Background. As hallux valgus (HV) worsens clinical and radiological signs of arthritis develop in metatarsophalangeal joint due to incongruity of joint surfaces. The purpose of this prospective study was to determine if intraoperative mapping of articular erosion of the first metatarsal head, base of the proximal phalanx, and tibial and fibular sesamoids can be correlated to clinical and/or radiographic parameters used during the preoperative assessment of the HV deformity. Materials and methods. We analysed 50 patients prospectively who underwent surgery between Jan 2009-Jan 2010. Patients with a known history of previous first metatarsophalangeal joint surgical intervention, trauma, or systemic arthritis were excluded from analysis. Preoperative demographics and AOFAS score were recorded. Intraoperative evaluation and quantification of the first metatarsal head, base of the proximal phalanx, and sesamoid articular cartilage erosion was performed. Cartilage wear was documented using International Cartilage Research Society grading. Results and Discussion. P. Bock et al have showed that the extent of cartilage lesions were clearly correlated with the degree of hallux valgus angle proving that a malaligned joint is more prone to cartilage degeneration. Kristen et al have described a correlation between a higher pre-operative hallux valgus angle and the post-operative Kitaoka et al score. The higher the preoperative hallux valgus angle, the lower the post-operative score. Our series showed the mean IMA is 15 degrees. The mean AOFAS score was 62. There was a significant positive correlation between hallux valgus angle and AOFAS score. We also found correlation between sesamoid wear and AOFAS score and HV angle. Conclusion. We conclude that preoperative clinical parameters (ie, age) and radiographic measurements (ie, HV, IMA) directly define the incidence and location of articular erosion and are helpful in the preoperative assessment of the HV deformity

Introduction. Despite the multiple patho-aetiological basis of Hallux valgus (HV), corrective osteotomy is a common and globally performed orthopaedic procedure. Over-correction of the inter-metatarsal angle (IMA), however, is not without consequence. Through increased joint pressures, over-correction may predispose to joint degeneration. Hypothesizing that over-correction leads to an increase in intra-articular joint pressures, we constructed a mechanical simulation of the 1. st. metatarsal-phalangeal joint. Methods. The vector forces of Flexor Hallucis Longus, Extensor Hallucis Longus, Extensor Hallucis Brevis and Adductor Hallucis, acting upon the 1. st. proximal phalanx were simulated with tensioned weighted rope. A Foley catheter balloon inflated to 1.5ml, simulated intra-articular distractive vector forces. The joint was freely mobile. At 5° IMA intervals from 10° valgus to 15° varus, intrarticular pressures were recorded using a contact pressure (Graseby™, Hertfordshire, UK) transducer attached to a calibrated manometer (Digitech Instruments™, Ulhasnagar, India). At each angle, measurements were repeated five times with removal and recalibration of the pressure monitor after each measurement. Results. A decline and subsequent increase in mean pressure was observed at each 5° interval from 10°valgus to neutral and then to 15° varus (mean±s.d.; 48.02±5.67, 24.72±1.01, 12.34±0.84, 18.96±2.46, 32.88±5.06, 42.92±4.99 milibar for 10°, 5° valgus, neutral, 5°, 10°and 15° varus IMA). One-way analysis of variance with post-hoc Tukey multiple comparison test revealed a significant increase in pressure from neutral and 5° valgus to 10° and 15° varus (p< 0.05). [First Metatarsal Phalangreal joint pressures]. Conclusion. This is the first description demonstrating increases in intrarticular pressures as the IMA tended from 5° to 15° varus, replicating inatrogenic Hallux Varus iatrogenically produced through osteotomy and over-correction of the IMA. Over-correction and increased intrarticular joint pressure may have an aetiological basis to post-operative 1. st. MTPJ degeneration. Over-correction is not a benign entity requiring consideration in Hallux Valgus corrective osteotomy