Abstract
Background
Modified anatomy of dysplastic hips, bone defects and previous operations make THA (total hip arthroplasty) in patients with hip dysplasia a technically challenging procedure.
Methods
One hundred and ten patients (mean 49.2 years of age, range 19–76, female:103, male:7) underwent 122 subsequent hip arthroplasties from 2012 to 2019. These patients were reviewed at least two years after THA. Plain radiography was used to determine Crowe classification of the affected hips. Fifty-three patients had an operation in childhood before THA was done (mean 47.0 years of age, standard deviation 8.3, range 19–62) and formed the “operated group”. Among these patients, there were Chiari pelvic osteotomies, periacetabular osteotomies, femoral osteotomies, greater trochanter distalizations and soft tissue operations. Fifty-seven were not operated in childhood (mean 52.3 years of age, standard deviation 10.9, range 19–76) and formed the “non operated group”. The functional status of the patients was assessed with the Oxford Hip Score (OHS).
Results
122 total hip arthroplasties were performed using uncemented femoral and acetabular components. There were 13 major complications identified. Ten were in the “operated group”, of which 5 needed revision surgery. Only 3 were in the “non operated group”, with no need for revision. Aseptic loosenings of the femoral component were seen in the patients that had femoral osteotomy done in childhood. Acetabular component migration and intrapelvic migration occurred due to the initial malposition and lack of osteointegration, thus requiring early revision after just 6 months. Other major complications were peroneal palsy, deep periprosthetic infection, severe trochanteritis and intraoperative femoral fracture. OHS was significantly higher in the “non operated group” 42.3 (10–48), opposed to 39.1 (10–48) in the “operated group” (p 0.017).
Conclusion
Corrective osteotomies in childhood are a risk factor for complications and lower medium-term survivorship of the THA in hip dysplasia patients.
Keywords: Hip dysplasia, Hip osteotomies, Total hip arthroplasty, Complications
1. Introduction
Osteoarthritis of the hip is the source of everyday pain which negatively impacts patient's daily living activities. Impaired overall function, leg shortening and limping add furthermore to the patient's burden that can be rather debilitating in the end-stage hip osteoarthritis.1 All mentioned difficulties are even more expressed in patients that develop osteoarthritis in the setting of hip dysplasia. Treatment strategy in childhood relies on placing and maintaining the femoral head in the acetabulum which facilitates normal further development.2 That is done by various joint preserving osteotomies on the proximal femur and pelvis.3 Nevertheless, treatment conducted in childhood or not, osteoarthritis can still develop.4 Patients tend to develop osteoarthritis at a younger age than those in the general population, with some marked anatomic differences.5 Specific anatomic features seen in hip dysplasia and altered biomechanics are all unfavourable and pose a challenge during subsequent operative treatment.3,6, 7, 8, 9 Total hip arthroplasty remains the gold standard as a reliable procedure that alleviates pain and restores the function of the patients. It is estimated that hip dysplasia comprises 2.6%–9.1% of total hip arthroplasties (THA) and is the main cause of THA in young people contributing with about 21%–29%.10,11 However, THA in hip dysplasia comes with a cost of increased perioperative complications and a somewhat lower functional outcome than in the general population.5 The aim of this paper is to report differences in complications following THA between hip dysplasia patients that had been operated in childhood and those that had not been operatively treated in childhood, as well as to show medium-term survivorship of the THA in that patients.
2. Materials and methods
The was a retrospective study performed using patients from a single Institution and operated by a single surgeon (author DD). Approval for the study was grantes by Ethics committee of the University Hospital Centre Zagreb (number: 02/013AG). All consecutive patients with hip dysplasia who underwent primary THA between January 2012 and January 2019 were included in the analysis. Patient demographic and other data were collected from patients charts. The study cohort included 110 patients who underwent 122 total hip arthroplasties. The study cohort was divided into 2 distinct subgroups based on the history of childhood operations on dysplastic hips. The inclusion criteria for the ″operated group“ were Chiari pelvic osteotomies, periacetabular osteotomies, proximal femoral osteotomies, and greater trochanter distalizations. Oxford Hip Score (OHS) as an outcome measure was taken and compared between groups at the final follow up.
2.1. Statistical analysis
Continuous variables are presented as mean with standard deviation. Comparison between the groups was made by Student's T test. Categorical variables are presented by means of descriptive statistic showing the number with percentage in the group, the difference between the groups were tested by chi square test. GraphPad Prism version 6 for Windows (GraphPad Software Inc., La Jolla, CA, USA) software was used for analysis and p-value < 0.05 was considered as statistically significant.
3. Results
3.1. Patient demographics
At the time of this review in January 2021 there were 103 females and 7 men with a mean age of 49.2 (range 19–76) (Table 1). Fifty-three patients with 60 hips fulfilled the criteria of an operation in childhood before THA was done (mean 47.0 years of age, SD 8.3, range 19–62). Fifty-seven patients with 62 hips were not operated in childhood and formed the other ″non-operated group” (mean 52.3 years of age, SD 10.9, range 19–76). ″Non-operated group” was slightly more than 5 years older at the time of the THA operation (p 0.003). Moreover, the difference was noticed regarding the proportion of men also. There were 11.3% of men in the ″non-operated group” in contrast to just 3.3% in the ″operated group”. Mean follow up was 69.4 months (range 25–109 months) in the ″operated group” whereas the follow up of the „non-operated“ group was 67.5 months (24–106 months).
Table 1.
Patient demographics.
| Characteristics | Non-operated group | Operated group |
|---|---|---|
|
Patients |
57 |
53 |
| Gender | ||
| Female | 51 | 51 |
| Male |
6 |
2 |
| Age (year) | ||
| Mean | 52.3 | 47.0 |
| Standard deviation | 10.9 | 8.3 |
| Range |
19–76 |
19–62 |
| Hips | 62 | 60 |
3.2. Radiographs
Plain radiography was used to determine preoperative Crowe classification of the affected hips. The radiological evaluation was based on anteroposterior and lateral radiographs. The analysis identified 14 Crowe 1, 22 Crowe 2, 19 Crowe 3 and 5 Crowe 4 hips in the ″operated group“ of patients (Fig. 1). The other group consisted of 20 Crowe 1, 17 Crowe 2, 12 Crowe 3 and 13 Crowe 4 hips (Fig. 2).
Fig. 1.
Anteroposterior radiograph of Crowe 3 hip that had a corrective osteotomy of proximal femur in childhood and postoperative anteroposterior radiograph demonstrating reconstruction with standard rectangular tapered femoral stem.
Fig. 2.
Anteroposterior radiograph demonstrating Crowe 3 hip in the ″non operated” group with subsequent reconstruction with the modular tapered fluted femoral component.
3.3. Operative technique
Modified Hardinge direct lateral approach, with the patients in the supine position, was used in all THAs. All were reconstructed with trabecular titanium acetabular component (Lima Delta TT, Lima International, Udine, Italy). Two different types of femoral components were used. The majority of hips, 110 of them, have been reconstructed with the standard rectangular tapered femoral stem (Lima C2, Lima International, Udine, Italy). Due to the very narrow femoral canal, 12 hips (5 in the operated group, 7 in non operated group) were reconstructed with the modular tapered fluted femoral component (Lima modulus system, Lima International, Udine, Italy).
3.4. Complications
There were 10 major complications noted in the “operated group”, and 3 in the “non operated group” (Table 2). In addition, there was no need for revision surgery in the „non-operated group”, whereas in the “operated group” revision surgery was conducted in 5 patients. Therefore, THA survivorship in the “non operated group” was 100% in the follow-up period of 67.5 months (range 24–106 months) making it a great medium-term result. The “operated group” had 92% survivorship of the THA in the follow-up period of 69.4 months (range 25–109 months). We found no revision surgeries in the subset of patients that have been reconstructed with the modular tapered fluted femoral component. Although severely modified femoral anatomy that rendered standard rectangular stems unfeasible is in no way favourable in the THA, that particular detail was probably offset by the versatility of the modular fluted stems that enabled the surgeon to make fine intraoperative adjustments, of anteversion angle and neck length and angle namely, and offered great intraoperative flexibility. We compared two different types of stems used but that difference in favour of femoral modular stem failed to reach statistical significance. Two peroneal palsies were identified in the “operated group” opposed to no neurological injury in the “non operated group”. One patient was a Crowe 3 male with a significant leg length discrepancy of 4 cm. We speculate that previous surgeries had generated adhesions and intratissue fibrosis that blocked sciatic nerve lengthening and therefore produced peroneal palsy. The other identified peroneal palsy occurred in a Crowe I female, but who was operated on multiple times in childhood thus creating significantly more adhesions and fibrosis. Intraoperative femoral fractures occurred in two patients, one in each group. The fractures happened during the implantation of the definite femoral component and were classified as Vancouver A fractures. Both were managed with the additional cabling without the need for revision stem or revision surgery. Revision surgery was needed in 5 patients, of which all of them were in the “operated group”. Three revision surgeries were caused by the early aseptic loosening of the femoral stems. One patient had revision due to the intrapelvic migration and protrusion of the acetabular component. One technical error took place and revision 2 weeks after the initial THA was conducted due to the dislocated polyethylene liner. In two patients with Crowe 4 (one from each group), because of the lacking bone stock, acetabulum was not reconstructable. Hemiarthroplasty with the bipolar femoral head was implanted in a patient in the “operated group”. The patient in the “non operated group” was not amenable to any reconstruction and ended with the Girdlestone procedure. One late periprosthetic infection was noted in the “non operated” group in an older male (76 years of age), but due to the patient's comorbidities revision was never done, and he was treated with prolonged antibiotic therapy.
Table 2.
Complications.
| Characteristic | Non-operated group | Operated group |
|---|---|---|
| Complications | 3 | 10 |
| Revisions | 0 | 5 |
| Aseptic loosening femoral component | 0 | 3 |
| Aseptic loosening acetabular component | 0 | 1 |
| Intraoperative femoral fracture | 1 | 1 |
| Inability to reconstruct acetabulum | 1 | 1 |
| Dislocated polyethylene insert | 0 | 1 |
| Peroneal palsy | 0 | 2 |
| Severe trochanteritis | 0 | 1 |
3.5. Clinical outcomes
The functional status of the patients was assessed with the OHS. OHS of the “non operated group” was 42.3 (10–48), opposed to 39.1 (10–48), in the “operated group” making it statistically significant (p 0.017). We report an OHS of 44.0 of the male population in the “operated” group and an OHS of 37.1 in the ″non operated group”. The opposite situation was noted in the females where the “non operated group” had better OHS outcome of 43.0 as to 38.5 in the “operated group”, also with statistical significance (p 0.003). Contrarily, in the “non operated group” females performed better probably because of the single most unsatisfactory male patient with the deep periprosthetic infection, who in addition, had the lowest overall OHS of just 10, thus strongly lowering the average male OHS of the group. Age-related OHS were almost equal in the “operated group”. Their young counterparts in the “non operated group” performed better but without statistical significance (p 0.217) with the OHS of 43.6. In the middle-aged subgroup, which was the most numerous subgroup, strong statistical significance occurred (p < 0.001) for the OHS of 44.6. The older adults subgroup, which had an OHS of 36.6, was outperformed by the ″operated group”. The reason is the same male patient (76 years of age) with deep periprosthetic infection. In the ″operated group”, OHS rises steadily, being 35.9 in the Crowe 1, 39.2 in the Crowe 2, 39.7 in the Crowe 3 and 40.4 in the Crowe 4. OHS outcomes in the “non operated group” were comparable throughout Crowe 1–3, with scores of 43.6, 45.8 and 44.3 respectively. Crowe 4 had by far the lowest score of 34.1, due to the aforementioned male patient with the deep periprosthetic infection that had a detrimental impact on the overall outcome.
4. Discussion
Straight and narrow femoral canals, increased anteversion of the femur, shortened leg, soft tissue contracture, shallow and retroverted acetabulum with general bone deficiency are all unfavourable anatomic factors in hip dysplasia.3,8,9 In this paper, we identified childhood corrective osteotomies as an independent factor that leads to an increased number of major perioperative complications. Our paper showed medium-term results of uncemented THA. A subset of patients that had been operated in childhood showed 92% of survivorship of their THA which is worse than in the general population with primary osteoarthritis but rather close to the data reported in the literature.12, 13 The other group of patients that had not been operated in childhood showed excellent medium-term results that match those for the general population with THA because of primary osteoarthritis. In addition, we showed significantly lower OHS after the THA in patients who had previously undergone pelvic or femoral osteotomy in comparison to those who had not been operated in childhood before the THA. This paper used Oxford Hip Score as a mean of patient reported outcome as seen in the literature.14,15 Neurologic injuries following THA are rare but potentially devastating complications since neurologic pain and a variable extent of muscle weakness can frustrate and diminish otherwise excellent clinical result.6,16 Both of the peroneal palsies identified in our study occurred in the “operated group”. The median age for THA in a patient with primary osteoarthritis in the UK is 68 years.17 Most of the patients with hip dysplasia need a THA between 40 and 59 years.17 In our study we noticed a paradox that patients that had previous surgery in childhood needed THA 5 years earlier than patients without previous hip surgery. Hip dysplasia patients that had previous childhood surgeries and now function normally, without the need of a THA, were not included in this study. But regardless of that, published data show that only 1/3 of hips after periacetabular osteotomy survives 30 years without signs of secondary osteoarthritis, especially if they are done at a younger age.4 Other 2/3 of patients show early signs of secondary osteoarthritis and need THA. Our findings demonstrate opposite results in contrast to some published papers found in the literature.6 Amanatullah et al.18 made a multicenter retrospective review of 22 patients with previous periacetabular osteotomies matched with 23 patients with hip dysplasia, but without previous surgeries. Their results show no difference in complication and revision rates and also no difference in Harris hip score between these two groups. Tokunga et al.19 compared 52 hips with prior pelvic osteotomy with 51 hips that had no previous surgery. Their results showed that prior pelvic osteotomy does not lead to a higher perioperative complication rate, higher revision rate, compromised Harris hip score, or shortened survivorship in eventual THA in developmental dysplasia of the hip. Shigemura et al.20 made a meta-analysis where they summarized clinical results of THA after previous pelvic osteotomy. They showed that previous pelvic osteotomy did not affect the results of the subsequent THA, except for smaller acetabular cup anteversion. Duncan et al.21 made a review article where they concluded that THA following previous pelvic and femoral osteotomy provides pain relief and improved function with similar complication rates, clinical outcomes, and survivorship compared to hips undergoing routine primary THA, but these procedures can be technically more demanding with increased operative times and intraoperative blood loss. The other group of published papers show the difference between these two groups, thus corroborating our results.22,23 A review article made by Gallazzi et al.24 demonstrated that THA after the femoral osteotomy is technically more demanding and may carry a higher risk of complications than one might expect after straightforward THA. Erdogan et al.25 compared 240 hips without previous pelvic or proximal femoral osteotomy with 118 hips that had previous preservation surgery. Their results showed an increased rate of complications, prolonged operative time, and an increased amount of blood loss. Although this paper suggests that previous corrective osteotomies of proximal femur and pelvis in childhood in hip dysplasia patients have a negative influence on major complications and survivorship of the THA, there are several limitations. Firstly, personally obtaining the data by ourselves in a retrospective manner limits the consistency of the data being analysed. Furthermore, the assessor of the data and the OHS was not blinded which can introduce bias. Also, the analysis utilised just OHS as clinical outcome score. Finally, baseline preoperative OHS was not made as this was a retrospective study. Because of that, we can not know the exact improvement that both groups made, and we can just assume that the groups were similar regarding their functional status. We are aware that can potentially be a source of an error. Our results and the main conclusion must be comprehended in light of these before mentioned limitations. However, we believe that reported results contribute to a better understanding of this particular topic.
5. Conclusion
Uncemented THA with the acetabular components made of trabecular titan showed excellent medium-term survival, even in the Crowe 3 and Crowe 4 hips. However, this study has shown that corrective osteotomies in childhood are a risk factor for complications during THA and a risk factor for lower medium-term survivorship of the THA. Careful planning of THA is of utmost significance to avoid and diminish complications and provide the best result for the patients.
Ethical committee approval taken
Financial Disclosures: This research did not receive any specific grant from funding agencies in the public, commercial or non profit sectors.
Ethics committee approval
Na 216. redovnoj sjednici Etičkog povjerenstva KBC-a Zagreb održanoj 9. svibnja 2022. godine razmotrena je Vaša zamolba za provodenje istraživanja pod nazivom: „Previous childhood operations are a risk factor for complications following total hip arthroplasty“ u svrhu izrade znanstvenog rada.
Istraživanje će se provesti u Klinici za ortopediju Kliničkog bolničkog centra Zagreb.
Etičko je povjerenstvo suglasno s provodenjem navedenog istraživanja, s obzirom da se isto ne kosi s etičkim načelima.
Author's contribution
KC: Conception and design of the work, data analysis and interpretation, drafting the article, critical revision of the article, final approval of the version to be published, ZS: Data collection, data analysis and interpretation, drafting the article, final approval of the version to be published, DD: Conception and design of the work, critical revision of the article, final approval of the version to be published.
Declaration of competing interest
The authors declare no conflict of interest.
Acknowledgment
We thank Tomislav Kelava,MD,PhD for assistance in the statistical analysis.
Contributor Information
Kresimir Crnogaca, Email: kcrnogac@gmail.com.
Zoran Sulje, Email: zoransulje@gmail.com.
Domagoj Delimar, Email: domagojdelimar@gmail.com.
References
- 1.Bijlsma J.W., Berenbaum F., Lafeber F.P. Osteoarthritis: an update with relevance for clinical practice. Lancet. 2011;377:2115–2126. doi: 10.1016/S0140-6736(11)60243-2. [DOI] [PubMed] [Google Scholar]
- 2.Dezateux C., Rosendahl K. Developmental dysplasia of the hip. Lancet. 2007;369:1541–1552. doi: 10.1016/S0140-6736(07)60710-7. [DOI] [PubMed] [Google Scholar]
- 3.Bicanic G., Barbaric K., Bohacek I., et al. Current concept in dysplastic hip arthroplasty: techniques for acetabular and femoral reconstruction. World J Orthoped. 2014;5:412–424. doi: 10.5312/wjo.v5.i4.412. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Lerch T.D., Steppacher S.D., Liechti E.F., et al. One-third of hips after periacetabular osteotomy survive 30 Years with good clinical results, No progression of arthritis, or conversion to THA. Clin Orthop Relat Res. 2017;475:1154–1168. doi: 10.1007/s11999-016-5169-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Greber E.M., Pelt C.E., Gililland J.M., et al. Challenges in total hip arthroplasty in the setting of developmental dysplasia of the hip. J Arthroplasty. 2017;32:S38–S44. doi: 10.1016/j.arth.2017.02.024. [DOI] [PubMed] [Google Scholar]
- 6.Shapira J., Annin S., Rosinsky P.J., et al. Total hip arthroplasty after pelvic osteotomy for acetabular dysplasia: a systematic review. J Orthop. 2021;25:112–119. doi: 10.1016/j.jor.2021.04.001. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Song J.H., Ahn T.S., Yoon P.W., et al. Reliability of the acetabular reconstruction technique using autogenous bone graft from resected femoral head in hip dysplasia: influence of the change of hip joint center on clinical outcome. J Orthop. 2017;14:438–444. doi: 10.1016/j.jor.2017.07.007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Ozan F., Uzun E., Gürbüz K., et al. Total hip arthroplasty in the developmental dysplasia of the hip using transverse subtrochanteric osteotomy. J Orthop. 2016;13:259–263. doi: 10.1016/j.jor.2016.06.010. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Vreim Holm A.G., Terjesen T., Reikerås O. Subtrochanteric shortening and uncemented arthroplasty in hips with high dislocation - a cohort study with 13-30 years follow-up. J Orthop. 2018;16:80–85. doi: 10.1016/j.jor.2018.12.005. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Thillemann T.M., Pedersen A.B., Johnsen S.P., et al. Danish Hip Arthroplasty Registry. Implant survival after primary total hip arthroplasty due to childhood hip disorders: results from the Danish Hip Arthroplasty Registry. Acta Orthop. 2008;79:769–776. doi: 10.1080/17453670810016830. [DOI] [PubMed] [Google Scholar]
- 11.Engesaeter L.B., Furnes O., Havelin L.I. Developmental dysplasia of the hip—good results of later total hip arthroplasty: 7135 primary total hip arthroplasties after developmental dysplasia of the hip compared with 59774 total hip arthroplasties in idiopathic coxarthrosis followed for 0 to 15 years in the Norwegian Arthroplasty Register. J Arthroplasty. 2008;23:235–240. doi: 10.1016/j.arth.2007.03.023. [DOI] [PubMed] [Google Scholar]
- 12.Chaudhry H., MacDonald S.J., Howard J.L., et al. Clinical outcomes and midterm survivorship of an uncemented primary total hip arthroplasty system. J Arthroplasty. 2020;35:1662–1666. doi: 10.1016/j.arth.2020.01.063. [DOI] [PubMed] [Google Scholar]
- 13.Streit M.R., Lehner B., Peitgen D.S., et al. What is the long-term (27- to 32-year) survivorship of an uncemented tapered titanium femoral component and survival in patients younger than 50 Years? Clin Orthop Relat Res. 2020;478:1283–1291. doi: 10.1097/CORR.0000000000001203. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Murray D.W., Fitzpatrick R., Rogers K., et al. The use of the Oxford hip and knee scores. J Bone Joint Surg Br. 2007;89:1010–1014. doi: 10.1302/0301-620X.89B8.19424. [DOI] [PubMed] [Google Scholar]
- 15.Kalairajah Y., Azurza K., Hulme C., et al. Health outcome measures in the evaluation of total hip arthroplasties--a comparison between the Harris hip score and the Oxford hip score. J Arthroplasty. 2005;20:1037–1041. doi: 10.1016/j.arth.2005.04.017. [DOI] [PubMed] [Google Scholar]
- 16.Park J.H., Hozack B., Kim P., et al. Common peroneal nerve palsy following total hip arthroplasty: prognostic factors for recovery. J Bone Joint Surg Am. 2013;95 doi: 10.2106/JBJS.L.00160. [DOI] [PubMed] [Google Scholar]
- 17.National Joint Registry for England, Wales, Northern Ireland and the Isle of Man: 15th Annual Report. 2019. [Google Scholar]
- 18.Amanatullah D.F., Stryker L., Schoenecker P., et al. Similar clinical outcomes for THAs with and without prior periacetabular osteotomy. Clin Orthop Relat Res. 2015;473:685–691. doi: 10.1007/s11999-014-4026-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Tokunaga K., Aslam N., Zdero R., et al. Effect of prior Salter or Chiari osteotomy on THA with developmental hip dysplasia. Clin Orthop Relat Res. 2011;469:237–243. doi: 10.1007/s11999-010-1375-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Shigemura T., Yamamoto Y., Murata Y., et al. Total hip arthroplasty after a previous pelvic osteotomy: a systematic review and meta-analysis. Orthop Traumatol Surg Res. 2018;104:455–463. doi: 10.1016/j.otsr.2018.03.002. [DOI] [PubMed] [Google Scholar]
- 21.Duncan S., Wingerter S., Keith A., et al. Does previous osteotomy compromise total hip arthroplasty? A systematic review. J Arthroplasty. 2015;30:79–85. doi: 10.1016/j.arth.2014.08.030. [DOI] [PubMed] [Google Scholar]
- 22.Marangoz S., Atilla B., Gök H., et al. Gait analysis in adults with severe hip dysplasia before and after total hip arthroplasty. Hip Int. 2010;20:466–472. doi: 10.1177/112070001002000409. [DOI] [PubMed] [Google Scholar]
- 23.Swarup I., Marshall A.C., Lee Y.Y., et al. Implant survival and patient-reported outcomes after total hip arthroplasty in young patients with developmental dysplasia of the hip. Hip Int. 2016;26:367–373. doi: 10.5301/hipint.5000354. [DOI] [PubMed] [Google Scholar]
- 24.Gallazzi E., Morelli I., Peretti G., et al. What is the impact of a previous femoral osteotomy on THA? A systematic review. Clin Orthop Relat Res. 2019;477:1176–1187. doi: 10.1097/CORR.0000000000000659. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Erdoğan F., Can A. The effect of previous pelvic or proximal femoral osteotomy on the outcomes of total hip arthroplasty in patients with dysplastic coxarthrosis. Acta Orthop Traumatol Turcica. 2020;54:74–82. doi: 10.5152/j.aott.2020.01.7. [DOI] [PMC free article] [PubMed] [Google Scholar]