Valgus Surgery” in the May 2014 issue of Podiatry Today.

For an enhanced reading experience, check out Podiatry Today on your iPad or Android tablet.

Emphasizing examples of sound radiographic and intraoperative assessment, and citing emerging research on frontal plane rotation and the chevron osteotomy, this author asserts that a lateral soft tissue release is not an absolute necessity with hallux valgus correction.

By Ronald Ray, DPM, FACFAS

The lateral soft tissue release is a common procedure that surgeons perform in conjunction with hallux valgus correction. However, one should determine the actual need for the release of the lateral soft tissues on a case-by-case basis, focusing on clinical, radiographic and intraoperative criteria. In some cases, a lateral soft tissue release is not necessary.      

Determining the need for a lateral soft tissue release can start with the clinical and radiographic examinations. Beginning with the clinical examination, distract the hallux and try to appreciate the extent of the opening between the lateral aspect of the first metatarsal head and the base of the proximal phalanx. Joints that permit lateral gapping with medial translation may have a greater degree of compliance of the soft tissues laterally. Then check the ease of reduction of the hallux from its abducted position to a neutral or adducted position. A rigid or abrupt endpoint (the “end feel of the joint”) may signify a contracted lateral side. In contrast, a more flexible or soft endpoint may be consistent with greater soft tissue compliance or forgiveness.1

After correcting the hallux to a neutral position, the range of motion from this point without significant recurrent deviation into abduction may signify that a less aggressive lateral soft tissue release may be necessary or that a lateral soft tissue release may not be necessary at all. Note that if the metatarsus primus adductus is quite rigid or non-reducible, it may not allow the full extent of hallux adduction to be apparent, and may squander the ability of the hallux to track in the sagittal plane in a normal manner. In this case, intraoperative assessment becomes critical.               

                 
When assessing an AP X-ray view, a highly subluxed and valgus rotated hallux may have more severe contracture laterally. However, if the surgeon can partially or completely reduce this component of the deformity, one should evaluate the need for the release. Review the sesamoid axial view carefully. If the sesamoid axial view demonstrates more transverse plane deviation of the first metatarsal without significant valgus rotation, the degree of lateral contracture may be limited and a lateral soft tissue release may not be necessary. Greater amounts of valgus rotation can potentially create more shortening or contracture of the lateral metatarsosesamoid suspensory ligament. If a lateral release is necessary, the lateral metatarsosesamoid suspensory ligament is likely the only segment that may need transection to achieve congruence of the joint.2-4

What The Research Reveals About Frontal Plane Rotation
Several authors have defined the frontal plane rotation of the first metatarsal in hallux valgus deformity. Scranton and Rutkowski measured frontal plane rotation of the first metatarsal in cadaveric specimens.5 Specimens with a hallux valgus deformity had an average of 14.5 degrees of valgus rotation of the first metatarsal whereas those specimens with no hallux valgus deformity had an average of 3.1 degrees. Mortier and colleagues measured 100 patients with hallux valgus deformity and were able to identify a mean radiographic pronation of 12.7 degrees.6 They concluded that metatarsal pronation in some cases occurs as a result of valgus rotation between the base of the first metatarsal and the metatarsal head.

In most cases, rotational instability from the first metatarsocuneiform joint drives pronation of the first metatarsal in hallux valgus deformity. If sesamoid displacement occurs primarily as a consequence of valgus rotation of the first metatarsal, then rotating the first metatarsal from a valgus position to a neutral or varus position should correct the sesamoid position without a lateral soft tissue release.

In a recent cadaveric investigation, Dayton and colleagues demonstrated the correlation between frontal plane rotation of the first metatarsal and the tibial sesamoid position.7 As the first metatarsal rotated into valgus (consistent with hallux valgus deformity in association with a metatarsus primus varus) the study showed a concomitant increase in the tibial sesamoid position. Bringing the first metatarsal into a more varus orientation resulted in a reduction in the tibial sesamoid position. The tibial sesamoid position was significant for both varus and valgus rotations.

Regarding the intermetatarsal angle, an increase in valgus rotation resulted in a statistically significant increase in the intermetatarsal angle.7 The soft tissues at the lateral aspect of the first metatarsophalangeal joint (MPJ) did not alter during this investigation. This investigation reveals the importance of frontal plane position of the first metatarsal and its direct influence on tibial sesamoid position and the first intermetatarsal angle, regardless of the state of “contracture” of the lateral soft tissues.      

The significance of the first metatarsal position in hallux valgus deformity gains further strength by looking at the relationship of the sesamoids to surrounding structures. Ramdass and Meyr retrospectively looked at 46 feet in 38 patients after metatarsal osteotomy to correct hallux valgus.8 Statistically significant differences in the first intermetatarsal angle, hallux abductus angle, tibial sesamoid position and tibial sesamoid grade were evident when comparing preoperative to postoperative values. The authors found no significant difference in the sesamoid position for the measured transverse or frontal plane relative to the second metatarsal. This investigation confirms that the sesamoids are relatively fixed in the transverse plane. It is a combination of transverse and frontal plane rotation of the first metatarsal that provides the correction of the tibial sesamoid position on the AP radiograph.  

Is A Lateral Soft Tissue Release Necessary With The Chevron Osteotomy?
Performing a chevron osteotomy without a lateral soft tissue release does not appear to compromise patient outcomes. Lee and colleagues compared two consecutive groups of patients undergoing a chevron osteotomy for hallux valgus deformity with and without a lateral soft tissue release.9 Radiographic changes and improvements in Ankle Orthopedic Foot and Ankle Society (AOFAS) scores were not statistically different between the groups. First MPJ range of motion was significantly better in the group that did not have a lateral soft tissue release. Other authors have noted a reduced first MPJ range of motion (joint stiffness) after a distal metatarsal osteotomy with lateral soft tissue release.10

Kim and coworkers utilized the varus stress test to determine whether an adjunctive lateral soft tissue release was necessary in patients with a mild to moderated bunion deformity undergoing a distal chevron osteotomy.1 The authors applied varus stress to the hallux to assess the need to perform a lateral soft tissue release. In 26 cases, the varus stress test revealed no lateral soft tissue contracture so surgeons did not perform a lateral release. In the remaining 22 cases, there was significant resistance to the varus stress test and surgeons performed a lateral release. At an average follow-up of 23 months (range 12 to 28 months), there was no statistically significant difference in the mean radiographic parameters measured or the AOFAS scores between the two groups.

In Conclusion
The lateral soft tissue release is not an absolute necessity when performing hallux valgus surgery. Careful preoperative evaluation in conjunction with intra-operative evaluation of the first MPJ once one has performed the medial capsulotomy is necessary before proceeding with a lateral soft tissue release. In some cases, a significant valgus rotation of the first metatarsal with hallux abductus may result in lateral metatarsosesamoid suspensory ligament contracture. Discrete release may be necessary in some cases to achieve optimal frontal and transverse plane correction of the first metatarsal and hallux.
Biomechanically, as the first metatarsal dorsiflexes and adducts, there is a component of valgus rotation. Valgus rotation of the first metatarsal creates the perception of an increased tibial sesamoid position and subsequent belief that contracture of the lateral soft tissues is imperative. Derotating the first metatarsal can correct the tibial sesamoid position in the absence of a lateral soft tissue release. Careful assessment of the first MPJ and first ray will reduce the need to release the lateral soft tissues to prevent the development of postoperative reduction in first MPJ range of motion.

Dr. Ray is in private practice at the Foot and Ankle Clinic of Montana in Great Falls, Mt. He is a Fellow of the American College of Foot and Ankle Surgeons, and a Diplomate of the American Board of Podiatric Surgery.

References

1. Kim HN, Suh DH, Hwang PS, Yu SO, Park YW. Role of intraoperative varus stress test for lateral soft tissue release during chevron bunion procedure. Foot Ankle Int. 2011; 32(4):362-367.
2. Schneider W, Knahr K. Keller procedure and chevron osteotomy in hallux valgus: five-year results of different surgical philosophies in comparable collectives. Foot Ankle Int. 2002; 23(4):321–329.
3. Schneider W. Influence of different anatomical structures on distal soft tissue procedure in hallux valgus surgery. Foot Ankle Int. 2012; 33(11):991–996.
4. Augoyard R, Largey A, Munoz MA, Canovas F. Efficacy of first metatarsophalangeal joint lateral release in hallux valgus surgery. Orthop Traumatol Surg Res. 2013; 99(4):425-431.
5. Scranton PE, Rutkowski R. Anatomic variations in the first ray. Part 1: anatomic aspects related to bunion surgery. Clin Orthop Rel Res. 1980; 151:244-255.
6. Mortier JP, Bernard JL, Maestro M. Axial rotation of the first metatarsal head in a normal population and hallux valgus patients. Orthop Traumatol Surg Res. 2012; 98(6):677-683.
7. Dayton P, Feilmeier M, Hirschi J, Kauwe M, Kauwe JS. Observed changes in radiographic measurements of the first ray after frontal plane rotation of the first metatarsal in a cadaver model. J Foot Ankle Surg. 2014; 53(3):274-278.
8. Ramdass R, Meyr AJ. The multiplanar effect of first metatarsal osteotomy on sesamoid position. J Foot Ankle Surg. 2010; 49(1):63-67.
9. Lee HJ, Chung JW, Chu IT, Kim YC. Comparison of distal chevron osteotomy with and without lateral soft tissue release for hallux valgus. Foot Ankle Int. 2010; 31(4):291-295.
10. Granberry WM and Hickey CH. Hallux valgus correction with metatarsal osteotomy:  effect of a lateral distal soft tissue procedure. Foot Ankle Int. 1995; 16(3):132-138.

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William Fishco, DPM, FACFAS, and Ronald Ray, DPM, FACFAS
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