PATELLAR RESURFACING

Several high quality studies with contradictory results conclude that patellar resurfacing and non-patellar resurfacings are both viable options. Nine high quality studies reported equivalent functional outcomes with resurfaced versus non-resurfaced patellae using the KSS function (Raaij 2020 Aunan 2016, Dong 2018, Kaseb 2018, Roberts 2015), range of motion (Kaseb, 2018, Roberts 2015, Thiengwittayaporn 2019), stiffness (Aunan 2016), KOOS-ADL (Raaij 2020, Dong 2018, Aunan 2016, Ali 2016), KOOS Symptoms (Aunan 2016, Ali 2016, Kang 2019), KSS stairs (Roberts 2015), and Feller patellofemoral scores (Koh 2019). Such equivalence was furthered by one additional moderate quality study (Kaseb 2019) and three low quality studies (Albrecht 2016, Hsu 2006, Chun 2017). Only three high quality studies suggested improvement in certain function metrics among patients with patellar resurfacing, including the KSS function score (Ha 2019), active range of motion (Roberts 2015), and total patellar score (Thiengwittayaporn 2019).

Five high quality analyses reported no difference in pain metrics including VAS pain (Kaseb 2018, Ali 2016, Koh 2019), Kujala anterior knee pain scale (Kaseb 2018), anterior knee pain as a symptom (Dong 2018, Thiengwittayaporn 2019), continued pain (Koh 2019), and the feller patellofemoral score for anterior knee pain (Koh 2019) among patients with and without patellar resurfacing after TKA. Similarly, one low quality study supported equivalent pain metrics among patients with resurfaced versus non-resurfaced patellae after TKA (Chun 2017). KOOS-Pain with resurfaced versus non-resurfaced patellae was analyzed in two high quality studies with contradictory findings (Raaij 2020, Aunan 2016). One high-quality study suggested better anterior pain at rest and while walking in the non-resurfaced cohort (Roberts 2015). Finally, two high quality studies (Raaij 2020, Ali 2016) reported similar KOOS-QoL and KOOS-Sports scores regardless of patellar management while one study (Aunan 2016) reported superior KOOS-QoL and -Sport scores among patellar resurfacing patients.

Composite knee scores demonstrated a similar pattern of conflicting findings, with the majority of studies describing equivalent outcomes according to WOMAC (Kaseb 2018, Chun 2017), HSS (Kaseb 2018, Chun 2017), KOOS total (Kaseb 2018, Kaseb 2019), and the Feller patellofemoral scores (Dong 2018, Koh 2019). In contrast, the KSS total score was found to be higher among patients who underwent patellar resurfacing according to three (Dong 2018, Aunan 2016, Ha 2019) of seven high quality studies, while the remaining studies reported no difference based on patellar management (Raaij 2020, Kaseb 2018, Roberts 2015, Thiengwittayaporn 2019).

Four high-quality studies highlighted that adverse event rates were similar regardless of patellar management, including total revisions (Dong 2018), infection (Aunan 2016), crepitus (Dong 2018, Thiengwittayaporn 2019, Koh 2019), patellar fracture, and quadricep tendon rupture (Aunan 2016).

Benefits/ Harms of Implementation

Patellar resurfacing may be associated with improvement in certain patient-reported outcome scores such as KOOS-Pain, QoL, and Sports. However, such improvement is inconsistent and remains substantially disputed. In contrast, despite their relatively low incidence, potential complications of patellar resurfacing include but are not limited to loss of bone stock, increased future revision complexity, patellar fracture, avascular necrosis, and extensor mechanism violation, which may be catastrophic in the setting of primary elective TKA.

Outcome Importance

Reoperation, long term anterior knee pain, and patient satisfaction.

Cost Effectiveness / Resource Utilization

Unsurfaced patella poses the benefits of a faster surgery, avoiding potential complications of patellar resurfacing, and decreased cost compared to resurfacing. However, such potential benefits need to be balanced against the potential risk of requiring resurfacing at a later date, and revision rates.

Acceptability

Literature is conflicted regarding patellar management after primary elective TKA. As such, provider-preference based patellar management should be acceptable to medical providers. It is important to emphasize that this recommendation applies to primary knee arthroplasty. Physicians should exercise caution based on anatomic and bone-stock variability among patients as well as the patient-specific activity level, age and risk of future revision.

Feasibility

There are no significant barriers to implementation of recommendation. Elimination of patellar resurfacing may reduce operative time, blood loss and additional expenses.

Future Research

Large multicenter prospective RCT or cohort studies to assess indications for selective patellar resurfacing.

Addtional References:

Kang H, Zheng R, Dong C, Fu K, Wang F. No influence of patellar fixation technique on clinical outcomes of double-bundle medial patellofemoral ligament reconstruction: a systematic review. Arch Orthop Trauma Surg Germany, 2019;139(1):79–90.