Internal rotational patellar resection and patella alta induced patellar maltracking in total knee arthroplasty: intraoperative measurement of the patellofemoral pressure.

BACKGROUND: Anterior knee pain due to patellar maltracking following total knee arthroplasty (TKA) reduces patients' satisfaction. This study aimed to determine the patellofemoral pressure (PFP) in patients with favorable patellar tracking (FT) and impaired patellar tracking (IT) following TKA, the factors causing patellar maltracking, and the effect of lateral retinacular release (LRR) on patients with IT. METHODS: Forty-four patients with varus knee osteoarthritis undergoing cruciate-retaining TKA were enrolled. After component implantation, patients with a separation of ≥ 2 mm of the patellar medial facet from the medial femoral trochlea throughout knee range of motion were classified into the IT group; meanwhile, the others were classified into the FT group. PFP was measured intraoperatively in three phases: (1) with the resurfaced patella (RP); (2) with the resurfaced patella and knee (RPK); and (3) when LRR was performed in IT (post-LRR). The PFPs at 0°, 90°, 120°, and 135° knee flexion were compared between FT and IT using the Mann-Whitney U test. Pairwise comparison of the PFP in IT between RPK and post-LRR was performed using the Wilcoxon signed-rank test. Correlations between PFP and pre- and postoperative radiographic parameters, such as hip-knee-ankle angle, lateral distal femoral angle, medial proximal tibial angle, anterior femoral offset, Insall-Salvati ratio (ISR), patellar tilt, and patellar resection angle (PRA), were evaluated using Spearman's rank correlation coefficients. RESULTS: High lateral PFP in the knee flexion position led to patellar maltracking. Patients with IT (n = 24) had higher lateral and lower medial PFP than did patients with FT (n = 20) at 90°, 120°, and 135° knee flexion in RP and RPK. LRR in IT reduced the lateral PFP in the knee flexion position. PRA and ISR were correlated with the lateral PFP at no less than 90° in RP and RPK. CONCLUSIONS: This study demonstrated that internal rotational patellar resection, which resulted in a thick medial patellar remnant and a thin lateral counterpart, and patella alta were the causative factors of high lateral PFP, which induced patellar maltracking after TKA. Surgeons should avoid internal rotational patellar resection to achieve FT and perform LRR in patients with patellar maltracking.

Difficulty in Early Diagnosis of Bilateral Posterior Fracture-dislocation of the Shoulder Caused by an Electric Shock in a Walk-in Patient: A Case Report.

Introduction: Bilateral posterior fracture-dislocation of the shoulder is a very rare injury that is commonly missed. Almost 70% of bilateral posterior dislocations are due to convulsive seizures, with electric shocks accounting for < 5% of bilateral posterior shoulder dislocations. Case Report: The case of a walk-in patient, a 52-year-old man, with bilateral posterior fracture-dislocation of the shoulder caused by an electric shock is reported. Although he was initially admitted to the emergency department for observation of the potential complications of an electric shock, such as fatal arrhythmia and rhabdomyolysis, he subsequently consulted an orthopedic surgeon 4 days after the event due to persistent bilateral shoulder pain and was diagnosed using X-ray and computed tomography with bilateral posterior fracture-dislocation of the shoulder. Following open reduction and internal fixation 7 days after the injury, the upper limbs were fixed with shoulder braces at a slightly flexed and abducted position with neutral rotation for 3 weeks postoperatively followed by range of motion exercises. Twelve months after surgery, he had a Constant shoulder score of 94, an American Shoulder and Elbow Surgeon score of 100, and no shoulder re-dislocation or humeral head necrosis. Conclusion: In this walk-in patient, the diagnosis of bilateral posterior fracture-dislocation of the shoulder caused by an electric shock was delayed. We believe that understanding the mechanism of this type of injury will facilitate its early diagnosis.

Nontuberculous mycobacteriosis oligoarthritis of the right hand misdiagnosed as rheumatoid arthritis: A case report.

Infection with Mycobacterium marinum has several different clinical presentations. Most commonly, it appears as a solitary papulonodular lesion on an extremity. A rare presentation of osteoarticular M. marinum involving multiple small joints and tenosynovitis of the hand, which was misdiagnosed as rheumatoid arthritis, is reported. The patient was initially treated for seronegative rheumatoid arthritis but failed to respond to methotrexate. Magnetic resonance imaging showed arthritis and tenosynovitis. Subsequently, synovial biopsy led to histological and microbiological diagnosis. Antimycobacterial treatment should be started promptly in such cases. The combined use of rifampicin, ethambutol, and clarithromycin appears to be effective, and debridement is indicated in patients with deep-seated infections.