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Graft and fixation variations in medial patellofemoral ligament reconstruction: A prospective comparative analysis
⁎Corresponding author: Arnab Karmakar. arnab.doctor@gmail.com
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Received: ,
Accepted: ,
This article was originally published by Reed Elsevier India Pvt. Ltd. and was migrated to Scientific Scholar after the change of Publisher.
Abstract
Abstract
To prospectively compare clinical and functional outcomes of three commonly used medial patellofemoral ligament (MPFL) reconstruction techniques: hamstring autograft with patellar suture anchor fixation, hamstring autograft with implant-less patellar fixation, and quadriceps tendon autograft.
In this prospective comparative study, 30 patients with recurrent patellar instability underwent MPFL reconstruction and were equally allocated into three groups: Group 1, semitendinosus or gracilis autograft with patellar suture anchor fixation and femoral interference screw fixation; Group 2, semitendinosus or gracilis autograft with implant-less patellar fixation and femoral screw fixation; and Group 3, quadriceps tendon autograft with femoral screw fixation. Femoral tunnel placement was anatomically guided at Schöttle's point. Functional outcomes were assessed preoperatively and at 3, 6, and 12 months using Kujala, Lysholm, and Tegner scores. Patient satisfaction and return-to-sports time were evaluated as secondary outcomes.
All three groups demonstrated significant improvement in Kujala, Lysholm, and Tegner scores over time (p < 0.001). However, no statistically significant differences were observed between the groups at any follow-up point. Secondary outcomes, including patient satisfaction and time to return to sports, were also comparable across groups at 12 months.
This study shows that All three MPFL reconstruction techniques provide comparable clinical outcomes. All groups demonstrated significant functional improvement at 12 months, with no differences in functional scores, patient satisfaction, or return-to-sport timelines. These findings suggest that, when anatomical principles are respected, surgeons may choose the technique best suited to patient factors and surgical expertise without compromising outcomes.
1 Introduction
1.1 Background/rationale
Lateral patellar instability is a common orthopedic challenge, particularly in adolescents and young adults, often resulting from traumatic dislocations or underlying anatomical predispositions. Recurrent dislocations can lead to pain, functional limitations, and long-term patellofemoral joint degeneration if not adequately addressed. The medial patellofemoral ligament (MPFL) is recognized as the primary soft tissue restraint against lateral patellar displacement, contributing up to 60% of the medial stabilizing force in early knee flexion.1 Consequently, reconstruction of the MPFL has become a cornerstone in the surgical management of recurrent lateral patellar instability. Various techniques for MPFL reconstruction have been described, differing mainly in graft selection and fixation strategies. Commonly used autografts include the semitendinosus, gracilis, or quadriceps tendon, while fixation methods at the patella range from suture anchors and screws to implant less techniques.2–4 Although each technique demonstrates favorable outcomes, there is a paucity of prospective comparative data evaluating their relative efficacy, functional recovery, and complication rates. The choice of graft and fixation can influence surgical complexity, rehabilitation, and early postoperative outcomes.5,6 Understanding these differences is critical to optimizing patient care, guiding surgical decision-making, and improving functional recovery.
1.2 Objective
This study aims to prospectively compare three techniques of MPFL reconstruction, semitendinosus/gracilis graft with suture anchor fixation, semitendinosus/gracilis graft with implant less patellar fixation, and quadriceps tendon graft with screw fixation, in terms of clinical outcomes, functional scores, and patient-reported satisfaction over a 12-month follow-up period.
2 Methods
2.1 Study design
This was a descriptive comparative study with prospective design, conducted at tertiary orthopaedic centre in Kolkata between January 2023 and January 2024. The study was designed to evaluate and compare the clinical and functional outcomes of three different surgical techniques for medial patellofemoral ligament (MPFL) reconstruction in patients with recurrent lateral patellar instability. Institutional ethical approval was obtained prior to initiation, and informed consent was taken from all participants.
2.2 Patient selection
Patients aged 15 to 40 years presenting with two or more episodes of lateral patellar dislocation and indicated for isolated MPFL reconstruction were included in the study.
Exclusion criteria comprised skeletally immature patients, those with concomitant ligamentous injuries, previous patellar fractures, or a history of tibial tuberosity transfer. All eligible patients underwent detailed clinical examination, radiographic evaluation, and magnetic resonance imaging (MRI) to confirm diagnosis and assess suitability for isolated MPFL reconstruction.
2.3 Group allocation
Based on convenience sampling, a total of 30 patients meeting the inclusion criteria were enrolled and divided into three equal groups (n = 10 per group) based on the graft and fixation technique employed:Group 1 (G1): Semitendinosus or gracilis autograft with suture anchor fixation at the patella and interference screw fixation at the femur.Group 2 (G2): Semitendinosus or gracilis autograft with implant less patellar fixation and femoral screw fixation.Group 3 (G3): Quadriceps tendon autograft with femoral screw fixation.
Group allocation was performed using a sequential enrolment method, and all procedures were executed by experienced orthopaedic surgeons specializing in knee reconstruction to minimize technique-related variability.
2.4 Surgical technique
All patients were operated on under regional or general anaesthesia using a standardized medial parapatellar approach. In Groups 1 and 2, the semitendinosus or gracilis tendon was harvested through a small incision over the pes anserinus, prepared, and fashioned to an appropriate length (Fig. 1(a)). For Group 1, patellar fixation was achieved using suture anchors (Fig. 1(b)), while Group 2 utilized an implant less looping technique through patellar bone tunnels (Fig. 1(c)–(d), Fig. 1(e)).
In Group 3, a partial-thickness quadriceps tendon autograft was harvested and fixed to the patella in a fan-shaped configuration (Fig. 2(a)). In all groups, femoral tunnel placement was guided fluoroscopically according to Schottle's point, ensuring anatomic reconstruction of the native MPFL (Fig. 2(b)). Femoral fixation was performed using an interference screw (Fig. 2(c)). Proper graft tensioning was ensured at 30° of knee flexion to restore physiological patellar tracking (Fig. 2(d)).
2.5 Postoperative rehabilitation
A uniform rehabilitation protocol was followed across all groups.
Immediate postoperative phase (0–2 weeks): Knee immobilization in extension with gradual initiation of passive range of motion from day 3.
Early rehabilitation phase (2–6 weeks): Progressive flexion exercises and partial weight-bearing with crutches.
Late rehabilitation phase (6–12 weeks): Full weight-bearing as tolerated and strengthening of the quadriceps and hip abductors.
Return-to-sport phase (after 3 months): Sport-specific drills were introduced following satisfactory clinical recovery and patient confidence.
2.6 Outcome measures
Clinical and functional outcomes were evaluated preoperatively and at 3, 6, and 12 months postoperatively using the following standardized scoring systems (Table-1):•Kujala Anterior Knee Pain Scale•Lysholm Knee Score•Tegner Activity Scale•Time to return to sports•Patient-reported satisfaction score (on a 10-point Likert scale)
| Outcome Measure | Purpose | Items/Description | Scoring Range | Interpretation |
| Kujala Anterior Knee Pain Scale (KAKPS) 7 | Evaluates anterior knee pain and patellofemoral function | 13 items: pain, limping, walking, running, squatting, sitting, stairs, swelling, thigh atrophy | 0–100 | 95–100: Normal85–94: Mild disability65–84: Moderate disability<65: Severe disability |
| Lysholm Knee Score 8 | Assesses knee function, esp. after ligament injuries | 8 items: limp, support, locking, instability, pain, swelling, stairs, squatting | 0–100 | 95–100: Excellent84–94: Good65–83: Fair<65: Poor |
| Tegner Activity Scale 9 | Evaluates activity/sports level | 0–10 scale: from sick leave/disability to elite competitive sports | 0–10 | 0Sick leave/disability1Sedentary work/no sports2Light labor/light recreational sports3Moderate labor/light recreational sports (cycling, walking)4Moderate recreational sports (swimming, jogging)5Heavy labor or recreational sports (skiing, running, tennis)6Recreational sports at competitive level (soccer, basketball)7Lower-division competitive sports8High-level competitive sports (national competitions)9Top national or semi-professional level sports10Elite competitive sports (international/professional level) |
| Time to Return to Sports | Measures speed of functional recovery | Days from surgery until cleared for previous activity | Days | Shorter = faster recovery |
| Patient Satisfaction Score | Reflects subjective satisfaction with surgery | Likert scale (1–10) | 1–5 (or 1–10) | 1–4: Unsatisfied5-6: Neutral7–10: Satisfied |
Any complications, such as graft failure, stiffness, or patellar re-dislocation, were documented.
2.7 Statistical method
Data were analyzed using Python with Jupyter Notebook IDE. Continuous variables were expressed as mean ± standard deviation (SD), and categorical variables as frequencies and percentages. Intergroup comparisons were performed using one-way analysis of variance (ANOVA) for continuous variables and the Chi-square test for categorical data. A p-value <0.05 was considered statistically significant.
3 Results
3.1 Participants
A total of 30 patients (10 in each group) underwent medial patellofemoral ligament (MPFL) reconstruction using one of three techniques: Group 1 (G1) – semitendinosus/gracilis graft with suture anchor fixation; Group 2 (G2) – semitendinosus/gracilis graft with implant less patellar fixation; and Group 3 (G3) – quadriceps tendon graft with femoral screw fixation. All patients completed a minimum of 12 months of postoperative follow-up. No patients were lost to follow-up. The demographic and baseline clinical characteristics of the participants were comparable across the three groups.
3.2 Descriptive data
The mean age of participants was 27.8 ± 6.4 years, ranging from 18 to 40 years. There were 17 males (56.7%) and 13 females (43.3%). The mean height and weight of the study population were 159.8 ± 7.5 cm and 59.3 ± 8.1 kg, respectively, corresponding to a mean BMI of 23.1 ± 2.9 kg/m2, which falls within the normal range for the Indian population.
The average operative time across all groups was 94.6 ± 18.3 min, with Group 1 showing slightly higher operative duration compared to the other two groups, though not statistically significant. Preoperative functional scores (Kujala, Lysholm, and Tegner) were similar among the groups, indicating comparable baseline function prior to surgery. Baseline demographic and clinical characteristics of participants are summerised in Table 2.
| Parameter | Overall (n = 30) | Group 1 (n = 10) | Group 2 (n = 10) | Group 3 (n = 10) | p-value |
| Age (years) | 27.8 ± 6.4 | 28.2 ± 5.9 | 27.1 ± 6.8 | 28.0 ± 6.6 | 0.87 |
| Gender (M/F) | 17/13 | 6/4 | 5/5 | 6/4 | 0.91 |
| Height (cm) | 159.8 ± 7.5 | 160.4 ± 7.8 | 158.7 ± 7.1 | 160.3 ± 7.6 | 0.79 |
| Weight (kg) | 59.3 ± 8.1 | 60.1 ± 8.5 | 58.6 ± 7.9 | 59.2 ± 8.0 | 0.83 |
| BMI (kg/m2) | 23.1 ± 2.9 | 23.3 ± 3.0 | 22.8 ± 2.6 | 23.2 ± 3.1 | 0.88 |
| Operation time (min) | 94.6 ± 18.3 | 97.5 ± 19.2 | 91.8 ± 17.4 | 94.5 ± 18.1 | 0.74 |
| Kujala Pre-op | 63.8 ± 6.5 | 65.1 ± 7.1 | 62.9 ± 5.8 | 63.4 ± 6.6 | 0.69 |
| Lysholm Pre-op | 52.1 ± 8.9 | 53.2 ± 9.4 | 51.7 ± 8.2 | 51.3 ± 9.1 | 0.77 |
| Tegner Pre-op | 3.8 ± 1.4 | 3.7 ± 1.3 | 3.6 ± 1.5 | 4.0 ± 1.3 | 0.83 |
3.3 Main results
To evaluate changes in functional outcomes over time and to compare the effectiveness of different surgical techniques, a two-way repeated measures analysis of variance (ANOVA) was performed (see Table 3). The analysis examined the main effects of group (surgical technique), timepoint (follow-up interval), and their interaction on patient-reported outcome measures, including the Kujala score, Lysholm score, and Tegner activity scale. The results of this analysis are summarized in the Tables 3 and 4 (A,B,C) below,
| Outcome | Factor | Sum Sq. | df | F | p-value | Statistical Significance |
| Kujala | Group | 61.67 | 2 | 0.47 | 0.626 | Not Significant |
| Timepoint | 11540.70 | 3 | 58.59 | 1.46 × 10−22 | Significant | |
| Group × Timepoint | 381.20 | 6 | 0.97 | 0.451 | Not Significant | |
| Residual | 7090.80 | 108 | — | — | — | |
| Lysholm | Group | 64.52 | 2 | 0.34 | 0.711 | Not Significant |
| Timepoint | 21930.16 | 3 | 77.63 | 7.65 × 10−27 | Significant | |
| Group × Timepoint | 555.82 | 6 | 0.98 | 0.440 | Not Significant | |
| Residual | 10169.50 | 108 | — | — | — | |
| Tegner | Group | 1.95 | 2 | 0.54 | 0.585 | Not Significant |
| Timepoint | 172.43 | 3 | 31.75 | 8.56 × 10−15 | Significant | |
| Group × Timepoint | 6.05 | 6 | 0.56 | 0.764 | Not Significant | |
| Residual | 195.50 | 108 | — | — | — |
| A. Kujala Score | |||||
| Comparison | Mean Diff | Lower CI | Upper CI | p-value | Significant |
| G1 vs G2 | 2.1 | −7.41 | 11.61 | 0.849 | No |
| G1 vs G3 | 3.8 | −5.71 | 13.31 | 0.589 | No |
| G2 vs G3 | 1.7 | −7.81 | 11.21 | 0.898 | No |
| B. Lysholm Score | |||||
| Comparison | Mean Diff | Lower CI | Upper CI | p-value | Significant |
| G1 vs G2 | −2.4 | −14.60 | 9.80 | 0.878 | No |
| G1 vs G3 | −3.0 | −15.20 | 9.20 | 0.816 | No |
| G2 vs G3 | −0.6 | −12.80 | 11.60 | 0.992 | No |
| C. Tegner Score | |||||
| Comparison | Mean Diff | Lower CI | Upper CI | p-value | Significant |
| G1 vs G2 | −0.5 | −1.90 | 0.90 | 0.656 | No |
| G1 vs G3 | −0.4 | −1.80 | 1.00 | 0.762 | No |
| G2 vs G3 | 0.1 | −1.30 | 1.50 | 0.983 | No |
The Table 3 summarizes the repeated measures ANOVA conducted for Kujala, Lysholm, and Tegner scores across three study groups and four timepoints. Significant effects were observed only for the Timepoint factor across all three outcome measures, indicating that scores improved over time regardless of the group (Fig. 3). No significant group differences or interaction effects were detected.
The Table 4 presents post-hoc Tukey HSD comparisons between the three groups at the 12-month follow-up for Kujala, Lysholm, and Tegner scores. None of the comparisons reached statistical significance, indicating comparable performance among all groups.
The Table 5 summarizes the comparison of secondary outcomes (patient satisfaction and return-to-sports duration). No significant differences were observed between the study groups.
| Outcome | F Statistic | p-value | Interpretation |
| Patient Satisfaction | 0.14 | 0.873 | No significant difference |
| Return to Sports (days) | 2.59 | 0.094 | No significant difference |
Analysis of secondary outcomes at 12 months demonstrated no statistically significant differences among the three groups. Patient satisfaction scores increased progressively over time in all groups, with comparable levels of satisfaction achieved at final follow-up (F = 0.14, p = 0.873), as illustrated in Fig. 4. Similarly, the mean time required to return to sports did not differ significantly between groups (F = 2.59, p = 0.094), although a trend toward earlier return was observed in Group 3 (Fig. 4). Overall, these findings indicate that patient-perceived satisfaction and functional recovery timelines were similar across the different MPFL reconstruction techniques.
3.4 Presentation
4 Discussion
In this prospective comparative study of 30 patients undergoing medial patellofemoral ligament (MPFL) reconstruction, we evaluated three commonly used surgical techniques, hamstring autograft with patellar suture anchor fixation (G1), hamstring autograft with implant less patellar fixation (G2), and quadriceps tendon autograft (G3). The three groups were demographically comparable at baseline, and preoperative functional scores did not differ significantly. At a minimum of 12 months of follow-up, all groups demonstrated significant improvement in Kujala, Lysholm, and Tegner scores over time; however, no statistically significant differences were observed between the three techniques in either repeated-measures ANOVA or Tukey post-hoc comparison. Secondary outcomes, including patient satisfaction and return-to-sports times, were also comparable. Within the limits of the present sample size, these findings suggest that all three reconstructive approaches yielded comparable short-term clinical outcomes rather than demonstrating definitive equivalence. Our results are consistent with the study by Astur et al. who compared EndoButton and suture anchor fixation and reported similar postoperative functional outcomes between techniques.10 Although their analysis identified better short-term results and higher complication rates with EndoButton fixation, such time-dependent variation and complication-related differences were not observed in our cohort. The alignment between both studies supports the broader observation that several fixation strategies can yield equivalent early functional recovery when performed using sound anatomical principles. Biomechanical insights from Lenschow et al. offer additional context. Their comparative analysis of five patellar fixation techniques demonstrated that most methods including anchors and trans osseous sutures provided adequate structural integrity, with inferior performance observed only in the bone-bridge technique.11 The techniques evaluated in our study fall within the mechanically robust category identified by Lenschow et al. which may explain the absence of significant differences in clinical outcomes between G1, G2, and G3. This reinforces the concept that once fixation strength surpasses a minimum biomechanical threshold, patient-reported outcomes are more strongly influenced by surgical accuracy than by fixation choice. When considering graft configuration, both Wang et al. and Kang et al. reported superior long-term stability or marginally higher functional scores with double-bundle anatomic reconstructions compared with single-bundle or alternative double-bundle configurations.12,13 Although our study did not directly compare single versus double-bundle constructs, the similarity of outcomes across three distinct graft–fixation combinations in our cohort aligns with their conclusion that anatomical reconstruction regardless of graft type, effectively restores patellar stability. The small clinical differences reported in these studies also highlight that improvements in graft configuration may offer incremental rather than transformative benefits in the absence of malalignment pathology. A broader synthesis provided by Kay et al. underscores the lack of consensus regarding the optimal graft type, fixation method, or technical variation for MPFL reconstruction despite a large and growing evidence base.14 Their scoping review involving more than 10,000 patients concluded that clinical outcomes are generally favorable across numerous techniques and that failures are more commonly attributed to femoral tunnel malposition than to graft or fixation selection. Our findings strongly align with this perspective, as all three techniques in our study performed similarly when key anatomical principles were respected.
Taken together, the present study adds prospective comparative data evaluating three commonly used graft–fixation strategies within a single standardized surgical and rehabilitation framework: hamstring autograft with patellar suture anchor fixation (G1), hamstring autograft with implant-less patellar fixation (G2), and quadriceps tendon autograft (G3). By directly comparing these techniques under uniform operative conditions, the study provides practical clinical insight into technique selection in routine practice. Although the sample size limits definitive conclusions regarding superiority or equivalence, the comparable short-term outcomes observed among G1, G2, and G3 suggest that satisfactory results can be achieved with multiple technically sound approaches. These findings underscore the importance of anatomical femoral tunnel placement, surgical precision, and individualized patient considerations in influencing clinical outcomes.
5 Limitations & strength
This study has several strengths, including its prospective design and direct comparison of three commonly used MPFL reconstruction techniques performed according to standardized anatomical principles. This study utilized validated functional outcome scores including Kujala score, Lysholm score, and Tegner activity scale, which are widely accepted for evaluating clinical outcomes following MPFL reconstruction.
However, the relatively small sample size limits statistical power, and the absence of statistically significant differences should not be interpreted as definitive evidence of equivalence. In addition, important anatomical risk factors such as trochlear dysplasia severity, TT–TG distance, patellar height, and limb alignment were not quantitatively analyzed. Although patients requiring additional bony corrective procedures were excluded. The addition of imaging-based and objective stability assessments could have provided further insight into graft integrity and patellofemoral alignment. The single-centre design and relatively short follow-up period may also limit generalizability. Larger, adequately powered studies with comprehensive clinical and radiological evaluation are warranted to confirm these findings.
6 Conclusion
This study demonstrates that the three MPFL reconstruction techniques evaluated, hamstring autograft with suture anchor fixation, hamstring autograft with implant less patellar fixation, and quadriceps tendon autograft, provide comparable short-term clinical outcomes. All patients showed significant improvement in knee function and stability at 12 months, with no meaningful differences in functional scores, patient satisfaction, or return-to-sport timelines among the groups. These findings suggest that different graft and fixation choices can achieve equally effective results when the procedure is performed with sound anatomical technique. Within the limitations of this small prospective cohort, all three techniques demonstrated similar short-term improvements. However, the study may be underpowered to detect small but clinically meaningful differences. Larger randomized studies with adequate sample size and long-term follow-up are required before definitive conclusions regarding equivalence can be made. Long-term follow-up studies with larger samples are warranted to determine whether subtle distinctions between these techniques emerge over time.
Availability of data and material
De-Identified data may be available to other researchers on request to the corresponding author subject to sufficient justification.
CRediT author statement
Swarnendu Samanta: Conceptualization; Methodology; Supervision Arnab Karmakar: Conceptualization; Methodology; Supervision; Corresponding Author. Arindam Chatterjee: Investigation; Data curation. Kevin G. Vadadoriya: Investigation; Data curation. Arkaprabha Sau: Methodology; Formal analysis; Data curation; Visualization; Writing – original draft; Writing – review & editing. All authors: Writing – review & editing; Approval of the final manuscript; Accountability for all aspects of the work.
Ethical approval and patient consent
All procedures performed were in accordance with the standards of the Ethics committee of the Institute of Post Graduate Medical Education & Research (S.S.K.M. Hospital) and Peerless Hospital, Kolkata, India and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. All patients provided written consent before being admitted for surgery.
Funding
The authors did not receive any funding from any organization for the submitted work. The authors have no conflicts of interest to declare that are relevant to the content of this article.
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