Biologic principles of bone induction

This article provides a concise review of bone induction. Bone induction by demineralized bone matrix is a multistep cascade. The purification and elucidation of the chemistry of osteogens will improve bone grafting methods.     

T1 pelvic angle is associated with rapid progression of hip arthrosis

Purpose

To evaluate the association between global spinal malalignment and rapid progression of hip arthrosis.

Methods

This was a retrospective, case–control study including 90 patients, contributing 90 hips, who underwent hemi- or total hip arthroplasty at our institution. For analysis, hips were classified into a rapid progression group, defined as ≥ 2 mm destruction of the femoral head or loss of the hip joint space within a 12-month period (n = 30), and a non-rapid progression group, defined by no observable hip disease progression over a period more than 12 months (n = 60). Logistic regression analysis identified factors that predicted rapid progression, with a receiver operating characteristic curve analysis used to confirm factors.

Results

Significant between-group differences were identified for the following parameters: pelvic tilt (P = 0.002, PT), sagittal vertical axis (P = 0.002, SVA), and T1 pelvic angle (P < 0.001, TPA). On multiple logistic regression, PT (P = 0.002), SVA (P = 0.002), and TPA (P < 0.001) were predictive of a rapid progression on hip arthrosis, with the area under the curve being greater for TPA than PT (P = 0.035).

Conclusion

Global spinal alignment is associated with rapid progression of hip arthrosis. TPA could assist in identifying patients at risk for rapid progression of hip arthrosis, allowing for time management.

     

Glenohumeral instability and arthrosis

Although the development of arthrosis is rare following shoulder dislocations, it represents a significant problem if it develops after surgery for shoulder instability. The incidence of arthrosis may be decreased by correct diagnosis of the instability and appropriate surgical technique. However, should it occur, shoulder arthroplasty should be considered.     

The progression of patellofemoral arthrosis after medial unicompartmental replacement: results at 11 to 15 years

This study reports the 11-year to 15-year results of unicompartmental knee arthroplasty with an emphasis on failure mechanisms and progression of patellofemoral arthrosis. In a prospective study of 513 consecutive potential knee replacement candidates, 59 patients (12%) had medial unicompartmental arthroplasty of the knee. All 59 patients had isolated unicompartmental disease without clinical symptoms or radiographic evidence of patellofemoral arthritis. No patient was lost to followup. The average followup was 13 years (range, 11-15 years). The mean preoperative Hospital for Special Surgery knee score of 55 points (range, 30-79 points) improved to a mean of 90 points (range, 60-100 points) at final followup. Patellofemoral symptoms were present in 1.6% of patients at 10 years; this increased markedly to 10% of patients at 15 years (p < 0.01). Four patients (10%) had moderate or severe patellofemoral symptoms at final followup; two were revised to a primary total knee replacement at 7 and 11 years for progressive patellofemoral degeneration. No component was radiographically loose and no osteolysis was seen. The Kaplan-Meier survival with loosening or revision for any reason was 98.0% +/- 2.0% at 10 years and 95.7% +/- 4.3% at 15 years. At up to 15 years, unicompartmental knee arthroplasty yielded good clinical results; however, progressive patellofemoral arthritis was the primary mode of failure.     

Chondrocyte apoptosis and posttraumatic arthrosis

Apoptosis, or programmed cell death, plays an important role in many normal and pathologic conditions. This article has been designed to introduce the concept of chondrocyte apoptosis and how it may contribute to posttraumatic arthrosis following articular injury. Available means of assessing chondrocyte apoptosis are presented, in addition to the findings of in vitro and in vivo studies of cartilage injury. Unfortunately, despite active research in this area, the exact contribution chondrocyte apoptosis makes following joint injury to the development of posttraumatic arthrosis is unknown.     

Molecular biology of progression of prostate cancer.

Despite the clinical importance of prostate cancer, the molecular mechanisms underlying the development and progression of prostate cancer are poorly understood. The lack of knowledge on the mechanisms has probably been one of the most important reasons why no new treatment modalities have been developed to cure the disease. Recent studies, especially those performed by comparative genomic hybridization, have revealed the frequent chromosomal alterations that most likely harbor the genes critical for the progression of prostate cancer. Such genetic aberrations include losses of 8p, 10q, 16q, and 13q as well as gains of 7p, 7q, 8q, and Xq. Unfortunately, the target genes for these alterations are, in most of the cases, not known. We have recently identified the androgen receptor (AR) gene as a target gene for the Xq12 amplification found in one-third of the hormone-refractory prostate cancer. The findings suggest that the AR gene amplification and overexpression is involved in the emergence of hormone-refractory prostate cancer.     

Shoulder arthrodesis for paralysis and arthrosis

Twenty-three patients with a mean age of 35 years (11 males and 12 females) were reexamined 6 years after shoulder fusion. Indication for the operation was shoulder paralysis in 14 cases and arthrosis in 9. In 4 patients the operation had to be repeated because of nonunion. Eighteen patients had improved function, particularly in bringing the hand to the midline of the body, to the face, and to the side pocket. However, bringing the hand to the back and the anal region often deteriorated. One third of the patients, mainly those with arthrosis, had considerable shoulder pain at the follow-up.     

Radiographic classification of glenohumeral arthrosis

We studied the interobserver agreement of two radiographic classification systems for evaluation of glenohumeral arthrosis in 40 patients at long-term follow-up after the Eden Hybbinette operation for habitual dislocation of the anterior shoulder. Both observers agreed that none of the patients had severe arthrosis. The Samilson-Prieto system showed agreement using the classification in 35 of 40 operated shoulders (kappa 0.76). The Kellgren-Lawrence system showed agreement using the classification in 23 of 40 operated shoulders (kappa 0.36). The rate of arthrosis in the operated shoulder ranged from 0.2 to 0.6, depending on the classification system and the observer. None of the patients without arthrosis, but one fifth of those with arthrosis reported pain. The Samilson-Prieto classification is preferable because it is simple to use and has excellent interobserver agreement.     

Shoulder arthrodesis for paralysis and arthrosis

Twenty-three patients with a mean age of 35 years (11 males and 12 females) were reexamined 6 years after shoulder fusion. Indication for the operation was shoulder paralysis in 14 cases and arthrosis in 9. In 4 patients the operation had to be repeated because of nonunion. Eighteen patients had improved function, particularly in bringing the hand to the midline of the body, to the face, and to the side pocket. However, bringing the hand to the back and the anal region often deteriorated. One third of the patients, mainly those with arthrosis, had considerable shoulder pain at the follow-up.