Introduction: Advanced stages of first metatarsophalangeal (MTP) arthritis have traditionally been treated with resection arthroplasty or arthrodesis. Total- and hemiarthroplasty using various prosthetic replacements of the MTP joint, or phalangeal base, have been reported with variable success. A new metatarsal resurfacing system allows for intraoperative joint geometry mapping and placement of a contoured prosthetic.

Methods: Twenty-five patients with advanced stage hallux rigidus were included in this investigation and have undergone metatarsal head resurfacing (HemiCAP® Prosthesis, Arthrosurface Inc., Franklin, MA). The average age of the patients was 51 years. All patients were assessed with the Short Form 36 Health Survey (SF-36) and the American Orthopedic Foot and Ankle Society (AOFAS) clinical rating system for the Hallux, physical examination and radiographic evaluation. The average follow up was 20 months (range: 8 to 28 months).

Results: Postoperative passive dorsiflexion increased on average by 31 degrees from 34 degrees at baseline to 65 degrees at last follow-up. The mean AOFAS score improved from 44.1 to 82.1. The average SF-36 score improved from 81.2 to 96.1. The preoperative visual analogue pain score was reduced from 6.8 to 1.4 at last follow-up. No radiographic evidence of implant loosening, subsidence, or periprosthetic radiolucency has been found to date. No device failures have been encountered. All patients stated they would undergo the procedure again. One patient had a superficial wound break down which resolved with conservative care.

Conclusion: Although long term follow up is still necessary, the current results are very promising providing effective pain relief and improvement in range of motion. Proper implant placement does not affect the sesamoid groove. The procedure is performed with minimal joint resection and preserves viable bone stock, therefore conversion to arthrodesis or resection arthroplasty is possible should the need for further treatment arise.

We carried out a cross-sectional study in 51 patients (81 feet) with a clawed hallux in association with a cavus foot after a modified Robert Jones tendon transfer. The mean follow-up was 42 months (9 to 88). In all feet, concomitant procedures had been undertaken, such as extension osteotomy of the first metatarsal and transfer of the tendon of the peroneus longus to peroneus brevis, to correct the underlying foot deformity. All patients were evaluated clinically and radiologically. The overall rate of patient satisfaction was 86%. The deformity of the hallux was corrected in 80 feet. Catching of the big toe when walking barefoot, transfer lesions and metatarsalgia, hallux flexus, hallux limitus and asymptomatic nonunion of the interphalangeal joint were the most frequent complications. Hallux limitus was more likely when elevation of the first ray occurred (p = 0.012). Additional transfer of the tendon of peroneus longus to peroneus brevis was a significant risk factor for elevation of the first metatarsal (p < 0.0001). The deforming force of extensor hallucis longus is effectively eliminated by the Jones transfer, but the mechanics of the first metatarsophalangeal joint are altered. The muscle balance and stability of the entire first ray should be taken into consideration in the management of clawed hallux

Hallux rigidus was first described in 1887. Many aetiological factors have been postulated, but none has been supported by scientific evidence. We have examined the static and dynamic imbalances in the first metatarsophalangeal joint which we postulated could be the cause of this condition. We performed a finite-element analysis study on a male subject and calculated a mathematical model of the joint when subjected to both normal and abnormal physiological loads.

The results gave statistically significant evidence for an increase in tension of the plantar fascia as the cause of abnormal stress on the articular cartilage rather than mismatch of the articular surfaces or subclinical muscle contractures. Our study indicated a clinical potential cause of hallux rigidus and challenged the many aetiological theories. It could influence the choice of surgical procedure for the treatment of early grades of hallux rigidus.

Aims

The mainstay of surgical correction of hallux valgus is first metatarsal osteotomy, either proximally or distally. We present a technique of combining a distal chevron osteotomy with a proximal opening wedge osteotomy, for the correction of moderate to severe hallux valgus.