Introduction: A long first metatarsal is a recognized contributing factor to the development of hallux rigidus. It is possible to identify a sub-group of patients with a long first metatarsal and early hallux rigidus. L.S. Barouk & P. Barouk have recently described the use of a modified Weil shortening osteotomy for the treatment of this sub-group of patients. The purpose of the study was to evaluate the early results of a modified Weil’s osteotomy of the first metatarsal in selected patients with hallux rigidus.

Materials and Methods: Fifteen patients with mild to moderate OA of the first MTP joint in whom the first metatarsal was at least as long as the second underwent a shortening and plantar-displacing Weil’s osteotomy.

Results: At a minimum follow-up of six months all patients’ symptoms improved dramatically and the range of motion was improved in all cases. One patient, a 19 year old professional footballer, developed a stress fracture of the second metatarsal which went on to heal and he was able to return to professional football. One patient developed transfer metatarsalgia. There were no cases of AVN and all patients were satisfied with the outcome of surgery.

Discussion: There are many treatment strategies for hallux rigidus. Fusion surgery provides excellent pain relief but joint preserving surgery is preferable. Cheilectomy is reliable but has a significant failure rate. Joint replacements remain experimental. Debridement of the joint in combination with longitudinal decompression of the first MTPJ provides greater range of motion than cheilectomy alone in the subgroup of patients who have a long first metatarsal.

Conclusions: These early results suggest that in selected individuals with hallux rigidus associated with a long first metatarsal, a modified Weil’s osteotomy can improve the range of motion of the first MTP joint and result in significant pain relief.

Ligamentous injury of the tarsometatarsal joint complex is uncommon but disabling. Injuries to individual ligaments can be visualised with MRI. The relative mechanical contribution of the three ligaments of the second TMTJ is unknown.

Methods

The second and third metatarsals and the first cuneiform were dissected from twenty pairs of cadaveric feet.

In group I, seven pairs were submaximally loaded to determine stiffness with the dorsal, plantar, and Lisfranc ligaments intact. One of each pair underwent sectioning of the dorsal ligament and was then loaded to failure. In the contralateral specimen both plantar and Lisfranc ligaments were divided before retesting.

In group II all 13 pairs underwent dorsal ligament excision and stiffness determination. One of each pair was randomly assigned to undergo sectioning of the plantar ligament, the other sectioning of the Lisfranc ligament, before retesting.

Results and Conclusions

The Lisfranc ligament is stronger and stiffer than the plantar ligament. The dorsal ligament is weaker than the Lisfranc/plantar complex. This suggests that ligamentous injuries of the second tarsometatarsal joint may be considered stable if the Lisfranc ligament is intact – even if the other two ligaments are disrupted. If the Lis-franc ligament is injured then the complex is less stiff and may be unstable.

The Mayo Conservative uncemented stem (Zimmer, Warsaw, USA) is designed to conserve proximal bone stock by virtue of a minimal neck resection and to maintain proximal femoral stress transfer, thereby reducing problems associated with stress shielding.

This study was performed to evaluate proximal femoral strain after implantation of the Mayo stem, in cadaveric femora.

Eight fresh-frozen cadaveric femora (each selected at random from within a pair) of known bone mineral density were prepared and coated with photoelastic materials (Measurements Group, Raleigh NC). Strain patterns of the intact bone were determined using a reflection polariscope, and recorded photographically, while under load. Quantitative measurements were taken from set points of the proximal femur. The femoral head was then replaced using a Mayo femoral prosthesis. Under the same loading conditions strain patterns were re-examined and measurements taken from the same set points.

The strain patterns following insertion of the Mayo stem closely matched those seen in intact femora except in two areas. Strain was reduced in the region of the lesser trochanter (53% of normal), although more proximal than this strain in the neck was closer to intact values (78% of normal). Previous studies have found that implantation of diaphyseal press fit stems in particular have led to significant reductions in shear strain values in the calcar region and distally along the medial border of the femur.

This study documents the strain pattern in the proximal femur after implantation with a new “conservative” short stem cementless prosthesis. The hypothesis that the Mayo femoral stem maintains proximal femoral stress transfer and may thus prevent stress shielding in vivo remains to be proven, but is supported by the results of this study.