APPLICATION OF CLINICAL SCORE FOR IMPLANT SELECTION IN THE TREATMENT OF SUB-CAPITAL FEMUR FRACTURES IN ELDERLY PATIENTS

Abstract

Background: Displaced sub-capital fractures of the femur are traditionally treated by hip arthroplasty (hemi or total joint replacement). Total hip arthroplasty (THA) was formerly disfavored due to presumed higher peri-operative complications, higher costs and higher incidence of dis-location. Lately, this procedure regained acceptance as a suitable solution for active elderly patients. The use of monopolar hemi-arthroplasty implants (Austin-Moore’s, Thompson’s and others) is losing favor due to high rates of hip pain caused by gradual stem subsidence and metallic head protrusion. The bipolar hemi arthroplasty is thought to lower the rates of hip-pain due to its modular cemented or cementless stem and the bi-articular bearing-surface. Numerous patient-oriented scores have been suggested; evaluating the old-patient’s pre-fracture function while predicting his/her post-operative demands. Such score should optimize the use of hip implants: reducing operative risks while improving long term function. Since the beginning of 2005 we have used a modification of a score suggested by Rogmark et al. (JBJS-A, 84:2002). We have evaluated the pre-fracture activity of patients sustaining displaced sub-capital femur fractures. The score contains 4 items: Mobility (with/without a cane vs. walker support or more). Residence (at home vs. a nursing home), Mental Status (preserved vs. confused) and age (less or over 80 years). Each item is scored 5 or 2 points. We have used this score for the selection of appropriate surgical procedure: an Austin-Moore hemi-arthroplasty (less than 15 points), a bipolar cementless hemi-arthroplasty (15–17 points) or a Total Hip Arthro-plasty (20 points).

Objectives: To evaluate the application of score, and accuracy of implant selection. To evaluate outcome of those cases where an improved implant was chosen.

Methods: All patients who sustained displaced sub-capital femur fracture during the 2005 were evaluated. We collected data of pre-fracture mental status, mobility, residence and other demographic data and re-calculated each patient’s score. Factors evaluated were: correct fulfillment of the modified score (use of correct implant), peri-operative complications, radiographic results (immediate and after 3 months), post-rehabilitation function and mortality within one year of surgery.

Results: During the 2005 we managed surgically 60 patients with displaced sub-capital femur fractures. There were 39 females (65%) and 21 males. Mean age was 82 (range 67–96) years. Two independently functional patients had total hip arthroplasty (1 female, 1 male aged 67, 69 years, Rogmark score 20 in both). Eighteen patients underwent implantation of cementless bipolar hemi-arthroplasty (11 females, 7 males, mean age 78 years mean Rogmark score 18.3). Forty patients had hemi-arthroplasty with an Austin-Moore prosthesis (29 females, 11 males, mean age 84 years, mean Rogmark score 13.7). The application of Rogmark recommendations proved accurate in 17q18 patients with bipolar prosthesis (1 patient was found to be not-eligible for this prosthesis) but in the Austin Moore implants only 33 of 40 (82%) patients were accurately selected to receive this implant while the other 7 patients should have received the bipolar implant. Total incorrect use of the score guidelines was 13%. Detailed review of cases where an improved prosthesis was implanted (THA and bipolar prostheses, 20 patients), revealed no case of dislocation, 1 case of late peri-prosthetic fracture, one case of deep infection, and one death during 1 year of follow-up. All patients were able to walk with a cane at 3 months.

Discussion: Selection of surgical procedure for displaced sub-capital femur fracture is a compromise between an improved hip implant (necessitating longer operative time & higher peri-operative risks) or a hemi-arthroplasty (with shorter operation & presumed lower peri-operative risks). The current study demonstrates the use of a tool for hip implant selection. Operating surgeons were tended to underscore patient’s function thus selecting the simple Austin-Moore implants in some of the patients who would have benefited from an improved implant. The group of patients who received bipolar or THA implants showed low rates of dislocation, and acceptable rates of other complications. The aforementioned score could serve as a guiding tool for other treatment aspects such as surgical risk and rehabilitation period.

Conclusion: We hereby present our experience in the use of a mental-functional score for the selection of hip implant for displaced sub-capital femur fractures in elderly patients. This score enabled us to estimate postoperative demands of patients and select the correct operative procedure and implant. We believe this score is applicable and useful in the Israeli medical system. It will limit the use of simple hemi-arthroplasty to those patients whose ambulatory needs are limited, while enabling patients with higher needs to receive improved implants.