Total patellectomy in knees without prior arthroplasty: a systematic review

Fracture-related infection of the patella: Treatment options and outcome

BACKGROUND

Fracture-related infection (FRI) after the operative management of patella fractures is a serious complication that can result in prolonged hospitalization, multiple revision procedures and permanent functional impairment. Till today, treatment modalities and outcome of FRI of the patella are not well described. Therefore, the main objective of this retrospective cohort study was to evaluate treatment options, functional outcome and healthcare costs related to FRI of the patella.

METHODS

This study evaluated 111 consecutive patients that were surgically treated for patella fractures, at the department of trauma surgery of the University Hospitals Leuven (Belgium), between January 2015 and April 2020. Patients were excluded if they (1) were younger than 18 years at the time of injury or (2) died during follow up. The minimal follow-up for all patients was 18 months.

RESULTS

During the 5-year study period, 107 patients with 108 patella fractures were included. A total of 10 patients were diagnosed with an FRI (9.3%). Four of these were treated with a DAIR approach and three patients underwent implant removal or exchange. Finally, three patients were treated with total patellectomy. Out of the 10 patients, two were diagnosed with a recurrence of infection. Overall, we observed substantial lower scores for all Knee Injury and Osteoarthritis Outcome Score subscales in the FRI group, compared to a reference population. Moreover, our study shows that direct hospital-related healthcare costs of FRI of the patella were nine times higher compared to non-FRI cases.

CONCLUSIONS

FRI of the patella is a challenging complication and recurrence of infection not uncommon. Although multiple treatment modalities exist, a multidisciplinary patient-specific approach is crucial. An early or delayed onset infection can be managed with a DAIR approach, but only when the construct is stable and the soft tissue coverage adequate. In patients with an FRI, implant removal is preferred when the fracture has healed. A total patellectomy can be used as a salvage procedure in complex cases with acceptable functional results. Overall, FRI of the patella leads to both a negative impact on the functional status of the patient and a ninefold increase in total healthcare costs.

Chondromalacia patellae: current options and emerging cell therapies

Chondromalacia patellae (CMP), also known as runner’s knee, typically occurs in young patients, which is characterized by anterior knee pain (AKP) that is associated with visible changes in patellar cartilage. The initial pathological changes include cartilage softening, swelling, and edema. CMP is caused by several factors, including trauma, increased cartilage vulnerability, patellofemoral instability, bony anatomic variations, abnormal patellar kinematics, and occupation hazards. CMP may be reversible or may progress to develop patellofemoral osteoarthritis. Quadriceps wasting, patellofemoral crepitus, and effusion are obvious clinical indications. Additionally, radiological examinations are also necessary for diagnosis. Magnetic resonance imaging (MRI) is a non-invasive diagnostic method, which holds a promise in having the unique ability to potentially identify cartilage lesions. Modalities are conventionally proposed to treat cartilage lesions in the PF joint, but none have emerged as a gold standard, neither to alleviated symptoms and function nor to prevent OA degeneration. Recently, researchers have been focused on cartilage-targeted therapy. Various efforts including cell therapy and tissue emerge for cartilage regeneration exhibit as the promising regime, especially in the application of mesenchymal stem cells (MSCs). Intra-articular injections of variously sourced MSC are found safe and beneficial for treating CMP with improved clinical parameters, less invasiveness, symptomatic relief, and reduced inflammation. The mechanism of MSC injection remains further clinical investigation and is tremendously promising for CMP treatment. In this short review, etiology, MRI diagnosis, and treatment in CMP, especially the treatment of the cell-based therapies, are reviewed.

Patella Alta in Ambulatory Children With Cerebral Palsy: Prevalence and Functional Significance

BACKGROUND

Gait dysfunction associated with patella alta (PA) in subjects with cerebral palsy (CP) has been presumed but not objectively established clinically or through biomechanical modeling. It is hypothesized that PA is associated with increasing level of motor impairment, increasing age, obesity, and worse stance phase knee kinematics and kinetics in children with CP.

METHODS

Retrospective case series of 297 subjects with CP studied in our Motion Analysis Center. Data analyzed included patient demographics (age, body mass index, CP classification), patella height (Koshino-Sugimoto Index), and knee kinematics and kinetics.

RESULTS

PA was present in 180 of 297 subjects (61%), in 68 of the 146 (47%) with unilateral CP, and 112 of 151 subjects (74%) with bilateral CP. For unilateral CP, the prevalence of PA was not significantly different between Gross Motor Function Classification System (GMFCS) I and II (P=0.357). For bilateral CP, the prevalence of PA in GMFCS III was significantly greater than in GMFCS I and II (P=0.02). Regression analysis showed a significant trend between increasing age and PA in unilateral and bilateral groups (P<0.001 and 0.001, respectively). The prevalence of PA was not significantly different across body mass index categories for either unilateral or bilateral groups. There were only 2 of 10 significant correlations between PA and gait parameters for subjects with unilateral CP functioning at the GMFCS I and II levels. There were 8 of 12 significant correlations between PA and gait parameters for subjects with bilateral CP functioning at the GMFCS I, II, and III levels.

CONCLUSIONS

PA is common in ambulatory children with CP across topographic types and motor functional levels. PA is well tolerated with respect to gait dysfunction in unilateral CP, but may contribute to crouch gait in bilateral CP. Gait dysfunction cannot be inferred from the radiographic assessment of patellar height, and radiographic evidence of PA by itself does not justify surgical correction with patellar tendon advancement or shortening.

LEVEL OF EVIDENCE

Level III-prognostic, retrospective series.

Medial Quadriceps Tendon Femoral Ligament Reconstruction After Patellectomy: A Treatment for a Dislocating Quadriceps Tendon

The medial quadriceps tendon femoral ligament (MQTFL) reconstruction is an alternative to the patellar bony fixation of the medial patellofemoral ligament reconstruction for the treatment of lateral patellofemoral dislocation. We describe the first report of a unique application of this technique in a patient with a previous patellectomy to treat a dislocating quadriceps tendon. An active 59-year-old Caucasian man presented 25 years after patellectomy with a dislocating quadriceps tendon and significant dysfunction. Stabilization of the knee extensor mechanism with an MQTFL reconstruction and retensioning of the quadriceps complex by tibial tubercle distalization provided stability and improved function. Extensor tendon instability is a rare complication after patellectomy that can cause significant pain and dysfunction. Successful stabilization of the quadriceps mechanism through an MQTFL reconstruction can provide excellent patient satisfaction and functional results. This technique may have implications for patellofemoral instability surgeries and in cases of knee extensor dysfunction after total knee arthroplasty.

De Novo Reconstruction of a Hybrid Patella by Staged Fabrication of a Microvascular Bone Transplant with an Osteointegrated Prosthetic Socket

Total patellectomy is sometimes unavoidable but usually results in severely impaired function, pain, and instability in the affected knee. Any patellar prosthetic solutions rely on a certain amount of remaining bone and therefore are not applicable after total patellectomy. Traditionally, reconstruction of a neopatella by avascular or allogeneic bone grafts is hampered by mechanical failure, resorption, or infection. We developed a new, 3-stage approach to reconstruct a hybrid patella composed of a revascularized scapula tip transplant fabricated with a prosthetic socket. The procedure is safe and provides optimal healing and prosthetic osteointegration through viable bone and dynamic stability to the considerable load a patella has to bear in unrestricted mobility. The technique also demonstrates successful integration of orthopedic prosthetic devices into current flap fabrication concepts.