title: Mid-term clinical results of primary total knee arthroplasty using metal block augmentation and stem extension in patients with rheumatoid arthritis.
abstract: BACKGROUND
  Despite recent advancements in rheumatoid arthritis (RA) pharmacotherapy, surgeons still encounter severely damaged knees. The purpose of the present study was to analyze the mid-term clinical results of total knee arthroplasty (TKA) with metal block augmentation and stem extension.
  
  
  METHODS
  A total of 26 knees in 21 patients who underwent primary TKA with metal block augmentation and stem extension were retrospectively reviewed. All patients with a mean age of 63 years had RA for a mean duration of 15 years. Functional and radiographic results as well as complications were evaluated at the mean follow-up period of 6 years after TKA. Eight knees were lost follow-up after the two-year evaluation.
  
  
  RESULTS
  Tibial bone defects with average depth of 19 mm were preoperatively recognized in all 26 knees. The postoperative joint line was reconstructed on average 11 mm above the fibular head using average thickness of 11 mm tibial inserts and 9 mm metal blocks with stem extension. Significant improvements (p < 0.05 for all comparisons) were observed postoperatively in maximum extension angle from -10° to -1°, range of motion from 101 ° to 115 °, and Knee Society Score (knee score/function score) from 35/18 to 90/64. Non-progressive radiolucent lines beneath the metal block and osteosclerotic changes around the medullary stem were found in 16 knees (62%) and 14 knees (54%), respectively. There was two failures (8%): fragile supracondylar femur fractures and knee instability. No knees showed any radiographic implant loosening, dislocation, polyethylene insert breakage, peroneal palsy, or infection.
  
  
  CONCLUSIONS
  Primary TKA with metal block augmentation and stem extension could effectively restore function in RA patients with advanced forms of knee joint destruction, and be reliable and durable for a mean postoperative period of 6 years. Further study is needed to determine the long-term results of TKA using metal block augmentation and stem extension.
authors: Department of Orthopaedic Surgery and Rheumatology, Clinical Research Institute, National Hospital Organization Kyushu Medical Center, 1-8-1 Jigyohama, Chuo-ku, Fukuoka, 810-8563, Japan. hamachan@ortho.med.kyushu-u.ac.jp.|Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. hamachan@ortho.med.kyushu-u.ac.jp.
authors: Satoshi
authors: S
authors: Hamai
authors: Department of Orthopaedic Surgery and Rheumatology, Clinical Research Institute, National Hospital Organization Kyushu Medical Center, 1-8-1 Jigyohama, Chuo-ku, Fukuoka, 810-8563, Japan. hmiya@qmed.hosp.go.jp.
authors: Hisaaki
authors: H
authors: Miyahara
authors: Department of Orthopaedic Surgery and Rheumatology, Clinical Research Institute, National Hospital Organization Kyushu Medical Center, 1-8-1 Jigyohama, Chuo-ku, Fukuoka, 810-8563, Japan. esaki-07@qmed.hosp.go.jp.
authors: Yukio
authors: Y
authors: Esaki
authors: Department of Orthopaedic Surgery and Rheumatology, Clinical Research Institute, National Hospital Organization Kyushu Medical Center, 1-8-1 Jigyohama, Chuo-ku, Fukuoka, 810-8563, Japan. hiratagoh@qmed.hosp.go.jp.
authors: Goh
authors: G
authors: Hirata
authors: Department of Orthopaedic Surgery and Rheumatology, Clinical Research Institute, National Hospital Organization Kyushu Medical Center, 1-8-1 Jigyohama, Chuo-ku, Fukuoka, 810-8563, Japan. kterada@qmed.hosp.go.jp.
authors: Kazumasa
authors: K
authors: Terada
authors: Department of Orthopaedic Surgery and Rheumatology, Clinical Research Institute, National Hospital Organization Kyushu Medical Center, 1-8-1 Jigyohama, Chuo-ku, Fukuoka, 810-8563, Japan. nobkob@qmed.hosp.go.jp.
authors: Nobuo
authors: N
authors: Kobara
authors: Department of Orthopaedic Surgery and Rheumatology, Clinical Research Institute, National Hospital Organization Kyushu Medical Center, 1-8-1 Jigyohama, Chuo-ku, Fukuoka, 810-8563, Japan. miyakiyo@qmed.hosp.go.jp.
authors: Kiyoshi
authors: K
authors: Miyazaki
authors: Department of Orthopaedic Surgery and Rheumatology, Clinical Research Institute, National Hospital Organization Kyushu Medical Center, 1-8-1 Jigyohama, Chuo-ku, Fukuoka, 810-8563, Japan. senjyu-manjyu@hotmailco.jp.
authors: Takahiro
authors: T
authors: Senju
authors: Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. seikei@ortho.med.kyushu-u.ac.jp.
authors: Yukihide
authors: Y
authors: Iwamoto
mesh_terms: D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000188:drug therapy / Q000601:surgery*; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation / Q000379:methods*; D016025:Bone Transplantation; D003131:Combined Modality Therapy; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D010026:Osteosclerosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery; D011859:Radiography; D016059:Range of Motion, Articular; D020127:Recovery of Function; D012189:Retrospective Studies; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery
chemical_list: D018501:Antirheumatic Agents