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Fusion of the Destroyed Arthritic Knee: Compression Arthrodesis vs. Intramedullary Rod Technique
Fusion of the Destroyed Arthritic Knee Compression Arthrodesis vs. Intramedullary Rod Technique THEODORE A. POTTER, M.D. *
Probably the operation performed most commonly for a destroyed arthritic knee is arthrodesis, the purpose of which is to provide a painless, stable extremity for weight-bearing or for convalescent comfort in a "bed-chair" type patient. It is not uncommon to find a completely destroyed arthritic knee at surgery, so that the surgeon must be able to perform fusion when necessary. One can often predict the indications for arthrodesis - namely severe deformity of greater than 30 degrees valgus with flexion contracture, severe loss of femoral height due to collapsed cysts, and osteoporosis, dislocation of the knee, lateral shifting of the femur on the tibia and accompanying marked instability, and weakness of the quadriceps. Complete loss of cartilage substance, while not a strict indication for fusion, should lead to consideration of arthrodesis of the rheumatoid knee if accompanied by any of these factors. In addition, the emotionally uncooperative patient with a destroyed joint will probably best be suited for arthrodesis. There is not the painful postoperative rehabilitative period that is so necessary after other intra-articular mobilizing procedures. The undesirable effect of knee fusion is a stiff knee with the strain on the opposite knee, hip, foot, and low back. Difficulty in ambulation is not always a factor in young people, but in older patients adjustment to a new type of gait is often difficult. There are certain injuries, such as hip fracture, that occur fairly often after knee fusion. In patients with bilateral severe arthritis we usually consider fusing the worse knee and perform this procedure as an initial operation. Two to three weeks subsequently, an arthroplasty is performed on the opposite joint. The reason for this timing is to allow the fused knee a long enough interval to heal that when the arthroplasty side is ready for ambulation the fused joint will be clinically solid. Often the decision to fuse a knee must be made at the time of surgery *Chief, Orthopedic Service, Robert B. Brigham Hospital; Assistant Clinical Professor of Orthopedic Surgery, Harvard Medical School, Boston, Massachusetts Surgical Clinics of North America- Vol. 49, No.4, August, 1969
939
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A. POTTER
and the patient must be so informed preoperatively. There are many techniques utilized for fusion of the knee joint. All the older procedures require bone graft, spicas, and a long period of immobilization. In the past two decades we have employed principally two procedures, the compression technique and intramedullary rod fixation.
COMPRESSION TECHNIQUE In the compression technique the apparatus consists of an adaptive screw that fits over either two or four Steiman pins drilled through the femur and tibia (Fig. 1). After the appropriate intra-articular surgery has been completed the pins are placed in the lower femur and upper tibia, and the side screw compression apparatus is applied and tightened. A long leg cast is applied, leaving the pins free so that daily compression adjustments can be made (Fig. 2). We prefer the four-pin apparatus rather than the two-pin type because of greater control of each part of the fusion by avoiding rotation and a more constant pressure. With the technique mentioned, solid fusion has been observed in 6 weeks, but this is the exception and not the rule (Fig. 3). Patients may ambulate in the cast, but it is quite cumbersome. We have found that the compression technique is not applicable to many cases of rheumatoid arthritis for several reasons. (1) There is such osteoporosis of bone about the knee joint that the wire will cut through the tibia or the femur. (2) Pin tract soft tissue infection is noted, especially in patients with obese thighs. (3) An average hospitalization of 10 weeks was necessary in older patients to secure clinical union. (4) Some
Figure 1. Lateral x-ray view of a fibrous ankylosed rheumatoid knee jOint. The flexion deformity of 35 degrees and fixation of the patella provide a poor extremity for ambulation. Note the narrowed joint space with condensation of bone about it and loss of condylar rounded contours.
FUSION OF THE DESTROYED ARTHRITIC KNEE
Figure 2. X-ray film of the same patient as in Figure 1 after fusion and application of the four Steinman pin compression apparatus. Note that the pins are slightly bent, affording constant compression and that the leg is held further by a plaster cast.
Figure 3. The same patient 12 weeks after arthrodesis. Note the compactness of bone about the old joint line and beginning obliteration of this area, denoting progress of fusion.
941
942
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POTTER
cases had delayed union; x-ray films failed to show lines of closure, even at 6 to 8 months.
INTRAMEDULLARY TECHNIQUE In conceiving the concept of contact compression, using an intramedullary Kunscher rod, it occurred to me that we should obviate external devices, eliminate bone grafts, and allow early weight-bearing so that the convalescence and hospital stay could be shortened. There has been described a technique of intramedullary rod fixation using a long nail driven down through the trochanter and entire femur, thus transecting the knee joint. Entrance to the femoral shaft has been accomplished through an osseous window. This approach had little appeal to us because of the high incidence of shaft fractures and, moreover, the technical difficulties of rod insertion. Therefore, our technique of fusion and the introduction of an intramedullary rod retrograde through the tibia is about the same technique as when first described over 15 years ago.! There have been a few minor changes in the operation. The procedure is performed under a tourniquet. The first incision over the knee is medial and parapatellar, but the upper part is slightly shorter than the one utilized for arthroplasty or synovectomy operations. The joint is opened through the capsule and the quadriceps tendon is separated from the vastus medialis muscle. Often the patella is adherent to the intracondylar groove and it is necessary to separate it with a chisel. After this is done the joint is flexed at 90 degrees for thorough inspection of the area. No synovectomy or debridement is carried out. The menisci and cruciate ligaments, if present, are removed for complete visualization of the joint. Using a broad osteotome the end of the femur is cut transversely at right angles to the axis. This usually can be performed best from the side-Le., from lateral to medial condyles. One can go through the anteroposterior route, but the uneven removal of bone has a tendency to lead to an angulated type of fusion in flexion. We believe that the best functioning position for the arthrodesed knee is at about 10 degrees of flexion. The upper tibia is cut transversely from front to back, care being taken not to fracture the posterior tibial lip. The joint is then extended to test the fit of each cut and a final check is carried out in regard to the degree of fusion at any correction of lateral angulation. The bone removed can be saved for packing about the joint at the end of the procedure, but this is hardly necessary because the final fit is so tight that there is usually no room for extra bone. The posterior surface of the patella is denuded, as is the intracondylar notched area to receive it (Fig. 4). The rod site is prepared in the following manner: a 3/8 inch osteotome is used to form the starter hole in the tibia. With the knee acutely flexed, a hole 3/8 inch square is made in the cut surface of the midline of the tibia, 1f2 inch back from the anterior cortical surface. This starter hole is carried down in the medullary portion just behind the tibial crest cortex. A long metal sound can then be introduced into the tibial medullary canal to the ankle joint; this is done to test the width of the canal
943
FUSION OF THE DESTROYED ARTHRITIC KNEE
o E
F
Figure 4. Surgical steps to be followed in arthrodesis of the knee by intramedullary rod technique. A, Articular surfaces cut squarely across the faces of each joint compartment. B, Notching of both tibia and femur to receive the rod. C, Long intramedullary drill introduced to ream out tibial canal and metal sound to determine the length of the medullary hole, the distal part of which stops at the articular plate of the ankle. D, Introduction of 32 cm. Kunscher rod with outside skin marking rod. E, Lower tibial incision. F, Window devised in cortex of lower tibia by double bladed reciprocating saw. G, Retrograde introduction of Kunscher rod to a point where it becomes equidistant across the fusion area.
and to see whether or not there is a narrow portion. Then an appropriate long boring drill, somewhat smaller than the size of the Kunscher rod, is drilled into the tibial substance to the articular plate of the ankle joint without entering this joint. We have found that a Vitallium Kunscher rod, 32 cm.long by 11 mm. wide, is the sort most commonly accepted in this adult knee fusion procedure. This then is introduced by hand, point first, downward into the tibia, making sure that the canal is clear. It has been found that this length of rod will just be about 2.5 cm. longer than the tibial canal, and it affords easy introduction into the femur. With the rod in place, and using another rod externally as a marker, the location of the distal end is scribed on the skin with a sterile pencil. The rod is then removed and the knee is extended. A second incision is made over the lower end of the tibia, curving medially, about 4 inches in length, to expose the inner aspect of the tibia by subperiosteal dissection. Then, using a double-bladed round oscillating saw, a 4 inch window is cutin the tibia the same width as the rod-II mm. wide. The cortex window is removed from the tibia. Then the knee is flexed and a similar hole is cut in the anterior surface of the femur, 1f2 inch back from the anterior cortex and 3/8 inch in diameter. The rod
944
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POTTER
is introduced, slot first (Le., blunt end downward in a reversed fashion), into the hole of the tibia and driven the full length of this bone down into the slot above the ankle. The knee is then extended and the sharp end of the rod is driven into the hole previously made in the femur. Using a malleable driver through the tibial slot, the rod is introduced retrograde across the fused knee until the length of the rod is equidistant across the joint. At this point, the knee joint will be in 10 degrees of flexion and the operator will note that it is quite solidly immobilized (Fig. 5). Closure of the lower wound and reinsertion of the cortical window is accomplished and the main wound is closed by interrupted silk sutures for the deeper structures and nylon for the skin. A long leg cast is applied and the tourniquet is removed. Postoperatively, the care consists of elevation of the leg for 1 week. Considerable edema may develop at the lower end of the incision, so that the cast is bivalved in 48 hours to inspect the wound and change the dressings. The sutures are removed in 12 days, and a walking cylinder is applied. Thereafter, the patient will walk with full weight-bearing on crutches and is discharged from the hospital 3 weeks after operation. The walking cylinder may be utilized for a period of 8 weeks, at which time x-rays films show beginning lines of closure and clinically the limb is quite solid. The results in 53 knee fusions with various techniques have been gratifying. Over a 15 year period 49 patients obtained solid fusion without incident; 2 patients were graded as good, with delayed union up to 9 months, and 2 pati,ents were graded as fair. In this group one had a wound infection, necessitating removal of the rod, but eventually the soft tissue wound was secured, and another patient developed a permanent peroneal palsy. This was caused by a correction of greater than 50
Figure 5. Lateral x-ray view of knee arthrodesis with Kunscher rod placed equidistant across the fusion line and the knee in about 10 degrees of flexion.
FUSION OF THE DESTROYED ARTHRITIC KNEE
945
per cent of the deformity at one stage. There undoubtedly was permanent traction on the peroneal nerve. The complications thus far for this operation have been peroneal palsy and wound infection and delayed union, in one case each. However, the ease of recovery and rapidity of fusion plus the short hospital stay far outweighs these negating factors in this type of operation. In summary, destroyed arthritic knees that are painful and unstable, with marked deformities and bony changes, should be considered for arthrodesis. In our experience contact compression using the intramedullary rod technique has given gratifying results in 49 patients subjected to knee fusion.
REFERENCE 1. Hollander, J. E.: Arthritis. 6th ed. Philadelphia, Lea & Febiger, 1953.
SUPPLEMENTARY BIBLIOGRAPHY Bosworth, D. M.: Knee fusion by the use of a three-flanged nail. J. Bone Joint Surg., 28:550554 (July), 1946. Chapchal, G.: Intramedullary pinning for arthrodesis of the knee jOint. J. Bone Joint Surg., 30-A:728-734 (July), 1948. Charnley, J. C.: Positive pressure in arthrodesis of the knee jOint. J. Bone Joint Surg., 30-B: 478-486 (Aug.), 1948. Charnley, J. C.: Compression Arthrodesis. Edinburgh and London, E. & S. Livingstone, 1953. Charnley, J. C., and Baker, S. L.: Compression arthrodesis of the knee. A clinical and histological study. J. Bone Joint Surg., 34-B:187-199 (May), 1952. Charnley, J. C., and Lowe, H. G.: A study of end results of compression arthrodesis of the knee. J. Bone Joint Surg., 40-B :633-635 (Nov.), 1958. Fett, H. C., and Zorn, E. L.: Compression arthrodesis of the knee. J. Bone Joint Surg., 35-A: 172-177 (Jan.), 1953. Galloway, H. P. H.: The patellar bone graft in excision of the knee. Amer. J. Orthop. Surg., 15:704-710 (Oct.), 1917. Gray, R T.: The stabilization of the flail leg. Brit. J. Surg., 15 :390-400, 1927. Ha!llada, G.: Intermittent compression arthrodesis of the knee; a preliminary report. J. Bone Joint Surg., 37-A:95-98 (Jan.), 1955. Hatt, R N.: The central bone graft injoint arthrodesis. J. Bone Joint Surg., 22 :393-402 (April), 1940. Henderson, M. S., and Forten, H. J.: Tuberculosis of the knee joint in the adult. J. Bone Joint Surg., 9:700-713 (Oct.), 1927. Hibbs, R A.: An operation for stiffening the knee joint with report of cases from the service of the New York Orthopedic Hospital. Ann. Surg., 53 :404-407,1911. Kaplan, C. J.: Compression arthrodesis of the knee joint. J. Bone Joint Surg., 35-A:781-784 (July), 1953. Key, J. A.: Positive pressure arthrodesis for tuberculosis of the knee joint. South. Med. J., 25 :909-915, 1932. Key, J. A.: Arthrodesis of the knee with a large central autogenous bone peg. South Med. J., 30:574-579,1937. Lucas, D. B., and Murray, W. R: Arthrodesis of the knee by double plating. J. Bone Joint Surg., 43-A:795-808 (Sept.), 1961. Marcus, J., Stewart, W., and Griffin, B.: Compression in arthrodesis. J. Bone Joint Surg., 40-A: 585-606 (June), 1958. Mazzetti, R F.: Effect of immobilization of the knee on energy expenditure during walking. J. Bone Joint Surg., 42-A:533 (April), 1960. Milgram, J. E.: A modification of the rotation arthrodesis of the knee (Roeren). Surg. Gynec. Obstet., 53 :355-359, 1931. Morris, H. D., and Morisman, R S.: Arthrodesis of the knee. J. Bone Joint Surg., 33-A:982987 (Oct.), 1951. 125 Parker Hill Avenue Boston, Massachusetts 02120
Probably the operation performed most commonly for a destroyed arthritic knee is arthrodesis, the purpose of which is to provide a painless, stable extremity for weight-bearing or for convalescent comfort in a "bed-chair" type patient. It is not uncommon to find a completely destroyed arthritic knee at surgery, so that the surgeon must be able to perform fusion when necessary. One can often predict the indications for arthrodesis - namely severe deformity of greater than 30 degrees valgus with flexion contracture, severe loss of femoral height due to collapsed cysts, and osteoporosis, dislocation of the knee, lateral shifting of the femur on the tibia and accompanying marked instability, and weakness of the quadriceps. Complete loss of cartilage substance, while not a strict indication for fusion, should lead to consideration of arthrodesis of the rheumatoid knee if accompanied by any of these factors. In addition, the emotionally uncooperative patient with a destroyed joint will probably best be suited for arthrodesis. There is not the painful postoperative rehabilitative period that is so necessary after other intra-articular mobilizing procedures. The undesirable effect of knee fusion is a stiff knee with the strain on the opposite knee, hip, foot, and low back. Difficulty in ambulation is not always a factor in young people, but in older patients adjustment to a new type of gait is often difficult. There are certain injuries, such as hip fracture, that occur fairly often after knee fusion. In patients with bilateral severe arthritis we usually consider fusing the worse knee and perform this procedure as an initial operation. Two to three weeks subsequently, an arthroplasty is performed on the opposite joint. The reason for this timing is to allow the fused knee a long enough interval to heal that when the arthroplasty side is ready for ambulation the fused joint will be clinically solid. Often the decision to fuse a knee must be made at the time of surgery *Chief, Orthopedic Service, Robert B. Brigham Hospital; Assistant Clinical Professor of Orthopedic Surgery, Harvard Medical School, Boston, Massachusetts Surgical Clinics of North America- Vol. 49, No.4, August, 1969
939
940
THEODORE
A. POTTER
and the patient must be so informed preoperatively. There are many techniques utilized for fusion of the knee joint. All the older procedures require bone graft, spicas, and a long period of immobilization. In the past two decades we have employed principally two procedures, the compression technique and intramedullary rod fixation.
COMPRESSION TECHNIQUE In the compression technique the apparatus consists of an adaptive screw that fits over either two or four Steiman pins drilled through the femur and tibia (Fig. 1). After the appropriate intra-articular surgery has been completed the pins are placed in the lower femur and upper tibia, and the side screw compression apparatus is applied and tightened. A long leg cast is applied, leaving the pins free so that daily compression adjustments can be made (Fig. 2). We prefer the four-pin apparatus rather than the two-pin type because of greater control of each part of the fusion by avoiding rotation and a more constant pressure. With the technique mentioned, solid fusion has been observed in 6 weeks, but this is the exception and not the rule (Fig. 3). Patients may ambulate in the cast, but it is quite cumbersome. We have found that the compression technique is not applicable to many cases of rheumatoid arthritis for several reasons. (1) There is such osteoporosis of bone about the knee joint that the wire will cut through the tibia or the femur. (2) Pin tract soft tissue infection is noted, especially in patients with obese thighs. (3) An average hospitalization of 10 weeks was necessary in older patients to secure clinical union. (4) Some
Figure 1. Lateral x-ray view of a fibrous ankylosed rheumatoid knee jOint. The flexion deformity of 35 degrees and fixation of the patella provide a poor extremity for ambulation. Note the narrowed joint space with condensation of bone about it and loss of condylar rounded contours.
FUSION OF THE DESTROYED ARTHRITIC KNEE
Figure 2. X-ray film of the same patient as in Figure 1 after fusion and application of the four Steinman pin compression apparatus. Note that the pins are slightly bent, affording constant compression and that the leg is held further by a plaster cast.
Figure 3. The same patient 12 weeks after arthrodesis. Note the compactness of bone about the old joint line and beginning obliteration of this area, denoting progress of fusion.
941
942
THEODORE
A.
POTTER
cases had delayed union; x-ray films failed to show lines of closure, even at 6 to 8 months.
INTRAMEDULLARY TECHNIQUE In conceiving the concept of contact compression, using an intramedullary Kunscher rod, it occurred to me that we should obviate external devices, eliminate bone grafts, and allow early weight-bearing so that the convalescence and hospital stay could be shortened. There has been described a technique of intramedullary rod fixation using a long nail driven down through the trochanter and entire femur, thus transecting the knee joint. Entrance to the femoral shaft has been accomplished through an osseous window. This approach had little appeal to us because of the high incidence of shaft fractures and, moreover, the technical difficulties of rod insertion. Therefore, our technique of fusion and the introduction of an intramedullary rod retrograde through the tibia is about the same technique as when first described over 15 years ago.! There have been a few minor changes in the operation. The procedure is performed under a tourniquet. The first incision over the knee is medial and parapatellar, but the upper part is slightly shorter than the one utilized for arthroplasty or synovectomy operations. The joint is opened through the capsule and the quadriceps tendon is separated from the vastus medialis muscle. Often the patella is adherent to the intracondylar groove and it is necessary to separate it with a chisel. After this is done the joint is flexed at 90 degrees for thorough inspection of the area. No synovectomy or debridement is carried out. The menisci and cruciate ligaments, if present, are removed for complete visualization of the joint. Using a broad osteotome the end of the femur is cut transversely at right angles to the axis. This usually can be performed best from the side-Le., from lateral to medial condyles. One can go through the anteroposterior route, but the uneven removal of bone has a tendency to lead to an angulated type of fusion in flexion. We believe that the best functioning position for the arthrodesed knee is at about 10 degrees of flexion. The upper tibia is cut transversely from front to back, care being taken not to fracture the posterior tibial lip. The joint is then extended to test the fit of each cut and a final check is carried out in regard to the degree of fusion at any correction of lateral angulation. The bone removed can be saved for packing about the joint at the end of the procedure, but this is hardly necessary because the final fit is so tight that there is usually no room for extra bone. The posterior surface of the patella is denuded, as is the intracondylar notched area to receive it (Fig. 4). The rod site is prepared in the following manner: a 3/8 inch osteotome is used to form the starter hole in the tibia. With the knee acutely flexed, a hole 3/8 inch square is made in the cut surface of the midline of the tibia, 1f2 inch back from the anterior cortical surface. This starter hole is carried down in the medullary portion just behind the tibial crest cortex. A long metal sound can then be introduced into the tibial medullary canal to the ankle joint; this is done to test the width of the canal
943
FUSION OF THE DESTROYED ARTHRITIC KNEE
o E
F
Figure 4. Surgical steps to be followed in arthrodesis of the knee by intramedullary rod technique. A, Articular surfaces cut squarely across the faces of each joint compartment. B, Notching of both tibia and femur to receive the rod. C, Long intramedullary drill introduced to ream out tibial canal and metal sound to determine the length of the medullary hole, the distal part of which stops at the articular plate of the ankle. D, Introduction of 32 cm. Kunscher rod with outside skin marking rod. E, Lower tibial incision. F, Window devised in cortex of lower tibia by double bladed reciprocating saw. G, Retrograde introduction of Kunscher rod to a point where it becomes equidistant across the fusion area.
and to see whether or not there is a narrow portion. Then an appropriate long boring drill, somewhat smaller than the size of the Kunscher rod, is drilled into the tibial substance to the articular plate of the ankle joint without entering this joint. We have found that a Vitallium Kunscher rod, 32 cm.long by 11 mm. wide, is the sort most commonly accepted in this adult knee fusion procedure. This then is introduced by hand, point first, downward into the tibia, making sure that the canal is clear. It has been found that this length of rod will just be about 2.5 cm. longer than the tibial canal, and it affords easy introduction into the femur. With the rod in place, and using another rod externally as a marker, the location of the distal end is scribed on the skin with a sterile pencil. The rod is then removed and the knee is extended. A second incision is made over the lower end of the tibia, curving medially, about 4 inches in length, to expose the inner aspect of the tibia by subperiosteal dissection. Then, using a double-bladed round oscillating saw, a 4 inch window is cutin the tibia the same width as the rod-II mm. wide. The cortex window is removed from the tibia. Then the knee is flexed and a similar hole is cut in the anterior surface of the femur, 1f2 inch back from the anterior cortex and 3/8 inch in diameter. The rod
944
THEODORE
A.
POTTER
is introduced, slot first (Le., blunt end downward in a reversed fashion), into the hole of the tibia and driven the full length of this bone down into the slot above the ankle. The knee is then extended and the sharp end of the rod is driven into the hole previously made in the femur. Using a malleable driver through the tibial slot, the rod is introduced retrograde across the fused knee until the length of the rod is equidistant across the joint. At this point, the knee joint will be in 10 degrees of flexion and the operator will note that it is quite solidly immobilized (Fig. 5). Closure of the lower wound and reinsertion of the cortical window is accomplished and the main wound is closed by interrupted silk sutures for the deeper structures and nylon for the skin. A long leg cast is applied and the tourniquet is removed. Postoperatively, the care consists of elevation of the leg for 1 week. Considerable edema may develop at the lower end of the incision, so that the cast is bivalved in 48 hours to inspect the wound and change the dressings. The sutures are removed in 12 days, and a walking cylinder is applied. Thereafter, the patient will walk with full weight-bearing on crutches and is discharged from the hospital 3 weeks after operation. The walking cylinder may be utilized for a period of 8 weeks, at which time x-rays films show beginning lines of closure and clinically the limb is quite solid. The results in 53 knee fusions with various techniques have been gratifying. Over a 15 year period 49 patients obtained solid fusion without incident; 2 patients were graded as good, with delayed union up to 9 months, and 2 pati,ents were graded as fair. In this group one had a wound infection, necessitating removal of the rod, but eventually the soft tissue wound was secured, and another patient developed a permanent peroneal palsy. This was caused by a correction of greater than 50
Figure 5. Lateral x-ray view of knee arthrodesis with Kunscher rod placed equidistant across the fusion line and the knee in about 10 degrees of flexion.
FUSION OF THE DESTROYED ARTHRITIC KNEE
945
per cent of the deformity at one stage. There undoubtedly was permanent traction on the peroneal nerve. The complications thus far for this operation have been peroneal palsy and wound infection and delayed union, in one case each. However, the ease of recovery and rapidity of fusion plus the short hospital stay far outweighs these negating factors in this type of operation. In summary, destroyed arthritic knees that are painful and unstable, with marked deformities and bony changes, should be considered for arthrodesis. In our experience contact compression using the intramedullary rod technique has given gratifying results in 49 patients subjected to knee fusion.
REFERENCE 1. Hollander, J. E.: Arthritis. 6th ed. Philadelphia, Lea & Febiger, 1953.
SUPPLEMENTARY BIBLIOGRAPHY Bosworth, D. M.: Knee fusion by the use of a three-flanged nail. J. Bone Joint Surg., 28:550554 (July), 1946. Chapchal, G.: Intramedullary pinning for arthrodesis of the knee jOint. J. Bone Joint Surg., 30-A:728-734 (July), 1948. Charnley, J. C.: Positive pressure in arthrodesis of the knee jOint. J. Bone Joint Surg., 30-B: 478-486 (Aug.), 1948. Charnley, J. C.: Compression Arthrodesis. Edinburgh and London, E. & S. Livingstone, 1953. Charnley, J. C., and Baker, S. L.: Compression arthrodesis of the knee. A clinical and histological study. J. Bone Joint Surg., 34-B:187-199 (May), 1952. Charnley, J. C., and Lowe, H. G.: A study of end results of compression arthrodesis of the knee. J. Bone Joint Surg., 40-B :633-635 (Nov.), 1958. Fett, H. C., and Zorn, E. L.: Compression arthrodesis of the knee. J. Bone Joint Surg., 35-A: 172-177 (Jan.), 1953. Galloway, H. P. H.: The patellar bone graft in excision of the knee. Amer. J. Orthop. Surg., 15:704-710 (Oct.), 1917. Gray, R T.: The stabilization of the flail leg. Brit. J. Surg., 15 :390-400, 1927. Ha!llada, G.: Intermittent compression arthrodesis of the knee; a preliminary report. J. Bone Joint Surg., 37-A:95-98 (Jan.), 1955. Hatt, R N.: The central bone graft injoint arthrodesis. J. Bone Joint Surg., 22 :393-402 (April), 1940. Henderson, M. S., and Forten, H. J.: Tuberculosis of the knee joint in the adult. J. Bone Joint Surg., 9:700-713 (Oct.), 1927. Hibbs, R A.: An operation for stiffening the knee joint with report of cases from the service of the New York Orthopedic Hospital. Ann. Surg., 53 :404-407,1911. Kaplan, C. J.: Compression arthrodesis of the knee joint. J. Bone Joint Surg., 35-A:781-784 (July), 1953. Key, J. A.: Positive pressure arthrodesis for tuberculosis of the knee joint. South. Med. J., 25 :909-915, 1932. Key, J. A.: Arthrodesis of the knee with a large central autogenous bone peg. South Med. J., 30:574-579,1937. Lucas, D. B., and Murray, W. R: Arthrodesis of the knee by double plating. J. Bone Joint Surg., 43-A:795-808 (Sept.), 1961. Marcus, J., Stewart, W., and Griffin, B.: Compression in arthrodesis. J. Bone Joint Surg., 40-A: 585-606 (June), 1958. Mazzetti, R F.: Effect of immobilization of the knee on energy expenditure during walking. J. Bone Joint Surg., 42-A:533 (April), 1960. Milgram, J. E.: A modification of the rotation arthrodesis of the knee (Roeren). Surg. Gynec. Obstet., 53 :355-359, 1931. Morris, H. D., and Morisman, R S.: Arthrodesis of the knee. J. Bone Joint Surg., 33-A:982987 (Oct.), 1951. 125 Parker Hill Avenue Boston, Massachusetts 02120