Avoiding misclassification bias with the traditional Charnley classification: rationale for a fourth Charnley class BB

Röder, C; Staub, L P; Eichler, P; Widmer, M; Dietrich, D; Eggli, S; Müller, U (2006). Avoiding misclassification bias with the traditional Charnley classification: rationale for a fourth Charnley class BB. Journal of orthopaedic research, 24(9), pp. 1803-8. Hoboken, N.J.: Wiley 10.1002/jor.20224

Full text not available from this repository. (Request a copy)

Long-term follow up of patients with total hip arthroplasty (THA) revealed a marked deterioration of walking capacities in Charnley class B after postoperative year 4. We hypothesized that a specific group of patients, namely those with unilateral hip arthroplasty and an untreated but affected contralateral hip was responsible for this observation. Therefore, we conducted a study taking into consideration the two subclasses that make up Charnley class B: patients with unilateral THA and contralateral hip disease and patients with bilateral THA. A sample of 15,160 patients with 35,773 follow ups that were prospectively collected over 10 years was evaluated. The sample was categorized into four classes according to a new modified Charnley classification. Annual analyses of the proportion of patients with ambulation longer than 60 min were conducted. The traditionally labeled Charnley class B consists of two very different patient groups with respect to their walking capacities. Those with unilateral THA and contralateral hip disease have underaverage walking capacities and a deterioration of ambulation beginning 3 to 4 years after surgery. Those with bilateral THA have stable overaverage walking capacities similar to Charnley class A. An extension of the traditional Charnley classification is proposed, taking into account the two different patient groups in Charnley class B. The new fourth Charnley class consists of patients with bilateral THA and was labeled BB in order to express the presence of two artificial hip joints and to preserve the traditional classification A through C.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Pre-clinic Human Medicine > Institute for Evaluative Research into Orthopaedic Surgery
04 Faculty of Medicine > Department of Orthopaedic, Plastic and Hand Surgery (DOPH) > Clinic of Orthopaedic Surgery

UniBE Contributor:

Staub, Lukas, Widmer, Marcel, Eggli, Stefan, Müller, Urs (A)










Factscience Import

Date Deposited:

04 Oct 2013 14:46

Last Modified:

29 Mar 2023 23:32

Publisher DOI:


PubMed ID:


Web of Science ID:



https://boris.unibe.ch/id/eprint/19238 (FactScience: 1722)

Actions (login required)

Edit item Edit item
Provide Feedback