Total hip replacement for the treatment of femoral neck fractures. Long-term results

465 Total hip replacement for the treatment of femoral neck fractures. Long-term results Šarūnas Tarasevičius, Viktoras Jermolajevas 1, Rimantas Tarasevičius 2, Vidmantas Žegunis 2, Alfredas Smailys, Romas Jonas Kalesinskas Clinic of Orthopedics and Traumatology, Kaunas University of Medicine, 1 Department of Orthopedics and Traumatology, Klaipėda Regional Hospital, 2 Joint Replacement Center, Klaipėda Hospital, Lithuania Key words: femoral neck fractures, total hip replacement. Summary. Objective. To evaluate the outcome of total hip replacement after femoral neck fractures and analyze implant survival rates, complication rates, and mortality after surgery. Material and methods. We analyzed 135 primary hip replacements and 8 revision hip replacements performed in 1991 2003 years. Femoral neck fracture was the diagnosis for all primary hip replacements. All patients we analyzed prospectively: special form was filled in for every patient participating in the study. Personal data, operation data, revision date, diagnosis and complications were recorded. Personal patient s identification number was used to determine the death date if it was present, and it was checked if the patient was operated on in other orthopedic centers. Study ended up on 31 st of December, 2003. Results. Total cumulative implant survival rate was 92% and 94% for revision because of aseptic loosening 10 years postoperatively. Stem survival was 95% for revision because of aseptic loosening. Cup survival was 94% for revision because of aseptic loosening. Implant type had no influence on survival rates. Dislocation rate after hip replacement was 10%. Mortality was 25% at the end of the follow-up. Conclusions. Total hip replacement after femoral neck fracture showed high implant survival and low additional surgery rate. Total hip replacement after femoral neck fracture was associated with high dislocation rate. Low patient s mortality rate was associated with relatively lower mean patient s age. Introduction The incidence of hip fractures is increasing and the annual number worldwide is estimated to rise from 1.7 million in 1990 to 6.3 million by the year 2050 (1). Most hip fractures are related to osteoporosis (2). The cumulative risk for hip fracture is 20% for 80- year-old woman and almost 50% for 90-year-old woman (3). Femoral neck fractures in elderly patients can be devastating injuries that require medical and surgical treatment and consume considerable health care resources. The goal of treatment of these fractures is restoration of prefracture function without associated morbidity. The optimal treatment for displaced femoral neck fractures in elderly patients is a matter of controversy. Four surgical options are well supported in the orthopedic literature: reduction with internal fixation, unipolar hemiarthroplasty, bipolar hemiarthroplasty, and total hip arthroplasty. Internal fixation is associated with less operative trauma but later complications such as displacement of the fracture, nonunion and avascular necrosis may require revision (4, 5). This has led most surgeons to treat this fracture by arthroplasty, although internal fixation is still favored in few countries (Scandinavian and Lithuania also). However, total hip replacement for femoral neck fractures is associated with higher morbidity compared with internal fixation (6, 7). Primary hip replacement as a standard treatment of hip osteoarthritis was started in 1991 in Lithuania. The same year hip arthroplasty was started for the treatment of the femoral neck fractures either. The learning curve was an expected important impact factor for implant survival rates in our study. The aim of our study was to analyze the implant survival rates after total hip replacement for femoral neck fractures and assess mortality rates and postoperative complication rates after total hip replacement. Patients and methods All our data were obtained at our local hip arthro- Correspondence to Š. Tarasevičius, Clinic of Orthopedics and Traumatology, Kaunas University of Medicine, A. Mickevičiaus 9, 44307 Kaunas. E-mail: sarast@takas.lt

466 Šarūnas Tarasevičius, Viktoras Jermolajevas, Rimantas Tarasevičius et al plasty register at the department. All information was registered prospectively, but design of the study was retrospective. Surgical approach, implant, intraoperative and postoperative complications were recorded. The personal identification number was used to check if the patient was operated on in another hospitals. In case of patient s death, the death date was recorded. All patients were operated on with a posterolateral incision and posterior arthrotomy. Four orthopedic surgeons did all hip replacements. Femoral neck fracture was the preoperative diagnosis for all total hip replacements in this study. Both acute femoral neck fractures and nonunion after the femoral neck fracture were included. We analyzed 135 primary hip replacements and 8 revisions surgeries performed in 1991 2003 years. Eighty three (62.4%) women and 52 (37.6%) men underwent primary hip replacement. Patients mean age was 64,1 years (varied from 24 to 90 years). Five different cemented prosthesis types were used during this period. ScanHip Classic I and Classic II system was used in 95 (70.3%) cases, Aesculap Centrament prosthesis was implanted in 22 (16.3%) patients, Biomet Bimetric made from titanium alloy was used in 9 (6.7%) cases, Exeter hip was implanted in 8 (5.9%) patients, also for 1 patient Wlink Lubinus system was used. Implant failure, revision we defined as exchange of one or both prosthetic components (8). Twenty five percent of patients died before study ended up. All revision cases and patient death dates were recorded by December 31 st, 2003. Plot Statistic analysis The cumulative revision rate was calculated with Kaplan-Meier statistics (9). SPSS software was used. Cox regression was used to analyze patient s age, gender, and impact of learning curve on revision rates. Results At the end of the follow-up period 8 hips were revised (2 cups, 3 stems and 3 both components) of the 135 primary arthroplasties. The diagnosis for revision was aseptic loosening in 6 cases, recurrent dislocations in 2 cases. Only femoral component was exchanged in both recurrent dislocation cases. statistics for primary arthroplasties using revision arthroplasty as an end point showed implant survival rate of 92% after 10 years (Fig. 1). Total survival for aseptic loosening showed implant survival rate of 94% (Fig. 2). Stem survival for aseptic loosening showed implant survival rate of 95% (Fig. 3). Cup survival for aseptic loosening showed implant survival rate of 94% after 10 years (Fig. 4). Patients mortality rate was 4% one year post-operatively and 25% at the end of the follow-up (Fig. 5). We checked influence of age, prosthesis type, learning curve and sex for revision rate, and put these variables in Cox regression model. Cox regression analysis showed that odds ratio to be reoperated was 7 times higher for male compared with female, but this difference did not reach statistical significance (p=0.0887). Learning curve was found to be very Plot Fig.1. Kaplan Meier survival curve with confidence intervals (CI) to all hip arthroplasties and all revision Fig. 2. Kaplan Meier survival curve after hip arthroplasties and revisions because of aseptic loosening

Total hip replacement for the treatment of femoral neck fractures 467 Plot Plot Fig. 3. Kaplan Meier survival curve of the stem and revisions for aseptic loosening Fig. 4. Kaplan Meier survival curve of the cup and revisions for aseptic loosening Patient s survival 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Fig. 5. Patients mortality rate Table. Cox regression analysis Regresion Risk Independent Coefficient Ratio Prob Pseud Variable (B) Exp(B) Level R 2 Gender (F vs M) 1.928103 0.1454 0.0887 0.2336 Learning curve 893 0.9991 0.1468 0.1813 Implant type (Biomet Aesculap) 7.569228 5 0.9998 0 Implant type (Exeter Aesculap) 10.972653 10000+ 0.9995 0 Implant type (Wlink Aesculap) 8.039283 3 0.9999 0 Implant type (ScanHip Aesculap) 11.209447 10000+ 0.9995 0 Age 0.016559 1.0167 0.6728 0.0184

468 Šarūnas Tarasevičius, Viktoras Jermolajevas, Rimantas Tarasevičius et al flat and had no influence on revision rate. But B coefficient was not statistically significant and this should be interpreted with caution. The impact of implant type and patients age on the revision rates should not be interpreted because p values were too high. This Cox regression model defined influence of 43% on revision rate (Sum Pseudo R 2 is 43%). All Cox regression analysis is in Table. The dislocation rate was 10% (13 hips) within the first year after the surgery. Discussion It is still debated if prosthetic replacement of femoral head is accepted as optimum treatment for displaced femoral neck fractures. There are multiple studies with documented excellent results of total hip replacements in patients with osteoarthritis (10, 11). Several studies have shown improvement in function, pain, and mobility when results after total hip arthroplasty were compared with results after internal fixation or hemiarthroplasty in short term follow-up (12, 13). The large studies on displaced femoral neck fractures with two years follow-up have reported fracture-healing complications in the range of 35 50% (14). Our results show implant survival rates of 92% ten years after total hip replacement and these data correspond with reports of Swedish hip register (15). Mortality after the surgery was the main concern about total hip replacement after femoral neck fractures. M. J. Parker et al. reported mortality rate of 13% after total hip replacement and mortality rate of 20% after osteosynthesis in the patients between 70 79 years old within the first year after surgery. In the patients older than 90 year mortality was higher after total hip replacement 68% and 55%, respectively (16). As compared to the data from our series, patients mean age was 64.1 years and total mortality rate was 4% one year post operatively and 25% at the end of the follow-up. The possible reason for relatively high patients survival could be younger patient s age as compared to other studies. Other studies have failed to find any difference in mortality between fixation and arthroplasty, possibly because of selection of younger patients (17). The main complication after total hip replacement for femoral neck fractures is dislocation. A metaanalysis of orthopedic literature revealed median dislocation rate of 10.7% for total hip arthroplasty and it is 5 times higher as compared to osteoarthritis patients (18). Our results revealed dislocation rate of 10%; the same dislocation rate as reported in worldwide literature. Possible explanations might be: greater tendency to fall, less muscular control and increased ligament laxity, compared with osteoarthritis patients. A posterior approach was used for all patients in our study and it has been reported to be associated with a higher dislocation rate than an anterior approach (19). La Yao et al. cited four studies indicating better results after the anterior approach (4). The recommendation of anterior versus posterior surgical approach may be predicated better by surgeons familiarity and experience, and, perhaps, by results of studies analyzing pain and function in the early postoperative period. Conclusions Total hip replacement after femoral neck fracture showed high implant survival and low additional surgery rate. Total hip replacement after femoral neck fracture was associated with high dislocation rate. Low rate of patients mortality was associated with relatively younger mean patients age. Klubo sąnario endoprotezavimas gydant šlaunikaulio kaklo lūžius (vėlyvieji rezultatai) Šarūnas Tarasevičius, Viktoras Jermolajevas 1, Rimantas Tarasevičius 2, Vidmantas Žegunis 2, Alfredas Smailys, Romas Jonas Kalesinskas Kauno medicinos universiteto Ortopedijos ir traumatologijos klinika, 1 Klaipėdos apskrities ligoninės Ortopedijos ir traumatologijos skyrius, 2 Klaipėdos ligoninės Sąnarių implantacijos centras Raktažodžiai: šlaunikaulio kaklo lūžis, klubo sąnario endoprotezavimas. Santrauka. Darbo tikslas. Išanalizuoti šlaunikaulio kaklo lūžių gydymą atliekant klubo sąnario endoprotezavimą. Įvertinti implanto išgyvenimą, komplikacijų dažnį, mirtingumą po operacijos. Tyrimo medžiaga ir metodai. Išanalizuotos 135 pirminės klubo sąnario endoprotezavimo operacijos bei aštuonios pakartotinės, atliktos 1991 2003 metais. Visų pirminių klubo sąnario endoprotezavimo operacijų diagnozė iki operacijos šlaunikaulio kaklo lūžis. Duomenys rinkti perspektyviai. Kiekvienam operuotam

Total hip replacement for the treatment of femoral neck fractures 469 pacientui rašyta ligos istorija, kur registruoti asmeniniai duomenys, operacijos data, endoprotezo tipas, operacinė technika, pakartotinės operacijos (revizijos), jų priežastys, revizuotas implantas. Registruoti ligoniai, kuriems pakartotinai operuotas klubas. Užfiksuotos komplikacijos. Remiantis nacionalinio registro centro duomenimis, atrinkti visų buvusių pacientų mirties atvejai iki 2003 metų. Rezultatai. Bendras endoprotezo išgyvenimas per 12 metų po operacijos 92 ir 94 proc., kai pakartotinė operacija daryta dėl aseptinio implanto nestabilumo. Stiebo išgyvenimas 95 proc., gūžduobės 94 proc., kai pakartotinė operacija daryta dėl aseptinio implanto nestabilumo. Endoprotezo tipas išgyvenimo rezultatams įtakos neturėjo. Komplikacijos, kurių radosi po operacijos: endoprotezo išnirimas 10 proc. visų operuotų ligonių. Mirtingumas stebėjimo laikotarpiu po operacijos 25 proc. Išvados. Klubo sąnario endoprotezavimas, lūžus šlaunikaulio kaklui, patikimas gydymo metodas. Vėlesni gydymo rezultatai geri, mažai pakartotinių operacijų. Klubo sąnario endoprotezavimas, lūžus šlaunikaulio kaklui, susijęs su didesne endoprotezo išnirimo rizika. Nedidelis mirtingumas po operacijos susijęs su jaunu pacientų amžiumi. Adresas susirašinėti: Š. Tarasevičius, KMU Ortopedijos ir traumatologijos klinika, A. Mickevičiaus 9, 44307 Kaunas El. paštas: sarast@takas.lt References 1. Cooper C, Campion G, Melton LJ 3rd. Hip fractures in the elderly: a worldwide projection. Osteoporos Int 1992;2:285-9. 2. Cummings SR, Nevitt MC, Browner WS, et al. Risk factors for hip fractures in white women. Study of Osteoporotic Fractures Research Group. N Engl J Med 1995;332:767-73. 3. Zetterberg C, Elmerson S, Anderssson GP. Epidemiology of hip fractures in Goteborg, Sweden, 1940 1983. Clin Orthop 1984;191:43-52. 4. Lu-Yao GL, Keller RB, Littenberg B, Wennberg JE. Outcomes after displaced fractures of the femoral neck: a meta-analysis of one hundred and six published reports. J Bone Joint Surg (Am) 1994;76A:15-25. 5. Swiontkowski MF. Intracapsular fractures of the hip. J Bone Joint Surg (Am) 1994;76A:129-38. 6. Davison JNS, Calder SJ, Anderson GH, et al. Treatment of displaced intracapsular fracture of the proximal femur: a prospective, randomized trial in patients aged 65 to 79 years. J Bone Joint Surg (Br) 2001;83B:206-12. 7. Parker MJ, Khan RJ, Crawford J, Pryor GA. Hemiarthroplasty versus internal fixation for displaced intracapsular hip fractures in the elderly. A randomised trial of 455 patients. J Bone Joint Surg (Br) 2002;84(8):1150-5. 8. Malchau H, Herberts P, Garellick G, Soderman P, Eisler T. Prognosis of total hip replacement. Scientific exhibition presented on 69th AAOS meeting; 2002 Feb 13 17; Dallas, USA. 9. Dorey F, Amstutz C, Survivorship Analysis in the Evaluation of Joint Replacement. J Arthroplasty 1996;1(1):63-9. 10. Kesteris U, Robertsson O, Wingstrand H, Onnerfalt R. Cumulative revision rate with the Scan Hip Classic I total hip prosthesis. 1,660 cases followed for 2 12 years. Acta Orthop Scand 1998;69(2):133-7. Erratum in: Acta Orthop Scand 1998;69(3):330. 11. Wingstrand I, Persson BM, Wingstrand H. Total hip replacement with second generation cementing technique and the monobloc ScanHip: a 10-year follow-up. Int Orthop 2002; 26(2):69-7. 12. Bray TJ, Smith-Hoefer E, Hooper A, et al. The displaced femoral neck fracture: Internal fixation versus bipolar endoprosthesis. Results of prospective, randomized comparison. Clin Orthop 1988;230:127-40. 13. Gebhard JS, Amstutz HC, Zinar DM, et al. A comparison of total hip arthroplasty and hemiarthroplasty for treatment of acute fracture of the femoral neck. Clin Orthop 1992;282:123-31. 14. Tidemark J. The quality of life and femoral neck fractures Acta Orthop Scand 2003;74 Suppl 309:1-42. 15. Malchau H, Herberts P, Garellick G, Soderman P, Eisler. T Prognosis of Total Hip Replacement. Goteborg; 2002. 16. Parker MJ, Khan RJ, Crawford J, Pryor GA. Hemiarthroplasty versus internal fixation for displaced intracapsular hip fractures in the elderly. A randomised trial of 455 patients. J Bone Joint Surg Br 2002;84(8):1150-5. 17. van Vugt AB, Oosterwijk WM, Goris RJ. Predictive value of early scintimetry in intracapsular hip fractures. A prospective study with regard to femoral head necrosis, delayed union and non-union. Arch Orthop Trauma Surg 1993;113(1):33-8. 18. Iorio R, Healy WL, Lemos DW, Appleby D, Lucchesi CA, Saleh KJ. Displaced femoral neck fractures in the elderly: outcomes and cost effectiveness. Clin Orthop 2001;(383):229-42. 19. Hudson JI, Kenzora JE, Hebel JR, Gardner JF, Scherlis L, Epstein RS, Magaziner JS. Eight-year outcome associated with clinical options in the management of femoral neck fractures. Clin Orthop 1998;(348):59-66. Received 16 December 2004, accepted 17 May 2005 Straipsnis gautas 2004 12 16, priimtas 2005 05 17