[Partial exchange in total hip arthroplasty : What can we combine?] / Gelenkteilwechsel in der Hüftarthroplastik : Was dürfen wir kombinieren?

BACKGROUND: In case of hip revision arthroplasty, one component (cup/stem) is often well fixed and does not need to be exchanged. The newly implanted component needs to be compatible with the well-fixed implant. The combination of implants from different companies leads to "mix and match" or even mismatch between the implants. OBJECTIVES AND METHODS: The objective of this work was to describe possible combinations including their specifications that need to be considered in partial exchange of hip prostheses. For this purpose the literature, surgical techniques of companies and judgements concerning this topic were analysed and our own results and experiences were included. RESULTS AND CONCLUSIONS: Partial revision arthroplasty can be challenging and needs to be planned in detail. In case of isolated cup or inlay revision with exchange of a modular head the cone of the stem needs to be identified. A ceramic head may be used in revision with a titanium sleeve even from a different company as long as they are compatible. Patients however need to give their informed consent for this mix and match procedure. This procedure is done frequently and good study results support this, however from a juristic point of view a definite recommendation cannot be given. If the inlay of a cup is replaced, the original inlay should be used. If this is not available anymore, it can be manufactured as a special product in many cases. If this is also not possible, an inlay can also be cemented into a well-fixed cup. Biomechanical and clinical studies support this off-label technique. In case of an isolated exchange of the stem with a ceramic inlay that is retained in a well-fixed cup, the revision stem and ceramic head need to be from the same company as the cup. In case of ceramic fracture, a ceramic head with a titanium sleeve should be combined with a PE or ceramic inlay, a metal head or inlay should never be used.

[Modified mini-Hardinge access for hip prosthesis implantation in the supine position]. / Modifizierter Mini-Hardinge-Zugang zur Implantation von Hüftgelenksprothesen in Rückenlage.

OBJECTIVE: Total hip arthroplasty with a minimal-incision technique that can be performed in the widely used supine position. The accustomed and good overview of this position allows safe positioning of the implant and combines this with the advantage of a soft tissue preserving technique. All standard instruments and implants can be further applied. INDICATIONS: Primary and secondary coxarthrosis, femoral head necrosis. CONTRAINDICATIONS: Revision surgery, severe anatomic deformity, implantation of hip resurfacing arthroplasty. SURGICAL TECHNIQUE: Supine position. The skin incision runs from the innominate tubercle proximally and falls slightly in the dorsal direction (20-30°). Incision of the iliotibial tract and exposure of the vastogluteal muscle sling. Starting from the greater trochanter, the sinewy onset of the minimal and medium gluteal muscle is split with an arched-shaped incision, which also falls proximally in the dorsal direction. Exposition of the joint capsule, longitudinal incision and resection of the ventrolateral parts. Dislocation of the hip by a combined adduction and external rotation movement. Osteotomy of the femoral neck and resection of the femoral head are performed in a figure-of-four position without adduction. To prepare the acetabulum and to insert the cup, the leg is placed in neutral position with a slight flexion of 20° in the hip. Preparation of the femur and implantation of the stem is again performed in a figure-of-four position in adduction. Reduction of the hip and stepwise wound closure. POSTOPERATIVE MANAGEMENT: Mobilization on postoperative day 1. Starting with half weight bearing and after completed wound healing rapid increase to full weight bearing. Intensive physiotherapy and rehabilitation. Thrombosis prophylaxis according to guidelines. RESULTS: The mini-incision approach has successfully been used in our clinic for years. Between September 2004 and November 2005, the less-invasive technique was evaluated in a randomized controlled trial with 51 patients (52 hips). Compared to the standard approach a significantly shorter incision length (8.9 vs. 14.0 cm) and a slightly lower blood loss (502 vs. 660 ml) were observed for the modified mini-Hardinge. Moreover, the mini-incision group showed slightly better functional results in the early course. A higher rate of implant malpositioning or a higher peri- and postoperative complication rate was not observed.

[Prognosis-adapted surgical management of bone metastases]. / Prognoseadaptierte operative Behandlung von Knochenmetastasen.

Surgery in metastatic disease to the bone is the most common procedure in orthopaedic oncology. To assess an adequate therapeutic approach we analysed 513 surgeries performed on 453 patients between 1980 and 2005 and reviewed the literature.The most significant factor is the histology of the primary tumour. A biopsy is mandatory to confirm the diagnosis in an unknown primary tumour, especially in cases of solitary lesions. Pulmonary carcinoma has an unfavourable prognosis compared to breast and renal cell carcinoma patients. Radical resection in isolated metastatic disease in renal cell carcinoma reduces the risk of local recurrence and even may result in a long progression-free survival. In breast cancer osseous and visceral dissemination is the most decisive factor for prognosis. An interdisciplinary approach is mandatory in every patient.

Proximal loading of the femur leads to low subsidence rates: first clinical results of the CR-stem.

INTRODUCTION: A new femoral stem was developed with a design that leads to compression of cancellous bone in the calcar region which results in proximal loading. The cross-sectional design of the implant provides rotational stability. MATERIALS AND METHODS: In the first clinical investigation ten patients underwent uncemented total hip arthroplasty between January 1999 and May 1999 using the CR-stem((R)) (Implantcast GmbH, Buxtehude, Germany). Results were investigated using the Harris-hip-score (HHS) and antero-posterior and lateral radiographs. Migration was evaluated with the EBRA-FCA-method with a follow-up of 7 years. RESULTS: We demonstrated a mean subsidence rate of 2.23 +/- 1.13 mm 7 years after implantation thus providing basic data for extensive testing in a clinical environment. DISCUSSION: As small subsidence rates are regarded as predictor for superior long-term results in uncemented total hip arthroplasty according to the literature, the CR-stem shows promise for excellent long-term results.