Fusion rate of 89% after knee arthrodesis using an intramedullary nail: a mono-centric retrospective review of 48 cases

PURPOSE

Knee arthrodesis is an established procedure for limb salvage in cases of recurrent infection, total knee arthroplasty soft tissue defect, poor bone stock or a deficient extensor mechanism. Surgical options include compression plate, external fixator and arthrodesis nail. Different types of nail exist: long fusion nail, short modular nail and bridging nail. This study presents the results on knee arthrodesis using different types of intramedullary nails. The aim is to assess if a specific type of nail has a better fusion rate, clinical outcome and lower complication rate.

METHODS

A mono-centric retrospective study of 48 knees arthrodesis was performed between 2000 and 2018. 15 T2^™ Arthrodesis Nail, 6 OsteoBridge^® Knee Arthrodesis and 27 Wichita^® fusion nail were used. The mean clinic and radiological follow-up was 9.8 ± 3.8 years (2.6-18 years).

RESULTS

Fusion rate was 89.6%. Time to fusion was 6.9 months. Mean Parker score was 6.9/9 points. Visual Analogic Scale was 1.9. The Wichita^® fusion nail showed better results in terms of fusion, time to fusion and clinical outcome measured by Parker score and VAS but without statistical significance. The early revision rate was 10.4% and 20.8% presented a late complication requiring a surgery, due to nonunion or infection. 93.3% of infection was cured. Two patients live with a fistula (4.2%) and 1 was amputated (2.1%).

CONCLUSION

Although burdened by a big complication rate, knee arthrodesis with an intramedullary nail provides satisfactory results and is a good alternative to above-knee-amputation. The Wichita^® fusion nail shows a tendency to better results compared to the two other nails.

LEVEL OF EVIDENCE

Case series, level IV.

Prosthetic-joint Infections: Mortality Over The Last 10 Years

Background: There is a constant increase of joint arthroplasties to improve the quality of life of an ever-aging population. Although prosthetic-joint infections are rare, with an incidence of 1-2%, they represent a serious complication in terms of morbidity and mortality. Infection related mortality is known to be approaching 8% at one year. The aim of this retrospective study is to reassess the one and two-year mortality over the last ten years. Methods: Patients treated for prosthetic joint infection at the University Hospital of Lausanne (Switzerland) between 2006 and 2016 were included. The one and two-year cumulative mortality depending on sex, age, type of prosthesis, infecting organism and type of surgical treatment were computed. Results: 363 patients (60% hips, 40% knees) were identified with a median age of 70 years. The one-year cumulative mortality was 5.5% and it was 7.3% after two years. No difference was seen between hip and knee prostheses, but the mortality was higher in men than in women and increased with age. Furthermore, there was a significant difference depending of the germ with enterococci infections associated with a higher risk of death. Finally, patients treated with a one-stage or two-stage exchange had a lower mortality than those treated with debridement and retention. Conclusion: The mortality is still high and differs according to sex, age, infecting organism and type of surgical treatment. There is a need of studies to improve the management of patients at risk of increased mortality.

Economic Analysis in a Diagnosis Related Groups System for Two-stage Exchange of Prosthetic-joint Infections

Background: There is a constant increase of joint arthroplasties performed, with an infectious risk of 1-2%. Different therapeutic options for prosthetic-joint infections exist, but surgery remains essential. With a two-stage exchange procedure, a success rate above 90% can be expected. Currently, there is no consensus regarding the optimal interval duration between explantation and reimplantation. This retrospective study aimed to assess the economic impact of a two-stage exchange from a single-hospital perspective.

Methods: 21 patients who have undergone a two-stage exchange of a hip or knee prosthetic-joint infection at the University Hospital of Lausanne (Switzerland) from 2012 to 2013 were included. The revenues earned according to the Swiss Diagnosis Related Groups (SwissDRG) system introduced in 2012 and the costs were compared for each hospital stay.

Results: The remuneration ranged from 26'806 to 42'978 Swiss francs (CHF) (~ 22'905-36'723 EUR, median 36'338 CHF, ~ 31'049 EUR). The median total cost per patient was 76'000 CHF (~ 65'000 EUR) (51'151 to 118'263; hip median 79'744, knee median 66'708). The main determinant of the costs was the length of the hospital stay. Revenues never covered all the costs, even with a short-interval procedure. The hospital lost a median of 35'000 CHF per patient (~ 30'000 EUR) (22'280 to 64'666).

Conclusion: The current DRG system may not be specific enough for rewarding prosthetic-joint infections. Several options could be considered to act on the length of the hospital stay. In order to cover costs in complicated cases, such as prosthetic-joint infections, more specific DRGs are needed.

Body sodium/blood volume state in normotensive members of normotensive and hypertensive families

Exchangeable sodium is lower than normal in young male patients with essential hypertension. This may reflect a primary abnormality of sodium metabolism, or natriuresis caused by sodium-independent elevation of arterial pressure. To investigate this question, 31 normotensive men with positive and 31 normotensive men with negative family history of essential hypertension were studied. Blood pressure tended to be higher in the former (121/78 +/- 9/8 (s.d.) versus 113/74 +/- 11/9 mmHg; P less than 0.005); mean age, urinary sodium or potassium excretion, plasma sodium, potassium, renin activity or aldosterone levels and creatinine clearance were comparable. Exchangeable sodium and blood volume were also similar in the two groups, when expressed in absolute values (3113 +/- 306 versus 3044 +/- 242 mmol and 4902 +/- 581 versus 4769 +/- 579 ml, respectively) or in relation to body surface area (100.8 +/- 7.1 versus 100.2 +/- 6% and 103.8 +/- 12.2 versus 102 +/- 11.3%). In both groups, exchangeable sodium and blood volume were unrelated to arterial pressure. The body sodium/blood volume state is normal in normotensive subjects with positive family history. The low exchangeable sodium of young patients with essential hypertension does not appear to reflect a primary familial abnormality of body sodium metabolism.