Comparison of different types of artificial hip joints that may be used for treating fractures of the hip

Many different types of artificial hip joints (arthroplasties) may be used to treat hip fractures, which are breaks (fractures) in the thigh bone (femur) near the hip joint. Differences in these artificial joints include different shapes of the stem set into the bone; the incorporation of a secondary joint (bipolar joint); joints that replace only the ball part of the ball and socket hip joint (hemiarthroplasty) and those that also involve replacing the socket part of the hip joint (total hip replacement). In addition an arthroplasty may be of the press fit type or secured in place within the bone using a filler (bone cement).

Twenty-three trials involving 2861 older and mainly female patients with hip fractures are included in this review. The findings from the three main comparisons are summarised here. Six studies involving 899 participants compared a press fit arthroplasty with one that was secured in place with bone cement. Those joints that were cemented in place resulted in less pain and better mobility than those that were of the press fit type. Seven trials involving 857 participants compared those implants which have a second joint built into them (bipolar hemiarthroplasties) with those without this additional joint (unipolar hemiarthroplasties). No notable differences between these two types of implant were demonstrated. Seven studies of 734 participants compared different types of hemiarthroplasty with a total hip replacement. Most implants had been cemented in place. There was a trend to better functional outcomes after total hip replacement, but firm conclusions could not be made because of the lack of patient numbers.

There is good evidence that people with arthroplasties that are cemented in place have less pain and better mobility after the operation than those, which are inserted as a press fit. There is limited evidence that a total hip replacement leads to better functional outcome than a hemiarthroplasty.

Authors' conclusions: 

There is good evidence that cementing the prostheses in place will reduce post-operative pain and lead to better mobility. From the trials to date there is no evidence of any difference in outcome between bipolar and unipolar prosthesis. There is some evidence that a total hip replacement leads to better functional outcome than a hemiarthroplasty. Further well-conducted randomised trials are required.

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Background: 

Numerous types of arthroplasties may be used in the surgical treatment of a hip fracture (proximal femoral fracture). The main differences between the implants are in the design of the stems, whether the stem is cemented or uncemented, whether a second articulating joint is included within the prosthesis (bipolar prosthesis), or whether a partial (hemiarthroplasty) or total whole hip replacement is used.

Objectives: 

To review all randomised controlled trials comparing different arthroplasties for the treatment of hip fractures in adults.

Search strategy: 

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (September 2009), CENTRAL (The Cochrane Library 2009, Issue 3), MEDLINE, EMBASE and trial registers (all to September 2009), and reference lists of articles.

Selection criteria: 

All randomised and quasi-randomised controlled trials comparing different arthroplasties and their insertion with or without cement, for the treatment of hip fractures.

Data collection and analysis: 

Two review authors independently assessed trial quality, by use of a 10-item checklist, and extracted data.

Main results: 

Twenty-three trials involving 2861 older and mainly female patients with proximal femoral fractures are included. Cemented prostheses, when compared with uncemented prostheses (6 trials, 899 participants) were associated with a less pain at a year or later and improved mobility. No significant difference in surgical complications was found. One trial of 220 participants compared a hydroxyapatite coated hemiarthroplasty with a cemented prosthesis and reported no notable differences between the two prosthesis. Comparison of unipolar hemiarthroplasty with bipolar hemiarthroplasty (7 trials, 857 participants, 863 fractures) showed no significant differences between the two types of implant. Seven trials involving 734 participants compared hemiarthroplasty with a total hip replacement (THR). Most studies involved cemented implants. Dislocation of the prosthesis was more common with the THR but there was a general trend within these studies to better functional outcome scores for those treated with the THR.