Complication Analysis of Conversion Hip Arthroplasty after Failed Intertrochanteric Fracture Fixation: A Meta-Analysis

Abstract

Background

Although internal fixation (IF) techniques for intertrochanteric fractures have continuously advanced, the failure rate remains around 5%, often requiring secondary surgical intervention. This meta-analysis aimed to evaluate the clinical outcomes of conversion hip arthroplasty (CHA) following IF failure in intertrochanteric fracture patients.

Methods

A total of 1,468 hips with CHA for failed IF of intertrochanteric fracture from 25 studies were included. The primary outcome was complication rate, including loosening, infection, dislocation, and periprosthetic fractures. The secondary outcomes were functional outcome measured by Harris Hip Score (HHS), operation time, and perioperative blood loss. A proportion meta-analysis using a random-effects model was performed to estimate the complications.

Results

The mean follow-up period of the included studies was 51.08 months. The overall complication rate was 17%. Among specific complications, the loosening and infection rates were both 3%, while the dislocation rate was 5%. The pooled incidence of periprosthetic fractures including intraoperative and postoperative fractures was 9%. The mean HHS was 84.19. The mean operation time was 150.24 minutes, and the mean perioperative blood loss was 918.39 mL.

Conclusions

CHA demonstrates an overall complication rate of 17%, which is slightly higher than that of primary hip arthroplasty, mainly reflecting the elevated risks of periprosthetic fractures and dislocation. Despite these concerns, CHA yields favorable functional recovery and represents an effective salvage strategy following failed IF, thereby supporting its continued role in clinical practice.

With the growing elderly population, osteoporotic hip fractures have become more prevalent, increasing the economic burden. Intertrochanteric fractures, the most common hip fractures in elderly patients, are primarily treated with internal fixation (IF), such as intramedullary nailing or dynamic hip screw fixation, as the preferred approach.¹⁾ Despite advancements in surgical techniques and instruments, fixation failure still occurs with reported rates ranging from 1.2% to 9.6%.²⁾

Conversion hip arthroplasty (CHA) is the standard salvage procedure for failed IF of intertrochanteric fractures, and the incidence of conversion to total hip arthroplasty (THA) following failed IF of intertrochanteric fracture fixation continues to rise.³,⁴,⁵⁾ However, this procedure is technically challenging due to altered anatomy such as severe bone loss with comminution, fracture deformity, and soft-tissue scarring, which may lead to higher complication rates, increased operation time, and severe blood loss.⁶,⁷⁾ Several studies have reported outcomes after CHA, but the wide variation in complication rates and functional outcomes creates uncertainty in clinical practice, making it challenging to provide consistent counseling. For instance, loosening rates range from 1% to 20%, and infection rates from 1% to 25%, depending on studies.⁸,⁹,¹⁰,¹¹⁾ Dislocation rates also vary significantly, with some studies reporting up to 16%, while others observed none.¹²,¹³⁾ Overall complication rates range from 5% to 73%, highlighting substantial variability in reported outcomes and the lack of standardized, consolidated statistical data for reliable clinical guidance.⁹,¹⁴⁾ This meta-analysis aims to synthesize the reliable evidence on CHA following failed IF of intertrochanteric fracture by evaluating complications, clinical outcomes, and surgical parameters.

METHODS

This study did not involve human participants or identifiable data; therefore, institutional review board approval and informed consent were not required.

Search Methods for the Identification of Studies

We conducted a comprehensive search of electronic databases to identify studies reporting the outcomes of CHA for failed intertrochanteric fracture fixation, covering the period from inception to November 2024. The search was performed following the updated guidelines of the Preferred Reporting Items for Systematic review and Meta-analyses Protocols (PRISMA-P) 2020 statement (Supplementary Material 1). The search encompassed multiple databases, including Medline (PubMed), Embase, and Cochrane Library, to ensure a broad and inclusive review of relevant literature. An overview of the search strategy on each website is detailed in Supplementary Material 2.

Criteria for Selecting Studies

All publications were classified using Endnote X20 for Windows. Two reviewers (NYK and BHY) autonomously reviewed all relevant titles and abstracts of studies and subsequently selected studies based on a full-text review. A third reviewer (KTP) settled discrepancies between these 2 reviewers. Inclusion criteria were as follows: a study (1) published as an original article in English, (2) involving either a comparative analysis or a single-cohort investigation that evaluated the outcomes of CHA for failed IF of intertrochanteric fractures, (3) reporting the primary outcomes (loosening, infection, dislocation, periprosthetic fractures, complications), and (4) with a minimum follow-up of 1 year.

Exclusion criteria were as follows: (1) not reporting the outcome of interest, (2) not reporting intertrochanteric fractures independently, (3) too specific arthroplasties, (4) too small sample size (< 10 patients), (5) use of national registry data, a review, expert opinion, case report, animal study, or basic science study.

Outcome Measures and Data Extraction

The primary outcomes of this meta-analysis were loosening, postoperative infection, dislocation, periprosthetic fractures, and overall complications. The secondary outcomes were functional outcome evaluated by the Harris Hip Score (HHS), operation time, and perioperative blood loss. For each eligible study, the 2 reviewers extracted and recorded the following data in a spreadsheet: the last name of the first author, publication year, enrollment period, study design, the number of hips, mean age at surgery, type of index implant (extramedullary fixation or intramedullary nail), number of loosening/postoperative infection/dislocation/periprosthetic fractures/overall complications/mean HHS mean operation time, and mean perioperative blood loss.

Quality Assessment and Publication Bias

Two authors (BHY and NYK) conducted separate evaluations of study quality using the Newcastle-Ottawa scales designed for observational studies. This tool includes 3 key parameters: selection, comparability, and outcome, each with subcategories. Selection can receive up to 4 stars, comparability up to 2 stars, and exposure or outcome up to 3 stars (Supplementary Material 3). We examined publication bias using Begg’s funnel plot and Egger’s test.

Data Analyses (Subgroup Analysis and Sensitivity Analysis)

The main analysis consisted of a proportion meta-analysis utilizing data from all pertinent studies that reported the occurrence of complications. Meta-analysis of proportions serves as a method to compute a comprehensive proportion from studies that report a single proportion. In our investigation, the proportion (p) was determined by dividing the number of hips developing complication occurrence by the total number of hips treated with CHA (n). Standard errors and confidence intervals for a single proportion were computed, and adjusted proportions were subsequently calculated through a logit transformation, as outlined below:

$$\text{Logit outcome}=\text{In}\frac{p}{1-p}$$

$$\text{Logit standard error}=\sqrt{\frac{1}{n\times p\times \left(1-p\right)}}$$

The heterogeneity between these groups was then computed. All hips with CHA were also divided according to index fixation: intramedullary nail and extramedullary fixation. Studies with 0 cells were supplemented by adding 0.5 successes to each arm.

Sensitivity Analysis

Removal of extramedullary fixation is expected to result in greater blood loss, longer operation times, and a higher incidence of postoperative fractures compared to intramedullary fixation. To explore this, we attempted a sensitivity analysis by examining studies based on the type of primary IF. However, due to the limited number of studies that detailed the fixation materials used prior to CHA, we were unable to perform a meaningful subgroup analysis. The use of cemented stems could also serve as an important covariate. However, studies utilizing cemented THA were scarce, which further limited our ability to assess this variable. The analyses were conducted using R Studio software version 4.4.2 (R Foundation for Statistical Computing). Since this study used published data, ethical approval is not required.

RESULTS

Description of the Included Studies

The primary search of the databases yielded 1,386 records. After duplicates were removed, 1,301 articles were screened by title and abstract. As a result, 92 full-text articleswere selected and reviewed for eligibility. A total of 42 articles were excluded. The reasons for exclusion were as follows: 20 studies did not report the outcomes of interest, 12 studies did not independently report intertrochanteric fractures, 8 studies reported on overly specific arthroplasties, 4 studies included fewer than 10 cases, and 3 studies were reviews or expert opinions. As a result, a total of 25 studies were finally included in the systematic review (Fig. 1).²,⁴,⁵,⁸,⁹,¹⁰,¹¹,¹²,¹³,¹⁴,¹⁵,¹⁶,¹⁷,¹⁸,¹⁹,²⁰,²¹,²²,²³,²⁴,²⁵,²⁶,²⁷,²⁸,²⁹⁾ Table 1²,⁴,⁵,⁸,⁹,¹⁰,¹¹,¹²,¹³,¹⁴,¹⁵,¹⁶,¹⁷,¹⁸,¹⁹,²⁰,²¹,²²,²³,²⁴,²⁵,²⁶,²⁷,²⁸,²⁹⁾ presents the key characteristics of the studies included in this meta-analysis, including enrollment periods, mean ages, mean follow-up durations, and the number of hips reported outcomes.

Fig. 1. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram detailing the selection process of relevant clinical studies.

Table 1. Outcomes Reported in Included Studies on Conversion Hip Arthroplasty after Failed Internal Fixation of Intertrochanteric Fractures.

First author (year)	Enrollment period	Mean age (yr)	Mean FU (mo)	No. of hips	Loosening	Infection	Dislocation	PFx	IFx	Complication	HHS (SD)	Operation time (SD, min)	Perioperative blood loss (mL)
Lee (2017)4)	2003–2015	74.1	36	33	0	0	0	1	5	6	NA	157.5	1,376.8
Zeng (2017)8)	2005–2014	76.9	48	142	1	4	4	14	NA	23	85.28	NA	NA
Zhang (2004)12)	1984–2001	72.2	88.8	19	0	NA	3	NA	7	10	79.8	176	1,378
Pui (2013)5)	1999–2009	64.8	36.3	91	1	3	2	3	4	13	83.6	NA	NA
Shi (2015)25)	2006–2012	72.4	47.5	31	0	0	2	NA	2	4	85.6	136	850
Min (2019)14)	1997–2016	62.1	42	44	0	NA	1	1	NA	2	79.8	NA	NA
Mortazavi (2012)13)	2000–2008	73.3	54	71	2	2	0	NA	3	7	NA	124	659
D'Arrigo (2010)16)	2004–2007	75.8	NA	21	0	1	0	NA	1	2	81	180	NA
Cho (2010)15)	1998–2008	70.5	40.3	18	NA	1	1	NA	4	6	82.1	203	NA
Tsai (2016)9)	1994–2011	73.8	75.6	79	16	4	7	17	14	58	77.6	122.8	691
Haidukewych (2003)18)	1985–1997	78	60	60	2	NA	1	NA	2	5	NA	240	1,125
Liu (2019)21)	2013–2016	70.3	26.2	18	0	0	0	0	1	1	91.08	100	550
Hung (2023)20)	2013–2019	73.6	NA	37	NA	4	5	NA	NA	9	NA	149.2	NA
Feng (2013)17)	2002–2009	76.5	31	13	NA	0	2	NA	1	3	83	124	631
Thalody (2024)27)	2014–2020	66.3	72.55	70	NA	1	0	3	4	8	NA	127	NA
Yu (2020)28)	2007–2017	66.84	65.2	198	18	0	6	13	NA	37	87.26	NA	NA
Yuan (2017)29)	2000–2010	77	60	111	1	4	1	4	6	16	72	NA	NA
Shi (2023)2)	2012–2019	75.6	51.9	54	3	1	2	1	5	12	81.8	133.9	587.2
Thakur (2011)26)	2000–2007	80.6	34.3	15	1	NA	0	NA	0	1	83.01	183	805
Qin (2019)24)	2007–2016	74	34.8	32	0	0	3	1	2	6	84.7	92	480
Morsi (2020)11)	2007–2013	66	88.8	107	0	1	2	0	2	5	89.3	96.7	345
Moon (2019)22)	2005–2015	69.1	73.2	37	0	0	3	NA	NA	3	89.1	195.5	786.5
Pachore (2013)23)	2008–2011	67.3	20.0	30	0	NA	0	NA	NA	0	70.60	NA	NA
Kulachote (2019)10)	2010–2017	73	NA	32	0	8	0	NA	3	11	NA	166	981
Huang (2025)19)	2012–2022	75	37.3	105	1	2	2	1	8	14	83.0	134.95	499.71

FU: follow-up, PFx: periprosthetic fracture, IFx: intraoperative fracture, HHS: Harris Hip Score, SD: standard deviation, NA: not available.

Postoperative Complications

Loosening was evaluated in 21 studies, with a pooled rate of 3% (95% CI, 2%–5%) based on proportion meta-analysis (Fig. 2A). Significant heterogeneity was observed among the studies included in the meta-analysis (I² = 64.3%, p < 0.0001). The pooled infection rate from 20 studies was 3% (95% CI, 2%–5%) (Fig. 2B), with significant heterogeneity (I² = 54.2%, p = 0.0021). All 25 studies included in this review reported dislocation, with a pooled rate of 5% (95% CI, 4%–6%) (Fig. 2C). There was moderate heterogeneity in the dislocation rates among the studies (I² = 34.5%, p = 0.0477).

Fig. 2. Each complication rate was calculated using proportion meta-analysis. (A) Loosening. (B) Infection. (C) Dislocation.

Periprosthetic fractures, encompassing both intraoperative and postoperative events, were assessed across 21 studies (Fig. 3A). The pooled incidence was 9% (95% CI, 7%–13%) based on a random-effects model. Substantial heterogeneity was observed among studies (I² = 66.7%, p < 0.01). The overall complication rate was 17% (95% CI, 12%–23%) (Fig. 3B).

Fig. 3. Each fracture rate was calculated using proportion meta-analysis. (A) Periprosthetic fracture. (B) Overall complication.

Harris Hip Score

While 19 studies in this review reported the mean HHS, only 11 included the standard deviation. In a weighted mean meta-analysis, the pooled HHS among included studies was 84.19 (95% CI, 81.66–86.73) (Fig. 4). This result indicates a “good” outcome, falling within the range of 80–89. In addition, the HHS meta-analysis revealed significant heterogeneity among the included studies (I² = 89.9%, p < 0.001).

Fig. 4. Mean Harris Hip Score was calculated for continuous variables. SD: standard deviation, MRAW: mean raw.

Operation Time/Perioperative Blood Loss

The mean and standard deviation of operation time were provided in 9 studies, showing a mean operation time of 150.24 minutes (95% CI, 131.60–168.87 minutes) (Fig. 5A). Of the 15 studies in this review that reported the mean perioperative blood loss, only 6 also provided the standard deviation. In a mean meta-analysis, the mean perioperative blood loss was 918.39 mL (95% CI, 521.09–1315.69 mL) (Fig. 5B). Despite the small number of included studies, both meta-analyses demonstrated significant heterogeneity.

Fig. 5. Effect sizes (weighted mean) were calculated for continuous variables. (A) Operation time. (B) Perioperative blood loss. SD: standard deviation, MRAW: mean raw.

Quality Assessment and Publication Bias

The Egger’s funnel plot was asymmetrical (Fig. 6). The p-values for publication bias were significant for infection and dislocation, whereas they were not significant for complications and the HHS. The funnel plot for operation time was symmetrical; however, the p-values for bias could not be assessed due to the limited number of studies.

Fig. 6. The Begg’s funnel plot and p-value by Egger’s test showing publication bias. The results were symmetrical, with no significant publication bias detected. (A) Infection rate. (B) Dislocation rate. (C) Periprosthetic fracture rate. (D) Overall complication rate. (E) Harris Hip Score. (F) Operation time.

DISCUSSION

Failed IF is expected to occur in patients with severe comorbidities. Comprehensive counseling with caregivers about surgical outcomes and potential complications is crucial, as they hope it will be their last procedure. While a few meta-analyses have reported complications of CHA after failed intertrochanteric fracture fixation, this study is the first to estimate the pooled complication rates by integrating data from existing studies.

The treatment of failed IF for intertrochanteric fractures remains a significant challenge due to factors such as limb shortening, deformity, excessive bone loss, and comminution resulting from the failed operation.³⁰,³¹⁾ Before proceeding with CHA, failed IF implants must be removed, and nonunion fragments must be mobilized. Additionally, severe osteoporosis and patient comorbidities further increase the risk of prosthesis-related complications including prosthesis subsidence, periprosthetic fractures, dislocation, and periprosthetic joint infection, which are significantly more common in CHA compared to primary hip arthroplasty.³²⁾

Implant loosening is particularly devastating, as it often leads to pain, functional decline, and the need for additional revision surgery.³³⁾ In our meta-analysis, the loosening rate was found to be 3%. It is comparable to the previously reported range of 1.3% to 4.9% for primary hip arthroplasty in intertrochanteric fractures.³⁴,³⁵⁾ To reduce this risk, surgeons carefully develop a surgical plan, with a strong emphasis on the selection of an appropriate femoral prosthesis. The use of long stems, in particular, increases the contact area with the medullary cavity and facilitates the bridging of preexisting defects and cortical perforations, thereby improving stability and reducing the risk of prosthetic loosening.²⁸⁾ However, there is currently no definitive evidence indicating that either standard or long femoral stems provide superior clinical outcomes.²,³⁶⁾

In cases of CHA for failed IF, periprosthetic fractures also represent a significant concern, as they commonly occur due to severe osteoporosis or stress risers from previous hardware. Our meta-analysis estimated a pooled periprosthetic fracture rate of 9%, which is higher than the range of 3.5% to 4.1% reported for primary THA, likely due to factors such as bone fragility, prior IF, and anatomical changes from previous fractures.³⁷,³⁸,³⁹⁾ Given that the reported incidence of periprosthetic fractures tends to increase with longer follow-up periods, the relatively lower incidence observed in our study may be attributed to the short-term follow-up.⁴⁰⁾ One study reported the use of a cemented stem significantly decreased the incidence of periprosthetic fractures (10.2% vs 3.0%, p = 0.041).²⁸⁾ Our study attempted to perform a subgroup analysis on this issue, but failed due to the limited number of studies categorized based on cement usage. Surgeons should be aware of potential complications related to cemented stems, such as prolonged operation time and stem subsidence due to cement creep. Additionally, cemented prosthesis syndrome, which poses a significant risk to patient survival, must be carefully considered.⁴¹,⁴²,⁴³⁾

The elevated risk of postoperative dislocation is known to be likely due to factors such as posterior bone loss and abductor weakness.⁶⁾ Reported dislocation rates vary, reaching up to 16%, and our meta-analysis estimated a pooled dislocation rate of 5%.¹²⁾ In primary hip arthroplasty, the dislocation rate has been reported to be 2.4% to 3.8%, which is slightly lower than the rate observed in our study.³⁵,⁴⁴,⁴⁵⁾ One Swedish hip arthroplasty registry study found that THA performed for sequelae of fracture had a higher revision rate due to dislocation than when done for other diagnoses (4.4% vs. 2.9%) at 7 years.⁴⁶⁾ Recently, efforts have been made to reduce the dislocation rate by utilizing dual-mobility cups, anterior and lateral approaches, and robot-assisted techniques.⁴⁷,⁴⁸,⁴⁹⁾ However, there is currently no long-term outcome data available to fully assess the impact of these interventions.

Our study demonstrated a non-inferior functional outcome with an estimated pooled HHS of 84.19. Studies have reported mean HHS ranging from 76.0 to 91.1 in patients who underwent primary arthroplasty for intertrochanteric fractures.²¹,⁴⁵,⁵⁰,⁵¹⁾ Although no consensus has been reached on the indications and timing of revision for failed IF, the delay of revision surgery in asymptomatic patients until symptoms appear may lead to poor functional outcomes.²⁸⁾ Patients who undergo CHA can eventually achieve similar functional outcomes to those of primary surgery, with successful postoperative rehabilitation. Therefore, revision CHA may be the preferred option for active patients who had failed IF.

Several limitations of this study should be acknowledged. First, most of the included studies were retrospective in design, which may have affected the overall quality of evidence and introduced potential selection bias. Second, there was considerable heterogeneity across studies in terms of the definitions and types of complications reported, as well as differences in follow-up duration and the classification of complications (e.g., perioperative vs. postoperative), making data pooling challenging. Third, many studies did not clearly differentiate between types of CHA (bipolar hemiarthroplasty or THA) or IF methods, limiting subgroup analyses. Finally, the reasons for conversion to THA were not consistently reported (e.g., nonunion vs. osteonecrosis), preventing outcome comparisons based on underlying indications.

In conclusion, we estimated the overall complications of CHA in patients with failed IF, highlighting the need for special attention to the risks of dislocation and periprosthetic fractures. Despite these concerns, CHA demonstrated favorable functional outcomes, underscoring its effectiveness in restoring mobility and improving quality of life. These factors should be emphasized during preoperative discussions with patients and caregivers to ensure informed decision-making and appropriate postoperative expectations.

SUPPLEMENTARY MATERIAL

Supplementary material is available in the electronic version of this paper at the CiOS website, www.ecios.org.

Supplementary Material 1

Updated checklist for Preferred Reporting Items for Sustematic review and Meta-analyses (PRISMA) 2020

Supplementary Material 2

The detailed search strategy for relevant clinical study selection

Supplementary Material 3

The Quality Assessment of Each Study According to the Newcastle-Ottawa Scales