CHAPTER XLI. (Part 1)

CHAPTER XLI. FRACTURES OF THE PATELLA. Surgical Anatomy. — The patella is a sesamoid bone developed in the tendon of the quadriceps extensor femoris. It is usually ossi- fied from one center, which makes its appearance about the third year. In rare instances it is developed from two centers, laterally placed. The patella is attached to the tubercle of the tibia by the ligamentum patellae, Avhich maintains the bone at a constant dis- tance from the tibia. The anterior surface is subcutaneous except for the prepatellar bursa which is interposed between the bone and the skin. The patella is covered on all sides, except the articular surface, by the tendon of the quadriceps which is spoken of below the bone as the ligamentum patellae. In extension of the knee the articular surface of the patella is in contact with the trochlear surface of the femur ; in flexion, with the condyles. The lower portion of the patella or apex has attached to it, both anteriorly and posteriorly, the fibres of the ligamentum patellae. The patella is situated in two fibrous planes; the superficial one is represented by the fascia lata covering the quadriceps extensor, the deep plane is the capsule of the knee-joint. When fracture occurs separation of the fragments does not take place unless the fascial planes, in which the bone is situated, are torn. The func- tion of the patella is to afford leverage to the tendon of the quadri- ceps, while acting across the flexed knee. The insertion of this muscle is chiefly into the patellar ligament, but it should not be taken for granted that the quadriceps acts only through the patella, since it finds a broad insertion into the upper end of the tibia through the fascia lata and capsule. In instances, therefore, in which the patella is fractured without tearing of the fasciae on either side of it, the patient still retains some power in extending the knee. The mechanism of fracture of the patella has been the subject of considerable discussion, and even at the present time differences of opinion exist concerning it. The bone may be broken by direct 594 FRACTURES OP THE PATELLA 595 violence, or by mnsciilar action. When the former is the cause the fracture is often stellate or irregular and comminuted, depend- ing upon the nature, direction and degree of the trauma. In this type of fracture the lateral fasciae are seldom torn and the dis- placement is slight. Fracture produced in this way sometimes re- sults in injury to the underlying articular surface of the femur. When fracture results from muscular action it is caused by the violent action of the quadriceps extensor on the patella while the knee is flexed. In this way the patella is broken across the con- dyles of the femur, and if the muscle continues to act, the frag- ments are separated and the lateral fasciae torn. The mechanism of fracture of this bone, as a result of muscular action, may be illustrated by the facility with which a stick can be broken across the knee when it will be impossible to part this same stick by simple traction and counter-traction in its long axis. If a blow is sustained on the flexed knee (either by a moving object or in a fall) while the muscle is contracting, the fracturing effect of the muscular pull is greatly increased. The upper end of the bone is fixed by the quadriceps and the lower end by the liga- mentum patellae, while the middle of the posterior surface is the only part of the articular face in contact with the femur during flexion. The distribution of these three forces explains the man- ner in which the patella may be snapped. Fracture of the patella nearly always enters the knee-joint, but when confined to the lower portion of the apex of the bone, which is covered by the patellar tendon, the joint is not necessarily opened. Etiology. — Transverse fracture of the bone is most common, while the comminuted form is next in order of frequency. Over four- fifths of all fractures of the patella are in the lower half of the bone. This accident occurs more often between the ages of thirty and forty, and is three times as common in males. Muscular action is probably responsible for more cases than is direct violence, al- though a combination of these two elements is not at all uncommon. Symptoms. — Local pain is constant, with partial or complete loss of extension at the knee. The patient is sometimes able to walk backward by dragging the foot and keeping the knee hyperex- tended. If weight is put upon the leg, with the slightest degree of flexion at the knee, the lower extremity buckles and the patient falls. The condition is usually simple, although in severe crushing or cutting injuries the fracture may be compound and the joint 596 FRACTURES AND DISLOCATIONS exposed. Crepitus may be elicited in the absence of separation, or if the parted fragments are drawn toward each other and the Fig. 658. — Old fracture of patella with separation of fragments. Recent fracture of the femoral neck, which accounts for the complete eversion of the entire lower extrem- ity. The front of the knee looks outward instead of upward and the depression between the fragments of the patella is just above the point of the arrow. serrated surfaces rubbed together. Some degree of separation is usually present, which in many instances can be detected by in- spection alone if the case is seen before the parts become exten- sively swollen. It is often possible to lay one or two fingers in the Fig. 659. — Shows an unusual case of fracture with wide separation of both patellge. The fracture of the left patella is of three years' standing Avhile that on the opposite side is two years old. Case treated by the expectant method which resulted in fibrous union with subsequent separation of the fragments. Case first seen bv the author three years after the first fracture. depression existing between the fragments. Swelling and disten- tion of the joint follow rapidly, and obliterate the depression be- FRACTURES OF THE PATELLA 597 tweeii the fragments so that the condition cannot be recognized by inspection, although there is usually little difficulty in determining the deformity b}^ palpation. The development of ecchymosis within twelve or twenty-four hours of the injury is the rule. It is usually most pronounced on either side of the patella corresponding to the positions of the lateral fascial tears. The symptoms of acute traumatic arthritis generally supervene within a few hours of the injury. Swelling, redness, pain, tender- ness and distention of the joint are present. When the joint be- comes filled, the fluid reaches the surface between the fragments and produces a prominent swelling anterior to the patella. Dis- tention of the joint cavity causes the patient to assume a charac- teristic position of slight flexion of the knee and moderate eversion of the thigh. The later symptoms of fracture of the patella depend largely upon the line of treatment followed. Pain, swelling and tenderness are usually not severe at the end of a week or ten days, especially if measures have been instituted for their control. Bony union seldom occurs in cases which have been treated by non-operative methods and the amount of impairment in function will depend largely upon the length and strength of the fibrous union. This fibrous tissue tends to stretch with the subsequent use of the member, so that it is not uncommon for the patient to present himself for treatment at the end of a year or two because of pronounced and increasing loss of function. The separation between the fragments may be four or five inches or even more, so that the quadriceps extensor can be well contracted while the knee is still in a position of semiflexion. Secondary separation of the fragments is not prone to occur if the lateral fasciae were untorn at the time of injury. Fibrous adhesions or bony union between the articular surface of the patella and the femur, may so fix the knee cap that the thigh muscle cannot move it, thus producing loss of function of an entirely different character. Diagnosis. — The diagnosis is based on the history of injury to the knee followed by prompt loss of function and other symptoms just enumerated. Little difficulty should be experienced in recognizing the condition by inspection and palpation regardless of Avhether or not separation of the fragments exists. Even though the bone is superficial and easily palpated, nevertheless it is advisable to have an X-ray taken to accurately determine and record the details of the fracture. 598 FRACTURES AND DISLOCATIONS Treatment. — The fact that reduction of the separated fragments is indicated in the treatment of fracture of the patella, is uniformly conceded, but the proper method of attaining tliis end has been, and is, the subject of mucJi discussion. Even at the present time few surgeons agree concerning the best method of procedure. Some are opposed to opening the knee-joint as long as there is a fair prospect of obtaining some kind of a functional result by non- operative methods. Others take the position that every fracture Fig. 660. — Shows the non-operative treatment of fracture of the patella. A. shows the lower extremity fixed on a posterior splint with the knee in a position of slight flexion. The splint is a straight splint heavily padded opposite the knee. Two short splints are secured to the thigh on either side of the quadriceps to prevent contraction of this muscle. B. shows diagonal strips of adhesive applied above and below the patella to approximate the fragments. C. shows lateral splints applied. D. shows the lower extremity raised on pillows to relax the quadriceps. of the patella should be subjected to open treatment if the general condition of the patient will permit of operation. Personal ex- perience and observation have indicated that by far the best results follow the more radical measures. It is a well known fact that ex- cellent functional results are sometimes seen in instances in which wide separation and heavy fibrous union are present. But on the other hand the highest percentage of functionally perfect results is seen in cases in which accurate anatomic reduction has been accom- plished. Conclusive deductions cannot, at the present time, be FRACTURES OF THE PATELLA 599 drawn from the statistics of operated eases because of the widely varying and sometimes imperfect technique which has been fol- lowed b}' different operators. In the author's opinion, non-oper- ative treatment is only indicated in old and feeble persons, or in cases in which separation does not exist. The lack of proper sur- gical facilities and skill or the presence of certain constitutional diseases, such as diabetes, wdll of course act as contraindications to the open treatment. The first indication in the treatment of fracture of the patella, in both the operative and non-operative methods, consists in putting the lower extremity at rest and in Fig. 661. — "Shaped" ham splint with padding applied to posterior aspect of lower extremity and held in position by three strips of adhesive plaster. instituting measures to control the traumatic arthritis. The lower extremity should be placed upon a posterior splint, which is secured in position by bandages and strips of adhesive as shown in Fig. 660. A snug bandage should cover the knee to control the swell- ing, and an ice cap to the parts will be found of great service in relieving pain and modifying the inflammatory reaction. If the expectant method is to be followed adhesive straps above and below the patella are diagonally placed in such a manner as to draw the fragments together (see Fig. 660). It is useless, however, to at- tempt to approximate the fragments until the joint distention lias 600 FRACTURES AND DISLOCATIONS subsided, which will not be sooner than one week following the injury. There is no method of applying these straps, even after the fluid has left the joint, which will accurately approximate the fragments if separation has existed, notwithstanding statements to the contrary. This fact may be conclusively demonstrated by the use of the X-ray in any given case in which the fragments are supposed to have been reduced. In the rare instances in which fracture has occurred without separation of the fragments, as indi- cated by the X-ray, this method may be counted upon to give a good result. In most cases of fracture of the patella considerable separation will be found after everything which is possible in a non-operative way has been accomplished, and we therefore turn to the open treatment to secure reduction. Operative Treatment. — The open treatment of fracture of the patella is the ideal method, but should not be attempted unless one fully appreciates the untoward possibilities, and is thoroughly equipped to carry it through. If the cases, in which unsatisfactory Fig. 662. Fig. 662. — Shows tlie method of placing the silver wire mattress suture in approxi- mating the fragments in a transverse fracture of the patella. Fig. 663. — Shows a horizontal section of the patella at the same level. Note the rela- tive distribution of cancellous and compact tissue. results have followed the open treatment, are analyzed, they will be found to have resulted from one or more of three conditions, namely : infection, insecure fixation of the fragments and prolonged immobilization of the knee. Asepsis should be perfect in every detail as described under "Open Treatment of Fractures" on page 754. Infection follow- ing operations on the knee means not only failure in union, but involvement of the knee-joint which may result in loss of function in the articulation, if not amputation or death. It is common to find a clot of blood in the joint behind the fracture, which should FRACTURES OF THE PATELLA 601 be removed before the fragments are brought together. It is dan- gerous to leave this dead blood where it may favor subsequent sup- puration (see "Open Treatment of Fractures," page 754). The Fig'. 6(.i4. — Recent fracture of the patella with separation of fiii<i-nients. This near as the fragments could be brought together by non-operative methods. Fig. 665. — ^Same case after operation. A silver Avire, mattress suture draws the fragments into apposition and holds them firmly against the displacing action of the quadriceps. Ultimate result, complete restoration of function. fragments should be accurately and firmly approximated at the time of operation and so fixed that separation cannot take place during the after-treatment. Wire properly placed is the only 602 FRACTURES AND DISLOCATIONS material which can be counted on to secure proper and permanent immobilization. Absorbable suture material has been strongly ad- vocated and good results may follow its employment ; but the inse- curity resulting from its softening and absorption before the end of the third week should condemn its use in fracture of the patella. It has been used in suturing the fasciae covering the patella and in the repair of lateral fascial tears as well as in direct suturing of the bones through drill holes. Separation of the fragments is likely to occur during the second or third weeks, which can only mean failure in bony union with the possibility of further separation through stretching of the fibrous tissue. Even if chromicised cat- gut or other absorbable material could be counted on to maintain reduction until bony callus relieved it of strain, we could not rely on the sutured fascia to withstand the pull of the quadriceps dur- ing this period. It is apparent, therefore, that wire, securing a firm hold directly on the bony fragments, is the most satisfactory method of fixation. The structure of the patella should be remem- bered w^hile securing the fragments. The wire should be so placed that it obtains its hold on the compact shell, rather than on the internal cancellated tissue, which is likely to give way under strain and allow the loop of wire to tear out. This is best accomplished by a mattress suture of wire as described later on. The more se- cure the internal fixation, the safer is the early employment of passive motion ; and early passive motion is most essential in re- establishing the function of the joint. Its proper use will be de- scribed in the after-treatment. Loss of function and "painful joint" sometimes occur in cases in which proper reduction and bony union have followed the injury. These conditions are almost entirely due to the lack of early passive motion. The joint should be moved not later than two weeks from the time of operation, but passive motion has its risk, if fixation of the fragments is not solid, and should not be attempted without properly guarding the patella from the action of the quadriceps. The following technique, in operating on fractures of the patella has proven the most satisfactory in the author's hands and may be considered the procedure of preference in most cases. An in- cision is made exposing the fragments ; it may be longitudinal and directly over the fracture or of the U-shape commonly employed in operations on the knee. With the fragments exposed and sepa- rated the clot w^hich is usually found behind the fragments is re- FRACTURES OF THE PATELLA 603 moved with thumb forceps. Bony contact is essential and if fascia is found covering one of the fractured surfaces (usually the lower) it should be carefully removed before the fragments are brought together. In transverse fracture of the patella holes are drilled in each fragment so that the drill enters the anterior face of the patella and comes out on the fractured surface. Two such parallel holes are drilled in each fragment so that the openings on the Fig. 666. — Wired fi'actiire of the patella three years af^er in.iury. Funrtion as good as before