Patrick Boyer

In-vivo glenohumeral translation and ligament elongation during abduction and abduction with internal and external rotation.

Study DesignBasic Science. To investigate humeral head translations and glenohumeral ligament elongation with a dual fluoroscopic imaging system.BackgroundThe glenohumeral ligaments are partially responsible for restraining the humeral head during the extremes of shoulder motion. However, in-vivo glenohumeral ligaments elongation patterns have yet to be determined. Therefore, the objectives of this study were to 1) quantify the in-vivo humeral head translations and glenohumeral ligament elongations during functional shoulder positions, 2) compare the inferred glenohumeral ligament functions with previous literature and 3) create a baseline data of healthy adult shoulder glenohumeral ligament lengths as controls for future studies.MethodsFive healthy adult shoulders were studied with a validated dual fluoroscopic imaging system (DFIS) and MR imaging technique. Humeral head translations and the superior, middle and inferior glenohumeral ligaments (SGHL, MGHL, IGHL) elongations were determined.ResultsThe humeral head center on average translated in a range of 6.0mm in the anterior-posterior direction and 2.5mm in the superior-inferior direction. The MGHL showed greater elongation over a broader range of shoulder motion than the SGHL. The anterior-band (AB)-IGHL showed maximum elongation at 90° abduction with maximum external rotation. The posterior-band (PB)-IGHL showed maximum elongation at 90° abduction with maximum internal rotation.DiscussionThe results demonstrated that the humeral head translated statistically more in the anterior-posterior direction than the superior-inferior direction (p = 0.01), which supports the concept that glenohumeral kinematics are not ball-in-socket mechanics. The AB-IGHL elongation pattern makes it an important static structure to restrain anterior subluxation of the humeral head during the externally rotated cocking phase of throwing motion. These data suggest that in healthy adult shoulders the ligamentous structures of the glenohumeral joint are not fully elongated in many shoulder positions, but function as restraints at the extremes of glenohumeral motion. Clinically, these results may be helpful in restoring ligament anatomy during the treatment of anterior instability of the shoulder.

Outcome and serum ion determination up to 11 years after implantation of a cemented metal-on-metal hip prosthesis.

Background and purpose Little is known about the long-term outcome of cemented metal-on-metal hip arthroplasties. We evaluated a consecutive series of metal-on-metal polyethylene-backed cemented hip arthroplasties implanted in patients under 60 years of age. Methods 109 patients (134 joint replacements) were followed prospectively for mean 9 (7–11) years. The evaluation included clinical score, radiographic assessment, and blood sampling for ion level determination. Results At the final review, 12 hips had been revised, mainly because of aseptic loosening of the socket. Using revision for aseptic loosening as the endpoint, the survival rate at 9 years was 91% for the cup and 99% for the stem. In addition, 35 hips showed radiolucent lines at the bone-cement interface of the acetabulum and some were associated with osteolysis. The median serum cobalt and chromium levels were relatively constant over time, and were much higher than the detection level throughout the study period. The cobalt level was 1.5 μg/L 1 year after implantation, and 1.44 μg/L 9 years after implantation. Interpretation Revisions for aseptic loosening and radiographic findings in the sockets led us to halt metal-on-metal-backed polyethylene cemented hip arthroplasty procedures. If the rigidity of the cemented socket is a reason for loosening, excessive release of metal ions and particles may be involved. Further investigations are required to confirm this hypothesis and to determine whether subluxation, microseparation, and hypersensitivity also play a role.

Optimization of total hip arthroplasty implantation: is the anterior pelvic plane concept valid?

The anterior pelvic plane (APP) is currently used as superficial anatomical landmark for three-dimensional orientation during total hip arthroplasty (THA), specifically when using computer aided surgery. However, the actual parameter for characterizing the pelvic orientation is the sacral slope, which correlates with other functional spinal parameters. The goal of the paper was to investigate relationships between APP and sacral slope. Both were measured on 328 lateral radiographs of the pelvis in standing position by two observers. The poor correlation between APP and sacral slope suggest keeping using the reference to the APP for the per-operative orientation in the 3D space, while individually adjusting the preoperative planning to the sacral slope.

In vivo articular cartilage contact at the glenohumeral joint: preliminary report

BackgroundLittle is known about normal in vivo mechanics of the glenohumeral joint. Such an understanding would have significant implications for treating disease conditions that disrupt shoulder function. The objective of this study was to determine articular contact locations between the glenoid and humeral articular surfaces in normal subjects during shoulder abduction with neutral, internal, and external rotations. We hypothesized that glenohumeral articular contact is not perfectly centered and is variable in normal subjects tested under physiological loading conditions.MethodsOrthogonal fluoroscopic images and magnetic resonance image-based computer models were used to characterize the centroids of articular cartilage contact of the glenohumeral joint at various static, actively stabilized abduction and rotation positions in five healthy shoulders. The shoulder was investigated at 0°, 45°, and 90° abduction with neutral rotation and then at 90° abduction combined with active maximal external rotation and active maximal internal rotation.ResultsFor all the investigated positions, the centroid of contact on the glenoid surface for each individual, on average, was more than 5 mm away from the geometric center of the glenoid articular surface. Intersubject variation of the centroid of articular contact on the glenoid surface was observed with each investigated position, and 90° abduction with maximal internal rotation showed the least variability. On the humeral head surface, the centroids of contact were located at the superomedial quarter for all investigated positions, except in two subjects’ positions at 0° abduction, neutral rotation.ConclusionsThe data showed that the in vivo glenohumeral contact locations were variable among subjects, but in all individuals they were not at the center of the glenoid and humeral head surfaces. This confirms that “ball-in-socket” kinematics do not govern normal shoulder function. These insights into glenohumeral articular contact may be relevant to an appreciation of the consequences of pathology such as rotator cuff disease and instability.

Intratendinous Injection of Platelet-Rich Plasma under US Guidance to Treat Tendinopathy: A Long-Term Pilot Study

PURPOSE To assess the potential therapeutic effect of intratendinous injection of platelet-rich plasma (PRP) under ultrasound (US) guidance to treat tendon tears and tendinosis in a pilot study with long-term follow-up. MATERIALS AND METHODS The study included 408 consecutive patients referred for treatment by PRP injection of tendinopathy in the upper (medial and lateral epicondylar tendons) and the lower (patellar, Achilles, hamstring and adductor longus, and peroneal tendons) limb who received a single intratendinous injection of PRP under US guidance. Clinical and US data were retrospectively collected for each anatomic compartment for upper and lower limbs before treatment (baseline) and 6 weeks after treatment. Late clinical data without US were collected until 32 months after the procedure (mean, 20.2 months). The McNemar test and regression model were used to compare clinical and US data. RESULTS QuickDASH score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and residual US size of lesions were significantly lower after intratendinous injection of PRP under US guidance at 6 weeks and during long-term follow-up compared with baseline (P < .001 in upper and lower limb) independent of age, gender, and type of tendinopathy (P > .29). No clinical complication was reported during follow-up. CONCLUSIONS Intratendinous injection of PRP under US guidance appears to allow rapid tendon healing and is well tolerated.

Visual Impairment and Hip Fractures: A Case-Control Study in Elderly Patients

Aims: To investigate the relationship between visual impairment and fall-related hip fracture and to determine the etiology of visual impairment in a population of elderly patients with hip fracture. Methods: A case-control study compared 96 patients diagnosed with hip fracture to a randomly selected control group of 103 patients without hip fracture. Inclusion criteria for the case group were as follows: patients aged 60 years and over with a hip fracture. Clinical assessment included visual acuity and ophthalmic examination. Results: Forty-three patients with hip fracture had a visual impairment compared to only 12 patients in the control group. Visual impairment was a significant risk factor for hip fracture (OR = 6.15; 95% CI 2.98-12.69). Twenty-seven hip fracture patients had an uncorrected refractive error compared to only 15 controls (OR = 2.78; 95% CI 0.92-8.35). There was no significant difference of dense cataract between both groups (OR = 2.28; 95% CI 0.75-6.93). Fourteen hip fracture patients had a macular degeneration compared to only 8 controls (OR = 5.63; 95% CI 1.57-20.18), and 10 patients had suspicion of glaucoma compared to only 5 controls (OR = 10.65; 95% CI 2.21-51.3). Conclusion: Visual impairment was significantly associated with an increased risk of hip fracture in elderly people. There are many etiologies that may contribute to hip fractures, most notably refractive error, cataract, macular degeneration and glaucoma.

Feasibility of individual patient data meta-analyses in orthopaedic surgery

BackgroundThe number of individual patient data meta-analyses published is very low especially in surgical domains. Our aim was to assess the feasibility of individual patient data (IPD) meta-analyses in orthopaedic surgery by determining whether trialists agree to send IPD for eligible trials.MethodsWe performed a literature search to identify relevant research questions in orthopaedic surgery. For each question, we developed a protocol synopsis for an IPD meta-analysis and identified all related randomized controlled trials (RCTs) with results published since 2000. Corresponding authors of these RCTs were sent personalized emails that presented a project for an IPD meta-analysis corresponding to one of the research questions, with a link to the protocol synopsis, and asking for IPD from their RCT. We guaranteed patient confidentiality and secure data storage, and offered co-authorship and coverage of costs related to extraction.ResultsWe identified 38 research questions and 273 RCTs related to these questions. We could contact 217 of the 273 corresponding authors (79 %; 56 had unavailable or non-functional email addresses) and received 68/273 responses (25 %): 21 authors refused to share IPD, 10 stated that our request was under consideration and 37 agreed to send IPD. Four corresponding authors required authorship and three others asked for financial support to send the IPD. Overall, we could obtain IPD for 5,110 of 33,602 eligible patients (15 %). Among the 38 research questions, only one IPD meta-analysis could be potentially initiated because we could receive IPD for more than 50 % of participants.ConclusionThe present study illustrates the difficulties in initiating IPD meta-analyses in orthopaedic surgery. Significant efforts must be made to improve data sharing.

Charcot Spine and Parkinson's Disease

Charcot spine is rare condition whose association with Parkinsons disease (PD) has not been reported yet. The authors reported the cases of two patients with PD who developed Charcot spine. Both patients presented with a history of back pain and bilateral radicular leg pain. They had complete clinical and radiological assessment. Lumbar spine was involved in both patients. Clinical features and response to treatment were described. In the first case, circumferential fusion and stabilization were performed on the dislocated vertebral levels. A solid and stable fusion of the spine was obtained with satisfactory clinical outcome. Surgical treatment has been recommended to the other patient. In both cases, no other neurological etiology was found to account for Charcot spine. In conclusion, Charcot spine is associated with several neurological affections but has not previously been reported in association with Parkinsons disease.

Results of heterodigital flexor digitorum profundus hemi-tendon transfer for 23 flexor tendon injuries in zones 1 or 2:

We report outcomes of reconstruction of zone 1 or 2 flexor tendon injuries using a heterodigital hemi-tendon transfer of the flexor digitorum profundus in 23 fingers of 23 patients. At mean follow-up of 57 months, the mean total active motion of the three finger joints including the metacarpophalangeal joint was 128 degrees preoperatively and 229 degrees at final follow up. According to Strickland criteria, the function was excellent for 14 fingers, good for seven fingers and poor for two fingers. The subgroup analysis showed that the results were better in cases of primary surgery, children, and for the index and little fingers. Complications included stiffness of three fingers, and rupture in one finger that was converted to a two-stage tendon reconstruction. We conclude that this technique restores good function in most patients with zone 1 and 2 flexor tendon injuries, in which primary tendon repair has not been performed or was unsuccessful, and where pulley reconstruction is not required. Level of evidence: IV

Idiopathic bilateral lunate and triquetrum avascular necrosis: A case report

We report on the case of bilateral avascular osteonecrosis (AVN) of the lunate and triquetrum in a 45-year-old woman without any relevant medical history for which the cause could not be established. She was treated conservatively with splinting and analgesics. The patient was able to pursue her work and hobbies with subnormal range of motion at 1-year follow-up. AVN of the triquetrum is very rare, as it is a richly vascularized bone. The presence of AVN in multiple carpal bones has only been described in patients receiving high doses of corticosteroids. To our knowledge, there are no other cases of idiopathic AVN of multiple carpal bones in the literature.