The selection of the stem implant and its type of fixation in the femoral cavity (cemented or uncemented fixation) seems to have an impact on the bone mineral density of the acetabulum. Long-term clinical follow-up is required to draw conclusions regarding the influence on prosthesis survival.

Ochronotic arthropathy is a rare condition found in patients with alkaptonuria. Due to the accumulation of homogentisic acid, cartilages get a dark discoloration and become brittle and more vulnerable to mechanical stress (Centinus et al. Rheumatol Int 3:127-131, 2004; Hamdi et al. Int Orthop 23:122-125, 1999; Phornphutkul, N Engl J Med 347:2111-2121, 2002; Thacker, Arthroscopy 19:14-17, 2003). This case report is about a patient first diagnosed for ochronosis by arthroscopy of the knee. Her brother was having similar complaints during follow-up. Both patients were prescribed to take glucosamine and chondroitine. Although no report is found in the literature, regarding the success of this therapy in patients with ochronosis, both patients reported a positive effect on articular pain and daily activities

BackgroundHip surface replacement arthroplasty (SRA) can be an alternative for total hip arthroplasty. The short and long-term outcome of hip surface replacement arthroplasty mainly relies on the optimal size and position of the femoral component. This can be defined before surgery with pre-operative templating. Reproducing the optimal, templated femoral implant position during surgery relies on guide wire positioning devices in combination with visual inspection and experience of the surgeon. Another method of transferring the templated position into surgery is by navigation or Computer Assisted Surgery (CAS). Though CAS is documented to increase accurate placement particularly in case of normal hip anatomy, it requires bulky equipment that is not readily available in each centre.MethodsA custom made neck jig device is presented as well as the results of a pilot study.The device is produced based on data pre-operatively acquired with CT-scan. The position of the guide wire is chosen as the anatomical axis of the femoral neck. Adjustments to the design of the jig are made based on the orthopedic surgeon's recommendations for the drill direction. The SRA jig is designed as a slightly more-than-hemispherical cage to fit the anterior part of the femoral head. The cage is connected to an anterior neck support. Four knifes are attached on the central arch of the cage. A drill guide cylinder is attached to the cage, thus allowing guide wire positioning as pre-operatively planned.Custom made devices were tested in 5 patients scheduled for total hip arthroplasty. The orthopedic surgeons reported the practical aspects of the use of the neck-jig device. The retrieved femoral heads were analyzed to assess the achieved drill place in mm deviation from the predefined location and orientation compared to the predefined orientation.ResultsThe orthopedic surgeons rated the passive stability, full contact with neck portion of the jig and knife contact with femoral head, positive. There were no guide failures. The jig unique position and the number of steps required to put the guide in place were rated 1, while the complexity to put the guide into place was rated 1-2. In all five cases the guide wire was accurately positioned. Maximum angular deviation was 2.9° and maximum distance between insertion points was 2.1 mm.ConclusionsPilot testing of a custom made jig for use during SRA indicated that the device was (1) successfully applied and user friendly and (2) allowed for accurate guide wire placement according to the preoperative plan.

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