1.Revision Total Hip Arthroplasty for Spongy Metal Lübeck Hip Prosthesis with Repeated Stem Fracture and Periprosthetic Femur Fractures: A Case Report
Takuya NAKAI ; Shigeo FUKUNISHI
Hip & Pelvis 2024;36(4):320-325
The fully porous structure of the Lübeck prosthesis is designed to closely resemble cancellous bone. Several studies have reported ‘good’ to ‘excellent’ mid- to long-term results for use of the Lübeck, but stem fractures have been reported as a complication. We report on the case of an 85-year-old patient who underwent total hip arthroplasty (THA) using the Lübeck more than 25 years ago who underwent revision surgery for management of two periprosthetic femoral fractures and a stem fracture. A subtrochanteric fracture and a fracture of the stem were observed on radiographs, and a radiolucent line was observed in the proximal portion of the stem and a well-fixed distal portion was observed. Revision THA using a proximal femoral replacement stem and resection of the proximal femur has been proven as an effective procedure for treatment of an elderly patient with a fractured Lübeck stem with a well-fixed distal stem.
2.Revision Total Hip Arthroplasty for Spongy Metal Lübeck Hip Prosthesis with Repeated Stem Fracture and Periprosthetic Femur Fractures: A Case Report
Takuya NAKAI ; Shigeo FUKUNISHI
Hip & Pelvis 2024;36(4):320-325
The fully porous structure of the Lübeck prosthesis is designed to closely resemble cancellous bone. Several studies have reported ‘good’ to ‘excellent’ mid- to long-term results for use of the Lübeck, but stem fractures have been reported as a complication. We report on the case of an 85-year-old patient who underwent total hip arthroplasty (THA) using the Lübeck more than 25 years ago who underwent revision surgery for management of two periprosthetic femoral fractures and a stem fracture. A subtrochanteric fracture and a fracture of the stem were observed on radiographs, and a radiolucent line was observed in the proximal portion of the stem and a well-fixed distal portion was observed. Revision THA using a proximal femoral replacement stem and resection of the proximal femur has been proven as an effective procedure for treatment of an elderly patient with a fractured Lübeck stem with a well-fixed distal stem.
3.Revision Total Hip Arthroplasty for Spongy Metal Lübeck Hip Prosthesis with Repeated Stem Fracture and Periprosthetic Femur Fractures: A Case Report
Takuya NAKAI ; Shigeo FUKUNISHI
Hip & Pelvis 2024;36(4):320-325
The fully porous structure of the Lübeck prosthesis is designed to closely resemble cancellous bone. Several studies have reported ‘good’ to ‘excellent’ mid- to long-term results for use of the Lübeck, but stem fractures have been reported as a complication. We report on the case of an 85-year-old patient who underwent total hip arthroplasty (THA) using the Lübeck more than 25 years ago who underwent revision surgery for management of two periprosthetic femoral fractures and a stem fracture. A subtrochanteric fracture and a fracture of the stem were observed on radiographs, and a radiolucent line was observed in the proximal portion of the stem and a well-fixed distal portion was observed. Revision THA using a proximal femoral replacement stem and resection of the proximal femur has been proven as an effective procedure for treatment of an elderly patient with a fractured Lübeck stem with a well-fixed distal stem.
4.Comparative Study for Postoperative Initial Fixation Patterns of Two Different Types of Cementless Short Stem Using Three-Dimensional Templating Software
Takuya NAKAI ; Yu TAKEDA ; Saori NIITSU ; Yuki FUJIHARA ; Shohei OKAHISA ; Toshiya TACHIBANA ; Shigeo FUKUNISHI
Clinics in Orthopedic Surgery 2024;16(1):23-33
Background:
While cementless short stems have become popular in total hip arthroplasty (THA), Metha is a relatively recent development that differs from other short stems in its initial fixation concept of partial collum-sparing metaphyseal anchorage. The purpose of this study was to quantify the contact state between Metha and the femur. Additionally, we investigated the difference in contact points between Meta and Fitmore, which is one of the more popular curved short stems.
Methods:
We conducted a retrospective review of 42 hips that underwent THA using Metha and 41 hips using Fitmore. Stemto-femur contact was evaluated by density mapping using a three-dimensional digital template system to quantify the contact condition according to the modified Gruen zone. The criterion for the stem-to-bone contact boundary was defined as a computed tomography value of 543 Hounsfield.
Results:
Quantitative evaluation of Metha according to the modified Gruen zones showed the ratio of surface area with high cortical contact in each zone. The results were 4.6% ± 5.7% in zone 1, 0.9% ± 2.3% in zone 2, 19.1% ± 12.9% in zone 3, 1.4% ± 3.2% in zone 5, 29.6% ± 16.4% in zone 6, and 25.1% ± 17.7% in zones 7. Evaluation of Fitmore for the same zones was as follows: 1.6% ± 2.4%, 18.5% ± 16.9%, 20.8% ± 17.4%, 12.7% ± 12.8%, 3.7% ± 5.8%, and 13.3% ± 10.3%. Comparing the two groups, the contact area was significantly greater for Metha in zones 1, 6 and 7 and Fitmore in zones 2 and 5 (p < 0.05).
Conclusions
It is possible for Metha to achieve metaphyseal anchoring by contacting the cortical bone at the proximal femur, thus avoiding proximal offloading. To the best of our knowledge, no previous studies have quantitatively reported stem-to-cortical bone contact conditions in curved short stems.