Table 1: Details of the inclusion and exclusion criteria.

Figure 1: X-ray of a broken knee joint.

Figure 2: X-ray of a knee joint.

All participants underwent clinical assessments at baseline, 3 months, 6 months and 12 months post-treatment, followed by annual evaluations up to 5 years. Outcomes were measured using the Knee Society Score (KSS), which evaluates pain, range of motion and stability and the Visual Analog Scale (VAS) for pain. The primary outcome was functional improvement; secondary outcomes included progression to TKA and adverse events.

Statistical analysis was performed using SPSS v25. Repeated-measures ANOVA was used to compare intra-group and inter-group changes over time, with a significance level set at p < 0.05.

Results

At baseline, both groups presented with similar mean KSS and VAS scores, with Group A (HA) starting at 45.6 ± 4.8 and 7.2 ± 0.6, respectively and Group B (PFO) at 46.1 ± 5.1 and 7.4 ± 0.5. After one year, Group A showed a modest clinical improvement with mean KSS reaching 59.3 ± 6.1 and VAS declining to 5.8 ± 0.9. However, the outcomes in Group B were significantly superior at the same timepoint, with mean KSS increasing to 78.9 ± 7.4 and VAS decreasing to 3.1 ± 1.0. At the two-year follow-up, deterioration in Group A was evident as 15 patients required Total Knee Arthroplasty (TKA) and the remaining 7 received a second cycle of HA injections. In contrast, only one patient in Group B required TKA during this same interval. Notably, one patient from the PFO group experienced transient partial peroneal nerve palsy, which resolved entirely within four weeks. By the third year, all patients in Group A had converted to TKA, reflecting the limited durability of the HA treatment. Meanwhile, the clinical status of the remaining Group B patients remained stable. During the fourth year, three additional patients in the PFO group underwent TKA, but by the fifth and final follow-up, 20 of the original 25 patients in Group B remained functional without requiring joint replacement, with sustained improvement in KSS (82.5 ± 6.9) and VAS (2.9 ± 0.8). Repeated-measures ANOVA confirmed statistically significant differences between groups beginning at 12 months and maintained throughout the 5-year period (p < 0.001).

Discussion

The management of advanced medial compartment knee OA remains a clinical challenge, particularly in patients who are either unwilling or unable to undergo Total Knee Arthroplasty (TKA). In this context, Proximal Fibular Osteotomy (PFO) has emerged as a viable joint-preserving surgical option. Our study provides one of the few comparative analyses with long-term follow-up, showing that PFO is not only superior to Hyaluronic Acid (HA) injections in symptom control but also effective in delaying or avoiding TKA in most cases. The biomechanical rationale for PFO is based on altering the load distribution across the knee joint. By weakening the lateral cortical support provided by the fibula, medial compartment pressure is reduced, which can improve varus alignment and decrease pain [2-4]. These effects are particularly evident in patients with isolated medial OA and no significant flexion deformity, as confirmed by our inclusion criteria.

Our findings demonstrate that while HA injections offered mild and temporary relief, they failed to prevent disease progression, with all patients ultimately requiring TKA. This is consistent with meta-analyses and clinical guidelines, which recognize HA as offering only limited benefit in moderate-to-severe OA [5-7]. Moreover, patients receiving HA required multiple procedures and follow-ups, further increasing indirect costs.

In contrast, PFO provided durable benefits for most patients. By year five, 80% of those treated with PFO remained functionally active without undergoing TKA. The only complication recorded was a transient peroneal nerve paresis, which resolved spontaneously within four weeks-a rate consistent with previous reports [8,9].

A particularly relevant consideration is the potential role of PFO in developing countries. In regions like Latin America, public healthcare systems may face waiting periods of 2-4 years for TKA, either due to resource constraints or bureaucratic delays. In such scenarios, PFO serves as a cost-effective and low-risk intervention that can significantly improve quality of life and delay the need for definitive surgery [10,11]. Our results are supported by similar studies from China and India, where PFO has been associated with improved joint mechanics, gait function and patient satisfaction over 3-5 years [12-14]. Some researchers have even suggested that radiographic changes post-PFO correlate with symptom improvement, although this remains controversial [15]. While promising, it is important to recognize that PFO is not curative. Its success depends on strict patient selection-namely absence of flexion contracture, lateral OA or advanced patellofemoral involvement. Moreover, long-term biomechanical consequences beyond 5 years remain unclear, necessitating future prospective and randomized studies with imaging follow-up.

Strengths and Limitations

This study has several notable strengths. It presents a unique five-year follow-up of patients treated with Proximal Fibular Osteotomy (PFO) compared to Hyaluronic Acid (HA) injections, offering real-world evidence from a single-practice, standardized approach. The long-term observation period provides robust insight into the durability of outcomes, especially for patients ineligible or unwilling to undergo Total Knee Arthroplasty (TKA). Additionally, all procedures and evaluations were performed by the same surgical team, reducing variability in technique and follow-up.

However, this study also has limitations. First, the sample size was relatively small, which may limit generalizability. Second, the retrospective design introduces potential for selection bias, despite inclusion of consecutive patients meeting strict criteria. Third, radiographic and biomechanical data were not systematically analyzed, which could have added objective confirmation of clinical improvement. Finally, the lack of randomization and blinding may have introduced observational bias. Future prospective, controlled studies with larger cohorts are necessary to validate these findings.

Conclusion

Proximal fibular osteotomy significantly outperforms hyaluronic acid injections in preserving joint function and delaying total knee arthroplasty in patients with advanced medial knee osteoarthritis. Beyond its biomechanical efficacy, PFO offers a valuable alternative for patients who are unwilling to undergo joint replacement or for those in developing countries where access to arthroplasty may be delayed for years. Given its low cost, minimal invasiveness and sustained benefits, PFO should be considered a viable joint-preserving strategy in carefully selected cases.

Conflict of Interests

The author declares no conflict of interest.

Funding/Sponsorship

This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.

Consent for Publication

Not applicable.

Acknowledgments

None.

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