|Year : 2019 | Volume
| Issue : 1 | Page : 60-68
Total hip arthroplasty in patients with Parkinson's disease
Colin T Penrose1, Abiram Bala2, Travis J Dekker1, Thorsten M Seyler1, Timmothy R Randell1, Cynthia L Green3, Samuel S Wellman1, Michael P Bolognesi1
1 Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina, USA
2 Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, California, USA
3 Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina, USA
|Date of Submission||12-Sep-2019|
|Date of Web Publication||28-Feb-2020|
Dr. Colin T Penrose
Department of Orthopaedic Surgery, Medical Center, Duke University, Durham, North Carolina
Source of Support: None, Conflict of Interest: None
Purpose of Study: The purpose of this study was to evaluate the incidence of dislocations, infections, revisions, and other medical and surgical complications in patients with Parkinson's disease (PD), who undergo total hip arthroplasty (THA) compared to a control group without PD.
Materials and Methods: Medicare patient data from 2005 to 2011 were retrospectively reviewed using the PearlDiver Technologies software (West Conshohocken, Pennsylvania, USA). Administrative coding and Boolean language were used to identify 6587 patients with PD diagnosed prior to THA and compared to a cohort containing all Medicare patients with a THA between 2005 and 2011 without any history of PD (767,991 patients). Statistical analysis was used to compare the number of patients with common comorbidities and medical and surgical complications. Systematical review of the literature on PD and THA was also performed.
Results: Patients with PD had a higher rate of medical complications, including pneumonia, urinary tract infection, and sepsis at 30 days postoperatively. At 90 days and final follow-up, they had a higher rate of postoperative complications including dislocation, prosthetic joint infection, and risk of revision.
Conclusion: PD is a progressive neurodegenerative disorder that affects the musculoskeletal system, and patients with PD often require surgical intervention for hip pain from a fracture, post-traumatic arthritis, or osteoarthritis. This study demonstrates the increased risk for several postoperative complications in patients with PD undergoing THA. It highlights the importance of an individualized risk-benefit analysis and multidisciplinary management before proceeding with arthroplasty for patients with PD.
Keywords: Arthroplasty, hip, joint dislocations, Parkinson disease, pneumonia, postoperative complications, replacement
|How to cite this article:|
Penrose CT, Bala A, Dekker TJ, Seyler TM, Randell TR, Green CL, Wellman SS, Bolognesi MP. Total hip arthroplasty in patients with Parkinson's disease. Duke Orthop J 2019;9:60-8
|How to cite this URL:|
Penrose CT, Bala A, Dekker TJ, Seyler TM, Randell TR, Green CL, Wellman SS, Bolognesi MP. Total hip arthroplasty in patients with Parkinson's disease. Duke Orthop J [serial online] 2019 [cited 2020 Apr 10];9:60-8. Available from: http://www.dukeorthojournal.com/text.asp?2019/9/1/60/279428
| Introduction|| |
Parkinson's disease (PD) is a progressive condition with loss of dopaminergic neurons in the substantia Nigra. It is the second-most common neurodegenerative condition, affecting approximately 1% of people 60 years and older in the United States. Musculoskeletal signs and symptoms include rest tremor, rigidity, impaired mobility, and bradykinesia. Despite pharmacotherapeutic advances with dopaminergic agents and novel therapies such as stem cell transplantation, the management of musculoskeletal manifestations remains a challenge. Patients with PD are thought to fall more often because of a shuffling gait, tremor, freezing (difficulty initiating or completing movement or maneuvering around obstacles), impairment of the righting reflex, and postural hypotension as a side effect of levodopa therapy. Johnell et al. demonstrated a significantly increased risk of hip fracture in PD patients compared to controls with odds ratios (OR) of 3.4 in men and 2.2 in women. Moreover, their data showed that within 10 years of being diagnosed with PD, 27% of patients had a new hip fracture. Another study showed similar results in the Nationwide Inpatient Sample, demonstrating that hip fractures occurred four times more often than predicted in patients with PD. This increased risk for fractures may be due to the previously mentioned increased fall risk and the fact that patients with PD are thought to be predisposed to osteoporosis from decreased physical activity, and Vitamin D deficiency from decreased UV exposure.,
Patients with PD also commonly have osteoarthritis. A French study demonstrated that 62% of PD patients had chronic pain and that this was attributed to osteoarthritis as the primary cause in 40% of patients. While the majority of patients with PD may undergo hemiarthroplasty for acute fracture, the results in the literature for this procedure have been mixed.,,, The use of THA for arthritis or fractures in patients with PD has been reported in small registry-based studies and case series.,,,,, Patients with PD are often cited as being at higher risk for multiple complications, including pneumonia, urinary tract infection (UTI), and dislocation. Recent review articles looking at a variety of neuromuscular conditions have concluded that THA is a viable option and may be beneficial for patients with PD but emphasize the importance of understanding the risks to make an informed decision., Overall, the role of THA for patients with PD is unclear, and investigations into outcomes in this patient cohort are limited.
The aim of this study was to evaluate the rate of postoperative complications in the full Medicare sample. The authors hypothesized that patients with PD would have a higher rate of perioperative and postoperative complications.
| Materials and Methods|| |
An exemption for this study was obtained from the institutional review board. Medicare patient data from January 1, 2005, to December 31, 2011, were reviewed using the PearlDiver Technologies database software, which provides anonymized results (West Conshohocken, Pennsylvania, USA). The database includes the Medicare Standard Analytical Files, which have 100% of inpatient and outpatient administratively coded facility data for all medicare patients. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis and procedure codes and Current Procedural Terminology codes (CPT) and Boolean language were used to identify patients who carried the diagnosis of primary PD (ICD-9-CM 332 or 332.0) prior to THA (ICD-9-CM procedure code 81.51 or CPT code 27130) [Figure 1].
|Figure 1:Study design flowchart for total hip arthroplasty in patients with and without Parkinson's Disease|
Click here to view
A cohort containing all Medicare patients who underwent THA between 2005 and 2011 without any history of PD was identified to serve as a control. We identified 6,587 patients in the Medicare database diagnosed with PD who subsequently underwent THA between January 1, 2005, and December 31, 2011. During this period, there were 767,991 patients who met the inclusion criteria for our control. The PD cohort had a more even distribution of males and females (P < 0.001). The PD cohort was older than the control P < 0.001. Both cohorts contained a small number of patients with unknown age and gender, and there was no statistically significant difference in the proportion of patients lacking this information between the cohorts (P = 0.08) [Table 1].
|Table 1: Demographic data for total hip arthroplasty in patients with Parkinson's disease and controls|
Click here to view
The number and proportion of patients in both cohorts with common comorbidities were identified using the Elixhauser measure, which has been validated for use in administrative databases. In order to be included, the comorbidity had to be diagnosed with an administrative code in the database prior to the admission in which the patient underwent THA. In addition to the standard Elixhauser comorbidities, smoking was added as an additional comorbidity using ICD-9-D-3051 and V1582. ICD-9-CM and CPT codes were used to identify medical and surgical complications of interest for THA. Medical complications assessed at 30 days included: myocardial infarction, congestive heart failure, arrhythmia, respiratory failure, deep vein thrombosis, pulmonary embolism, stroke, pneumonia, sepsis, acute renal failure, UTI, anemia, blood transfusion, bleeding complications, and cellulitis or seroma. Surgical complications included periprosthetic fracture or broken prosthetic joint, dislocation, periprosthetic infection, revision, and arthrotomy or incision and drainage. A complete list of ICD-9-CM and CPT codes corresponding to each diagnosis can be found in the [Appendix 1]. Both cohorts were analyzed for the occurrence of each complication within the first 30 days after THA for medical complications, and within the first 90 days and final follow-up after THA for surgical complications. Diagnoses from the same admission as the index surgery were included in each time point, consistent with postoperative complication metrics such as CMS Hospital Compare. When the output value was <11 but not 0, the program reports a “*” in order to comply with the Health Insurance Portability and Accountability Act and prevent tracing the data back to an individual patient. When this was encountered, the number was treated as a 5 to assume the median number.
Data are presented as counts and percentages of the total cohort. For each comorbidity and postoperative complication, the Chi-squared test was used to determine if there was a significant difference between the PD and control cohorts. In the one instance with an indeterminate value between 1 and 10, a value of 5 was assigned, and Fisher's exact test was used. In both cases, P < 0.05 was considered statistically significant. The OR and 95% confidence intervals (CIs) were also calculated for each comorbidity and postoperative complication. SAS version 9.4 (SAS Institute, Cary, North Carolina, USA) was used for these analyses and Forest plots of OR and CI were created using JMP Pro 11 (SAS Institute, Cary, North Carolina, USA).
We systematically reviewed the literature using PubMed with the initial search terms “PD” AND “total hip arthroplasty” (AND “total hip replacement”). Two of the authors screened the articles and their reference lists. The author, year published, number of patients, number of hips, and major findings were compiled in [Table 2].
| Results|| |
The PD cohort had a statistically significant higher rate of comorbidities, indicating this cohort was more medically complex compared to the control group. A side-by-side comparison with rates and statistical analysis is shown in [Table 3]. Overall, there was an increased rate in 30 out of 31 comorbidities analyzed, and with the univariate analysis, performed confounding variables are present.
|Table 3: Elixhauser comorbidities and smoking in patients with Parkinson's disease and controls|
Click here to view
Within the first 30 days when compared to the control, the PD cohort had an elevated rate of medical complications including myocardial infarction (OR 1.533, P < 0.001), congestive heart failure (OR 2.219, P < 0.001), arrhythmia (OR 1.389, P < 0.001), respiratory failure (OR 2.506, P < 0.001), DVT (OR 1.392, P < 0.001), PE (OR 1.312, P = 0.02), stroke (OR 2.419, P < 0.001), pneumonia (OR 3.071, P < 0.001), sepsis (OR 3.027, P < 0.001), acute renal failure (OR 1.839, P < 0.001), UTI (OR 2.166, P < 0.001), postoperative anemia (OR 1.286, P < 0.001), blood transfusion (OR 1.440, P < 0.001), bleeding complications (OR 1.684, P < 0.001), and seroma or cellulitis (OR 1.676, P < 0.001). These results are summarized in [Table 4] and [Figure 2].
|Figure 2: Forest plot of 30-day medical complications. MI: Myocardial infarction, DVT: Deep vein thrombosis, PE: Pulmonary embolism, PNA: Pneumonia, SIRS: Systemic inflammatory response syndrome. Complications in red have a statistically significant higher rate in Parkinson's disease patients than controls|
Click here to view
Surgical complications followed a similar trend with higher rates in the group with PD compared to the control cohort when assessed at the 90-day time point. The rates of periprosthetic fracture or broken prosthetic joint (OR 2.517, P < 0.001), prosthetic joint infection (OR 1.888, P < 0.001), dislocation of prosthetic joint (OR 2.626, P < 0.001), mechanical complications (OR 1.972, P < 0.001), THA revision (OR 2.027, P < 0.001), and arthrotomy or incision and drainage (OR 1.611, P < 0.001) were all elevated in the PD cohort compared to the cohort without PD. These results are reported in [Table 5]a and [Figure 3].
|Figure 3: Forest plot of 90-day surgical complications. Complications in red have a statistically significant higher rate in Parkinson's disease patients than controls|
Click here to view
In regards to the overall rate of surgical complications occurring at any time after total hip arthroplasty, the following results were significantly elevated: periprosthetic fracture or broken prosthetic joint (OR 1.779, P < 0.001), prosthetic joint infection (OR 1.468, P < 0.001), dislocation of prosthetic joint (OR 1.822, P < 0.001), mechanical complications (OR 1.434, P < 0.001), THA revision (OR 1.486, P < 0.001), and arthrotomy or incision and drainage (OR 1.406, P < 0.001). Osteolysis and polyethylene wear rates were similar between the cohort with PD and the control cohort (OR 0.700, P = 0.153). These results are summarized in [Table 5]b and [Figure 4].
|Figure 4: Forest plot of overall surgical complications. Complications in red have a statistically significant higher rate in Parkinson's disease patients than controls. Complications in black are not statistically significant as the 95% confidence interval overlaps the odds ratio of 1|
Click here to view
An NCBI PubMed database query returned 16 relevant results, and secondary searches yielded additional results. On review of these articles and cross-referencing citations of these articles, six,,,,,, were deemed appropriate for inclusion in the literature review and are summarized in [Table 2]. Review of these articles and two additional review articles, demonstrated a higher risk of the following in at least some studies: periprosthetic fracture, dislocation, UTI, pneumonia, and mortality. Conclusions regarding dislocation and prosthetic joint infection outcomes, in particular, have been inconsistent.
| Discussion|| |
The purpose of this study was to identify perioperative and postoperative complications associated with patients with PD undergoing THA. The authors demonstrated increased risk for both medical and surgical complications in this medically challenging patient cohort when compared to a control group. Previously published cohorts typically have been single institution or small national registries with contradictory results. This represents the largest published cohort to date.
The results of the present study suggest an elevated rate of revision surgery (6.62% compared to 4.55%), which is in contrast to two other studies that have reported no difference or even lower revision rates in patients with PD., However, the results of the present study appear similar to the PD series of Weber et al., which had 93% revision-free survival at 5 years. However, this series did include revision THA, which may undergo re-revision more often than primary THAs require revision. When they separately analyzed their elective primary THAs in PD patients, the revision-free survival at 5 years was 95%. It has been suggested that rates of revision-free survival in PD may overestimate true success in this population in particular, as patients with progressive or advanced PD may not be considered candidates for revision arthroplasty and may have higher mortality rates. In a nationwide registry study, only 34.7% of the PD patients were still alive 10 years after surgery. The rationale of surgical candidacy has been applied to suitability for revision total knee arthroplasty in patients with PD as well.
While the data presented here showed increased risks of dislocation, the reports in the literature are controversial on this diagnosis. Meek et al., showed decreased risk of dislocation with only 0.00–0.46 annual dislocation rates in the Scottish arthroplasty registry, while Jämsen et al. showed a 2-fold increased dislocation risk using the Finnish arthroplasty registry. Weber et al. presented a series with no dislocations in the primary elective THA group and Mathew et al. demonstrated similar results in a small cohort of THAs for fracture. While not directly generalizable to THA, rates of dislocation after hemiarthroplasty have been reported as high as 37%, and the authors recommended preferential treatment of femoral neck fractures with ORIF rather than hemiarthroplasty. More recently, a study of hemiarthroplasty in PD patients found 0 dislocations at 7.3 years mean follow-up of 49 patients. It has been proposed that as a result of improved medical management of PD symptoms, the risk of dislocation after hemiarthroplasty or THA is no longer elevated in patients with PD. While significant improvements in the treatment of PD have occurred, the present study would suggest that there remains an elevated risk of dislocation. Dislocations occurred in 5.56% of PD patients compared to 3.00% of controls. The reasons for this discrepancy in dislocation rates between the Scottish arthroplasty registry and the other studies (including this one) may involve the way patients were followed, the stage of their PD, or the state of the medical management of PD symptoms. In this study, any inpatient or outpatient visit with an associated ICD-9 code is recorded, so follow-up is likely to be very complete. Unfortunately, stage and medical management cannot be analyzed in registry studies.
The elevated rate of postoperative UTIs and pneumonia in the PD cohort is consistent with previous publications, which have demonstrated a 10% rate of pneumonia and a 20% rate of UTIs after hemiarthroplasty. Explanations for this tend to point to decreased physical reserves, poorer overall health status, and the difficulties patients with PD experience in caring for themselves. In addition, dopaminergic neuron death in key regions of the brain may cause urinary tract dysfunction and a loss of bladder control predisposing to infection. Efforts to optimize care and reduce the risks of such complications with extended duration of antibiotic prophylaxis, early mobilization, incentive spirometry, respiratory physiotherapy, and early discontinuation of Foley catheter are potential areas for improvement in patients with PD undergoing THA.
Patients with PD have been shown to have a higher infectious burden. However, previous studies have not found an elevated risk of surgical site infection,,, which is in contrast to the current study's data with a periprosthetic infection rate of 3.72% compared to 2.56% for controls (P < 0.001). This result may best be explained by the same arguments as other infectious complications discussed above. A study of total knee arthroplasty in patients with PD demonstrated an increased rate of deep infection at 6%, although this may not be generalizable to THA.
As a retrospective review of an established administrative claims database, the present study has inherent limitations. First, the postoperative complications we reviewed are all based on ICD-9 and CPT codes, which can be limited by the thoroughness of medical documentation as well as the experience of the administrative coding professional. However, administrative claims studies are validated in total joint arthroplasty, and for common comorbidities and complications the administrative record is typically accurate (specificity >92%) but can be incomplete. It is possible that patients with documentation of PD are more likely to have more thorough documentation in general, thus resulting in the appearance of higher rates of all complications and comorbidities. In addition to being older, the PD cohort is clearly medically more complex based on the higher rates of the Elixhauser comorbidities. With the present univariate analysis, this is a limitation of the conclusions that can be drawn from this study. However, it still remains useful for counseling patients due to the large control and PD cohort. The typical PD patient is older and more medically complex, and this study can be used for counseling them on their risk compared to the average THA patient.
Second, it is not possible to assess the stage of PD according to the Hoehn and Yahr classification of Columbia University. Patients with PD who suffer a hip fracture are more likely to have advanced-stage PD while surgeons are more likely to consider elective primary THA in patients with milder disease. Another limitation of this type of study is that it is not possible to assess pharmacologic management aimed at maintaining muscle tone and adherence to this medical management. Furthermore, administrative studies preclude analysis of some variables thought to impact complications including surgical approach and repair technique, component sizing,, and alignment. A randomized control trial or retrospective chart review with access to operative reports and radiographic findings would be better suited to analyze or control for these variables.
Third, there is an important limitation when cohort sizes are small. As previously mentioned, the system will not put out a non-zero value <11. Therefore, relatively rare complications in small cohorts will have a large margin of uncertainty. It is important to note that this occurred in only one instance. Despite these limitations, the large cohort size of 6,587 patients with PD diagnosed prior to THA will serve as a benchmark to compare outcomes of THA in patients with PD.
| Conclusion|| |
This large-scale administrative database study suggests patients with PD who undergo THA are at an increased risk for several surgery-related complications: dislocation, periprosthetic fracture, prosthetic joint infection, and revision or other reoperation. The increased risk for infectious complications, including sepsis, pneumonia, and UTIs highlights the need for multidisciplinary management of this challenging patient population. Studies have shown excellent pain relief and good short-term functional improvement with THA in patients with PD;,,,,, however, PD generally results in a progressive decline in function and present treatment modalities only slow this decline. Therefore, it is very important to weigh the increased risks of the surgical intervention with the potential benefits for patients with concomitant PD. In light of the results of this study, the authors recommend an individualized approach to patients with PD who present for THA. This approach should include pharmacologic treatment of the disease under the guidance of a neurologist, medical optimization of other comorbid conditions, and careful monitoring and precautionary measures to mitigate the risk of complications of total hip arthroplasty in patients with PD.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Dauer W, Przedborski S. Parkinson's disease: Mechanisms and models. Neuron 2003;39:889-909.
Adams RD. Principles of Neurology. 2nd
ed. New York: McGraw-Hill; 1981.
Zuckerman LM. Parkinson's disease and the orthopaedic patient. J Am Acad Orthop Surg 2009;17:48-55.
Riederer P, Gerlach M, Müller T, Reichmann H. Relating mode of action to clinical practice: Dopaminergic agents in Parkinson's disease. Parkinsonism Relat Disord 2007;13:466-79.
González C, Bonilla S, Flores AI, Cano E, Liste I. An update on human stem cell-based therapy in Parkinson's disease. Curr Stem Cell Res Ther 2016;11:561-8.
Cabanela ME, Weber M. Total hip arthroplasty in patients with neuromuscular disease. Instr Course Lect 2000;49:163-8.
Johnell O, Melton LJ 3rd
, Atkinson EJ, O'Fallon WM, Kurland LT. Fracture risk in patients with Parkinsonism: A population-based study in Olmsted county, Minnesota. Age Ageing 1992;21:32-8.
Bhattacharya RK, Dubinsky RM, Lai SM, Dubinsky H. Is there an increased risk of hip fracture in Parkinson's disease? A nationwide inpatient sample. Mov Disord 2012;27:1440-3.
Di Monaco M, Vallero F, Di Monaco R, Tappero R, Cavanna A. Bone mineral density in hip-fracture patients with Parkinson's disease: A case-control study. Arch Phys Med Rehabil 2006;87:1459-62.
Nègre-Pagès L, Regragui W, Bouhassira D, Grandjean H, Rascol O; DoPaMiP Study Group. Chronic pain in Parkinson's disease: The cross-sectional French doPaMiP survey. Mov Disord 2008;23:1361-9.
Staeheli JW, Frassica FJ, Sim FH. Prosthetic replacement of the femoral head for fracture of the femoral neck in patients who have Parkinson disease. J Bone Joint Surg Am 1988;70:565-8.
Clubb VJ, Clubb SE, Buckley S. Parkinson's disease patients who fracture their neck of femur: A review of outcome data. Injury 2006;37:929-34.
Coughlin L, Templeton J. Hip fractures in patients with Parkinson's disease. Clin Orthop Relat Res 1980;148:192-5.
Eventov I, Moreno M, Geller E, Tardiman R, Salama R. Hip fractures in patients with Parkinson's syndrome. J Trauma 1983;23:98-101.
Jämsen E, Puolakka T, Peltola M, Eskelinen A, Lehto MU. Surgical outcomes of primary hip and knee replacements in patients with Parkinson's disease: A nationwide registry-based case-controlled study. Bone Joint J 2014;96-B: 486-91.
Li J, Zheng W, Zhao J, Liu D, Xu W. Large diameter metal on metal total hip replacement for femoral neck fractures with neurological conditions: A retrospective assessment. Indian J Orthop 2014;48:605-11.
] [Full text]
Mathew PG, Sponer P, Kucera T, Grinac M, Knízek J. Total HIP arthroplasty in patients with Parkinson's disease. Acta Medica (Hradec Kralove) 2013;56:110-6.
Meek RM, Allan DB, McPhillips G, Kerr L, Howie CR. Epidemiology of dislocation after total hip arthroplasty. Clin Orthop Relat Res 2006;447:9-18.
Park KS, Seon JK, Lee KB, Yoon TR. Total hip arthroplasty using large-diameter metal-on-metal articulation in patients with neuromuscular weakness. J Arthroplasty 2014;29:797-801.
Weber M, Cabanela ME, Sim FH, Frassica FJ, Harmsen WS. Total hip replacement in patients with Parkinson's disease. Int Orthop 2002;26:66-8.
Kraay MJ, Bigach SD. The neuromuscularly challenged patient: Total hip replacement is now an option. Bone Joint J 2014;96-B: 27-31.
Queally JM, Abdulkarim A, Mulhall KJ. Total hip replacement in patients with neurological conditions. J Bone Joint Surg Br 2009;91:1267-73.
Elixhauser A, Steiner C, Harris DR, Coffey RM. Comorbidity measures for use with administrative data. Med Care 1998;36:8-27.
Quan H, Sundararajan V, Halfon P, Fong A, Burnand B, Luthi JC, et al.
Coding algorithms for defining comorbidities in ICD-9-CM and ICD-10 administrative data. Med Care 2005;43:1130-9.
Macaulay W, Geller JA, Brown AR, Cote LJ, Kiernan HA. Total knee arthroplasty and parkinson disease: Enhancing outcomes and avoiding complications. J Am Acad Orthop Surg 2010;18:687-94.
Winge K. Lower urinary tract dysfunction in patients with Parkinsonism and other neurodegenerative disorders. Handb Clin Neurol 2015;130:335-56.
Bu XL, Wang X, Xiang Y, Shen LL, Wang QH, Liu YH, et al.
The association between infectious burden and Parkinson's disease: A case-control study. Parkinsonism Relat Disord 2015;21:877-81.
Duffy GP, Trousdale RT. Total knee arthroplasty in patients with Parkinson's disease. J Arthroplasty 1996;11:899-904.
Bozic KJ, Bashyal RK, Anthony SG, Chiu V, Shulman B, Rubash HE. Is administratively coded comorbidity and complication data in total joint arthroplasty valid? Clin Orthop Relat Res 2013;471:201-5.
Hoehn MM, Yahr MD. Parkinsonism: Onset, progression and mortality. Neurology 1967;17:427-42.
Kwon MS, Kuskowski M, Mulhall KJ, Macaulay W, Brown TE, Saleh KJ. Does surgical approach affect total hip arthroplasty dislocation rates? Clin Orthop Relat Res 2006;447:34-8.
Garbuz DS, Masri BA, Duncan CP, Greidanus NV, Bohm ER, Petrak MJ, et al.
The Frank Stinchfield Award: Dislocation in revision THA: Do large heads (36 and 40 mm) result in reduced dislocation rates in a randomized clinical trial? Clin Orthop Relat Res 2012;470:351-6.
Howie DW, Holubowycz OT, Middleton R; Large Articulation Study Group. Large femoral heads decrease the incidence of dislocation after total hip arthroplasty: A randomized controlled trial. J Bone Joint Surg Am 2012;94:1095-102.
Daines BK, Dennis DA. The importance of acetabular component position in total hip arthroplasty. Orthop Clin North Am 2012;43:e23-34.
[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]