Citations

Background: Nonoperative and operative management techniques after anterior cruciate ligament (ACL) injury are both appropriate treatment options for selected patients. However, the subsequent development of posttraumatic knee osteoarthritis (PTOA) remains an area of active study. Purpose: To compare the risk of PTOA between patients treated without surgery and with ACL reconstruction (ACLR) after primary ACL disruption using a machine learning causal inference model. Study Design: Cohort study; Level of evidence, 3. Methods: A geographic database identified patients undergoing ACLR between 1990 and 2016 with minimum 7.5-year follow-up. Variables collected include age, sex, body mass index, activity level, occupation, relevant comorbid diagnoses, radiographic findings, injury characteristics, and clinical course. Treatment effects of ACLR on the development of PTOA and progression to total knee arthroplasty (TKA) were analyzed with machine learning models (MLMs) in a causal inference estimator (targeted maximum likelihood estimation, TMLE), while controlling for confounders. Results: The study included 1194 patients with a minimum follow-up of 7.5 years, among whom 974 underwent primary reconstruction and 220 underwent nonoperative treatment. A total of 215 (22%) patients developed symptomatic PTOA in the ACLR group compared with 140 (64%) in the nonoperative treatment group ( P < .001), whereas 25 (3%) patients underwent TKA in the ACLR group compared with 50 (23%) in the nonoperative treatment group ( P < .001). Patients in the ACLR group had delayed TKA compared with patients in the nonoperative treatment group (193.4 vs 166.0 months, respectively; P = .02). TMLE evaluation revealed that reconstruction decreased the risk of PTOA by 11% (95% CI, 8%-13%; P < .001) compared with nonoperative treatment but did not demonstrate a significant effect on the rate of progression to TKA. Survival analysis with random forest algorithm demonstrated significant delay to the onset of PTOA as well as time to progression of TKA in patients undergoing ACLR. Additional risk factors for the development of PTOA, irrespective of treatment, included older age at injury, greater body mass index, total number of arthroscopic knee surgeries, and residual laxity at follow-up. Conclusion: MLMs in a causal inference estimator found ACLR to exert a significant treatment effect in reducing the rate of development of PTOA by 11% compared with nonoperative treatment. ACLR also delayed the onset of PTOA and progression to TKA.

Background: Medial patellofemoral ligament reconstruction is frequently indicated for recurrent lateral patellar instability. The preoperative presence and severity of a J-sign have been associated with poorer postoperative outcomes. Purpose: To determine the underlying anatomic factors that contribute to the presence, severity, and jumping quality of the J-sign. Study Design: Cross-sectional study; Level of evidence, 3. Methods: All patients undergoing evaluation for patellar instability at a single institution between 2013 and 2023 and healthy controls without patellar instability were included. Patients with a history of knee osteotomies were excluded. The presence of a jumping J-sign and its relationship to patellofemoral measures including the Caton-Deschamps Index (CDI), trochlear dysplasia (Dejour grade), tibial tubercle–trochlear groove (TT-TG) distance, tibial tubercle lateralization, trochlear bump height, mechanical alignment, femoral anteversion, tibial torsion, trochlear medialization, patellar width, axial patellar/trochlear overlap, patellar height, trochlear height, and knee rotation angle (KRA) were measured using standardized 1.5-T magnetic resonance imaging (MRI). Univariate pairwise and multivariable analyses were performed to determine the factors associated with J-sign presence, severity, and quality. Results: Of the 130 knees with patellar instability, 89 (68.5%) demonstrated a J-sign on physical examination. In total, 44 (33.8%) patients demonstrated a 1-quadrant J-sign, 32 (24.6%) demonstrated a 2-quadrant smooth J-sign, and 13 (10.0%) demonstrated a jumping J-sign. A total of 22 control, noninstability cases were included. On multivariable analysis, increasing TT-TG distance (OR, 1.1 increase per millimeter; P = .04), external KRA (OR, 1.1 increase per degree; P = .02), and increasing CDI (OR, 1.3 increase per 0.1 increase in CDI; P = .02) were associated with J-sign presence. Increasing bump height (OR, 1.72 increase per millimeter; P = .007) and decreasing patellar width (OR, 0.89 decrease per millimeter; P = .076) were associated with a larger J-sign, when present. Increasing bump height (OR, 1.80 increase per millimeter; P = .018), increasing patellar width (OR, 1.33 increase per millimeter; P = .047), and decreasing CDI (OR, 0.009 decrease per 0.01 increase in ratio; P = .008) were associated with a jumping J-sign in comparison with a smooth 2-quadrant J-sign. A KRA of 10° (AUC, 0.70) and a cartilaginous bump height of 6.6 mm (AUC, 0.73) were thresholds associated with jumping J-sign presence. Conclusion: The presence of a J-sign is associated with MRI findings of relatively greater external tibiofemoral rotation, increased TT-TG distance, and increased patellar height, while J-sign severity and jumping quality are associated with the presence of additional underlying trochlear factors such as increased bump height. The anatomic drivers identified in this study should be further evaluated as possible factors associated with suboptimal outcomes after surgical management.

Background: Anterior cruciate ligament reconstruction (ACLR) is one of the most common orthopaedic procedures and one of the most well studied. Despite extensive research dedicated to ACLR, there is limited understanding of how chronic inflammatory systemic diseases (CIDs) such as rheumatoid arthritis and systemic lupus erythematosus affect outcomes. Purpose: To compare the outcomes of ACLR in cohorts of patients with and without CID. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective query of a regional data set was conducted for all patients who underwent ACLR from 1990 to 2021 for traumatic ACL rupture. All patients with CID were identified and propensity matched to non-CID controls. Baseline characteristics and clinical outcomes were identified through retrospective chart review, and patients were contacted for subjective outcomes. Results: A total of 30 patients with ACLR and a diagnosis of CID were identified. These patients were propensity matched to 120 non-CID controls. Baseline demographic and surgical characteristics demonstrated no statistical differences. Follow-up duration was similar between the CID and non-CID groups (mean, 14.6 vs 14.2 years; P = .868). The CID cohort had a higher arthrofibrosis rate (16.7% vs 4.3%; P = .031), higher osteoarthritis rate (33.3% vs 16.7%; P = .041), higher total knee arthroplasty (TKA) rate (16.7% vs 3.3%; P = .016), and earlier time to TKA (14.7 vs 23.5 years; P = .032). Knee range of motion, infection rate, retear rate, time to retear, and time to osteoarthritis were not statistically different between the cohorts. The CID cohort had higher visual analog scale pain scores (mean, 2.00 vs 1.20; P = .043) but slightly higher satisfaction (mean, 3.92 vs 3.39; P = .043). There were no differences in preinjury Tegner, postoperative Tegner, change in Tegner, or IKDC score. In a univariate Cox regression model, the CID cohort had a retear hazard ratio of 1.43 (95% CI, 0.46-4.51; P = .537). Kaplan-Meier survival revealed no significant differences in retear-free survival between the CID and non-CID cohorts at 25 years (85.7% vs 87.3%; P = .53). The CID cohort had a TKA hazard ratio of 3.94 (95% CI, 1.05-14.8; P = .042). Kaplan-Meier survival demonstrated significantly decreased TKA-free survival at 25 years in the CID cohort (64.9% vs 91.2%; P = .029). Conclusion: CID increases the incidence of arthrofibrosis, osteoarthritis, and TKA in those undergoing ACLR. Patients with CID also undergo TKA significantly sooner than non-CID counterparts. Notably, the majority of patient-reported outcome measures are no worse in patients who have a CID diagnosis. Thus, ACLR constructs themselves may not necessarily fare worse in patients with CID. Nonetheless, these patients need to be cautiously counseled on the clinical outlook after their ACLR.

ABSTRACTPurposeDouble‐level osteotomies (DLOs) have shown promising results for knee joint preservation, however, most ultimately progress in terms of degenerative disease resulting in conversion to total knee arthroplasty (TKA). Therefore, the purpose of this study was to examine the time to TKA conversion, long‐term clinical outcomes and revision rates of patients who have undergone TKA after prior ipsilateral DLO.MethodsPatients who underwent simultaneous or staged DLO and subsequently underwent conversion to TKA at a single academic institution from 1997 to 2022 were evaluated. The type of osteotomy performed (opening‐ vs. closing‐wedge), osteotomy hardware fixation, when and if osteotomy hardware was removed, implanted TKA components and revision rates were recorded. Postoperative outcomes, including Forgotten Joint Score‐12 (FJS‐12), Tegner Activity Scale score and subjective knee preference were also obtained.ResultsA total of 22 patients (24 knees) underwent TKA following DLO and were followed for an average of 26.1 ± 7.7 years. The average time from DLO to TKA conversion was 14.1 ± 6.5 years, with 70.8% of knees converting to TKA more than 10 years after DLO. The mean follow‐up after conversion to TKA was 12.0 ± 7.7 years. Only 12.5% of patients received a varus‐valgus or hinged‐constrained TKA. At the final follow‐up, the mean FJS‐12 was 75.8 ± 23.1, while the mean Tegner Activity Scale score was 2.5 ± 1.1. Seventy‐seven percent of patients had no subjective knee preference or preferred their DLO‐TKA knee. Only two knees (7.4%) underwent subsequent revision after index arthroplasty at a mean of 9.3 years postoperatively.ConclusionsA majority of DLOs (70.8%) converted to TKA after more than a decade. Subsequent TKA function was favorable as most patients had either no subjective knee preference or preferred their DLO‐TKA knee. This study demonstrates both long‐term joint preservation and uncompromised TKA function after prior DLO.Level of EvidenceLevel IV.

Background: Medial patellofemoral ligament reconstruction (MPFLR) is an excellent surgical option for patients with recurrent patellar instability. This technique has demonstrated significant improvements in patient-reported outcomes, high rates of return to sport, and low rates of failure. However, there is debate regarding the use of isolated MPFLR in the setting of concomitant pathoanatomic features such as patella alta, trochlear dysplasia, or a lateralized tibial tubercle. Purpose: To estimate the overall relative effect sizes as well as strength of evidence supporting described risk factors for recurrent instability after isolated MPFLR. Study Design: Systematic review and meta-analysis. Methods: A systematic review was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed, Embase, Cochrane, and Ovid/MEDLINE databases were queried. Clinical studies for outcomes of isolated MPFLR reporting recurrent instability and associated risk factors were included. Data for each risk factor analyzed by at least 2 studies were extracted, and the heterogeneity of studies was determined by I 2 value. For variables evaluated in studies determined to have fair homogeneity, defined as I 2 <25%, DerSimonian-Laird random-effects models were generated and effect sizes were represented as mean differences or odds ratios. Results: Nine studies examining risk for recurrent instability after isolated MPFLR were identified, with 5 overlapping risk factors with low heterogeneity between studies: age, sex, tibial tubercle to trochlear groove (TT-TG) distance, Caton-Deschamps Index (CDI), and trochlear dysplasia. There was strong evidence to support the risk of recurrent instability associated with CDI >1.3 (OR, 2.72; P = .02) and dysplasia with a trochlear bump (DeJour type B or D; OR, 3.28; P <.001). Age, sex, and TT-TG distance did not cause an increased risk of recurrent instability with currently available aggregate data. Conclusion: There are signs of increased risk of failure of isolated MPFLR in the setting of DeJour type B and D trochlear dysplasia and patella alta (CDI, >1.3). Currently available data suggest that age, sex, and TT-TG distance do not cause a higher risk of recurrence for patients undergoing isolated MPFLR.

Background: Mismatch between osteochondral allograft (OCA) donor and recipient sex has been shown to negatively affect outcomes. This study accounts for additional donor variables and clinically relevant outcomes. Purpose: To evaluate whether donor sex, age, donor-recipient sex mismatch, and duration of graft storage affect clinical outcomes and failure rates after knee OCA transplantation. Study Design: Cohort study; Level of evidence, 3. Methods: Patients undergoing knee OCA transplantation between 2003 and 2018 were prospectively followed. Inclusion criteria consisted of primary OCA transplantation and minimum 2-year follow-up. Patient descriptive data and allograft donor sex, age, and graft storage time before implantation were collected. Patients were evaluated for reoperation, failure, and achievement of clinically significant outcomes for International Knee Documentation Committee scores. Reoperation was defined as subsequent surgical intervention of the transplanted allograft, including second-look arthroscopy for graft evaluation, debridement, and loose body removal. Failure was defined as revision of the primary OCA transplantation or conversion to arthroplasty. A Kaplan-Meier curve determined cumulative survivability of OCA transplantations, and log-rank testing was used to compare survivorship between groups. Stepwise regression analysis was utilized to evaluate associations between donor variables and achievement of clinically significant outcomes, reoperation, and failure. Results: A total of 372 patients undergoing OCA transplantation were included and followed for a mean 5.4 years (SD, 2.7; range, 2.0-16.3). Isolated OCA transplantation was performed in 45% of cases (169/372). A mismatch in donor and recipient sex was present for more female patients (90%) than male patients (10%; P < .001). Those who had a sex-mismatched graft more frequently underwent concomitant tibial tubercle osteotomy ( P = .034). When controlling for patient sex, no other differences were seen between groups matched and mismatched by sex. Univariable and multivariable analysis found no significant difference in survival free from reoperation or failure on the basis of donor-recipient sex mismatch, donor age, or graft storage time before implantation. Conclusion: In contrast to previous historical data, no donor variables were associated with inferior clinical outcomes in patients who underwent OCA transplantation. These data can help inform graft selection, expedient recipient selection, and outcome optimization after OCA transplantation.

Background: Bucket-handle meniscal tears (BHMTs) are a common subtype of meniscal tears that represent a clinical challenge. Arthroscopic inside-out repair has been considered the gold standard in treatment; however, an all-inside approach has gained widespread popularity, with limited long-term evidence. Purpose/Hypothesis: The purpose of this study was to (1) compare long-term clinical outcomes and rates of failure after surgical repair of BHMTs using the all-inside versus inside-out technique, and 2) identify risk factors for failure at long-term follow-up. It was hypothesized that clinical outcomes and rates of failure would be similar between the 2 techniques. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who had undergone surgical repair of BHMTs between 2003 and 2013 at a single institution were identified. Patient-reported outcome measures (PROMs) were assessed preoperatively and at the latest follow-up using the Tegner scale, International Knee Documentation Committee questionnaire, and visual analog scale pain at rest and with activity. A univariate Cox proportional hazards model was used to identify predictors for repair failure, defined as revision meniscal surgery and/or documented meniscal retear. Results: In total, 63 patients were included (37 with inside-out repair, 26 with all-inside repair). At a mean follow-up of 11.2 years, the survival rate for BHMT repair was 63% overall, 70% for all-inside repairs, and 60% for inside-out repairs ( P = .37). The mean time to failure was 2.6 years for all-inside repairs and 2.5 years for inside-out repairs ( P = .98). PROM scores were not significantly different between the 2 repair groups ( P > .22). Univariate Cox proportional hazards model for failure demonstrated that increasing age at surgery was associated with lower failure rates (hazard ratio, 0.91 change per 1-year increase in age; 95% CI, 0.84-0.98) and medial meniscus repair was associated with higher failure rates (hazard ratio, 3.12; 95% CI, 1.14-8.77). Conclusion: Long-term follow-up of BHMT repair demonstrated satisfactory clinical outcomes and failure rates. In appropriately selected patients, the all-inside technique did not compromise outcome as compared with the inside-out repair techniques. For both methods, older age was associated with lower failure rates and medial meniscus repair was associated with increased failure.

Background: The microvasculature of the human meniscus has been previously described by Arnoczky and Warren. However, to date, the qualitative and quantitative extra-articular vascular anatomy of the medial meniscus has not been characterized. Purposes: To perform a qualitative and quantitative anatomic study of the extra-articular medial meniscal vasculature and to introduce the novel “medial meniscal artery” (MMA), potentially providing future guidelines for the treatment of meniscal abnormalities. Study Design: Descriptive laboratory study. Methods: A total of 33 unpaired, frozen human cadaveric knees were dissected. The femoral artery was identified and cannulated using an angiocatheter. The arteries were perfused with a red acrylic paint solution, allowing for improved visualization. Artery dimensions and distances were measured using a digital caliper. Perfused specimens were imaged using computed tomography and segmented using 3D reconstruction software to identify vessels and repeat artery measurements digitally. Results: The MMA was consistently identified in all specimens. In 27 (82%) of 33 specimens, the MMA branched directly from the popliteal artery; in 5 (15%), the MMA shared a common trunk with the inferior medial genicular artery; and in 1 specimen (3%), the MMA shared a common branch with the inferior lateral genicular artery. The MMA was easily distinguishable from the superior, inferior, and middle genicular arteries, given its direct course to the medial joint line with terminal branches to the posterior horn of the medial meniscus and deep to the semimembranosus tendon. The MMA exhibited a consistently smaller vessel diameter relative to the genicular arteries. Conclusion: This is the first study to identify and quantitatively describe the MMA in the human knee. The MMA can be identified consistently on gross anatomic dissection in cadaveric donors of varying demographics. Further research is needed to identify and characterize the artery in vivo and to determine the MMA’s role in meniscus preservation surgery. Clinical Relevance: The findings of this study will provide future avenues of research toward understanding medial meniscus vascularization and the genesis of potential degenerative changes when vascularization is poor. This will help to further refine diagnostic and treatment options for meniscus revascularization and compartment preservation. Additionally, this study may help define safe zones in the knee during posterior approaches and expand the base of knowledge for emerging vascular procedures such as genicular artery embolization.

AimsDistal femoral osteotomies (DFOs) are commonly used for the correction of valgus deformities and lateral compartment osteoarthritis. However, the impact of a DFO on subsequent total knee arthroplasty (TKA) function remains a subject of debate. Therefore, the purpose of this study was to determine the effect of a unilateral DFO on subsequent TKA function in patients with bilateral TKAs, using the contralateral knee as a self-matched control group.MethodsThe inclusion criteria consisted of patients who underwent simultaneous or staged bilateral TKA after prior unilateral DFO between 1972 and 2023. The type of osteotomy performed, osteotomy hardware fixation, implanted TKA components, and revision rates were recorded. Postoperative outcomes including the Forgotten Joint Score-12 (FJS-12), Tegner Activity Scale score, and subjective knee preference were also obtained at final follow-up.ResultsA total of 21 patients underwent bilateral TKA following unilateral DFO and were followed for a mean of 31.5 years (SD 11.1; 20.2 to 74.2) after DFO. The mean time from DFO to TKA conversion was 13.1 years (SD 9.7) with 13 (61.9%) of DFO knees converting to TKA more than ten years after DFO. There was no difference in arthroplasty implant systems employed in both the DFO-TKA and TKA-only knees (p > 0.999). At final follow-up, the mean FJS-12 of the DFO-TKA knee was 62.7 (SD 36.6), while for the TKA-only knee it was 65.6 (SD 34.7) (p = 0.328). In all, 80% of patients had no subjective knee preference or preferred their DFO-TKA knee. Three DFO-TKA knees and two TKA-only knees underwent subsequent revision following index arthroplasty at a mean of 12.8 years (SD 6.9) and 8.5 years (SD 3.8), respectively (p > 0.999).ConclusionIn this self-matched study, DFOs did not affect subsequent TKA function as clinical outcomes, subjective knee preference, and revision rates were similar in both the DFO-TKA and TKA-only knees at mean 32-year follow-up.Cite this article: Bone Jt Open 2024;5(11):1013–1019.

Purpose To evaluate the available literature on the relationship between knee bony morphology and medial meniscus posterior root tears (MMPRTs) to determine which tibiofemoral morphologic risk factors may predispose the development of MMPRTs. Methods Embase, MEDLINE, and PubMed databases were searched to identify all relevant human clinical studies investigating knee morphologic features and MMPRTs. Shape features were compared between control groups and patients with MMPRTs. The methodological index for nonrandomized studies (MINORS) instrument was utilized to assess the methodological quality of included studies. Results Thirteen level III evidence studies and 1 level IV evidence study were included in this review (n = 2,181), with 895 patients in the MMPRT group and 1,286 in the control group. Tibial morphology features associated with an increased risk for MMPRTs included an increased medial tibial slope (6 studies), increased tibial torsion (1 study), increased medial meniscal slope (1 study), and shallower medial tibial plateau concavity (1 study). Varus mechanical alignment was found to increase the risk for MMPRTs (4 studies). Femoral morphology features associated with an increased risk for MMPRTs included an A‐type intercondylar notch (1 study), increased medial femoral condyle (MFC) angle (1 study), narrower intercondylar distance (1 study), narrower intercondylar notch width (1 study), shorter MFC distal offset distance (1 study), increased MFC width (1 study), increased MFC to medial tibial condyle width ratio (1 study), greater distance between the medial tibial eminence and MFC (1 study), and smaller femoral offset ratios of both the medial and lateral condyles (1 study). Conclusions Multiple tibiofemoral shape features, including a steeper slope of the medial tibial plateau, greater varus alignment, and a narrower intercondylar distance and notch width, were found to be predictive factors for MMPRTs. Level of Evidence Level IV, systematic review of Level III and IV studies.