The effect of partial fibulectomy on contact pressure of the knee: a cadaveric study

In-silico study of the biomechanical effects of proximal-fibular osteotomy on knee joint contact pressure in varus-valgus misalignment

The aim of this work is to investigate in-silico the biomechanical effects of a proximal fibular osteotomy (PFO) on a knee joint with different varus/valgus deformities on the progression of knee osteoarthritis (KOA). A finite element analysis (FEA) of a human lower extremity consisting of the femoral, tibial and fibular bones and the cartilage connecting them was designed. The FEA was performed in a static standing primitive position to determine the contact pressure (CP) distribution and the location of the center of pressure (CoP). The analysis examined the relationship between these factors and the degree of deformation of the hip-knee angle in the baseline condition. The results suggested that PFO could be a simple and effective surgical treatment for patients with associated genu varum. This work also reported that a possible CP homogenization and a CoP correction can be achieved for medial varus deformities after PFO. However, it reduced its effectiveness for tibial origin valgus misalignment and worsened in cases of femoral valgus misalignment.

Paradoxical Change in Subchondral Bone Density in the Medial Compartment of the Proximal Tibial Articular Surface After High Tibial Osteotomy: A Detailed Subchondral Bone Density Analysis

BACKGROUND

High tibial osteotomy (HTO) aims to realign the varus knee to alleviate stress in the medial compartment. However, detailed information on the impact of HTO on stress distribution across the tibiofemoral joint surface still needs to be completely elucidated.

PURPOSE/HYPOTHESIS

The present study aimed to analyze the subchondral bone density distribution to validate the alignment threshold causing paradoxical changes. We hypothesized that there would be a paradoxical stress change in the medial compartment beyond a specific threshold for lower limb realignment after HTO.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective clinical study of 32 knees from 30 patients who underwent medial opening-wedge HTO between 2015 and 2019 was conducted at Hokkaido University Hospital. The subchondral bone density across the tibiofemoral joint was analyzed using computed tomography-osteoabsorptiometry before and after HTO. The high-density area (HDA) within the medial and lateral compartments and their subregions, which were quartered in the coronal plane, was specifically examined.

RESULTS

The hip-knee-ankle angle, medial proximal tibial angle (MPTA), joint line obliquity (JLO), and joint line convergence angle significantly changed after HTO (P < .01). The HDA of the medial compartment to the total HDA ratio decreased from 83% to 77%. Paradoxically, the HDA in the most central subregion of the medial compartment increased from 24% to 30%. There were significant differences between MPTA and JLO in patients with and without paradoxical changes in the HDA. MPTA and JLO cutoff values causing paradoxical changes in the HDA were 94° and 4°, respectively.

CONCLUSION

There was a paradoxical stress increase in the M4 region at the medial compartment associated with the MPTA and JLO beyond specific thresholds. Therefore, surgical planning should be cautiously performed to prevent overcorrection, which can lead to adverse stress distribution changes.

Alternative Treatment of Gonarthrosis: Proximal Fibular Osteotomy

INTRODUCTION

Gonarthrosis is arthrosis of the knee joint, a chronic non-inflammatory disease manifested by progressive destruction of the intra-articular cartilage, accompanied by abnormal formation of the bones form the joint, changes in the synovial membrane and synovial fluid. Gonarthrosis is the most common type of arthrosis. Gonarthrosis can be treated conservatively and operatively. Among well-established surgical options for the treatment of medial gonarthrosis are high tibial osteotomy (HTO), unicompart-mental knee arthroplasty (UKA), and total knee arthroplasty (TKA). Proximal fibular osteotomy (PFO) or superior partial fibulectomy is a relatively recent procedure proposed to reduce knee pain in patients with medial compartment.

AIM

Our study aims to demonstrate an alternative treatment for gonarthrosis with proximal fibular osteotomy and reduced knee pain in patients with medial compartment osteoarthritis of the knee.

MATERIALS AND METHODS

At the Department of Orthopedics and Traumatology at J.Z.U "Borka Taleski" Prilep in the period from 2018 to 2021, 14 cases were treated, of which 11 were female and 3 were male. All patients were aged between 62 and 82 years with a mean age of 71.3 years. Patients had a severe degree of gonarthrosis (III/IV) according to Kellgren-Lawrence classification. Arthroscopy was performed in 2 patients. The fibula osteotomy was 7 cm away from the fibular head, with 1 cm resected bone fragment from the fibula.

RESULTS

The average duration of the surgery was 30 minutes. Patients were followed up on the 7th day, first month, 3 months and 6 months after surgery. The final evaluation of function was done after 6 months by examining the active and passive movements of the knee joint. In all 14 patients we have excellent results with pain reduction, improvement of movement and quality of life.

CONCLUSION

Proximal fibular osteotomy is an option for medial compartment osteoarthritis of the knee. Current literature is limited to small case series which report good outcomes in pain reduction, including the correction of varus deformity in medial gonarthrosis. Further studies are needed to determine the place of the PFO in the medial gonarthrosis management algorithm before it can be recommended for routine clinical use.

The association between unilateral high-riding vertebral artery and atlantoaxial joint morphology: a multi-slice spiral computed tomography study of 396 patients and a finite element analysis

BACKGROUND CONTEXT

A high-riding vertebral artery (HRVA) can deviate too medially, too posteriorly, or too superiorly to allow the safe insertion of screws. However, it is unknown whether the presence of a HRVA is associated with morphological changes of the atlantoaxial joint.

PURPOSE

To investigate the association between HRVA and atlantoaxial joint morphology in patients with and without HRVA.

STUDY DESIGN

A retrospective case-control study and finite element (FE) analysis.

PATIENT SAMPLE

A total of 396 patients with cervical spondylosis underwent multi-slice spiral computed tomography (MSCT) of cervical spine at our institutions from 2020 to 2022.

OUTCOME MEASURES

A series of atlantoaxial joint morphological parameters, including C2 lateral mass settlement (C2 LMS), C1-2 sagittal joint inclination (C1-2 SI), C1-2 coronal joint inclination (C1-2 CI), atlanto-dental interval (ADI), lateral atlanto-dental interval (LADI), and C1-2 relative rotation angle (C1-2 RRA) were measured, and lateral atlantoaxial joints osteoarthritis (LAJs-OA) was recorded. The stress distribution on the C2 facet surface under different torques of flexion-extension, lateral bending, and axial rotation was analyzed by FE models. A 2-Nm moment was applied to all models to determine the range of motion (ROM).

METHODS

A total of 132 consecutive cervical spondylosis patients with unilateral HRVA were enrolled in the HRVA group, and 264 patients without HRVA matched for age and sex were enrolled in the normal (NL) group. Atlantoaxial joint morphological parameters were compared between two sides of C2 lateral mass within HRVA or NL group, and between HRVA and NL groups. A 48-year-old woman with cervical spondylosis without HRVA was selected for cervical MSCT. A three-dimensional (3D) FE intact model of the normal upper cervical spine (C0-C2) was created. We established the HRVA model by simulating atlantoaxial morphological changes of unilateral HRVA with FE method.

RESULTS

The C2 LMS was significantly smaller on the HRVA side than that on the non-HRVA side in the HRVA group, but C1-2 SI, C1-2 CI, and LADI on HRVA side were significantly larger than those on non-HRVA side. There was no significant difference between left and right sides in the NL group. The difference in C2 LMS (d-C2 LMS) between HRVA side and non-HRVA side in the HRVA group was larger than that in the NL group (P < 0.05). Meanwhile, the differences in C1-2 SI (d-C1/2 SI), C1-2 CI (d-C1/2 CI), and LADI (d-LADI) in the HRVA group were significantly larger than those in the NL group. The C1-2 RRA in the HRVA group was significantly larger than that in the NL group. Pearson correlations showed that d-C1/2 SI, d-C1/2 CI, and d-LADI were positively associated with d-C2 LMS (r=0.428, 0.649, 0.498, respectively, p<.05 for all). The incidence of LAJs-OA in the HRVA group (27.3%) was significantly larger than that in the NL group (11.7%). Compared with the normal model, the ROM of C1-2 segment declined in all postures of the HRVA FE model. We found a larger distribution of stress on the C2 lateral mass surface of the HRVA side under different moment conditions.

CONCLUSIONS

We suggest that HRVA affects the integrity of the C2 lateral mass. This change in patients with unilateral HRVA is associated with the nonuniform settlement of the lateral mass and an increase in the lateral mass inclination, which may further affect the degeneration of the atlantoaxial joint because of the stress concentration on the C2 lateral mass surface.

Changes in the Tibial Strain After Proximal Fibular Osteotomy: A Biomechanical Cadaveric Study

Total knee arthroplasty surgery is an increasingly common procedure for the treatment of uni- and tricompartmental knee osteoarthritis, particularly in advanced stages and in the older population. Its usage is being extended to younger patients, where implant longevity is of concern. In the younger age group, especially with early disease, other options merit consideration. On the other hand, it may not be possible for elderly patients with medical comorbidities to undergo joint replacement surgery. Proximal fibular osteotomy (PFO) has recently been advocated to treat medial knee osteoarthritis. Although there have been clinical reports showing promising outcomes, the biomechanical basis of this procedure is still unclear. We performed a cadaveric study to investigate the effect of PFO on proximal tibial strain. Eight unpaired cadaveric lower limb specimens were loaded in compression at 2 times body weight. Strain gauges were mounted on various sites on the proximal tibia and fibula. After PFO, there was a significant increase in the lateral tibial strain adjacent to the proximal tibiofibular joint (P<.05). There was moderate effect size reduction in the anteromedial tibial strain as well as moderate effect size increase in the posterior tibial strain. The strain reduction seen at the anteromedial tibia can offer a possible explanation for symptomatic relief after PFO. However, the increase in the lateral and posterior tibial strain raises concern about long-term accelerated wear in these regions. [Orthopedics. 2022;45(5):314-319.].

Proximal fibular osteotomy relieves pain in spontaneous osteonecrosis of the knee: A retrospective study

Spontaneous osteonecrosis of the knee (SONK) causes knee pain and joint motion limitation. Ischemia or insufficiency fracture may be the cause, but no consensus has been developed. Proximal fibular osteotomy (PFO) has been reported to relieve pain from osteoarthritis through medial compartment decompression. We reviewed the effect of this procedure on medial compartment SONK patients and explored clinical and radiological results. Since January 2018 to January 2020, the data of 12 knees (8 right and 4 left) from 11 SONK patients (9 women and 2 men) who received PFO were analyzed. The average age was 61.5 years. The diagnosis of SONK was established through weight-bearing anterior-posterior radiographs or magnetic resonance imaging (MRI). Visual analog scale (VAS) scores, Oxford knee score (OKS), Femorotibial angle (FTA), medial joint space, and lateral joint space were documented preoperatively and at follow up visits. Outcome assessment for the clinical and radiographic data was reviewed at 12- and 24-month follow-up visits. The mean follow up period was 33 months. All patients were able to walk with or without cane assistance the day after surgery. Both VAS score and OKS (preoperative: 6.6 ± 0.9 and 24.7 ± 3.8, respectively) improved significantly at the 12-month follow-up, and to 24-month follow-up (3.6 ± 1.3 and 35.6 ± 4.5, respectively, P < .05). Medial joint space ratio increased from 0.36 to 0.50 (P < .05). Changes of FTA were insignificant at any point of follow up. Four patients underwent follow-up MRI, and a decrease in the osteonecrotic area was clearly observed in 2 patients. By achieving medial knee decompression, PFO allowed quick weight-bearing recovery, pain relief, and improvement in knee function in SONK patients.

Tibia Stress Fracture and Subsequent Nonunion Associated With High Morbidity Following Vascularized Fibula Graft Harvest

There is little in the literature about tibial stress fracture after partial fibulectomy. As fibula strut grafting and vascularized fibula flap grafting becomes more common in the field of reconstructive surgery, the incidence of this complication will likely rise. The authors present the case of a 54-year-old woman with tibial stress fracture and subsequent nonunion following vascularized fibula graft harvest. The aim of this case report is to present a unique tibial stress fracture and nonunion following vascularized fibula flap for mandibular reconstruction and a discussion of the orthopedic management of this uncommon injury. The authors' goal is to educate both surgeons and patients about the altered biomechanics and subsequent risks associated with fibula strut graft harvest, from an orthopedic surgery perspective. By increasing physician awareness and obtaining better informed consent preoperatively, better health care outcomes associated with fibular graft harvesting can be obtained. [Orthopedics. 2021;44(2):e306-e308.].

Proximal Tibiofibular Dislocation in Closing-Wedge High Tibial Osteotomy Increases the Risk of Medium and Long-Term Total Knee Replacement

Proximal tibiofibular dislocation in closing-wedge high tibial osteotomy increases the risk of medium and long-term total knee replacement. Background: High tibial osteotomy is an effective treatment for medial osteoarthritis in young patients with varus knee. The lateral closing-wedge high tibial osteotomy (CWHTO) may be managed with tibiofibular dislocation (TFJD) or a fibular head osteotomy (FHO). TFJD may lead to lateral knee instability and thereby affect mid- and long-term outcomes. It also brings the osteotomy survival rate down. Objective: To compare the CWHTO survival rate in function of tibiofibular joint management with TFJD or FHO, and to determine whether medium and long-term clinical outcomes are different between the two procedures. Material & Methods: A retrospective cohort study was carried out that included CWHTO performed between January 2005 to December 2018. Those patients were placed in either group 1 (FHO) or Group 2 (TFJD). Full-leg weight-bearing radiographs were studied preoperatively, one year after surgery and at final follow-up to assess the femorotibial angle (FTA). The Rosenberg view was used to assess the Ahlbäck grade. The Knee Society Score (KSS) was used to assess clinical outcomes and a Likert scale for patient satisfaction. The total knee replacement (TKR) was considered the end of the follow-up and the point was to analyze the CWHTO survival rate. A sub-analysis of both cohorts was performed in patients who had not been FTA overcorrected after surgery (postoperative FTA ≤ 180°, continuous loading in varus). Results: A total of 230 knees were analyzed. The follow-up period ranged from 24-180 months. Group 1 (FHO) consisted of 105 knees and group 2 (TFJD) had 125. No preoperative differences were observed in terms of age, gender, the KSS, FTA or the Ahlbäck scale; neither were there any differences relative to postop complications. The final follow-up FTA was 178.7° (SD 4.9) in group 1 and 179.5° (SD 4.2) in group 2 (p = 0.11). The Ahlbäck was 2.21 (SD 0.5) in group 1 and 2.55 (SD 0.5) in group 2 (p = 0.02) at the final follow-up. The final KSS knee values were similar for group 1 (86.5 ± 15.9) and group 2 (84.3 ± 15.8). Although a non-significant trend of decreased HTO survival in the TFJD group was found (p = 0.06) in the sub-analysis of non-overcorrected knees, which consisted of 52 patients from group 1 (FHO) and 58 from group 2 (TFJD), 12.8% of the patients required TKR with a mean of 88.8 months in group 1 compared to 26.8% with a mean of 54.9 months in the case of group 2 (p = 0.005). However, there were no differences in clinical and radiological outcomes. Conclusion: TFJD associated with CWHTO shows an increase in the conversion to TKR at medium and long-term follow-up with lower osteotomy survival than the CWHTO associated with FHO, especially in patients with a postoperative FTA ≤ 180° (non-overcorrected). There were no differences in clinical, radiological or satisfaction results in patients who did not require TKR. Level of evidence III. Retrospective cohort study.

Comparison of Clinical and Radiological Outcomes Between Upper Fibular Curvature and Non-Curvature with Medial Knee Osteoarthritis Following Proximal Fibular Osteotomy: A Retrospective Cohort Study with Minimum 2-Year Follow-up

Objective

To evaluate and compare the clinical and radiographic outcomes of proximal fibular osteotomy (PFO) in treating medial knee osteoarthritis (KOA) patients with upper fibular curvature and non‐curvature.

Methods

A retrospective cohort study was performed. From January 2016 to January 2017, a total of 51 patients (nine males and 42 females) at a mean age of 63.7 years (range 48–79 years) with medial KOA who underwent PFO procedure at the Third Hospital of Hebei Medical University were included in the study. The patients were divided into the two groups, namely curvature group (28 patients, six males and 22 females, aged 62.6 ± 7.7 years) and non‐curvature group (23 patients, three males and 20 females, aged 64.5 ± 7.6 years). Perioperative parameters and Kellgren‐Lawrence classification were recorded and analyzed in the two groups, respectively. All patients were followed up at 1, 3, 6, and 12 months at the first year of post‐operation, and then every 6 months from the second year of post‐operation. A telephone survey with standard questionnaire survey, including Visual Analog Scale (VAS) score and Hospital for Special Surgery (HSS) scoring system, was used to evaluate postoperative clinical outcomes. Radiological results were assessed using the femorotibial angle (FTA), hip‐knee‐ankle angle (HKA), and settlement value of medial tibial platform (MTP) in the two groups.

Results

The average follow‐up periods of the curvature group and the non‐curvature group were 34.8 ± 6.1 and 33.9 ± 5.4 months, respectively. There were no significant differences between the two groups of demographic data in terms of number of patients, age, body mass index (BMI), gender, KOA side, and Kellgren‐Lawrence classification (P > 0.05). The VAS scores of the curvature group and non‐curvature group were (3.53 ± 1.62 vs 3.68 ± 1.43 at 1 month, 3.46 ± 0.79 vs 3.57 ± 0.66 at 3 months, and 2.43 ± 0.88 vs 2.83 ± 0.94 at 6 months, both P > 0.05), while significant differences were found from 12 months post‐operation (1.54 ± 0.72 vs 2.03 ± 0.85 at 12 months, and 1.04 ± 0.69 vs 1.74 ± 0.75 at 24 months, both P < 0.05). The HSS scores of the curvature group and non‐curvature group were (79.67 ± 5.14 vs 78.25 ± 6.37 at 1 month, 84.65 ± 3.76 vs 83.18 ± 3.64 at 3 months, and 86.27 ± 3.13 vs 85.49 ± 3.25 at 6 months, both P > 0.05), while significant differences were found from 12 months post‐operation (90.64 ± 4.32 vs 87.71 ± 5.63 at 12 months, and 92.93 ± 2.07 vs 90.06 ± 2.08 at 24 months, both P < 0.05). In addition, the FTA and settlement value of the curvature group were lower than the non‐curvature group (177.18 ± 1.52 vs 178.35 ± 1.86, and 5.29 ± 1.74 vs 6.49 ± 2.09, both P < 0.05) while the HKA were higher than the non‐curvature group (175.32 ± 2.34 vs 173.83 ± 2.64, P < 0.05) at the final follow‐up.

Conclusions

Medial KOA patients with upper fibular curvature is an optimal surgical indication for PFO surgery, with the advantages of pain relief, better functional recovery, and alignment correction.

Proximal fibular osteotomy: Systematic review on its outcomes

BACKGROUND

The morbidity and burden of knee osteoarthritis affecting millions of lives worldwide has created a constant pursuit in finding the ideal treatment for knee osteoarthritis. There has been a paradigm shift in the surgical treatment of osteoarthritis ever since the initial description of Volkmann’s tibial osteotomy. This review focuses on one such recent procedure, the proximal fibular osteotomy (PFO) for medial compartment knee osteoarthritis. This review encompasses the history, evidence, risk factors, outcomes and technical considerations of PFO.

AIM

To understand the evidence and its techniques, and whether this could be an alternative solution to the problem of knee osteoarthritis in the developing world.

METHODS

The phrases “proximal fibular osteotomy” and “knee osteoarthritis” were searched (date of search December 20, 2019) on PubMed to identify articles evaluating the biomechanical and clinical outcomes of PFO in patients with knee osteoarthritis. A total of 258 were retrieved. After reviewing the summary of the texts, 22 articles written in English were marked for abstract review. Articles that were case studies or cadaver experiments were excluded. The abstracts of the remaining articles were read, and only those that focused on the history, outcomes of case studies and technical considerations of PFO were included in the review. A total of 12 articles were included in this review.

RESULTS

At least six studies reported improvement in the visual analogue scale(VAS) from the average preoperative VAS score [6.32, 95% confidence interval (CI) = (4.05, 8.59)] to average postoperative VAS score [1.23, 95%CI: (-1.20, 3.71)], which was statistically significant. Similarly, the American Knee Society Score (KSS) functional score improved from an average preoperative KSS functional score [43.11, 95%CI: (37.83, 48.38)] to postoperative KSS functional score [66.145, 95%CI: (61.94, 70.35)], which was statistically significant. The femorotibial angle improved by around 7^º, and the hip knee ankle angle improved by around 6^º.

CONCLUSION

With the existing data, it seems that PFO is a viable option for treating medial joint osteoarthritis in selected patients. Long term outcome studies and progression of disease pathology are some of the important parameters that need to be addressed by use of multicenter randomized controlled trials.

Proximal Fibular Osteotomy: Is it Really an Option for Medial Compartmental Osteoarthritis Knee? Our Experience at Tertiary Centre

INTRODUCTION

The medial compartment is commonly involved in age-related osteoarthritis knee because weight-bearing axis passes close to the medial condyle and its large surface area. Various treatments have been proposed ranging from conservative to total knee arthroplasty which is an expensive and complex treatment. Recently, proximal fibular osteotomy (PFO) for medial compartment knee osteoarthritis became popular as a treatment modality. Although, the mechanism of PFO is not clear. So, we conducted a prospective study to assess the clinico-radiological outcome of proximal fibular osteotomy in medial compartment osteoarthritis knee.

MATERIALS AND METHODS

We conducted a prospective study from November 2017 to November 2019 on 32 (47 knees) patients with degenerative medial compartmental osteoarthritis knee, varus deformity < 15 and Kellgren and Lawrence grade II and grade III (K-L Grade). We recorded the visual analogue score (VAS) and knee society score (KSS) pre-operatively and post-operatively of all patients.  We got weight bearing anterio-posterior and lateral radiograph of knee done. We assessed joint space ratio and lateral tibio-femoral angle (FTA) pre-operatively, post-operatively and at each follow-up.

RESULTS

Mean age was 48.4 (35-65) years and the mean follow-up was 18 months. Mean duration for unilateral PFO was 37 min and for bilateral, 55 min. The VAS was improved from 7.33 ± 0.72 to 7.13 ± 1.64 at 3 months and remained the same at final follow-up (p > 0.05). The mean pre-operative clinical and functional KSS was statistical insignificantly improved at 3 months and final follow-up (p > 0.05). The mean pre-operative lateral and mean pre-operative joint space ratio was also improved statistically insignificant (p > 0.05). Extensor hallucis longus (EHL) weakness was documented in five knees (10.6%) and paraesthesia was documented in seven (14.8%) knees.

CONCLUSION

Although, PFO is a simple, less invasive and affordable procedure, we could not reproduce the favourable results in medial compartmental osteoarthritis knee. This procedure is also associated with reversible but noticeable complications. So, we would not consider PFO as an alternative option in the treatment of medial compartmental osteoarthritis knee.

Changes in patellar height and posterior tibial slope angle following uniplanar medial opening wedge high tibial osteotomy using a novel wedge-shaped spacer implanation concurrent with proximal partial fibulectomy

PURPOSE

The purpose of this study was to evaluate changes of patellar height and posterior tibial slope angle following uniplanar medial opening wedge high tibial osteotomy using a novel wedge-shaped spacer implanation concurrent with proximal partial fibulectomy.

METHODS

All patients who underwent uniplanar medial opening wedge high tibial osteotomy using a novel wedge-shaped spacer implanation concurrent with proximal partial fibulectomy between January 2017 and February 2019 were included and assessed retrospectively. Radiological assessment was made in terms of the changes in patellar height and posterior tibial slope angle between pre-operative and post-operative radiographs.

RESULTS

Thirty-five patients (9 males and 26 females) with a mean age of 57.3 years (range 50.8-64.2 years) were enrolled in this study protocol and demonstrated decreased posterior tibial slope angle post-operatively (9.7° ± 2.5° pre-operatively and 7.3° ± 1.8° post-operatively, P < 0.001). Patellar height was unchanged significantly post-operatively (Caton-Deschamps: 0.83 ± 0.12 pre-operatively and 0.82 ± 0.09 post-operatively, P > 0.05).

CONCLUSIONS

Uniplanar medial opening wedge high tibial osteotomy using a novel wedge-shaped spacer implanation concurrent with proximal partial fibulectomy can decrease posterior tibial slope and maintain the patellar height.

Effects of proximal fibular osteotomy on stress changes in mild knee osteoarthritis with varus deformity: a finite element analysis

BACKGROUND

Many previous studies lack sufficient quantitative evidences about changes in biomechanical properties of the knee in response to proximal fibular osteotomy (PFO). Therefore, the aim of this study was to compare the preoperative and postoperative effects of PFO on mechanical stresses in the knee joint and provide with a biomechanical basis for PFO in the treatment of mild knee osteoarthritis (KOA) with varus deformity.

METHODS

A total of 10 patients suffering mild KOA with varus deformity were enrolled in this study. Their image data from computerized tomography (CT) and magnetic resonance imaging (MRI) were used for finite element models, and PFO models were established. Static structural analysis was carried out using ABAQUS to compare the von Mises stress distribution and values of the maximal von Mises stress of femoral cartilage, meniscuses, tibial cartilages, and tibial plateau before and after surgery.

RESULTS

The stress distribution in the cortical bone of the tibial plateau showed that stresses were transferred from the anterior medial area to the posterior medial area after PFO. Values of the maximal von Mises stress in femoral cartilage, medial meniscus, medial tibial cartilage, and tibial plateau after surgery were significantly lower than the preoperative values, with statistically significant differences (P < 0.05). Postoperative values of the maximal von Mises stress of lateral meniscus and lateral tibial cartilage were significantly higher than the preoperative ones, with statistically significant differences (P < 0.05).

CONCLUSION

PFO could reduce the stresses in the medial compartment of the knee joint with stress pathways transferring from the anterior medial area to the posterior medial area of the tibial plateau. Therefore, PFO is recommended for the treatment of mild KOA with varus deformity featuring favorably pain-relieving effects.

Proximal Fibular Osteotomy for Medial Compartment Knee Osteoarthritis: Is It Worth?

BACKGROUND

Osteoarthritis of knee is one of the important causes of knee pain in elderly patients and is a debilitating disease. It often leads to varus deformity of knee. Many treatment options are available for this progressive knee joint disorder. Proximal fibular osteotomy (PFO) is a novel yet simple procedure used to alleviate the symptoms of medial compartment knee osteoarthritis. The present study was undertaken to evaluate whether this procedure improves the symptoms, functions and limb alignment in patients with medial compartment knee osteoarthritis.

METHODS

Following approval by the Institutional Review Board, this prospective study included 42 cases (56 knees) with Kellgren-Lawrence grade II and III medial compartment knee osteoarthritis and underwent proximal fibular osteotomy. Clinical assessment was done by visual analogue scale (VAS) score and The Western Ontario and McMaster universities osteoarthritis Index (WOMAC) score pre-operatively and at 3, 6 and 12 months follow-up for pain and functional improvement. Radiological assessment was done by measuring femoro-tibial angles (FTA) pre-operatively and at 1 year follow-up.

RESULTS

The mean age was 58.30 years. There were 30 females and 12 males. The preoperative mean WOMAC score was 87.3, at 3 months follow-up it was 29.4 this was significantly better (p < 0.05) but the improvement was not significant at subsequent follow-up visits. Similarly the VAS scores also showed significant improvement at 3 months, but not at 6 and 12 months follow-up. There was no significant improvement in the femoro-tibial angle (FTA) at 1 year follow-up.

CONCLUSION

The study highlights that both the VAS scores and WOMAC scores were significantly better at 3 months after surgery. However these did not show any significant improvement at 6 and 12 months. It does not change the alignment of knee at one year follow-up. The authors conclude that proximal fibular osteotomy provides only short-term relief in patients of medial compartment knee osteo-arthritis.

Replacing one evil with another: Is the fibula really a dispensable spare part available for transfer in patients with medication-related osteonecrosis of the jaws?

Because of the long-term and consecutive use of different causative agents, clinicians are increasingly encountering patients needing restoration of the stomatognathic system after surgical resection of highly advanced necroses of the jaw. For plastic restoration in these cases, microvascular reconstruction seems to represent the most viable option. According to the limited data available, the risks of this operation are considered comparable with those faced by other patient cohorts. We report here the case of a patient who suffered 2 successive pathologic fractures of the tibia after microsurgical reconstruction of the mandible with a free fibula flap. This exemplifies a general problem, especially because the patient also suffered from a treatment-refractory infection of the transplanted bone. Although the present literature indicates otherwise, fibula transplants might not be the gold standard in these cases. Therefore, alternatives to transplants from the weight-bearing parts of the body need to be considered until more data are available.

Proximal fibular osteotomy in the treatment of medial osteoarthritis of the knee - A narrative review of literature

Proximal fibular osteotomy has been proposed as a simple and inexpensive alternative to high-tibial osteotomy and unicondylar knee arthroplasty and may be useful for low-income populations that cannot afford expensive treatment methods. However, there is no consensus existing regarding the mechanism by which it acts nor the outcome of this procedure. This study was performed to analyze the available evidence on the benefits of proximal fibular osteotomy and to understand the possible mechanisms in play. There are various mechanisms that are proposed to individually or collectively contribute to the outcomes of this procedure, and include the theory of non-uniform settlement, the too-many cortices theory, slippage phenomenon, the concept of competition of muscles, dynamic fibular distalization theory and ground reaction vector readjustment theory. The mechanisms have been discussed and future directions in research have been proposed. The current literature, which mostly consists of case series, suggests the usefulness of the procedure in decreasing varus deformity as well as improving symptoms in medial osteoarthritis. However, large randomised controlled trials with long-term follow-up are required to establish the benefits of this procedure over other established treatment methods.

Anatomical Adaptation of Fibula and its Mechanism of Proximal Partial Fibulectomy Associated with Medial Compartment Knee Osteoarthritis

Objectives

To reveal the anatomical adaptation of the fibula and its relations to age and settlement of the medial tibial plateau, and to explore the mechanism of proximal partial fibulectomy in treating medial compartment knee osteoarthritis (OA).

Methods

A retrospective study was performed in the Third Hospital of Hebei Medical University. Weight‐bearing full‐leg anteroposterior (AP) radiographs of 280 adults (560 knees) obtained from 1 January 2018 to 31 October 2018 were enrolled according to our inclusion and exclusion criteria, including 157 men and 123 women, with an average age of 50.3 ± 14.8 years (range, 19–80 years). Radiographic severity of knee OA was assessed using Kellgren and Lawrence (K–L) grading. The settlement of the medial tibial plateau was evaluated using the medial proximal tibial angle (MPTA). Curvatures of the tibia and the fibula were measured as proximal tibial curvature (PTC), distal tibial curvature (DTC), proximal fibular curvature (PFC), and distal fibular curvature (DFC). Two orthopaedic surgeons performed all the radiological measurements for 30 randomly selected patients, and repeated the measurements 1 week later. Based on the satisfactory intra‐observer and inter‐observer reliabilities (ICC > 0.9), each parameter was analyzed in this study. Multivariable linear regression models were used to examine relations between radiological measurements and age.

Results

The mean MPTA, PTC, DTC, PFC, and DFC were 85.4° ± 2.8°, 176.2° ± 1.9°, 176.8° ± 1.8°, 176.8° ± 1.9°, and 177.0° ± 2.0°, respectively. Ninety‐three knees of K–L grade I were categorized as non‐knee OA, and 467 knees of K–L grades II–IV were categorized as knee OA. The MPTA, PTC, and PFC of the knee OA group were significantly smaller than those of non‐knee OA group (P < 0.05). The K–L grade of knee OA significantly increased with age (χ² = 182.169, P < 0.01). The multivariate linear regression analysis indicated that the MPTA and fibular curvatures were negatively correlated with age (the regression equation is age = 561.165–0.945 MPTA‐0.937 PFC‐0.959 DFC, P < 0.05), and the MPTA was negatively correlated with PFC (the regression equation is MPTA = 7.827 + 0.099 DFC, P < 0.05).

Conclusions

The proximal curve of the fibula increased in patients with medial compartment knee OA, and this change was positively correlated with age and settlement of the medial tibial plateau. This anatomical adaptation of the fibula was associated with greater fibular axial load and the pulling from the peroneus longus. The proximal partial fibulectomy procedure effected a receptive foot pronation to reduce KAM and rebalance the biceps‐proximal fibula–peroneus longus complex, consequently achieving medial compartment unloading.

Kinematic Characteristics of an Osteotomy of the Proximal Aspect of the Fibula During Walking: A Case Report

CASE

A 51-year-old patient with medial compartment osteoarthritis of the left knee underwent an osteotomy of the proximal aspect of the fibula. Gait kinematic data were collected before and after the surgery with use of an optical tracking system during level walking. A sharp increase of approximately 5° to 7° in femoral abduction and a 5° to 8° increase in femoral external rotation were exhibited at 3 months postsurgery. At 1 year postsurgery, femoral external rotation had increased by 3° to 5°. There was also an increase of distal femoral translation (approximately 2 to 10 mm).

CONCLUSION

An osteotomy of the proximal aspect of the fibula altered the kinematics by increasing valgus, femoral external rotation, and distal translation of the knee. These alterations may help reduce knee pain and improve early functional recovery.

Medial Compartment Decompression by Proximal Fibular Osteotomy: A Biomechanical Cadaver Study

Medial compartment knee osteoarthritis is a painful and debilitating disease. A proximal fibular osteotomy is a novel, simple surgical technique that may reduce pain and improve function for patients with osteoarthritis. The purpose of this biomechanical cadaver study was to determine what effect proximal fibular osteotomy had on knee joint and ankle pressures and tibia strain. Ten matched pairs of cadaver legs were tested in compression to 1.1 times body weight comparing intact and with proximal fibular osteotomy at 0°, 15°, and 30° of flexion. Sensors were inserted into the knee and ankle joint to measure pressure, force, and contact area. Strain was measured with a strain gage on the anterior medial tibia. In the medial compartment, the peak force, contact area, and pressure all decreased from intact to after fibular osteotomy, with significant differences at 15° of flexion (P<.05). There were no significant differences in the lateral compartment for any measures. In the ankle joint, the peak force and pressure decreased from intact to after fibular osteotomy at all 3 flexion angles. There were no significant changes in strain in the tibia. Proximal fibular osteotomy decreases the pressure in the medial compartment of the knee, which may reduce knee pain and improve function in patients with medial compartment knee osteoarthritis. [Orthopedics. 2018; 41(4):e496-e501.].

Upper partial fibulectomy improves knee biomechanics and function and decreases knee pain of osteoarthritis: A pilot and biomechanical study

To investigate the change in clinical outcomes and biomechanical properties of the knee in response to upper partial fibulectomy. Sixteen patients with medial compartment knee osteoarthritis (KOA) underwent upper partial fibulectomy. Visual analog scale (VAS) pain, the hospital for special surgery knee score (HSS), hip-knee-ankle (HKA) angle (measured in the frontal plane), and flexion/extension range of motion of the knee were assessed before and up to 6 months after surgery. Patients were evaluated for gait parameters and overall peak knee adduction moment (KAM). Patient-specific finite element knee models were developed to investigate changes in load in response to fibulectomy. Both VAS pain and HSS score were significantly improved (P < .001) one day after surgery and steadily improved during the subsequent 6 months. HKA angle improved (P = .006) immediately and remained stable by 3 months after surgery. A significant inverse relationship (R = -0.528, P = .012) between the overall peak KAM (decreased by 19.1%) and the HKA (increased by 1.24° from a more varus to more neutral alignment) angle was observed. The minor load supported by the fibula preoperatively was spread post-operatively over the cortical bone of the tibial shaft. The mean stress in the medial tibial plateau was significantly decreased (P < .001), with a portion of the stress transferred to the posterior-lateral region of the tibial plateau after upper partial fibulectomy. This pilot study provides objective 3D gait and plausible biomechanical evidence for the improvement in clinical symptoms from partial upper fibulectomy.