[Our experience with the metha short hip stem]

The aim of the study was to evaluate the clinical and radiographic results of total hip arthroplasty (THA) with the Metha short hip stem and their comparison with the outcomes of THA using a conventional cementless stem.

A total of 30 Metha stems and 30 standard Biocontact stems implanted in the period from 2007 to 2012 were evaluated. The Metha patient group comprised 22 women and six men, with the mean age of 58.9 ± SD 8.7 years (43-75), mean height of 164.2 ± 6.3 cm (156-178), mean body mass of 68.2 ± 12 (48-91) and mean BMI of 25 ± 3.9 (19-32). The Biocontact group included 19 women and 11 men, with the mean age of 63.6 ± 10.8 years (45-77), mean height of 166.6 ± 6.6 cm (152-175), mean body mass of 77.6 ± 13.1 (46-104) and mean BMI of 27.6 ± 4.3 (20-37). The evaluation was based on plain X-ray findings and clinical status assessed using the Harris hip score and 10-point visual analogue scale (VAS) for pain before surgery and at final follow-up.

In the Metha group the mean pre- and post-operative Harris hip scores were 41.7 ± 9.9 (28-57) and 94.4 ± 5.1 (82-100), respectively. In the Biocontact group the values were 41.5 ± 11.9 (32-64) and 89.3 ± 11.2 (57-100), respectively. The mean VAS for low back and thigh pain improved from the pre-operative value of 7.41 ± 2.1 (4-9) to 0.56 ± 1.0 (0-3) in the Metha group and from 7.29 ± 2.2 (4-9) to 1.64 ± 1.8 (0-5) in the Biocontact group. The post-operative results in both rating systems were significantly better (p<0.05) in the Metha than the Biocontact group patients. All stems showed radiographic evidence of good osteointegration. Stem subsidence and calcar atrophy were recorded in one patient of the Metha group. In the Biocontact group stem subsidence was found in two patients and signs of stress shielding in 14 patients.

Short hip stems have been introduced in THA implantation with the aim to restore physiological biomechanics as much as possible and to ensure good long-term functioning of the joint replacement as well as to save the proximal femoral bone tissue for potential THA re-implantation. Our results of short hip stem implantation presented in this study are compared with the results of relevant recently published literature.

Short hip stems show adequate osteointegration without need for diaphyseal fixation and allow for more natural weightbearing distribution in the proximal femur. The short- and mid-term clinical results are better than with the use of conventional cementless stems. They can be recommended as an optimal choice for use in younger patients with good bone quality who are expected to require THA re-implantation.