What’s New in Adult Reconstructive Knee Surgery

This annual review highlights the most noteworthy and impactful studies in adult reconstructive knee surgery published over the past year. Emphasis was placed on studies with higher levels of evidence, including randomized trials and large cohort studies, as well as on award-winning research. Although studies across a range of evidence levels were considered, priority was given to those with the greatest potential to influence clinical practice. Treatment of Mild to Moderate Knee Osteoarthritis Biologic strategies to treat and to prevent the progression of knee osteoarthritis continue to gain traction. Several recent studies have noted that higher platelet doses appear to be a key determinant of the clinical success of platelet-rich plasma (PRP) injections for knee osteoarthritis. Although the use of PRP remains controversial without substantial evidence of prevention of osteoarthritis progression, a systematic review of 29 randomized controlled trials (RCTs) showed significant improvements (p < 0.01) in clinical outcomes with a higher mean platelet dose (5,500 ± 474 × 106) than those with a lower dose (2,302 ± 437 × 106)1. Corticosteroid injections remain a cornerstone of conservative management for knee osteoarthritis, but their use in patients with type-2 diabetes is often limited by concerns regarding hyperglycemia. In a post hoc analysis of a Phase-2 randomized trial involving 33 patients with knee osteoarthritis and type-2 diabetes, extended-release triamcinolone acetonide was associated with significantly less disruption of glycemic control compared with immediate-release triamcinolone acetonide, offering a potentially safer alternative for this high-risk population2. Arthroscopic debridement for knee osteoarthritis remains controversial. A systematic review reported good to excellent patient-reported outcome measures (PROMs) in patients with Kellgren-Lawrence grade-1 or 2 disease, with lower conversion rates to arthroplasty (0% to 4.5%) compared with the conversion rates of patients with Kellgren-Lawrence grade-3 disease (7.6% to 50%)3. However, the only RCT found no benefit of debridement over optimized nonoperative care4. These findings indicate that, although arthroscopic debridement may offer short-term symptom relief in select patients with mild to moderate knee osteoarthritis unresponsive to conservative treatment, its overall short-term and long-term effectiveness remains uncertain. Unicompartmental Knee Arthroplasty (UKA) Indications and Outcomes Modern indications for UKA are broader than the historical Kozinn and Scott criteria. Current absolute contraindications include uncontrolled inflammatory arthritis, a body mass index (BMI) of >35 kg/m2, flexion contracture of >10°, coronal deformity of >10°, and lateral facet patellofemoral arthritis5. UKA accounts for approximately 10% of all knee arthroplasties worldwide, although regional variation is substantial. In the United States, utilization increased by >590% between 2012 and 20226. The impact of obesity on UKA outcomes remains under debate, but recent evidence is reassuring. In a large, single-institution series of 4,973 medial UKAs performed with cement, the implant survivorship was 95.7% at 5 years and 92.8% at 10 years. Higher BMI modestly increased revision risk at thresholds of 30 kg/m2 and 35 kg/m2; however, BMI of >40 kg/m2 was not associated with a significant difference in implant survivorship compared with BMI of ≤40 kg/m2. Arthritis progression was the most common cause of revision, whereas infection rates remained consistently low across BMI categories. Improvements in PROMs were similar across all BMI groups (≤30 kg/m2 and >30 kg/m2, ≤35 kg/m2 and >35 kg/m2, and ≤40 kg/m2 and >40 kg/m2), with patients with BMI of >30 kg/m2 reporting greater gains in the Knee Injury and Osteoarthritis Outcome Score, Joint Replacement (KOOS JR) (p = 0.034)7. Lateral UKA Although medial UKA remains the most common UKA, lateral UKA is being performed with increasing frequency. A 2025 multicenter matched analysis of 124 lateral UKAs and 124 medial UKAs reported no significant differences in reoperation rates, PROMs, or functional performance at 2 years8. These early results support lateral UKA as a safe and effective option for isolated lateral disease, although longer follow-up is required. Technology-Assisted UKA Robotic-assisted UKA improves the accuracy of component positioning, typically achieving alignment within 1° of the preoperative plan, and facilitates consistent ligament balancing. Recent studies have confirmed that robotics enhances radiographic accuracy and reduces outliers, although these technical advantages have not consistently translated into superior patient-reported outcomes9. Importantly, robotics does not increase overall complication rates, although device-specific issues may occur10. With broader adoption, robotic assistance may help to mitigate the surgeon volume effects observed in registry data. UKA Revision UKA continues to demonstrate higher revision rates than total knee arthroplasty (TKA). A systematic review of 56 studies comprising nearly 30,000 UKAs (mean follow-up, 13 years) reported an overall revision rate of 8.8%, with a mean time to revision of 6.5 years11. Conversion of UKA to TKA yields favorable outcomes. In a high-volume institutional series of 439 conversions, the 10-year survivorship of aseptic conversion TKA (95.6%) was equivalent to that of primary TKA (95.8%) and superior to that of first-time revision TKA (84.2%). The leading causes of UKA failure included osteoarthritis progression (31%), tibial loosening or subsidence (27%), polyethylene wear or osteolysis (23%), and femoral loosening (9%)12. Collectively, these findings support UKA as a safe treatment option for which TKA is a reliable salvage when necessary. Primary TKA Antibiotic Prophylaxis and Infection Prevention The prevention of surgical site infections and periprosthetic joint infections (PJIs) remains an important frontier in total hip arthroplasty (THA) and TKA. A national database analysis of 528,250 primary TKAs found that cefazolin prophylaxis, either alone or with another antibiotic, was associated with a significantly lower 90-day PJI rate (0.7%) compared with non-cefazolin regimens (1.0%). After adjustment, cefazolin-only (odds ratio [OR], 0.68) and combination therapy (OR, 0.74) both reduced infection risk, supporting cefazolin as the preferred prophylactic agent when not contraindicated13. The safety of cefazolin use in patients with penicillin allergy has traditionally been called into question due to concerns about cross-reactivity. A large retrospective study of 49,842 patients undergoing primary THA or TKA found that cefazolin use in those with a reported penicillin allergy was associated with a very low rate of mild allergic reactions (0.1%), comparable with or lower than rates with alternative antibiotics. No differences were observed in superficial or deep infection or Clostridium difficile rates14. A retrospective study of 8,456 patients undergoing THA or TKA found that cefazolin administration in those with documented penicillin anaphylaxis was not associated with increased risk of anaphylaxis or clinical compromise. Among 214 such patients who received cefazolin, only 1 had an event requiring epinephrine or rapid response, which was not significantly different. In contrast, vancomycin use was linked to markedly higher odds of such events. These findings support cefazolin’s safety in patients who have an anaphylactic allergy to penicillin and its role in reducing reliance on less effective second-line antibiotics15. In an RCT, 1,022 patients were randomized to receive 2 g of intrawound vancomycin powder compared with no vancomycin prior to arthrotomy closure. There was no significant difference (p = 0.264) in the rate of PJI in the vancomycin group (0.2% [n = 1]) compared with the control group (0.58% [n = 3]), but vancomycin was associated with a higher rate of wound complications (13.2% [n = 67]) compared with the control group (7.56% [n = 39]) (p < 0.05)16. Another prospective study similarly found no difference in 90-day PJI rates but also noted no difference in wound complications with the use of intrawound vancomycin17. The use of intraosseous vancomycin continues to gain traction. In a retrospective review of 1,923 primary TKAs, intraosseous vancomycin (used in 1,359 cases) demonstrated significantly lower PJI rates at 90 days (0.5% compared with 1.6%), 1 year (0.7% compared with 1.8%), and 2 years (0.9% compared with 2.4%) compared with intravenous vancomycin (used in 564 cases). No significant differences were observed in thromboembolic events, wound complications, or incidence of acute kidney injury18. The adoption of extended oral antibiotics for infection prevention is becoming widespread, with a national database of >1.35 million TKAs between 2010 and 2022 showing a 321% increase in extended oral antibiotic use after primary TKA and a 368% increase after revision TKA. Utilization rates were similar in high-risk and general patients19. Prescription of extended oral antibiotics increased from 0.9% to 8%, with similar growth in standard-risk and high-risk patients. Trends were not explained by patient comorbidities, suggesting shifts in prescribing practices20. There are conflicting reports on the efficacy of extended oral antibiotics in reducing the incidence of PJI. In 1 retrospective study of 4,576 patients undergoing primary THA or TKA, a 10-day course of extended oral antibiotics demonstrated no significant difference in PJI rates at 90 days (1.0% compared with 0.8%) or 1 year (1.0% compared with 1.0%) compared with controls. In high-risk patients, PJI rates did not reach significance (0.8% compared with 2.3%). No increase in C. difficile infection or antibiotic resistance was observed21. A retrospective study of nearly 3,000 cases showed that a 7-day postoperative course of oral cefdinir significantly lowered (p = 0.04) 3-month PJI rates after primary TJA from 0.74% to 0.23%, a 3.85-fold risk reduction22. A recent meta-analysis of approximately 19,000 patients across 18 studies revealed that patients receiving extended oral antibiotics were 35% less likely to develop PJI compared with controls. the benefit was for primary THA and aseptic revision TKA, but not for primary and A meta-analysis of studies found that intravenous significantly and levels at 2 to without increasing events. These findings that intravenous is a safe and management to after There has been a the adoption of for TKA over the past In a large national database study of patients undergoing TKA between 2012 and the use of increased from to whereas the use of prophylactic was in patients but increased across all risk analysis showed that use was associated with lower odds of deep and compared with of risk in patients with a of was found to be as effective as in and deep after THA and In of the risk 1 database study found obesity of to be associated with a greater incidence of (OR, in patients who primary No differences in rates were found when BMI was to to kg/m2, to kg/m2, and kg/m2 in a retrospective compared with oral was associated with significantly lower odds of and complications compared with for These findings are by a meta-analysis of which demonstrated the safety and effectiveness of compared with oral The of the may a role in its retrospective study found that incidence was lower with compared with with similar complication The safety and efficacy of have also been demonstrated in the revision and The of the of and Knee randomized patients who primary TKA to receive of either intraosseous or intravenous The intraosseous compared with intravenous significantly lower the postoperative reduced postoperative and early and patient A RCT of patients undergoing primary TKA the of an compared with in the patients received The preoperative group demonstrated significantly lower and lower and a lower incidence of at The of the randomized patients who primary TKA across to receive or intravenous The dose in lower reduced at and on postoperative was in the group on postoperative but were no differences in complications, of or outcomes In an RCT of patients undergoing TKA, doses of or a preoperative dose significantly lowered the incidence and of postoperative or and reduced compared with The demonstrated superior benefit over the with no difference in In patients with type-2 diabetes intravenous benefit only increasing with no long-term glycemic impact in patients without diabetes, had a on postoperative is a common symptom after TKA. In a systematic and appear to clinical but the evidence remains limited to a for their A recent systematic review and meta-analysis demonstrated that early under after TKA results in nearly the flexion gain and lower complication and revision rates compared with similar There is between the alignment in TKA. In a series of patients who TKA, patients who knee alignment demonstrated greater and higher patient compared with alignment at 2 with no differences in or revision alignment a tibial joint to a than in patients with joint the joint which may knee In another study of TKA, alignment femoral to the tibial or and alignment similar outcomes at a mean of although patients preferred the and reported higher The of the demonstrated that functional alignment TKA than alignment but similar outcomes patients with functional alignment the and PROMs were demonstrated in a of patients with preoperative of the The of the demonstrated that postoperative TKA alignment to a did not influence PROMs at a follow-up, suggesting that outcomes on surgical and coronal alignment Although the use of polyethylene has survivorship and of THA the long-term outcomes after TKA remain A RCT of TKAs with found no differences in femoral component or PROMs at 5 years between and polyethylene In another RCT of TKAs with a mean follow-up, was no difference in overall reoperation risk, radiographic or clinical outcomes between and No in the however, 1 of osteolysis was observed in the suggesting that may offer long-term Modern continue to A systematic review and meta-analysis the outcomes of TKA compared with TKA performed with cement, on implant published studies demonstrated superior survivorship in patients years of a demonstrated greater early that by 10 suggesting long-term A large institutional registry study compared the outcomes after TKAs performed with and TKAs that between and a mean follow-up, the overall revision rate was low and similar between groups for the TKA group compared with for the TKA performed with were the most common for revision, whereas aseptic loosening was but common in tibial all of which within the postoperative year. demonstrated equivalent survivorship to A large national database study compared outcomes between TKAs and TKAs performed with in matched patients between and all time and 5 the rates of aseptic loosening and revision were nearly between 5 aseptic loosening in 0.9% of TKAs compared with of TKAs performed with cement, and revision rates were for the TKA group and for the group that TKA performed with The TKA cohort demonstrated excellent survivorship for aseptic loosening and for The rates of aseptic loosening were similar across including patients who were years of Technology-Assisted TKA The efficacy of TKA continues to In an RCT TKA with TKA, robotic assistance a greater in and higher of relief compared with TKA, but showed no in of or to at A registry study of a compared TKAs and 439 short-term complication rates, at 1 and 2 and of patients achieving or in at 1 year were in both Outcomes and The of the of and 5 years after TKA in a multicenter cohort of patients. associated with included the of knee and of of were with from BMI and hip risk preoperative may and in patients undergoing TKA. In a cohort of patients with BMI of to kg/m2, a and were by patients and showed in achieving but the difference was not significant compared with In a systematic review and meta-analysis of patients who TKA that compared patients who a prior surgery and patients who did the group had lower of and periprosthetic A large retrospective cohort study of patients, with a mean follow-up of compared outcomes across BMI on patients of patients had a markedly higher risk of revision within the postoperative year ratio compared with which These patients had preoperative but improvements in and with functional gains associated with higher These findings that, although BMI of kg/m2 increased early revision risk, long-term outcomes and patient-reported remain A systematic review of 10 studies including the role of tibial in patients undergoing TKA. studies reduced aseptic loosening and failure with whereas found no outcomes were similar across and overall evidence was as very The results in the not support the use of tibial on obesity the for The of the in Joint in Knee a to for and for reporting in TKA. and patient the for both reporting at 1 and clinical outcomes (mean of a for and of the Revision TKA of and of A systematic review of revision TKAs revealed that infection aseptic loosening and periprosthetic were the leading causes of with an overall rate of is a but for revision TKA. In a cohort of for isolated flexion all PROMs significantly at a mean of with of patients the important difference achieving substantial clinical benefit and achieving a patient symptom The survivorship of was at with only of patients undergoing revision for Technology-Assisted revision TKA has and early A systematic review of cases across studies found that and revision TKA significantly reduced radiographic compared with revision compared with coronal alignment of both femoral and tibial and the joint compared with within time was increased by to but complication rates were not higher than those with revision remains a in revision TKA. A large, cohort of aseptic the of or to was no significant in aseptic compared with use of alone to These findings that, although and are for in cases of their use does not the risk of although at a rate of to remains of the most complications TKA. A systematic review and meta-analysis of cases reported failure rates of after and after with or demonstrated similar failure rates whereas were associated with lower failure rates and reduced although remain with obesity remain at increased risk for wound complications revision TKA. In a retrospective series of 214 patients of >35 kg/m2), wound compared with significantly reduced revision (0.8% compared with revision compared with complications compared with and compared with In contrast, an institutional series of aseptic found that BMI of >40 kg/m2 was associated with higher of reoperation for PJI and for cause on but these effects after for These findings that the surgical may be than BMI PJI Infection prevention continues to be a priority in aseptic revision TKA. The of the a multicenter study of aseptic revision vancomycin significantly lowered PJI incidence compared with intravenous compared with at 30 0.9% compared with at 90 and compared with at 1 year < A large, study of for PJI 90 cases compared and performed to The overall infection was with no significant differences between the and A multicenter randomized trial the safety of antibiotic in rapid arthroplasty for PJI. patients received antibiotic with and vancomycin an whereas patients groups antibiotics for No although 2 were linked to vancomycin and levels were often but consistently and rates were similar between The study that antibiotic is with into its efficacy for infection The of a large of published studies to the that received a higher of In to in this to adult reconstructive knee surgery are to this review after the with a about to help in an in this PRP injections for the treatment of knee the is significant and by platelet a meta-analysis of randomized controlled 2025 This meta-analysis 18 PRP with for knee osteoarthritis and on outcomes PRP demonstrated superior improvements in and and Osteoarthritis across all follow-up with relief the at and and functional the at time to analysis revealed that PRP including important relief at and whereas PRP to improvements over These findings that platelet significantly PRP with offering reliable and outcomes. A therapy similar outcomes compared to therapy after total knee a randomized clinical This randomized trial of patients who TKA and an management patients who either therapy or Among the patients who the those in both groups had equivalent outcomes in of functional range of patient-reported and at to 1 year. undergoing therapy no therapy and a mean of compared with patients undergoing who nearly therapy is a alternative for postoperative compared with although is to of from to These results offer patients a option knee knee and hip Joint joint arthroplasty continues to gain This systematic review evidence from studies to outcomes of knee and hip and those of knee and hip for were were often and had lower and of a arthroplasty was associated with significantly lower odds of and complications, and the rates of reoperation and were similar to those for of patients for surgery were the with success rates for knee by total knee and total hip outcomes and were equivalent or In within the of studies and the of knee arthroplasty continues to and to as hip and knee appear to outcomes that are at equivalent in superior to of in the prevention of after total hip or knee an analysis from the Joint This from the randomized trial in compared the of for prevention after THA or TKA. reduced within 90 days = but a mean of The years were with an ratio of the of greater in when higher treatment and longer follow-up were The that, although lowered rates compared with the benefit was Although studies have the efficacy and safety of after TKA, this study showed that may be when the of or its long-term is No difference in revision rate or survivorship between and TKA. Joint This prospective randomized study patients who TKA with 1 knee with a and the knee with a with a mean follow-up of 18 years. Outcomes at nearly 2 demonstrated no significant differences between and in Knee of range of radiographic or or revision rates compared with Importantly, no osteolysis was observed in either and survivorship at years was excellent and nearly in the group compared with in the Although are in knee a of the use of and This study that both these long-term and demonstrated a clinical over the of of on the of knee joint in patients with osteoarthritis a randomized controlled clinical The use of a to treat moderate osteoarthritis continues to This RCT the impact of on in patients with moderate to knee osteoarthritis and patients were randomized to either or a of the superior and increased knee at compared with treatment, supporting its role as an effective for and in with osteoarthritis. for knee osteoarthritis in patients with or a randomized clinical 2025 This clinical trial improves in patients who were or and had knee osteoarthritis. A total of were randomized to receive either oral or for with patients in the group a significantly greater in knee on the compared with (mean to = a moderate Although and were common with no were remains a patients, of have knee osteoarthritis. The results of this study that may relief in patients with knee osteoarthritis and or although in trials is The use of and in total knee arthroplasty does not the incidence of a randomized study in with a This large, prospective randomized study with nearly TKAs performed with and a mean follow-up of years the efficacy of and in reducing PJI compared with in primary TKA. groups received the antibiotic infection rates were similar (p = at and were no differences in for aseptic loosening or antibiotic resistance These results that did not the risk of PJI in primary TKA, and its use in the general is not surgical the A systematic review of and measures in total joint 2025 remain in total joint arthroplasty to surgical but concerns about their potential to increase and infection This systematic review found that these and that such as the and that the may increase although strategies such as and a help to clinical not demonstrate a increase in PJI risk from their for and of to patients, the that surgical be for and are This study highlights the for to infection risk with The of on knee osteoarthritis Joint This RCT the efficacy of an compared with in patients with moderate knee osteoarthritis. patients were randomized and were for The primary the total at 1 showed no significant difference between of the and the were not across time at (p = and (p = were significantly in the group compared with at No were reported in either These results indicate that did not or and was associated with outcomes at 1 its role as a treatment option for knee osteoarthritis. The effectiveness of platelet-rich plasma injections for mild to moderate osteoarthritis of the knee with joint or in a a clinical This RCT the efficacy of PRP injections in patients with mild to moderate knee osteoarthritis. patients were randomized to receive injections or and were for The PRP group showed significantly greater improvements in compared with = and higher rates of compared with = analysis also demonstrated significantly greater improvements in in the PRP group (p = No differences were observed in joint or important improvements in and relief compared with supporting its efficacy in this