Derotational distal femoral osteotomy improves subjective function and patellar tracking after medial patellofemoral ligament reconstruction in recurrent patellar dislocation patients with increased femoral anteversion: A systematic review and meta-analysis

PURPOSE

The purpose of this study is to systematically review and quantitatively analyse the clinical outcomes of combined derotational distal femoral osteotomy (D-DFO) and medial patellofemoral ligament reconstruction (MPFL-R) in the treatment of recurrent patellar dislocation (RPD) with increased femoral anteversion angle (FAA).

METHODS

This study was performed in line with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and AMSTAR (Assessing the Methodological Quality Of Systematic Reviews) Guidelines. PubMed, Embase, Web of Science and Cochrane Library databases were searched to identify studies reporting clinical outcomes of combined D-DFO and MPFL-R in RPD patients with increased FAA. Data on patient-reported outcome measures, radiological parameters, patellar tracking as revealed by J-sign and complications were extracted based on the inclusion criteria. The Methodological Index for Non-Randomized Study score was used for quality assessment. Review Manager and R statistical software were used to perform the statistical analysis.

RESULTS

Eleven studies with a total of 569 knees in 553 patients were included. Patients were predominantly female (79%). The weighted mean of FAA decreased from 33.6° to 13.0° (weighted mean difference = 20.59; p < 0.00001) after the combined procedure. Significant improvements (p < 0.00001) were identified in the Lysholm score (weighted mean: 55.5 vs. 80.4), International Knee Documentation Committee (IKDC) score (weighted mean: 52.8 vs. 78.6) and Kujala score (weighted mean: 54.5 vs. 80.6). The incidence of residual J-sign ranged from 14.3% to 38.3% with an overall pooled rate of 28.2% (95% confidence interval = 22.8%-33.6%). The overall redislocation rate was 1.1%. No patients experienced surgical site infection or bone nonunion. Two studies compared the clinical outcomes of MPFL-R with and without D-DFO. Compared with isolated MPFL-R, the combined procedure yielded a better Lysholm score (weighted mean: 84.9 vs. 79.3, p < 0.0001), IKDC score (weighted mean: 84.1 vs. 79.9, p = 0.001), Kujala score (weighted mean: 84.3 vs. 79.4, p < 0.0001) and a lower residual J-sign rate (26/97 [26.8%] vs. 44/105 [41.9%], p = 0.02), respectively.

CONCLUSION

The combination of D-DFO and MPFL-R led to improved clinical outcomes and a low redislocation rate in patients with RPD and increased FAA. Additional D-DFO can achieve more favourable results in subjective function and patellar tracking than isolated MPFL-R in the setting of excessive FAA.

LEVEL OF EVIDENCE

Level IV.

Outcomes After Derotational Distal Femoral Osteotomy for Recurrent Patellar Dislocations With Increased Femoral Anteversion: A Systematic Review and Meta-analysis

Background

An increased femoral anteversion angle (FAA) is a predisposing factor for recurrent patellar dislocations (RPDs), and combined procedures including derotational distal femoral osteotomy (DDFO) have been shown to be good options.

Purpose

To investigate the safety and effectiveness of combined DDFO on clinical and radiological outcomes to treat RPDs with an increased FAA.

Study Design

Systematic review; Level of evidence, 4.

Methods

This review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. We searched 7 databases for articles from inception to March 10, 2023, that reported outcomes after combined DDFO in patients with an RPD and increased FAA. Two reviewers independently extracted data and assessed study quality. Outcomes evaluated were functional scores, redislocation rates, complications, satisfaction, and radiological parameters. A meta-analysis was performed to pool functional scores, with data reported as mean differences (MDs) and 95% confidence intervals (CIs).

Results

Included were 8 studies of 189 knees from 183 patients, with a mean patient age of 22.4 years and a mean follow-up of 33.4 months. The mean preoperative FAA ranged from 31° to 42.70°, and the mean postoperative FAA ranged from 10° to 19.08°. Significant improvements were found in the Kujala score (MD, 26.96 [95% CI, 23.54 to 30.37]), Lysholm score (MD, 26.17 [95% CI, 22.13 to 30.22]), visual analog scale score for pain (MD, -2.61 [95% CI, -3.12 to -2.10]), and Tegner activity score (MD, 1.33 [95% CI, 0.86 to 1.79]). No subluxation or redislocation occurred. The overall complication rate was 10.6%, and most of the complications were pain (60%) and limited knee activity (20%). The overall satisfaction rate was 83.3%. The patellar tilt angle significantly decreased from 40.7° ± 11.9° to 20.5° ± 8.7° and from 26.35° ± 6.86° to 11.65° ± 2.85° in 2 studies.

Conclusion

Combined DDFO was found to be safe and effective for the treatment of RPDs and an increased FAA by addressing both patellar dislocations and torsional malalignment. However, because of the lack of comparisons, it remains to be investigated when DDFO should be combined in such patients.

Clinical and Second-look Arthroscopic Results for Derotational Distal Femoral Osteotomy With Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Dislocation With Increased Femoral Anteversion: A Series of 102 Cases With a Minimum Clinical Follow-up of 2 Years

BACKGROUND

Derotational distal femoral osteotomy (DDFO) has been used to treat patients with recurrent patellar dislocation (RPD) with increased femoral anteversion. However, no study has reported second-look arthroscopic findings in the patellofemoral joint after DDFO.

PURPOSE

To report clinical and second-look arthroscopic outcomes for DDFO with combined medial patellofemoral ligament reconstruction (MPFL-R) in treating RPD with increased femoral anteversion.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From 2015 to 2019, 131 consecutive patients (144 knees) with RPD were treated with combined MPFL-R and DDFO. Patients with a femoral anteversion angle >30° and a minimum 2-year clinical follow-up period were included in the study. Three-dimensional computed tomography was performed to evaluate rotational deformities of the lower leg. Radiographic parameters presenting bony abnormalities associated with RPD were measured. Second-look arthroscopic evaluations were available for 86 knees to assess patellar tracking and chondral lesion changes. Moreover, clinical and radiologic outcomes were assessed pre- and postoperatively at a minimum 2 years.

RESULTS

A total of 102 knees in 92 patients were included in the present study with a mean clinical follow-up of 4.1 years (range, 2.0-5.6 years). Mean ± SD femoral anteversion changed significantly from 34.7°± 7.5° preoperatively to 11.3°± 0.2° postoperatively (P < .001), and mean tibial tubercle-trochlear groove distance decreased significantly from 19.6 ± 3.5 mm preoperatively to 17.4 ± 3.2 mm postoperatively (P < .001). In the majority of knees, at the time of second-look arthroscopic assessment, chondral lesion status remained unchanged at the lateral patellar facet (96%) and trochlear groove (95%); in contrast, chondral damage at the medial patellar facet was aggravated in 9 cases (10%). All functional scores (Tegner, Lysholm, visual analog scale, and Kujala scores) improved significantly at final follow-up. None of the patients experienced redislocation or subluxation after surgery.

CONCLUSION

Chondral lesions in the patellofemoral joint remained unchanged in the majority of cases in second-look arthroscopy after combined MPFL-R and DDFO. Moreover, high-grade trochlear dysplasia and arthroscopic residual patellar maltracking might be associated with cartilaginous deterioration at the medial patellar facet after surgery.

[Short-term effectiveness of derotational distal femoral osteotomy combined with medial patellofemoral ligament reconstruction for recurrent patellar dislocation]

Objective

To investigate the short-term effectiveness of derotational distal femoral osteotomy (DDFO) combined with medial patellofemoral ligament (MPFL) reconstruction in treatment of recurrent patellar dislocation with excessive femoral anteversion angle (FAA≥30°).

Methods

Between June 2017 and August 2019, 17 patients with recurrent patellar dislocation with FAA≥30° were treated with DDFO and MPFL reconstruction. There were 5 males and 12 females, aged 14-22 years, with an average of 17.7 years. The patella dislocated for 2 to 8 times (mean, 3.6 times). The disease duration was 2-7 years (mean, 4.6 years). The patellar apprehension tests were positive. Preoperative pain visual analogue scale (VAS) score, Lysholm score, Tegner score, and Kujala score were 4.2±1.1, 47.8±8.1, 3.6±1.1, and 56.8±5.7, respectively. FAA, mechanical lateral distal femoral angle (mLDFA), lateral patella displacement (LPD), tibial tuberosity-trochlear groove distance (TT-TG) were (34.9±3.4)°, (85.8±3.0)°, (13.7±3.8) mm, and (23.1±2.1) mm, respectively.

Results

All incisions healed by first intention, and there was no complications such as knee stiffness, infection, and re-dislocation of the patella. All patients were followed up 13-25 months, with an average of 17.7 months. The imaging review showed that 1 case of osteotomy did not union, and achieved satisfactory results after the secondary revision and strengthening fixation; the osteotomies of other patients healed completely after 3 to 4 months of operation. The patellar apprehension tests were negative. At last follow-up, the FAA, mLDFA, LPD, and TT-TG were (15.6±2.7)°, (83.0±2.1)°, (5.0±2.6) mm, and (20.5±2.5) mm, respectively; the VAS score, Lysholm score, Tegner score, and Kujala score were 2.4±1.4, 93.4±7.8, 6.8±1.5, and 89.0±8.0, respectively. There were significant differences in the above indicators between pre- and post-operation ( P<0.05).

Conclusion

DDFO combined with MPFL reconstruction for the recurrent patellar dislocation with excessive FAA (≥30°) can achieve good short-term effectiveness, significantly reduce knee pain, and improve function.

Medial Patellofemoral Ligament Reconstruction With or Without Derotational Distal Femoral Osteotomy in Treating Recurrent Patellar Dislocation With Increased Femoral Anteversion: A Retrospective Comparative Study

BACKGROUND

Controversy exists regarding the surgical treatment of recurrent patellar dislocation (RPD) with an increased femoral anteversion angle (FAA). Medial patellofemoral ligament reconstruction (MPFL-R) either alone or combined with derotational distal femoral osteotomy (DDFO) results in favorable clinical outcomes.

PURPOSE

To compare the clinical outcomes of MPFL-R versus MPFL-R with DDFO in treating RPD with increased FAA (>30°).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Between January 2014 and December 2017, 126 patients (135 knees) with RPD and increased FAA (>30°) were surgically treated using MPFL-R with or without DDFO and eligible for this retrospective study. These patients were allocated into 2 groups based on whether an additional DDFO was performed: the DDFO group (MPFL-R + DDFO with or without tibial tubercle transfer; n = 66) and the control group (MPFL-R with or without tibial tubercle transfer; n = 69). Pre- and postoperative patellar stability was measured using stress radiography. Patellar maltracking (J-sign) and patient-reported outcomes (Kujala, International Knee Documentation Committee, Lysholm, and Tegner scores) were evaluated and compared between the 2 groups. Subgroup analysis was performed by stratifying the results in terms of the severity of preoperative patellar maltracking (low-grade vs high-grade J-sign).

RESULTS

A total of 135 knees (126 patients) with a mean follow-up time of 3.7 ± 1.2 years were evaluated in the present study. The rates of postoperative MPFL residual graft laxity and residual J-sign were significantly lower in the DDFO group than in the control group (6% vs 19%, P = .028; 33% vs 54%, P = .018). The DDFO group had significantly higher Kujala (82.3 vs 76.7; P = .001) and Lysholm (83.7 vs 77.7; P = .034) scores than the control group had postoperatively. For patients with a preoperative high-grade J-sign, further subgroup analysis demonstrated that the DDFO group had a significantly lower rate of MPFL residual graft laxity than the control group had (18% vs 57%; P = .029).

CONCLUSION

In this retrospective study, treatment of RPD with increased femoral anteversion using MPFL-R with DDFO yielded more favorable subjective and objective outcomes than did MPFL-R without DDFO, and this circumstance was more remarkable when the patients had a preoperative high-grade J-sign.

A High-Grade J Sign Is More Likely to Yield Higher Postoperative Patellar Laxity and Residual Maltracking in Patients With Recurrent Patellar Dislocation Treated With Derotational Distal Femoral Osteotomy

BACKGROUND

It has been speculated that the patellar J sign may have a negative effect on the clinical outcomes of patients with recurrent patellar dislocation (RPD).

PURPOSE

To (1) evaluate clinical outcomes, postoperative patellar stability, and patellar maltracking correction in patients with RPD treated with derotational distal femoral osteotomy (DDFO) and combined procedures and (2) investigate the influence of J sign severity on the clinical outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Between January 2015 and December 2016, a total of 78 patients (81 knees) with RPD, a positive J sign, and an excessive femoral anteversion angle (FAA; ≥30°) were surgically treated with DDFO and combined procedures. J sign severity was graded according to a previously described classification system (grades 1-3). Routine radiography and computed tomography were performed on every patient to evaluate the patellar height, trochlear dysplasia, genu valgum, tibial tuberosity-trochlear groove distance, patellar lateral tilt angle, and patella-trochlear groove distance. The patellar lateral shift distance during stress radiography was measured preoperatively and postoperatively to quantify medial patellofemoral ligament (MPFL) graft laxity under anesthesia, and "MPFL residual graft laxity" was defined as the patellar ridge surpassing the apex of the lateral femoral trochlea. Patients were evaluated using the Kujala, International Knee Documentation Committee (IKDC), and Lysholm scores preoperatively and postoperatively. Patients were allocated into 3 subgroups in terms of the severity of the J sign: low-grade group 1 (grade 1; n = 19), low-grade group 2 (grade 2; n = 16), and high-grade group (grade 3; n = 12). Subgroup analyses were performed to investigate the influence of a high-grade J sign on the clinical outcomes.

RESULTS

Among the 78 patients (81 knees), 47 patients (47 knees) met the inclusion criteria. The mean follow-up time was 26.1 ± 1.7 months. The mean preoperative and postoperative FAAs were 36.2°± 5.3° and 10.0°± 2.1°, respectively, with a mean correction angle of 26.2°± 5.9°. At the final follow-up, all patient-reported outcomes improved significantly, and subgroup analyses showed that the high-grade group had significantly lower Kujala scores (75.6 vs 85.3 for low-grade group 1 [P < .001] and 83.4 for low-grade group 2 [P = .001]), Lysholm scores (77.6 vs 84.6 for low-grade group 1 [P = .003]), and IKDC scores (78.6 vs 87.3 for low-grade group 1 [P = .001] and 84.3 for low-grade group 2 [P = .033]) than the low-grade groups. The total rate of MPFL residual graft laxity was 8.5% (4/47), and the prevalence of the postoperative residual J sign was 38.3% (18/47). Subgroup analyses showed significant differences between the high-grade group and the 2 low-grade groups with regard to the MPFL residual graft laxity rate (33.3% vs 0.0% for low-grade group 1 [P = .016] and 0.0% for low-grade group 2 [P = .024]), residual J sign rate (91.7% vs 15.8% for low-grade group 1 [P < .001] and 25.0% for low-grade group 2 [P < .001]), and patellar lateral shift distance (14.2 vs 8.1 mm for low-grade group 1 [P = .002] and 8.7 mm for low-grade group 2 [P = .007]).

CONCLUSION

In a group of patients treated for RPD with a positive preoperative J sign and increased FAA (≥30°), patients with a preoperative high-grade J sign had inferior clinical outcomes, more MPFL residual graft laxity, and greater residual patellar maltracking.