Bone remodelling along a titanium hip arthroplasty stem after resection of a chondrosarcoma

Long-term anchorage of cementless total hip arthroplasty relies on a direct bone to implant bonding. Several factors including material properties and surface treatment determine the interfacial response of the host bone to a foreign material. In the case presented, a chondrosarcoma of the proximal femur required an extended extraperiosteal resection. Reconstruction was possible with a titanium-alloy revision stem. A bony remodelling of the proximal femur was observed along the surface of the stem.

[Determination of the axis after totalendoprosthesis of the knee: functional X-ray photography as golden standard]

AIM

To examine the question of which X-ray photography technique should be given preference after implantation of total endoprosthesis of the knee.

METHOD

20 patients (age 74.1; 12 men, 8 women) with total endoprosthesis of the knee (Type Sigma, PFC, Johnson and Johnson) because of primary athrosis. Postoperatively X-ray photographs of the whole leg in standing and 40 x 20 a. p. in a flat position were taken. The angles of the axis were determined and the information analysed.

RESULTS

By means of X-ray photography of the whole leg we obtained the following angles: caput-collum-diaphyse 125 +/- 4.3 degrees, femur/basis of the knee 83.2 +/- 2.6 degrees, mechanical femur axis/basis of the knee 89.3 +/- 1.8 degrees, tibia/basis of the talus 89.2 +/- 2.2 degrees. With the 40 x 20 a. p. X-ray photographs we determined the following angles: femur/basis of the knee 82.3 +/- 3.1 degrees, basis of knee/tibia 92.2 +/- 3,6 degrees. Correlating the angles of femur/basis of the knee and basis of the knee/tibia were relations of 0.42 (p < 0.05) and 0.27 (p < 0.05).

CONCLUSION

For gaining information about the axis of the leg under functional conditions, one should give preference to X-ray photography of the whole leg.

[Radiological analysis of osseointegration after implantation of the Zweymüller-Alloclassic total hip system]

AIM

The purpose of this study was to identify typical radiological patterns of osseointegration following implantation of the Zweymüller-Alloclassic total hip system.

METHOD

The follow-up included the clinical and radiological evaluation of 115 consecutive hips. For each case the screw direction of the cup was calculated individually to fully observe the bony surroundings by properly tilted X-ray beam.

RESULTS

After 8.1 years, the Harris hip score was 88.5 points on average. Trabecular condensations leading toward the threads of the cup were observed in 100 cases, underlining the importance of the threads for load transfer. A complete intrusion of the threads into the pelvic bone was not accomplished in 23 cases with marked sclerosis of the acetabulum. The reduced connection, however, did not impair stability or function. The area of the distal stem is characterized by cortical hypertrophy and trabecular condensation of the neighbouring marrow. Linear radiolucencies were frequently observed in Gruen-Zone 1 and 7, in 5 cases extending into zone 2 and 6 without influence on the clinical function of the implant.

CONCLUSION

Material and geometry of the Zweymüller total hip lead to a load transfer through the threads of the cup. The integration of the stem relies on cortical interlocking. Proximal linear radiolucencies do not impair function. The signs of osseointegration around the cup can be fully demonstrated only by a specially tilted X-ray beam at a right angle to the screw direction of the cup.

[Clinical pedographic radiological findings after basal valgus osteotomy of metatarsal 1--a prospective study]

AIM

This study investigated the influence of valgusizing base wedge osteotomy of metatarsal 1 (MT 1) subsequently on the entire forefoot.

METHOD

Pre- and post-operatively 22 cases were investigated between 1998 and 2000 both clinically and radiologically with pedographic analysis in 20 of these cases.

RESULTS

According to the Kitaoka Score we could establish preoperative 37 and postoperative 72 out of 100 possible points. Following the MT 1-base wedge osteotomy with a distal soft-tissue procedure, the central forefoot region (MT 2/3) showed reduced pressure-induced pain, unchanged callus development, and reduced maximum load pressure. When the Plus-Index (MT 1 longer than MT 2) could be preserved in the valugusizing MT 1-base wege osteotomy, the metatarsalgia in the central forefoot region not only improved generally, but also the maximum loading pressure was clearly reduced. In cases with a post-operative Minus-Index (MT 1 shorter than MT 2), as well as in those Plus-Index cases undergoing a Keller procedure in the valgusizing base wedge osteotomy, the elevated pressure values in the central forefoot region persisted.

CONCLUSION

In valgusizing MT 1-base wege osteotomy with preservation of the Plus-Index (MT 1 longer MT 2), metatarsalgia can be improved and the maximum loading pressure in the central forefoot can be reduced.

[Parosteal lipoma]

Paraosteal lipoma is a rare benign tumour of the musculoskeletal system. It's features consist of a fatty component seated on a hypersotosis i.e. an exostose-like bone prominence. This tumor has a high tendency of metaplasia. Therefore chondroid elements may be present in addition to the fatty and bony components. Therapy of choice is complete surgical removal including the hyperostosis. Presenting this case the clinical and morphological characteristic of this rare tumour are discussed.

[The "empty" cruciate ligament notch. Aplasia or trauma aftereffect?]

Discoligamentary injuries of the knee frequently lead to an arthroscopic inspection of the joint. We present a case in which after two traumatic events a mensal tear and an empty notch were found on arthroscopic examination. The differential diagnosis of congenital aplasia of the anterior cruciate ligament (CAACL) versus neglected rupture of the ACL is discussed.