Techniques of medial retinacular repair and reconstruction

Palpation and fluoroscopy are valid but unreliable for the assessment of femoral tunnel position after medial patellofemoral ligament reconstruction

OBJECTIVES

The purpose of this study was to evaluate the validity and reliability of two techniques, palpation and fluoroscopy, for assessing medial patellofemoral ligament (MPFL) reconstruction femoral tunnel position accuracy.

METHODS

Twenty-one fresh frozen cadaveric knees had an MPFL femoral tunnel drilled and filled with a metal screw. Tunnels were created in a nonstandard fashion to ensure the sample included a range of tunnel positions from poor to ideal. Six experienced sport medicine and arthroscopy surgeons evaluated the placement of the femoral tunnel by palpating the screw in relation to anatomic landmarks and by fluoroscopy related to Schöttle's Point. They evaluated 1) the accuracy of femoral tunnel placement, 2) the direction of tunnel error, and 3) the clinical acceptability of the tunnel position. Validity measures included sensitivity, specificity, and correlation to clinical acceptability, which were calculated for the palpation and fluoroscopic assessments. Reliability measures included interrater reliability (ICC 2,k) for femoral tunnel accuracy and percent agreement of the raters' tunnel direction assessment.

RESULTS

The palpation method demonstrated a sensitivity of 0.79 and specificity of 0.84 for assessing the accuracy of femoral tunnel placement, while the fluoroscopic method showed a sensitivity of 0.83 and specificity of 0.92. Pearson correlation coefficients for clinical acceptability of tunnel position were high, with both techniques ranging from .589 to .854. Interrater reliability for the palpation and fluoroscopic techniques for assessment of tunnel accuracy were 0.31 and 0.55 (ICC 2,k), respectively. Assessment of the direction of tunnel error was good with the fluoroscopic technique slightly more accurate than palpation.

CONCLUSION

This study demonstrated that both palpation and fluoroscopy are valid techniques for assessing femoral tunnel position after MPFL reconstruction. Despite demonstrating good validity, the accuracy of assessing tunnel position was unreliable in a group of six experienced knee surgeons. Further research into MPFL reconstruction femoral tunnel assessment techniques, including patient-specific reference standards, is warranted.

LEVEL OF EVIDENCE

Level 2.

Nonanatomical femoral tunnel positioning in isolated MPFL reconstruction is not associated with an increased risk of patellofemoral osteoarthritis after a minimum follow-up of 10 years

PURPOSE

The association between the prevalence of patellofemoral arthritis (PFA) and femoral tunnel positioning following isolated medial patellofemoral ligament reconstruction (MPFLr) has not been well described. The aim of this study was to analyse the relationship between femoral tunnel positioning and the prevalence of PFA.

METHODS

This was a single-centre study of patients undergoing an isolated MPFLr between 2006 and 2011 with a minimum of 10 years of follow-up. Outcomes assessed were the presence of PFA on radiographs, recurrence of instability requiring revision surgery and patient-reported outcomes, including Kujala, Tegner and IKDC scores. Tunnel positioning was assessed on postoperative radiographs using two radiographic methods: Schöttle's point and the grid method to localise the femoral tunnel. Patients were grouped based on tunnel positioning and compared.

RESULTS

Fifty patients were analysed at a mean follow-up of 12.4 years. Thirty-three patients (66%) had a femoral tunnel position within 7 mm of Schöttle's point and 39 (78%) within the anatomic quadrant, with the most common location according to the grid method in D4 (28%) and E4 (26%), respectively. Thirty-seven patients (74%) had a satisfactory (>80 versus <80) Kujala score at long-term follow-up. None of the examined tunnel assessment methods demonstrated a significant relationship with Tegner, Kujala or International Knee Documentation Committee scores. Patients with a femoral tunnel position >7 mm outside Schöttle's point or were considered to be in a nonanatomic position were not significantly more likely to result in unsatisfactory Kujala scores at the last follow-up. Tunnel positioning and the other tested parameters were not found to be significantly associated with the development of PFA.

CONCLUSION

No correlation between femoral tunnel position and risk of PFA or poor outcomes was observed in patients undergoing isolated MPFLr at long-term follow-up. The impact of femoral tunnel placement on long-term outcomes in patients with PFI may be less significant than originally considered.

LEVEL OF EVIDENCE

Level IV.

Isolated MPFL reconstruction with soft tissue femoral fixation technique in 54 skeletally immature patients: Clinical outcomes at 2 years follow-up. A French multicenter retrospective study

BACKGROUND

Medial patello-femoral ligament (MPFL) reconstruction is one of the therapeutic options to treat patellofemoral instability. Classically, a à la carte treatment of skeletal and ligament abnormalities is described. This option is difficult to achieve in children because bony procedures can damage the femoral and/or tibial growth plate. The objective was to evaluate a strategy for isolated reconstruction of the MPFL in the treatment of objective patellar instabilities in children, in a large cohort. The return to sport, knee function and pain or discomfort were studied as secondary endpoints.

METHODS

This French multicenter retrospective study included 54 pediatric patients with objective patellofemoral instability. Patients were included if they had presented at least 2 episodes of objective patella dislocation. A Deie-like technique with gracilis tendon graft, soft tissue femoral fixation and patellar bone tunnels for patellar fixation was used. Recurrence of dislocation was studied as the primary endpoint, and the recurrence rate was compared with the literature. A comparison of functional scores (Kujala, Lille femoro-patellar instability score or LFPI Score and Tegner activity score) and NRS between pre- and postoperative was studied as a secondary objective.

RESULTS

A recurrence of femoro-patellar instability was observed for five patients within 2 years follow up (9%). A significant improvement of the Kujala, LFPI score, Tegner and NRS scores was observed (p<0.001).

CONCLUSION

Isolated reconstruction of the MPFL presents a risk of recurrence of 9% at 2years follow-up. This technique significantly improves the functional scores of the knee. This modified Deie technique provides good clinical and functional results, allowing return to sports with an acceptable risk of recurrence of patellar dislocation, similar to those observed in the literature. Isolated MPFL reconstruction as a first-line treatment appears to be a reliable and effective technique in terms of recurrence of dislocation and functional scores. It allows early recovery and rehabilitation and has lower morbidity than procedures requiring bone gestures.

LEVEL OF EVIDENCE

III, retrospective comparative study.

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.

Reimagined MPFL Reconstruction: Retinacular Fixation of the Doubled Hamstring Graft at the Patella and Suture Anchor-Based Femoral Fixation

Background

Lateral patellar dislocation is frequently observed among teenagers and young adults. There is no consensus on the best type of graft or fixation strategy for the femur and patella, and complications such as iatrogenic patella fracture, tunnel malposition, and grafting failure are common. The objective of our research is to find out the functional outcome of a new method of medial patellofemoral ligament (MPFL) reconstruction, which involves two key components: (1) patellar fixation is accomplished by suturing the two limbs of the looped doubled hamstring graft in a divergent fashion to the retinaculum at the medial border of the upper half of patella and (2) the placement of a suture anchor tied to the graft at the isometric point on the medial femur condyle.

Methods

This study is a retrospective assessment of patients who underwent MPFL reconstruction at our hospital between September 2018 and August 2020. Patients were monitored for at least 2 years after the initial procedure until August 2022.

Results

A total of 29 patients were recruited for the study, with 22 being females and the average age being 30.38 years. During the postoperative period, none of the participants experienced instability, redislocation, patellar/femoral fractures, or abnormal distal femur growth. The Tegner-Lysholm knee score was good to excellent for 17 (58.6%) participants, fair for 10 (34.5%) participants, and poor for 2 (6.9%) participants. The Kujala anterior knee pain score was more than 80 for 19 (65.5%) participants.

Conclusion

This research presents a significant achievement rate of the surgical procedure, accompanied by the mean Tegner-Lysholm knee score of 82.68 and the mean Kujala anterior knee pain score of 82.71. Notably, there were no complications observed in the postoperative period.

The severity of patellar and trochlear dysplasia are correlated

PURPOSE

Patellar instability is a frequent clinical situation in adolescents and young adults. One of the most important risk factors of this condition is trochlea dysplasia. Few studies have analyzed the role of patellar dysplasia. The objective of this paper was to assess the correlation between trochlear and patellar dysplasia. The hypothesis is that patellar dysplasia increased in parallel with femoral trochlear dysplasia.

METHODS

The study included patients operated on at least one knee for patellar instability between 2008 and 2020. For these patients, symptomatic knees (operated or not) were included if they had lateral and patellofemoral skyline radiographs. Two blinded observers categorized each trochlear and patellar dysplasia according to the Dejour and Wiberg classifications. Patellar height was also measured by applying the Caton-Deschamps index.

RESULTS

A total of 100 patients were selected, involving 149 symptomatic knees. A significant correlation between trochlear and patellar dysplasia types was found (0.82; p < 0.0001). Dejour types B and C of trochlear dysplasia were significantly more often associated with patellar dysplasia than Dejour type A (p = 0.033 and p = 0.019, respectively). Moreover, severe Wiberg 3 patellar dysplasia was significantly associated with type D Dejour trochlear dysplasia than with the sum of all other Dejour types taken together (p < 0.0001).

CONCLUSION

This study confirms a linear correlation between the severity of patellar and trochlear dysplasia. Further studies are needed to evaluate the place of patellar dysplasia in the therapeutic strategy.

LEVEL OF EVIDENCE

Level IV.

Changes in Patellar Morphology Following Soft Tissue Surgical Correction of Recurrent Patellar Dislocation in Children with Low-Grade Trochlear Dysplasia

Objective

To investigate the changes in patellar morphology following soft tissue surgical correction of recurrent patellar dislocation in children with low‐grade trochlear dysplasia.

Methods

The prospective cohort study was performed between November 2007 and December 2012. Finally, 25 cases, with the mean age of 8.4 years (range from 7 to 10 years), were admitted to the study. All patients were diagnosed as bilateral recurrent patellar dislocation associated with femoral trochlear dysplasia. The knee that suffered injury or was dislocated was treated with medial patellar retinacular plasty (surgery group). The contralateral knee, which served as a control, was treated conservatively (conservative group). Axial CT scans were undertaken in all patients to assess the patellar morphological characteristics.

Results

The mean follow‐up time was 60.8 months (range 48 to 75 months). Preoperatively, there were no statistically significant differences between the patellar morphology in the two groups (P > 0.05). Many radiological parameters of patellar morphology were significantly different between the two groups at the final follow‐up, including well‐known parameters, such as the mean patellar width (surgery group, 40.58 mm [SD 1.26]; conservative group, 36.41 mm [SD 1.17]; P < 0.05), the mean patellar thickness (surgery group, 11.59 mm [SD 0.74]; conservative group, 9.38 mm [SD 0.56]; P < 0.05) and the mean Wiberg index (surgery group, 0.54 [SD 0.06]; conservative group, 0.72 [SD 0.08]; P < 0.05). There are also little‐known parameters, such as the ratio of length of lateral patella to medial patella (surgery group, 1.26 [SD 0.17]; conservative group, 1.69 [SD 0.21]; P < 0.05), which was a measurement of facet asymmetry. However, the Wiberg angle was not significantly different between the two groups (surgery group, 128.63° [SD 9.05]; conservative group, 125.47° [SD 13.96°]; P > 0.05) at the final follow‐up. No complications were found.

Conclusions

The patellar morphology can be significantly improved by early soft tissue surgical correction in children with patellar instability associated with low‐grade femoral trochlear dysplasia.

The modified semi-tunnel bone bridge technique achieved statistically better knee function than the suture anchor technique

PURPOSE

The purpose of this study was to evaluate and compare the clinical outcomes of two different fixation techniques for anatomic medial patellofemoral ligament (MPFL) reconstruction.

METHODS

A retrospective study was undertaken between 2012 and 2018 of 60 cases of patellar dislocation who underwent surgical reconstruction between 2007 and 2010: 30 patients were treated with modified semi-tunnel bone bridge fixation (group A) and 30 patients with suture anchor fixation (group B). All patients had computed tomography scans available to review the patellar tilt angle and lateral patellar angle (LPA). In addition, a physical examination was performed, and the patellar apprehension sign and patellar stability were evaluated. Knee function was also evaluated using the Kujala score and Lysholm score.

RESULTS

At a minimum 5-year follow-up, the patellar tilt angle and LPA were restored to the normal range, and a significant difference was observed between the groups. There was a significant improvement in knee function in the Kujala and Lysholm scores after surgery in both groups. At the final follow-up, the mean Kujala and Lysholm scores in groups A and B were significantly different.

CONCLUSION

Both the semi-tunnel bone bridge and suture anchor fixation for double-bundle anatomic reconstruction of the MPFL can effectively restore patellar stability and improve knee function. The semi-tunnel bone bridge technique achieved statistically better knee function than the suture anchor technique at a minimum 5-year follow-up.

LEVEL OF EVIDENCE

III.

An Updated Overview of the Anatomy and Function of the Proximal Medial Patellar Restraints (Medial Patellofemoral Ligament and the Medial Quadriceps Tendon Femoral Ligament)

The medial patellofemoral ligament (MPFL) has been widely accepted to function as "the primary static restraint to lateral patellar displacement." However, current growing evidence suggests that there is a complex of medial patellofemoral/tibial ligaments, both proximal [MPFL, and medial quadriceps tendon femoral ligament (MQTFL)], and distal (medial patellotibial ligament and the medial patellomeniscal ligament) which restrain lateral patellar translation at different degrees of knee flexion. Specifically, the MQTFL has gained popularity over the last decade because of pure soft tissue attachments into the extensor mechanism that allow for avoidance of drilling tunnels into the patella during reconstruction. The purpose of this article was to report on the current knowledge (anatomy, biomechanics, diagnosis, indications for surgery, and techniques) on the proximal medial patellar restraints, namely the MPFL and the MQTFL, collectively referred to as the proximal medial patellar restraints.

A polygon-shaped complex appearance of medial patellofemoral ligament with dynamic functional insertion based on an outside-in and inside-out dissection technique

PURPOSE

To describe the unclarified characteristics of medial patellofemoral ligament and its relation to neighboring structures.

METHODS

Sixteen fresh-frozen human knees were dissected in using outside-in and inside-out combined technique. The patellar side attachment was observed from the inside view and femoral side from outside view.

RESULTS

The medial patellofemoral ligament was described a complex and multiconnected structure. The femoral side included the upper and lower portion, of which the upper portion attached on the femur with mean width 7.5 ± 1.1 mm and its superficial fibers extended to the adductor magnus tendon and the medial gastrocnemius tendon, and of which the lower portion appeared a right-triangle connected to the MCL without bony attachment. From inside view, the patellar attachment consisted of the bony and non-bony parts. The width of bony attachment was measured mean 16.3 ± 3.8 mm, and the non-bony attachment was found attached on the vastus intermedius tendon with mean width 21.7 ± 4.8 mm. The average thickness was 0.4 ± 0.1 mm and the length were inside assessed mean 67.9 ± 6.1 mm.

CONCLUSION

The medial patellofemoral ligament which dissected a complicated structure with bony and non-bony attachment and multi-connected to neighboring structures on both patella and femur side appears as a polygon-shaped complex structure.

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.

Double-bundle anatomical medial patellofemoral ligament reconstruction with lateral retinaculum plasty can lead to good outcomes in patients with patellar dislocation

PURPOSE

To evaluate the clinical outcomes of double-bundle anatomical medial patellofemoral ligament (MPFL) reconstruction combined with lateral retinaculum plasty versus isolated MPFL reconstruction for patellar dislocation.

METHODS

From 2011 to 2013, 64 patients underwent either double-bundle anatomical MPFL reconstruction combined with lateral retinaculum plasty (Group A, 32 patients), or isolated MPFL reconstruction (Group B, 32 patients). Clinical evaluations were performed 2 years post-operatively and included determination of the number of patients with patellar redislocation, the patellar tilt angle, lateral patellar shift, subjective symptoms, and functional outcomes as evaluated with the Kujala score and Lysholm score.

RESULTS

No dislocation or subluxation occurred during the 25-month follow-up. Radiographically, the patellar tilt angle was 6.0° ± 1.7° in Group A and 6.7° ± 2.0° in Group B, without a significant difference (n. s). The lateral patellar shift was 8.0 ± 2.6 mm in Group A and 8.5 ± 2.4 mm in Group B (n. s). The mean Kujala score was 91.8 ± 3.7 in Group A and 91.5 ± 3.6 in Group B post-operatively (n. s), and the mean Lysholm score was 92.5 ± 3.8 and 90.8 ± 4.9, respectively (n. s).

CONCLUSIONS

Double-bundle anatomical MPFL reconstruction with lateral retinaculum plasty is a promising procedure that provides a new option for patellar dislocation.

LEVEL OF EVIDENCE

III.

Changes in femoral trochlear morphology following surgical correction of recurrent patellar dislocation associated with trochlear dysplasia in children

Aims

The aim of this study was to investigate the changes in femoral trochlear morphology following surgical correction of recurrent patellar dislocation associated with trochlear dysplasia in children.

Patients and Methods

A total of 23 patients with a mean age of 9.6 years (7 to 11) were included All had bilateral recurrent patellar dislocation associated with femoral trochlear dysplasia. The knee with traumatic dislocation at the time of presentation or that had dislocated most frequently was treated with medial patellar retinacular plasty (Group S). The contralateral knee served as a control and was treated conservatively (Group C). All patients were treated between October 2008 and August 2013. The mean follow-up was 48.7 months (43 to 56). Axial CT scans were undertaken in all patients to assess the trochlear morphological characteristics on a particular axial image which was established at the point with the greatest epicondylar width based on measurements preoperatively and at the final follow-up.

Results

Preoperatively, there were no statistically significant differences between the trochlear morphology in the two groups (sulcus angle, p 0.852; trochlear groove depth, p 0.885; lateral trochlear inclination, p 0.676; lateral-to-medial facet ratio, p 0.468; lateral condylar height, p 0.899; medial condylar height, p 0.816). Many radiological parameters of trochlear morphology were significantly different between the two groups at the final follow-up, including well-known parameters, such as the mean sulcus angle (Group S, 146.27° (sd 7.18); Group C, 160.61° (sd 9.29); p < 0.001), the mean trochlear groove depth (Group S, 6.25 mm (sd 0.41); Group C, 3.48 mm (sd 0.65); p < 0.001) and the mean lateral trochlear inclination (Group S, 20.99° (sd 3.87); Group C, 12.18° (sd 1.85); p < 0.001). Lesser known parameters such as the ratio of the lateral to medial trochlear length (Group S, 1.46 (sd 0.19); Group C, 2.14 (sd 0.42); p < 0.001), which is a measurement of facet asymmetry, and the lateral and medial condylar height were also significantly different between the two groups (p < 0.001).

Conclusion

The femoral trochlear morphology can be improved by early (before epiphyseal closure) surgical correction in children with recurrent patellar dislocation associated with femoral trochlear dysplasia. Cite this article: Bone Joint J 2018;100-B:811–21.

Synthetic versus autologous reconstruction (Syn-VAR) of the medial patellofemoral ligament: a study protocol for a randomised controlled trial

Background

Recurrent patellar instability incidence is 5.8/100,000 population, and recurrent dislocations are reported in the range of 15–80%. Recurrent instability is multifactorial and can be associated with disorder of limb alignment, osseous development, congruity of the patella in the trochlea and soft tissue static and dynamic constraints. The multifactorial aetiology makes management challenging, and a lack studies in a heterogeneous population with robust clinical outcomes compounds this further. The options for medial patellofemoral ligament (MPFL) reconstruction include autologous graft reconstruction with semitendinosus tendon, or synthetic polyester woven grafts. In theory, in the young active patient, the surgeon may wish to preserve the hamstring tendons to reduce postoperative morbidity to the patient, reduce delay in recovery from donor site morbidity and preserve the hamstring tendons. There have been no randomised controlled trials (RCTs) to date that directly compare autologous hamstring and synthetic reconstruction methods. This trial aims to assess the functional outcomes in those undergoing MPFL reconstruction with either autologous hamstring graft reconstruction, or a commercially available synthetic polyester open woven tape.

Methods

Following a power calculation using previous studies as the pilot data, a total of 30 patients will be included in the study. Enrolment is based upon strict inclusion/exclusion criteria outlined in the “Methods”. Participants will be randomized to receive either autograft or synthetic graft reconstruction. We aim to recruit 15 patients to each arm of the study. Surgery is performed by a single consultant surgeon experienced in both reconstructive options, using the default surgical technique for each. A postoperative physiotherapist-directed rehabilitation protocol will be implemented, as is routine. The primary outcome is the Kujala functional score and its change over the study period. Data on further secondary outcomes using validated outcomes scores will also be collected, specifically the Tegner and Lysholm, Banff Patellar Instability Index, and ACL Quality of Life Score. Secondary outcomes are complications and revision for any reason. The patient follow-up time is 2 years. The first patient will be recruited in January 2018. The expected trial deadline for recruitment is December 2018, with records and results being held for 5 years.

Discussion

This RCT study is the first to directly compare the efficacy of autograft versus synthetic allograft in MPFL reconstruction and the graft effects on patient-reported clinical outcomes.

Trial registration

ISRCTN, 16657952. Registered on 3 March 2017.

The study protocol has been approved by the Office for Research Ethics Committees of Northern Ireland (ORECNI 17/NI/0129).

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2622-7) contains supplementary material, which is available to authorized users.

Evaluation of the Schöttle Technique in the Pediatric Knee

Background

The Schöttle point is commonly used for anatomic femoral tunnel placement during medial patellofemoral ligament (MPFL) reconstruction. This technique has not been previously validated in the skeletally immature patient, in whom femoral tunnel placement may put the distal femoral physis at risk of iatrogenic injury.

Hypothesis

Interobserver reliability for femoral tunnel placement will be higher in adult knees compared with pediatric knees.

Study Design

Cross-sectional study (diagnosis); Level of evidence, 3.

Methods

We selected 30 perfect lateral radiographs for this study: 20 from pediatric knees (mean patient age, 10 years; range, 8-11 years) and 10 from adult knees (mean patient age, 18.5 years; range, 18-23 years). Six observers with varying levels of clinical experience evaluated each radiograph and approximated the site of the MPFL femoral tunnel using the Schöttle technique. Intra- and interobserver reliabilities for femoral tunnel placement were evaluated. Statistical analysis was used to compare measurements.

Results

During initial interobserver measurements, the diameter of the composite perfect circles averaged 9.0 and 6.8 mm in adult and pediatric knees, respectively (P = .004). At repeat measurement, circles averaged 9.8 and 7.3 mm in adult and pediatric knees, respectively (P = .0001). Femoral tunnel placement intraobserver variance averaged 2.9 mm in adult knees (range, 1.9-4.0 mm) and 2.3 mm in pediatric knees (range, 1.9-2.9 mm). This difference was not significant (P = .14).

Conclusion

This study demonstrated that interobserver variance is actually greater in adult knees compared with pediatric knees, although interobserver variance was significantly different for both populations. Additionally, intraobserver variance is small on repeat measures, demonstrating that the Schöttle technique is reproducible for individual observers. Sources of this increased variance between observers are differences in agreement on the bony landmarks required for the Schöttle technique. Due to this variability in tunnel placement, we recommend caution when the Schöttle technique is used in pediatric knees to avoid iatrogenic injury to the distal femoral physis during femoral tunnel placement.

Objective quantification of trochlear dysplasia: Assessment of the difference in morphology between control and chronic patellofemoral instability patients

BACKGROUND

Trochlear dysplasia is an important risk factor associated with patellofemoral instability, but it remains difficult to classify with consistency. Currently there is no objective way to quantify the dysplasia. The purpose of this study is to define and quantify objectively the trochlear morphology by volume and length via computed tomography (CT).

METHODS

One-hundred control patients (136 knees) were retrospectively reviewed and compared to 36 consecutive patients (72 knees) who were treated surgically for recurrent patellar instability and known trochlear dysplasia based on a lateral radiograph. Trochlear morphology was analyzed from a pre-operative CT and data presented as trochlear sulcus volume trochlear length. To determine where along the trochlear length dysplasia is most variable, the trochlear length was radiographically divided into thirds, volume was quantified along that section and compared to control trochlear.

RESULTS

A significant difference in trochlear morphology exists between cohorts, volume (1.98 vs 3.77cm³) and length (31.97 vs 34.66mm) (p<0.05). However, there appears to be a gender based difference in trochlea morphology. The trochlea volumetric analysis between the female cohorts (L: 2.02cm³ vs. 2.94cm³, R: 1.95cm³ vs. 2.93cm³) demonstrated significantly less volume in instability patients (p<0.001). The proximal third of the trochlear contributed the majority of dysplasia difference determined by comparing mean trochlear volume, 95% of the difference. This difference decreased in distal sections, 53% and 32% respectively.

CONCLUSION

This reproducible technique can be used to quantify the trochlea morphology, in order to describe the severity of a dysplasia.

Biomechanical tensile strength analysis for medial patellofemoral ligament reconstruction

BACKGROUND

Medial patellofemoral ligament (MPFL) reconstruction is a surgery for acute and chronic dislocating patella. Several surgical techniques have been described. No biomechanical study has compared suture anchors, interference screws, and suspensory cortical fixation for MPFL reconstruction using human gracilis allograft.

METHODS

Twelve human cadaver knees were used for the analysis of five MPFL reconstruction techniques on the femur (F) and patella (P): suspensory cortical (SC), interference screw (IS) and suture anchor (SA) fixation (SC-F/SC-P, SC-F/IS-P, SC-F/SA-P, IS-F/SC-P, IS-F/IS-P). Each method was examined six times, each using a new human gracilis allograft. The force necessary for 50% patellar displacement and 100% patellar displacement were recorded for each method. Additionally, we examined the peak force to fixation failure for all methods. Patella dislocation or loss of fixation was considered failure.

RESULTS

SC-F/SC-P, IS-F/SC-P, and SC-F/IS-P required force to failure greater than that of the native MPFL. The SC-F/IS-P required the largest force to failure. The SC-F/SA-P fixation technique required significantly less force to failure (P<0.05) than the native MPFL and significantly less force to failure (P<0.05) than all four other fixation techniques. All methods of fixation employing an interference screw failed secondary to graft pullout at the interference screw-bone interface. Methods employing suture anchors and two suspensory cortical fixations failed at the graft-suture anastomosis.

CONCLUSION

SC-F/SC-P, IS-F/SC-P, and SC-F/IS-P fixations were found to be stronger than the native MPFL, with the strongest being SC-F/IS-P.

Medial Patellofemoral Ligament Repair Versus Reconstruction for Recurrent Patellar Instability: Two-Year Results of an Algorithm-Based Approach

Background:

Patellar instability remains a challenging problem for both the patient and surgeon. Medial patellofemoral ligament (MPFL) repair has historically had poor results, and due to this, there is currently a trend toward reconstruction.

Purpose/Hypothesis:

This study was undertaken to investigate experience with repair versus reconstruction of the MPFL using a multifactorial treatment algorithm approach. Our hypothesis was that there will be no significant difference in outcome scores between patients in the MPFL repair and reconstruction groups.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 24 patients with recurrent (≥2) lateral patellar dislocations were included. All had failed nonoperative treatment for more than 6 months, and all were observed for a minimum of 2 years. First, magnetic resonance imaging (MRI) was used to find the location of the MPFL tear. A tilt test was used to determine whether a lateral retinacular lengthening was required to allow the patella to have neutral tilt. If the MRI showed a tibial tubercle–trochlear groove (TT-TG) distance greater than 20 mm, a tibial tubercle osteotomy (TTO) was recommended. An MPFL reconstruction was performed if the entire ligament was inadequately visualized on MRI or if it was torn from both insertion sites. Failure was defined as recurrent lateral patellar instability after surgery. As a secondary outcome measure, Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm score, and Tegner score were calculated.

Results:

All patients were evaluated with a mean follow-up of 51 months (range, 25-79 months). Sixteen patients initially underwent MPFL repair, 8 underwent reconstruction, and 3 also underwent TTO. MPFL reconstructions were performed in all patients who underwent TTO. One MPFL repair was to the anatomic femoral origin and 15 were to the patellar insertion corresponding to the site of tearing on MRI. A lateral retinacular lengthening was performed in 21 patients. There was 1 failure in the repair group (6%) and none in the reconstruction group. However, the patient who failed had a TT-TG distance of 26 mm but refused a TTO. She subsequently underwent revision with a TTO and MPFL reconstruction and did not have any further instability events. There were no significant differences between groups for any of the secondary outcome scores.

Conclusion:

Using an algorithm-based approach, MPFL repair or reconstruction may lead to clinically acceptable results at 2-year follow-up.

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.

An Algorithmic Approach to the Management of Recurrent Lateral Patellar Dislocation

High-level evidence supports nonoperative treatment for first-time lateral acute patellar dislocations. Surgical intervention is often indicated for recurrent dislocations. Recurrent instability is often multifactorial and can be the result of a combination of coronal limb malalignment, patella alta, malrotation secondary to internal femoral or external tibial torsion, a dysplastic trochlea, or disrupted and weakened medial soft tissue, including the medial patellofemoral ligament (MPFL) and the vastus medialis obliquus. MPFL reconstruction requires precise graft placement for restoration of anatomy and minimal graft tension. MPFL reconstruction is safe to perform in skeletally immature patients and in revision surgical settings. Distal realignment procedures should be implemented in recurrent instability associated with patella alta, increased tibial tubercle-trochlear groove distances, and lateral and distal patellar chondrosis. Groove-deepening trochleoplasty for Dejour type-B and type-D dysplasia or a lateral elevation or proximal recession trochleoplasty for Dejour type-C dysplasia may be a component of the treatment algorithm; however, clinical outcome data are lacking. In addition, trochleoplasty is technically challenging and has a risk of substantial complications.

Surgical reconstruction of the medial patellofemoral ligament

Various treatments for patellofemoral instability have been proposed, such as lowering or medialization of the tibial tubercle, division of the lateral retinaculum, plication of the medial retinaculum, lowering of the vastus medialis, and trochleoplasty. However, it has been difficult to analyze the outcomes of each technique because they are often performed in combination. Recent anatomical and biomechanical studies have shown that the medial patellofemoral ligament (MPFL) is the primary stabilizer of the patella between full extension and 30° flexion. For this reason, reconstructing this ligament is relevant, reinforced by promising early clinical results. MPFL reconstruction techniques differ in the graft used and the fixation method. They will be described here as a function of their fixation method, either into bone or soft tissue. The technical challenges, advantages and disadvantages of these different techniques are reviewed in detail, along with the postoperative rehabilitation protocol. Strict technique is needed to prevent postoperative complications, with flexion contracture due to excessive graft tension being the most common complication. Recurrence of the instability is rare after surgery, proof of the dependable nature of these reconstruction procedures.

MEDIAL PATELLOFEMORAL LIGAMENT RECONSTRUCTION TO TREAT RECURRENT PATELLAR DISLOCATION

OBJECTIVE

To present a new technique for reconstruction of the medial patellofemoral ligament (MPFL) in patients with recurrent patellar dislocation and to evaluate the clinical findings from this.

METHODS

Between January 2007 and January 2008, 23 patients underwent reconstruction of the MPFL with a free graft from the semitendinosus tendon. After a minimum of 24 months of follow-up, 22 patients were evaluated using the Kujala and Lysholm clinical protocols.

RESULTS

The mean follow up was 26.2 months. According to the Lysholm protocol, the patients had a mean score of 53.72 points preoperatively and 93.36 points postoperatively (p = 0.000006). According to the Kujala protocol, the mean score was 59.81 points preoperatively and 83.54 points postoperatively (p = 0.002173).

CONCLUSION

Reconstruction of the medial patellofemoral ligament using the proposed technique showed excellent results over the short term, when evaluated by means of clinical protocols.

BIOMECHANICAL ACCESS METHOD FOR ANALYZING ISOMETRICITY IN RECONSTRUCTING THE MEDIAL PATELLOFEMORAL LIGAMENT

OBJECTIVE

To present a biomechanical device for evaluating medial patellofemoral ligament (MPFL) reconstruction and its isometricity.

METHODS

An accessible biomechanical method that allowed application of physiological and non-physiological forces to the knee using a mechanical arm and application of weights and counterweights was developed, so as to enable many different evaluations and have a very accurate measurement system for distances between different structures, for analysis on experiments. This article describes the assembly of this system, and suggests some practical applications. Six cadaver knees were studied. The knees were prepared in a testing machine developed at the Biomechanics Laboratory of IOT-HCFMUSP, which allowed dynamic evaluation of patellar behavior, with quantification of patellar lateralization between 0° and 120°. The differences between the distances found with and without load applied to the patella were grouped according to the graft fixation angle (0°, 30°, 60° or 90°) and knee position (intact, damaged or reconstructed).

RESULTS

There was a tendency for smaller lateral displacement to occur at fixation angles greater than 30 degrees of flexion, especially between the angles of 45° and 60° degrees of flexion, after the reconstruction. For the other angles, there was no statistical significance.

CONCLUSION

The method developed is a useful tool for studies on the patellofemoral joint and the MPFL, and has a very accurate measurement system for distances between different structures. It can be used in institutions with fewer resources available.

Clinical-radiographic correlation of the femoral insertion point of the graft in reconstruction of the medial patellofemoral ligament

OBJECTIVE

To analyze the radiographic positioning of the femoral tunnel and correlate this with the postoperative clinical results among patients undergoing reconstruction of the medial patellofemoral ligament (MPFL) alone.

METHOD

This was a retrospective study in which 30 knees of 26 patients with recurrent dislocation of the patella that underwent MPFL reconstruction were evaluated. The femoral insertion point of the graft and the postoperative clinical condition were analyzed and correlated using the Kujala and Lysholm scales.

RESULTS

22 knees presented a femoral tunnel in the anatomical area (group A) and 8 outside of this location (group B). In group A, the mean score on the Kujala scale was 89.68 points and on the Lysholm scale was 92.45 points. In group B, the mean score on the Kujala scale was 84.75 points and on the Lysholm scale was 92 points. The difference between the means was not significant on either of the two scales.

CONCLUSION

Correlation with the clinical results did not show any difference in relation to the positioning of the femoral insertion of the graft.

Does severity of femoral trochlear dysplasia affect outcome in patellofemoral instability treated by medial patellofemoral ligament reconstruction and anterior tibial tuberosity transfer?

INTRODUCTION

Medial patellofemoral ligament (MPFL) reconstruction associated to anterior tibial tuberosity transfer (ATTT) is recommended in objective patellofemoral instability (PFI). Efficacy, however, has not been precisely determined in trochlear dysplasia with spur. A case-control study was performed in a PFI population, comparing groups with trochlear dysplasia with and without spur (S+ vs. S-) to assess the impact of trochlear dysplasia on (1) patellofemoral stability, (2) functional results and complications, and (3) patellofemoral cartilage status on MRI.

HYPOTHESIS

Trochlear spur does not affect outcome in PFI managed by MPFL reconstruction and ATTT.

MATERIAL AND METHODS

Twenty-eight knees (26 patients) with PFI were analyzed retrospectively and divided into 2 groups of 14 knees each according to presence of trochlear spur (S+ vs. S-). All 28 knees had undergone ATTT and MPFL reconstruction by semitendinosus autograft. Results were assessed on Lille and IKDC functional scores, and cartilage status was determined on MRI at last follow-up.

RESULTS

At a mean 24 months' follow-up (range, 12-52 months), there was no recurrence of dislocation. IKDC and Lille scores tended to improve in both groups, although the only significant improvement was in IKDC score (S- gain, 21.3±16; S+ gain, 18.1±14) (P=0.01). IKDC scores at last follow-up were better in the S+ than S- group (79±19 [range, 21-92] vs. 68±13 [range, 35-84], respectively; P=0.012). Lille scores showed no significant inter-group differences in mean gain (P=0.492) or mean value (P=0.381). The S+ group showed more cartilage lesions (n=14/14 knees, including 12/14 with grade≥2 lesions) than the S- group (n=9/14 knees, all grade≤2).

CONCLUSION

MPFL reconstruction with ATTT provided good short-term patellofemoral stability independently of the severity of trochlear dysplasia. Functional results and gain on IKDC, however, were poorer in case of dysplasia with trochlear spur. This is probably due to cartilage lesions, observed more frequently pre- and post-operatively in the spur group, especially as there was no significant difference in Lille Score, which highlights stability.

LEVEL OF EVIDENCE

III, retrospective case-control study.

The relationship of the femoral physis and the medial patellofemoral ligament in children: a cadaveric study

BACKGROUND

Patellar dislocations are common in skeletally immature athletes, and the medial patellofemoral ligament (MPFL) is an important primary restraint to lateral patellar translation. The relationship between the MPFL femoral origin footprint and femoral physis is unclear. The purpose of this study was to evaluate the MPFL femoral origin footprint and its relationship to the femoral physis in skeletally immature anatomic specimens.

METHODS

Six skeletally immature cadaver knee specimens were examined through gross dissection (group A: 1, 11, and 11 mo; and group B: 8, 10, and 11 y). Metallic markers were placed at the center of the MPFL femoral origin footprint. Computed tomography scans for each specimen were analyzed. The MPFL footprint width, and the vertical distances from the center and proximal extent of the MPFL footprint to the medial aspect of the physis were measured.

RESULTS

The mean width of the MPFL femoral origin footprint was 0.70 cm (0.48 to 1.09 cm) and 1.12 cm (1.03 to 1.29 cm) for groups A and B, respectively. The mean distance from the center of the MPFL origin footprint to medial aspect of the distal femoral physis was 0.90 cm (0.52 to 1.30 cm) and 0.40 cm (0.00 to 0.86 cm) distal to the physis for groups A and B, respectively. The mean distance from the proximal extent of the MPFL origin footprint to the medial aspect of the femoral physis was -0.55 cm (-0.28 to -1.03 cm) and 0.16 cm (-0.34 to 0.64 cm) for groups A and B, respectively.

CONCLUSIONS

All subjects were found to have a center of the MPFL origin footprint at or below the physis. The proximal extent of the MPFL origin footprint was found to extend above the physis in the 2 older specimens.

CLINICAL RELEVANCE

The relationship of the MPFL origin footprint to the femoral physis in the skeletally immature is not well understood. These dissections may be useful to surgeons performing MPFL reconstructions in skeletally immature patients.

Medial patellofemoral ligament reconstruction for patellar maltracking following total knee arthroplasty is effective

PURPOSE

Maltracking of the patella after total knee arthroplasty (TKA) remains a well-recognized problem. The medial patellofemoral ligament (MPFL) has shown to be important for patellar stabilization and reconstructions of the MPFL have already shown excellent functional outcomes for patellar instability of the native knee. Nevertheless, there is only limited literature on using an MPFL reconstruction for correction of patellar maltracking after TKA. In this retrospective study, a consecutive case series was evaluated.

METHODS

Between 2007 and 2010, nine patients (nine knees) with anterior knee pain and symptomatic (sub)luxations of the patella after primary or revision TKA were treated by reconstruction of the MPFL in combination with a lateral release. In two cases, an additional tibial tuberosity transfer was performed, due to insufficient per-operative correction. Pre-operative work-up included a CT scan to rule out component malrotation and disorders in limb alignment. Pre- and post-operative patellar displacement and lateral patellar tilt were measured on axial radiographs. Clinical outcome was evaluated using the visual analogue scale (VAS) satisfaction, VAS pain, dislocation rate and Bartlett patella score.

RESULTS

Median patellar displacement improved from 29 mm (0-44) to 0 mm (0-9) post-operatively. Median lateral patellar tilt was 45° (23-62) pre-operative and changed to a median 15° (-3 to 21) post-operative. Median VAS satisfaction was 8 (5-9) and only one patient reported a subluxing feeling afterwards. The Bartlett patella score displayed a diverse picture.

CONCLUSIONS

Patellar maltracking after primary or revision TKA without malrotation can effectively be treated by MPFL reconstruction in combination with a lateral release. Only in limited cases, an additional tibial tuberosity transfer is needed.

LEVEL OF EVIDENCE

IV.

A simple technique for reconstruction of medial patellofemoral ligament with bone-fascia tunnel fixation at the medial margin of the patella: a 6-year-minimum follow-up study

Background

Medial patellofemoral ligament (MPFL) reconstruction has become an accepted technique to treat patellofemoral instability, and numerous surgical techniques have been described to reconstruct the MPFL. We describe a MPFL reconstruction procedure where bone-fascia tunnel fixation occurs at the medial margin of the patella for recurrent patellar dislocation.

Objective

MPFL reconstruction is the preferred operative treatment for recurrent patellar dislocation. The purpose of this study was to report a simple technique for reconstruction of medial patellofemoral ligament with bone-fascia tunnel fixation at the medial margin of the patella for recurrent patellar dislocation and to evaluate the results at 6-year-minimum follow-up.

Methods

The study included 65 patients (28 males, 37 females; mean age, 29.4 ± 5.6 years) who underwent MPFL reconstruction using the bone-fascia tunnel fixation at the medial margin of the patella technique and who were followed for a mean duration of 78.5 ± 3.8 months. Objective assessment, Kujala scale, Lysholm score, and Tegner activity score were obtained preoperatively and at the time of final follow-up.

Results

There were no patellar complications, including redislocation, in the present study. The congruence angle had significant improvement from 19.2° ± 6.3° before surgery to −6.03° ± 0.50° at the last follow-up. The lateral patellar angle had significant improvement from −6.9° ± 3.5° before surgery to 5.1° ± 2.4° at the last follow-up. The patellar tilt angle had significant improvement from 24.5° ± 5.2° before surgery to 12.30° ± 1.90° at the last follow-up. The Kujala score was significantly increased from 52.9 ± 3.2 points preoperatively to 90.1 ± 5.8 points postoperatively (P < 0.05). The mean Lysholm score was significantly increased from 47.2 ± 5.2 to 92.5 ± 6.2 points postoperatively (P < 0.05). The Tegner activity score improved overall from 3.1 ± 0.6 points to 5.8 ± 0.9 points at follow-up.

Conclusion

We have done a simple technique where the MPFL is reconstructed safely to avoid patella fracture, anatomically to restore physiological kinematics and stability, and economically to reduce costs with bone-fascia tunnel fixation at the medial margin of the patella.

Reconstruction of the medial patellofemoral ligament using hamstring tendon graft with different methods: a biomechanical study

OBJECTIVE

To measure the tensile strength of the normal medial patellofemoral ligament (MPFL), and evaluate the biomechanics of different fixation methods of the hamstring tendon graft on the patella.

METHODS

Eight fresh cadaver knees were prepared by isolating the patella, leaving only the MPFL as its attachment to the medial condyle of femur. The MPFL was reconstructed by three different methods: four-suture fixation, anchors-single suture fixation, and anchors-double suture fixation. The tensile strength and the elongation of the normal MPFL and the tendon grafts were measured.

RESULTS

The tensile strength of the four-suture fixation group (234.86±49.02 N) was stronger than that of the normal MPFL (146.91±25.30 N, P=0.0014) and the anchors-single suture group (159.17±49.07 N, P=0.0077), while weaker than that of the anchors-double suture group (314.74±78.46 N, P=0.0052) CONCLUSIONS: With regard to the tensile strength, the four-suture fixation method is reliable for clinical use. Compared with the anchor-suture method, the four-suture fixation method which has no specific implants is more economical, convenient and efficient.

Medial reefing without lateral release for recurrent patellar instability: midterm and long-term outcomes

BACKGROUND

There is no consensus on the optimal surgical technique for recurrent patellofemoral instability. Despite many different surgical procedures discussed in the literature, there are few studies with long-term outcomes.

HYPOTHESIS/PURPOSE

The purpose of this study was to compare subjective and objective preoperative data from patients with recurrent patellar instability and normal alignment to midterm and long-term outcomes after an arthroscopically assisted medial reefing technique. The hypothesis was that the previously reported successful outcomes at 60 months would be well maintained over time.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 19 patients (20 knees) with recurrent patellar instability and normal bony anatomy underwent arthroscopically assisted medial reefing without lateral release. They were evaluated preoperatively and then at midterm (average, 63 months) and long-term (average, 142 months) follow-ups. Patients underwent a history assessment, physical examination, and radiographic evaluation. Outcomes evaluated included Lysholm and Tegner scores, subjective data, and examination and radiographic findings. Operative reports were reviewed for the presence of chondral lesions. Comparative statistics were utilized (P < .05).

RESULTS

All patients were satisfied with their surgery results and would undergo the procedure again. There was 1 recurrent subluxation and no recurrent dislocations. Subjective symptom scores demonstrated significant improvement from preoperative to midterm and long-term follow-ups for pain, instability, and swelling. Both Lysholm and Tegner scores improved significantly from preoperative to midterm and long-term follow-ups. At long-term follow-up, 70% of the patients reported excellent or good results, 5 patients reported fair results, and 1 patient reported a poor result. However, Tegner activity scores decreased significantly from midterm to long-term follow-ups. Significant improvement from preoperative to midterm and long-term follow-ups was demonstrated in physical examination findings including decreases in patellar apprehension and patellar quadrant glide; however, there was no significant difference in retropatellar pain or range of motion. For radiographic measurements, the lateral patellofemoral angle was significantly improved from preoperative to midterm and long-term follow-ups. At long-term radiographic analysis, 5 knees (25%) had narrowing of the patellofemoral joint space, 10 knees (50%) revealed patellofemoral osteophytes, and 7 knees (35%) demonstrated a medial ossicle. The presence of preoperative chondral lesions resulted in significantly lower Lysholm and Tegner scores and increased findings of osteoarthritis at long-term follow-up.

CONCLUSION

Arthroscopically assisted medial reefing, without lateral release, is an effective long-term treatment for patients with recurrent patellar instability and normal bony anatomy.

Double-bundle anatomical versus single-bundle isometric medial patellofemoral ligament reconstruction for patellar dislocation

PURPOSE

The purpose of this study was to evaluate reconstruction of the medial patellofemoral ligament (MPFL) using the double-bundle anatomical or single-bundle isometric procedure with respect to the patients' clinical outcomes.

METHODS

In this retrospective study, we evaluated the clinical outcome of double-bundle anatomical versus single-bundle isometric reconstruction of the MPFL for patellar dislocation patients. Sixty-three patients were included in this study from August 2004 to January 2008. From August 2004 to September 2006, MPFL reconstruction using a single-bundle isometric technique was performed in 21 patients (26 knees). Since October 2006, the double-bundle anatomical reconstruction of the MPFL has been used as the routine surgical procedure. It was performed in 37 patients (44 knees). Fifty-eight patients (70 knees) could be followed up. According to the different techniques, we divided the patients into two groups: group D with double-bundle anatomical reconstruction (37 patients) and group S with single-bundle isometric reconstruction (21 patients). Clinical evaluation consisted of the number with a patellar re-dislocation, patellar apprehension sign, Kujala score, subjective questionnaire score, the patella lateral shift rate and patellar tilt angle measured by cross-sectional CT scan.

RESULTS

According to the Kujala score and the subjective questionnaire score, the outcome of the double-bundle group was better than the outcome of the single-bundle group especially in the long-term. Patellar re-dislocation occurred in three patients in the group S, while no re-dislocation occurred in the group D. In total, 26.9 % of group S was considered to have patellar instability, compared to 4.54 % of the group D. After operation, the patellar tilt angle (PTA) and the patella lateral shift rate (PLSR) were restored to the normal range, with statistical significance (P < 0.05) compared to the preoperative state.

CONCLUSION

Single- and double-bundle reconstruction of the MPFL can both effectively restore patella stability and improve knee function. However, outcomes in the follow-up period showed that the double-bundle surgery procedure was much better than in single-bundle surgery.

Anatomic study of the attachment of the medial patellofemoral ligament and its characteristic relationships to the vastus intermedius

PURPOSE

The aim of this study was to investigate the attachment of the medial patellofemoral ligament (MPFL) using cadaver specimens and establish an anatomic basis for optimal MPFL reconstruction to achieve better patella stability.

METHODS

Sixteen knees of eight cadavers were used in this study. The relationship of the MPFL with quadriceps muscles was investigated from outside after removal of the distal part of the vastus medialis and the rectus femoris and then evaluated from intra-articular side after release of lateral margin of the vastus lateralis muscle, patella and patella tendon.

RESULTS

The proximal fibres of MPFL were mainly attached to the vastus intermedius tendon, without tight adhesion to the vastus medialis. The distal fibres of MPFL were interdigitated with the deep layer of the medial retinaculum that was attached to the medial margin of the patella tendon.

CONCLUSION

These findings imply that MPFL, which was directly attached to the vastus intermedius and patella and indirectly continued to the patella tendon, could keep pulling them medially as one unit and consequently make the patella move smoothly on the trochlea during whole movement of the knee. Clinically, dysfunction of both proximal and distal MPFL fibres should be considered in the diagnosis and treatment of patella instability after traumatic patella dislocation. MPFL reconstruction with both fibres has a possibility to lead ideal function of MPFL and better instability of the patella.

Radiographic landmarks for tunnel placement in reconstruction of the medial patellofemoral ligament

PURPOSE

To verify the findings of previous studies in confirming radiographic landmarks for the femoral attachment of the medial patellofemoral ligament (MPFL), but also to define radiographic landmarks for the patellar attachment. Assess the effect of limb rotation upon these radiographic landmarks.

METHODS

The medial patellofemoral ligament was identified in ten fresh-frozen human cadaveric knees. A headed pin was used to mark the centre of the femoral and patellar attachments. True lateral radiographs were performed followed by lateral radiographs in 10° and 20° of internal and external rotation. Posterior-anterior and proximal-distal position of the headed pin was evaluated.

RESULTS

The femoral attachment averaged 3.8 ± 5.0 mm anterior to the posterior femoral cortical line and 0.9 ± 2.4 mm distal to the perpendicular line intersecting the posterior aspect of Blumensaat's line. The patellar attachment averaged 7.4 ± 3.5 mm anterior to the posterior patellar cortical line, 5.4 ± 2.6 mm distal to the perpendicular line intersecting the proximal margin of the patellar articular surface. There was a significant relationship between limb rotation and distance of femoral and patellar attachment from the posterior cortical line (P < 0.0001 and P < 0.0002 respectively).

CONCLUSION

Radiographic landmarks for the femoral attachment of the MPFL identified in this study are comparable with other recent work. This study describes new radiographic landmarks for the patellar attachment of the MPFL and highlights that it is essential to acquire true lateral radiographs if these radiographic landmarks are to be interpreted accurately.

[Patellar osteochondral injury as onset of patellar instability]

Patellar osteochondral fractures with no dislocation are uncommon and usually affect the centromedial facet of the patella. We present the case of a 10 year-old, overweight, female patient. She was seen in the emergency room after suffering an accidental fall, assessed as an osteochondral fracture-dislocation of the right patella with upper-outer displaced free fragments. By patient interview, she referred to no previous episodes of patellar dislocation. To complete the study, we performed an MRI which showed a medial facet patellar fracture, with two osteochondral fragments located in the sub-quadricipital recess, associated with other lesions suggesting patellar subluxation. We considered that the best treatment was surgery, so the following was performed: an open reduction and internal fixation with absorbable bars, lateral patellar release (Ficat technique), patellar coverage by medial portion of quadriceps (Insall technique) and internal moving of the lateral half of the patellar tendon (Goldwaith technique). The injury was checked one year later using arthroscopy. It confirmed a good reconstruction of the articular surface, and right patellar centering. At follow-up, during the physiotherapy period, the patient began to have repeated episodes of instability in the contralateral patella. The CT scan confirmed the patellar lateralisation (TAGT 17). Centering surgery was indicated due to the occurrence of multiple dislocation episodes. The patient currently carries out normal physical activity and she has a complete range of movement. Patellar osteochondral fracture is an injury frequently associated with patellar instability, which may onset in the first episode. The medial location of the lesions and the involvement of the system of medial knee stability is a fundamental finding. This fact reinforces the diagnosis of pre-fracture patellar dislocation. This is not a fracture-dislocation, but a dislocation-fracture. We may, therefore, treat the injury and its cause.

Galeazzi semitendinosus tenodesis for patellofemoral instability in skeletally immature patients

BACKGROUND

Numerous surgical treatments have been described to address subluxation or dislocation of the patella, but many are not suitable for the skeletally immature patient, as they risk injury to the proximal tibial physis or tibial tubercle apophysis. The Galeazzi semitendinosus tenodesis is a soft-tissue reconstruction technique designed to stabilize the patella without altering the femoral or the bony structures about the knee. We sought to determine if this semitendinosus tenodesis is a safe and effective treatment for patellofemoral instability in skeletally immature patients.

METHODS

We retrospectively analyzed the records of a population of skeletally immature patients who underwent semitendinosus tenodesis for patellofemoral instability at our institution from 1990 to 2006. Condition-specific outcome and function were prospectively collected, including the International Knee Documentation Committee (IKDC) score, Kujala Score, and Marx Activity Scale. Recurrent instability was defined as patient-reported postoperative subluxation, dislocation, or both.

RESULTS

Twenty-eight patients (34 total knees) were included in the study. Average follow-up was 70 months (range, 27 to 217 mo). Patients reported recurrent instability in 28 of the 34 knees (82%). Overall, 41% of patients had IKDC scores <70. Twelve knees (35%) were symptomatic enough to undergo subsequent surgery, but had similar mean IKDC (63), Kujala (81), and Marx Activity Scores (7.5) at long-term follow-up to those (IKDC 64, Kujala 79, Marx 8.2) who did not undergo additional surgeries (P=0.73, 0.88, 0.76, respectively). Complications included 1 superficial wound infection and 1 mild wound dehiscence.

CONCLUSIONS

Patellofemoral instability remains a challenging clinical problem, particularly in patients with open physes. The Galeazzi semitendinosus tenodesis is a safe procedure for patellofemoral instability in skeletally immature patients, but our long-term data suggest it may not be as successful as previously reported. Approximately 82% of patients experienced recurrent subluxation or dislocation despite surgical intervention, which may be due in large part to various predisposing factors, and there was a 35% rate of second surgeries. However, given the variability in techniques and reported results of patellofemoral stabilizing procedures in skeletally immature patients, the Galeazzi procedure may still be a reasonable way to temporize the difficult problem of patellar instability until patients reach skeletal maturity, when bony realignment procedures can be more safely used.

LEVEL OF EVIDENCE

Level IV, case series.

The operative management of patella malalignment

Management of patellofemoral joint pathology is challenging as a result of the unique and complex organization of static forces and dynamic factors contributing to its functional capacity. Anterior knee pain is a common musculoskeletal complaint seen daily in the practices of primary care physicians, rheumatologists, and orthopedic surgeons. The key to successful treatment lies not only in the correct diagnosis of a chondral defect, but more importantly, in the accurate identification of associated pathomechanical factors. Appreciating the pathoanatomic basis of the disease and addressing imbalances and anatomical abnormalities should guide treatment.Despite the complexity of the interplay of various components it is essential to attempt to describe patellar malalignement as a clinical entity in order to proceed with appropriate surgical management and successful outcomes. The goals of patellofemoral re- alignment surgery should be to create both a stable environment for optimal extensor mechanism performance and an appropriate load transmission for optimal cartilage wear and joint loading. In the context of this article we will review the operative management of patellofemoral malalignment; the indications for surgery, the different techniques available and the evidence regarding their effectiveness.A large number of procedures have been employed and they have all undergone various modifications over the course of the years. The majority of publications are retrospective series in poorly defined population groups. There are significant methodological inconsistencies and as a result there is lack of strong evidence base for the majority of these procedures.

Arthroscopic extraarticular reconstruction of the medial patellofemoral ligament with gracilis tendon autograft - surgical technique

The standard approach to reconstruct the medial patellofemoral ligament (MPFL) is by mini-open incision at its patellar insertion and femoral origin. At the medial patella rim, the MPFL insertion may be visualized in most cases by dissection during surgery. On the femur, it is more difficult to localize the MPFL remnants by a mini-open incision due to soft tissue covering the anatomical origin. Therefore, the femoral MPFL origin is usually identified by intraoperative lateral fluoroscopy. However, the insertion and origin of the MPFL at the patella and femur might be directly visualized using an arthroscopic extraarticular approach from the knee joint through a window of the synovial layer. This is especially helpful on the femoral side but also at the patella to find the individual anatomical MPFL footprints. Arthroscopic extraarticular reconstruction may then be performed using one additional medial mid-parapatellar portal. The major advantages of this technique are an individualized anatomical procedure, which is minimal invasive and cosmetically appealing. The aim of this study was to describe the arthroscopic extraarticular approach to the MPFL insertion at the patella and origin at the femur through synovial windows and to explain the procedure of arthroscopic MPFL reconstruction with a gracilis tendon autograft. Level of evidence Expert opinion, surgical technique, Level V.

Medial patella retinaculum plasty for treatment of habitual patellar dislocation in adolescents

PURPOSE

The surgical technique, medial patellar retinaculum plasty, can almost restore both static and dynamic stability and verge on anatomical repair for the treatment of habitual patellar dislocation in adolescents.

METHODS

In accordance with the injury patterns of the medial patellar retinaculum through knee MRI, we repaired different injury sites with this surgical procedure. We reviewed this technique in 16 patients with an average age of 15 years. Retrospective review of charts and radiographs immediately after the surgery up to the latest follow-up (range 12-36 months) was undertaken.

RESULTS

All patients were evaluated clinically and radiologically over an average of 20.7 months. The recovery of knee mobility results were good. No recurrence of patellar instability has been found.

CONCLUSION

We think this could be a valid technique to treat habitual patellar dislocation in adolescents.

Non-anatomic proximal realignment for recurrent patellar dislocation does not sufficiently prevent redislocation

Several operative techniques have been described for recurrent patellar dislocation. Clinical results vary depending on the procedure and indication. The present study aimed to evaluate the clinical outcome of Insall's proximal realignment for recurrent patellar dislocation at mid-term follow-up. Forty-five patients were reviewed with a mean follow-up period of 49 months after having undergone Insall's procedure. Outcome measures included reports of redislocations, complications, patient-reported outcome scores (Kujala, Tegner activity scale) and subjective assessment. No statistically significant improvements (p < 0.05) in patient-reported outcome measures were noted. Sixteen patients (35%) had poor to fair results using the Kujala score. Subjective assessment revealed that 12 patients (27%) were dissatisfied with the outcome of their surgery and would not undergo the same procedure. Ten patients (22%) had suffered from redislocation at the latest follow-up. In 4 cases (9%), intra-articular knee hematoma occurred which required arthroscopic intervention. The overall mid-term outcome of the present study shows low patient satisfaction. Non-anatomic realignment for recurrent patellar dislocation does not adequately prevent redislocation.

Recession wedge trochleoplasty as an additional procedure in the surgical treatment of patellar instability with major trochlear dysplasia: early results

INTRODUCTION

The importance of a dysplastic trochlea as a component of patellar instability has long been recognized. An original trochleoplasty technique consisting in retro-trochlear recession wedge osteotomy was described by Goutallier et al. The aim is not to fashion a groove but to reduce the bump without modifying patellofemoral congruence.

PATIENTS AND METHODS

This retrospective study reports the operative technique and short-term outcomes of a consecutive case series of 17 patients (19 knees) who underwent recession wedge trochleoplasty for patellofemoral instability associated with severe trochlear dysplasia. Other contributing factors of patellar instability were also corrected as part of the surgical procedure: tibial tuberosity transfer (n=18), MPFL reconstruction (n=8).

RESULTS

Minimum follow-up was 12 months (mean, 34 months; range, 12 to 71 months). The trochlear prominence was reduced from a mean 4.8mm (range, 0 to 8mm) to -0.8mm (range, -8 to 6mm). Patellar tilt was reduced from a mean 14° (range, 6° to 26°) to 6° (range, -1° to 24°). Two cases showed recurrent patellofemoral instability. Mean Kujala, KOOS and IKDC score were respectively 80 (± 17), 70 (± 18) and 67 (± 17) at last follow-up. Three patients required further operations, apart from removal of metal screws: arthroscopic arthrolysis for stiffness (n=1), revision for tibial tuberosity non-union (n=1), and supratrochlear exostosectomy (n=1).

DISCUSSION

Recession wedge trochleoplasty is a feasible additional procedure addressing bony trochlear abnormality in the surgical treatment of patellar instability. Our attitude is to perform it never in isolation but associated to realignment of the extensor apparatus according to the à la carte surgery concept. It seems to be effective in preventing future patellar dislocation and reducing anterior knee pain in case of painful patellofemoral instability with a major dysplastic trochlea, or in revision cases when other realignment procedures have failed.

In vivo positioning analysis of medial patellofemoral ligament reconstruction

BACKGROUND

Several techniques have been described for reconstruction of the medial patellofemoral ligament (MPFL). The anatomical insertion of the MPFL has been defined; however, there are no reports describing the accuracy of femoral graft positioning assessed postoperatively.

PURPOSE

To analyze our femoral tunnel positioning for MPFL reconstruction in correlation with our clinical results.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The authors reported a prospective series of 29 MPFL reconstructions with a minimum follow-up of 24 months. The tunnel positioning analysis was performed using plain radiographs and magnetic resonance imaging at 1-year follow-up.

RESULTS

Twenty-nine femoral tunnels were analyzed; 20 femoral tunnels (69%) were considered to be in good position on plain radiographs. On magnetic resonance imaging, the authors found 19 femoral tunnels (65%) in a proper location, 5 (17.5%) in a high position, and 5 in an anterior and/or high position.

CONCLUSION

The study highlights the difficulty of reproducible MPFL reconstruction. The surgical procedure continues to be improved and finding a reliable technique to anatomically place the graft remains challenging. Verifying femoral tunnel placement radiographically may be recommended during surgery.

The relation of the femoral physis and the medial patellofemoral ligament

PURPOSE

The purpose of this study was to determine the origin of the medial patellofemoral ligament (MPFL) relative to the distal femoral physis by use of an indirect radiologic method.

METHODS

Twenty radiographs from adolescent male and female subjects (10 samples from each group) were used. The subjects studied were all skeletally immature, with an open distal femoral physis. The radiographic technique described by Schöttle et al. was used to identify the origin of the MPFL. Imaging software was used to determine the approximate distance of the MPFL origin relative to the open growth plate of the subjects involved.

RESULTS

In all 20 radiographs the medial physis was found to be distal to the average MPFL insertion point. The mean location for the female physis was 2.7 +/- 1.1 mm distal to the MPFL origin. The mean location for the male physis was 4.6 +/- 2.4 mm distal to the MPFL origin.

CONCLUSIONS

Based on an indirect radiographic technique, we found that the origin of the MPFL is just proximal to the femoral physis.

CLINICAL RELEVANCE

This information may be useful when planning medial retinacular surgical procedures in skeletally immature athletes to help avoid clinically significant physeal injury.

Anatomical confirmation of the use of radiographic landmarks in medial patellofemoral ligament reconstruction

BACKGROUND

A recent study has described radiographic landmarks for femoral insertion of the medial patellofemoral ligament. Clinical relevance and application of these landmarks for surgical reconstruction have yet to be determined.

HYPOTHESIS

Radiographic landmarks can be used to accurately determine the femoral insertion of the medial patellofemoral ligament in a percutaneous fluoroscopically guided surgical technique.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The femoral insertion of the medial patellofemoral ligament was estimated using fluoroscopy in 8 fresh-frozen human cadaveric knees. The knees were dissected and the true anatomical medial patellofemoral ligament femoral insertion was identified. Radiographic markers were placed on both the estimated and anatomical medial patellofemoral ligament and a repeat lateral radiograph was performed. Using imaging software, the distance between the true anatomical insertion and the fluoroscopically determined insertion was calculated. Results All 8 points determined by fluoroscopically guided pin placement averaged less than 4 mm from the anatomical insertion. The radiographic landmark method consistently placed the origin on average 2.5 mm anterior and 0.6 mm distal to the anatomical insertion.

CONCLUSION

Radiographic landmarks determined by fluoroscopy can be used to accurately reproduce the femoral insertion of the medial patellofemoral ligament in ligament reconstruction.

CLINICAL RELEVANCE

Confirming the use of radiographic landmarks to determine the medial patellofemoral ligament femoral insertion may help to increase accuracy and precision in ligament reconstruction and minimize surgical dissection.

Reconstruction of the medial patellofemoral ligament using a longitudinal patellar tunnel technique

Patellar instability is a common clinical problem affecting a young, active population. A large number of procedures have been described to treat patellar instability. We present the clinical results in a case series of 25 medial patellofemoral ligament reconstructions in 21 patients with up to 30 months follow-up (mean: 7.3). Reconstruction was performed using either the gracilis or semitendinosus tendon autograft. The Tegner activity score improved overall from 3 to 4.4 at follow-up and the mean follow-up Kujala score was 87 (range: 55-100). No patella redislocations were observed. Five patients (20%) required a manipulation under anaesthetic but subsequently regained a satisfactory range of motion. Medial patellofemoral reconstruction with both gracilis and semitendinosus tendon graft using a longitudinal tunnel technique provided good post-operative stability restoring the primary soft tissue restraint to pathological lateral patellar displacement with no complications of post-operative patellar fracture.