Cortical hypertrophy with a short, curved uncemented hip stem does not have any clinical impact during early follow-upReport as inadecuate

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BMC Musculoskeletal Disorders

, 16:371

First Online: 01 December 2015Received: 29 June 2014Accepted: 25 November 2015


BackgroundShort stems have become more and more popular for cementless total hip arthroplasty in the past few years. While conventional, uncemented straight stems for primary total hip arthroplasty THA have shown high survival rates in the long term, it is not known whether uncemented short stems represent a reasonable alternative. As cortical hypertrophy has been reported for short stems, the aim of this study was to determine the radiographic prevalence of cortical hypertrophy and to assess the clinical outcome of a frequently used short, curved hip stem.

MethodsWe retrospectively studied the clinical and radiographic results of our first 100 consecutive THAs 97 patients using the Fitmore® hip stem. Mean age at the time of index arthroplasty was 59 years range, 19 – 79 years. Clinical outcome and radiographic results were assessed with a minimum follow-up of 2 years, and Kaplan-Meier survivorship analysis was used to estimate survival for different endpoints.

ResultsAfter a mean follow-up of 3.3 years range, 2.0 – 4.4 years, two patients two hips had died, and three patients four hips were lost to follow-up. Kaplan-Meier analysis estimated a survival rate of 100 % at 3.8 years, with revision for any reason as the endpoint. No femoral component showed radiographic signs of loosening. No osteolysis was detected. Cortical hypertrophy was found in 50 hips 63 %, predominantly in Gruen zone 3 and 5. In the cortical hypertrophy group, two patients two hips; 4 % reported some thigh pain in combination with pain over the greater trochanter region during physical exercise UCLA Score 6 and 7. There was no significant difference concerning the clinical outcome between the cortical hypertrophy and no cortical hypertrophy group.

ConclusionsThe survival rate and both clinical and the radiographic outcome confirm the encouraging results for short, curved uncemented stems. Postoperative radiographs frequently displayed cortical hypertrophy but it had no significant effect on the clinical outcome in the early follow-up. Further clinical and radiographic follow-up is necessary to detect possible adverse, long-term, clinical effects of cortical hypertrophy.

KeywordsTotal hip arthroplasty Short stem prosthesis Fitmore® hip stem Survival rate Clinical outcome Radiographic analysis Cortical hypertrophy AbbreviationsBMDBone mineral density

DEXADual-energy absorptiometry

FEFinite element

HHSHarris Hip Score

RSARadiostereometric analysis

THATotal hip arthroplasty

UCLAUniversity of California, Los Angeles activity score

WOMACMcMaster Universities Osteoarthritis index questionnaire

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Author: Michael W. Maier - Marcus R. Streit - Moritz M. Innmann - Marlis Krüger - Jan Nadorf - J. Philippe Kretzer - Volker Ew


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