Medial patellofemoral ligament reconstruction in patellar instability

Medial patellofemoral ligament reconstruction using an endobutton device: A narrative review

Since the recognition of MPFL as the primary soft-tissue restraint to lateral displacement of the patella, its reconstruction gained popularity either alone or in combination with other procedures. Today, although there are plenty of techniques described in the literature, there is no consensus regarding which one is better. MPFL reconstruction using an endobutton device has been proved to be a reliable option with satisfying clinical results. Single or dual tunnel can be done depending on surgeon's preference. For safer outcomes more randomized controlled trials should be done while authors should be more meticulous when it comes to surgical technique.

Medial patellofemoral ligament reconstruction using patella bone tunnel techniques with or without implants. A systematic review of outcomes and complications

PURPOSE

Τhe main goal of this study was to compare the clinical results, including the complication rates and patient-reported outcomes, in patients who underwent surgery for recurrent patellar dislocation using different patellar tunnel fixation techniques. This study compared Medial Patellofemoral Ligament (MPFL) reconstruction implant free techniques against ones that used implants.

METHODS

The present systematic review was conducted according to the PRISMA guidelines. The literature search was conducted in January 2023. We included patients who underwent isolated MPFL reconstruction for recurrent patellar instability. Patients with confirmed concomitant or prior ipsilateral knee procedures, multiligament injury, severe patellar dysplasia or less than 6 months of follow-up were excluded. MINORS and MCMS scores were used for the assessment of methodological quality.

RESULTS

Data from 750 procedures were collected, of which 284 used implants to perform the procedure while in 455 an implant-free technique was used. Patient age at the time of surgery ranged from 11 to 60 years while the follow-up time of the studies ranged between 3 and 108 months. Postoperative Kujala (0.3, p = 0.89) and Lysholm (1.2, p = 0.26) scores were better in the implant-free techniques compared to implant-based. A higher rate of recurrent dislocation (OR 0.51; 95% CI 0.10-2.54, p = 0.4), subluxation (OR 0.20; 95% CI 0.40-0.88, p = 0.019) and stiffness (OR 0.76; 95% CI 0.33-1.72, p = 0.55) was noted in the implant-free techniques, while the implant-based techniques displayed increased incidence of patella fractures (OR 3.12; 95% CI 0.77-12.6, p = 0.09), reoperation (OR 1.69; 95% CI 0.78-3.65, p = 0.17) and infection (OR 2.07; 95% CI 0.46-9.32, p = 0.33).

CONCLUSION

There was no significant difference between the 2 techniques in terms of patient reported outcomes. Regarding complications, MPFL reconstruction using implants demonstrated significant higher rate of patella fractures while the implant free technique showed a greater risk of subluxation.

Isolated medial patellofemoral reconstruction outcomes: A systematic review and meta-analysis

BACKGROUND

Treatment of patellar instability remains up for debate, and a combination of tibial tubercle osteotomy and medial patellofemoral ligament reconstruction (MPFLr) of the medial patellofemoral ligament (MPFL) has become the mainstay treatment for recurrent lateral patellar dislocation. Due to limited small studies, there remains a variety of surgical techniques still being practiced. The use of MPFL reconstruction, in isolation, has demonstrated promise.

PURPOSE

The purpose of this systematic review and meta-analysis is to investigate if isolated medial patellofemoral ligament reconstruction (iMPFLr) can safely and efficaciously restore knee stability and to present the patient demographics, surgical techniques, graft choices, clinical outcomes, and complications after iMPFLr for recurrent patellar dislocation (RPD).

METHODS

A review of the current literature according to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, yielded 299 abstracts. Twenty-seven articles met the inclusion/exclusion criteria accounting for 1200 patients. Data was pooled and analyzed focusing on patient demographics, graft type used, Kujala, International Knee Documentation Committee (IKDC), Lysholm, Tegner, and complications.

RESULTS

Across all studies the weighted mean age was found to be an average of 24.5 years, BMI was 24.9 kg/m2, follow-up was 47.3 months, as 67% were female, TT-TG distance was 15.3 mm, and Caton Deschamps index 1.11. The pooled effect size difference of pre versus post assessment of Kujala was -2.8, IKDC was -4.5, Lysholm was -6.4, and Tegner was -0.74. The pooled complication rate was found to be 8% across all included studies. A subgroup analysis was also performed, specifically looking at how single bundle, double bundle, gracilis, semitendinosus and knee angle during fixation effect outcome data.

CONCLUSION

This systematic review and meta-analysis demonstrates that isolated MPFL reconstruction is a safe and effective treatment for recurrent patellar dislocations. Given the efficacy of isolated MPFL reconstruction, future investigations should aim to uncover the exact TT-TG distance, trochlear dysplasia, and patella alta grade for selecting patients to undergo this procedure. Furthermore, more primary research needs to be conducted on this topic due to the overall lack of published data from randomized controlled studies and no broad standardization of outcome measurements.

LEVEL OF EVIDENCE

(4) Systematic Review and Meta-Analysis.

Does medial patellofemoral ligament reconstruction result in femoral tunnel enlargement? A systematic review

BACKGROUND

Medial patellofemoral ligament (MPFL) reconstruction is a common surgical procedure for treating patellar instability. The primary aim of this systematic review was to determine whether MPFL reconstruction (MPFLR) leads to femoral tunnel enlargement (FTE). The secondary aims were to explore the clinical effects and risk factors of FTE. Electronic databases (MEDLINE, Global Health, Embase), currently registered studies, conference proceedings and the reference lists of included studies were searched independently by three reviewers. There were no constraints based on language or publication status. Study quality assessment was conducted. 3824 records were screened in the initial search. Seven studies satisfied the inclusion criteria, evaluating 380 knees in 365 patients. Rates of FTE following MPFLR ranged from 38.7 to 77.1%. Five low quality studies reported FTE did not lead to detrimental clinical outcomes as assessed with the Tegner, Kujala, IKDC, and Lysholm scores. There is conflicting evidence regarding change in femoral tunnel width over time. Three studies (of which two had a high risk of bias) reported age, BMI, presence of trochlear dysplasia and tibial tubercle-tibial groove distance did not differ between patients with and without FTE, suggesting these are not risk factors for FTE.

CONCLUSION

FTE is a common postoperative event following MPFLR. It does not predispose poor clinical outcomes. Current evidence lacks the ability to identify its risk factors. The reliability of any conclusions drawn is hindered by the low level of evidence of the studies included in this review. Larger prospective studies with long-term follow up are required to reliably ascertain the clinical effects of FTE.

Prognostic factors for isolated medial patellofemoral ligament reconstruction: A systematic review

BACKGROUND

Evidence concerning the influence gender, age, and the time elapsed from the first dislocation to surgery in the outcomes of Medial Patella Femoral Ligament (MPFL) reconstruction are lacking. This systematic review was conducted to investigate whether patient characteristics have an influence in the clinical outcomes of MPFL reconstruction for patients with patellofemoral instability.

MATERIAL AND METHODS

This study followed the PRISMA guidelines. The main databases were accessed in February 2021. All the studies reporting outcomes of primary MPFL reconstruction in patients with recurrent patellofemoral instability were considered for inclusion. A multivariate analysis diagnostic tool was used to analyse the association between age, gender and time from injury to surgery and the surgical outcomes at last follow-up.

RESULTS

A total of 50 articles (2037 procedures) were included. The mean follow-up was 40.90 ± 24.8 months. The mean age was 23.6 ± 3.9 years. 64.3% (1309 of 2037 patients) were female. The mean time from injury to surgery was 64.5 ± 48.9 months. Women showed no statistically significant association with the Kujala score or complications. Older patients had a reduced risk to incur re-dislocations (P = 0.01) and revisions (P = 0.01). Longer time from injury to surgery was associated with greater risk to incur re-dislocations (P = 0.01), and with lower Kujala score (P < 0.0001). No other statistically significant association was evidenced.

CONCLUSION

The time span from the first patellar dislocation to the surgical reconstruction was a negative prognostic factor, while sex had no influence on surgical outcomes. The role of patients age on surgical outcomes remains unclear.

Isolated medial patellofemoral ligament reconstruction for recurrent patellofemoral instability: analysis of outcomes and risk factors

Background

The medial patellofemoral ligament (MPFL) is always damaged after patellar dislocation. In selected patients, MPFL reconstruction is necessary to restore a correct patellar tracking. Despite the large number of different techniques reported to reconstruct the MPFL, there is no consensus concerning the optimal procedure, and debates is still ongoing. The present study analysed the results after isolated MPFL reconstruction in patients with patellofemoral instability. Furthermore, a subgroup analysis of patients presenting pathoanatomical risk factors was made.

Methods

In November 2020, the main electronic databases were accessed. All articles reporting the results of primary isolated MPFL reconstruction for recurrent patellofemoral instability were considered for inclusion. Only articles reporting a minimum 12-month follow-up were eligible.

Results

Data from a total of 1777 knees were collected. The mean age of the patients involved was 22.8 ± 3.4 years. The mean follow-up was 40.7 ± 25.8 months. Overall, the range of motion (+ 27.74; P < 0.0001) and all the other scores of interests improved at last follow-up: Kujala (+ 12.76; P = 0.0003), Lysholm (+ 15.69; P < 0.0001), Tegner score (+ 2.86; P = 0.006). Seventy-three of 1780 patients (4.1%) showed a positive apprehension test. Thirty of 1765 patients (1.7%) experienced re-dislocations, while 56 of 1778 patients (3.2%) showed persisting joint instability. Twenty-five of 1786 patients (1.4%) underwent revision surgeries.

Conclusion

Isolated MPFL reconstruction for recurrent patellofemoral instability provides reliable surgical outcomes. Patients with pathoanatomical predisposing factors reported worse surgical outcomes.

Lateral retinacular release combined with MPFL reconstruction for patellofemoral instability: a systematic review

INTRODUCTION

The role of the lateral retinaculum in patellofemoral instability is still debated. Lateral retinacular release (LRR), has been extensively performed in combination with different surgical procedures, including reconstruction of medio-patellofemoral ligament (MPFL). Despite controversial indications, the results from these studies seem promising. The present study conducts a systematic review about current biomechanical and clinical evidence concerning the role of LRR in combination with MPFL reconstruction. We performed a comprehensive literature research, comparing the outcomes of MPFL reconstruction with and without LRR.

MATERIALS AND METHODS

This systematic review was conducted according to the PRISMA guidelines. The literature search was performed in August 2020. All articles describing the outcome of isolated MPFL reconstruction alone or in combination with a LRR in patients with recurrent patellofemoral instability were considered for inclusion. Only articles reporting data on patients with a minimum of 12-month follow-up were included. Only articles reporting quantitative data under the outcomes of interest were included.

RESULTS

A total of 63 articles were eligible for this systematic review, including 2131 knees. The mean follow-up was 40.87 ± 24.1 months. All scores of interests improved in favour of the combined group: Kujala + 3.8% (P = 0.01), Lysholm + 4.2% (P = 0.004), Tegner + 0.8 points (P = 0.04), IKDC + 9.8% (P = 0.02). The ROM was comparable between the two groups (P = 0.4). Similarity was found in terms of positivity to the apprehension test (P = 0.05), rate of complications (P = 0.1), re-dislocations (P = 0.8), and revision surgeries (P = 0.1).

CONCLUSION

There is no evidence that adding a lateral release impacts positively on the outcome of MPFL reconstruction.

LEVEL OF EVIDENCE

IV, Systematic review.

Isolated versus combined medial patellofemoral ligament reconstruction for lateral instability of the patella

INTRODUCTION

Medial patellofemoral ligament reconstruction (MPFLR) is regularly combined with a tibial tuberosity transfer (TTT) in cases of recurrent patellar instability with underlying structural deformity. However, these indications for a TTT have recently come into question. This study aimed to assess the traditional indications by comparing the outcomes of isolated and combined MPFLR for the treatment of recurrent lateral patellar dislocation.

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included studies were those which reported the outcomes of either isolated or combined or both MPFLR. Studies were required to report at least one of the following: redislocation rate, revision due to instability, or the Kujala score.

RESULTS

We found no difference between isolated and combined MPFLR in terms of redislocation ( p = 0.48), revisions due to instability ( p = 0.36), positive apprehension tests ( p = 0.25), or the Kujala score ( p = 0.58). Combined reconstruction presented more complications compared to isolated procedures ( p = 0.05). Subgroup analysis revealed no significant difference between studies investigating isolated medial patellofemoral ligament reconstruction MPFLR performed in patients with normal tibial tuberosity-trochlear groove (TT-TG) distances only or in patients with both normal and elevated TT-TG distances.

CONCLUSIONS

According to the published data, there is no difference in outcomes between isolated and combined MPFLR. Underlying structural deformity did not demonstrate any significant effect on the success of the isolated MPFLR. Although there are definite indications for combined reconstruction, the current evidence suggests that our inclusion criteria may not be entirely correct. Further study is required to clarify and refine the true indications for combined MPFLR.

LEVEL OF EVIDENCE

III, meta-analysis of nonrandomized studies.

Graft choice for isolated MPFL reconstruction: gracilis versus semitendinosus

INTRODUCTION

After the first patellar dislocation, most patients report damage of the medio-patellofemoral ligament (MPFL) and surgical reconstruction is required. The purpose of this study is to systematically review current evidence and to clarify the role of the gracilis and semitendinosus tendons as graft for isolated MPFL reconstruction.

MATERIALS AND METHODS

The present systematic review was conducted according to the PRISMA guidelines. The literature search was conducted in October 2019. All clinical trials using the semitendinosus and/or gracilis tendon grafts for isolated MPFL reconstruction in patients with patellofemoral instability were considered for inclusion. Only articles reporting a minimum of 12-month follow-up were considered. The PEDro score was used for the methodological quality assessment.

RESULTS

Data from 1491 procedures were collected. The mean follow-up was 36.12 months. There was comparability among the patient baseline. All the scores of interests (Kujala, Tegner, Lysholm) and range of motion scored better in the semitendinosus group. Moreover, in favour of the semitendinosus group, a statistically significant reduction of the revision surgeries and re-dislocations were evidenced. Apprehension test and persistent instability sensation found any statistical correlations.

CONCLUSION

Isolated MPFL reconstruction through semitendinosus tendon graft performed better than the gracilis in selected patients suffering from recurrent patellofemoral instability.

Single- versus double-bundle patellar graft insertion for isolated MPFL reconstruction in patients with patellofemoral instability: a systematic review of the literature

INTRODUCTION

The MPFL reconstruction is performed either via a single-bundle (SB) or double-bundle (DB) procedure. The purpose of this study is to perform a systematic review comparing SB versus DB graft for recurrent patellofemoral instability, to summarize current evidence, and to clarify the role of both techniques. We focused on clinical scores, physical examination, complications, revision surgeries, and failures.

MATERIAL AND METHODS

In May of 2019 the main online databases were accessed. All the clinical studies treating isolated MPFL reconstruction for patellofemoral instability through a single and/or double-bundle graft were enrolled in the present systematic review. Only articles reporting primary isolated MPFL reconstruction, reporting a minimum of 12-months follow-up were considered for inclusion.

RESULTS

The scores of interest were in favour of the DB cohort: Kujala (+ 3.2, P = 0.03), Lysholm (+ 5.1, P = 0.001), Tegner (+ 0.3, P = 0.2), IKDC (+ 5.4, P = 0.01), VAS (+ 0.8, P = 0.3), ROM (+ 9.96, P = 0.04). In the DB graft, a reduction of overall complications (OR 0.59; P = 0.1), further surgeries (OR 0.64; P = 0.12) and re-dislocations (OR 0.61; P = 0.16) was observed. The SB group reported a reduction in the post-operative apprehension test (OR 2.42; P = 0.24).

CONCLUSION

Current study support the use of double-bundle tendon graft for isolated MPFL reconstruction in selected patients with recurrent patellofemoral instability.

Patellar fixation graft via suture anchors versus tunnel techniques during isolated MPFL reconstruction for recurrent patellofemoral instability: a systematic review of the literature

INTRODUCTION

There is still a lack of evidence concerning the patellar fixation of the medial patellofemoral ligament (MPFL) graft in selected patient with recurrent instability. The purpose of the present study was to investigate and compare clinical outcomes and further complications of isolated MPFL reconstruction via suture anchors versus tunnel techniques for recurrent patellofemoral instability.

MATERIALS AND METHODS

This systematic review of the literature was conducted according to the PRISMA guidelines. In September 2019, the main databases were accessed. All the clinical trials performing isolated MPFL reconstruction in patients with recurrent patellofemoral instability were included in the present study. Only articles fixing the MPFL graft through suture anchors and/ or patellar tunnel techniques were included in the analysis.

RESULTS

Data from 46 papers (1712 patients) were recorded. The mean follow-up was 40 ± 18 months. No differences were found in Kujala, Lysholm and Tegner score, International Knee Documentation Committee, visual analogic scale, range of motion and re-dislocation rate. The suture anchors fixation group detected reduced rate of apprehension test (OR: 0.6; p = 0.03), revision surgeries (OR: 0.4; p = 0.02) and anterior knee pain (OR: 0.05; p < 0.0001) and reduced not-classified complications (OR: 0.18; p < 0.0001).

CONCLUSION

Both the suture anchors and the bone-tunnels are a feasible option for isolated MPFL reconstruction in patients with recurrent patellofemoral instability. Patellar fixation via suture anchors evidenced a reduced rate of anterior knee pain, revision surgeries, apprehension test and an overall reduced complication compared to the bone-tunnel technique.

Extensive Lateral Release and Medial Patellofemoral Ligament Reconstruction in 25 Years of Chronic Fixed Lateral Patellar Dislocation: A 5-Year Follow-Up Case Report

Lateral dislocation of the patella is not uncommon and may impede daily activities as this causes compressive dysfunction and instabilities. Most cases of patellar lateral dislocation are due to damage to the medial patellofemoral ligament (MPFL), either rupture of detachment of the patella or femoral attachment. MPFL reconstruction alone was considered adequate for the treatment of this condition. We present a case of a 49-year-old male with chronic posttraumatic lateral patellar dislocation of the right knee of 25 years, which we treated with extensive lateral release and right medial patellofemoral ligament reconstruction with 5-year follow-up data.

Systematic Review of Medial Patellofemoral Ligament Reconstruction Techniques: Comparison of Patellar Bone Socket and Cortical Surface Fixation Techniques

PURPOSE

To compare patellar bone socket and cortical surface fixation techniques for isolated medial patellofemoral ligament (MPFL) reconstruction and determine whether there was a difference in (1) complication rates, including fracture of the patella; (2) redislocation rates; or (3) patient-reported outcomes.

METHODS

A literature search was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included patients who underwent isolated MPFL reconstruction for recurrent patellar instability. Patients with confirmed concomitant or prior ipsilateral knee procedures, multiligament injury, or less than 3 months of follow-up were excluded. Risk-of-bias assessment was performed using the Methodological Index for Non-randomized Studies (MINORS) system. Studies were classified by surgical technique (patellar bone socket group [group S] vs cortical fixation group [group F]), and complications, redislocations, and patient-reported outcomes were collected.

RESULTS

A total of 29 studies yielded 981 patients with MPFL reconstruction for inclusion. Of the patients, 620 underwent a patellar bone socket technique and 361 underwent a cortical fixation technique. Patients ranged in age from 11 to 68 years. Patellar fracture rates ranged from 0% to 17% in group S and were 0% in all group F studies. Mean Kujala scores ranged from 83.5 to 93.6 in group S and from 84.4 to 94.5 in group F. Mean Lysholm scores ranged from 84.6 to 91.7 in group S and from 83.5 to 95 in group F. Redislocation rates ranged from 0% to 21% in group S and from 0% to 13% in group F. Although heterogeneous in nature, complication rates ranged from 0% to 28% in group S and from 0% to 4% in group F.

CONCLUSIONS

MPFL reconstruction techniques with patellar bone sockets showed a larger range of complication rates than cortical fixation techniques, although overall, complications remained uncommon. Clinically, the bone socket group had comparable postoperative redislocation rates and patient outcomes to the group treated with cortical fixation techniques.

LEVEL OF EVIDENCE

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

Single- and double-bundle medial patellofemoral ligament reconstruction procedures result in similar recurrent dislocation rates and improvements in knee function: a systematic review

PURPOSE

To evaluate medial patellofemoral ligament (MPFL) reconstruction using hamstring tendon autografts using single-bundle (SB) and double-bundle (DB) techniques, and compare the clinical outcomes including the Kujala score, postoperative apprehension, recurrent subluxation or dislocation, and complications.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched for relevant literature using the terms ''medial patellofemoral ligament'' and ''MPFL''. The pooled mean values of improvement in the Kujala score were calculated by random effects meta-analysis. Unweighted estimates for the rates of postoperative apprehension, recurrent subluxation or dislocation, and complications were determined by dividing the total number of occurrences by the total number of knees.

RESULTS

Thirty-one articles were included, involving 1063 patients (1116 knees). Two hundred and forty-four patients (254 knees) underwent SB reconstruction, while 819 patients (862 knees) underwent DB reconstruction. The pooled mean values of Kujala score improvement were similar in the SB group (30.1; 95% CI 26.6-33.6) and DB group (30.7; 95% CI 27.7-33.7). The SB group had a significantly greater rate of postoperative apprehension (7.9%) than the DB group (4.1%; P = 0.014). There were no significant differences between the two groups in the rates of recurrent subluxation or dislocation (1.2 and 1.6%) and complications (10.6 and 7.7%).

CONCLUSION

With variability in patient populations and surgical techniques, the DB procedure for isolated MPFL reconstruction demonstrates similar outcomes to the SB technique regarding improvement of knee function, recurrent subluxation or dislocation, and complications. The SB technique may have a greater risk of postoperative apprehension, whereas the DB technique may cause more stiffness.

LEVEL OF EVIDENCE

IV.

Graft Choice in Isolated Medial Patellofemoral Ligament Reconstruction: A Systematic Review With Meta-analysis of Rates of Recurrent Instability and Patient-Reported Outcomes for Autograft, Allograft, and Synthetic Options

PURPOSE

To determine whether graft selection or patient age affects the following after isolated medial patellofemoral ligament (MPFL) reconstruction: (1) rates of recurrent instability, (2) rates of postoperative complications (other than instability), and (3) subjective symptom improvement.

METHODS

A systematic search identified studies reporting outcomes for isolated MPFL reconstruction. Rates of recurrent instability, subjective Kujala knee function scores, and complications were tabulated. Symptom improvement was defined as change in Kujala score (preoperative evaluation to final follow-up).

RESULTS

Forty-five studies were included with 27 documented cases of recurrent instability among 1,504 patients (1.8%); instability rates ranged from 0% to 20.0% overall; among autograft in adults, 0% to 11.1% (1.4%, 18/1,260); among autograft in adolescents, 0% to 20% (10.0%, 8/80); among allograft, 0% (0/65 cases); and among synthetic, 0% to 3.3% (1.3%, 1/76). Among autograft choices in adults, rates of recurrent instability were low; recurrence with gracilis ranged from 0% to 11.1% (0.9%, 1/116); with semitendinosus, 0% to 6.3% (0.6%, 4/676); with quad or patellar tendon, 0% (0/65); and with adductor tendon, 5.6% to 8.3% (6.7%, 2/30). Complication rates ranged from 0% to 34.4%. All included studies reported significant improvement in Kujala scores after surgery (P < .01). There was significant heterogeneity in effect size and evidence of reporting bias among small studies, precluding reliable pooled analysis of treatment effect.

CONCLUSIONS

Autograft is not superior to allograft or synthetic grafts for isolated reconstruction of the MPFL, and rates of recurrent instability are generally low. Isolated MPFL reconstruction can provide significant symptom relief regardless of graft selection, although there is a bias toward reporting better than expected results among smaller studies. Pediatric patients and patients treated with adductor tendon autograft have higher recurrent instability rates. While caution should be used in making definitive recommendations secondary to the small number of allograft and synthetic studies, selection of graft type based on surgeon preference, comfort, and prior experience remains appropriate.

LEVEL OF EVIDENCE

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

Case report of a ruptured endobutton used in medial patellofemoral ligament reconstruction causing patellofemoral impingement

The medial patellofemoral ligament (MPFL) is a key soft tissue stabilizer of the medial patella, with deficiency proven to be a key contributor to patellar dislocation. Reconstruction of this ligament has become a widely employed procedure in managing patients with recurrent patellar dislocation, and is also gaining popularity in the setting of primary dislocation. A wide variety of techniques have been described, differing in the type of graft used, sites for fixation and fixation technique. A number of complications have also been reported in the literature, including post-operative stiffness, apprehension, patellar fracture and recurrence of instability and dislocation. Here we report a case of an endobutton used in MPFL reconstruction becoming displaced after minimal trauma in a young female patient, subsequently causing patellofemoral irritation, patellar cartilaginous damage and functional limitation. This complication has not been previously reported to our knowledge and is one that surgeons must be aware of.

Surgical treatment of patellar instability: clinical and radiological outcome after medial patellofemoral ligament reconstruction and tibial tuberosity medialisation

INTRODUCTION

The aim of this retrospective study was to analyse clinical and radiological outcome after medial patellofemoral ligament reconstruction (MPFLR) and tibial tuberosity medialisation (TTM) in patients with recurrent patellar instability.

MATERIALS AND METHODS

Thirty-five patients were included between 2008 and 2012. According to defined criteria such as tibial tuberosity-trochlear groove (TTTG) distance, hyperpression on the lateral patella facet and lateral retropatellar cartilage damage either MPFLR (group A) or TTM (group B) was performed: 18 patients underwent TTM, the other 17 patients underwent MPFLR. At a mean of 25.4 ± 9.7 (group A) and 35.2 ± 17.6 months (group B) patients were clinically and radiologically reviewed. Validated knee scores such as Kujala, Lysholm and Tegner score were evaluated.

RESULTS

In both groups one patient reported of a non-traumatic patellar redislocation. Patients who underwent MPFLR (group A) had less pain postoperatively during activity according to the Visual Analogue Scale (group A: 2.0 ± 2.1 points, group B: 3.9 ± 2.3 points). Retropatellar cartilage damage increased in group B from grade 1 (range: 1-3) preoperatively to grade 2 (range 1-3) postoperatively (p > 0.05). All other clinically evaluated items, as well as the applied knee scoring systems, indicated no significant difference (p > 0.05) and displayed good to excellent results.

CONCLUSIONS

MPFLR and TTM leed to good clinical results despite its own indications. For this reason-in selected cases-TTM may still be a suitable procedure for surgical treatment of patellar instability. However, patients treated by TTM (group B) revealed an increased retropatellar cartilage damage as well as significantly more pain during activity.

Isolated reconstruction of the medial patellofemoral ligament with autologous quadriceps tendon

Background

Since the role of the medial patellofemoral ligament (MPFL) as the primary soft-tissue restraint against lateral patellar translation has been recognized, several different reconstruction procedures for the treatment of patellar instability have been proposed over recent years. Many of these techniques require bony procedures and hardware fixation at the patellar and femoral side, leading to complications as described previously in the literature. The purpose of the present study is to describe the technique of isolated MPFL reconstruction using the quadriceps tendon and report the results at a mean follow-up of 38 months. The hypothesis is that this technique, not requiring drilling of bone tunnels on the patellar and femoral side, may be a "simple and safe" mean to manage patellar instability, giving good clinical results with low complication rate in selected patients with normal osseous anatomy.

Materials and methods

Sixteen consecutive patients (9 male, 7 female; mean age 22 years) with chronic patellar instability underwent medial patellofemoral reconstruction with the superficial layer of the quadriceps tendon. All the patients were evaluated preoperatively and postoperatively by physical examination and subjectively with Kujala and Lysholm scores.

Results

The average follow-up was 38 months (range 28–48 months). No recurrent episodes of dislocation or subluxation and no complications occurred. The mean Kujala score increased from 35.8 preoperatively to 88.8 postoperatively and the Lysholm score improved from 43.3 preoperatively to 89.3 postoperatively.

Conclusions

Isolated MPFL reconstruction using an autologous quadriceps tendon and not requiring bone tunnels, may be a safe, simple and effective procedure for the treatment of patellar instability without complications such as patellar fracture as reported by clinical studies using hamstring grafts. For the same reason it may also be indicated in skeletally immature patients.

Level of evidence

Level IV.