Fabella Syndrome and Common Peroneal Neuropathy following Total Knee Arthroplasty

Case. A 62-year-old man presented with persistent lateral knee pain 15 months following an uncomplicated total knee arthroplasty. There was a tendinous snapping structure over the lateral aspect of the knee in deep flexion with positive Tinel’s sign over the fibular head. The patient underwent an uncomplicated flabella excision. The patient was cleared to return to work and full duty at two months postoperatively. Conclusion. Flabella syndrome is a rare but increasingly common mechanism of persistent lateral knee pain following total knee arthroplasty. Surgeons should be aware of this etiology of persistent lateral knee pain and offer treatment modalities to address this pathology.

Patella dislocation with unusual osteochondral fracture, whilst playing virtual reality game

Case: We present case of a 37-year old male who sustained Patella dislocation with an unusual osteochondral fracture (OCF) involving the posterolateral femoral condyle, whilst playing a virtual game, wearing virtual game headset with goggles. He was treated conservatively for patella dislocation and had the OCF treated surgically. At 18 months follow up, his patella was stable and the OCF had healed. Conclusion: OCF of posterolateral femur following patella dislocation is unusual. It must be suspected in patients who sustain patella dislocation whilst doing deep flexion maneuvers. Patella dislocation can conceal an unusual OCF.

Evaluation of Knee Kinematics and Moments during Active Deep Flexion Activity after Oxford Mobile-Bearing Medial UKA—A Two-Year Follow-Up Study

Few studies have assessed knee range of motion (ROM) and moments of patients with mobile-bearing unicompartmental knee arthroplasty (MB UKA) during active deep flexion activities. We analyze knee kinematic and kinetic parameters during postoperative squatting-standing activity, aiming to evaluate the efficacy of MB UKA and postoperative rehabilitation progress. This was a clinical cohort study. We followed up with 37 patients diagnosed with medial knee osteoarthritis (OA) with primary UKA. After screening 31 patients were recruited to take gait tests. Squatting-standing activities were performed under the test of 10-camera motion analysis system and force plates preoperatively at different stages after UKA (12, 18, and 24 months). The average duration of follow-up was 24.4 months (from 22.8 to 26.7 months). Hip-knee-ankle angle improved significantly compared with pre-UKA as well as scores of American Knee Society Score, numeric rating scale, ORS, and Western Ontario and McMasters. University Osteoarthritis Index. About 83.6% (31/37) of follow-up patients completed squatting-standing activity independently. At 1-year follow-up, peak varus angle (20.6 ± 2.8 degrees), internal rotation angle (13.6 ± 1.8 degrees), extensor moment (1.44 ± 0.04N*m/kg), and internal rotator moment (0.02 ± 0.005N*m/kg) of UKA knees were inferior to contralateral knees. Peak adductor moment (0.76 ± 0.05N*m/kg) was superior to contralateral knees. At 2-year follow-up, peak flexion angle (125.0 ± 2.8 degrees) showed a growing trend meanwhile extensor (1.70 ± 0.03N*m/kg) and adductor (0.68 ± 0.06 N*m/kg) moment closely resembled those of the contralateral knee. MB UKA could alleviate the affected knee mainly in flexion-extension ROM and moment meanwhile did not affect the biomechanical indicators of healthy limbs. OA knees in the early postoperative period showed decreased extensor moment and increased adductor moment during active deep flexion activity. Better ROM and relatively more natural extensor and adductor moment of UKA knee with rehabilitation time increasing may predict ideal rehabilitation outcome in the medium or longer term.

Length Change Pattern of the Medial Structures of the Knee and Related Reconstructions

Aims and Objectives: Chronic medial instability presents a severe problem both for the patient and the surgeon, and may result into anterior cruciate ligament graft failure in a combined anteromedial instability. Thus, reconstructions have been developed to conquer this problem. However, these are not capable of mimicking the flat anatomy of the medial structures of the knee. The goal of the present study was to examine the length change patterns of the native medial structures of the knee and their related reconstructions. It was hypothesised that the different portions of the medial collateral ligament present different length change patterns, which cannot be imitated by current reconstructions. Materials and Methods: Eight cadaveric knees were dissected of skin and subcutaneous fat. The satorius fascia was removed to get a clear vision of the medial structures. The knee was then mounted in a rig and the quadriceps muscle and the iliotibial tract were loaded, using cables and hanging weights, according to its fiber orientations and cross-sections. Threads attached to three tibial pins at the anterior/middle/posterior portion of the medial collateral ligament (MCL) were then guided to three femoral eyelets at the anterior/middle/posterior portion of the femoral MCL insertion and analogous with the tibial/femoral posterior oblique ligament (POL) insertion. A tibial pin was also put at the semitendinosus insertion to imitate the Lind reconstruction. Between 0-120 degree knee flexion, the distances between each possible tibiofemoral combination were measured using a linea variable differential transformer (LVDT). Statistical analysis was performed using two way repeated measurements ANOVA. Results: The anterior MCL showed an initial slackening (2%) until 20° flexion, followed by a tightening (5%) towards deep flexion (120°), meaning that it is tight in flexion. The posterior MCL also showed an initial slackening (4%) until 20° of flexion. However, then followed by an isometric area (20-80°) and a further slackening (8%) towards deep flexion (120°), meaning that it is tight in extension. The three portions of the POL showed a linear slackening between 0-120° (25%). The middle MCL showed a sine wave behaviour, slackening from 0- 60° (3%) and tightening between 60-100° (1%). This behaviour was similar in the Lind and Robinson reconstruction, which were the most isometric tibiofemoral combinations (total strain range: 5,3 ± 2,1). The native POL length changes showed the most non-isometric behaviour resulting into a total strain range of 28,8 ± 6,2, which was significantly different from the native MCL and MCL reconstructions (p< .001) Conclusion: The anterior, middle, and posterior parts of the MCL showed different length change patterns. The anterior part tightened in flexion, whereas the posterior part tightened in extension. This behavior could not be reproduced by the current reconstructions, such as the Lind and Robinson procedure, which only could imitate the middle portion of the native MCL.

The Federated Practice of Soccer Influences Hamstring Flexibility in Healthy Adolescents: Role of Age and Weight Status

The aim of this study was to compare the hamstring flexibility between federated soccer and non-federated adolescents, and also to evaluate the effect of age and weight status on hamstring flexibility. The participants were 234 students (11–18 years old) divided into: (i) G1: non-federated (n = 127), and (ii) G2: federated in soccer (n = 107). The deep flexion of the trunk (DF) test and the sit and reach test (SRT) were performed. G2 showed higher values for the DF and SRT compared to G1 (p < 0.05). Both flexibility tests correlated positively (r = 0.4, p < 0.001). Body mass index (BMI) was negatively correlated with the DF test (r = −0.3, p < 0.001), but not with the SRT. Divided by BMI, the underweight and normal weight groups had higher scores in the DF test compared with the overweight and obese groups (p < 0.001). BMI was negatively correlated with hamstring flexibility. Federated soccer students present higher scores of hamstring flexibility.