Limits...
Initial evaluation on subsidence of cemented collarless polished tapered stem applied to the patients with narrow femoral medullar canal.

Dairaku K, Ishii M, Kobayashi S, Kawaji H, Sasaki K, Takakubo Y, Takagi M - Open Orthop J (2010)

Bottom Line: In 39 of 45 cases, subsidence was appeared within six months after operation.Marked progressive and excessive subsidence was not seen after the two years of follow-up.Short term radiographic results of THA with CPT stem to small femur were satisfactory with less unfavorable radiographic findings, which imply contribution to longer survivorship of the stem.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan.

ABSTRACT

Purpose: The geometry of the proximal femur is one of the important factors for choosing the suitable stem. We have been applied cemented collarless polished tapered (CPT) stem to the patients with small femur. Radiographic evaluation was performed to access the clinical feature of the stem in early stage of the follow-up.

Methods: One hundred total hip arthroplasties with CPT system were performed between October 2004 to February 2006. This study focused on the 53 cases to whom size 1 or smaller sized stem were implanted, and its post-operative period was 41 months (30-46 months). Morphologic classification of preoperative proximal femur, stem alignment, thickness of the cement mantle, cementing technique, subsidence of the stem, improvement in the bone-cement interface, and stress shielding were assessed.

Results: The size of the inserted stem was X-SMALL in one case, SMALL in two cases, SIZE 0 in 12 cases, and SIZE 1 in 38 cases. Canal shape of proximal femur was stovepipe type in five cases, normal type in 43 cases, and champagne-flute type in five cases. There was no subsidence in eight cases. 44 stems subsided within 1 mm, one stem subsided 1 to 2 mm, and no stem subsided over 2 mm. In 39 of 45 cases, subsidence was appeared within six months after operation. Marked progressive and excessive subsidence was not seen after the two years of follow-up.

Conclusions: Short term radiographic results of THA with CPT stem to small femur were satisfactory with less unfavorable radiographic findings, which imply contribution to longer survivorship of the stem.

No MeSH data available.


First appearance of stem subsidence (%).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2864431&req=5

Figure 3: First appearance of stem subsidence (%).

Mentions: The stem size was distributed as X-SMALL in one case, SMALL in two cases, SIZE 0 in 12 cases, and SIZE 1 in 38 cases in order of a smaller size. Canal shape of proximal femur was evaluated by a parameter called canal flare index [2]. The average of canal flare index was 3.8±0.8 and stovepipe type was found in five cases (9.4%), normal type in 43 cases (81.2%), and champagne-flute type in five cases (9.4%) (Table 1). Stem alignment was 3° of valgus to 3° of vs in the antero-posterior plane, and its mean value was 0.1 ± 1.4° of vs position. In the lateral plane, stem alignment was 4° of anterior to 4° of posterior, and its mean value was 0.9 ± 1.7° of posterior position. The average thickness of cement mantle at zone 2, 3, 5, and 6, was 2.2 ± 0.6 mm (1-4 mm). The average thickness of cement mantle at zone 1 and zone 7 was 4.7 ± 2.5 mm (1-12 mm) and 7.1 ± 3.0 mm (2-15 mm). As for cementing technique, grade A was seen in 27 cases (51%). Grade B was seen in 18 cases (34.0%). Grade C was seen in eight cases (15.1%). Grade D was not seen (Table 2). Two of five cases, which shape of proximal femur was stovepipe, were grade C. Subsidence of the stem, which indicated “creep” phenomenon of the bone cement and stress relaxation by taper slip mechanism, was found in 45 cases (84.9%) at two year after operation, but eight cases (15.1 %) did not show subsidence. All subsidence was seen at stem-cement interface. Forty-four stems (83.0%) subsided within 1 mm, one stem (1.9%) subsided 1 to 2 mm, and no stem subsided over 2 mm. In 26 cases of 45 cases (57.8 %) which the subsidence was seen subsided within three months, 13 cases (28.9 %) subsided within six months, four cases (8.9 %) subsided within one year, and two cases (4.4%) subsided within two years (Fig. 3). In 39 of 45 cases (86.7 %), subsidence was appeared within six months after operation. Marked progressive and excessive subsidence was not seen after the two years of follow-up. As for the relationship to the canal shape, subsidence of the stem (0-2 mm) was found in three cases (60%) in stovepipe, 39 cases (90.7%) in normal, and three cases (60%) in champagne-flute, whereas, no subsidence was in two cases (40%) in stovepipe, eight cases (9.3%) in normal, and two cases (40%) in champagne- flute, respectively (Table 3). There was no significant difference (p = 0.051). In relationship to the cementing technique, subsidence of the stem (0-2 mm) was found in 23 cases (85.2%) in Barrack A, 16 cases (88.9%) in Barrack B, and six cases (75.0%) in Barrack C, but no subsidence was seven cases (14.8%), two cases (11.1%), three cases (25.0%), respectively. There was no significant difference (p = 0.658), but one case with grade C cementing technique showed subsidence of 1-2 mm (Table 4). Furthermore, there was no significant difference (p = 0.5) between subsidence and the thickness of cement mantle. There were six cases with less than 2 mm of cement mantle and subsidence was 0-1 mm in all cases. However, the number of cases will be increased in future, and there is a possibility that significant difference will be appeared. The limitation in this study is that evaluating factors which relates to the subsidence of the stem, such as the canal shape, the cement technique, and the cement mantle, are very limited and somewhat insufficient. It is important to evaluate detailed bone quality and the background of the patients before operation. A lot of factors might relate to the subsidence of polished stem. As for the relationship between cementing technique and canal shape, Barrack type C was found in two cases (40%) in stovepipe, six cases (14%) in normal, and none (0%) in champagne-flute. There was no significant difference (p = 0.49), but Barrack C was frequently found in stovepipe type femoral canal (Table 5).


Initial evaluation on subsidence of cemented collarless polished tapered stem applied to the patients with narrow femoral medullar canal.

Dairaku K, Ishii M, Kobayashi S, Kawaji H, Sasaki K, Takakubo Y, Takagi M - Open Orthop J (2010)

First appearance of stem subsidence (%).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864431&req=5

Figure 3: First appearance of stem subsidence (%).
Mentions: The stem size was distributed as X-SMALL in one case, SMALL in two cases, SIZE 0 in 12 cases, and SIZE 1 in 38 cases in order of a smaller size. Canal shape of proximal femur was evaluated by a parameter called canal flare index [2]. The average of canal flare index was 3.8±0.8 and stovepipe type was found in five cases (9.4%), normal type in 43 cases (81.2%), and champagne-flute type in five cases (9.4%) (Table 1). Stem alignment was 3° of valgus to 3° of vs in the antero-posterior plane, and its mean value was 0.1 ± 1.4° of vs position. In the lateral plane, stem alignment was 4° of anterior to 4° of posterior, and its mean value was 0.9 ± 1.7° of posterior position. The average thickness of cement mantle at zone 2, 3, 5, and 6, was 2.2 ± 0.6 mm (1-4 mm). The average thickness of cement mantle at zone 1 and zone 7 was 4.7 ± 2.5 mm (1-12 mm) and 7.1 ± 3.0 mm (2-15 mm). As for cementing technique, grade A was seen in 27 cases (51%). Grade B was seen in 18 cases (34.0%). Grade C was seen in eight cases (15.1%). Grade D was not seen (Table 2). Two of five cases, which shape of proximal femur was stovepipe, were grade C. Subsidence of the stem, which indicated “creep” phenomenon of the bone cement and stress relaxation by taper slip mechanism, was found in 45 cases (84.9%) at two year after operation, but eight cases (15.1 %) did not show subsidence. All subsidence was seen at stem-cement interface. Forty-four stems (83.0%) subsided within 1 mm, one stem (1.9%) subsided 1 to 2 mm, and no stem subsided over 2 mm. In 26 cases of 45 cases (57.8 %) which the subsidence was seen subsided within three months, 13 cases (28.9 %) subsided within six months, four cases (8.9 %) subsided within one year, and two cases (4.4%) subsided within two years (Fig. 3). In 39 of 45 cases (86.7 %), subsidence was appeared within six months after operation. Marked progressive and excessive subsidence was not seen after the two years of follow-up. As for the relationship to the canal shape, subsidence of the stem (0-2 mm) was found in three cases (60%) in stovepipe, 39 cases (90.7%) in normal, and three cases (60%) in champagne-flute, whereas, no subsidence was in two cases (40%) in stovepipe, eight cases (9.3%) in normal, and two cases (40%) in champagne- flute, respectively (Table 3). There was no significant difference (p = 0.051). In relationship to the cementing technique, subsidence of the stem (0-2 mm) was found in 23 cases (85.2%) in Barrack A, 16 cases (88.9%) in Barrack B, and six cases (75.0%) in Barrack C, but no subsidence was seven cases (14.8%), two cases (11.1%), three cases (25.0%), respectively. There was no significant difference (p = 0.658), but one case with grade C cementing technique showed subsidence of 1-2 mm (Table 4). Furthermore, there was no significant difference (p = 0.5) between subsidence and the thickness of cement mantle. There were six cases with less than 2 mm of cement mantle and subsidence was 0-1 mm in all cases. However, the number of cases will be increased in future, and there is a possibility that significant difference will be appeared. The limitation in this study is that evaluating factors which relates to the subsidence of the stem, such as the canal shape, the cement technique, and the cement mantle, are very limited and somewhat insufficient. It is important to evaluate detailed bone quality and the background of the patients before operation. A lot of factors might relate to the subsidence of polished stem. As for the relationship between cementing technique and canal shape, Barrack type C was found in two cases (40%) in stovepipe, six cases (14%) in normal, and none (0%) in champagne-flute. There was no significant difference (p = 0.49), but Barrack C was frequently found in stovepipe type femoral canal (Table 5).

Bottom Line: In 39 of 45 cases, subsidence was appeared within six months after operation.Marked progressive and excessive subsidence was not seen after the two years of follow-up.Short term radiographic results of THA with CPT stem to small femur were satisfactory with less unfavorable radiographic findings, which imply contribution to longer survivorship of the stem.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan.

ABSTRACT

Purpose: The geometry of the proximal femur is one of the important factors for choosing the suitable stem. We have been applied cemented collarless polished tapered (CPT) stem to the patients with small femur. Radiographic evaluation was performed to access the clinical feature of the stem in early stage of the follow-up.

Methods: One hundred total hip arthroplasties with CPT system were performed between October 2004 to February 2006. This study focused on the 53 cases to whom size 1 or smaller sized stem were implanted, and its post-operative period was 41 months (30-46 months). Morphologic classification of preoperative proximal femur, stem alignment, thickness of the cement mantle, cementing technique, subsidence of the stem, improvement in the bone-cement interface, and stress shielding were assessed.

Results: The size of the inserted stem was X-SMALL in one case, SMALL in two cases, SIZE 0 in 12 cases, and SIZE 1 in 38 cases. Canal shape of proximal femur was stovepipe type in five cases, normal type in 43 cases, and champagne-flute type in five cases. There was no subsidence in eight cases. 44 stems subsided within 1 mm, one stem subsided 1 to 2 mm, and no stem subsided over 2 mm. In 39 of 45 cases, subsidence was appeared within six months after operation. Marked progressive and excessive subsidence was not seen after the two years of follow-up.

Conclusions: Short term radiographic results of THA with CPT stem to small femur were satisfactory with less unfavorable radiographic findings, which imply contribution to longer survivorship of the stem.

No MeSH data available.