Correction of clawed hallux deformity: comparison of the Jones procedure and FHL transfer in a cadaver model

Arthroscopically Assisted Modified Jones Procedure

The modified Jones procedure is the classic operative treatment of symptomatic clawed hallux. It is composed of transfer of the extensor hallucis longus tendon to the first metatarsal neck and fusion of the hallux interphalangeal joint. The purpose of this technical note is to report the technique of an arthroscopically assisted modified Jones procedure. This can be combined with other minimally invasive bone and soft-tissue procedures to correct all aspects of the complex cavus foot deformity.

Forefoot tendon transfers

Flexible forefoot deformities, such as hallux varus, clawed hallux, hammer toes, and angular lesser toe deformities, can be treated effectively with tendon transfers. Based on the presentation of the flexible forefoot deformities, tendon transfers can be used as the primary treatment or as adjuncts to bony procedures when there are components of fixed deformities.

Finite element analysis of the foot: model validation and comparison between two common treatments of the clawed hallux deformity

BACKGROUND

Clawed hallux is defined by first metatarsophalangeal joint extension and first interphalangeal joint flexion; it can increase plantar pressures and ulceration risk. We investigated two corrective surgical techniques, the modified Jones and flexor hallucis longus tendon transfer.

METHODS

A finite element foot model was modified to generate muscle overpulls, including extensor hallucis longus, flexor hallucis longus and peroneus longus. Both corrective procedures were simulated, predicting joint angle and plantar pressure changes.

FINDINGS

The clawed hallux deformity was generated by overpulling: 1) extensor hallucis longus, 2) peroneus longus + extensor hallucis longus, 3) extensor hallucis longus + flexor hallucis longus and 4) all three together. The modified Jones reduced metatarsophalangeal joint angles, but acceptable hallux pressure was found only when there was no flexor hallucis longus overpull. The flexor hallucis longus tendon transfer reduced deformity at the metatarsophalangeal and interphalangeal joints but may extended the hallux due to the unopposed extensor hallucis longus. Additionally, metatarsal head pressure increased with overpulling of the extensor hallucis longus + flexor hallucis longus, and all three muscles together.

INTERPRETATION

The modified Jones was effective in correcting clawed hallux deformity involving extensor hallucis longus overpull without flexor hallucis longus overpull. The flexor hallucis longus tendon transfer was effective in correcting clawed hallux deformity resulting from the combined overpull of both extensor and flexor hallucis longus, but not with isolated extensor hallucis longus overpull. An additional procedure to reduce the metatarsal head pressure may be required concomitant to the flexor hallucis longus tendon transfer. However this procedure avoids interphalangeal joint fusion.

The development of an intraoperative plantar pressure assessment device

BACKGROUND

The goal of this study was to develop an accurate and reliable supine plantar pressure measurement apparatus that could potentially be used in the operating room to guide operative decision making. It was hypothesized that plantar pressures would be similar in supine and vertical posture trials.

MATERIALS AND METHODS

A supine plantar pressure system was developed using the Pliance 32 sensor array (Novel, Munich, Germany). Accuracy was tested with a standardized manometer and the Trublu calibration system (Novel). Next, bilateral feet of 10 healthy, asymptomatic patients were tested in the apparatus by two separate investigators. Intraclass correlation coefficients (ICC) were calculated to determine intrarater and interrater reliability for parameters of average mean pressure (AMP), peak pressure (PP) and percentage of total force (PF). Finally, plantar pressures were tested in vertical posture and compared to supine parameters.

RESULTS

The sensor was both linear and accurate. The ICC values demonstrated that the sensor was reliable for AMP (0.66 to 0.93), PP (0.75 to 0.94), and PF (0.69 to 0.97). In general, AMP, PP, and PF values were significantly different at most anatomical regions for supine and vertical posture trials (p < 0.0001).

CONCLUSION

This intraoperative pressure measurement system provided an accurate, linear, and reliable method to measure plantar pressure parameters in the supine subject. These measures were similar in magnitude to vertical posture, but were statistically different.

CLINICAL RELEVANCE

This intraoperative plantar pressure system could guide operative reconstruction of foot deformities whose outcome depends on the distribution of pressures across the plantar foot.

Chronic diabetic ulcers under the first metatarsal head treated by staged tendon balancing

We studied a cohort of 26 diabetic patients with chronic ulceration under the first metatarsal head treated by a modified Jones extensor hallucis longus and a flexor hallucis longus transfer. If the first metatarsal was still plantar flexed following these two transfers, a peroneus longus to the peroneus brevis tendon transfer was also performed. Finally, if ankle dorsiflexion was < 5° with the knee extended, a Strayer-type gastrocnemius recession was performed.

The mean duration of chronic ulceration despite a minimum of six months’ conservative care was 16.2 months (6 to 31). A total of 23 of the 26 patients were available for follow-up at a mean of 39.6 months (12 to 61) after surgery. All except one achieved complete ulcer healing at a mean of 4.4 weeks (2 to 8) after surgery, and there was no recurrence of ulceration under the first metatarsal.

We believe that tendon balancing using modified Jones extensor hallucis longus and flexor hallucis longus transfers, associated in selected cases with a peroneus longus to brevis transfer and/or Strayer procedure, can promote rapid and sustained healing of chronic diabetic ulcers under the first metatarsal head.

Tenotomy and tendon transfer about the forefoot, midfoot and hindfoot

Tendon lengthening and transfer are essential surgical procedures for every foot and ankle surgeon to master, because they are useful in restoring balance and correcting flexible foot deformities. These techniques are even more useful in treating the high-risk patient, because they involve minimal soft-tissue injury and maximum preservation of vascularity. The primary goal of this article is to supplement the foot and ankle surgeon's options for treating static and dynamic foot deformities in the high-risk patient by discussing useful tendon lengthening and transfer procedures about the forefoot, midfoot, and hindfoot.