Aims

Mechanical impingement of the iliopsoas (IP) tendon accounts for 2% to 6% of persistent postoperative pain after total hip arthroplasty (THA). The most common initiator is anterior acetabular component protrusion, where the anterior margin is not covered by anterior acetabular wall. A CT scan can be used to identify and measure this overhang; however, no threshold exists for determining symptomatic anterior IP impingement due to overhang. A case-control study was conducted in which CT scan measurements were used to define a threshold that differentiates patients with IP impingement from asymptomatic patients after THA.

Mechanical irritation or impingement of the iliopsoas tendon accounts for 2–6% of persistent postoperative pain cases after total hip arthroplasty (THA). The most common trigger is anterior cup overhang. CT-scan can be used to identify and measure this overhang; however, no threshold exists for symptomatic anterior iliopsoas impingement. We conducted a case–control study in which CT-scan was used to define a threshold that differentiates patients with iliopsoas impingement from asymptomatic patients after THA.

We analyzed the CT-scans of 622 patients (758 CT-scans) between 2011 and 2020. Out of this population we identified 136 patients with symptoms suggestive of iliopsoas impingement. Among them, 6 were subsequently excluded: three because the diagnosis was reestablished intra-operatively (one metallosis, two anterior instability related to posterior prosthetic impingement) and three because they had another obvious cause of impingement (one protruding screw, one protruding cement plug, one stem collar), leaving 130 patients in the study (impingement) group. They were matched to a control group of 138 patients who were asymptomatic after THA. The anterior cup overhang (anterior margin of cup not covered by anterior wall) was measured by an observer (without knowledge of the clinical status) on an axial CT slice based on anatomical landmarks (orthogonal to pelvic axis).

The impingement group had a median overhang of 8 mm [IQR: 5 to 11] versus 0 mm [IQR: 0 to 4] for the control group (p<.001). Using ROC curves, an overhang threshold of 4 mm was best correlated with a diagnosis of impingement (sensitivity 79%, specificity 85%, PPV = 75%, NPV = 85%).

Pain after THA related to iliopsoas impingement can be reasonably linked to acetabular overhang if it exceeds 4 mm on a CT scan. Below this threshold, it seems logical to look for another cause of iliopsoas irritation or another reason for the pain after THA before concluding impingement is present.

Fasciae represent a very interesting source of thin, well vascularized soft tissue, which allows gliding of the underlying tendons, especially for coverage of particular anatomical zones, such as the dorsal aspect of the hand and fingers. Some fasciae (such as the fascia temporalis free fiap) have already been used in this way as free fiaps for the coverage of the extremities. The aim of this study was to investigate the blood supply of the posterior brachial fascia (PBF), in order to precise the anatomical bases of a new free fascial fiap.

Our study was based on dissections of 18 cadaveric specimens from 10 formalin preserved corpses. Six upper limbs were used to fictively harvest this fiap

The PBF was thin; its surface was broad, easily separable of the overlying subcutaneous and underlying muscular planes in its upper two thirds. It was richly blood supplied by two main pedicles:

the posterior brachial neurocutaneous branch and

The well vascularized area was 115mm long and 54mm broad in average. These two pedicles were quite constant (respectively 17 cases and 14 cases out of the 18 specimens) and of sufficient caliber to allow microsurgical anastomoses in good conditions. A rich venous network, satellite of the arteries, was always present. An arterial by-pass between both arterial pedicles could spare venous sutures when both arterial pedicles are present and communicating within the fascial depth (13 cases out of 18). Harvesting the fiap was easy through a posteromedial approach in a patient in supine position. The donor site could always be closed and its scare was well acceptable.

The first clinical case is presented in a patient suffering from recurrent tendinous adhesions at the dorsum of the hand after a close trauma with extensive hematoma, after failure of 2 previous tenolyses. After a third tenolysis, the free PBF fiap was performed. The fascia was covered with a free skin graft at day 6. The coverage was nice and the outcome of the tenolysis at 6 month was -15/80 (active motion) and +20/100 (passive motion).