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First Tarsometatarsal Joint Loading After Sequential Correction of Hallux Valgus Using a Proximal Opening Wedge Metatarsal Osteotomy and Distal Soft Tissue Procedure.

ABSTRACT:

Background

The proximal opening wedge osteotomy (POWO) of the first metatarsal (TMT-1) is commonly performed in the operative treatment of hallux valgus. Limited work has been dedicated to study POWO's effect on the TMT-1 joint, however. The purpose of this study is to evaluate the changes in TMT-1 joint contact stress following POWO of the first metatarsal.

Methods

Five fresh-frozen cadaveric below-knee specimens (mean age: 73 years) with hallux valgus deformities (mean hallux valgus angle [HVA]: 37.4 ± 8.5 degrees) were studied. The specimens were loaded to 400 N on an MTS servohydraulic load frame. Joint contact characteristics at TMT-1 joint were measured with a Tekscan pressure sensor (Model 6900, 1100 psi; Tekscan Inc, Boston, MA) with various opening wedge sizes of 3, 5, and 7 mm both without and with a distal soft tissue release (DSTR). The contact force, area, and peak contact stress were compared among groups using analysis of variance and post hoc multiple comparisons over the untreated (Dunnett test, P < .05).

Results

The mean contact force was 47.7 ± 33.5 N for untreated specimens. This increased sequentially with opening wedge size and reached statistical significance for 7-mm opening wedge (129.7 ± 62.3 N, P = .01) and 7-mm wedge + DSTR (134.8 ± 60.5 N, P = .008). The mean peak contact stress was 2.8 ± 1.3 MPa for the untreated specimens and increased incrementally with wedge size to 5.7 ± 3.0 MPa for 7-mm wedge only (P = .03) and 5.6 ± 2.5 MPa for 7-mm wedge + DSTR (P = .05). The contact area increased with corrections, but none reached significance.

Conclusion

With increasing opening wedge size, loading of the TMT-1 joint increases. Joint stresses higher than 4.7 MPa have been shown to be chondrotoxic, potentially predisposing patients to arthritic joint changes following POWO.

Level of evidence

XXXXXX.

SUBMITTER: Kraus J

PROVIDER: S-EPMC8702668 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundWhile proximal first metatarsal osteotomy combined with distal soft tissue realignment is accepted as standard treatment of moderate to severe hallux valgus with metatarsus primus varus, none of the described proximal metatarsal osteotomies address the hyper-obliquity of the first metatarsocuneiform joint. An opening-wedge osteotomy of the medial cuneiform can potentially correct the 1-2 intermetatarsal angle (IMA) in addition to normalizing the hyper-obliquity of the first tarsometatarsal (TMT) joint. The purpose of this study was to retrospectively review the early radiographic and clinical results of the use of a medial cuneiform opening-wedge osteotomy fixed with a low-profile wedge plate combined with distal soft tissue realignment for the treatment of hallux valgus.MethodsFourteen feet (13 patients; 2 male and 11 female, average age 56 years, range 22-75) with hallux valgus underwent an opening-wedge osteotomy of the medial cuneiform fixed with a low-profile nonlocking wedge plate combined with distal soft tissue realignment. The mean preoperative hallux valgus angle (HVA) was 32 degrees and the IMA was 16 degrees. HVA, 1-2 IMA, proximal first metatarsal inclination (PFMI), and presence of osteoarthritis of the first TMT joint were assessed on preoperative and final postoperative radiographs. Final postoperative radiographs were also evaluated for radiographic union and hardware failure at an average of 7 months (range, 3-19 months) postoperatively.ResultsA mean intraoperative correction of 19 degrees and 7 degrees was achieved for the HVA and IMA, respectively. The mean HVA was 22 degrees and the mean IMA was 11 degrees at the time of final follow-up. At final follow-up, a recurrence of the deformity was observed in 12/14 feet. There were 2 nonunions-one plate failure and one screw failure. No first TMT joint instability or arthritis was observed. All patients were ambulatory without assistive device in either fashionable or comfortable shoe wear.ConclusionMedial cuneiform opening-wedge osteotomy resulted in unreliable correction of HVA and IMA at short-term follow-up with a high rate of early recurrence of hallux valgus deformity and a complication rate similar to that of the Lapidus procedure. This procedure cannot be recommended for addressing hallux valgus in the setting of increased obliquity of the first TMT joint.Level of evidenceLevel IV, case series.