Functional Outcome of Above-Knee Amputation After Infected Total Knee Arthroplasty.

Background: Periprosthetic joint infection is a serious complication of total knee arthroplasty (TKA). Management usually involves irrigation and debridement, polyethylene liner exchange, one-stage revision, two-stage revision, knee arthrodesis, or ultimately above-knee amputation (AKA). We present our experience with 21 patients who underwent AKA as a sequela of unresolved infected TKA, highlighting their etiology and functional outcomes. Methods: A retrospective chart review was performed for all cases of infected TKA treated with AKA at 1 institute from January 2007 to December 2020, with a minimum follow-up of 1 year. Patient demographics, Charlson comorbidity index, culture results, ambulation status, prosthesis fitting, and functional outcomes were collected. Short Form-36 and activities of daily living questionnaires were used for functional outcome assessment. Results: Twenty-one patients were identified, 7 of whom were male (33.3%). Mean ± standard deviation follow-up was 5.7 ± 3.1 years (range, 1-11 years). Mean ± standard deviation age was 57.9 ± 10.7 years (range, 38-87 years), and the mean body mass index was 33.5 ± 6.4 kg/m2 (range, 25.4-46 kg/m2). Gram-positive organisms were identified in 15 cases (66.7%). Prosthesis fitting was successful in 17 patients (81%). Post-AKA ambulation was achieved in 12 patients (57.1%). The ambulating group showed higher Short Form-36 and activities of daily living scores when compared with patients who did not ambulate (60.2 vs 43.3, P = .041, and 67.2 vs 52.7, P = .029, respectively). Conclusions: AKA should be considered solely as the final recourse for infected TKA. Despite the low-to-moderate patient-reported postoperative outcomes, prosthesis fitting and maintaining ambulation can improve postoperative functional outcomes.

Tobramycin Blood Levels after Local Antibiotic Treatment of Bone and Soft Tissue Infection.

Local antibiotic delivery using different carriers plays an important role in both infection prophylaxis and treatment. Besides dead space management, these carriers have the advantage of providing a high concentration of local antibiotics with a lower risk of systemic toxicity. Few studies have reported on systemic toxicity associated with antibiotic-impregnated carriers. The present study investigates the systemic tobramycin concentration at 24, 48 and 72 h postoperatively after using tobramycin-loaded polymethyl methacrylate (PMMA) and calcium sulfate (CS) as local antibiotic carriers. Additionally, this work assesses the renal function postoperatively for indications of acute kidney injury (AKI). Fifty-two patients were treated in 58 procedures with tobramycin and vancomycin-loaded PMMA, CS, or both. All systemic tobramycin levels were <2 mcg/mL at 72 h, and the resulting rate of AKI was 12% (7/58). In conclusion, local tobramycin antibiotic delivery using PMMA, CS, or both remains a safe and effective modality in the treatment of osteomyelitis as long as the surgeon is aware of its possible nephrotoxic effect.

Outcomes of Total Knee Arthroplasty in Patients With a Prior Contralateral Above-Knee Amputation: A Retrospective Review of a Nationwide Database.

BACKGROUND: Total knee arthroplasty (TKA) in patients with a prior contralateral above-knee amputation (AKA) is uncommon, with limited literature describing the outcomes. We used a national database to compare the outcomes of primary TKA in above-knee amputees and nonamputees. METHODS: A retrospective review of TKA recipients with prior contralateral AKA was performed using the PearlDiver database from 2010 to Q2 of 2019. Subjects and outcomes were identified using Current Procedural Terminology and International Classification of Diseases, Ninth and Tenth Revisions (ICD-9 and ICD-10). Patients were identified and matched at a 1-to-3 ratio with nonamputee (AKA group = 931; nonamputee group = 2792 patients). Perioperative outcomes and length of stay (LOS) were compared at 90 days, 6 months, 1 year, 3 years, and 5 years after TKA. RESULTS: The AKA group had a longer LOS (5.19 vs 3.00, P < .001) and higher overall complications rate (33.8% vs 11.8%). At all studied time intervals, the AKA group had higher periprosthetic infections, revisions, mechanical complications, and respiratory failure (P < .001), as well as surgical site infection, pneumonia, and blood transfusion (P < .05). CONCLUSION: Our study revealed higher overall complications and longer LOS among TKAs in prior contralateral above-knee amputees. Surgeons should evaluate the risks and benefits of performing a TKA on patients with prior contralateral AKA.

Reconstructive Options for Tibial Bone Defects.

Segmental bone defects of the tibia are amenable to multiple treatment options including classic bone transport, shortening and then lengthening, induced membrane technique, transport over a nail, free fibular grafting, and medial transport of the ipsilateral fibula. These treatment options have relative advantages and disadvantages, depending on defect size, soft-tissue characteristics, the presence or absence of infection, and associated morbidity. Relatively, few large comparative studies exist, and surgeons are left to their own experience and the opinion of experts within the field to guide surgical decision-making.