Short-term differences in anterior knee pain and clinical outcomes between rotating and fixed platform posterior stabilized total knee arthroplasty with a new femoral component design

SPECT/CT and triple-phase bone scan: A valuable diagnostic approach for identifying indications for secondary patellar resurfacing in patients with unexplained anterior knee pain post-TKA

OBJECTIVE

The efficacy of secondary patellar resurfacing (SPR) in alleviating anterior knee pain (AKP) following total knee arthroplasty (TKA) remains uncertain. The purpose of this study was to assess the suitability of SPR using single photon emission computed tomography/computed tomography (SPECT/CT) in conjunction with triple-phase bone scan (TPBS).

METHODS

We performed a retrospective analysis on a prospectively-enrolled cohort of patients suffering from AKP in the context of TKA. In this cohort, we identified a subset of 17 patients (involving 18 knees), who had unexplained AKP and were potential candidates for secondary patellar resurfacing (SPR). The candidates for SPR were designated the experimental group, and subjects receiving other forms of treatment were referred to as the Control group. The selection for these treatment options was based on the findings from SPECT/CT and triple-phase bone scan (TPBS). Data collection spanned from preoperative to postoperative follow-up periods and encompassed basic demographics, preoperative findings of SPECT/CT plus TPBS, and Knee Society Score (KSS).

RESULTS

SPECT/CT and TPBS revealed focal radionuclide concentration in the patella in 12 patients (13 knees) and in other locations in 5 patients (5 knees) with unexplained AKP, complementing the findings from medical history and physical examinations. The Experimental group showed signs of patellar maltracking or early-stage patellofemoral osteoarthritis (OA) following TKA and received SPR treatment. Postoperatively, the objective knee indicators score was significantly higher than preoperative scores (88.46 ± 5.77 vs. 76.38 ± 7.64, P < 0.05). Similarly, the functional activities score was significantly improved postoperatively (74.31 ± 6.68 vs. 50.46 ± 9.01, P < 0.05). Patient satisfaction score was substantially elevated after SPR (33.38 ± 2.87 vs. 17.08 ± 5.69, P < 0.05). The control group mainly included patients who experienced loosening, periprosthetic joint infection (PJI), or instability. These patients received revision surgeries tailored to their individual pathologies and postoperative follow-ups showed favorable outcomes.

CONCLUSIONS

SPECT/CT in combination with TPBS may serve as a valuable tool for assessing the suitability of SPR for the post-TKA management of unexplained AKP. Video Abstract.

Prokineticin 2 and Cytokine Content in the Synovial Fluid of Knee Osteoarthritis and Traumatic Meniscal Tear Patients: Preliminary Results

Knee osteoarthritis (OA) is a chronic degenerative inflammatory-based condition caused by a cascade of different intra-articular molecules including several cytokines. Among the cytokines, prokineticins (PKs) have recently been identified as important mediators of inflammation and pain. This observational study examined the potential involvement of PK2 in degenerative or traumatic knee disease. Fifteen patients presenting knee osteoarthritis (OA group) and 15 patients presenting a traumatic meniscal tear (TM group) were studied. Synovial fluid samples from affected knees were assessed for PK2, IL-10, and TNF-α using the ELISA method. At a long-term follow-up (minimum 5 years, mean = 6.1 years), patients in the TM group underwent clinical re-evaluation with PROMs (Tegner Activity Scale, IKDC, Lysholm, SKV); in addition, X-ray visualization was used to assess the presence of secondary OA. PK2 was detected in synovial fluids of both TM and OA patients and the levels were comparable between the two groups, while IL-10 levels were significantly greater in the OA group than those in TM patients. PK2 levels correlated with those of IL-10. PK2 levels were greater in blood effusions compared to clear samples, did not differ significantly between sexes, nor were they related to differences in weight, height, or injury (meniscal laterality, time since dosing). No correlation was found between PROMs and radiological classifications in patients in the TM group at final follow-up. These data are the first observations of PK2 in synovial fluid following traumatic meniscus injury. These findings suggest possible further prognostic indices and therapeutic targets to limit the development of secondary OA.

Multi-radius posterior-stabilized mobile-bearing total knee arthroplasty partially produces in-vivo medial pivot during activity of daily living and high demanding motor task

PURPOSE

The purpose of the present study was to assess the kinematical behavior of a multi-radius posterior-stabilized (PS) mobile-bearing (MB) total knee arthroplasty (TKA) during an activity of daily living (Sit-To-Stand-STS) and a high demanding motor task (Deep-Knee-Lunge-DKL) using model-based dynamic RSA. We hypothesized the achievement of medial pivoting movement in both motor tasks due to the congruent geometry of the inlay with the femoral component, which should allow good stability of the medial compartment, and to the high magnitude of rotations guaranteed by the MB on the tibial side.

METHODS

Twenty-two randomly selected patients were recruited and prospectively evaluated. The PS MB cemented TKA was implanted with the standard technique (medial parapatellar approach, adjusted mechanical alignment). At minimum 9-month follow-up, patients were examined with model based Dynamic RSA developed in our Institute (BI-STAND DRX 2) during the execution of two motor tasks: STS and DKL. The motion parameters were evaluated using the Grood and Suntay decomposition and the low-point kinematics methods.

RESULTS

In the extension phase of DKL femur performed a greater antero posterior translation of 3.8 mm compared to STS between 0° and 20° of knee flexion (p < 0.05). Low-point analysis showed a medial pivoting movement in both motor tasks: in 62% of patients during STS and 48% during DKL. Varus-valgus rotations were lower than 1° during all the range-of-motion in both motor tasks without differences.

CONCLUSIONS

Medial pivot was partially produced by this multi-radius PS MB TKA with some differences during activity of daily living (STS) and high demanding motor task (DKL).

LEVEL OF EVIDENCE

IV.