Hemiarthroplasty of the Hip with and without Cement: A Randomized Clinical Trial

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1 577 COPYRIGHT Ó 2012 BY THE JOURNAL OF BONE AND JOINT SURGERY, INCORPORATED Hemiarthroplasty of the Hip with an without Cement: A Ranomize Clinical Trial Fraser Taylor, BSc, MBChB, FRACS, Mark Wright, MBChB, FRACS, an Mark Zhu, BHB Investigation performe at Aucklan City Hospital, Aucklan, New Zealan Backgroun: Controversy exists regaring the use of cement for hemiarthroplasty to treat a isplace subcapital femoral neck fracture in elerly patients. The primary hypothesis of this stuy was that use of cement woul provie better visual analog pain scores following this proceure in an elerly patient population. Methos: Elerly patients (at least seventy years of age) without severe cariopulmonary compromise who presente to one institution with a isplace subcapital femoral neck fracture were offere inclusion in the stuy. One hunre an sixty patients (mean age, eighty-five years) with an acute isplace femoral neck fracture were ranomly allocate to hemiarthroplasty with either a cemente Exeter or an uncemente Zweymüller Alloclassic component. Clinical an raiographic follow-up was performe for two years an the outcomes were recore by a bline assessor. The main clinical outcome measures were pain, mortality, mobility, complications, reoperations, an quality of life measure with use of valiate instruments. Results: The mean visual analog pain score at rest i not iffer significantly between the groups. The total number of complications was greater in the uncemente group (sixty-three compare with twenty-eight in the cemente group). Subsience was significantly more common in the uncemente group (eighteen compare with one in the cemente group). Intraoperative or postoperative fracture was also significantly more common in the uncemente group (eighteen compare with one in the cemente group). The mortality rate i not iffer significantly between the groups at any time point (thirty-five eaths in the uncemente group compare with thirty-two in the cemente group at two years). The Oxfor hip score was significantly poorer in the uncemente group at six weeks (38.8 compare with 35.7 in the cemente group), an it was also poorer or similar at later follow-up time points although the ifferences were not significant. There was also a tren towar poorer mobility an greater epenence on walking ais in the cemente group. The postoperative Short Musculoskeletal Function Assessment an Mini-Mental State Examination scores i not iffer significantly between the groups. Conclusions: In elerly patients (seventy years or oler) without severe cariopulmonary compromise who were treate with hemiarthroplasty for a isplace femoral neck fracture, use of a cemente Exeter implant an use of an uncemente Alloclassic implant provie a comparable outcome with regar to pain. However, implant-relate complication rates were significantly lower in the group treate with a cemente implant. Trens towar better function an better mobility in the cemente group were observe. These trens reache significance in particular functional scores at some postoperative time points. Level of Evience: Therapeutic Level II. See Instructions for Authors for a complete escription of levels of evience. Disclosure: One or more of the authors receive payments or services, either irectly or inirectly (i.e., via his or her institution), from a thir party in support of an aspect of this work. None of the authors, or their institution(s), have ha any financial relationship, in the thirtysix months prior to submission of this work, with any entity in the biomeical arena that coul be perceive to influence or have the potential to influence what is written in this work. Also, no author has ha any other relationships, or has engage in any other activities, that coul be perceive to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitte by authors are always provie with the online version of the article. A commentary by Timothy Bhattacharyya, MD, is linke to the online version of this article at jbjs.org. J Bone Joint Surg Am. 2012;94:

2 578 Hemiarthroplasty is the recognize treatment for isplace subcapital femoral neck fractures in elerly patients 1,2. However, controversy still exists regaring whether cemente or uncemente implant fixation is preferable in this patient population. Evience suggests that cementing prevents loosening by improving prosthesis anchorage to the bone 3. This is an avantage since a loose prosthesis can cause pain, elay patient mobilization, an require further surgery 4. However, the use of cement can complicate revision surgery an has been reporte to cause rare but severe cariovascular complications. Several past stuies on this topic were summarize in a 2010 Cochrane Systematic Review 3. These stuies were criticize for their size, inclusion criteria, poor ranomization, limite reporting of outcomes, inaequate follow-up, an exclusion of patients. The Cochrane review conclue that patients with cemente prostheses experience less pain at one year or later an ha improve postoperative mobility. Furthermore, no ifferences in mortality or complications between the groups were foun at any time point. The authors of the review acknowlege that the majority of the inclue stuies evaluate traitional prostheses such as the cemente Thompson an uncemente Austin Moore prostheses. Thus, espite its conclusion in favor of cementing, the review raise the nee for further comparisons between cemente prostheses an more avance uncemente prostheses. The results of recent stuies involving hyroxyapatitecoate uncemente prostheses suggest that these implants can achieve the same functional outcome as cemente prostheses 5. Unfortunately, those stuies i not present the results of raiographic follow-up. Given the cognitive challenges that are often face by members of this patient group, raiographic analysis is a useful tool for assessing the prosthesis performance 6. The present bline, ranomize controlle trial compare two well-ocumente an relatively moern unipolar esigns, cemente Exeter implants (Stryker Orthopaeics, Mahwah, New Jersey) an uncemente Zweymüller Alloclassic implants (Centerpulse, Zurich, Switzerlan). The aim of the stuy was to gather clinically meaningful ata on the relative merits an shortcomings of cementing of hemiarthroplasty implants. The primary hypothesis of this stuy was that use of a cemente hemiarthroplasty component woul provie an improvement in the visual analog pain score compare with use of an uncemente component in an elerly patient population. Materials an Methos This ranomize controlle trial inclue 160 patients with an acute isplace femoral neck fracture (Garen 7 stage III or IV) an was registere with the Australian New Zealan Clinical Trials Registry. All patients presente to Aucklan City Hospital between May 2006 an November The inclusion criteria were an age of at least seventy years an an acutely isplace fracture eeme by the amitting surgeon to be suitable for hemiarthroplasty. Patients with a previous fracture of the same hip or with a pathological fracture were exclue. In aition, one patient eeme by the amitting surgeon to be suitable for total hip arthroplasty was exclue. The suitability of each patient for receiving a cemente component was assesse bythecharge anesthetist,an patients whose risk of mortality was eeme unacceptable were exclue from the stuy. As there are no establishe criteria for the risk of mortality ue to implantation of cemente components, the assessment was base on the patient s age, preexisting cariovascular or respiratory isease, an/ or a history of bone cement implantation synrome 8. One hunre an sixty of the 301 patients who receive hemiarthroplasty uring the stuy perio were inclue in the trial (Fig. 1). All patients gave informe consent, an the research protocol was approve by the Northern Regional Ethics Committee an the Aucklan Hospital Ethics Committee. The patients were ranomize with use of a computer-generate, sequentially numbere, seale an opaque envelope. The envelope was opene in the operating room. Patients ranomize to the cemente group receive a moular Exeter stem with an appropriately size UniTrax hea (Stryker). The cementing technique was stanarize an involve use of a cement restrictor, lavage of the intrameullary canal, an retrograe introuction of the cement with use of a cement gun; the cement was not further pressurize after insertion. Patients ranomize to the uncemente group receive an uncemente Alloclassic stem with an appropriately size hea. The implant was inserte accoring to the manufacturer s instructions, an a template was use preoperatively to etermine the level of the femoral neck osteotomy. Care was taken to ensure that the femoral entry point was lateralize to avoi varus malpositioning. A box chisel was use to gain entry to the femoral canal, a canal finer was use to efine the femoral canal, an progressive rasping was use to prepare the canal for the efinitive component. Once the pitch of the impactor change from low to high, confirming contact with the cortical bone, a final rasp corresponing to the implant size was use. The efinitive implant was then inserte an its stability was confirme. The group allocation was reveale to the stuy coorinator (M.W.) immeiately after the operation. Efforts were mae to stanarize the proceures. The anesthetist, who was not bline to the type of hemiarthroplasty performe, was given no specific instructions regaring flui management for patients in either group, an treatment of intraoperative hypotension was the responsibility of the anesthetist. Hemiarthroplasty was carrie out with use of the moifie Haringe surgical approach 9 with the patient in the lateral ecubitus position. All patients receive a ose of 1 g of cephazolin (Kefzol; Eli Lilly, Inianapolis, Iniana) intraoperatively an two further oses at eight an sixteen hours postoperatively unless a prerecore allergy existe. A raiograph was obtaine immeiately after the operation. Each patient receive routine observation, analgesia, an prophylaxis against eep venous thromboembolism. Patients in both groups were allowe to mobilize with full weight-bearing as tolerate. The majority of the patients (110 of 160, 69%) were female, an the mean age was 85.2 years (range, seventy to 99.4 years). Operations were performe uner the supervision of one of twelve consultant surgeons experience with both proceures. The majority of proceures were performe by registrars in training. The mean uration of surgery was 4.5 minutes shorter in the uncemente group than in the cemente group. The groups i not iffer significantly with regar to intraoperative bloo loss, uration of hospitalization, Charlson Comorbiity Inex 10, or American Society of Anesthesiologists (ASA) grae 11 (Table I). Clinical an raiographic examinations were performe at approximately six weeks, six months, twelve months, an twenty-four months postoperatively. All clinical variables were assesse by an unbiase observer (a research nurse who was not involve in the surgery or clinical ecisions an who was bline to the treatment group). Complications, the Mini-Mental State Examination (MMSE) score 12, the Time Up an Go (TUG) score 13, the use of walking ais, the Short Musculoskeletal Function Assessment (SMFA) score 14, a visual analog scale pain score 15, the Oxfor hip score 16, an the ability to live inepenently were recore at each follow-up visit. Pain, assesse with use of a visual analog scale, was the primary outcome measure in the stuy. The Oxfor hip score, a wiely use instrument that has been valiate in patients with osteoarthritis an in patients who have unergone hip replacement surgery, was utilize to assess clinical hip function. Use of the Oxfor hip score following hemiarthroplasty is less well ocumente, but this instrument was selecte in the absence of a more suitable measure. The Oxfor hip score was etermine with use of the original Oxfor questionnaire, in which a low

3 579 Fig. 1 The flow of patients through the stuy. The inclue patients receive either a cemente Exeter stem or an uncemente Zweymüller Alloclassic stem. score implies a better outcome 16. The TUG test is a valiate measure of mobility in which the patient is aske to rise from a seate position, walk aroun a cone place 5 m away, an return to the original seat. The SMFA questionnaire is erive from the original Musculoskeletal Function Assessment questionnaire an contains forty-six questions relate to the quality of life of the patient. A sample size of eighty in each group was require to give an 80% probability of etecting a significant ifference (p < 0.05) in the primary outcome measurement (the visual analog pain score) between the two groups. A total of 160 patients were therefore enrolle. In the outcome analysis, all patients who ha been inclue in the stuy receive the treatment to which they ha been ranomize, in accorance with the intention-to-treat principle. All complications relate to the hip were recore at each follow-up appointment. All relevant raiographs mae on or after the ate of amission were reviewe by two experience orthopaeic surgeons. Each immeiate postoperative raiograph was evaluate to ientify perioperative fractures an the varus/valgus angulation an size of the femoral implant. Implants that eviate by more than 3 from the anatomical axis of the femur were classifie as being in either varus or valgus. Filling of the femoral meullary canal was measure by means of a moification of the technique of Garcia-Cimbrelo et al. 17. The with of the implant relative to that of the canal was measure at the mile of the implant stem an at 3 cm from its istal tip, an the component was consiere to be unersize if the average of the two ratios was <0.8 (<80% filling of the canal). All subsequent raiographs were stuie for fractures an for implant subsience. Measurements were mae from the tip of the implant to the tip of the greater trochanter, an an implant was classifie as having subsie if it ha move in the caua irection by >5 mm 18. Patients who i not atten a follow-up visit were sent a stanarize letter thanking them for their participation an asking them to complete the visual analog pain score, SMFA, Oxfor hip score, an mobility assessment instruments. Statistical Methos Binary variables were analyze with use of the Fisher exact test, an continuous outcomes were analyze with use of the Stuent t test (two-taile). Survival an the uration of hospitalization were further analyze with use of the Kaplan- Meier metho. A p value of <0.05 was consiere significant for all analyses. Source of Funing Funing for this stuy was provie by the New Zealan Orthopaeic Association (NZOA) an the Wishbone Trust. Funing from the Accient Compensation Corporation (Wellington, New Zealan) was also use for the stuy. Results All patients receive the allocate treatment. In the uncemente group, one patient later unerwent revision to a cemente hemiarthroplasty, two later unerwent conversion to a total hip arthroplasty, an one later unerwent a Girlestone proceure because of an unresolve eep infection. In the cemente group, two patients later unerwent a Girlestone proceure because of a eep infection.

4 580 TABLE I Patient Demographics Baseline Data (N = 160) Cemente (N = 80) Uncemente (N = 80) Age* (yr) 85.3 (7) 85.1 (6.6) Left sie (no.) Female (no.) ASA grae* 2.95 (0.49) 2.99 (0.53) Charlson Comorbiity 5.95 (1.20) 5.98 (1.26) Inex* Duration of hospitalization* (ay) 27.2 (14.6) 26.5 (14.26) Operative time* (min) 79.3 (17.2) 74.7 (18.8) Intraoperative bloo loss* (ml) 254 (130.8) 251 (156.8) *The values are given as the mean, with the stanar eviation in parentheses. ASA = American Society of Anesthesiologists. Complications Five eaths occurre within forty-eight hours of surgery in each group. In the cemente group, one of these eaths was ue to acute renal failure, two were ue to a respiratory infection, an two were ue to generalize sepsis. In the uncemente group, one of these eaths was ue to cariovascular arrest, three were ue to a respiratory infection, an one was ue to sepsis. Intraoperative hypotension was not assesse but the total number of cariovascular complications was comparable in the two groups, with seven in the cemente group an six in the uncemente group. The rates of nonfatal respiratory, urinary tract, an woun infections were comparable in the two groups (Table II). Six intraoperative fractures occurre in the uncemente group compare with none in the cemente group; this ifference was significant. All of these fractures were ientifie intraoperatively an treate with cerclage wires. Twelve aitional fractures occurre postoperatively in the uncemente group; none of these require further surgery. Mortality i not iffer significantly between the groups at any follow-up time point. A large number of patients withrew prior to completing the stuy (Table III), but these TABLE II Complications Cemente (N = 80) Uncemente (N = 80) Complication No. %* No. %* P Value Cariovascular ( ) ( ) Respiratory infection ( ) 8 10 ( ) 1 Superficial or eep 4 5 ( ) ( ) woun infection Urinary tract infection ( ) ( ) 1 Subsience ( ) 18 (inclues fracture 22.5 ( ) <0.001 subsience) Postoperative fracture ( ) 12 (6 greater 15 ( ) trochanter fractures) Intraoperative fracture 0 0 (0-4.6) ( ) Reoperation ( ) 4 5 ( ) 0.50 Dislocation ( ) 0 0 (0-4.6) 0.50 Other 1 peroneal nerve palsy 1.3 ( ) 1 retroverte implant 1.3 ( ) 1 *Values are given as the percentage, with the 95% confience interval in percent in parentheses.

5 581 TABLE III Follow-up an Mortality Followe Withrawn Cemente Uncemente Die Time Point Cemente Uncemente Cemente Uncemente No. %* No. %* 6 weeks ( ) ( ) 6 months ( ) ( ) 1 year ( ) ( ) 2 years ( ) ( ) *Values are given as the percentage, with the 95% confience interval in percent in parentheses. patients were inclue in the mortality analysis. The reasons cite for withrawal were similar in the two groups; in many cases, the patient was not healthy enough to atten the followup visit. The total number of complications was greater in the uncemente group (sixty-three compare with twenty-eight in the cemente group). Raiographic Results In the uncemente group, seven implants were in varus an two were in valgus relative to the anatomical axis of the femur. In the cemente group, one implant was in varus an one was in valgus. As note, six intraoperative fractures occurre in the uncemente group compare with none in the cemente group. Subsequently, eighteen cases of loosening an subsience occurre in the uncemente group compare with one in the cemente group. Twelve postoperative fractures, incluing six fractures of the greater trochanter (Vancouver 19 type AG), were note in the uncemente group compare with one in the cemente group. One Vancouver type-b1 fracture occurre in the cemente group as a result of a ocumente fall; this patient was treate conservatively because of frailty. None of the fractures in the uncemente group were attributable to falls. Raiographically observe complications are summarize in Table II. Clinical Outcomes (See Appenix) Subjective outcomes inclue the visual analog pain score, SMFA, an Oxfor hip score. The mean visual analog pain score an the mean SMFA score were better in the cemente group than in the uncemente group at each follow-up time point, although none of the ifferences reache significance. The mean Oxfor hip score was significantly better in the cemente group than in the uncemente group at six weeks postoperatively (p < 0.05). The Oxfor hip score was also better or similar in the cemente group at later follow-up time points although the ifferences were not significant. Objective outcomes inclue the ability to flex the hip to 45 without pain, the Inepenence Grae, the use of walking ais, an the TUG test. The patients in the cemente group performe the TUG test significantly faster than the patients in the uncemente group at six months an one year postoperatively (p = 0.01 for both). A significantly greater proportion of the patients in the cemente group compare with patients in the uncemente group were able to flex the hip to 45 without pain at six weeks postoperatively (p = 0.007). No other significant ifferences in outcomes between the groups were observe. A ecline in inepenence was note in both groups at the time of hospital ischarge. At the time of amission, 50% of the patients allocate to receive a cemente prosthesis an 59% of those allocate to receive an uncemente prosthesis ha been living in their own home; this ecrease to 32% an 34%, respectively, on ischarge. Twenty-nine of the patients in the cemente group an twenty-eight of the patients in the uncemente group who ha not require private hospital-level care before the surgery were subsequently able to return to their previous level of inepenence. Discussion Previous stuies on the treatment of femoral neck fractures in the elerly have focuse on comparisons between the cemente Thompson an uncemente Austin Moore implants. However, these prostheses o not correspon well with the prostheses use in current clinical practice. The present stuy involve the cemente Exeter stem an the uncemente Alloclassic stem. Both of these implants have been proven to be effective in total hip arthroplasty 20,21. The primary rationale for avoiing the use of cement comes from previous stuies linking cementing to perioperative eath an the occurrence of pulmonary embolism 4, The exact mechanism responsible has not been establishe, but it is believe to be attributable to either irect cement toxicity or embolism of bone marrow contents. In our stuy, no eaths in either group were irectly attributable to embolism. Furthermore, the patients in the cemente group i not experience more cariopulmonary complications. Forty-six patients with cariovascular comorbiities were exclue from receiving a cemente implant, an thus from the stuy, by the anesthetist. This represents a weakness of our stuy, as we were unable to inclue all patients for ranomization. It is important to point out that the stuy i not have the statistical power to evaluate the potential averse health effects of cement. However, the lack of any significant ifference in complications or mortality reporte in the Cochrane review suggests that

6 582 the risk of cementing is minimal. The rate of intraoperative hypotension was not recore in the present stuy, an this may be of interest in future stuies on this topic. The broa eligibility criteria use in the present stuy i not exclue patients on the basis of mental status. Because of the age of the stuy cohort (mean, eighty-five years), a consierable proportion of the patients ha cognitive eficiencies (47.5% of the patients in each group, as inicate by the MMSE score). We i not wish to exclue these patients because they reflect the realities of treating femoral neck fractures in the community an their inclusion mae our conclusions more generally applicable. However, incluing these patients i introuce consierable ifficulties uring the follow-up perio. Because of patient eaths an withrawals, twenty-one patients in the cemente group an twenty-seven in the uncemente group complete the full two years of follow-up. Despite the efforts that were mae to keep the patients in the stuy, many were unable to continue because of marke eclines in health an mental capability. Withrawals can often cause bias if the trens over time in each group are analyze. However, the effect of withrawals on the results of our stuy will have been minimal because outcomes were compare between groups at each time point. To further investigate the effects of the withrawals on our results, we conucte a seconary analysis of the patients who ha a full two years of follow-up. No significant ifferences were foun between the outcomes in these patients an the outcomes in the entire stuy cohort. The methos use to evaluate functional outcomes inclue both subjective an objective measures. The Oxfor hip, SMFA, an visual analog pain scores are all subjective scores an epen greatly on the subject s perceptions of pain an recovery. Only one significant ifference in subjective functional outcomes between the groups was foun: the better Oxfor hip score in the cemente group at six weeks postoperatively. That ifference may inicate that patients in the cemente group regaine hip function faster than those in the uncemente group. The functional outcome scores were very similar to those of previous stuies. Our primary outcome measure, the visual analog pain score, i not iffer significantly between the groups. Similarly, in 2009, Figve et al. reporte no significant ifferences in pain an function between patients treate with cemente Spectron an uncemente Corail implants 25. A large stuy conucte by Parker et al. i inicate significantly better Charnley pain scores from three weeks to two years postoperatively in the group treate with a cemente Thompson prosthesis compare with the group treate with an uncemente Austin Moore prosthesis 3. However, the follow-up in that stuy was conucte by telephone only. The most relevant fining of our stuy was the substantial ifference between the groups in the rate of complications. In the two years after the inex proceure, eighteen patients in the uncemente Alloclassic group ha subsience relate to fracture compare with one in the cemente Exeter group. Many factors may have contribute to this large ifference, incluing the suitability of each implant for hemiarthroplasty, the familiarity of the operating surgeons with each implant, an the margin of error tolerate by each prosthesis. Our results suggest that, consiering fracture an subsience risk, the cemente Exeter implant is superior to the uncemente Alloclassic implant in our stuy population. This is especially important in hemiarthroplasty as reoperations are often unrealistic because of the age of the patients. Our followup was limite to two years an we ha a low revision rate at that time point. Supporters of uncemente components note the ease of revision of these components compare with cemente components, an we acknowlege that this is a consieration in implant choice for many surgeons. Few previous stuies evaluating hip hemiarthroplasty have inclue etaile raiographic analysis, so it is ifficult to evaluate their implant-relate complication rates. However, a stuy that examine the longevity of the Austin Moore implant in slightly younger patients showe an average subsience rate of 29% compare with 22.5% in our stuy, which use the same criteria for assessing the occurrence of subsience 26. Figve et al. also reporte an intraoperative fracture rate of 1.9% an a postoperative one-year fracture rate of 3.7% for the uncemente Corail implant 25 compare with 7.5% an 15% in the uncemente group in our stuy. They also reporte similar functional outcomes for the Corail implant compare with the cemente Spectron implant. This stuy, along with others, raises the possibility that hyroxyapatite-coate uncemente implants may result in better functional outcomes with fewer prosthesis-relate complications 5,27,28. In summary, hemiarthroplasty with the cemente Exeter implant provie a comparable outcome with regar to pain compare with hemiarthroplasty with the uncemente Alloclassic implant in our stuy of elerly patients with a isplace femoral neck fracture an without severe cariovascular compromise. However, the seconary outcomes in our stuy favore the cemente Exeter implant, although most ifferences were not significant. More importantly, there was a significant ifference in the rate of implant-relate complications in favor of the cemente proximal femoral hemiarthroplasty implants. Appenix A table showing the patient outcome scores at each time point is available with the online version of this article as a ata supplement at jbjs.org. n Fraser Taylor, BSc, MBChB, FRACS Mark Wright, MBChB, FRACS Aucklan City Hospital, Private Bag , Aucklan Mail Centre, Aucklan 1142, New Zealan. aress for F. Taylor: fj_taylor@hotmail.com Mark Zhu, BHB Aucklan School of Meicine, University of Aucklan, Private Bag , Aucklan Mail Centre, Aucklan 1142, New Zealan

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