Autologous Chondrocyte Implantation and Tibial Tubercle Osteotomy for Patellofemoral Chondral Defects: Improved Pain Relief and Occupational Outcomes Among US Army Servicemembers

Tibial Tubercle Osteotomy: Indications, Outcomes, and Complications

PURPOSE OF REVIEW

The tibial tubercle osteotomy (TTO) is a versatile surgical technique used to treat a range of patellofemoral disorders, including patellar instability, painful malalignment, focal chondral defects, and patellar maltracking that have failed conservative therapies. TTO is a personalized procedure that can be tailored to the pathoanatomy of the patient based on physical examination and imaging. The complication rate associated with TTO strongly depends on the indication for surgery, the severity of the patient's condition, and the surgical approach. Despite the literature on TTO, to our knowledge, no single source has addressed the indications, techniques, outcomes, and complications of this procedure. The purpose of this article is to serve as such a valuable resource.

RECENT FINDINGS

Highlights from recent studies we would like to emphasize are two-fold. First, maintaining a distal cortical hinge yields lower complication rates than osteotomies involving complete tubercle detachment with classic or standard techniques. Second, based on current evidence, TTO consistently provides symptomatic relief, and most patients can return to work or sport at their pre-operative level within 3 and 6 months, respectively. TTO is a personalizable surgical technique that may be utilized for multiple patellofemoral disorders and is associated with good outcomes.

Timing of Outcomes and Expectations After Knee Surgery in the US Military: A Systematic Review

CONTEXT

Knee injury and subsequent surgery are widespread in the military setting. Associations between knee surgery and expected outcomes over time have not been consolidated and characterized systematically by procedure type across the body of literature, and the temporal expectations of these outcomes remain unclear.

OBJECTIVE

To summarize common postoperative follow-up times and associated outcomes that determine clinical or surgical failure in US service members after elective knee surgery.

DATA SOURCES

A systematic search was conducted with 3 bibliographic databases of published research reports from 2010 through 2021.

STUDY SELECTION

Studies in US military service members undergoing elective knee surgery, with a minimum of 1-year follow-up, and reporting on a functional/occupational outcome were included. Three reviewers screened all abstracts and full-text articles to determine eligibility.

STUDY DESIGN

Systematic review of longitudinal cohort studies.

LEVEL OF EVIDENCE

Level 2a.

DATA EXTRACTION

Extracted data included military demographics, surgical procedure variables, surveillance period, and outcome measures. The Newcastle-Ottawa Scale and the Grading of Recommendations Assessment, Development, and Evaluation approach were used to determine study quality and risk of bias.

RESULTS

A total of 22 studies (mean follow-up time of 40.7 months) met the inclusion criteria. For cruciate ligament repair, approximately one-third of patients required a second surgery or were medically separated from military service by 2 years from surgery; 100% were reinjured by 4 years, and 85% sustained a new injury within 5 years of surgery. For meniscal repair, nearly one-third of patients were medically separated, and half were placed on activity restrictions within 3 years of surgery. For articular cartilage repair, within 5 years, 39% of patients required a second surgery, 30% were placed on activity restrictions, and 36% were medically separated. For patellar repair, 37% of patients were medically separated and over half were placed on activity restrictions within 5 years.

CONCLUSION

Common knee surgeries can have long-term implications for military careers that may not become apparent with shorter follow-up periods (<2 years). When longer surveillance periods are used (eg, up to 5 years), additional surgical procedures are more common and the likelihood of being injured or medically separated from military service is higher.

More negative sagittal tibial tuberosity-trochlear groove distances are correlated with larger patellofemoral chondral lesion size

PURPOSE

The purpose of this study is to assess the association between sagittal tibial tuberosity-trochlear groove (sTT-TG) distance and patellofemoral chondral lesion size in patients undergoing cartilage restoration procedures.

METHODS

A retrospective cohort analysis of patients who underwent an osteochondral allograft transplantation or matrix-induced autologous chondrocyte implantation in the patellofemoral compartment, from 2010 to 2020, were included if they had patellofemoral high-grade lesions, magnetic resonance imaging (MRI) and minimum 2-year follow-up. The preoperative sTT-TG distance was measured independently on axial T2-weighted MRI sequences by two authors, each at least two weeks apart. Intraoperative lesion size was reported according to operative report measurements by the attending surgeon. An interclass correlation coefficient (ICC) was calculated to assess intra- and inter-rater reliability, and categorical data analysis and linear regression models were used to assess the relationship between sTT-TG and lesion size.

RESULTS

A total of 80 patients (50 females) with a mean age of 31.5 ± 10.4 years, body mass index of 27.0 ± 5.9 kg/m2 and follow-up of 61.5 ± 21.4 months were included. A total of 107 lesions were present: 63 patients with unipolar (patella = 41, trochlea = 22) and 22 with bipolar lesions. The mean MRI defect size was 1.6 ± 1.0 cm2 and the mean intraoperative defect size was 3.8 ± 2.4cm2. Intra- (ICC: 0.99,0.98) and inter-rater reliability (ICC: 0.96) were excellent for both MRI defect size and sTT-TG measurements. The mean sTT-TG was -4.8 ± 4.9 mm and was significantly inversely related to MRI defect size (-0.45, p < 0.01), intraoperative patellar lesion size (-0.32, p = 0.01), total lesion area (-0.22, p = 0.04), but not trochlear lesion size (-0.09, p = 0.56). Multivariable regression demonstrated a more negative sTT-TG remained an independent variable correlated with larger MRI-measured patellofemoral defect sizes and intraoperative patellar lesions.

CONCLUSION

A more negative sTT-TG was an independent variable correlated with larger patellofemoral lesions in patients undergoing patellofemoral cartilage restoration.

LEVEL OF EVIDENCE

Level III, Diagnostic.

Management Considerations for Unicompartmental Osteoarthritis in Athletic Populations: A Review of the Literature

Unicompartmental osteoarthritis in the young athlete poses a challenge for both patients and providers. Coronal plane malalignment is frequently a concomitant finding that adds to the complexity of management. Military surgeons are presented unique challenges, in that they must consider optimal joint-preservation methods while returning patients to a high-demand occupational function. Management options range from lifestyle changes to surgical interventions. We present a concise review of the available literature on this subject, with a specific focus on indications and outcomes within the military and young athletic population.

Early Complication Rates Are Equivalent Between Isolated Cartilage Restoration and Concomitant Cartilage Restoration and Osteotomy of the Knee

OBJECTIVE

Realignment osteotomy performed concomitantly with cartilage restoration typically requires early restricted weightbearing and can add significant morbidity, potentially leading to an increased risk of early perioperative complications. The purpose of this study was to compare the 30-day complication rates after isolated cartilage restoration (ICR) versus concomitant cartilage restoration and osteotomy (CRO) using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database.

DESIGN

NSQIP registries between 2006 and 2019 were queried using Current Procedural Terminology codes to identify patients undergoing ICR (autologous chondrocyte implantation, osteochondral autograft transfer, or osteochondral allograft transplantation) and CRO (with concomitant high tibial osteotomy, distal femoral osteotomy, and/or tibial tubercle osteotomy). Complications rates between treatment groups were compared using multivariate logistic regression analyses adjusted for sex, age, steroid use, and respiratory status.

RESULTS

A total of 773 ICR and 97 CRO surgical procedures were identified. Mean patient ages were 35.9 years for the ICR group and 31.2 years for the CRO group. Operative time was significantly longer in the CRO group (170.8 min) compared with the ICR group (97.8 min). Multivariate analysis demonstrated no significant differences in rates of PE, VTE, and all-cause readmission between the ICR and CRO groups. No events of wound disruption, SSI and reoperation were found in the CRO group, while the ICR group was characterized by low rates of wound disruption, reoperation, and SSI (<1.1%).

CONCLUSIONS

These findings further support concomitant osteotomy with cartilage restoration when appropriate and aid surgeons in the preoperative counseling of patients undergoing cartilage restoration treatment.

Occupational and Functional Outcomes following Patellofemoral Arthroplasty in U.S. Military Servicemembers

The functional outcomes in patients undergoing patellofemoral arthroplasty (PFA) with high occupational demands have not been fully examined. This study assessed return to work and conversion to TKA rates following PFA in a young, military cohort. Patient demographics, pain scores, and surgical information were retrospectively collected for all active-duty military members who underwent PFA over a 4-year period. The data were then analyzed to calculate return to work, conversion to TKA, and perioperative complications rates. A total of 48 servicemembers with 60 total PFAs (36 unilateral, 12 bilateral) were included, with a mean follow up of 2.2 years. At the final follow-up, 83% of servicemembers returned to military service or completed their service obligation after PFA. Conversion to TKA occurred in three (6.2%) patients at an average of 2.4 years after PFA, resulting in a PFA annual revision rate of 2.3%. The mean numeric rating scale for pain improved from 4.9 ± 2.6 at baseline to 2.5 ± 2.0 postoperatively (p < 0.001). Servicemembers with at least one prior ipsilateral knee procedure had a significantly decreased odds ratio (OR) for both occupational outcome failure (OR, 0.03; 95% confidence interval [CI], 0-0.29) and overall failure (OR, 0.13; 95% CI, 0.02-0.78). At an average of 2 years following PFA, 83% of military members returned to duty, with a low rate of revision to TKA. Prior ipsilateral knee procedure decreased the probability of medical separation. LEVEL OF EVIDENCE:  IV.

Early Postoperative Complications and Associated Variables After Tibial Tubercle Osteotomy: A 15-Year Experience From a Single Academic Institution

Background

Tibial tubercle osteotomy (TTO) is a well-established surgical treatment option for patients with patellofemoral disorders.

Purpose

To determine the rate of early (≤90 day) postoperative complications after TTO and variables related to postoperative complications.

Study Design

Case series; Level of evidence, 4.

Methods

Patients who underwent TTO at a single academic institution within a 15-year period (2008-2022) were identified. All patients with a minimum 90-day follow-up were considered for study inclusion. Exclusion criteria were age younger than 14 years and revision surgery. Patient characteristics, surgical history, and concomitant procedures were identified, and risk factor analysis was performed to identify variables associated with early postoperative complications.

Results

A total of 344 knees in 313 patients met eligibility criteria and were included in the final analysis. One intraoperative complication (0.3%), a premature closure of the incision before repair of the vastus medialis, was identified. There were 141 postoperative complications (138 surgical, 3 medical) in 118 patients for a complication rate of 34.3%. The most common complications were stiffness requiring a nonstandard-of-care intervention (16.3%), superficial wound infection/wound dehiscence (8.1%), and hemarthrosis/effusion requiring aspiration (5.8%). Patients experiencing postoperative complications were older (mean difference, 3.49 years; 95% CI, 1.26-5.73 years; P = .002), had a higher mean Charlson Comorbidity Index (mean difference, 0.26; 95% CI, 0.08-0.45; P = .006), and were more likely to be current smokers (P = .015) compared with patients with no complications. Inpatient surgery (defined as surgery in a hospital setting with at least 1 overnight stay) was associated with postoperative complications (odds ratio [OR], 2.29; 95% CI, 1.39-3.77; P = .001); this association remained significant generation of a multivariate model (OR, 2.07; 95% CI, 1.19-3.58; P = .010). Previous surgery on the ipsilateral knee (P < .001) and concomitant autologous chondrocyte implantation (P = .046) were also associated with postoperative complications.

Conclusion

The study findings indicated a low intraoperative complication rate (0.3%) and a relatively high early postoperative (≤90 day) complication rate (34.3%) after TTO. Variables associated with postoperative complications included greater age, higher Charlson Comorbidity Index, surgery in an inpatient setting, previous surgery on the ipsilateral knee, and concomitant autologous chondrocyte implantation.

Predicting Postoperative Injury and Military Discharge Status After Knee Surgery in the US Army

BACKGROUND

Researchers have assessed postoperative injury or disability predictors in the military setting but typically focused on 1 type of surgical procedure at a time, used relatively small sample sizes, or investigated mixed cohorts with civilian populations.

PURPOSE

To identify the relationship between baseline variables and injury incidence or military discharge status in US Army soldiers after knee surgery.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were obtained from a repository containing personnel, performance, and medical records for all active-duty US Army soldiers. Multivariate logistic regressions were used to estimate the effects of numerous variables on postoperative injury or on medical discharge. Variable selection and model validation were conducted using the k-fold method.

RESULTS

A total of 7567 soldiers underwent knee surgery between 2017 and 2019. Meniscal procedures were the most common type of surgery (39%), and approximately 71% of the cohort had a postoperative injury. Significant predictors for sustaining a postoperative injury included having a previous nonknee injury (odds ratio [OR], 1.5), female sex (OR, 1.3), and Black race (OR, 1.2). Within 4 years after surgery, 17% of soldiers were discharged from the military because of knee-related disability. Significant predictors for discharge from duty included enlisted rank (OR, 2.3), recent fitness test failure (OR, 1.9), number of previous knee surgeries (OR, 1.7), and having a previous nonknee injury (OR, 1.6).

CONCLUSION

After knee surgery, nearly three-fourths of the soldiers in this cohort sustained a postoperative injury and almost one-fifth of soldiers were medically discharged from the military within 4 years. This study identified variables that indicate statistically increased risk for these postoperative outcomes and highlighted potentially modifiable factors.

Patellofemoral articular cartilage damage is associated with poorer patient-reported outcomes following isolated medial patellofemoral ligament reconstruction

PURPOSE

The purpose of this study was to investigate the impact of articular cartilage damage on outcomes following medial patellofemoral ligament (MPFL) reconstruction.

METHODS

Record review identified 160 patients who underwent isolated MPFL reconstruction at a single institution between 2008 and 2016. Patient demographics, patellofemoral articular cartilage status at surgery, and patient anatomical measures from imaging were obtained via chart review. Patients were contacted and outcomes assessed through collection of Norwich Patellar Instability (NPI) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Marx activity score as well as an assessment for recurrent patellar dislocation. Outcomes of patients with grade 0-II patellofemoral cartilage damage were compared to those of patients with grade III-IV cartilage damage.

RESULTS

One hundred twenty-two patients (76%) with a minimum of one year follow-up were contacted at a mean of 4.8 years post-operatively. A total of 63 patients (52%) had grade III or IV patellofemoral chondral damage at the time of surgery. The majority of the defects was on the medial patella (46 patients-72%) and the mean patellar defect size was 2.8 cm². Among 93 patients who completed patient-reported outcome scores, the 52 with grade III or IV chondral damage reported a significantly poorer KOOS Quality of Life than the 44 patients with grade 0 to II chondral damage (p = 0.041), controlling for patient age, sex, BMI, and anatomical factors.

CONCLUSION

Patients with grade III or IV articular cartilage damage of the patellofemoral joint at the time of MPFL reconstruction demonstrated poorer KOOS knee-related quality of life than patients without grade III or IV articular cartilage damage at a mean of 4.8 years following isolated MPFL reconstruction.

LEVEL OF EVIDENCE

Level II.

Senior Military Rank Is Associated With Higher Rates of Return to Running and Unrestricted Activity Among Military Servicemembers After Surgical Repair of Patellar Tendon Rupture at 1-Year Follow-up

Purpose

To evaluate 1-year outcomes in active-duty servicemembers who underwent patellar tendon rupture repair and to identify baseline variables associated with return to activity.

Methods

We performed a retrospective review of all active-duty servicemembers undergoing primary patellar tendon rupture repair between 2009 and 2014. All patients had a minimum 12-month follow-up. Demographic variables were recorded, as well as ability to return to impact activities and remain on active-duty status. Rates of recurrent rupture and revision surgery were identified. Univariate analysis was performed to assess relations between outcomes and baseline variables.

Results

A total of 123 patients met the inclusion criteria (average age, 33.5 ± 6.6 years; 99% male patients) with a mean follow-up period of 4.3 ± 2.2 years. Whereas 67.4% of patients returned to running at an average of 8.3 months from index surgery, only 42.4% of patients resumed unrestricted occupational function. Higher rates of return to running were observed among patients with senior military rank (P = .046). Senior military rank was also associated with a higher rate of return to unrestricted active-duty status (P = .006). Logistic regression analysis showed an association between postoperative pain (odds ratio [OR], 0.684; 95% confidence interval [CI], 0.56-0.84; P < .001) and return to running, between postoperative pain (OR, 0.77; 95% CI, 0.60-0.98; P = .033) and return to active duty, and between rank (OR, 2.06; 95% CI, 1.04-4.07; P = .037) and return to active duty. Patients who sustained injuries during deployment had a higher rate of recurrent rupture (26.1% vs 9.3%, P = .028).

Conclusions

At 1-year follow-up, approximately two-thirds of military servicemembers undergoing primary patellar tendon repair had returned to running after surgery, whereas fewer than one-half returned to full military duty. Younger age and more senior military rank were associated with higher rates of return to running. Additionally, servicemembers of higher rank, particularly officers, had statistically higher rates of return to unrestricted activity.

Level of Evidence

Level IV, therapeutic case series.

Utilization of Autologous Chondrocyte Implantation in the Knee is Increasing While Reoperation Rates Are Decreasing Despite Increasing Preoperative Comorbidities

PURPOSE

The primary purpose of this study was to assess the use of autologous chondrocyte implantation (ACI) procedures in the knee during last decade, and the secondary aims of the study were to determine reoperation rates after ACI and to identify associated risk factors.

METHODS

A retrospective cohort study from 2010-2020 was performed using the PearlDiver database. The database was queried for the Current Procedural Terminology (CPT) code for ACI performed in any knee location, including the patellofemoral and tibiofemoral joints. Reoperation was defined as interventional knee procedures or total knee arthroplasty after ACI. Reoperations were identified using CPT and International Classification of Diseases codes. Univariate and multivariate logistic regression were used to identify risk factors for reoperation. Significance was defined as P < .05.

RESULTS

Among the 2010 patients included in this study, there were 90-day and overall reoperation rates of 2.24% and 30.4%, respectively, with an average follow up of 4.8 ± 3.3 years. The most common reoperations included chondroplasty, meniscectomy, and microfracture. There was an increased rate of ACI performed from 2017-2019 (5.53/100,000) compared to 2014-2016 (4.16/100,000; P < .001). ACI surgeries performed in 2017-2019 were associated with decreased risk of reoperation within 2 years relative to 2014-2016 (odds ratio [OR] = 0.70; 95% confidence interval [CI], 0.52-0.94; P = .019). In the entire ACI cohort, older age (OR = 1.07; 95% CI, 1.05-1.09; P < .001) and tobacco use (OR = 2.13; 95% CI, 1.06-3.94; P = .022) were associated with increased risk of conversion to arthroplasty. Male sex was associated with decreased overall reoperation rates (OR = 0.73; 95% CI, 0.60-0.89; P = .002).

CONCLUSIONS

There has been increasing use of ACI in the knee with decreased risk of reoperation since 2017 and the introduction of matrix-associated autologous chondrocyte implantation. Older age and tobacco use were predictors of increased risk of conversion to arthroplasty. Male sex was associated with decreased risk of reoperation.

LEVEL OF EVIDENCE

Level IV, retrospective cohort design; database study.

Good healing potential of patellar chondral defects after all-arthroscopic autologous chondrocyte implantation with spheroids: a second-look arthroscopic assessment

PURPOSE

To report second-look arthroscopic assessment after all-arthroscopic autologous chondrocyte implantation (ACI) for articular cartilage defects at the patella.

METHODS

A second-look arthroscopy after all-arthroscopic ACI using chondrospheres^® (ACT3D) was performed in 30 patients with 30 full-thickness retropatellar cartilage defects. The mean time from ACI to second-look arthroscopy was 14.9 ± 16.3 (6-71) months. The quality of cartilage regeneration was evaluated by the International Cartilage-Repair Score (ICRS)-Cartilage Repair Assessment (CRA).

RESULTS

Eleven lesions (36.7%) were classified as CRA grade I (normal) and 19 lesions (63.3%) as grade II (nearly normal). Concerning the degree of defect repair, 25 lesions (83.3%) were repaired up to the height of the surrounding articular retropatellar cartilage. Five lesions (16.7%) showed 75% repair of defect depth. The border zone was completely integrated into the surrounding articular cartilage shoulder in 28 lesions (93.3%) and demarcated within 1 mm in 2 lesions (6.7%). Macroscopically and by probing, 12 lesions (40%) had intact smooth surface, 17 lesions (56.7%) had fibrillated surface and 1 lesion (3.3%) had small, scattered fissures. A negative correlation was found between the overall repair assessment score and the defect size (r² = - 0.430, p = 0.046) and between integration into border zone and defect size (r² = - 0.340, p = 0.045). A positive correlation was found between macroscopic appearance and age (r² =  + 0.384, p = 0.036).

CONCLUSIONS

All-arthroscopic ACI using chondrospheres^® (ACT3D) for full-thickness retropatellar articular cartilage defects proved to be reproducible and reliable. The advantage of the procedure is that it is minimal invasive. Arthroscopic second-look demonstrated a high grade of normal or nearly normal cartilage regeneration. Although statistically significant differences were not observed, larger defect size and younger age may compromise the result of overall repair.

LEVEL OF EVIDENCE

III.

Factors correlating with patients' satisfaction after undergoing cartilage repair surgery-data from the German Cartilage Registry (KnorpelRegister DGOU)

Subjective patient satisfaction is the most relevant parameter for assessing the success of treatment after orthopaedic surgery. The aim of the present study was to correlate patient-reported outcome parameters (i.e., absolute KOOS, KOOS increase) and revision-free survival with patient’s satisfaction. Furthermore, the study aimed on the identification of pre-operative factors that are associated with patient’s satisfaction after the surgery.

For the present study, 6305 consecutive patients from the German Cartilage Registry (KnorpelRegister DGOU) were analyzed. Patient characteristics and outcome were correlated with patients’ satisfaction after a follow-up of three years by Spearman correlation. P values < 0.05 were considered statistically significant.

Mean age was 37 ± 12.5 years, 59.7% patients were male, and 40.3% female. Most patients (46.7%) were treated with an autologous chondrocyte implantation (ACI). The strongest correlation of subjective satisfaction and the subscore quality of life (r = 0.682; p < 0.001) was found, whereas the post-operative increase in KOOS from the pre-operative value showed only a moderate correlation (r = 0.520; p < 0.001). There was also a significant correlation with the absolute KOOS value (r = 0.678; p < 0.001), the subscores pain (r = 0.652; p < 0.001), quality of life (r = 0.682; p < 0.001), and sports (r = 0.633; p < 0.001), whereas symptoms (r = 0.504, p < 0.001) and activities of daily life (r = 0.601; p < 0.001) showed a weaker correlation. Pain also correlated highly significant with the patient satisfaction 24 months after surgery (r =  − 0.651, p < 0.001). The correlation between satisfaction after the 2nd and 3rd year (r = 0.727; p < 0.001) is stronger than correlation after six months and three years (r = 0.422, p < 0.001). All pre-operative parameters show a very weak correlation (r < 0.1).

The use of standardized measuring instruments (KOOS and Pain) is a relevant outcome parameter in science and clinical practice, whereas absolute values represent satisfaction better than the individual increase. The subscores “pain,” “quality of life,” and “sports” represent satisfaction better than the subscores “symptoms” and “activity of daily life.” Early satisfaction has only a moderate predictive value for satisfaction after 3 years, which is of great practical relevance in particular for the assessment of potential treatment failures. It is remarkable to note that a revision surgery is only very mildly associated with increased dissatisfaction. Pre-operative factors are not reliable prediction factors for post-operative patient satisfaction.

Return to Work Following Tibial Tubercle Osteotomy for Patellofemoral Osteoarthritis and Pain

PURPOSE

To evaluate the ability of patients to return to work following anteromedialization (AMZ) tibial tubercle osteotomy (TTO) due to isolated patellofemoral osteoarthritis or pain.

METHODS

Consecutive patients undergoing AMZ TTO were reviewed retrospectively at a minimum of 1 year postoperatively. Patients completed a subjective work questionnaire, a visual analog scale for pain, as well as a Kujala questionnaire and satisfaction questionnaire.

RESULTS

Fifty-seven patients (61 knees; average age: 32.7 ± 9.6 years) were contacted at an average follow-up of 4.86 ± 2.84 years postoperatively. The preoperative Kujala score improved from 55.7 ± 17.8 to 84.6 ± 15.8 at final follow-up (P < 0.001). Thirty-seven patients (64.9%) were employed within 3 years prior to surgery and 34 patients (91.9%) were able to return to work by 2.8 ± 2.6 months postoperatively. However, only 27 patients (73.0%) of patients were able to return to the same level of occupational intensity. Patients who held sedentary, light-, medium-, or high-intensity occupations were able to return to work at a rate of 100.0%, 93.8%, 77.8%, and 100.0% by 2.2 months, 3.0 months, 3.1 months, and 4.0 months, postoperatively. No patients underwent revision TTO or conversion to arthroplasty by the time of final follow-up.

CONCLUSION

In patients with focal patellofemoral osteoarthritis or pain, AMZ TTO provides a high rate of return to work (91.9%) by 2.8 ± 2.6 months postoperatively. Patients with higher intensity occupations may take longer to return to work than those with less physically demanding occupations.

LEVEL OF EVIDENCE

III.

Concomitant Osteotomy Reduces Risk of Reoperation Following Cartilage Restoration Procedures of the Knee: A Matched Cohort Analysis

OBJECTIVE

The objective of this study is to compare the (1) reoperation rates, (2) 30-day complication rates, and (3) cost differences between patients undergoing isolated autologous chondrocyte implantation (ACI) or osteochondral allograft transplantation (OCA) procedures alone versus patients with concomitant osteotomy.

STUDY DESIGN

Retrospective cohort study, level III.

DESIGN

Patients who underwent knee ACI (Current Procedural Terminology [CPT] 27412) or OCA (CPT 27415) with minimum 2-year follow-up were queried from a national insurance database. Resulting cohorts of patients that underwent ACI and OCA were then divided into patients who underwent isolated cartilage restoration procedure and patients who underwent concomitant osteotomy (CPT 27457, 27450, 27418). Reoperation was defined by ipsilateral knee procedure after the index surgery. The 30-day postoperative complication rates were assessed using ICD-9-CM codes. The cost per patient was calculated.

RESULTS

A total of 1,113 patients (402 ACI, 67 ACI + osteotomy, 552 OCA, 92 OCA + osteotomy) were included (mean follow-up of 39.0 months). Reoperation rate was significantly higher after isolated ACI or OCA compared to ACI or OCA plus concomitant osteotomy (ACI 68.7% vs. ACI + osteotomy 23.9%; OCA 34.8% vs. OCA + osteotomy 16.3%). Overall complication rates were similar between isolated ACI (3.0%) and ACI + osteotomy (4.5%) groups and OCA (2.5%) and OCA + osteotomy (3.3%) groups. Payments were significantly higher in the osteotomy groups at day of surgery and 9 months compared to isolated ACI or OCA, but costs were similar by 2 years postoperatively.

CONCLUSIONS

Concomitant osteotomy at the time of index ACI or OCA procedure significantly reduces the risk of reoperation with a similar rate of complications and similar overall costs compared with isolated ACI or OCA.

Does Gender Influence Outcome in Cartilage Repair Surgery? An Analysis of 4,968 Consecutive Patients from the German Cartilage Registry (Knorpel Register DGOU)

The goal was to examine gender differences of patient characteristics and outcome after cartilage repair based on a collective of nearly 5,000 patients. Patient characteristics, accompanying therapies, and outcome (Knee Injury and Osteoarthritis Outcome Score [KOOS], reoperations, patient satisfaction) of 4,986 patients of the German cartilage register DGOU were assessed by t test for possible gender differences. P values <0.05 were considered statistically significant. Women were older than men (38.07 ± 12.54 vs. 26.94 ± 12.394 years, P = 0.002), more often preoperated (0.30 ± 0.63 vs. 0.24 ± 0.55, P = 0.001), and had a longer symptom duration (25.22 ± 41.20 vs. 20.67 ± 35.32 months, P < 0.001). Men had greater mean leg axis malalignment than women (3.24° ± 3.26° vs. 2.67° ± 3.06°, P < 0.001), less favorable meniscal status (P = 0.001), worse defect stage (P = 0.006), and a more severely damaged corresponding articular surface (P = 0.042). At baseline (59.84 ± 17.49 vs. 52.10 ± 17.77, P < 0.001), after 6 months (72.83 ± 15.56 vs. 66.56 ± 17.66, P < 0.001), after 12 months (77.88 ± 15.95 vs. 73.07 ± 18.12, P < 0.001), and after 24 months (79.311 ± 15.94 vs. 74.39 ± 18.81, P < 0.001), men had better absolute KOOS values, but women had better relative KOOS increases 6 months (14.59 ± 17.31 vs. 12.49 ± 16.3, P = 0.005) as well as 12 months postoperatively (20.27 ± 18.6 vs. 17.34 ± 17.79, P = 0.001) compared with preoperatively, although 12 and 24 months postoperatively they were subjectively less satisfied with the outcome (P < 0.001) and had a higher reintervention rate at 24 months (0.17 ± 0.38 vs. 0.12 ± 0.33, P = 0.008). In summary, the present work shows specific gender differences in terms of patient characteristics, defect etiology, defect localization, concomitant therapy, and the choice of cartilage repair procedure. Unexpectedly, contrary to the established scientific opinion, it could be demonstrated that women show relatively better postoperative KOOS increases, despite a higher revision rate and higher subjective dissatisfaction.

Comparison of Autologous Chondrocyte Implantation and Osteochondral Allograft Transplantation of the Knee in a Large Insurance Database: Reoperation Rate, Complications, and Cost Analysis

OBJECTIVE

To compare (1) the reoperation rates, (2) risk factors for reoperation, (3) 30-day complication rates, and (4) cost differences between autologous chondrocyte implantation (ACI) and osteochondral allograft transplantation (OCA) of the knee in a large insurance database.

DESIGN

Subjects who underwent knee ACI (Current Procedural Terminology [CPT] code 27412) or OCA (CPT code 27415) with minimum 2-year follow-up were queried from a national insurance database. Reoperation was defined by ipsilateral knee procedure after index surgery. Multivariate logistic regression models were built to determine the effect of independent variables (age, sex, tobacco use, obesity, diabetes, and concomitant osteotomy) on reoperation rates. The 30-day complication rates were assessed using ICD-9-CM codes. The cost of the procedures per patient was calculated. Statistical comparisons were made. All P values were reported with significance set at P < 0.05.

RESULTS

A total of 909 subjects (315 ACI and 594 OCA) were included (mean follow-up 39.2 months). There was a significantly higher reoperation rate after index ACI compared with OCA (67.6% vs. 40.4%, P < 0.0001). Concomitant osteotomy at the time of index procedure significantly reduced the risk for reoperation in both groups (odds ratio [OR] 0.2, P < 0.0001 and OR 0.2, P = 0.009). The complication rates were similar between ACI (1.6%) and OCA (1.2%) groups (P = 0.24). Day of surgery payments were significantly higher after ACI compared with OCA (P = 0.013).

CONCLUSIONS

Autologous chondrocyte implantation had significantly higher reoperation rates and cost with similar complication rates compared with OCA. Concomitant osteotomy significantly reduced the risk for reoperation in both groups.

Comparison of Clinical Outcome following Cartilage Repair for Patients with Underlying Varus Deformity with or without Additional High Tibial Osteotomy: A Propensity Score-Matched Study Based on the German Cartilage Registry (KnorpelRegister DGOU)

BACKGROUND

Even though realignment procedures have gained popularity as concomitant techniques in cartilage repair approaches with underlying malalignment, the clinical efficacy has not been proven to full extent.

METHODS

Out of 5474 patients from the German Cartilage Registry, 788 patients with focal cartilage defects on the medial femoral condyle having received either no accompanying surgery or high tibial osteotomy (HTO) were identified. After a 1:1 propensity score matching, outcome of 440 patients was evaluated using KOOS (Knee Injury and Osteoarthritis Outcome Score), VAS (visual analogue scale), and satisfaction during the 3-year follow-up.

RESULTS

Patients having received a concomitant HTO had significantly higher postoperative KOOS values (12 months: 67.26 ± 15.69 vs.75.10 ± 16.12, P = 0.001; 24 months: 67.14 ± 23.85 vs. 77.11 ± 16.50, P = 0.010; 36 months: 74.40 ± 16.57 vs. 81.75 ± 14.22, P = 0.023) and lower pain levels (6 months: 3.43 ± 2.18 vs. 2.89 ± 2.15, P = 0.009; 12 months: 3.64 ± 2.20 vs. 2.17 ± 1.96, P < 0.001; 24 months: 4.20 ± 3.12 vs. 2.94 ± 2.45, P = 0.005; 36 months: 3.20 ± 2.18 vs. 2.02 ± 1.98, P = 0.003). One and 3 years postoperatively, concomitant HTO led to significantly higher satisfaction in patients. These advantages of accompanying HTO were also seen in the group of patients with a varus deformity of 5° or more, in which pain levels without concomitant HTO even increased during the 3-year follow-up.

CONCLUSION

The results of the present study underline the importance and safety of concomitant HTO in patients with cartilage defects and varus deformity. HTO should therefore be considered and recommended generously in patients with focal cartilage defects of the medial femoral condyle and varus deformity.

Cartilage Restoration of Bipolar Lesions Within the Patellofemoral Joint Delays Need for Arthroplasty: A Systematic Review of Rates of Failure

Purpose

The purpose of the present review is to systematically review the available literature for failure rates and complications of cartilage restoration of bipolar chondral defects in the patellofemoral (PF) joint to assess the ability to treat these lesions without arthroplasty.

Methods

PubMed and MEDLINE databases were queried between 2000 to 2020 using the keywords "osteochondral" and "knee" and "microfracture," "autologous chondrocyte implantation (ACI)," or "transplantation." Patient selection included patients with bipolar chondral lesions of the patellofemoral joint that were treated with cartilage restoration procedures. Treatment of PF joints were reviewed for surgical indications/technique, rates of failure, defect characteristics, and time to failure. For the purposes of this study, failure was defined by each individual author on their respective studies.

Results

After screening 1,295 articles, there were 8 publications analyzed quantitatively and 10 articles analyzed both quantitatively and qualitatively. A total of 249 knees involved bipolar lesions of the patellofemoral joint. The weighted average age was 36.5 ± 10.4 years, and weighted average follow-up was 89.0 ± 31.7 months. There were failures in 0% to 50% of cases, revision procedures in 0% to 10% of cases, conversion to arthroplasty in in 0% to 50% of cases, and unsatisfactory outcome without revision in 0% to 8.3% of cases. The range in average failure rate was 0% to 50.0% (I² = 68.0%), whereas the range in average time to failure was 2.9 to 6.8 years (I² = 79.0%).

Conclusion

From the available data, established cartilage restoration procedures may provide favorable patient-reported function, avoidance of secondary surgery, and joint preservation in at least 80% of patients at short- to mid-term follow-up.

Level of Evidence

Level IV, systematic review of Level IV studies.

Use of MACI (Autologous Cultured Chondrocytes on Porcine Collagen Membrane) in the United States: Preliminary Experience

Background

In December 2016, MACI (autologous cultured chondrocytes on porcine collagen membrane) received approval from the US Food and Drug Administration for the treatment of symptomatic articular cartilage defects of the knee with or without bone involvement in adults.

Purpose

To describe the cartilage defects and patient characteristics for 1000 adult patients treated with MACI for knee cartilage repair in the United States.

Study Design

Case series; Level of evidence, 4.

Methods

Data collected by Vericel for adult patients treated for articular cartilage defects of the knee were reconciled and summarized. Data were collected for 1000 consecutive patients starting on July 1, 2017, when Carticel (the prior generation of autologous cultured chondrocytes) was no longer available. Patient names were removed for confidentiality, and patients were identified by MACI lot number and surgery date. Safety data were derived from the pharmacovigilance database. Patient demographics, cartilage defect characteristics, concomitant surgical procedures, and adverse events were summarized with descriptive statistics.

Results

A total of 1000 adults and 1010 knee joints were implanted with MACI by 372 surgeons. The male (49.6%)-to-female (50.4%) ratio was evenly split, and the mean age was 34.0 years. The majority of patients (68.1%) had a single cartilage defect treated, and the mean treated defect size was 4.7 cm². The mean total treated lesion size, including multiple defects, was 5.8 cm². The patella was the most commonly treated joint surface (32.7%), followed by the medial femoral condyle (31.3%). Most patients (92.4%) had concomitant surgical procedures at the time of cartilage biopsy acquisition. The most common concomitant procedures at the time of biopsy procurement included cartilage debridement (83.7%) and meniscal resection (11.3%). The most common planned concomitant surgeries at the time of MACI implantation were anterior tibial tubercleplasty (7.8%) and reconstruction of dislocating patella (5.5%). Few patients (2.6%) had adverse events.

Conclusion

Patient age and mean total MACI-treated defect size in the United States are similar to the findings of the pivotal European SUMMIT (Superiority of MACI Implant Versus Microfracture Treatment) trial and other studies from outside the United States. Treatment of multiple cartilage defects is more frequent in the United States than elsewhere.

Patellofemoral Cartilage Restoration: A Systematic Review and Meta-analysis of Clinical Outcomes

BACKGROUND

Many surgical options for treating patellofemoral (PF) cartilage lesions are available but with limited evidence comparing their results.

PURPOSE

To determine and compare outcomes of PF cartilage restoration techniques.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines were followed by utilizing the PubMed, EMBASE, and Cochrane Library databases. Inclusion criteria were clinical studies in the English language, patient-reported outcomes after PF cartilage restoration surgery, and >12 months' follow-up. Quality assessment was performed with the Coleman Methodology Score. Techniques were grouped as osteochondral allograft transplantation (OCA), osteochondral autograft transfer (OAT), chondrocyte cell-based therapy, bone marrow-based therapy, and scaffolds.

RESULTS

A total of 59 articles were included. The mean Coleman Methodology Score was 71.8. There were 1937 lesions (1077 patellar, 390 trochlear, and 172 bipolar; 298 unspecified). The frequency of the procedures was as follows, in descending order: chondrocyte cell-based therapy (65.7%), bone marrow-based therapy (17.2%), OAT (8%), OCA (6.6%), and scaffolds (2.2%). When compared with the overall pooled lesion size (3.9 cm²; 95% CI, 3.5-4.3 cm²), scaffold (2.2 cm²; 95% CI, 1.8-2.5 cm²) and OAT (1.5 cm²; 95% CI, 1.1-1.9 cm²) lesions were smaller (P < .001), while chondrocyte cell-based therapy lesions were larger (4.7 cm²; 95% CI, 4.1-5.3 cm²; P = .039). Overall, the instability pool was 11.9%, and the anatomic risk factors pool was 32.1%. Statistically significant improvement was observed on at least 1 patient-reported outcome in chondrocyte cell-based therapy (83%), OAT (78%), OCA (71%), bone marrow-based therapy (64%), and scaffolds (50%). There were no significant differences between any group and the overall pooled change in International Knee Documentation Committee score (30.2; 95% CI, 27.4-32.9) and Lysholm score (25.2; 95% CI, 16.9-33.5). There were no significant differences between any group and the overall pooled rate in minor complication rate (7.6%; 95% CI, 4.7%-11.9%) and major complication rate (8.3%; 95% CI, 5.7%-12.0%); however, OCA had a significantly greater failure rate (22.7%; 95% CI, 14.6%-33.4%) as compared with the overall rate (6.8%; 95% CI, 4.7%-9.5%).

CONCLUSION

PF cartilage restoration leads to improved clinical outcomes, with low rates of minor and major complications. There was no difference among techniques; however, failures were higher with OCA.

Functional Outcomes After Isolated and Combined Posterior Cruciate Ligament Reconstruction in a Military Population

Background:

The rates of return to full activity, persistent disability, complications, and surgical revisions after operative management of posterior cruciate ligament (PCL) tears in a physically active population have not been reported.

Purpose:

To evaluate the clinical outcomes of active military patients with symptomatic PCL tears who underwent surgical reconstruction and compare outcomes between isolated PCL and multiligament injuries.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Individuals undergoing surgical reconstruction of the PCL (Current Procedural Terminology code 29889) were isolated from the Military Health System Management Analysis and Reporting Tool between fiscal years 2005 and 2010. Demographic variables and rates of postoperative complications, activity limitations, rates of revision surgery, physical disability ratings, and ultimate medical discharge were recorded from the electronic medical record and US Army Physical Disability Agency database.

Results:

A total of 182 patients underwent 193 surgeries, including 118 isolated PCL reconstructions and 75 multiligament knee reconstructions, with an average follow-up of 19.5 months. There were 174 primary procedures and 19 revision reconstructions. The mean ± SD patient age was 28.4 ± 7.2 years, with males comprising 96.2% of patients. The overall surgical complication rate was 12.4%, with a significantly higher rate in multiligament knee reconstructions compared with isolated PCL reconstructions (18.7% vs 8.5%; P = .045). Overall, 35.1% of patients were discharged from military service due to disability. Rates of discharge were significantly higher in those undergoing surgery at lower volume institutions (those that performed <2 PCL reconstructions per year during the study period) than those at higher volume institutions (41.1% vs 26%; P = .040). The overall revision rate was 10.9%, with no significant difference between the isolated PCL and multiligament knee reconstructions. Of the 103 patients with primary isolated PCL reconstructions, 35% underwent medical discharge for persistent knee complaints, and 12.6% required revision PCL reconstruction. The overall failure rate for primary isolated PCL reconstructions, which includes both revision surgery and knee-related medical discharge from military service, was 42.7%.

Conclusion:

In a physically active, military population, nearly one-third of patients were unable to return to previous level of military function, and 12.6% required revision at short-term follow-up due to persistent instability. Perioperative complication rates were significantly higher among patients with multiligament knee reconstructions.