Medial Arthrotomy Research Articles

Fragmented Coronoid Process Associated with Premature Distal Radial Physeal Closure in Four Dogs

SummaryFragmented coronoid process occurred in four dogs with humeroradial subluxation secondary to premature closure of the distal radial physis. The medial coronoid process was affected in three dogs but in the fourth dog a single osteochondral fragment was located between the medial and lateral coronoid processes. One dog was treated by medial arthrotomy and lengthening of the radius. In three dogs the fragment was removed via a lateral arthrotomy accomplished by proximal ulnar diaphyseal osteotomy and the ulna was shortened at the ulnar osteotomy site to provide congruity of the proximal radio-ulnar and humeroradial articulations. The longterm clinical results were encouraging. The role of mechanical loading on the coronoid process in the pathogenesis of these cases is discussed.Four mature dogs were found to have fragmented coronoid process and humeroradial subluxation secondary to premature closure of the distal radial physis.It is proposed that the humero-radial subluxation placed ab-normal mechanical stress on the coronoid process of the ulna and caused its fracture or fragmentation.

Fragmentation of the medial coronoid process of the ulna in dogs: A study of 109 cases

ABSTRACTThe results of a combined retrospective and prospective study of 130 cases of fragmented coronoid process (FCP) in 109 dogs are presented. Sixty‐eight cases were treated surgically by medial elbow arthrotomy and 62 were treated medically (rest and anti‐inflammatories). Case records were searched with the emphasis on the severity of lameness, physical abnormalities and in surgical cases, the appearance of the coronoid process lesion. Long term follow‐up was obtained by a telephone survey. Analysis of case histories and physical data revealed no correlation between severity of lameness before treatment, severity of radiographic changes in the elbow joint and the type of lesion found at surgery. Surgical treatment did not decrease the incidence of post treatment lameness, but the surgically treated dogs were more active and less severely lame than those treated without surgery. It was concluded that young dogs with mild lameness due to FCP in the elbow probably do not benefit from surgical treatment but dogs with chronic, moderate to severe lameness have a better prognosis if treated surgically.

Intramedullary bone repair and ingrowth into porous coated implants in the adult chicken: a histologic study and biochemical analysis of collagens.

A new model was developed to study the histologic and biochemical events during intramedullary bone repair and ingrowth into porous coated implants. Adult chickens were used because of the availability of specific antibody probes. Repair in the metaphysis and diaphysis were compared. Entering through a medial arthrotomy, the distal tibiotarsus was reamed and either implanted with a double-ended porous coated rod or allowed to heal without implantation of a rod. Specimens analyzed histologically at 7, 14, 21, and 70 days postoperatively revealed direct formation of bone by osteoblasts with no evidence of a cartilaginous phase. At 70 days bony ingrowth was observed deep within the porous surface. Analysis of collagens with sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that the synthesis of type I collagen predominated. Biosynthetic data coupled with quantitative immunologic analyses using antibodies to type II and type X collagen showed that neither of these two collagen types, which are characteristic of cartilage undergoing endochondral ossification, were produced during intramedullary bone repair. These results establish that the adult chicken is capable of bony ingrowth into porous coated implants and that this process is through direct bone deposition by osteoblasts without a cartilaginous intermediate.

Patellar fractures in total knee arthroplasty

The incidence of patellar fractures following total knee arthroplasty varies from 3% to 21%. This problem has been attributed to avascular necrosis of the patella secondary to the surgical approach, including medial arthrotomy and lateral release, patellar bone resection, thermal necrosis, and anatomic variation. Management of these patellar fractures may be conservative or surgical.

RADIOGRAPHIC EVALUATION OF THE CANINE ELBOW JOINT WITH SPECIAL REFERENCE TO THE MEDIAL HUMERAL CONDYLE AND THE MEDIAL CORONOID PROCESS

The results of radiographic examination of clinically affected elbow joints in 14 young, large‐breed dogs, including standard and oblique projections and linear tomography, were compared with the findings of medial arthrotomy. Radiographs revealed arthrosis (13 dogs), osteochondrosis of the medial humeral condyle (2 dogs), fragmentation of the medial coronoid process (5 dogs), and a combination of osteochondrosis of the medial humeral condyle and fragmentation of the medial coronoid process (2 dogs). In one dog fissures in the medial coronoid process and in another dog a linear radiopacity along the articular surface of the medial coronoid process were found. In three dogs both medial humeral condyle and medial coronoid process appeared normal. The radiographic findings were confirmed during surgery in 11 dogs. Cartilage erosion of the medial humeral condyle in two dogs and of the medial coronoid process in one dog had not resulted in radiographically visible abnormalities. Radiographic examination of the elbow joints in young, large‐breed dogs should include standard mediolateral and craniocaudal projections, a mediolateral projection with the joint maximally extended and the leg supinated 15°, and a craniolateral‐to‐caudomedial projection.

Effects of Standard Surgical Procedures on the Patellar Blood Flow in Monkeys

The effects of various surgical dissections on the patellar blood flow were studied in ten monkeys by the use of the hydrogen washout technique. The patellar blood flow was decreased to an average of 65% of the control value after an extensive medial parapatellar arthrotomy. When the infrapatellar fat pad was completely removed following extensive medial arthrotomy, the blood flow further decreased to an average of 49% of the control. When a lateral retinacular release with sacrifice of the lateral superior genicular artery was performed following the medial arthrotomy, the blood flow decreased to an average of 53% of the control. When a lateral release was combined with removal of the fat pad following the main medial arthrotomy, the patellar blood flow showed marked decrease to an average of only 17% of the control. The vascular anatomic study demonstrated that many vessels penetrate from the fat pad into the inferior pole of the patella. It is suggested that the lateral superior genicular artery and/or the fat pad should be carefully preserved to avoid ischemia of the patella during extensive procedures such as total knee arthroplasty.

The saphenous nerve: its course and importance in medial arthrotomy.

Both lower extremities of 10 cadavers (20 specimens) were dissected to delineate the course of the saphenous nerve and its two major divisions (sartorial and infrapatellar branches). The course of the saphenous nerve followed the standard text description, except at the point in the sartorius muscle where the infrapatellar branch exited to become a subcutaneous structure. The location of this branch varied slightly in each cadaver but was the same for both lower extremities in the same cadaver. The location of the sartorial nerve and its relationship to the tendons of the pes anserinus was consistant in all 20 specimens. Since 69% of a group of 75 patients found altered sensation significant after routine sectioning of the infrapatellar nerve following medial meniscectomy, a group of surgeons at the University of Michigan is now protecting the infrapatellar branch of the saphenous nerve at operation. Early results on a small number of patients indicate that no alteration in sensation occurs if the nerve is carefully retracted.