Jean Michel Laffosse

Evaluation of the accuracy of patient-specific cutting blocks for total knee arthroplasty: a meta-analysis

PurposeBecause published studies on the accuracy achieved with patient-specific guides during total knee arthroplasty (TKA) contradict each other, this systematic review and meta-analysis sought to compare radiological TKA outcomes when patient-specific cutting blocks (PSCB) were used to the outcomes when standard manual instrumentation was used.MethodsThe meta-analysis was implemented according to PRISMA Statement Criteria. The primary endpoint was the hip-knee-ankle (HKA) angle, which represents the leg’s mechanical axis. The accuracy of component placement in the coronal and sagittal planes, and the accuracy of femoral component rotation were also compiled. After testing for publication bias and heterogeneity across studies, data were aggregated random-effects modeling when necessary.ResultsFifteen articles were included: 916 total knee arthroplasty cases in the PSCB group and 998 in the MI group. The mechanical axis did not differ between the two groups (weighted mean difference 0.07°; 95xa0% CI, -0.5° to 0.65°; pu2009=u20090.8). Risk ratio analysis revealed no protective effect of using PSCB relative to the appearance of HKA angle outliers (RRu2009=u20090.88; 95xa0% CI, 0.68–1.13; pu2009=u20090.3). There was a trend towards a protective effect with PSCB for the risk of femoral component outliers, but the opposite was observed for the tibial component. The implantation procedure was stopped in 30 cases because the surgeon-authors found excessive discrepancies between the intra-operative observations and the pre-operative plan.ConclusionsThis meta-analysis found no evidence that using patient-specific cutting blocks provides superior accuracy to using manual instrumentation during TKA.

Cadaveric study comparing the biomechanical properties of grafts used for knee anterolateral ligament reconstruction

PURPOSEnTo measure the biomechanical properties (maximum load, stiffness, and elongation) of the anterolateral ligament (ALL), gracilis, and iliotibial band (ITB) within the same subject.nnnMETHODSnThirteen unpaired knees were used (7 women, 6 men). The donors had a mean age at death of 54xa0years (range: 37 to 70xa0years). The mechanical properties of two types of ALL grafts were evaluated: ITB and two-strand gracilis. The mechanical properties of ALL were also measured. Validated methods were used to perform the tensile tests to failure and to record the results. Students t-test was used to compare the various samples.nnnRESULTSnThe maximum load to failure was 141xa0N (±40.6) for the ALL, 200.7xa0N (±48.7) for the gracilis, and 161.1xa0N (±27.1) for the ITB. Only the gracilis had a significantly higher failure load than ITB and ALL (Pxa0= .001 and Pxa0= .03). The stiffness was 21xa0Nxa0mm-1 (±8.2) for the ALL, 131.7xa0Nxa0mm-1 (±43.7) for the gracilis, and 39.9xa0Nxa0mm-1 (±6) for the ITB. The elongation at failure was 6.2xa0mm (±3.2) for the ALL, 19.9xa0mm (±6.5) for the gracilis, and 20.8xa0mm (±14.7) for the ITB.nnnCONCLUSIONSnThe gracilis had the highest maximum load to failure. The ITBs mechanical properties most closely resemble those of the ALL.nnnCLINICAL RELEVANCEnThe biomechanical properties of each potential ALL graft can be factored in when deciding which type of graft to use.

Can the gracilis replace the anterior cruciate ligament in the knee? A biomechanical study

PurposeThe purpose of this study was to determine whether a four-strand gracilis-only construct possesses the biomechanical properties needed to act as an anterior cruciate ligament (ACL) reconstruction graft.MethodsThis was a pilot study with 32 cadaver specimens. The biomechanical properties of three types of grafts were determined using validated tensile testing methods: patellar tendon (BTB), both hamstring tendons together (GST4) and gracilis alone (G4).ResultsThe maximum load at failure of the G4 was 416.4xa0N (±187.7). The GST4 and BTB had a maximum load at failure of 473.5xa0N (±176.9) and 413.3xa0N (±120.4), respectively. The three groups had similar mean maximum load and stiffness values. The patellar tendon had significantly less elongation at failure than the other two graft types.ConclusionsThe biomechanical properties of a four-strand gracilis construct are comparable to the ones of standard grafts. This type of graft would be useful in the reconstruction of the anteromedial bundle in patients with partial ACL ruptures.

Response to Jie et al.: How to explain the evaluation of the accuracy of patient-specific cutting blocks for total knee arthroplasty?

Dear Editor, We read with great interest the letter to the Editor entitled “How to explain the evaluation of the accuracy of patientspecific cutting blocks for total knee arthroplasty?” by Jie et al. [1] that was published in the December 2014 issue of International Orthopaedics. This letter was a comment on our recently published article entitled “Evaluation of the accuracy of patient-specific cutting blocks for total knee arthroplasty: a meta-analysis” [2]. Wewere very surprised to come across this letter to the Editor whilst we were doing additional research on the topic of patientspecific cutting blocks, a subject that we feel strongly about. As the authors of the original article in question, we would like to have been informed of these remarks so as to exercise our right to respond immediately in the same issue of the journal. In addition, there was no indication in the title that comments were being made specifically on our article, as is typically done.

Análisis estadístico de los factores que aumentan el sangrado perioperatorio en las fracturas trocantereas

OBJECTIVEnThe objective of this study was to determine the major risk factors for bleeding in patients with a pertrochanteric fracture in order to plan the transfusion strategy and to overcome the problem of post-surgical anaemia. Various factors were analysed, including the taking of anticoagulant and/or anti-platelet treatment, the type of fracture, type of anaesthesia, and the type of osteosynthesis used.nnnMATERIAL AND METHODSnA retrospective study was performed on 307 patients over 75 years old, operated on between the years 2005 and 2009.nnnRESULTSnBleeding was less in simple, non-comminuted fractures, in patients operated on using a mini-invasive screw-plate, in women, and in patients who did not take any anticoagulant or antiplatelet treatment.The only statistically independent factor associated with bleeding was fracture comminution.nnnDISCUSSIONnIn this study we have seen that patients operated on using a Gamma(®) and DHS(®) nail are transfused more than in those operated on using PPCP(®) and Traumax(®) plate. Evans fractures 1 or 2, A 2.2, or A 2.3, cervical-trochanteric or simple pertrochanteric fractures bled less than Evans 4 or 5, the rest of the type AO fractures, and the complex pertrochanteric fractures.nnnCONCLUSIONSnThe precise analysis of the type of fracture is important, particularly in older and fragile patients, to be able to anticipate the need for transfusion. Thus useless and costly, and sometimes dangerous transfusions may be avoided.