Bilateral Subluxation of the Proximal Tibiofibular Joint: A Rare Case Report.

Introduction: Proximal tibiofibular joint (PTFJ) subluxations are rare and can occur following trauma or sporting events. Idiopathic PTFJ subluxations are more common in females and in patients with generalized ligament laxity. The proper history and clinical examination together with imaging can help in establishing the diagnosis in the majority of cases. Case Report: We report a rare case of bilateral subluxation of PTFJ and describe the detailed clinical features and magnetic resonance imaging findings. The patient was managed conservatively with good results. Conclusion: Bilateral subluxation of the PTFJ is a rare clinical entity often associated with specific demographic and physical characteristics, such as young females engaged in high-impact sports. This case underscores the importance of a thorough clinical and imaging evaluation to differentiate it from other causes of lateral knee pain and prominence. Conservative management, including physical therapy and routine follow-ups, has proven effective in managing symptoms and avoiding progression, highlighting the non-operative approach in treating this condition.

Morphology of the proximal tibiofibular joint does not affect the type of lateral malleolus fracture and syndesmotic ligament injuries: A computed tomography-based study.

INTRODUCTION: The Proximal Tibiofibular Joint (PTFJ) is a synovial joint with anatomical variations located between the anteromedial surface of the fibula and the posterolateral facet of the tibia. These anatomical variations are believed to contribute to different biomechanical behaviors in both the knee and ankle joint and play a role in both physiological and pathological movements. Therefore, the morphology of the proximal tibiofibular joint may play a decisive role in the characteristics of ankle fractures and syndesmotic ligament injuries. MATERIALS AND METHODS: In this retrospective comparative our CT database was searched between January 2015 and December 2022. Following inclusion criteria were used: Availability of knee CT scans for the fractured ankle, external rotation-type injuries (pronation external rotation and supination external rotation fractures). After applying the exclusion criteria (Plafond fractures, supination adduction and pronation abduction type fractures, pathological fractures, patients with previous fractures or surgeries around the knee, patients with previous fractures or surgeries around the knee, proximal tibiofibular arthrosis), 44 CT scans (mean age = 42.8 ± 14.1) confirmed eligible for further analysis. On each scan following measurements were performed: Coronal and sagittal PTFJ inclination angle, Joint obliquity, fibula head-tibia joint distance and tibia plateau-fibular axis angle. RESULTS: The study consisted of 24 (54.5 %) male and 20 (45.5 %) female patients. According to the proximal fibular inclination, 29 cases (65.9 %) were of the oblique type, and 15 cases (34.1 %) were of the horizontal type. The distribution of PTFJ variations was as follows: 17 (38.6 %) concave, 4 (9.1 %) convex, 7 (15.9 %) atypical, and 16 (36.4 %) flat type. Regarding the PTFJ joint contour, the distribution was 13 (29.5 %) type a, 11 (25 %) type b, and 20 (45.5 %) type c. There was no relationship between measurements of PITFJ morphology and the type of ankle fracture and/or syndesmosis injury (p > 0.05). CONCLUSION: PTFJ morphological features are not associated with rotational ankle fractures and syndesmotic ligament injuries.

An unusual cause of febrile knee pain in children: Septic arthritis of the proximal tibiofibular joint (a case report).

INTRODUCTION AND IMPORTANCE: Septic arthritis (SA), an infection affecting joints, is primarily attributed to bacteria, viruses, or fungi, with the hip, knee, and ankle being common sites of involvement. However, SA of the proximal tibiofibular joint is exceptionally rare. We report a highly uncommon case of lateral knee pain with fever in an 11-year-old boy caused by SA of the proximal tibiofibular joint. CASE PRESENTATION: The case involves an 11-year-old male admitted with atraumatic knee pain, fever, and limping. Physical examinations revealed no pain or tenderness of the knee joint, but a painful swelling near the proximal tibiofibular region. The patient had a temperature of 38.6 °C and a petechiae-like rash. Initial bloodwork showed an inflammatory syndrome, and blood cultures were negative. Imaging, including X-rays, ultrasound, and MRI, revealed a fusiform collection near the fibula and a 40*10 mm mass. Surgery, performed through a posterolateral approach, identified purulence in the tibiofibular joint. Bacteriological samples confirmed methicillin-sensitive Staphylococcus aureus, with histopathological results confirming non-specific septic synovial involvement. The patient received a six-week course of dual empirical antibiotics and showed afebrile status postoperatively. At the two-year follow-up, the patient walked independently with no restrictions in joint mobility. CLINICAL DISCUSSION: SA of the tibiofibular joint is rare but should be considered in febrile knee pain, especially if lateralized. CONCLUSIONS: A favorable outcome require a prompt diagnosis and treatment, involving surgical debridement, appropriate antibiotics, and postoperative immobilization.

The current trend of proximal tibiofibular ganglion cyst: A summary of 7 case series and 61 case reports.

Purpose: To review the different types of ganglion cysts surrounding the proximal tibio-fibular joint, their management options, outcomes, and recurrence. Design: Descriptive analytical review. Results: 7 case series consisting of a total of 159 patients and 61 case reports consisting of 80 patients (with three patients having bilateral pathology) were included in this review. (Total cysts 159 + 83 = 242). The mean age was 41 years, and 71 % of the patients were males. 96.5 % of the cases were managed operatively, out of which 98 % of patients felt improvement in local symptoms and 71.5 % had improvement in neurological symptoms. Complete excision of the cyst is the primary mode of operative management. Many added procedures with complete excision are to mitigate the risk of recurrence. The recurrence rate of aspiration, simple excision alone, simple excision with recurrent articular branch neurectomy, and simple excision with PTFJ procedures were 77 %, 56 %, 11.5 %, and 0 %, respectively. Outcomes beyond recurrence were poorly reported. Conclusion: There is not enough literature regarding the topic from which any formal systematic review can be done. Our summary suggests that aspiration alone or with steroid injection is associated with the highest recurrence rates among all the procedures. Complete excision with recurrent articular branch neurectomy should be the primary management. Revision cyst excision in isolation is an inadequate treatment option, therefore should be done in conjunction with PTFJ arthrodesis, which reduces the recurrence rates. Better quality studies are needed that report patient-centered outcomes and morbidities following PTFJ procedures.

Biomechanical Assessment of Bicortical Suspension Device Fixation for Proximal Tibiofibular Joint Instability: Single Versus Double Device.

BACKGROUND: Bicortical suspension device (BCSD) fixation treats proximal tibiofibular joint (PTFJ) instability in both the anterolateral and posteromedial directions. However, biomechanical data are lacking as to whether this technique restores the native stability and strength of the joint. PURPOSE: To test (1) if BCSD fixation restores the native stability and strength and (2) if using 2 devices is needed. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen pairs of fresh-frozen cadaveric specimens were obtained. Six pairs were assigned to the control group and 10 matched pairs assigned for transection to model PTFJ and subsequent BCSD fixation (one specimen with 1-device repair and the other with 2-device repair). Joint stability and strength were assessed by translating the fibular head relative to the fixed tibia either anterolaterally or posteromedially. Control specimens received 20 cycles of 0- to 2.5-mm joint displacement tests (subfailure) and then proceeded to load to failure (5 mm). For the experimental group, cyclic tests were repeated after ligament resection and after fixation. Forces and stiffness at 2.5- and 5-mm displacement were recorded for comparisons of joint strength and stability at subfailure and failure loads, respectively. RESULTS: After repair of anterolateral instability, both the single- and double-device fixations successfully restored near-native states, with no significant differences as compared with the intact group for forces at subfailure load (P = .410) or failure load (P = .397). Regarding posteromedial instability, single-device repair did not restore forces to the near-native state at subfailure load (intact: 92.9 N vs single: 37.4 N; P = .001) or failure load (intact: 170.7 N vs single: 70.4 N; P = .024). However, the double-device repair successfully restored near-native posteromedial forces at both subfailure load (P = .066) and failure load (P = .723). CONCLUSION: For treatment of the most common form of PTFJ instability (anterolateral), this cadaveric study suggests that 1 BCSD is sufficient to restore stability and strength. The current biomechanical results also suggest that 2 devices are needed for restoring PTFJ posteromedial stability and strength. Using 2 devices addresses both types of instability and provides more PTFJ posteromedial stability. CLINICAL RELEVANCE: The results suggest that 1 device should be used for treating anterolateral instability and 2 devices used for posteromedial instability based on the biomechanical study.

Neglected Proximal Tibiofibular Joint Dislocation Treated With a Cortical Button Suspension Device: A Case Report.

Proximal tibiofibular joint dislocation is a rare knee injury. Hence, its diagnosis is often missed. Herein, we have reported a case of posterior lateral proximal tibiofibular joint dislocation that was initially missed because it was associated with a fibula diaphyseal fracture. Our patient was a 23-year-old male with a complaint of left lateral knee pain and a history of fall from a motorcycle. He was treated with a cortical button suspension device. The patient reported no symptoms or complications at the one-year follow-up. Proximal tibiofibular joint dislocation is easily neglected if not considered as a diagnosis during clinical assessment. Half of these cases present with symptoms such as chronic pain and peroneal nerve palsy that require surgical treatment. A detailed physical examination and close review of imaging findings are important to establish a definitive diagnosis. A cortical bone button suspension device could be the appropriate treatment for cases requiring surgical management.

Morphology of the proximal tibiofibular joint and ligaments using three-dimensional computed tomography: A cadaveric study.

BACKGROUND: The aim of our study was to clarify the morphology of the proximal tibiofibular joint (PTFJ), insertion sites of the proximal tibiofibular ligaments (PTFLs), and related osseous landmarks on three-dimensional (3D) computed tomography (CT) images. METHODS: Cadaveric knees were evaluated by dissection and 3D CT imaging. The anterior PTFL (A-PTFL) and posterior PTFL (P-PTFL) were isolated, and their tibial and fibular insertion sites were identified. The morphology and location of insertion sites and their positional relationships with osseous structures were analyzed on 3D CT images. RESULTS: The A-PTFL comprised up to four bundles, and the P-PTFL comprised two bundles. The mean length of the A-PTFL and P-PTFL was 11.3 mm and 10.3 mm, respectively. On the tibial side of the PTFJ, bony prominences were present at the A-PTFL and P-PTFL insertion sites and were clearly identified as osseous landmarks in all knees. On the fibular side, the A-PTFL and P-PTFL insertion sites were at the edge of the triangular pyramid of the fibular head. The mean PTFJ area was 198.8 mm2, and the mean inclination angle between PTFJ and tibial plane was 38.4°. There was an inverse correlation between the PTFJ surface area and the inclination angle. CONCLUSION: The present study clearly identified PTFL insertion sites on the tibia and fibula and showed the relationships between these insertions and osseous landmarks. These data improve our understanding of the anatomy of PTFL insertions, which may assist surgeons in performing anatomical reconstruction.

Comparative fixation devices for preventing migration of the proximal tibiofibular joint during tibial lengthening: a tether versus screw fixation.

BACKGROUND: When lengthening the tibia segment using motorized internal lengthening nails (MILN), undesired distal migration of the proximal fibula segment is prevented by tibiofibular stabilization, traditionally using a screw. A tightened cortical suspensory fixation rope (tether) is an alternative option, but its appropriateness has never been studied. The primary outcome was comparing the amount of proximal fibular migration between patients who were stabilized with either a tether or a screw. The secondary outcome was to evaluate the effect of fibular migration on the clinical outcome between both groups. METHODS: A retrospective study was conducted on patients who underwent tibial lengthening with MILN between April 2016 and June 2022. Two cohorts were compared: 18 limbs with tether fixation versus 29 limbs with screw fixation. Data on the patient's age, sex, etiologies, and clinical outcomes were collected. Radiographic measurements included the lengthening distance and the amount of proximal fibular migration. RESULTS: In total, 47 limbs from 41 patients, with average age 35.01 ± 13.72 years old. There were 28 males (68.29%) and 13 females (31.71%). The tether group demonstrated a statistically significant greater distance of migration than the screw group (p < 0.001), with an average migration distance of 8.39 ± 5.09 mm and 2.59 ± 3.06 mm, respectively. No correlation was found between the amount of tibial lengthening and the distance of proximal fibular migration in both the tether group (p = 0.96) and the screw group (p = 0.32). There was no significant difference in the change of knee extension between both groups (p = 0.3), and no patients reported knee pain or tightness. CONCLUSION: A screw provides better resistance to proximal tibiofibular joint migration during MILN lengthening, but the difference appears clinically inconsequential. Either option appears suitable.

Proximal Tibiofibular Joint Ganglion Cyst: A Rare Cause of Calf Pain.

Intramuscular cysts are rare at the proximal calf. However, their etiology is varied, making accurate diagnosis and treatment really difficult. Ganglion cyst (GC) of the proximal tibiofibular (PTF) joint is a very rare entity with an estimated prevalence of 0.76%. Intramuscular extension of the GC arising from the PTF joint is an even rarer lesion, and only a few cases have been published in the literature. Hereby, we report an infrequent case of a GC arising from the PTF joint with a sizable pedicle and intramuscular (lateral head of gastrocnemius) extension to the posterolateral aspect of the right calf.

Proximal Tibiofibular Joint Dysfunction as a Cause of Persistent Knee Pain After Total Knee Arthroplasty: A Case Series and Literature Review.

Total knee arthroplasty (TKA) is a common procedure for end-stage osteoarthritis of the tibiofemoral and patellafemoral joints. Despite a good outcome in many patients, persistent knee pain after TKA poses a significant challenge. Proximal tibiofibular joint (PTFJ) osteoarthritis has been seen as a rare cause of such pain. In this case series, we share our experience diagnosing PTFJ dysfunction and managing it with intra-articular ultrasound-guided injections. We demonstrate that PTFJ arthropathy may be a more common cause of chronic post-TKA pain than generally believed.

Management and outcomes of proximal tibiofibular joint ganglion cysts: A systematic review.

BACKGROUND: Proximal tibiofibular joint (PTFJ) ganglion cysts are rare; however, their optimal management remains unclear. This study aimed to systematically review the surgical treatment options with a focus on recurrence rates and complications. METHODS: A systematic review of the literature was performed, searching three electronic databases, according to the PRISMA guidelines. The presentation, treatment, and outcomes of PTFJ ganglion cysts of minimum 1-year follow-up was collected. Study quality was assessed using the Modified Downs and Blacks checklist. Surgical interventions were considered ordinally from simple to more extensive as follows; cyst aspiration, cyst excision, cyst excision with an intervention to the PTFJ, either a hemi-resection or arthrodesis. RESULTS: Twenty-two studies comprising 100 patients (101 knees) met inclusion criteria. Among all patients, pain was present in 59.7%, a lateral fullness in 71.6% and symptoms of the common peroneal nerve in 57.4%. The overall rate of recurrence after primary treatment was 28.9%. Recurrence rates for aspiration, cyst excision, PTFJ hemi-resection and PTFJ arthrodesis were 81.8%, 27.4%, 8.3% and 0%, respectively. Revision excision for recurrence failed in all cases. Outcomes beyond recurrence were poorly reported. CONCLUSION: Addressing the PTFJ at the time of cyst excision reduces recurrence rates, however, the morbidity from PTFJ hemi-resection and arthrodesis are poorly reported. Whilst primary excision offers resolution in most cases (73%), revision cyst excision in isolation for the treatment of recurrent cysts is an inadequate treatment option. Cyst aspiration is ineffective. Data pertaining to patient reported outcomes for all treatment types are lacking.

Role of the proximal tibiofibular joint on the biomechanics of the knee joint: A three-dimensional finite element analysis.

PURPOSE: The proximal tibiofibular joint (PTFJ) is easily ignored, although many diseases of the knee are caused by PTFJ injuries. Therefore, studying PTFJ biomechanics is very important. The effects of PTFJ injury on ankle function have been reported. However, few studies have assessed the effects of PTFJ injury on the knee joint. This study was performed to describe the biomechanical effects of PTFJ on the knee joint according to a three-dimensional finite element model. METHODS: The knee joint of a healthy volunteer was scanned by CT and MRI. CT and MRI scanning data in DICOM format were imported into Mimics software. Subsequently, 3D models of the normal and PTFJ injured knee, including the bone, cartilage, meniscus and ligament structures were established, and their validity was verified on the basis of available studies in literature. The biomechanical changes in the two knee models under different conditions were compared. RESULTS: The validity of the intact model was verified. No significant difference was observed in tibial mobility in the two models under the conditions of 134 N forward, 10 N·m internal rotation and 10 N·m valgus load. After application of 134 N backward, 10 N·m varus and external rotation load with respect to the tibia, the posterior movement of the tibia and the varus and external rotation angles of the tibia were 3.583±0.892 mm, 4.799±0.092° and 18.963±0.027° in the normal knee model, and 5.127±1.224 mm, 5.277±0.104° and 21.399±0.031° in the PTFJ injury model, respectively, and a significant statistical difference was observed. CONCLUSIONS: PTFJ played an important role in maintaining the posterolateral stability of the knee joint and thus deserves more attention in clinical operations.

The effect of proximal tibiofibular joint dislocation on knee mechanics: reduction and fixation matters.

PURPOSE: Proximal tibiofibular joint (PTFJ) dislocations are under-investigated injuries. There is scant basic science or clinical evidence to direct management. The purpose of this study was twofold; first to investigate the pathomechanics of PTFJ dislocation on knee mechanics. The second purpose was to evaluate knee mechanics following reduction and fixation. METHODS: Six cadaveric legs were tested on a mechanical platform. A 5 Nm external rotation force was applied to each knee and the external rotation and fibular translation was measured for several study conditions at 0°, 30°, and 90° of flexion. Conditions included: the native state, transection of the posterior PTFJ ligament, transection of the anterior and posterior ligaments, screw fixation, and suspensory fixation. Screw fixation was performed using a single quadricortical 3.5 mm screw. Suspensory fixation was performed using an Arthrex TightRope device RESULTS: Transection of the anterior and posterior ligaments increased external rotation by 4.3°, 5.9°, and 5.6°, at 0°, 30°, and 90° (p ≤ 0.001), respectively. Screw and suspensory fixation returned external rotation to a near native state with mild overconstraint. Complete transection of anterior and posterior ligaments resulted in pathologic anterior fibular translation of 1.51 mm (p = 0.001), 1 mm, (p = 0.02) and 0.44 mm (p = 0.69) for 0°, 30°, 90° of knee flexion. Screw and suspensory fixation restored native translation at all points with a small degree of overconstraint. CONCLUSION: Disruption of the PTFJ causes pathologic external rotation and anterior fibular translation. Fixation restores near native motion with minor overconstraint. Surgeons should consider reduction and fixation of PTFJ injuries to restore native knee mechanics.

Ultrasound examination of tibiofibular widening of forceful knee flexion is recommended for patients with proximal tibiofibular joint instability.

BACKGROUND: Proximal tibiofibular joint (PTFJ) instability is uncommon, resulting from violent twisting motions of the flexed knee during sport activities. No known image variables functionally relate the degrees of PTFJ instability. OBJECTIVE: This study used ultrasound imaging to quantify the discrimination threshold for PTFJ instability and relevant functional significances. METHODS: Twenty patients (mean age: 42.7 (21-59) years) with chronic PTFJ instability participated in this study. Along with the Knee Injury and Osteoarthritis Outcome Score (KOOS),the tibiofibular distances of the affected and unaffected knees were estimated with ultrasonography in the four standardized conditions at 90° of flexion of the hip and knee, including neutrally relaxed position, passive internal rotation, passive external rotation, and forceful flexion of the knee joint. RESULTS: During forceful knee flexion, the absolute tibiofibular distance in the affected leg (28.1 ± 4.0 mm) was greater than the unaffected leg (25.1 ± 3.7 mm). Relative changes in tibiofibular distance (RTFD) were different for both legs (affected leg:3.9 ± 2.7 mm; unaffected leg:1.0 ± 1.4 mm) (P < 0.001). The area under the receiver operator characteristic curve for the RTFD was a potent predictor of PTFJ instability (84.5%) with specificity of 95% and sensitivity of 65%. Patients with RTFD greater than 2.95 mm exhibited higher scores on the KOOS subscales of pain (P = 0.043) and quality of life (P = 0.009). CONCLUSION: Ultrasonic measurement of the tibiofibular distance under forceful knee flexion is clinically valuable for diagnosing PTFJ instability with functional significance.

Association between the inclination angle of the proximal tibiofibular joint surface and medial compartment knee osteoarthritis.

BACKGROUND: Fibular support for the lateral tibial plateau through the proximal tibiofibular joint (PTFJ) results in nonuniform settlement of the tibial plateau in middle-aged and elderly persons and may lead to medial compartment knee osteoarthritis. However, the inclination angle of the PTFJ surface varies widely and may affect nonuniform settlement. The purpose of this case-control study was to assess the association between the inclination angle of the PTFJ surface and medial compartment knee osteoarthritis. METHODS: The fibular inclination angle (FIA) and tibial inclination angle (TIA) of the PTFJ surface were measured using radiographs. Differences of FIA and TIA among groups were assessed with t tests and the odds ratios (ORs) for risk factors of medial compartment knee osteoarthritis were calculated with binary logistic regression analysis. RESULTS: Forty patients and 40 control participants were included in this case-control study. Patients had both a lower FIA (P=0.005) and TIA (P=0.000) than the controls, and logistic regression analysis showed that FIA (OR =7.000) and TIA (OR =17.000) were risk factors for medial compartment knee osteoarthritis. CONCLUSIONS: A lower inclination angle of the PTFJ surface is associated with a risk of medial compartment knee osteoarthritis. Clinically, early prevention of medial compartment knee osteoarthritis should be considered for middle-aged and elderly persons with low PTFJ inclination angles.

Proximal Tibiofibular Joint: A Forgotten Entity in Multi-Ligament Injuries of the Knee.

PURPOSE: The proximal tibiofibular joint (PTJF) can be injured with the structures in the lateral aspect of the knee in a multi-ligament knee injury (MLKI) patient. Such injuries are scarce but require attention in the management of the complex MLKIs. The assessment and management of such injuries are not well described in the English literature. This study describes the frequency of PTFJ injuries, clinical assessment and functional outcomes of such injuries in MLKI patients. METHODOLOGY: The data were collected retrospectively from the cohort from 2013 to 2018. The 84 MLKI were included in the study, out of which 9 patients had associated PTFJ injury. All the PTFJ injuries were operated by one single surgeon (D.S) which involves stabilization with K-wires (Kirschner wire) and fixation with 4 mm cancellous cannulated screw along with reconstruction surgery for MLKI in single stage. RESULTS: The frequency of PTFJ injury in our patient cohort is 10.71%. Three patients out of the nine patients received Larson procedure apart from the fixation of PTFJ. At a mean follow-up of 13 months, the Lysholm score was 77.4 (range: 69-86) and mean modified Cincinnati score was 62 (range: 52-72). There was grade I posterior laxity present in one patient with PCL and PLC injury, one patient with ACL, PCL and PLC injury, and one patient with ACL, PCL, MCL and PLC injury at final follow-up. Terminal flexion of 15° or more restriction was noted in six patients. All patients were satisfied with the outcome. CONCLUSION: Evaluation of PTFJ should be an integral part of preoperative as well as an intraoperative examination of MLKI patients. The fixation of this joint is of utmost importance for the reconstructive ligament procedures on the lateral aspect of the knee. The dial test used for the assessment of the integrity of PLC injury should have a prerequisite of proximal tibiofibular joint stability, otherwise, it can lead to erroneous assessment. LEVEL OF EVIDENCE: IV.

Complete posterior dislocation of fractured lateral condyle of tibia with disruption of proximal tibiofibular joint: Technical note.

Tibial plateau fracture-dislocations are relatively uncommon injuries. They represent instability patterns due to injured collateral ligaments or extensive condylar depression. Medial and lateral subluxations of the fractured fragments represent the majority of these injuries. Posterior dislocations with the tibial plateau fractures are extremely rare injuries. Moreover, isolated posterior dislocations of the tibial condyles with a normally maintained position of the remaining tibia have not been reported in literature. We describe a difficult case scenario in which whole of the articular segment of the lateral condyle of the tibia was separated from its anterolateral rim and completely dislocated posteriorly, with no contact with the lateral condyle of the femur. Besides this, there was a complete disruption of the proximal tibiofibular joint as well. To further add to the problem, the distal pulses in the affected limb had a reduced volume. Stepwise management of all aspects of this injury has been described in this technical note along with a six-month follow-up.

Predictive value of the morphology of proximal tibiofibular joint for total knee replacement in patients with knee osteoarthritis.

The association between proximal tibiofibular joint (PTFJ) and knee osteoarthritis (OA) has been understudied. The objective of this study was to determine whether the morphology of PTFJ has predictive value for the risk of total knee replacement (TKR). Case knees from Osteoarthritis Initiative participants with TKR at 24-60 months follow up (cases) were 1:1 matched with control knees (no TKR throughout 60 months) by baseline age, sex, and Kellgren-Lawrence grade. PTFJ morphological parameters, including coronal inclination angle (angle α), sagittal inclination angle (angle ß), fibular contacting area (S), load-bearing area (Sτ), lateral stress-bolstering area (Sφ), and posterior stress-bolstering area (Sυ) were assessed using coronal and sagittal magnetic resonance imaging (MRI), respectively. Associations of the morphological measures at baseline and the time point before TKR (T0 ) and their changes with TKR risks were examined using conditional logistic regression analyses. Two hundred and twenty-three knees of 193 participants received TKR between 12 and 60 months and therefore were matched with 223 control knees. Of these, 173 paired knees had MRI readings available both at baseline and T0 time point. While baseline angle α was positively associated with TKR risk, other measures at baseline and all measures at T0 were not significantly associated with TKR risk. Changes in S, Sτ, and Sυ were significantly and negatively associated with the risk of TKR (ΔS, odds ratio [OR] = 0.38, 95% confidence interval [CI]: 0.19-0.76; ΔSτ, OR = 0.37, 95% CI: 0.16-0.87; ΔSυ, OR = 0.22, 95% CI: 0.08-0.62, respectively). This data shows that morphological changes of PTFJ predict the risk of TKR, suggesting PTFJ may play a role in knee OA.

The articular branch of the peroneal nerve to the proximal tibiofibular joint descends at a mean height of approximately 18 mm distal to the postero-lateral tip of the fibular head.

PURPOSE: The aim of the study was to evaluate the anatomical details of the articular branch of the peroneal nerve to the proximal tibiofibular joint and to project the height of its descent in relation to the fibular length. METHODS: Twenty-five lower extremities were included in the study. Following identification of the common peroneal nerve, its course was traced to its division into the deep and superficial peroneal nerve. The articular branch was identified. The postero-lateral tip of the fibular head was marked and the interval from this landmark to the diversion of the articular branch was measured. The length of the fibula, as the interval between the postero-lateral tip of the fibular head and the tip of the lateral malleolus, was evaluated. The quotient of descending point of the articular branch in relation to the individual fibular length was calculated. RESULTS: The articular branch descended either from the common peroneal nerve or the deep peroneal nerve. The descending point was located at a mean height of 18.1 mm distal to the postero-lateral tip of the fibular head. Concerning the relation to the fibular length, this was at a mean of 5.1%, starting from the same reference point. CONCLUSION: The articular branch of the common peroneal nerve was located at a mean height of 18.1 mm distal to the the postero-lateral tip of the fibular head, respectively, at a mean of 5.1% of the whole fibular length starting from the same reference point. These details represent a convenient orientation during surgical treatment of intraneural ganglia of the common peroneal nerve, which may result directly from knee trauma and indirectly from ankle sprain.

Proximal tibiofibular joint changes after closed-wedge high tibial osteotomy. Are they relevant?

BACKGROUND: There is some controversy about how the proximal tibiofibular joint (PTFJ) capsulotomy changes PTFJ anatomy in closed-wedge high tibial osteotomy (CW-HTO) and about how this affects ankle and knee mobility and the onset of lateral knee pain. The aim of this study is to evaluate changes in PTFJ after CW-HTO, and its possible clinical significance. METHODS: This study includes 50 patients who underwent CW-HTO with tibiofibular capsulotomy from 2000 to 2018 in our hospital. A clinical evaluation was conducted to evaluate pain location. The degrees of osteoarthritis and the proximal fibular subluxation were evaluated on radiographs. A dynamic analysis of the PTFJ was also performed comparing proximal fibular head subluxation on anteroposterior knee radiographs with the ankle placed in neutral position and dorsiflexed. RESULTS: The clinical evaluation revealed that two patients had a sore scar, five had pain on the PTFJ with manual compression, and none referred lateral compartment pain. The radiological analysis revealed an average proximal subluxation of the fibular head after the osteotomy of 9.64 (range: 0-29) mm, which was greater in oblique PTFJ (p < 0.05). After the surgery, all the patients developed some degree of PTFJ arthritis. There was no correlation between lateral pain and proximal fibular subluxation, tibiofibular arthritis, or lateral compartment arthritis. The dynamic analysis revealed no significant changes. CONCLUSIONS: After CW-HTO all the patients developed proximal subluxation of the fibular head and a variable degree of PTFJ osteoarthritis, but these changes seem to be unrelated with lateral knee pain.