Cephalomedullary fusion nails for treatment of infected stemmed revision total knee arthroplasty: Four case reports

Abstract

BACKGROUND

Salvage of the infected long stem revision total knee arthroplasty is challenging due to the presence of well-fixed ingrown or cemented stems. Reconstructive options are limited. Above knee amputation (AKA) is often recommended. We present a surgical technique that was successfully used on four such patients to convert them to a knee fusion (KF) using a cephalomedullary nail.

CASE SUMMARY

Four patients with infected long stem revision knee replacements that refused AKA had a single stage removal of their infected revision total knee followed by a KF. They were all treated with a statically locked antegrade cephalomedullary fusion nail, augmented with antibiotic impregnated bone cement. All patients had successful limb salvage and were ambulatory with assistive devices at the time of last follow-up. All were infection free at an average follow-up of 25.5 months (range 16-31).

CONCLUSION

Single stage cephalomedullary nailing can result in a successful KF in patients with infected long stem revision total knees.

Key Words: Knee fusion; Knee arthrodesis; Intramedullary nail; Cephalomedullary nail; Total knee infection; Case report

Core Tip: Long stem infected revision total knees are challenging and are often treated with above the knee amputation. The authors provide a limb salvage technique for conversion to a knee fusion. A lateral approach to the femur and tibia with extended osteotomies allows for implant removal. A long cephalomedullary nail, supplemented with antibiotic cement, provides for a functional fusion. This a major surgical procedure that will likely involve blood transfusions and intensive care management, and post operative wound problems are common. However, if successful, patients can expect to walk with a shoe lift and a walking aide.

INTRODUCTION

Infection after a revision total knee arthroplasty (TKA) is a devastating complication. It may often be the result of staged treatment of previous prosthetic infection. Chronic antibiotic suppression without surgery is usually not successful. Excisional arthroplasties are unstable and poorly tolerated but can be considered in selected patients[1]. Additional revision arthroplasty procedures can be considered. However not all infections can be successfully resolved, and some patients may not be medically able to undergo repeated surgeries. At that point, knee fusion (KF) or above knee amputation (AKA) are possible remaining options. The optimal treatment is a matter of debate, and becomes a shared decision between patients, their families and clinicians[2-6].

In the presence of persistent infection, AKA is the best procedure to eradicate infection[3]. However, it often is associated with the need for repeated surgeries, high mortality, and poor function[7-9]. Although some patients can be satisfied with an AKA[10,11], others will not accept this procedure. KF for treatment of an infected total knee can be associated with significant complications[12,13]. Despite this it can be a durable solution that is associated with better overall function than an AKA[6,7,14,15].

CASE PRESENTATION

Chief complaints

We present four patients with persistent infected revision stemmed total knee arthroplasties in which an AKA was recommended. All were painful and had undergone previous attempts at resolution of their infection. Each refused an above the knee amputation.

Case 1: A 73-year-old male presented with right prosthetic knee pain, inability to ambulate and sepsis.

Case 2: A 78-year-old female presented with right prosthetic knee pain, swelling and inability to ambulate.

Case 3: A 59-year-old male presented with right prosthetic knee pain and inability to ambulate.

Case 4: An 84-year-old male presented with left revision prosthetic knee pain, inability to ambulate and sepsis.

History of present illness

Each presented with pain, persistent infection as documented with aspirate culture and laboratory studies.

History of past illness

Case 1, 2 and 3 had undergone numerous previous surgeries (Table 1). Case 4 (an 84-year-old man) with multiple medical comorbidities including chronic kidney disease and numerous surgeries on his left prosthetic knee had a long stem revision rotating hinge prosthesis in place (Figure 1A). He developed recurrent infection that did not respond to arthrotomy, exchange of the articulating components, and intravenous antibiotics. He became septic and an urgent AKA was recommended. Both he and his family refused amputation, but did consent to a KF.

Figure 1 Imaging results. A: Stitched anteroposterior images of the left femur, knee and tibia illustrating a well fixed, chronically infected left long stem revision total knee replacement; B: Post operative long standing bone alignment film illustrating the left cephalomedullary nail, healed femoral and tibial osteotomies as well as significant shortening of the left leg.

Table 1 Summary of patient demographics.

Case	Age	Sex	BMI (kg/m2)	Comorbidities	Prior knee surgeries (n)	Description of surgeries (year)	Previous post-operative infective organism
1	73	M	63	Morbid obesity; coronary artery disease; type 2 diabetes; atrial fibrillation neuropathy/chronic ipsilateral heel sore; hypertension; chronic venous stasis - right leg; sleep apnea; chronic anemia	4	Initial right TKA (2010); articulating antibiotic cement spacer (2016); long stem revision (2016); debridement with prosthesis retention (2019)	Escherichia coli, Proteus mirabilis
2	78	F	28	Non-Hodgkin’s lymphoma; hypertension; history of deep vein thrombus; history of melanoma; history of basal cell cancer	3	Initial right TKA (2005); long stem revision rotating hinge TKA (2019); arthrotomy (2023)	Coagulase negative staphylococcus
3	59	M	42	Morbid obesity; dyslipidemia; history of alcoholism	5	Initial right TKA (2020); arthrotomy (2021); arthrotomy/poly exchange (2021); articulating knee spacer (2021); long stem revision TKA (2021)	Streptococcus mitis; Enterobacter cloacae; Enterococcus faecalis; Coagulase negative staphylococcus
4	84	M	27	Stage 3 chronic kidney disease; hypothyroidism; chronic pulmonary disease; carotid stenosis; hypertension; Alzheimer’s disease; sleep apnea	7	Initial left TKA (2015); articulating spacer (2016); revision TKA (2017); patellar realignment (2017); second articulating spacer (2017); long stem rotating hinge revision TKA (2018); arthrotomy/poly exchange (2022)	Serratia marcescens

BMI: Body mass index; M: Male; F: Female; TKA: Total knee arthroplasty.

Personal and family history

All had multiple medical comorbidities (Table 1).

Physical examination

All patients had multiple healed anterior knee scars from previous surgeries.

Laboratory examinations

Laboratory results indicated pre-operative infective organisms (Table 1).

Imaging examinations

Prior to operative intervention, radiography imaging was conducted.

FINAL DIAGNOSIS

Infected long stem TKA.

TREATMENT

Case 1

Single stage removal of the long stem revision TKA and insertion of cephalomedullary fusion nail.

Case 2

The patient underwent surgery for removal of her chronically infected long stem revision and insertion of an antibiotic cement spacer and cephalomedullary fusion nail.

Case 3

Single stage removal of the long stem revision TKA and insertion of cephalomedullary fusion nail.

Case 4

Single stage removal of the long stem revision TKA and insertion of cephalomedullary fusion nail. He had an 11.5 mm diameter by 70 cm nail placed (Figure 1B). He developed a post operative wound dehiscence that healed without further surgery. He had daily dressing changes for 5 weeks. He received a 6-week course of intravenous antibiotics. He was ambulatory with a walker during his initial hospital stay, and advanced to independent ambulation with Lofstrand forearm crutches and a shoe lift.

Operative technique for all cases

Following general anesthesia with endotracheal intubation, a urinary catheter and radial arterial line were inserted. The patient was placed in the lateral decubitus position on a radiolucent table (Figure 2A). A long lateral incision was made over the femur, knee and tibia, away from the previous anterior incisions. Laterally based osteotomies of the femur and tibia were used to remove the long stems of the infected knee components (Figure 2B-D)[16]. The patellar button and all retained cement were removed. After extensive lavage the wounds were closed and a separate prep, drape, and new surgical set up was employed.

Figure 2 Intraoperative appearance and related surgical field manipulations of knee arthroplasty revision. A: Pre-operative appearance of the lower extremity, illustrating the previous anterior knee incisions; B: Long lateral incision through healthy tissue, followed by laterally based osteotomies of the distal femur and proximal tibia to expose the revision stems; C: Use of a metal cutting bur (Metal cutting heliocoidal rasp, Stryker instruments, Portage, MI, United States) to aid use exposure and stem removal; D: Appearance of the femoral and tibial osteotomies after stem removal.

A long cephalomedullary antegrade nail (Smith and Nephew Trigen KF Nail, Memphis, TN, United States) was inserted with C-arm fluoroscopic assistance. The femoral and tibial osteotomies were repaired using 18-gauge stainless steel monofilament cerclage wires around the long fusion nail. The lower extremity was shortened as needed to attempt bone contact between the femur and tibia and to assist with wound closure. Proximal fixation was accomplished with two 6.5 mm cephalomedullary screws. All nails were distally locked with two lateral-to-medial 5.0 mm screws. Two packages (80 g) of manually prepared antibiotic cement containing 6 g of powdered vancomycin and 4.8 g of powdered tobramycin was placed in the bony defects at the knee and metaphyseal areas of the femur and tibia. The wounds were closed over suction drains.

OUTCOME AND FOLLOW-UP

Case 1

Patient was ambulatory with a walker and shoe lift at his last follow-up visit (28 months).

Case 2

Patient was ambulatory with a walker and shoe lift at her last follow-up visit (27 months).

Case 3

Patient was ambulatory with a cane and shoe lift 31 months post KF.

Case 4

Patient was ambulatory with a crutch and shoe lift. He died 16 months later from unrelated causes.

Summary of outcomes and follow-up

Patient demographics, operative summary, and outcomes are presented in Tables 1, 2 and 3. There were 3 males and one female. The average age was 73.5 years. Body mass index ranged from 27 kg/m² to 63 kg/m². The average number of preoperative surgeries on the affected knee prior the KF procedure was 4.75 (range 3 to 7).

Table 2 Operative summary of patients with infected long stem revision.

Case	Operative knee	Pre-op revision implant	Fusion nail diameter (mm)/Length (mm)	Operative time (hours)	Estimated blood loss (mL)	Intra-operative transfusion (mL)
1	Right	Stryker triathlon revision CCK	13/700	6	3600	1800
2	Right	Biomet rotating hinge OSS	11.5/700	8	3500	1800
3	Right	Biomet vanguard revision SSK	11.5/800	10	1500	1200
4	Left	Biomet rotating hinge OSS	11.5/700	10	400	300

Table 3 Summary of patient outcomes.

Case	ICU LOS (days)	Wound complication	Total post-op knee surgeries (n)	Description of subsequent surgeries	Follow-up (months)	Ambulatory at last follow-up
1	7	Wound dehiscence	1	Incision and drainage ipsilateral thigh abscess	28	Yes, with rolling platform walker and heel lift
2	8	Wound dehiscence	3	Incision/drainage leg skin graft substitute; skin graft	27	Yes, with walker and shoe lift
3	3	Wound dehiscence	1	Skin graft substitute	31	Yes, with cane and shoe lift
4	1	Wound dehiscence	0	N/A	16 (deceased)	Yes, with Lofstrum crutch and shoe lift

ICU: Intensive care unit; LOS: Length of stay; N/A: Not applicable.

The average time in the surgical suite was 8.5 hours, which included the two separate operative procedures and set up time between them. All patients went to the intensive care unit intubated and were extubated the following day. The average blood loss was 2250 mL (400 mL to 3600 mL), and all patients received intraoperative blood transfusions (average 1275 mL, range 300 mL to 3600 mL). They spent an average of 4.75 days in the intensive care unit (range 1 to 8).

All patients experienced some form of wound dehiscence. Three required further surgery. At the time of latest follow-up, all were clinically infection free, off antibiotics, and none had a draining sinus. All were ambulatory with waking aides (walker, crutches, cane) and three used an external shoe lift. All were satisfied with their decision to salvage their lower extremity. No specific patient reported outcome measures were performed. The average follow-up was 25.5 months (range 16 to 31). Three of the patients were alive at the time of this report. One died of causes unrelated to his knee surgery (see illustrative case).

DISCUSSION

AKA results in inferior clinical results to KF, with many patients unable to walk. Thus, KF should be strongly considered a superior salvage procedure. Better functional results can be expected, including some degree of ambulation. A variety of techniques are available to perform KF, including external fixation, plating, intramedullary nailing, specialized modular nails, and combined modalities in the setting of failed TKA[17]. The complication rates for KF after periprosthetic knee infection can be high[18].

Our series represents a distinct subset of these patients: Those with long stem infected revision prostheses. Unfortunately, surgical treatment options are more limited in this group. External fixation and plating are not possible. Modular fusion nails offer the advantage restoration of limb length and alignment[19-22] but may not provide enough proximal fixation. Long antegrade fusion nails can provide good clinical results[23-25] but can place the patient at risk for peri-implant fracture of the proximal femur if cephalomedullary fixation is not employed[26]. Attempted arthrodesis can be performed in 1 or 2 stages depending on the virulence of the organism, soft tissue envelope, patient factors and surgeon preference. Bone loss at the knee can be filled with allograft, metal spacers or cement[27].

These patients have had previous anterior knee incisions that predispose them to wound problems and the potential need for local or free flap coverage. The senior author chose a lateral approach to intentionally avoid the anterior soft tissues, along with shortening as needed to allow for wound closure and bony contact between the femur and tibia. Although all had some level of post operative wound dehiscence, no patient required flap coverage, and all eventually healed. Three of the four patients had a limb length discrepancy and required an external shoe lift. Makhdom et al[27] used a similar technique employing an antibiotic coated cephalomedullary nail.

This case report has several limitations. It is a small clinical case series, and as such it may not be applicable to patients in other settings. No patient reported outcome measures were performed. The follow-up was relatively short, and it is possible that the 3 surviving patients may develop late infection with longer follow-up[28]. The knee was not studied with advanced imaging like a metal reducing computerized tomography scan to assess bony fusion. The antibiotic cement block around the nail likely functioned as an artificial functional fusion[27]. The three survivors could develop implant loosening with longer follow-up. Many patients may not be able to tolerate such an extensive surgery and surgeons may opt for an amputation instead of such a complex reconstruction.

CONCLUSION

In summary KF should be strongly considered in the treatment of an infected long stem revision TKA that has failed previous two stage re-implantation. Only long cephalomedullary nails offer satisfactory stability after implant removal and protection of the proximal femur in this setting. This is a complex reconstruction with many potential complications, including death. However, if successful, patients can expect to walk with assistive devices and shoe lift due to limb shortening. Post operative wound problems and secondary surgeries for wound coverage are common. Late infection is possible and could result in subsequent AKA or hip disarticulation or mortality[6].

ACKNOWLEDGEMENTS

The authors would like to thank Sundaye Moore, for assistance in the preparation of this manuscript.