Aims

An objective technological solution for tracking adherence to at-home shoulder physiotherapy is important for improving patient engagement and rehabilitation outcomes, but remains a significant challenge. The aim of this research was to evaluate performance of machine-learning (ML) methodologies for detecting and classifying inertial data collected during in-clinic and at-home shoulder physiotherapy exercise.

Introduction

The ceramic-on-ceramic strategy in acetabular revision faces potential limitations due to the femoral stem, as the implantation of ceramic ball head on a previously used taper is not recommended. Delta (r) ball heads with titanium sleeves have been proposed to avoid femoral revision. The study reports a minimum 3 years follow-up experience using this strategy.

Intraoperative assessment of knee kinematics should help surgeons optimizing total knee replacement. The purpose of this work was to validate information delivered by an adapted navigation system in 10 healthy cadaver knees and to investigate kinematics of 10 osteoarthritic (OA) knees in patients undergoing total knee replacement. The system displayed the magnitude of axial rotation, the position of the instantaneous centre of axial rotation and the displacements of the condyles. Successive cycles from full extension to 140° of fiexion in the same knee produced a mean external rotation of 19.7±10°, which was correlated to knee fiexion (r=0,60±0.2 in healthy knees, r=0.79±0.14 in OA knees). The center of axial rotation migrated posteriorly an average of 8.2 mm in both groups. The posterior displacements were 4.0 ±5.4 mm in healthy and 5±6.3 mm in OA knees for the medial condyle, and 20.9±9.1 mm in healthy and 20.3±10 mm in OA knees for the lateral condyle. The medial condyle lifted off beyond 110° of fiexion. Results in healthy knees were consistent with those obtained using fiuoroscopy and dynamic MRI. The kinematics of healthy and of OA knees with an intact anterior cruciate ligament did not differ significantly.

Aim of this study was to compare the postoperative range of motion of three types of total knee replacements.

They were 72 posterior cruciate ligament retaining knee prostheses (group I), 61 postero-stabilized (group II), 52 ultracongruent plates (group III). Inclusion criteria were primary arthritis with varus deformity inferior to 15 degrees (°), no previous surgery on the knee, body mass index inferior to 35, preoperative flexion superior to 110°. All prostheses were performed with the same ancillary with one unique surgeon (DH). Recovery and analgesia protocols were similar in the three groups. Mobility was measured using a goniometer.

Continuous data were tested for normal distribution using Kolmogorov-Smirnov test. Normally distributed data were analyzed with two tailed t-tests, whereas non-parametric data were analyzed with Mann-Whitney U test. Statistical significance was set at p < 0.05.

At 2 years follow-up, the group I demonstrated a mean flexion of 121.8° in preoperative period and 110.3° in postoperative period. They were respectively of 121.3 and 122.2° in the group II. Regarding group III, they were 121.6 °preoperatively and 118.4° postoperatively.

Results were significant (p< 0.05) between groups I and II, and groups I and III.

No statistic correlation was found between need of mobilisation under general anesthesia (p> 0.05), flexum (p> 0.05), knee score (p> 0.05), patient satisfaction depending on type of prostheses (p> 0.05).

Posterior cruciate ligament removal tends to offer a best postoperative flexion without significant influence on the knee score or patient satisfaction.

Purpose: Patellar complications are among the most frequent after total knee arthroplasty. Encasing the patellar piece is one way of resisting the shear forces leading to loosening.

Material and Methods: We studied at more than five years the results obtained with a total knee prosthesis implanted with preservation of the posterior cruciate ligament (PCL). This prosthesis has an asymmetric encased patellar insert with a cemented central pivot. The instrumentation ensures patellar thickness. We reviewed 104 implants at more than five years. Six had been lost to follow-up. Ninety-eight implants were still in place.

Results: The following complications were observed: four fractures of the upper rim with little displacement (these fractures healed and pain regressed but the insert had moved); three vertical patellar fractures with little displacement (these fractures healed; two were symptomatic temporarily); one transverse fracture of the upper pole with displacement causing a defect in active extension; eight moderate asymptomatic impactions which were visible on the lateral x-ray (modified orientation of the insert with cement fracture). There was no significant difference for functional results (pain 40.9; movement 21.9; knee score 84.3) between patients with or without a patellar complication.

Discussion: Insertion of an asymmetric prosthesis increased the risk of an orientation error (two cases early in our experience). Encasing the patellar insert limits medialisation yet the centering was satisfactory (centred patella 95.2%, shift 3.6%, subluxation 1.2%). Encasing provides a peripheral wall protecting against transverse sheer forces. The lateral wall did not fracture, demonstrating its efficacy. The upper wall can fracture under the force of flexion without functional consequences. The other fractures, favoured by section of the lateral patellar wing (p< 0.05), were not treated. Moderate but certain impaction was noted in eight cases at a mean 3.5 years (1–6 years). It was due to failure of bony support under the effect of the compression forces applied on a small surface. The diameter of the encased patellar inserts was rarely more than 25 mm. Once the prosthesis is in place, the periphery of the patella is the only component articulating with the trochlea and its impaction does not cause further aggravation. This contact did not lead to pain in any patients.

Conclusions: Complications observed with encased patellar components differ from the better known apposed prostheses.

Anterior approaches have been suggested for THP revision in order to reduce dislocation rate. However, the exposure is considered to be more strenuous. The goal of the study was to evaluate if anterior approach in lateral position may improve the exposure.

From 2005 to 2007, 47 patients underwent THP revision, 34 times on the acetabular side, 2 times on the femoral side and 11 patients had a bipolar revision. Mean age was 64 years and mean BMI was 23. Patients were positioned on the lateral side and had an antero-lateral approach. During the femoral procedure, the leg was placed in a sterile bag stuck on the lateral side in order to optimize the exposure by positioning the femur in adduction and posterior translation.

Acetabular and femoral exposures were achieved correctly in all the cases allowing to perform all the revisions using this technique and no additional approach was needed in any patient. Antero-posterior femorotomies were performed in 7 patients for stem replacement and cement extraction, without any specific complication. Early post-operative anterior dislocations occurred in 2 patients who underwent monopolar cup revision. Dislocation was explained by an excessive anteversion of the remaining stems. 2 patients had an incomplete and transitory sciatic deficiency due to excessive posterior translation of the femoral head in the sciatic notch.

Using this technique, THP revision seems to be achievable even in complicated cases requiring stem revision and femorotomy. Dislocation rate was low; however a larger cohort is needed to confirm these preliminary results.

The new technology using femoral heads with sleeves allows conservative procedures for revision hip arthroplasty. The implantation of classical ceramic heads on a previously used femoral taper is not recommanded. When there is no loosening of the femoral implant, the use of sleeves is a good solution for using an alumine on alumine couple, specially in young and active patients.

Material and methods: 25 hips in 25 patients were included. In 12 cases the cause of revision was an acetabular osteolysis with or without loosening in metal on metal cimented THR.

In 13 patients the revision was performed for a loosening and a wear of the PHE cup with osteolysis (4 zyrcon and 9 chrome-cobalt heads). The mean age was 49 years for the metal on metal revisions (36 to 75) and 54 years for the prosthesis using a polyethylen socket.

Cementless cups were implanted using XLW delta alumina inserts. The 32 mm delta alumina sleeved heads were adjusted on the existing femoral 12–14 tapers. Patients were evaluated preoperatively and followed-up with clinical and radiological examinations.

Results: At 2 years mean follow-up, average Harris Hip Score was significantly improved (97 vs 54, p< 0.05). We did not observe ceramic fracture or squeaking. The radiographic results did not demonstrate acetabular loosening, osteolysis, or femoral abnormalities.

Concerning the metal on metal revisions, the aseptic loosening of the socket was combined with high rates of cobalt and chromium serum levels. Mean delay before revision was 4 years (2 to 11). Unipolar acetabular revisions were only decided after a carefull inspection of the remaining stems to detect any taper alteration or impingement lesions.

Postoperative cobalt and chromium serum levels significantly decreased postoperatively.

Concerning the metal on PHE and the zyrcon on PHE revisions, the mean delay before revison was 11 years (4 to 21).

At this short follow up, we did not notice any parasitic impingement due to the additional sleeve or any ceramic fracture or squeaking. The radiographic results did not demonstrate acetabular loosening, osteolysis, or femoral abnormalities.

Discussion: Failures of metal-on-metal or metal on PHE hip arthroplasties raise new technical problems. Conversion to ceramic on ceramic has been suggested in case of hypersensibility reactions or high rate of serum metal ions, and in case of osteolysis in young population. This prospective study evaluates a revision strategy using ceramic cups and delta ceramic heads with titanium adapter sleeves when a femoral revision is not required. Despite the limitation due to short follow-up, this technical option should be considered when wear surfaces exchange is decided.

Purpose of the study: Fragile bone and weak soft tissues can create a serious challenge for arthroplasty of the rheumatoid arthritis shoulder. Patients seen late after rotator cuff tears become irreparable may also present a stiff shoulder, further complicating the procedure.

Material and methods: The purpose of this study was to assess outcome at more than five years in a prospective series of 12 patients with rheumatoid arthritis of the shoulder with an irreparable rotator cuff tear treated with a hemiarthroplasty with a mobile cup. The radiological and clinical results were compared with those obtained in a control series of ten bipolar humeral prostheses implanted for centered or excentered degenerative disease with irreparable cuff tears.

Results: The mean preoperative Constant score was 16.9 points: pain 2.5, activity 4.2, active mobility 9.5, strength 0.7. Active ROM was 63.8° for anterior elevation, 45° for abduction, and 12° for external rotation. At last follow-up, the mean postoperative Constant score was 39.4 points: pain 10.7, activity 10.8, active mobility 13.8, strength 4.1. Mean active anterior elevation was 83.7°, abduction 70.4°, and external rotation 29.1°. Outcome was not significantly different from the control group with degenerative joint disease (p< 0.05).

Discussion: The overall Constant score, especially the pain score, was significantly improved (p< 0.05). Improvement in joint motion was modest but comparable with other series in the literature and even better than with conventional hemiarthroplasty for the same indication. There were few complications, mainly superior subluxation favored by the preoperative infra-scapularis or infraspinatus tears. Glenoid wear was significant despite the dual mobility concept. There were no cases of loosening.

Conclusion: These results show that hemiarthroplasty with a mobile cut provides acceptable mid-term results for the advanced-stage rheumatoid shoulder with an irreparable rotator cuff tear. Results in this series were comparable with that in the control group of patients with degenerative joint disease. Consequently, the status of the rotator cuff appears to be more important that the inflammatory or degenerative etiology. Certain cuff tears involving the infrascapularis raise the risk of superoanterior instability and could be a limitation for this method. A more constrained prosthesis might be advisable.

Purpose of the study: Opinions vary concerning results after knee arthroplasty with preservation of the posterior cruciate ligament (PCL) in patients with rheumatoid disease. We report our findings in patients reviewed more than ten years after implantation in comparison with patients treated for osteoarthritis.

Material and methods: One surgeon implanted 43 knee arthroplasites (Kali) with preservation of the PCL (9 bilateral cases) in 31 women and 3 men, mean age 53 years (range 30–70 years). Outcome was assessed with the AKS clinical and radiological scores. Passive recur-vatum and posterior drawer at 90° flexion were measured radiographicaly at last follow-up. Outcome was compared with the results observed in a control group of 29 prostheses of the same type implanted for osteoarthritis (among a total of 203 implantations).

Results: There were no patients lost to follow-up: two patients were removed from the analysis due to infection on early wound necrosis and late metastatic infection. Eleven patients (16 prostheses) died before ten years follow-up; outcome was satisfactory for the prosthesis. Twenty-one patients (25 prostheses) were reviewed at more than ten years, mean follow-up 136 months. There was one case of supracondylar fracture which healed without sequela after osteosynthesis. The mean knee score was 34.3 preoperatively and 87.2 postoperatively with a mean function score improvement from 17 to 44 points. The pain score (47.3 points on average, was significantly improved while joint range of motion remained unchanged (117°). There were no worrisome lucent lines. Mean recurvatum measured radiographically was 6.9° (range 3–14°) and mean posterior drawer at 90° flexion was 4.2 mm. Outcome in the control group was the same excepting (p< 0.05) for lesser range of motion (109.7°) and better function score (62 points). Laxity (clinical and radiographic scores) were the same.

Discussion: The results obtained in patients with rheumatoid disease were satisfactory and the same as those obtained in patients with osteoarthritis and were comparable to those with prostheses sacrificing and replacing the PCL. There were no cases of prosthesis loosening. Complications were very limited and less frequent than among the entire population of 203 prostheses for degenerative disease.

Conclusion: Ligament alterations are not a contraindication for preservation of the PCL in patients with rheumatoid arthritis. Irrespective of the etiology, the main limitation on prosthesis longevity is polyethylene wear observed beyond ten years (ten changes of the plateau because of wear among 246 prostheses).

Purpose: The purpose of this study was to compare the reliability and reproducibility of anterior knee laxity measurements made with the KT1000 arthrometere (Medmetric) and radiographically with Telos. The Telos measurement was taken as the standard system.

Material and methods: Inclusion criteria were preoperative anterior laxity differential less than 10 mm, a healthy contralateral knee, and intra-articular surgery. Between January 2001 and December 20001, 147 patients underwent surgery for free graft repair of anterior laxity. Both measurement methods, KT1000 and Telos were used to measure both knees before surgery and at mean 16 months postsurgery. KT1000 measurements were taken at 67N, 89N, 134N and maximum manual force. Telos was measured at 150 N as recommended by the manufacturer. A differential laxity measured at more than 3 mm was considered pathological for KT1000 and greater than 5 mm for Telos. We also determined the intrao-bserver reproducibility (experimented operators) with both methods on the 147 healthy knees considering the measurements taken preoperatively and postoperatively.

Results: Mean preoperative differential laxity was 4.2±2.4 with KT1000 at 89N and 6.3±3.1 mm at maximal manual force. It was 7.7±3.4 mm with Telos. The mean postoperative differential laxity with KT1000 was 2.1±2.2 mm at 89N and 2.6±2.5 mm at maximal manual force. With Telos it was 3±3.6 mm. The Telos values showed a wider distribution than the KT1000 values (p< 0.03). The sensitivity with Telos was 72% with 28% false negatives. With KT1000, the sensitivity improved with greater traction. It was 65% at 89N, 73% at 134N and 92% at maximal manual force. For the healthy knee, the anterior laxity measurements taken by an experimented operator were reproducible with KT1000, p=0.04, kappa = 7.8.

Discussion: The sensitivity and reproducibility results as well as the narrow distribution of the values show that KT1000 is a reliable method for the measurement of anterior knee laxity. Its use can be recommended in routine practice due to the good benefit-cost ratio. The low sensitivity is a drawback of the Telos method due to the high percentage of false negatives. Its use in routine practice should be revisited.

Purpose: Prognosis of open leg fractures is better when cover flaps are used early to cover tissue loss. Beyond eight days after high-energy trauma (Byrd stage III and IV), the therapeutic strategy requires discussion. The purpose of this study was to analyse the influence of flap covers on these complex fractures.

Material and methods: We conducted a retrospective analysis of 26 patients operated on from 1996 to 201. The therapeutic sequence was debridement, external fixation, and flap cover. High-energy trauma predominated (n=21). We used homolateral leg flaps (n=24, ten muscle flaps and 14 fasciocutaneous flaps) and free latissimus dorsi flaps (n=2). Flap cover was performed on day 8 (n=13), between day 8 and day 45 (n=11), or after day 45 (n=2).

Results: Cover flaps failed in eight cases requiring revision surgery. Time to cover or type of flap was not statistically related with initial severity of the injury. Time to cover influenced the type of flap chosen by the surgeons: 8/13 muscle flaps performed before day 8 versus 10/13 fasciocutaneous flaps after day 8 (p< 0.05). Complementary bone grafts were used for 18 patients before the third month leading to bone healing before ten months. Serious infection occurred in 16.6% of patients in the group treated before day 8 and in 36.66% of patients in the group treated after day 8. The severity of the initial injury and time to cover were not predictive of functional outcome.

Discussion: Proper management of high-energy leg fractures (Byrd stage III and IV) remains controversial. Most authors prefer external fixation to achieve skeletal stability. The growing interest for plastic surgery techniques for the leg segment has led to using locoregional homolateral leg flaps even after day 8. At this phase, we prefer muscle flaps. This attitude has demonstrated its usefulness in terms of healing time and its limitations due to the high risk of infection. Complementary bone grafting is performed before three months if signs of correct bone healing are absent on the control x-rays.

Purpose: Patellar complications are among the most frequent after total knee arthroplasty. Encasing the patellar piece is one way of resisting the shear forces leading to loosening.

Material and methods: We studied at more than five years the results obtained with a total knee prosthesis implanted with preservation of the posterior cruciate ligament (PCL). This prosthesis has an asymmetric encased patellar insert with a cemented central pivot. The instrumentation ensures patellar thickness. We reviewed 104 implants at more than five years. Six had been lost to follow-up. Ninety-eight implants were still in place.

Results: The following complications were observed: four fractures of the upper rim with little displacement (these fractures healed and pain regressed but the insert had moved); three vertical patellar fractures with little displacement (these fractures healed; two were symptomatic temporarily); one transverse fracture of the upper pole with displacement causing a defect in active extension; eight moderate asymptomatic impactions which were visible on the lateral x-ray (modified orientation of the insert with cement fracture). There was no significant difference for functional results (pain 40.9; movement 21.9; knee score 84.3) between patients with or without a patellar complication.

Discussion: Insertion of an asymmetric prosthesis increased the risk of an orientation error (two cases early in our experience). Encasing the patellar insert limits medialisation yet the centering was satisfactory (centred patella 95.2%, shift 3.6%, subluxation 1.2%). Encasing provides a peripheral wall protecting against transverse sheer forces. The lateral wall did not fracture, demonstrating its efficacy. The upper wall can fracture under the force of flexion without functional consequences. The other fractures, favoured by section of the lateral patellar wing (p< 0.05), were not treated. Moderate but certain impaction was noted in eight cases at a mean 3.5 years (1–6 years). It was due to failure of bony support under the effect of the compression forces applied on a small surface. The diameter of the encased patellar inserts was rarely more than 25 mm. Once the prosthesis is in place, the periphery of the patella is the only component articulating with the trochlea and its impaction does not cause further aggravation. This contact did not lead to pain in any patients.

Conclusions: Complications observed with encased patellar components differ from the better known apposed prostheses.