The role of medial retinaculum plication versus medial patellofemoral ligament reconstruction in combined procedures for recurrent patellar instability in adults

Arthroscopic-assisted medial retinacular plication through stab wounds using an 18-gauge needle for acute lateral patellar dislocation: Technical note

In lateral patellar dislocation, injuries commonly involve the medial retinaculum and the medial patellofemoral ligament (MPFL). Stabilizing the medial soft tissue is crucial, with options including MPFL repair, reconstruction, or medial retinacular plication. For acute cases, MPFL reconstruction may be overly invasive, leading to donor site morbidity and scarring concerns, especially in young females. The authors propose an arthroscopic-assisted medial retinacular plication technique through stab wounds for acute dislocations, offering the advantage of being less invasive with good cosmetic outcomes.

Patellofemoral instability part 1 (When to operate and soft tissue procedures): State of the art

Patellofemoral instability is usually initially treated non-operatively. Surgery is considered in patients with recurrent patellar dislocation and after a first-time patellar dislocation in the presence of either an associated osteochondral fracture or high risk of recurrence. Stratifying the risk of recurrence includes evaluating risk factors such as age, trochlear dysplasia, contralateral dislocation, and patellar height. Surgery with soft tissue procedures includes restoring the medial patellar restraints and balancing the lateral side of the joint. Reconstruction of the medial patellofemoral ligament is the most frequent way of addressing the medial soft tissues in patients with patellofemoral instability. Meanwhile, lateral tightness can be achieved by lateral retinaculum lengthening or release. Approaching patellofemoral instability in a patient-specific approach, combined with a shared decision-making process with the patient/family, will guide surgeons to the deliver optimal care for the patellar instability patient.

Double-Level Knee Derotational Osteotomy Yields Better Postoperative Outcomes Than Tibial Tubercle Transfer Combined With Medial Patellofemoral Ligament Reconstruction in Patients With Recurrent Patellar Instability and Severe Malrotation

PURPOSE

To assess the postoperative outcomes of double-level knee derotational osteotomy (KDRO) combined with medial patellofemoral ligament reconstruction (MPFLR) and to compare it with tibial tuber transfer (TTT) and MPFLR without derotational osteotomy in patients with recurrent patellar instability and a marked torsional deformity.

METHODS

From March 2020 to December 2021, patients with torsion deformity (combined femoral torsion [FT] and tibial torsion [TTn] ≥30°) were retrospectively included. The minimum follow-up time was 18 months. Patients who received KDRO and MPFLR were categorized as the KDRO group and patients who received a combined TTT and MPFLR were categorized as the control group. Preoperative and postoperative clinical symptoms, patient-reported outcomes (Kujala, visual analog scale, Lysholm, International Knee Documentation Committee, Tegner, and Knee Injury and Osteoarthritis Outcome scores), and imaging parameters (FT, TTn, patellar height, femoral trochlear dysplasia, congruence angle, patellar tilt angle, lateral patellar angle, lateral patellar translation, and tibial tubercle-trochlear groove distance) were analyzed.

RESULTS

In all, 36 patients were included with 18 in KDRO group and 18 in control group. The mean follow-up time was 30 (range 21-39) months. At the latest follow-up, no patient experienced redislocation in either group. Except for the FT and TTn in the control group, postoperative imaging parameters were significantly reduced to the normal range. KDRO group had a lower patellar tilt angle (P = .043, effect size 0.64). All clinical scores in both groups significantly improved postoperatively. The KDRO group had better functional scores than control group except the KOOS daily living activities subscore and the KOOS sports and recreation subscore. More patients in the KDRO group met the minimal clinically important difference for most patient-reported outcomes than the control group. Eight patients (44%) in the control group complained of postoperative anterior knee pain, compared with 1 patient (6%) in the KDRO group (P = .018).

CONCLUSIONS

KDRO combined with MPFLR was associated with better postoperative outcomes than TTT combined with MPFLR in patients with recurrent patellar instability and a torsion deformity.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

The Value of Minimal Clinically Important Difference, Substantial Clinical Benefit, and Patient-Acceptable Symptomatic State for Commonly Used Patient-Reported Outcomes in Recurrent Patellar Instability Patients After Medial Patellofemoral Ligament Reconstruction and Tibial Tubercle Transfer

PURPOSE

To identify the minimal clinically important difference (MCID), substantial clinical benefit (SCB) and patient-acceptable symptomatic state (PASS) for commonly used patient-reported outcomes (PROs) in recurrent patellar instability patients after medial patellofemoral ligament reconstruction (MPFLR) and tibial tubercle transfer (TTT), and to determine the impact of potential prognostic factors on the likelihood of achieving these values.

METHODS

From April 2015 to February 2021, patients who underwent MPFLR and TTT were retrospectively reviewed. PROs included Kujala, Knee Injury and Osteoarthritis Outcome (KOOS), Lysholm, International Knee Documentation Committee (IKDC), and Tegner score. Relevant anchor questions were provided. A distribution- or anchor-based method was adopted to determine the MCID, SCB, and PASS. Minimal detectable change (MDC) was included to confirm the validity. Univariate regression analyses were conducted to determine the potential prognostic factors.

RESULTS

One hundred forty-two patients were included. The MCID were 9.1 (Kujala), 11.1 (Lysholm), 0.9 (Tegner), 9.9 (IKDC), 9.0 (KOOS-Pain), 10.8 (KOOS-Symptoms), 10.0 (KOOS-Activities of Daily Living [ADL]), 17.8 (KOOS-Sports and Recreation [Sports/Rec]), and 12.7 (KOOS-Quality of Life [QoL]). The SCB were 14.5 (Kujala), 12.5 (Lysholm), 1.5 (Tegner), 14.5 (IKDC), 13.9 (KOOS-Pain), 14.3 (KOOS-Symptoms), 18.4 (KOOS-ADL), 47.5 (KOOS-Sports/Rec), and 15.0 (KOOS-QoL). The PASSs were 85.5 (Kujala), 75.5 (Lysholm), 3.5 (Tegner), 73.2 (IKDC), 87.5 (KOOS-Pain), 73.2 (KOOS-Symptoms), 92.0 (KOOS-ADL), 77.5 (KOOS-Sports/Rec), and 53.1 (KOOS-QoL). All SCBs were valid except KOOS-QoL. All MCIDs were valid at the 95% confidence interval (CI) except KOOS scores, the majority of which were valid at the 90% CI. A younger age was an independent prognostic factor of reaching PASS for Lysholm, IKDC, Tegner, and KOOS-ADL score. A higher baseline score was a negative prognostic factor for achieving MCID or SCB but had a slightly positive influence on the achievement of PASS.

CONCLUSIONS

This study established the MCID, SCB, and PASS for commonly used PROs and confirmed their validity in recurrent patellar instability patients after MPFLR and TTT. Younger age and lower baseline scores were prognostic factors of achieving MCID and SCB, whereas patients with higher baseline scores were more likely to report satisfaction.

LEVEL OF EVIDENCE

Level III, retrospective comparative prognostic trial.

Addition of Tibial Tubercle Osteotomy to Combined MPFL Reconstruction and Lateral Retinacular Release not Recommended for Recurrent Patellar Dislocation in Patients with 15 to 20 mm TT-TG

Surgery is the primary treatment for recurrent patellar dislocation. However, there is still a lack of consensus regarding the choice of combined surgical methods due to the complexity of the anatomical factors. This study aimed to investigate the efficacy and radiological changes in medial patellofemoral ligament reconstruction (MPFLR) and lateral retinacular release (LRR) with and without tibial tubercle osteotomy (TTO) for recurrent patellar dislocation in patients with a tibial tubercle-trochlear groove (TT-TG) distance of 15 to 20 mm. Fifty-four patients were enrolled in this retrospective study between 2010 and 2014. The average patient age was 21.6 ± 5.0 years. All patients underwent MPFLR and LRR, and in 18 patients, these procedures were combined with TTO. Patients were evaluated preoperatively and postoperatively for patellar lateral shift, patellar tilt angle, TT-TG distance, Q-angle, Caton-Deschamps index (CDI), Kujala, and Lysholm scores. The minimally clinical important difference was used to compare clinical outcomes between two groups. In the mean follow-up of 82.6 ± 15.9 months, functional scores improved significantly in both groups (p < 0.01). There were no significant differences in postoperative function scores between the two groups (Kujala, p = 0.25, mean difference = 1.5, 95% confidence interval [CI]: -1.4-4.4; Lysholm, p = 0.76, mean difference = -0.6, 95% CI: -5.9-4.7). Additionally, TTO significantly decreased Q-angle (23.6 ± 2.4 vs. 17.4 ± 2.9, p < 0.01), TT-TG (17.1 ± 1.5 vs. 10.4 ± 1.8, p < 0.01), and CDI (1.18 ± 0.12 vs. 1.08 ± 0.07, p < 0.01). Combined MPFLR and LRR with and without TTO are both effective techniques for recurrent patellar dislocation. Additional osteotomy can correct patellar alta and tibial tubercle lateralization. However, given that there were no significant differences in postoperative functional scores or recurrence rate between groups, we may not recommend TTO in addition to MPFLR and LRR in patients with TT-TG of 15 to 20 mm. Long-term and prospective cohort studies are required to assess further outcomes.

Double-Limb Graft Versus Single-Limb Graft Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Dislocation: A Meta-analysis of Randomized Controlled Trials and Cohort Studies

BACKGROUND

The medial patellofemoral ligament (MPFL) is the most important stabilizer of lateral dislocation of the patella. Single-limb (SL) and double-limb (DL) graft MPFL reconstructions have been increasingly used to treat recurrent patellar dislocations, but the clinical efficacy of SL versus DL graft MPFL reconstructions remains controversial owing to the inconsistent conclusions of previous studies.

PURPOSE

This study aimed to compare the clinical outcomes of SL and DL graft MPFL reconstructions for patients with recurrent patellar dislocation by conducting a meta-analysis of randomized controlled trials and cohort studies.

STUDY DESIGN

Meta-analysis; Level of evidence, 3.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were searched for relevant studies. The retrieval time was up to July 25, 2022. Two evaluators independently screened the literature, extracted data, and assessed the methodological quality of the enrolled studies. Meta-analysis was conducted using RevMan 5.4 software.

RESULTS

A total of 4 randomized controlled trials and 3 cohort studies with 451 patients were included. The joint stability and functional scores in both groups improved significantly from baseline. When compared with SL graft reconstruction, DL graft reconstruction provided reduced recurrent instability (P = .01), anterior patella-related pain (P = .02), and patellar lateral shift rate (P = .02). Regarding functional recovery, patients undergoing DL graft reconstruction presented better scores on the Kujala (P < .001), Tegner (P = .009), and International Knee Documentation Committee (IKDC) (P < .001) but similar Lysholm scores as compared with SL graft reconstruction. No statistically significant difference was found between the techniques in the reduction of the patellar tilt angle, complications other than anterior patella-related pain, or postoperative pain.

CONCLUSION

When compared with SL graft MPFL reconstruction, DL graft MPFL reconstruction yielded better outcomes in terms of postoperative recurrent instability, anterior patella-related pain, patellar lateral shift rate, Kujala score, Tegner score, and IKDC score. The amount of high-quality evidence is insufficient, so this conclusion should be interpreted with caution.

Effect of Lower Extremity Torsion on Clinical Outcomes After Medial Patellofemoral Ligament Reconstruction and Tibial Tubercle Transfer for Recurrent Patellofemoral Instability

BACKGROUND

Increased femoral torsion (FT) or tibial torsion (TT) has been suggested to be a potential risk factor for recurrent patellofemoral instability. However, the influence of increased FT or TT on the postoperative clinical outcomes of recurrent patellofemoral instability has rarely been investigated.

PURPOSE

To assess the effect of increased FT or TT on postoperative results in patients with recurrent patellofemoral instability after combined medial patellofemoral ligament reconstruction (MPFLR) and tibial tubercle transfer, along with the influence of other risk factors.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Out of 91 patients, the study's analyses included 86 patients with recurrent patellofemoral instability who were treated with MPFLR and tibial tubercle transfer and enrolled between April 2020 and January 2021. FT and TT were assessed using preoperative computed tomography images. According to the torsion value of FT or TT, patients were categorized into 3 groups for each of FT and TT: group A (<20°), group B (20°-30°), and group C (>30°). Patellar height, femoral trochlear dysplasia, and the tibial tuberosity-trochlear groove (TT-TG) distance were also assessed. Patient-reported outcome scores (Tegner, Kujala, International Knee Documentation Committee [IKDC], Lysholm, and Knee injury and Osteoarthritis Outcome Score [KOOS]) were evaluated pre- and postoperatively. Clinical failure of MPFLR was recorded. Subgroup analysis was conducted to evaluate the effect of increased FT or TT on the postoperative outcomes.

RESULTS

A total of 86 patients were enrolled with a median follow-up time of 25 months. At the final follow-up, all functional scores improved significantly. Patella alta, high-grade trochlear dysplasia, and increased TT-TG distance did not have any significant effect on the postoperative functional scores. Regarding FT, subgroup analysis indicated that all functional scores of group C were lower than those of groups A and B except the KOOS knee-related Quality of Life score. For TT, group C had lower scores than group A for all functional outcomes except Tegner and KOOS Quality of Life and lower scores than group B for Kujala, IKDC, KOOS (Symptoms and Sport and Recreation subscales), Tegner, and Lysholm scores. The comparison between group A and group B, whether for FT or TT, revealed no significant differences.

CONCLUSION

For patients with recurrent patellofemoral instability, increased lower extremity torsion (FT or TT >30°) was associated with inferior postoperative clinical outcomes after combined MPFLR and tibial tubercle transfer.

Surgical treatment of patellar dislocation: A network meta-analysis of randomized control trials and cohort studies

Background

Currently, there are many surgical options for patellar dislocation. The purpose of this study is to perform a network meta-analysis of the randomized controlled trials (RCTs) and cohort studies to determine the better treatment.

Method

We searched the Pubmed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, clinicaltrials.gov and who.int/trialsearch. Clinical outcomes included Kujala score, Lysholm score, International Knee Documentation Committee (IKDC) score, redislocation or recurrent instability. We conducted pairwise meta-analysis and network meta-analysis respectively using the frequentist model to compare the clinical outcomes.

Results

There were 10 RCTs and 2 cohort studies with a total of 774 patients included in our study. In network meta-analysis, double-bundle medial patellofemoral ligament reconstruction (DB-MPFLR) achieved good results on functional scores. According to the surface under the cumulative ranking (SUCRA), DB-MPFLR had the highest probabilities of their protective effects on outcomes of Kujala score (SUCRA 96.5 %), IKDC score (SUCRA 100.0%) and redislocation (SUCRA 67.8%). However, DB-MPFLR (SUCRA 84.6%) comes second to SB-MPFLR (SUCRA 90.4%) in Lyshlom score. It is (SUCRA 70%) also inferior to vastus medialis plasty (VM-plasty) (SUCRA 81.9%) in preventing Recurrent instability. The results of subgroup analysis were similar.

Conclusion

Our study demonstrated that MPFLR showed better functional scores than other surgical options.

Lateral Patellar Instability

➤

Patellar instability represents a common problem with an evolving understanding and multifactorial pathoetiology. Treatment plans should be based on the identification of contributing anatomical factors and tailored to each individual patient.

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Risks for recurrent instability are dependent on several patient-specific factors including patella alta, increased tibial tubercle-to-trochlear groove (TT-TG) distance, trochlear dysplasia, younger skeletal age, and ligamentous laxity.

➤

Cartilage or osteochondral lesions and/or fractures are commonly observed in first-time patellar dislocation, and magnetic resonance imaging (MRI) should be strongly considered. Advanced imaging modalities, such as computed tomography (CT) or MRI, should also be obtained preoperatively to identify predisposing factors and guide surgical treatment.

➤

Medial patellofemoral ligament (MPFL) reconstruction with anatomical femoral tunnel positioning is associated with lower recurrence rates compared with MPFL repair and has become a common and successful reconstructive surgical option in cases of instability.

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Lateral retinacular tightness can be addressed with lateral retinacular release or lengthening, but these procedures should not be performed in isolation.

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Tibial tubercle osteotomy is a powerful reconstructive tool in the setting of underlying skeletal risk factors for instability and can be of particular benefit in the presence of increased TT-TG distance (>20 mm), and/or in the setting of patella alta.

➤

The indications for trochleoplasty are still developing along with the clinical evidence, but trochleoplasty may be indicated in some cases of severe trochlear dysplasia. Several surgical techniques have indications in specific clinical scenarios and populations, and indications, risks, and benefits to each are progressing with our understanding.

➤

Combined femoral derotational osteotomy and MPFL reconstruction can be considered for patients with a femoral anteversion angle of >30° to improve patient outcomes and reduce recurrence rates.

Double-Tunnel Technique Was Similar to Single-Tunnel Technique in Clinical, Imaging and Functional Outcomes for Medial Patellofemoral Ligament Reconstruction: A Randomized Clinical Trial

PURPOSE

This study aimed to compare the clinical, functional, and imaging outcomes of single-tunnel (ST) and double-tunnel (DT) techniques for medial patellofemoral ligament (MPFL) reconstruction.

METHODS

Ninety-four patients with recurrent patellar instability were randomly divided into 2 groups, receiving either ST or DT MPFL reconstruction. Lateral reticulum release (LRR) and tibial tuberosity (TT) transfer were performed as combined procedures when necessary. Preoperative and postoperative clinical characteristics (symptoms and episodes of redislocation), functional outcomes (Kujala, Lysholm, Tegner, IKDC, and KOOS score), and radiological measurements (congruence angle, patellar tilt angle, lateral patellar angle, and lateral patellar translation) were analyzed.

RESULTS

The analysis included data from 90 patients with 48 patients in the ST group and 42 patients in the DT group. Patients were followed up for a mean period of 37.8 (range: 27-50) months in the ST group and 38.6 (range: 25-53) months in the DT group. Forty-three patients in the ST group and 40 patients in the DT group received combined TT transfer, and all patients underwent LRR. At the latest follow-up, 1 patient in ST group experienced redislocation, while no patient in the DT group sustained clinical failure (P = .347). Imaging measurements decreased significantly to the normal range postoperatively. No significant difference was noted between the postoperative radiological results of the 2 groups. All clinical scores significantly improved postoperatively, and no significant difference was observed between the 2 groups except for the higher Lysholm score (P = .031), KOOS symptoms score (P = .021) and KOOS knee-related quality of life score (P = .043) in the DT group.

CONCLUSION

Both techniques could equally mitigate the patellar lateral translation or redislocation. Our results demonstrate several significant differences in functional outcomes that favored DT MPFL reconstruction but no difference in clinical failure rates and radiological results between ST and DT MPFL reconstruction.

LEVEL OF EVIDENCE

Level I, randomized clinical trial.

Management of Patellar Instability: A Network Meta-analysis of Randomized Control Trials

BACKGROUND

Multiple surgical options exist for the treatment of patellar instability; however, the most common procedures involve either a reconstruction of the medial patellofemoral ligament (MPFL) or a repair/plication of the MPFL and medial soft tissues.

PURPOSE

To perform a network meta-analysis of the randomized controlled trials (RCTs) in the literature to compare MPFL reconstruction, MPFL repair, and nonoperative management for patellar instability.

STUDY DESIGN

Systematic review and network meta-analysis; Level of evidence, 1.

METHODS

The literature search was performed based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. RCTs comparing MPFL reconstruction, MPFL repair, and nonoperative management for patellar instability were included. Clinical outcomes included recurrent instability (including both dislocations and subluxations), redislocation, and Kujala score. Clinical outcomes were compared using a frequentist approach to network meta-analysis, with statistical analysis performed using the statistical software R. The treatment options were ranked using P scores.

RESULTS

There were 13 RCTs with a total of 789 patients, all with a minimum follow-up of 24 months. There were 150 patients treated using MPFL reconstruction, 353 treated using MPFL repair, and 286 treated nonoperatively. Overall, MPFL reconstruction had the highest P score (0.9967) and resulted in a significantly lower recurrence rate than did MPFL repair (odds ratio [OR], 0.42; 95% CI, 0.07-0.72) and nonoperative management (OR, 0.09; 95% CI, 0.03-0.32). In addition, MPFL repair resulted in a significantly lower recurrence rate than did nonoperative management (OR, 0.42; 95% CI, 0.25-0.70). MPFL reconstruction had the highest P score (0.9651) and resulted in a significantly higher Kujala score than did nonoperative management (mean difference, 10.45; 95% CI, 0.41-20.49) but not MPFL repair (mean difference, 0.15; 95% CI, 0.03-0.68). Subgroup analysis revealed that MPFL reconstruction had the highest P score for all outcomes in those with first-time dislocation.

CONCLUSION

The current study demonstrated that MPFL reconstruction results in the lowest rate of recurrent patellar instability and best functional outcomes as measured using the Kujala score.

Preoperative serum calcium could be a prognostic factor for surgical treatment of recurrent patellar dislocation: a retrospective study

Background

Surgical treatment for recurrent patellar dislocation (RPD) could yield good outcomes. While, unsatisfactory recovery still exists in some cases. For all prognostic factors, serum biomarkers have rarely been investigated. This study aimed to evaluate the prognostic value of preoperative serum calcium level, a widely used serum biomarker, in surgical treatment for RPD.

Study design

Retrospective study.

Methods

Ninety-nine patients with RPD were enrolled in the study. Preoperative serum calcium was acquired from routinely tested blood 1 day prior to operation. Demographic data, characteristics of RPD, postoperative functional outcomes were obtained. The association between preoperative calcium and postoperative functional outcomes (Kujala, Lysholm, Tegner, IKDC and KOOS score) was determined by correlation analysis and multivariate linear regression analysis. Poor recovery was determined as Kujala score below 80. The receiver operating characteristic (ROC) curve was used to assess the prognostic value of preoperative calcium.

Results

Patients were followed up for a mean period of 2.45 ± 1.33 years. All clinical scores showed significant improvement at the latest follow-up. Correlation and multivariate linear analyses indicated that serum calcium level was an important factor related with the prognosis of surgical treatment for RPD. According to the ROC curve, the cut-off value for preoperative calcium was 2.225 mmol/L. The clinical outcomes of patients with a preoperative blood calcium < 2.225 mmol/L was significantly worse than that with a higher calcium level. The correspondent sensitivity was 0.812 with a specificity of 0.633.

Conclusion

Operative treatment for RPD achieved good results, while in some cases the functional scores remain inferior. As a serum biomarker, preoperative calcium could be prognostic for outcomes after surgical treatment for RPD.

Protocols of rehabilitation and return to sport, and clinical outcomes after medial patellofemoral ligament reconstruction with and without tibial tuberosity osteotomy: a systematic review

PURPOSE

No consensus exists on rehabilitation programmes after medial patellofemoral ligament reconstruction (MPFLR) with or without tibial tuberosity osteotomy (TTO). This systematic review examined the content and timeline of rehabilitation (weightbearing, range of motion [ROM] and exercise therapy) and return to sport (RTS), as well as patient-reported outcomes after MPFLR with or without TTO.

METHODS

The PubMed, Cochrane Library, Web of Sciences, CINAHL and SPORTDiscus databases were searched from inception to December 2021. Studies that reported postoperative rehabilitation programmes and patient-reported outcomes for patients aged ≥ 18 years who underwent MPFLR with or without concomitant TTO were included.

RESULTS

Eighty-five studies were included, 57 of which were case series and only one randomised controlled trial on rehabilitation programmes. Non-weightbearing was set within one week post-operatively in approximately 80% of weightbearing programmes for MPFLR without and with TTO. Joint immobilisation was set within one week post-operatively in 65.3% and 93.8% of programmes for MPFLR without and with TTO, respectively. Weightbearing and ROM (≤ 90°) restriction were within three weeks post-operatively for > 50% of the programmes. Quadriceps strengthening was the most cited exercise therapy (33 programmes), most often initiated within two weeks post-operatively. However, few other exercise programmes were cited (only nine programmes). RTS was mostly noted at six months post-operatively (35 programmes). The weighted mean Kujala score was 87.4 points.

CONCLUSION

Regardless of TTO addition to MPFLR, most studies restricted weightbearing and ROM only in the early post-operative period, with seemingly favourable clinical results. Limited information was available on post-operative exercise therapy.

Tape Augmentation Does Not Affect Mid-Term Outcomes of Medial Patellofemoral Ligament Reconstruction in Skeletally Mature Adolescent Patients

Purpose

To evaluate mid-term outcomes after medial patellofemoral ligament (MPFL) reconstruction with and without tape augmentation in the skeletally mature adolescent population.

Methods

All patients under age 18 with recurrent patellar instability treated with surgery at a single institution by a single surgeon from January 2013 through June 2017 were identified by current procedural terminology codes. Inclusion criteria were (1) primary MPFL reconstruction, (2) minimum 3 years’ follow-up, (3) skeletal maturity. Exclusion criteria were (1) bilateral MPFL reconstruction using different techniques on each knee, (2) prior surgery for patellar instability. Chart and imaging review was completed. Patients were contacted to complete a questionnaire, which included the International Knee Documentation Committee (IKDC) form.

Results

Fifty-one of 92 eligible patients completed questionnaires. Two patients were excluded. Twenty patients underwent 23 non-augmented MPFL reconstructions; 29 patients underwent 33 augmented MPFL reconstructions. Group demographics were similar. At 4.9 ± 1.2 years follow-up, mean IKDC scores were 77.4 and 79.4 in the nonaugmentation and augmentation groups, respectively. Significantly fewer patients in the augmentation group experienced further injury to their ipsilateral knee compared to the non-augmentation group (6% vs 30%, P = .019). Fewer knees in the augmentation group developed recurrent subjective instability or dislocation after initial surgery requiring surgical correction compared to knees in the nonaugmentation group, although this difference was not significant (6% vs 17%, P = 0.181). Overall patient-reported outcomes were similar between the 2 groups.

Conclusions

There were no significant differences in patient-reported outcomes after MPFL reconstruction with or without tape augmentation. Tape augmentation significantly decreased the risk of subsequent ipsilateral knee injuries, although it did not show a significant difference in recurrent dislocations.

Level of Evidence

IV, therapeutic case series.

Low to moderate risk of nerve damage during peroneus longus tendon autograft harvest

PURPOSE

This study aims to evaluate the proximity of the tendon stripper to both the peroneal and sural nerves during peroneus longus tendon (PLT) autograft harvesting.

METHODS

Ten fresh-frozen human cadaveric lower extremities were used to harvest a full-thickness PLT autograft using a standard closed blunt-ended tendon stripper. The distance to the sural nerve from the PLT (at 0, 1, 2 and 3 cm proximal to lateral malleolus (LM), and the distance to the peroneal nerve and its branches from the end of the tendon stripper were measured by two separate observers using ImageJ software.

RESULTS

The average distance from the PLT to the sural nerve increased significantly from 0 to 2 cm proximal to LM. The average distance to the sural nerve at the LM was 4.9 ± 1.5 mm and increased to 10.8 ± 2.4 mm (2 cm proximal to LM). The average distance from the tendon stripper to the deep peroneal nerve was 52.9 ± 11.4 mm. The average distance to the PLT branch of peroneal nerve was 29.3 ± 4.2 mm. The superficial peroneal nerve, which coursed parallel and deep to the tendon stripper, was on average 5.2 ± 0.7 mm from the end of the stripper. No transection injuries of the nerves were observed in any of the ten legs after harvesting.

CONCLUSION

This cadaver study found during a full-thickness PLT harvest, the distances between the tendon stripper and the nerves were greater than 5 mm with an initial incision at 2 cm proximal to LM which is recommended.

Medial Patellofemoral Ligament Repair or Medial Advancement: Is There a Role?

Patellar instability is one of the most prevalent knee disorders, with dislocations occurring in 5 to 43 cases per 10,000 annually. Traumatic patellar dislocation can result in significant morbidity and is associated with patellofemoral chondral injuries and fractures, medial soft tissue disruption, pain, and reduced function, and can lead to patellofemoral osteoarthritis. Chronic and recurrent instability can lead to deformation and incompetence of the medial soft tissue stabilizers. Despite recent gains in understanding the pathoanatomy of this disorder, the management of patients with this condition is complex and remains enigmatic.

Wide Patellar Insertion Medial Patellofemoral Ligament Reconstruction with Internal Bracing

Medial patellofemoral ligament (MPFL) reconstruction is a common procedure to address MPFL deficiency. Various techniques have been reported, with the best method still being pursued. Previous studies have revealed the advantage of internal bracing and possible advantage of wide patellar insertion in MPFL reconstruction. Thus, we would like to introduce a technique that combines the internal bracing and wide patellar insertion in MPFL reconstruction, in which the critical points are proper location of the patellar and femoral tunnels and proper tensioning of the augmenting sutures and the whole graft complex. Our clinical experience indicates that the proper application of this technique can lead to satisfactory clinical outcome. We consider the introduction of this technique will provide more insight to MPFL reconstruction.

Effects of Lateral Patellar Retinaculum Release for Recurrent Patella Dislocation: A Prospective Study

Purpose

Recurrent patellar dislocation (RPD) is the most common complication of patellar instability and the medial patellofemoral ligament (MPFL) reconstruction has become its reference treatment. Lateral patellar retinaculum (LPR) release used to be performed in association with MPFL reconstruction. The aim of this study was to investigate the added values of MPFL reconstruction plus LPR release for RPD.

Methods

After Institutional Review Board approval, RPD patients from October 2014 to April 2019 were randomly assigned into two groups (isolated MPFL reconstruction [Group I] and MPFL reconstruction plus LPR release [Group II]) and prospectively assessed until 12 months after surgery. Knee joints with flexion of 20° were scanned by a 64-row CT scanner. Congruence angle (CA), patella tilt angle (PTA), lateral patellofemoral angle (LPFA), tibial tuberosity-trochlear groove distance and patellar tilt with the quadriceps relaxed and contracted were measured. Knee function was assessed by Lysholm knee score and International Knee Documentation Committee (IKDC) score. Patients were followed up for at least 12 months.

Results

A total of 87 RPD patients (45 for Group I and 42 for Group II) were selected in this study. Preoperative clinical characteristics were not significantly different across groups. No serious complications were noted in either group. It was statistically insignificant between the two group patients in terms of postoperative patella associated measurements (P > 0.05 for all). The Lysholm score and IKDC score of Group I (84.5 ± 7.1 and 87.9 ± 7.2) were significantly less than that of Group II (89.7 ± 8.7 and 93.1 ± 7.7), which indicated the better knee function of Group II.

Conclusion

LPR release plus MPFL reconstruction provides additional benefits compared with isolated MPFL reconstruction in knee function. A combination of surgical treatments for RPD should be recommended.

Anatomic medial patellofemoral ligament (MPFL) reconstruction with and without tibial tuberosity osteotomy for objective patellar instability

PURPOSE

The aim of this study was to evaluate the clinical outcomes of patients treated with anatomic medial patellofemoral ligament (MPFL) reconstruction with and without tibial tuberosity osteotomy (TTO). Correlations between patient's age, gender, pre-injury physical activity and the achieved results were investigated as secondary endpoints.

METHODS

An observational retrospective study with prospective collected data was performed. Inclusion criteria were: treatment with anatomic MPFL reconstruction with gracilis tendon according to Schӧttle's technique performed between 2011 and 2017; associated TTO as unique accessory procedure; skeletal joint maturity; a minimum follow-up of 12 months after surgery. Clinical outcomes were assessed with the Kujala, Lysholm and Tegner scores.

RESULTS

Forty patients (42 knees) were included, 64% of them underwent TTO. The Kujala score significantly improved from 47.4 ± 17.6 preoperatively to 89.4 ± 13.6 postoperatively (p < 0.01). The average Lysholm score was 45.6 ± 20.5 preoperatively: it showed a significant increase to 89.8 ± 12.8 postoperatively (p < 0.01). Pre-injury mean Tegner was 5.9 ± 1.8, while it dropped to 3.0 ± 1.6 after injury. After surgery, Tegner resulted 4.9 ± 1.6. Forty-three percent of patients regained the pre-injury sport activity level. Redislocation rate was 2.4%.

CONCLUSION

Anatomic MPFL reconstruction allows excellent patellar stability recovery, knee functionality improvement, return to Activities of Daily Living and a low redislocation rate. Better results were achieved in younger (under 30 years old) and higher sports activity-level subjects. The TTO association provided clinical results comparable to isolated MPFL reconstructions, suggesting that the two procedures can be safely accomplished together without affecting the positive outcomes.

LEVEL OF EVIDENCE

Level IV.

Single-tunnel and double-tunnel medial patellofemoral ligament reconstructions have similar clinical, radiological and functional results

PURPOSE

The aim of the present study was to evaluate the clinical, radiological and functional results of patients underwent single-tunnel (ST) and double-tunnel (DT) medial patellofemoral ligament(MPFL) reconstructions with hamstring autograft following recurrent patella dislocation prospectively in a single institution.

METHODS

From 2013 to 2017, 80 patients with symptomatic recurrent patellar dislocation or instability were randomly divided into 2 groups for MPFL reconstruction with ST technique or DT technique and evaluated prospectively. In the ST group, there were 20 male and 20 female with a median follow-up of 46.5 months (range 24-74). The median age was 15 years (range 10-28). In the DT group, there were 18 male and 22 female with a median follow-up of 40 months (range 24-74). The median age was 19 years (range 14-29). Clinical scores (Kujala score, Lysholm score, Tegner score and IKDC score) and radiological measurements (congruence angle and patellar tilt angle) of the patients were evaluated preoperatively and at postoperative 24th month. Isokinetic dynamometric tests were performed at postoperative 24th month and the difference between the operated leg and the non-operated leg was found as a percentage deficit.

RESULTS

There were no postoperative complications, redislocation or subluxation in any patient. Kujala, Lysholm, Tegner and IKDC scores were better and statistically significant postoperatively in both groups (p < 0.05). However, there was no statistically significant difference between the groups (n.s.). The congruence angle and patellar tilt angle were found to be returned to normal values postoperatively, but there was no statistically significant difference between the groups (n.s.). There was no statistically significant difference between the two groups in isokinetic dynamometric tests performed as 60° flexion, 60° extension, 180° flexion and 180° extension (n.s.).

CONCLUSION

The present study is the first that compared the clinical, radiological and functional results of the ST and DT techniques to date. Regardless of the number of the tunnels, similar results were obtained in ST and DT reconstruction using transpatellar tunnel technique.

LEVEL OF EVIDENCE

Level I.

Evaluation of the 'Spaarne soft tissue procedure' as a treatment for recurrent patellar dislocations: a four-in-one technique

PURPOSE

The 'Spaarne soft tissue procedure', is a 4-in-1 soft tissue procedure that treats recurrent patellar dislocations in the young and active population. The procedure has not yet described elsewhere. The purpose of this study is to analyse the redislocation rate and to evaluate the postoperative knee function and patient satisfaction.

METHODS

Twenty-seven patients (34 knees) underwent the four-in-one SST-procedure. The 4-step technique required a minor change in 2010, including the use of a smaller strip of the patellar tendon for transposition. After a median follow-up of 10.4 years, the redislocation rate was evaluated as the primary outcome measure. Secondary outcome measures were functional outcome (IKDC, Kujala, Lysholm and Tegner activity scale) and Numeric Rating Scales for satisfaction and pain.

RESULTS

Redislocation occurred in 8 cases (23.5%) and subluxation occurred in 13 cases (38.2%) post-surgery. A significant higher number of redislocations and subluxations were seen before 2010 (p = 0.04, p = 0.03). The median postoperative IKDC, Lysholm and Kujala scores for the total group were 54, 76 and 81 respectively. Pre- and postoperative Tegner activity scale were both level 3. Median NRS scores during rest, walking and sports were 1, 3 and 5 respectively. Satisfaction with the procedure was reported as 'excellent' or 'good' by 79% of the patients.

CONCLUSION

Despite the high overall redislocation rate and increased pain scores, the SST-procedure shows to be a safe procedure in patients with recurrent patellar dislocations based on the cases after 2010. Mid- and long-term results show moderate to good functional outcomes and satisfaction.

LEVEL OF EVIDENCE

Therapeutic retrospective cohort study, LEVEL III.

A method for calculating the fragility index of continuous outcomes

OBJECTIVE

Clinicians' overdependence on p-values to determine significance in clinical trials is common yet potentially misleading. The Fragility Index (FI) describes how robust a significant result is by determining the number of events the statistical significance hinges on. However, this concept cannot be applied to nondichotomous variables. We describe a method to calculate a Continuous Fragility Index (CFI) for continuous variables. We further provide a method to estimate CFI when original data is not available.

STUDY DESIGN AND SETTING

An iterative substitution algorithm is described to calculate CFI prospectively from data or retrospectively from summary statistics and its response to variations in the data is reported. We then apply this method to a previously published review as a proof-of-concept.

RESULTS

The CFI increases linearly with sample size, logarithmically with mean difference, and decreases exponentially with standard deviation. Forty-eight studies were included of which 30 had significant non-dichotomous outcomes. CFI and FI were uncorrelated and mean CFI was significantly higher than FI (9 vs. 2, P< 0.001).

CONCLUSION

Our algorithm extends fragility to continuous outcomes, expanding the applications of the fragility concept. The fragility of outcomes within a single study may vary based on variable type and should be evaluated independently.

Mid-Term Outcomes of Combined Hip Arthroscopy and Limited Open Capsular Plication in the Non-Dysplastic Hip

BACKGROUND

Hip microinstability remains poorly-defined but increasingly diagnosed in the setting of borderline dysplasia (LCEA 20-25°), soft tissue laxity, or following unrepaired arthroscopic capsulotomy. While hip microinstability is com-monly treated with arthroscopic capsular plication with short-term outcomes reported, this procedure has been performed open for some time. The purpose of current study was to assess the durability of outcomes of combined arthroscopy and open capsular plication in treating symptomatic hip microinstability at mid-term follow-up.

METHODS

We retrospectively identified hips that underwent combined hip arthroscopy and open capsular plication for symptomatic microinstability between 2008 and 2013. Hips with excessive femoral anteversion (femoral version >35°) or classic acetabular dysplasia (LCEA <20°) were treated with bony reorientation and were not included in the current study. Patient reported outcomes scores were collected preoperatively and at a minimum five year follow-up. Hips that required reoperation or did not meet criteria for minimally clinically important difference (MCID, ≥8 increase in mHHS) or patient acceptable symptom scores (PASS, mHHS) were considered failures.

RESULTS

A total of 27 hips met criteria for inclusion and follow-up was obtained for 22 hips (81.5%) at a mean of 7.1 years. All patients were female with a mean age of 25.9 years and 7 (32%) hips had previous surgery. Patients undergoing the combined procedure improved from a mean baseline mHHS of 55.3±13 to a mean follow-up mHHS of 74.5±20.9 (p<0.001). At midterm follow-up, 54.5% of hips met criteria for PASS and 68.2% of hips met criteria for MCID, with 72.7% of hips meeting criteria for either MCID or PASS. Overall, 10 hips (45%) were considered failures with 6 hips (27%) requiring reoperation and an additional 4 hips (18%) with clinical failure. Hips without previous surgery had a failure rate of 33.3% (5/15) while 71.4% (5/7) of those with previous surgery failed (P=.09).

CONCLUSION

Our study demonstrates a high (45%) rate of reoperations and persistent symptoms in hips with microinstability treated with combined arthroscopy and open capsular plication. Further mid- and long-term studies evaluating soft tissue plication are needed, as well as comparisons with bony procedures in the setting of microinstability are needed.Level of Evidence: III.

Combined medial patellofemoral and medial patellotibial reconstruction for patellar instability: a PRISMA systematic review

BACKGROUND

The medial patellofemoral ligament (MPFL) works in association with the medial patellotibial ligament (MPTL) and the medial patellomeniscal ligament (MPML) to impart stability to the patellofemoral joint. The anatomy and biomechanical characteristics of the MPFL have been well described but little is known about the MPTL and MPML. Several reconstruction procedures of the MPFL with semitendinosus, gracilis, patellar and quadriceps tendons, allografts and synthetic grafts have been described. No clear superiority of one surgical technique over another is evident.

METHODS

A systematic review of the literature was conducted using PRISMA guidelines. Inclusion criteria were articles that reported clinical outcomes of combined reconstruction of MPTL and MPFL. The methodological quality of the articles was determined using the modified Coleman Methodology Score (CMS).

RESULTS

Nine articles were included, reporting the clinical outcomes of 197 operated knees. The surgical procedures described include hamstrings grafting and transfer of the medial patellar and quadriceps tendons with or without bony procedures to reconstruct the MPTL in association with the MPFL. Overall, good and excellent outcomes were achieved. The median CMS is 70.6 ± 14.4 (range 38 to 84).

CONCLUSION

Different techniques are reported, and outcomes are good with low rates of recurrence. The quality of the articles is variable, ranging from low to high. Appropriately powered randomized controlled trials are needed to better understand what the adequate indications for surgery in patients with patellar instability and clinical outcomes are. Combined reconstruction of MPFL and MPTL leads to favourable clinical outcomes, supporting its role as a valid surgical procedure for patellar stabilization.

Comparative study of three different combination surgical methods for recurrent patella dislocation

PURPOSE

The effects of different combination of surgical techniques for recurrent patella dislocation (RPD) remain unclear. Thus, aim of this study was to investigate the surgical outcomes of different combination of surgical techniques for RPD.

METHODS

The clinical data of 79 patients with RPD from August 2014 to October 2016 were analysed retrospectively. Knee joint was assessed according to measurements of the congruence angle (CA), patellar tilt angle (PTA) and lateral patellofemoral angle (LPFA). Knee function was evaluated by Kujala patellofemoral score, Lysholm knee score and Tegner score. Patients were followed up by out-patient examination and telephone till October 2018.

RESULTS

Preoperative clinical characteristics were similar across groups. It was statistically insignificant among three groups in CA, PTA, LPFA and redislocation rate. In term of knee functions, the MPFL reconstruction and LPR release group had the highest score (Lysholm score: 91.82 ± 4.64, Kujala score: 94.22 ± 4.26, Tegner score: 5.80 ± 1.00, respectively) and the LPR release and MPR plication had the lowest score (Lysholm score: 78.10 ± 6.90, Kujala score: 80.91 ± 4.30, Tegner score: 4.98 ± 1.22, respectively).

CONCLUSION

Three combinations of surgical methods were similar in terms of postoperative joint congruence and redislocation rate, but MPFL reconstruction combined with LPR release is worthy to be promoted with the highest knee function scores.

Editorial Commentary: Repair or Reconstruct? Addressing Medial Patellofemoral Ligament Insufficiency in the Absence of Morphologic Abnormalities

The role of medial patellofemoral ligament (MPFL) repair versus reconstruction in the treatment of patellar instability continues to undergo debate. Repair of the ligament can be technically less demanding with fewer risks of morbidity, whereas reconstruction carries concerns of graft malpositioning or over-tensioning as well as the risk of patellar fracture. Studies directly comparing the 2 procedures in the setting of recurrent patellar instability have consisted of small series or low levels of evidence that inevitably include patients with concurrent morphologic risk factors such as tuberosity malalignment or patella alta, which are known factors that can influence the biomechanical behavior of the MPFL. Heterogeneity in patient-related risk factors and surgical techniques continues to pose limitations in allowing for direct comparisons between procedures. For the treatment of recurrent patellar instability in the setting of no (or concurrently addressed) morphologic abnormalities, MPFL reconstruction has become a common procedure and generally preferred approach. The superior outcomes associated with reconstruction over repair, however, should be qualified with the fact that attention to the critical details of the technique, including graft position and tension, is paramount to success when performing this procedure.

Recurrent Patellar Dislocations Without Untreated Predisposing Factors: Medial Patellofemoral Ligament Reconstruction Versus Other Medial Soft-Tissue Surgical Techniques-A Meta-analysis

PURPOSE

To provide a direct comparison between medial patellofemoral ligament (MPFL) reconstruction and the other medial patellofemoral soft-tissue surgeries in the restoration of the medial patellar restraint after lateral patellar dislocations in the absence of untreated predisposing factors such as high grade trochlear dysplasia, knee malalignment, patella alta or high tibial tubercle-trochlear groove distance.

METHODS

PubMed, Cochrane-library, Web of Science, and gray literature databases were searched to find all the relevant records. Study selection, data extraction, and risk of bias assessment were performed following the Cochrane and Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. Different techniques to treat lateral patellar dislocation in the absence of untreated predisposing factors were compared in terms of redislocation and complication rates, Kujala, Lysholm, International Knee Documentation Committee, and Tegner scores at the short-term (3 years) and long-term (>3 years) follow-up through meta-analyses.

RESULTS

Six studies involving 319 knees were included in the meta-analysis. The analyses of redislocation (0.7% vs 2.9%) and minor complication rates (12% vs 9%) showed no significant differences between MPFL reconstruction and other medial soft-tissue surgeries. Significant differences favoring MPFL reconstruction were documented in Kujala and Lysholm scores at short-term (8.6, P< .001; 10.9, P < .001) and long-term follow-ups (6.3, P = .02; 13.5, P < .001). No significant differences were found in the analyses of International Knee Documentation Committee (P = .10) and Tegner scores (P = .19). Level of evidence was low or very low.

CONCLUSIONS

MPFL reconstruction and medial patellofemoral soft-tissue surgery procedures were both effective in restoring the medial restraining forces preventing redislocation, but MPFL reconstruction provided better functional outcomes both at short-term and long-term follow-up. Thus, besides the treatment of predisposing factors, MPFL reconstruction seems to be, based on the results of this meta-analysis, a suitable strategy to restore the medial restraining function in the treatment of recurrent LPD.

LEVEL OF EVIDENCE

Level III (meta-analysis of randomized and nonrandomized comparative trials).

Surgical treatment is better than non-surgical treatment for primary patellar dislocation: a meta-analysis of randomized controlled trials

BACKGROUND

At present, the best treatment for primary patellar dislocation (PPD) has not been unified. Moreover, meta-analyses comparing the non-surgical and surgical treatments of PPD are lacking. Thus, we aimed to compare the clinical efficacy of surgical or non-surgical treatment of PPD.

METHODS

Randomized controlled studies of surgical and non-surgical treatments of PPD from 1966 to 2018 were retrieved from the following databases: PubMed, EMBASE, Cochrane Library, Wanfang Database, China Knowledge Network, Google Scholar, and Weipu Database. We screened for literature that met the inclusion criteria and extracted useful data for our meta-analysis.

RESULTS

Nine studies, involving 492 patients, met the inclusion criteria and were analyzed in this study. The recurrence rate of patellar dislocation in the surgical group was lower than that in the non-surgical group (P = 0.04]). Subgroup analysis according to the follow-up time showed that the Kujala score (P < 0.001) and lower recurrence rate of dislocation (P = 0.05) than the non-surgical group in the short term. Subgroup analysis according to surgical year showed that the surgical group get higher Kujala score (P < 0.001) and lower recurrence rate of dislocation (P = 0.01) than the non-surgical group in recent years.

CONCLUSION

Surgical treatment can provide better clinical results in a short period of time, and patients may achieve good results within 10 years owing to the advances in surgical techniques and instruments. Thus, we recommend surgical treatment as the preferred treatment for primary patellar dislocation.

The Vastus Medialis Insertion Is More Proximal and Medial in Patients With Patellar Instability: A Magnetic Resonance Imaging Case-Control Study

Background:

The anatomy and function of the quadriceps muscle play a role in patellofemoral stability. Few studies have evaluated anatomic differences in the vastus medialis between patients with and without patellar instability.

Purpose:

To compare the anatomy of the vastus medialis using magnetic resonance imaging in patients with patellar instability to a control group.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A group of patients with patellar instability were sex-matched with a control group with anterior cruciate ligament tears, meniscal injuries, or sprains; patients younger than 15 years were excluded. The anatomy of the vastus medialis was examined by the distance between the distal origin of the vastus medialis in the femur and the medial femoral condyle, the distance from the proximal pole of the patella to the most distal insertion of the muscle and its ratio to the length of the articular surface of the patella, and a qualitative description of the insertion position of the muscle fibers (directly in the patella or the medial retinaculum).

Results:

Both groups comprised 78 knees (48 female; 61.5%). The mean age in the control and patellar instability groups was 30.2 ± 7.8 years and 25.6 ± 7.5 years, respectively (P = .001). The distance from the vastus origin to the condyle was 27.52 ± 3.49 mm and 26.59 ± 3.43 mm, respectively (P = .041); the distance from the proximal pole of the patella to the most distal muscle insertion was 17.59 ± 5.54 mm and 15.02 ± 4.18 mm, respectively (P < .001); and the ratio of this distance to the joint surface was 0.586 ± 0.180 and 0.481 ± 0.130, respectively (P < .001). In 75.6% of knees in the patellar instability group, the insertion of the vastus was into the medial retinaculum and not into the patella compared with 52.6% in the control group (P = .003; odds ratio, 2.8).

Conclusion:

The distal insertion of the vastus medialis differed in knees with patellar instability, with a more proximal insertion and less patellar coverage relative to controls, and was more frequently found in the retinaculum instead of directly in the patella.

Concepts of the Distal Medial Patellar Restraints: Medial Patellotibial Ligament and Medial Patellomeniscal Ligament

The important medial patellar ligamentous restraints to lateral dislocation are the proximal group (the medial quadriceps tendon femoral ligament and the medial patellofemoral ligament) and the distal group [medial patellotibial ligament (MPTL) and medial patellomeniscal ligament (MPML)]. The MPTL patellar insertion is at inferomedial border of patella and tibial insertion is in the anteromedial tibia. The MPML originates in the inferomedial patella, right proximal to the MPTL, inserting in the medial meniscus. On the basis of anatomy and biomechanical studies, the MPTL and MPML are more important in 2 moments during knee range of motion: terminal extension, when it directly counteracts quadriceps contraction. In a systematic review on MPTL reconstructions 19 articles were included detailing the clinical outcomes of 403 knees. All were case series. Overall, good and excellent outcomes were achieved in >75% of cohorts in most studies and redislocations were <10%, with or without the association of the medial patellofemoral ligament. The MPTL is a relevant additional tool to proximal restraint reconstruction in select patient profiles; however, more definitive clinical studies are necessary to better define surgical indications.

Medial patellofemoral ligament reconstruction using an autograft or allograft for patellar dislocation: a systematic review

Purposes

The purpose of this study is to review the use of an allograft or autograft in medial patellofemoral ligament (MPFL) reconstruction.

Materials and methods

Various electronic databases were searched for relevant articles published from January 2000 to September 2017 that evaluated clinical outcomes of MPFL reconstruction using an autograft or allograft. Data search, extraction, analysis, and quality assessments were performed based on Cochrane Collaboration guidelines.

Results

The study of 21 autografts and one allograft was included in this review. Although direct comparative studies were unavailable, the Kujala score and subjective results were reported in the majority of these studies. While the use of an autograft for MPFL reconstruction yielded satisfactory clinical outcomes with few perioperative complications, no new outcome has been drawn from the use of allografts.

Conclusions

Although many studies have shown favorable clinical results for MPFL reconstruction using an autograft, the clinical results of MPFL reconstruction using an allograft have not yet been sufficient to achieve meaningful clinical results due to low levels of evidence. Direct comparisons were not conducted because there were very few studies on allografts; thus, further research in this area should be performed in the future.

Electronic supplementary material

The online version of this article (10.1186/s43019-019-0008-0) contains supplementary material, which is available to authorized users.

Good Outcomes of Combined Femoral Derotation Osteotomy and Medial Retinaculum Plasty in Patients with Recurrent Patellar Dislocation

Objectives

To report the clinical outcomes of combined femoral derotation osteotomy and medial retinaculum plasty for recurrent patellar dislocation in patients with excessive femoral anteversion.

Methods

From January 2015 to March 2018, 20 knees in 20 patients (18 female, 2 male) with a mean age of 21 ± 4.2 years (range, 16 to 28 years) were retrospectively reviewed. All patients had undergone femoral derotation osteotomy and medial retinaculum plasty for recurrent patellar dislocation and excessive femoral anteversion angle (FAA > 25°). CT and X‐rays were used to assess the correction of the femoral anteversion angle, the tibia tuberosity‐trochlear groove (TT‐TG) distance, patellar tilt, and the congruence angle following the combinatory operations. Subjective scores, such as Kujala, International Knee Documentation Committee (IKDC), Tegner, and visual analogue scale (VAS) scores, were used to evaluate knee function preoperatively and postoperatively.

Results

No recurrence of patellar dislocation occurred in these patients during an average of 18 months (range, 12 to 23 months) of follow‐up. The mean of the FAA was corrected to 15.80° ± 3.58° postoperatively compared with 31.42° ± 4.95° preoperatively (P < 0.001). The TT‐TG distance was decreased from 22.17 ± 5.28 mm before surgery to 19.42 ± 4.57 mm after surgery (P = 0.03). The patellar tilt and congruence angle were improved from 30.43° ± 5.30°, 43.30° ± 11.04° to 15.80° ± 3.94°, 16.64° ± 9.98°, respectively (P < 0.001). The Kujala score was improved from 72.4 ± 19.90 before the surgery to 88.2 ± 12.25 after the surgery (P < 0.001). The IKDC score was improved from 70.56 ± 21.44 to 90.78 ± 14.32, and the VAS score was decreased from 4.23 ± 2.11 preoperatively to 1.27 ± 1.08 postoperatively (P < 0.001). No significant difference in Tegner score (5.46 ± 2.49 vs 5.79 ± 1.44) was found before and after the surgery (P = 0.2). Patients younger than 20 years old had lower Kujala (83.46 ± 14.56 vs. 90.84 ± 7.74, P = 0.02) and IKDC (83.49 ± 17.35 vs 92.46 ± 9.28, P = 0.04) scores than those older than 20 years.

Conclusion

Good knee function, pain relief, and improved patellofemoral congruence were achieved with the combined femoral derotation osteotomy and medial retinaculum plasty. The combined operations serve as an ideal treatment for recurrent patellar dislocation and address the primary risk factors.

Medial Patellofemoral Ligament Reconstruction: A Comparison of Single-Bundle Transpatellar Tunnel and Double-Anchor Anatomic Techniques for the Treatment of Recurrent Lateral Patellar Dislocation in Adults

PURPOSE

To compare the stability and clinical outcomes of 2 medial patellofemoral ligament reconstruction (MPFLR) techniques for the treatment of recurrent lateral patellar dislocation in adults.

METHODS

Ninety-one patients with recurrent patellar dislocation were randomly divided into 2 groups, undergoing either the traditional single-bundle transpatellar tunnel technique (group A) or the double-anchor anatomic reconstruction technique (group B). Preoperatively and at follow-up, the patellar position and rotation were evaluated by computed tomography with the congruence angle, lateral patellar angle, patellar tilt angle, and lateral patellar translation; the subjective symptoms and functional outcomes were evaluated with Kujala, Lysholm, Tegner, and International Knee Documentation Committee subjective scores. Clinical examinations were also performed, and redislocations or episodes of instability were recorded.

RESULTS

Patients were followed up for a mean period of 41.11 ± 7.40 months (range, 29-62 months). At the final point, no recurrent patellar dislocations occurred, except in 4 patients with instability symptoms in group A; however, no significant difference between the 2 groups was seen (χ² = 2.503, P = .114). The measurement results from computed tomography decreased significantly to the normal range, and no significant difference was found between the 2 groups except for the lesser patellar tilt angle in group B (t = 2.175, P = .030). The clinical examination improved significantly, no patient exhibited a positive apprehension test in either group, and the number of patients with abnormal lateral patellar translation grade and firm end point showed no statistically significant differences between the 2 groups (P > .05). All score systems significantly improved with no significant difference between the 2 groups except for the higher Kujala score (t = -40.635, P = .001) and International Knee Documentation Committee score (t = -33.823, P = .003) in group B.

CONCLUSIONS

Both MPFLR techniques achieved good results in the treatment of patellar dislocation. Compared with the single-bundle transpatellar tunnel technique, the double-anchor anatomic MPFLR technique may be more effective with a more congruous patellofemoral joint and better knee function.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Anteromedial Tibial Tubercle Osteotomy Improves Results of Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Instability in Patients With Tibial Tuberosity-Trochlear Groove Distance of 17 to 20 mm

PURPOSE

To compare the midterm clinical outcomes of anteromedialization tibial tubercle osteotomy combined with medial patellofemoral ligament reconstruction (TTO+MPFLR) with MPFLR alone (MPFLRa) for the treatment of recurrent patellar instability (RPI) in patients with a tibial tuberosity-trochlear groove (TT-TG) of 17 to 20 mm.

METHODS

From January 2008 to August 2013, patients with RPI and a TT-TG of 17 to 20 mm were divided into 2 groups: TTO+MPFLR or MPFLRa. Subjects were evaluated for J sign classification (1-4+); patellar glide (1-4+); the apprehension test; increased femoral anteversion; the Caton index; trochlear dysplasia; TT-TG; and Kujala, Lysholm, International Knee Documentation Committee (IKDC), and Tegner scores. Kujala improvement was the primary outcome.

RESULTS

Forty-two subjects were evaluated, 18 in the TTO+MPFLR group and 24 in the MPFLRa group. Mean follow-up time was 40.86 months (range, 24-60 months). Demographics between the groups were not different. Preoperatively, there was no statistically significant difference between groups regarding J sign classification; patellar glide; the apprehension test; increased femoral anteversion; the Caton index; trochlear dysplasia; TT-TG; and Kujala, Lysholm, IKDC, and Tegner scores. Postoperative J sign classification mean results comparing TTO+MPFLR and MPFLRa, respectively, were 1 and 1.33 (P = .006). Improvement was significantly higher in the TTO+MPFLR group in all scores except for Tegner. Kujala improvement, 30.27 and 23.95, respectively (P = .003), was also clinically significant, favoring TTO+MPFLR. Lysholm improvement was 40.5 and 36.2, respectively (P = .02), and IKDC improvement was 38.59 and 31.6, respectively (P = .002). There were no reported recurrent subluxations or dislocations in either group.

CONCLUSIONS

TTO+MPFLR resulted in better functional outcome scores and patellar kinematics compared with MPFLRa in the surgical treatment of RPI in patients with a TT-TG distance of 17 to 20 mm.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Sporting activity is reduced following medial reefing performed for patellar dislocation : A retrospective case series of 144 patients with a minimum follow-up of 24 months

Background

Patellar dislocation is common in young and active patients. The purpose of this study was to determine sporting activity following the medial reefing of patellar dislocation.

Methods

One hundred forty-four patients with objective patellar dislocation were treated between 2004 and 2013. Three groups were analyzed retrospectively with a minimum follow-up of 24 months: (1) primary dislocation that was treated with medial reefing without a recurrent dislocation until the day of follow-up (n = 74), (2) primary dislocation that was initially treated with medial reefing but with a recurrent dislocation until the day of follow-up (n = 44), and (3) medial reefing after failed conservative treatment (n = 26). Sporting activity was assessed using a widely-used sporting activity questionnaire and the Tegner score prior to the injury and at the follow-up (58.7 ± 22.6 months after the injury). Clinical outcomes were assessed using IKDC and Kujala score.

Results

The Kujala score was 94.7 ± 9.3 for Group 1, 84.1 ± 16.6 for Group 2 and 93.4 ± 9.7 for Group 3. IKDC at the time of follow-up was 97.2 ± 9.3 for Group 1, 86.1 ± 14.6 for Group 2 and 95.1 ± 11.1 for Group 3. 91.9% of Group 1 and 92.3% of Group 3 were active in sports prior to their injuries and at the time of the follow-up. In Group 2, sporting activity reduced from 81.8 to 75.0%. In all groups, a shift from high performance to recreational sports was found.

Conclusions

Despite good clinical results, sporting activity was reduced following patellar dislocation treated with medial reefing. Also, a shift from engagement in high- to low-impact sports among the participants was noted.

Combined Reconstruction of the Medial Patellofemoral Ligament (MPFL) and Medial Quadriceps Tendon-Femoral Ligament (MQTFL) for Patellar Instability in Children and Adolescents: Surgical Technique and Outcomes

OBJECTIVES

A variety of surgical options exist to treat the challenging problem of recurrent patellar instability in children and adolescents. The goal of the current study is to describe a novel combined reconstruction technique of both the medial patellofemoral ligament (MPFL) and the medial quadriceps tendon-femoral ligament (MQTFL) and report patient outcomes of a single-surgeon series.

METHODS

All patients studied underwent simultaneous MPFL and MQTFL reconstruction for patellar instability using gracilis allograft. Demographic, clinical, and radiographic data were collected. Subjective outcomes were assessed for a minimum of 1 year postoperatively.

RESULTS

Twenty-five patients (27 knees), including 15 female and 10 male individuals with an average age of 15.0±2.2 years (range, 10.3 to 18.9), were included. Prior ipsilateral patellofemoral surgery had been performed in 6 of 25 (24%) patients. Simultaneous hemiepiphysiodesis for valgus deformity at the time of combined reconstruction was performed in 5 of 25 (20%) patients. Preoperative imaging showed a mean tibial tubercle-trochlear groove of 17.2±3.8, Caton-Deschamps Index (CDI) of 1.13±0.16, and trochlear dysplasia Dejour A/B [22/26 (85%)] or Dejour C/D [4/26 (15%)]. A total of 18 patients (19 knees, 72%) returned outcomes questionnaires at a mean 2.0±0.5 years after surgery. Mean Kujala, Pedi-IKDC, and Lysholm scores were 85.9±13.9, 81.5±15.2, and 84.3±13.5, respectively. Later revision procedure (tibial tubercle osteotomy) for recurrent patellar instability was required in 2 of 25 patients (8%) patients, and another patient reported persistent instability not requiring revision. Return to sports was possible in 10 of 13 self-reported athletes (77%) at a mean of 5.8±3.9 months (range, 2 to 15).

CONCLUSIONS

The present study describes a combined MPFL-MQTFL reconstruction technique with favorable short-term results. Although particularly useful in the skeletally immature patient where tibial tubercle osteotomy should be avoided and patellar fixation minimized, combined reconstruction may potentially be appropriate for older patients with patellofemoral instability as well. This technique more closely recreates the native anatomy of both the MPFL and MQTFL, may decrease the risk of patellar fracture, and can be useful in the revision setting.

LEVEL OF EVIDENCE

Level IV.

Which Technique Is Better for Treating Patellar Dislocation? A Systematic Review and Meta-analysis

PURPOSE

To clarify the discrepancy in surgical options and present evidence to treat patellar dislocation by evaluating which of the techniques yields better improvement in stability and functional recovery for patellar dislocation.

METHODS

The MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus electronic databases were searched for relevant articles comparing the outcomes of medial patellofemoral ligament (MPFL) treatment published up until August 2017. Data searching, extraction, analysis, and quality assessment were performed based on The Cochrane Collaboration guidelines. Clinical outcomes were evaluated using various outcome values in various techniques. For results with high heterogeneity, 95% prediction intervals (PIs) were also investigated.

RESULTS

Eleven clinical studies were investigated. In patients with primary patellar dislocation, there were no significant differences in all evaluated outcomes between the conservative and surgical treatment groups. For patients with recurrent patellar dislocation, MPFL reconstruction was associated with a favorable Kujala score (mean difference, -8.91; 95% confidence interval, -14.05 to -3.77; I² = 94%; 95% PI, -9.64 to -8.1) and Lysholm score (mean difference, -13.51; 95% confidence interval, -21.35 to -5.68; I² = 96%; 95% PI, -14.86 to -12.16) when compared with soft tissue realignment surgery.

CONCLUSIONS

Although surgical treatment of the MPFL for primary patellar dislocation is not superior to conservative treatment in restoring knee function and clinical outcomes, MPFL reconstruction is associated with more favorable clinical outcomes compared with medial soft tissue realignment surgery in patients with recurrent patellar dislocation. Double-bundle MPFL reconstruction seems to provide more favorable outcomes than single-bundle MPFL reconstruction, but this finding should be interpreted with caution because the evidence levels were low and were from only a few studies.

LEVEL OF EVIDENCE

Level III, meta-analysis.

Allowing one quadrant of patellar lateral translation during medial patellofemoral ligament reconstruction successfully limits maltracking without overconstraining the patella

PURPOSE

Graft tensioning during medial patellofemoral ligament (MPFL) reconstruction typically allows for lateral patellar translation within the trochlear groove. Computational simulation was performed to relate the allowed patellar translation to patellofemoral kinematics and contact pressures.

METHODS

Multibody dynamic simulation models were developed to represent nine knees with patellar instability. Dual limb squatting was simulated representing the pre-operative condition and simulated MPFL reconstruction. The graft was tensioned to allow 10, 5, and 0 mm of patellar lateral translation at 30° of knee flexion. The patellofemoral contact pressure distribution was quantified using discrete element analysis.

RESULTS

For the 5 and 10 mm conditions, patellar lateral shift decreased significantly at 0° and 20°. The 0 mm condition significantly decreased lateral shift for nearly all flexion angles. All graft conditions significantly decreased lateral tilt at 0°, with additional significant decreases for the 5 and 0 mm conditions. The 0 mm condition significantly increased the maximum medial pressure at multiple flexion angles, increasing by 57% at 30°, but did not alter the maximum lateral pressure.

CONCLUSIONS

Allowing 5 to 10 mm of patellar lateral translation limits lateral maltracking, thereby decreasing the risk of post-operative recurrent instability. Allowing no patellar translation during graft tensioning reduces maltracking further, but can overconstrain the patella, increasing the pressure applied to medial patellar cartilage already fibrillated or eroded from an instability episode.

Reconstruction of the medial patellotibial ligament results in favorable clinical outcomes: a systematic review

PURPOSE

The medial patellotibial ligament (MPTL), the medial patellofemoral ligament (MPFL), and the medial patellomeniscal ligament (MPML) support the stability of the patellofemoral joint. The purpose of this systematic review was to report the surgical techniques and clinical outcomes of the repair or reconstruction of the MPTL in isolation or concomitant with the MPFL and/or other procedures.

METHODS

A systematic review of the literature was conducted. Inclusion criteria were articles in the English language that reported clinical outcomes of the reconstruction of the MPTL in isolation or in combination with the MPFL and/or other procedures. Included articles were then cross-referenced to find additional journal articles not found in the initial search. The methodological quality of the articles was determined using the Coleman Methodology Score.

RESULTS

Nineteen articles were included detailing the clinical outcomes of 403 knees. The surgical procedures described included hamstrings tenodesis with or without other major procedures, medial transfer of the medial patellar tendon with or without other major procedures and the reconstruction of the MPTL in association with the MPFL. Overall, good and excellent outcomes were achieved in > 75% of cohorts in most studies and redislocations were < 10%, with or without the association of the MPFL. An exception was one study that reported a high failure rate of 82%. Results were consistent across different techniques. The median CMS for the articles was 66 out of 100 (range 30-85).

CONCLUSION

Across different techniques, the outcomes are good with low rates of recurrence, with one article reporting a high rate of recurrence. Quality of the articles is variable, from low to high. Randomized control trials are needed for a better understanding of the indications, surgical techniques, and clinical outcomes. This systematic review suggests that the reconstruction of the MPTL leads to favorable clinical outcomes and supports the role of the procedure as a valid surgical patellar stabilization procedure.

LEVEL OF EVIDENCE

IV: systematic review of level I-IV studies.

Medial patellotibial ligament and medial patellomeniscal ligament: anatomy, imaging, biomechanics, and clinical review

PURPOSE

The purpose of this article is to review anatomical, biomechanical, and clinical data of the medial patellotibial ligament (MPTL) and medial patellomeniscal ligament (MPML), as well as studies focusing on the medial patellofemoral ligament (MPFL) but with relevant data about the MPTL and MPML.

METHODS

A literature search of articles specifically addressing the MPTL and/or MPML was included along with studies focusing on the MPFL but with relevant data about the MPTL and MPML.

RESULTS

The medial patellar ligaments responsible for maintaining the stability of the patellofemoral (PF) joint include the MPFL, the MPTL, and the MPML. The MPFL is considered the primary restraint to lateral patellar translation, while the latter two are considered secondary restraints. There is robust literature on the anatomical, imaging, and biomechanical characteristics of the MPFL, and also the clinical outcome of its injury and surgical reconstruction; much less is known about the MPTL and MPML. Isolated MPFL reconstruction has good clinical and functional outcomes, with a low failure rate when defined as frank re-dislocation. Complications, including continued episodes of patellar apprehension and subluxation, remain present in most series. In addition, the current literature primarily includes a homogeneous population with few excessive anatomic dysplastic factors. There is lack of knowledge on the role of MPTL and MPML in (potentially) aiding patella stabilization and improving clinical outcomes. Understanding the role of the medial-sided patellar ligaments, in particular the role of the secondary stabilizers, in PF function and injury will aid in this goal.

CONCLUSION

MPTL and MPML have consistent basic science literature, as well as favorable clinical outcomes of surgical patellar stabilization with reconstruction of the MPTL. However, there is much heterogeneity among clinical case series and lack of comparative studies to allow clear indication for the role of isolated or combined surgical reconstruction in patellar stabilization. Therefore, this comprehensive review helps understand the current knowledge and the possible applications in the orthopedic clinical practice.

LEVEL OF EVIDENCE

V.

Long-term outcomes after combined arthroscopic medial reefing and lateral release in patients with recurrent patellar instability - a retrospective analysis

Background

There is currently no consensus regarding the optimal surgical treatment method for patients with recurrent patella instability. Our goal was to evaluate the long-term results of combined arthroscopic medial reefing and lateral release, to identify possible risk factors for recurrent dislocations and residual complaints after surgical treatment and to assess functional outcome.

Methods

We performed a retrospective study of 38 patients (43 knees) treated with all-inside technique between 2001 and 2010. The functional outcome was evaluated with the Kujala score, while pain intensity was scored on a visual analogue scale (VAS). Contingency tables were analysed with Fisher’s exact test. Non-parametric analyses were carried out with the Mann-Whitney U and the Wilcoxon signed-rank test. Survival curves were calculated with the Kaplan-Meier method and compared with the log-rank test.

Results

The median age at surgery was 16 years (range, 9–44 years) and the median follow-up amounted to 9.7 years (range, 4.7–14.7 years). Residual complaints were present in 34 cases (79%). Patients with residual complaints had a trend for a higher body mass index (BMI) at surgery (25.7 vs. 21.6, P = .086). Twenty-two cases had recurrent dislocation after a median interval of 30 months. The probability of recurrent dislocations amounted to 16% after 1 year and 52% after 10 years. There were no significant differences in the presence of residual complaints (P = .721) and median VAS score (P = .313) between patients with or without recurrent dislocation. Patients with recurrent dislocations had a trend towards younger age at surgery (15 vs. 18 years, P = .076). The median Kujala score of the affected knee was 81. Patients with recurrent dislocations had a significantly lower score compared to patients without recurrent dislocations (67 vs. 91, P < .001).

Conclusions

The combined arthroscopic lateral release with medial reefing does not appear to be an adequate treatment for patients with chronic patellar instability in long-term follow-up. Younger patients might be at a higher risk for recurrent dislocations, while a higher BMI at surgery might be associated with residual complaints.

Cadaveric study of the secondary medial patellar restraints: patellotibial and patellomeniscal ligaments

PURPOSE

To detail the anatomy of the medial patella stabilizers, medial patellotibial (MPTL), and medial patellomeniscal ligaments (MPML), focusing on the points of origin and insertion, length, thickness, width, and fibres orientation to study the frequency of anatomical variations and the anatomy of these ligaments, thereby improving surgical techniques.

METHODS

Thirty dissected knees were analysed. A digital caliper was used to measure the length, thickness, and width, as well as the mid-point of the ligaments insertion and the distance from the MPTL insertion to the articular surface of the tibia. The angle of inclination of the ligaments was calculated in the coronal plane. The collected data were tabulated and statistically analysed.

RESULTS

MPTL was present in 90 % as a visible thickening of the deep medial retinaculum and exhibiting only one anatomical variation. The MPML was absent in one of the dissected knees, and one anatomical variation was found. The tilt angle of the ligaments was very similar, with an average of 22.2° ± 7.6° for the MPTL and 24.2° ± 6.6° for the MPML.

CONCLUSION

The MPTL is a long visible structure of the deep layer of the medial retinaculum, but with a distinct origin and insertion. The MPML is thicker with an angular direction similar to MPTL. The presence of these ligaments in most of the specimens studied suggests that the real anatomical and biomechanical importance of these ligaments should be further investigated because they play a role in the patellar stability.

Reconstruction of the Medial Patellofemoral Ligament Using a Synthetic Graft With Arthroscopic Control of Patellofemoral Congruence

PURPOSE

To compare the results of reconstruction of the medial patellofemoral ligament (MPFL) using a synthetic graft (Poly-Tape) between knee joints in which the patella was reduced to the strict center and those in which it was slightly lateral to the center of the trochlea to determine whether patellar position within this range affects the results.

METHODS

Forty-six knee joints in 46 patients were examined retrospectively with a minimum follow-up of 2 years. The position of the patellar central ridge in the trochlea on arthroscopy immediately after reconstruction of the MPFL was measured. The joints were classified into group 1 (6 male and 12 female patients), in which the patella was reduced to the strict center of the trochlea, and group 2 (10 male and 18 female patients), in which the patella was reduced slightly lateral to the center. The mean age was 20.7 years in group 1 and 20.3 years in group 2. Knee joints were assessed using the Kujala score and the International Knee Documentation Committee (IKDC) subjective evaluation score.

RESULTS

The mean Kujala and IKDC scores improved significantly in both groups after surgery (both P < .001). There was no significant difference between the groups for any assessment before surgery or in the Kujala score after surgery (P = .075). However, the IKDC score after surgery was significantly better in group 2 (91.3 ± 9.1) than in group 1 (82.8 ± 13.1) (P = .012).

CONCLUSIONS

When recurrent dislocation of the patella was treated with MPFL reconstruction using a synthetic graft, subjective evaluations were better in knee joints in which the patella was repositioned slightly lateral to the center of the trochlea than in those in which the patella was reduced to the strict center, although there was no significant difference in knee function between them.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Malrotation deformities of the lower extremity and implications on total knee arthroplasty: a narrative review

INTRODUCTION

Total knee arthroplasty (TKA) is a successful procedure for the management of osteoarthritis (OA) of the knee. Axial plane deformities are more common than suspected in patients presenting with osteoarthritis of the knee joint. Recent research has indicated that torsional deformities could play an important role in the development of anterior knee pain (AKP).

METHODS

In a narrative review of the literature, the aetiology of maltorsion deformity of the lower extremity in both, childhood and adulthood, as well as the development of postoperative femoral axial plane deformities are examined. This includes the numerous surgical interventions that have been described for the treatment of maltorsion syndrome, and the role of patient-specific instrumentation. Finally, correcting for maltorsion deformity during and its potential implications for the current clinical care pathway, in terms of both pre- and perioperative practices is discussed.

DISCUSSION AND CONCLUSION

Axial plane alignment is considered the 'third dimension' in TKA. Correct axial alignment the lower extremity and of prosthetic components is deemed an important prerequisite for a postoperatively stable and painless knee. Identification of and, where appropriate, adjustment for any pre-existing maltorsion deformities is thought to significantly reduce the proportion of patients with residual complaints following TKA. Well-designed and well-conducted clinical studies are required to support our hypotheses.

Medial Patellofemoral Ligament Reconstruction Combined With Bony Procedures for Patellar Instability: Current Indications, Outcomes, and Complications

PURPOSE

The aim of this literature review is to analyze current indications, outcomes, and complication rates of medial patellofemoral ligament (MPFL) reconstruction associated with bony procedures in order to clarify efficacy and adoptability in selected patients with patellar instability.

METHODS

A systematic review of the literature was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search on PubMed, Medline, CINAHL, Cochrane, Embase, and Google Scholar databases was performed, using various combinations of the keywords patellar instability, MPFL reconstruction, tibial tubercle osteotomy, and trochleoplasty.

RESULTS

Fourteen of 501 articles were included. Indications for surgery included dysplasia and malalignment. All studies reported significant improvements in overall clinical outcomes. The most frequently used score was the Kujala score, with a mean value of 83.26. Functional failures ranged from 0% to 8.8%. Major complications were not described. Minor complications ranged from 0% to 40%. Reoperations ranged from 4.5% to 17.7%.

CONCLUSIONS

A combined approach seems indicated in patients with patellar instability, especially among those with high tibial tuberosity-trochlear groove or severe trochlea dysplasia. Indications for combined MPFL and bony procedure are influenced by anatomy, including dysplasia and malalignment. We are unable to identify an absolute indication. Bony procedures are associated with increased morbidity.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I to IV studies.

Medial Patellofemoral Ligament Reconstruction With Concomitant Tibial Tubercle Transfer: A Systematic Review of Outcomes and Complications

PURPOSE

To examine the outcomes and complications of medial patellofemoral ligament (MPFL) reconstruction and concomitant tibial tubercle (TT) transfer.

METHODS

A systematic review of published literature on MPFL reconstruction and TT transfer was performed using the following databases: PubMed/Medline, CINAHL (Cumulative Index to Nursing and Allied Health Literature), SPORTDiscus, and Cochrane. To be included, studies were required to present outcomes and/or complication data for MPFL reconstruction performed in combination with TT transfer. Each study was assessed for quality and level of evidence.

RESULTS

Five studies consisting of 92 knees met the inclusion criteria. Between 57% and 77% of the patients were female patients, and the mean age at surgery was 20.6 years (range, 19 to 31 years). The mean follow-up period was 38 months (range, 23 to 53 months). Postoperative outcome measures including the Lysholm score, Kujala score, International Knee Documentation Committee score, Knee Injury and Osteoarthritis Outcome Score, and visual analog scale score were similar to those previously reported for isolated MPFL reconstruction. Reported complication rates were lower than 15% and included wound infection, hardware irritation, and stiffness. Four studies were graded as Level IV evidence, and 1 study was graded as Level II evidence. Only 1 study scored greater than 50% in the quality analysis.

CONCLUSIONS

Results from the analyzed studies indicate that MPFL reconstruction combined with TT transfer is a safe and effective procedure, with a low to moderate risk of complications but overall favorable results. TT transfer is most often performed in conjunction with MPFL reconstruction in the setting of malalignment such as an increased TT-to-trochlear groove distance, and although the surgical indications may differ, the outcomes and risk profiles are similar to those of isolated MPFL reconstruction. With the recognition that these patients are difficult to standardize, additional well-designed studies are needed to further investigate the ideal surgical candidates for MPFL reconstruction with concomitant TT transfer.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II and IV studies.