Total hip revision with custom-made spacer and prosthesis: A case report

Abstract

BACKGROUND

Both periprosthetic joint infections (PJIs) and severe femoral segmental defects are catastrophic complications of total hip arthroplasty (THA), and both present a significant challenge in revisional surgery. There are limited data available to guide clinical decision making when both occur concurrently.

CASE SUMMARY

A 61-year-old woman presented with a 6-mo history of a sinus tract at the site of her original THA incision. Radiological imaging revealed a total hip joint implant with an ipsilateral segmental femoral defect. Based on histological, radiological, laboratory, and clinical features, a diagnosis of concurrent chronic PJI and segmental femoral defect (Type IIIB, Paprosky classification) was made. After multidisciplinary team discussion, three-dimensional (3D)-printed, custom-made antibiotic spacers were created that could be used to mold antibiotic-loaded cement spacer. These were placed following PJI debridement in the first stage of revision surgery. After the PJI was eliminated, a 3D-printed, custom-made, femoral prosthesis was created to repair the considerable femoral defect. After 20-mo follow-up, the patient had excellent functional outcomes with a near-normal range of hip movement. So far, neither evidence of recurrent infection nor loosening of the prosthesis has been observed.

CONCLUSION

We describe a case of “two-stage, custom-made” total hip revision to treat PJI with a concurrent segmental femoral defect. Use of a personalized, 3D-printed spacer and proximal femoral prosthesis led to satisfactory hip function and no early postoperative complications. Use of a customized implant provides surgeons with an alternative option for patients where no suitable spacer or implant is available. However, the long-term function, longevity, and cost-effectiveness of the use of custom-made prostheses have yet to be fully explored.

Key Words: Total hip arthroplasty; Joint revision; Prosthesis-related infections; Bone loss; Bone cement; Antibiotics; Case report

Core Tip: This paper reports a pioneering technique where a 3D-printed, custom-made antibiotic spacer and femoral prosthesis were used in revisional surgery for a challenging case of periprosthetic joint infection with a concurrent femoral segmental defect after total hip arthroplasty. A review of other relevant cases from the literature is presented, and the potential challenges and solutions of novel, personalized reconstructive methods are discussed.

INTRODUCTION

The safety and effectiveness of total hip arthroplasty (THA) have led to this being one of the most commonly performed operations worldwide, with more than 1 million hips replaced each year according to Organisation for Economic Co-operation and Development (OECD) data[1]. With the rise in the volume of primary THA performed, the total volume of revisional surgery (including complex re-revision) is projected to grow by 137% in the United States by 2030[2]. Infection and significant bone defects after THA are devastating and costly complications that are challenging to resolve. Here we present a rare case of two-stage revisional surgery for THA, in which both a 3D-printed, customized spacer and proximal femur prosthesis (PFP) were used to manage periprosthetic joint infection (PJI) with a concurrent segmental femoral defect.

CASE PRESENTATION

Chief complaints

A 61-year-old woman presented to our orthopaedic service with a 6-mo history of a non-healing ulcer and tract over the site of her original THA incision.

History of present illness

The patient reported low-grade fevers, particularly in the afternoons, and she had received several previous courses of antibiotics for deep infection at the wound site.

History of past illness

In September 2012, the patient had a severe car accident and was diagnosed with a left distal radius and ulna fracture (23r-E/4.2 and 23 μmol/L/3.1; ICD-10: S52.50 and S52.60), left acetabular fracture (62B3.1; ICD-10: S32.40), left femoral intertrochanteric and ipsilateral head fracture (31A2.3 & 31C1.3; ICD-10: S72.14 & S72.05), right-sided transverse process fracture at L1(ICD-10: S32.01), and multiple left-sided rib fractures (5-7th, 9th, 11th, ICD-10: S22.42). Internal fixation of the left proximal femoral fracture and ipsilateral femoral head fracture was performed, but later failed and she underwent total hip arthroplasty (THA) appropriately 6 mo after her initial injury. Four years after her primary THA, the patient had required a further open reduction of the replaced left hip due to another accident.

Personal and family history

No other relevant family history was reported

Physical examination

On examination, the patient had swelling over the left hip region, with mild pain on pressing the swollen area. The healed THA wound site was moist with pale secretions, and a deep leading sinus tract was identified.

Laboratory examinations

The patient’s haematological profile revealed a raised erythrocyte sedimentation rate (ESR, 74 mm/h; normal: 0-20 mm/h), and biochemistry demonstrated a raised level of C-reactive protein (CRP, 48.3 mg/L; normal: 0-8 mg/L). All other blood results were within normal limits. A swab test along the sinus tract grew an Enterococcus species on culture, which was consistent with the previous sinus tract examination

Imaging examinations

Plain radiography of the left hip in the anteroposterior plane demonstrated a post-THA hip with a severe proximal femoral defect (Figure 1).

Figure 1 X-ray film, anteroposterior plane. The left artificial hip had a severe proximal femoral defect.

FINAL DIAGNOSIS

The result of histological examination of a biopsy sample and bacterial cultures from the non-healing sinus tract over the incision site scar led to a diagnosis of PJI (ICD-10: T84.52), corroborated by the serum biochemistry results[3]. The femoral defect was classified using the Paprosky system as Type IIIB, and the acetabular defect as Type IIC.

TREATMENT

Two-stage total hip revisional surgery was conducted using a 3D-printed, customized antibiotic-loaded cement spacer (ALCS) during the first stage and a personalized proximal femur prosthesis (PFP) for the second stage. Postoperatively, intravenous vancomycin was administered twice daily at a dose of 15 mm/kg for the first 7 postoperative days, followed by oral moxifloxacin (400 mg every 24 h) for a further 2 wk as recommended by the DISA (Infectious Diseases Society of America) guidelines[4].

OUTCOME AND FOLLOW-UP

Postoperative inflammatory markers, including ESR and CRP, were monitored weekly for 8 wk, revealing the return to the normal range within 4 wk. The patient was kept non-weight bearing for 6 wk from the day of surgery, and then was allowed to partially weight bear for the following 6 wk before full weight bearing at 12 wk after surgery onwards. At her last follow-up (20 mo after surgery), she was asymptomatic and had significant functional improvement of her left hip with a Harris Hip Score of 91. Radiographs demonstrated no signs of implant loosening (Figure 2), and her serum markers were within normal limits.

Figure 2 Radiographs of the pelvic taken 20 mo after the second-stage surgery. A: Pelvic plane; B: Anteroposterior plane; C: Lateral plane.

DISCUSSION

This report describes a challenging case of chronic PJI with a concomitant segmental femoral defect, which were managed by a two-stage revisional procedure using custom-made, 3-D printed ALCS and PFP, respectively. There were several key learning points throughout the treatment pathway that will be beneficial for surgeons faced with this challenge in the future.

Custom-made antibiotic-loaded cement spacer

Prefabricated antibiotic-loaded interval spacers are available in various configurations. However, certain cases with complex anatomy and pathoaetiology warrant custom-made spacers. In the previous literature, both standard and customized spacers have similar infection clearance rates, and each has their own merits based on the clinical circumstances[5,6]. In this case, the treating surgeon attempted to manually transform an “off-the-shelf” spacer to fix the anatomy[7], but the reformed spacers were inadequate. Therefore, customized spacer molds were designed using computed tomography (CT) and three-dimension (3D) model data (Figure 3A and B). The molds were divided into two blocks, which could be accurately aligned using complementary locating bars and holes. Several discharge channels were included to allow space for excess cement to be removed (Figure 3C and D). The custom-made ALCS (Figure 4A and B) replaced the infected prosthesis to create a near anatomical left hip joint (Figure 5A). The patient was so satisfied with the first-stage revision that she consistently refused her scheduled 2nd-stage until a second fall occurred 6 mo after the first-stage surgery (Figure 5B).

Figure 3 Design process of the customized spacer molds. A: Reconstruction image of the prosthesis and left hip; B: The blueprint of the spacer according to the reconstruction image; C: The blueprint of the customized spacer molds; D: The blueprint of the assembled spacer molds.

Figure 4 Molding process of the custom-made spacer cement. A: The molds and the binding bundle of Kirschner wires (orange arrow); B: Spacer cement and the pressure rods (white arrow).

Figure 5 Radiographs of the pelvic taken the day after the first-stage revision (anteroposterior plane) (A) and the left hip taken 6 mo after the first-stage revision (B). The spacer stem was bent (anteroposterior plane).

A binding bundle of Kirschner wires surrounded by several single wires was settled to strengthen the positioning of the ALCS. This remained functional in the patient's body for nearly 6 mo (2 to 3 times longer than expected).

In our experience, the advantages of custom-made spacers included retention of limb length and lateral offset, both of which made it easier to perform further revisional surgery[8]. Moreover, custom-made spacers also allow the treating surgeon to control the type and dosage of antibiotics[9].

Antimicrobial therapy

After reviewing sensitivities of the bacterial culture, 2 g of vancomycin were combined with each pouch of PALACOS MV+G cement, which delivered a safe and effective dosage of gentamicin[10]. Because ALCS can deliver high local concentrations of antibiotics, this can enter systemic circulation and result in toxicity or other adverse reactions such as acute renal failure, hepatic failure, and bone marrow depression[11,12]. Due to the high local concentration of vancomycin in the custom-made ALCS, the concentration of intravenous vancomycin administered postoperatively was down-titrated to ensure safe levels of delivery. The patient’s serum vancomycin concentration after surgery has been maintained above twice the minimal inhibitory concentration as recommended by Whiteside et al[13].

Custom-made, 3D-printed prosthesis

Reports to date of the operative management of severe proximal femoral osteopenia (classified as Paprosky types IIIB and IV) have included impaction grafting[14], allograft prosthesis composite (APC)[15,16], and prosthetic implants (i.e., modular mega-prostheses)[17]. Each of these methods has unique advantages and limitations[17-19]. Standard modular prostheses are an available option for proximal femoral reconstruction in many cases and have been developed to be broadly applicable across several patient groups and fracture morphologies. Where standard prosthetic implantation is feasible, the estimated 5-year survival rate is encouraging at approximately 90.7%[20]. However, for some cases, custom-made prosthesis is needed to facilitate reconstruction (Table 1)[21-26].

Table 1 Literature review of custom-made femoral implants related total hip arthroplasty (with or without infection).

Ref.	No. of patients	Patient age (yr)	Follow-up (yr)	PJI	Type of femoral defect	Clinical outcome	Complications	Custom method
Jones et al[21]	1 in 9	60	3.3	Chronic (for 50 yr)	Girdlestone resection	No recurrence of infection; walk unaided	-	-
Hsieh et al[22]	9 in 24	59 (average)	4.2 (average)	All chronic	Type-III1: 6 caseType-I1: 3 case	No recurrence of infection	2 fractures & 1 dislocation	Spacer and femoral cement prosthesis with allografts
Westerman et al[23]	1	14	0.8	No infection	III-B2	Symptom free	-	CT reconstruction
Wang et al[24]	1	73	2	No infection	III-B2	Symptom free	-	3D printed titanium sleeve-prosthetic with allografts
Kamath et al[25]	1	68	1.5	Chronic for both knee and hip	IV2	Hip disarticulation	TKA incision breakdown for infection	Mating of a PROSTALAC spacer with an intramedullary nail
Angelini et al[26]	1 in 41	66	1.5	1.3-mo after the first surgery	III-B2	Healed	Deep infection	3D-printed prosthetic implant

¹Classified according to the system proposed by the American Academy of Orthopaedic Surgeons.

²Classified according to Paprosky classification. PJI: Periprosthetic joint infection.

To reconstruct this large, atypical segmental femoral bone deficiency, a custom-made PFP was designed and manufactured by a qualified medical implant provider (Beijing Chunlizhengda Medical Instruments Corporation, Beijing, China) (Figure 6A). To adjust the lower limb length to fit the uneven proximal cortical bone, three accessory ring blocks of different height (5 mm, 10 mm, and 15 mm) were made available. The 10 mm block was chosen intraoperatively to neutralize any shortening of the femur. The postoperative radiographs showed excellent resolution of the proximal femoral defect with the custom-made prosthesis. The patient regained a near-anatomical hip joint with significant symptomatic improvement after years of discomfort and loss of function (Figure 6B and C).

Figure 6 The custom-made prosthesis with porous design, and full lower limb radiographs taken the day after the second-stage revision. A: The custom-made prosthesis with porous design; B: Anteroposterior plane; C: Lateral plane.

CONCLUSION

In this case report, we have demonstrated the safety, feasibility, and effectiveness of two-stage revisional surgery for chronic PFI with a concurrent segmental femoral defect using a 3D-printed customized ALCS (first-stage) and a custom-made PFP (second-stage). We propose that the advantages of the custom-made ALCS are retention leg length and lateral offset, facilitating second stage revision, a robust fixation, and a low risk of dislocation or breakage. The apparent advantage of the custom-made PFP is near-perfect anatomical reconstruction of the affected hip with maximal preservation of bone tissue. Although manufacturing custom-made spacers and femoral prostheses is expensive and time-consuming, it presents a useful alternative when there is no suitable standard implant.

ACKNOWLEDGEMENTS

The authors are thankful to the Wenwen-Sun from the Department of Pathology, The First Affiliated Hospital of Wenzhou Medical University for her help in pathology. We are thankful to the patient enrolled in this study.