Orthoplastics in Periprosthetic Joint Infection of the Knee: Treatment Concept for Composite Soft-tissue Defect with Extensor Apparatus Deficiency

The myocutaneous gastrocnemius flap for periprosthetic joint infection of the knee

Purpose

Periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) presents significant challenges, especially in elderly and comorbid patients, often necessitating revision surgeries. We report on a series of patients with confirmed PJI of the knee and concomitant soft-tissue/extensor apparatus defects, treated by using pedicled myocutaneous medial or lateral sural artery perforator (MSAP/LSAP) gastrocnemius flaps.

Methods

Our retrospective study at the Center for Musculoskeletal Infections, included patients with knee PJI undergoing pedicled myocutaneous MSAP/LSAP gastrocnemius flap reconstruction for combined soft tissue and extensor apparatus defects. The tendinous back of the gastrocnemius muscle was used and, if required, the Achilles tendon for extensor apparatus reconstruction, with the skin island addressing the cutaneous defect. Perioperative complications and postoperative outcomes after 1 year were evaluated, including functional and clinical assessments with the American Knee Society Score (AKSS).

Results

Eight patients (mean age 73 years; five female) were included, predominantly with Staphylococcus aureus infections. Six patients involved isolated MSAP flaps, two were extended with the Achilles tendon. The median time for wound healing was 9 days. Short-term follow-up showed successful reconstruction in seven patients, with minor wound dehiscence in one patient. One patient required flap revision for a perigenicular haemato-seroma and two patients were diagnosed with new haematogenous PJI infection. Significant improvement in AKSS scores after surgery was observed (functional AKSS: median 33-85; clinical AKSS: median 64-91, p = 0.001).

Conclusion

Pedicled myocutaneous MSAP/LSAP gastrocnemius flaps offer a safe, reliable and versatile option for reconstructing combined soft tissue and extensor apparatus defects in PJI after TKA. This approach yields excellent functional outcomes with minimal peri- and postoperative complications, which is particularly beneficial in elderly and comorbid patients and feasible in settings without microsurgical availability.

Level of evidence

Level IV.

Proceedings of the United Kingdom Periprosthetic Joint Infection Meeting 2022: Combined and Arthroplasty Sessions

Considerable variation in practice exists in the prevention, diagnosis, and treatment of periprosthetic joint infection (PJI), which is a devastating complication for patients and surgeons. The consensus principle has been increasingly embraced by the orthopaedic community to help guide practice, especially where high-level evidence remains unavailable. The third United Kingdom Periprosthetic Joint Infection (UK PJI) Meeting was held in Glasgow on April 1, 2022, with more than 180 delegates in attendance, representing orthopaedics, microbiology, infectious diseases, plastic surgery, anesthetics, and allied health professions, including pharmacy and arthroplasty nurses. The meeting comprised a combined session for all delegates, and separate breakout sessions for arthroplasty and fracture-related infection. Consensus questions for each session were prepared in advance by the UK PJI working group, based upon topics that were proposed at previous UK PJI Meetings, and delegates participated in an anonymized electronic voting process. We present the findings of the combined and arthroplasty sessions of the meeting in this article, and each consensus topic is discussed in relation to the contemporary literature.

Outcomes of the gastrocnemius flap performed by orthopaedic surgeons in salvage revision knee arthroplasty

Introduction: The gastrocnemius myofascial flap is used to manage soft-tissue defects over the anterior aspect of the knee in the context of a patient presenting with a sinus and periprosthetic joint infection (PJI) or extensor mechanism failure. The aim of this study was twofold: firstly, to evaluate the outcomes of gastrocnemius flaps performed by appropriately trained orthopaedic surgeons in the context of PJI and, secondly, to evaluate the infection-free survival of this patient group. Patients and methods: We retrospectively reviewed 30 patients who underwent gastrocnemius flap reconstruction during staged revision total knee arthroplasty for prosthetic joint infection (PJI). All flaps were performed by an orthopaedic surgeon with orthoplastics training. Patients had a mean age of 68.9 years (range 50-84) and were followed up for a mean of 50.4 months (range 2-128 months). A total of 29 patients (97 %) were categorized into Musculoskeletal Infection Society (MSIS) local extremity grade 3 (greater than two compromising factors), and 52 % of PJIs were polymicrobial. The primary outcome measure was flap failure, and the secondary outcome measure was recurrent infection. Results: Flap survival was 100 % with no failures or early returns to theatre for flap problems such as necrosis or haematoma. Overall infection-free survival during the study period was 48 % (13 of 27 infected cases). Using limb salvage as the outcome, 77 % (23 of 30 patients) retained the limb. Infection recurrence occurred in 48 % (10 patients) in the type B3 cohort and 67 % (4 patients) in the type C3 cohort ( p = 0.65 ). Conclusions: The surgical technique for a gastrocnemius myofascial flap is reliable and reproducible when performed by appropriately trained orthopaedic surgeons, even in high-risk groups. However, the risks of recurrent infection and amputation remain high within our series due to poor host and extremity factors.

Soft-tissue reconstruction in lower-leg fracture-related infections: An orthoplastic outcome and risk factor analysis

Introduction Fracture-related infection (FRI) is a severe post-traumatic complication which is occasionally accompanied by a deficient or even avital soft-tissue envelope. In these cases, a thoroughly planned orthoplastic approach is imperative as a vital and intact soft-tissue envelope is mandatory to achieve fracture union and infection eradication. The aim of this study was, to analyse if soft-tissue reconstruction (STR) without complications is associated with a better long-term outcome compared to FRI patients with STR complications. In particular, it was investigated if primary flap failure represented a risk factor for compromised fracture union and recurrence of infection. Patients and Methods Patients with a lower leg FRI requiring STR (local, pedicled and free flaps) who were treated from 2010-18 at the University Hospital Basel were included in this retrospective analysis. The main outcome measure was the success rate of STR, further outcome measures were fracture nonunion and recurrence of infection. Results Overall, 145 patients with lower leg FRI were identified, of whom 58 (40%) received STR (muscle flaps: n = 38, fascio-cutaneous flaps: n=19; composite osteo-cutaneous flap: n = 1). In total seven patients required secondary STR due to primary flap failure. All failures and flap-related complications occurred within the first three weeks after surgery. Secondary STR was successful in all cases. A high Charlson Comorbidity Index Score was a significant risk factor for flap failure (p = 0.011). Out of the 43 patients who completed the 9-month follow-up, 11 patients presented with fracture nonunion and 12 patients with a recurrent infection. Polymicrobial infection was a significant risk factor for fracture nonunion (p = 0.002). Primary flap failure was neither a risk factor for compromised fracture consolidation (p = 0.590) nor for recurrence of infection (p = 0.508). Conclusion: A considerable number of patients with lower-leg FRI required STR. This patient subgroup is complex and rich in complications and the long-term composite outcome demonstrated a high rate of compromised fracture consolidation and recurrent infections. It appears that secondary STR should be performed, as primary flap failure was neither a risk factor for compromised fracture consolidation nor for recurrence of infection. We propose to monitor these patients closely for three weeks after STR.

Microsurgical Reconstruction of the Lower Extremity in the Elderly

Demand has increased for complex lower-extremity reconstruction in the steadily growing elderly patient group in many highly developed countries. Microsurgery is indispensable for soft tissue reconstruction and osseous consolidation salvaging leg function and preventing amputation, with its devastating consequences. Microvascular reconstruction can be performed successfully in specialized centers with low donor-site morbidity, minimal operative time, and comparably low complication rates. However, this requires thorough multidisciplinary planning, preoperative optimization of risk factors, such as diabetes and malnutrition, and individually adapted intraoperative management. Implementing these principles can reliably restore ambulation and mobility, maintaining autonomy in this population.